Clark Canyon Dam Hydroelectric Project; Notice of Availability of Environmental Assessment

Federal RegisterJun 29, 2016

Ask Donna

What actually matters in this document.

Text

DEPARTMENT OF ENERGY

Federal Energy Regulatory Commission

[Project No. 14677-001—Montana]

Clark Canyon Dam Hydroelectric Project; Notice of Availability of Environmental Assessment

In accordance with the National Environmental Policy Act of 1969 and the Federal Energy Regulatory Commission's (Commission or FERC) regulations, 18 CFR part 380 (Order No. 486, 52 FR 47897), Office of Energy Projects staff have reviewed Clark Canyon Hydro, LLC's application for license for the proposed Clark Canyon Dam Hydroelectric Project. The project would be located at the U.S. Bureau of Reclamation's (Reclamation's) Clark Canyon Dam, on the Beaverhead River near the city of Dillon, Beaverhead County, Montana, and would occupy a total of 62.3 acres of federal land administered by the U.S. Bureau of Reclamation and the U.S. Bureau of Land Management.

Staff have prepared an environmental assessment (EA) analyzing the potential environmental impacts of the project, and conclude that constructing and operating the project, with appropriate environmental protective measures, would not constitute a major federal action that would significantly affect the quality of the human environment.

A copy of the EA is available for review at the Commission in the Public Reference Room or may be viewed on the Commission's Web site at

http://www.ferc.gov

using the “eLibrary” link. Enter the docket number excluding the last three digits in the docket number field to access the document. For assistance, contact FERC Online Support at

FERCOnlineSupport@ferc.gov

or toll-free at 1-866-208-3676, or for TTY, 202-502-8659.

You may also register online at

http://www.ferc.gov/docs-filing/esubscription.asp

to be notified via email of new filings and issuances related to this or other pending projects. For assistance, contact FERC Online Support.

Any comments should be filed within 30 days from the date of this notice. Comments may be filed electronically via the Internet. See 18 CFR 385.2001(a)(1)(iii) and the instructions on the Commission's Web site

http://www.ferc.gov/docs-filing/efiling.asp

. Commenters can submit brief comments up to 6,000 characters, without prior registration, using the eComment system at

http://www.ferc.gov/docs-filing/ecomment.asp

. You must include your name and contact information at the end of your comments.

For assistance, please contact FERC Online Support. Although the Commission strongly encourages electronic filing, documents may also be paper-filed. To paper-file, mail comments to: Kimberly D. Bose, Secretary, Federal Energy Regulatory Commission, 888 First Street NE., Washington, DC 20426. The first page of any filing should include docket number P-14677-001.

For further information, contact Kelly Wolcott by telephone at 202-502-6480 or by email at

kelly.wolcott@ferc.gov

Dated: June 23, 2016.

Kimberly D. Bose,

Secretary.

Environmental Assessment for Hydropower License

Clark Canyon Dam Project

FERC Project No. 14677-001

Montana

Federal Energy Regulatory Commission, Office of Energy Projects, Division of Hydropower Licensing, 888 First Street NE., Washington, DC 20426.

June 23, 2016.

Table of Contents

LIST OF FIGURES

LIST OF TABLES

ACRONYMS AND ABBREVIATIONS

EXECUTIVE SUMMARY

viii

1.0 INTRODUCTION

1.1 Application

1.2 Purpose of Action and Need for Power

1.2.1 Purpose of Action

1.2.2 Need for Power

1.3 Statutory and Regulatory Requirements

1.3.1 Federal Power Act

1.3.2 Clean Water Act

1.3.3 Endangered Species Act

1.3.4 National Historic Preservation Act

1.4 Public Review and Consultation

1.4.1 Interventions

1.4.2 Comments on the License Application

2.0 PROPOSED ACTION AND ALTERNATIVES

2.1 No-Action Alternative

2.2 Applicant's Proposal

2.2.1 Proposed Project Facilities

2.2.2 Project Safety

2.2.3 Proposed Project Operation

2.2.4 Proposed Environmental Measures

2.2.5 Modifications to Applicant's Proposal—Mandatory Conditions

2.3 Staff Alternative

3.0 ENVIRONMENTAL ANALYSIS

3.1 General Description of the River Basin

3.2 Scope of Cumulative Effects

3.2.1 Geographic Scope

3.2.2 Temporal Scope

3.3 Proposed Action and Action Alternatives

3.3.1 Geologic and Soil Resources

3.3.2 Aquatic Resources

3.3.3 Terrestrial Resources

3.3.4 Threatened and Endangered Species

3.3.5 Recreation, Land Use, and Aesthetics

3.3.6 Cultural Resources

3.4 No-Action Alternative

4.0 DEVELOPMENTAL ANALYSIS

4.2.1 No-action Alternative

4.2.2 Applicant's Proposal

4.2.3 Staff Alternative

5.0 CONCLUSIONS AND RECOMMENDATIONS

5.1 Comparison of Alternatives

5.2 Comprehensive Development and Recommended Alternative

5.3 Unavoidable Adverse Effects

108

5.4 Summary of Section 10(j) Recommendations and 4(e) conditions

108

5.4.1 Recommendations of Fish and Wildlife Agencies

108

5.4.2 Land Management Agency's Section 4(e) Conditions

112

5.5 Consistency with Comprehensive Plans

112

6.0 FINDING OF NO SIGNIFICANT IMPACT

113

7.0 LITERATURE CITED

114

8.0 LIST OF PREPARERS

121

List of Figures

Figure 1. Location of Clark Canyon Dam Hydroelectric Project

Figure 2. Clark Canyon Dam Project features

Figure 3. Beaverhead River hydrograph at Clark Canyon Dam, 1965 to 2007 and 2001 to 2005

Figure 4. Clark Canyon Dam Daily Reservoir Discharge, 1965 to 2014

Figure 5. Daily average water temperatures in the Beaverhead River measured at the site located 300 feet downstream of Clark Canyon Dam in 2013

Figure 6. Minimum oxygen levels measured during monthly 48-hour continuous sampling periods at five sites in the lower Beaverhead River between May 2007 and November 2008 downstream from the Clark Canyon Dam

Figure 7. Daily minimum dissolved oxygen levels in the Beaverhead River measured at the site located 300 feet downstream of Clark Canyon Dam

Figure 8 Discharge and total dissolved gas concentrations in the Beaverhead River downstream of Clark Canyon Dam during periodic sampling, October 2007 through December 2009

Figure 9. Average turbidity values measured during monthly 48-hour continuous sampling periods at five sites in the lower Beaverhead River between May 2007 and November 2008

Figure 10. Relative abundance of age 1+ rainbow and brown trout in the Hildreth section (RM 74.9 and 73.3 of the Beaverhead River below Clark Canyon Dam, 1991-2013

Figure 11. Recreation access sites in the vicinity of the proposed Clark Canyon Dam Hydroelectric Project

List of Tables

Table 1. Major statutory and regulatory requirements for the Clark Canyon Dam Hydroelectric Project

Table 2. Numeric water quality criteria applicable to the Clark Canyon Dam Hydroelectric Project

Table 3. Clark Canyon Reservoir release guidelines

Table 4. Water Quality Monitoring During Operation (source: license application as modified by staff)

Table 5. Parameters for the economic analysis of the Clark Canyon Dam Hydroelectric Project

Table 6. Costs of environmental mitigation and enhancement measures considered in assessing the environmental effects of constructing and operating the Clark Canyon Dam Hydroelectric Project

Table 7. Fish and wildlife agency recommendations

109

Acronyms and Abbreviations

AIR additional information request

APLIC Avian Power Line Interaction Committee

APE Area of Potential Effect

applicant Clark Canyon Hydro, LLC

BLM U.S. Bureau of Land Management

BMPs best management practices

°C degrees Celsius

certification Section 401 Water Quality Certification

CFR Code of Federal Regulations

cfs cubic feet per second

Commerce U.S. Department of Commerce

Commission Federal Energy Regulatory Commission

CWA Clean Water Act

CWQMP Construction Water Quality Monitoring Plan

District East Bench Irrigation District

DO dissolved oxygen

Revised DOEP Revised Dissolved Oxygen Enhancement Plan

EA environmental assessment

ESA Endangered Species Act

ESCP Erosion and Sediment Control Plan

°F degrees Fahrenheit

FERC Federal Energy Regulatory Commission

FPA Federal Power Act

FWS U.S. Fish and Wildlife Service

HPMP Historic Properties Management Plan

Interior U.S. Department of the Interior

IPaC Information, Planning, and Conservation system

kWh kilowatt-hour

kV kilovolt

L&WCF Land and Water Conservation Fund

mg/L milligram per liter

Montana DEQ Montana Department of Environmental Quality

Montana DFWP Montana Department of Fish, Wildlife and Parks

Montana DNRC Montana Department of Natural Resources and Conservation

Montana NHP Montana Natural Heritage Program

MOU Memorandum of Understanding

msl mean sea level

MW megawatt

MWh megawatt-hour

National Register National Register of Historic Places

NERC North American Electric Reliability Council

NHPA National Historic Preservation Act of 1966

NTU nephelometric turbidity unit

NWPP Northwest Power Pool

P-12429 FERC Project No. 12429

PA Programmatic Agreement

Park Service National Park Service

project Clark Canyon Dam Project

Reclamation U.S. Bureau of Reclamation

RM river mile

ROW right-of-way

SHPO State Historic Preservation Officer

SOC Species of Concern

TCP traditional cultural property

TDG total dissolved gas

TMDL total maximum daily load

ULT Ute ladies'-tresses

VMP Vegetation Management Plan

VRMP Visual Resources Management Plan

EXECUTIVE SUMMARY

Proposed Action

On November 23, 2015, Clark Canyon Hydro, LLC (applicant) filed an application to construct and operate the 4.7-megawatt (MW) Clark Canyon Dam Hydroelectric Project (project). The project would be located at the U.S. Bureau of Reclamation's (Reclamation's) Clark Canyon Dam on the Beaverhead River, near the city of Dillon, Montana.

The proposed project would occupy a total of 62.3 acres of federal land managed by Reclamation and the U.S. Bureau of Land Management.

The applicant supplemented its application on December 10, 2015; February 1, 2016; February 9, 2016; and March 11, 2016.

Existing Reclamation Facilities

Reclamation's Clark Canyon Dam and Reservoir is a flood control and water conservation facility located at the head of the Beaverhead River

in southwestern Montana. Clark Canyon Dam was completed in 1964 as part of Reclamation's Pick-Sloan Missouri River Basin Program, East Bench Unit. It is managed to provide irrigation storage, flood control, and recreation opportunities.

Red Rock River and Horse Prairie Creek flow into Clark Canyon reservoir; reservoir releases form the head of the Beaverhead River.

Clark Canyon Dam is a 2,950-foot long, 147.5-foot high, zoned, earth-fill structure, with an uncontrolled spillway at a crest elevation of 5,578 feet mean sea level (msl). The reservoir has a volume of 257,152 acre-feet at the flood control pool elevation of 5,560.5 msl. The dam includes an intake structure and conduit located within the reservoir that leads to a shaft house at the dam crest. From the shaft house, a 9-foot-diameter outlet conduit carries water through the dam approximately 360 feet and discharges it into a stilling basin. The discharge capacity of the outlet works is 2,325 cubic feet per second (cfs) at a reservoir water surface elevation of 5,547 feet msl. Reclamation manages approximately 15 recreation sites at Clark Canyon Reservoir and just downstream of the dam, including fishing access, campgrounds, day-use areas, boat ramps, and an overlook.

Proposed Project Facilities

The proposed Clark Canyon Dam Hydroelectric Project would use the existing dam, reservoir, intake and outlet works, and stilling basin. The proposed project would involve the installation of a new 360-foot long, 8-foot diameter steel lining within Reclamation's outlet works from the existing gate chamber to the stilling basin. At the river end of the liner, a trifurcation would separate flows into two 8-foot-diameter, 35-foot-long steel penstocks leading to a new powerhouse and a new 10-foot long, 8-foot diameter steel outlet pipe that would discharge into the stilling basin through a fixed cone valve.

The 46-foot by 65-foot concrete powerhouse would be located at the toe of the dam adjacent to the stilling basin and contain two 2.35-megawatt (MW) vertical Francis-type turbine/generator units, for a total installed capacity of 4.7 MW. Water discharged from the turbines would pass through 25-foot-long steel draft tubes that would transition into a concrete draft tube and tailrace channel discharging into the stilling basin. An aeration basin, consisting of three 45-foot-long, 10-foot-wide frames containing 330 diffusers would be installed in the stilling basin to inject air into the water column to elevate DO levels by a maximum of 7.5 milligrams per liter above reservoir conditions at the intake before the water enters the Beaverhead River. Power would be carried through a 1,100-foot-long underground transmission line from the powerhouse to a new substation containing step-up transformers and switchgear, and from there along a 7.9-mile-long overhead transmission line to the existing Peterson Flat substation (the point of interconnection).

The fixed cone value would provide a controlled release of flows when the powerhouse is offline or when the flow requirements are greater than the turbine capacity.

Proposed Operation

The project would operate in a run-of-release mode, meaning the project would operate only using flows made available by Reclamation in accordance with its standard practices and procedures; thus project operation would not affect storage or reservoir levels. The project would be operated automatically, but an operator would be on site daily.

Power generation would be seasonally dictated by Reclamation's operations. The project would be able to operate with flow release ranging from 87.5 to 700 cfs (minimum capacity of 87.5 cfs and a maximum capacity of 350 cfs per unit totaling 700 cfs). Flows less than the 87.5-cfs would cause the isolation valve in the penstock to close, allowing all flows to bypass the powerhouse and pass through the existing outlet works into the stilling basin. When the project is operating at maximum capacity, any inflows in excess of 700 cfs would bypass the powerhouse and continue to flow through Reclamation's existing outlet works and over its spillway into the stilling basin. The proposed project would generate up to 15,400 megawatt-hours (MWh) annually.

Proposed Environmental Measures

The applicant proposes the following environmental measures to protect or enhance aquatic, terrestrial, cultural, recreational and visual resources during project design, construction, and operation:

• Implement the Erosion and Sediment Control Plan (ESCP) filed with the license application to minimize soil erosion and dust, protect water quality, and minimize turbidity in the Beaverhead River;

• Implement the Instream Flow Release Plan filed with the license application with provisions to temporarily pump flows around Reclamation's existing intake and outlet works to prevent interrupting Reclamation's flow releases into the Beaverhead River during installation of the proposed project's penstock;

• Maintain compliance monitoring staff on site 24 hours per day and 7 days per week when bypassing flows around Reclamation's intake and outlet works to ensure prompt response to a pumping equipment failure or malfunction and Reclamation's flow releases are maintained in the Beaverhead River downstream.

• Implement the Construction Water Quality Monitoring Plan (CWQMP) filed with the license application that includes monitoring and reporting water temperature, dissolved oxygen (DO), total dissolved gas (TDG), and turbidity levels during construction to protect aquatic resources during construction;

• Implement the Revised Dissolved Oxygen Enhancement Plan (Revised DOEP) filed with the license application that includes installing and operating the aeration basin and monitoring and reporting of water temperature, DO, and TDG levels for a minimum of the first five years of project operation to ensure water quality does not degrade during project operation;

• Implement the Vegetation Management Plan filed with the license application that includes provisions for revegetating disturbed areas, wetland protection, and invasive weed control before, during, and after construction;

• Conduct a pre-construction survey for raptor nests and schedule construction activities or establish a 0.5-mile construction buffer, as appropriate, to minimize disturbance of nesting raptors;

• Design and construct the project transmission line in accordance with current avian protection guidelines, including installing flight diverters and perch deterrents to prevent collision and electrocution hazards and increased predation of upland sage grouse;

• Implement the Visual Resources Management Plan (VRMP) filed with the license application that includes measures to design and select materials to reduce the visual contrast of project facilities;

• Post signs and public notice, limit construction hours, days, and locations, and stage construction traffic to reduce conflicts with recreational users and other motorists;

• Implement the Buffalo Bridge Fishing Access Road Management Plan filed with the license application that includes provisions for flagging, traffic control devices, and public notice of construction activities to maintain traffic safety and minimize effects on fishing access;

• Install and maintain an interpretive sign near the dam that describes the concept and function of the hydroelectric project and how it affects the sport fisheries, including any measures taken to eliminate or reduce adverse effects;

• Use a single-pole design for the transmission line, along with materials and colors that reduce visibility and blend with the surroundings; and

• Implement the revised Historic Properties Management Plan (HPMP) filed February 9, 2016, and stop work if any unanticipated cultural materials or human remains are found.

Public Involvement and Areas of Concern

This project was previously licensed under a similar design as FERC Project No.12429 (P-12429) on August 26, 2009.

The license was amended on March 7, 2013, to alter the project transmission line from a 0.3-mile-long, 24.9-kV buried transmission line to a 7.9-mile-long, 69-kV overhead powerline.

That license was terminated on March 19, 2015, for failure to commence construction by the deadline established in section 13 of the FPA. Because of the similarity of the project features and level of consultation that occurred during the preparation of the current license application, the Commission waived the pre-filing, three-stage consultation process and scoping for this project by notice issued on December 4, 2015. On February 23, 2016, the Commission issued a notice stating that the application was accepted and ready for environmental analysis, setting March 24, 2016, as the deadline for filing protests and motions to intervene as well as comments, terms and conditions, recommendations, and prescriptions.

See

128 FERC ¶ 62,129 (2009).

See

142 FERC ¶ 62,192 (2013).

The primary issues associated with licensing the project are the protection of wetlands, water quality, fish and wildlife habitat, visual resources, and cultural resources during project construction and operation.

Alternatives Considered

This EA analyzes the effects of project construction and operation and recommends conditions for an original license for the project. The EA considers three alternatives: (1) the applicant's proposal, as outlined above; (2) the applicant's proposal with staff modifications (staff alternative); and (3) no action—no project construction or operation (no-action alternative).

Staff Alternative

Under the staff alternative, the project would be constructed and operated as proposed by the applicant with the modifications and additional measures described below. This alternative includes all of the mandatory conditions specified by Reclamation under section 4(e) of the Federal Power Act and all but one of the conditions specified by Montana Department of Environmental Quality's (Montana DEQ) section 401 Water Quality Certification (certification).

Our recommended modifications and additional environmental measures include, or are based on, recommendations made by federal and state resource agencies that have an interest in resources that may be affected by operation of the proposed project.

The staff alternative does not include condition 11 which stipulates that the applicant meet annually with all watershed stakeholders to discuss water quality monitoring efforts associated with project operation. However, we recognize that the Commission is required to include valid section 401 water quality certification conditions in any license issued for the project.

Under the staff alternative, the project would include most of the applicant's proposed measures, as outlined above, and the following additional measures: (1) TDG and DO compliance monitoring at all times during project operation rather than just potentially for the first five years of operation; (2) water temperature monitoring for the first five years of project operation and, after consultation with the agencies, filing a proposal for Commission approval regarding the possible cessation of temperature monitoring after the first five years; (3) installing and maintaining a pressure transducer and water level alarm in the Beaverhead River when flows are being bypassed around Reclamation's existing intake and outlet works to alert compliance monitoring staff if water levels downstream of the dam are reduced; (4) notifying Montana Department of Fish, Wildlife, and Parks (Montana DFWP) in addition to Reclamation in the event of an unplanned shutdown during project operation; (5) notifying Montana DEQ and Montana DFWP within 24 hours of any deviation from water temperature, DO, TDG, or turbidity requirements during construction and operation and filing a report with the Commission within 30 days describing the deviation, any adverse effects resulting from the deviation, the corrective actions taken, any proposed measures to avoid future deviations, and comments or correspondence, if any, received from the agencies; (6) maintaining records of pre-construction raptor surveys that includes presence of birds, eggs, and active nests, the qualifications of the biologist performing the survey, and measures implemented to avoid disturbing nesting birds; and (7) constructing the transmission line segments that cross the Horse Prairie and Medicine Lodge drainages outside of the greater sage-grouse breeding season (March 1-April 15); and (8) revising the HPMP in consultation with the Montana State Historic Preservation Officer (Montana SHPO) and Reclamation to include a Treatment Plan to resolve project effects on the Clark Canyon Dam and to clarify consultation procedures and filing the plan with the Commission for approval prior to construction.

Under the no-action alternative, the proposed project would not be built and environmental resources in the project area would not be affected.

Project Effects

Geology and Soils

Some unavoidable minor, short-term increases in turbidity would occur in the Beaverhead River downstream of the project during project construction. These effects would be minimized by implementing the applicant's ESCP.

Aquatic Resources

Operating the project in a run-of-release mode would protect aquatic habitat in the impoundment and in the Beaverhead River downstream of the project. Installing the penstock and associated valves would temporarily impair Reclamation's ability to release stream flows downstream of the dam.

However, pumping flows around Reclamations' existing intake and outlet works to the Beaverhead River as outlined in the applicant's Final Instream Flow Release Plan would ensure that streamflows and water quality are maintained downstream during this phase of construction. Also, the applicant's proposal to provide 24-hour attendance of the pumping system for the duration of pumping activities would ensure that any failure or malfunction of the pumping equipment could be dealt with in a timely manner to avoid downramping during the trout spawning season. Staff's recommendation to install a flow meter and water level alarm would detect falling water levels in the event of an equipment failure and alert construction staff of the need to activate backup pumps.

Current dam operations can cause total dissolved gases (TDG) levels to rise above 115 percent saturation, exceeding the state standard of 110 percent and potentially harming fish. Discharging flows through the project instead of Reclamation's outlet works would reduce the plunging effect and potential for entrained air to enter solution under pressure, thereby reducing the potential for TDG supersaturation which would be a project benefit. However, TDG supersaturation could still affect aquatic resources at times in the summer or early fall when flow release requirements exceed the hydraulic capacity of the project or when the project is shut down and flows exit at high pressure through the existing outlet works.

Reducing the turbulence from Reclamation's discharges could also reduce dissolved oxygen (DO) levels downstream. However, injecting air through the proposed aeration basin based on incoming DO levels and the level of aeration needed to maintain the state criteria of 7.5-8.0 mg/L as described in the applicant's Revised DOEP would maintain adequate DO levels in the project tailrace and potentially enhance DO levels in the summer months, which would benefit trout in the Beaverhead River. Deploying corrective measures and emergency shutdown procedures if DO falls below state criteria would further protect aquatic resources during low DO periods.

The applicant's proposal to monitor water temperature, DO, TDG, and turbidity prior to and during construction as described in its CWQMP and its proposal to monitor water temperature, DO, and TDG for a minimum of the first five years of project operation as described in its Revised DOEP would allow the applicant to document and report compliance with state water quality criteria and would inform the need for corrective measures to protect water quality during the monitoring period. Staff's recommendation that the applicant extend monitoring for DO and TDG for the term of any license issued would ensure that the aeration basin continues to function properly and maintains or improves water quality downstream. Staff's recommended reporting requirements during construction and operation would facilitate the Commission's administration of the license and ensure that any appropriate corrective measures to protect water quality are timely identified and implemented.

The applicant's proposal to screen the pump intakes would limit the potential for entrainment of fish during project construction. However, some fish are likely to be entrained and injured as they pass through the project turbines during operation similar to existing conditions.

Terrestrial Resources

Project construction would temporarily disturb and displace some wildlife and would permanent remove 0.10 acres of vegetation. Implementing the best management practices in the applicant's proposed VMP would protect wetlands and prevent the introduction and spread of noxious weeds during construction.

Vegetation lost during construction of the transmission line right-of-way and staging and spoil areas would be restored following construction using native plant species approved by Reclamation and BLM which would provide locally-adapted and naturally-occurring habitat and forage for wildlife.

The potential for avian electrocutions and collisions with the transmission line would be reduced by the applicant's proposals to design the transmission line in adherence to current avian protection standards, including installing flight diverters and perch deterrents on the power line. Perch deterrents would also discourage predators from perching on the transmission line poles, which would protect greater sage-grouse. Restricting construction within 0.5 miles of a raptor nests would avoid disturbing or displacing nesting raptors.

Threatened and Endangered Species

Project construction and operation would not affect the federally listed threatened Ute ladies'-tresses, the threatened grizzly bear, or the threatened Canada lynx because the project area does not contain suitable habitat for either species, or for the snowshoe hare, which is the primary prey of the Canada lynx. There is no designated critical habitat within the project area for these species.

Cultural Resources

Clark Canyon Dam and six other cultural resource sites along the transmission corridor were identified during site investigations. Project construction would only affect the Clark Canyon Dam, which was determined to be eligible for listing on the National Register of Historic Places. The Montana SHPO concurred with these findings.

Revising the HPMP to include a Treatment Plan to resolve project effects on the Clark Canyon Dam and to clarify consultation procedures for addressing any future maintenance activities would protect known and any newly discovered historic properties.

See

the Programmatic Agreement issued by the Commission on May 5, 2016, and the letter from the Montana SHPO to the Commission, filed March 25, 2016.

Recreation, Land Use, and Aesthetics

Clark Canyon Reservoir and the Beaverhead River are popular recreational destinations, particularly for fishing, boating, and camping. The noise and dust associated with construction activities could disturb recreationists, and safety concerns could arise where recreational users and construction vehicles use the same roadways to access areas near the dam or transmission line. The applicant's proposed Buffalo Bridge Fishing Access Road Management Plan would reduce the effects of construction traffic on recreation users at that location. The applicant's proposed limits on construction hours and days, along with public notice of construction activities would help to minimize conflicts with recreational users, and its proposed signing, flagging, barriers, and construction traffic staging would minimize conflicts with other motorists. During project operation, minor noise and light from the powerhouse could be noticeable to recreation users nearby, particularly below the dam.

Installing and maintaining an interpretive sign at the Clark Canyon Dam Fishing Access site would inform visitors of the concept and function of the hydroelectric project, how it affects the sport fisheries, and any measures taken to eliminate or reduce adverse effects.

Construction of the powerhouse, transmission line, and construction and access roads would introduce new visual elements to the existing

environment. Implementing the applicants proposed Visual Resources Management Plan would ensure that project design incorporates the use of color, form, grading, and revegetation that would minimize the project's long-term visual contrast with the existing environment. The overhead transmission line would be designed and located to further minimize visual effects on scenic vistas and nearby recreational use.

Under the no-action alternative, the project would not be constructed and the environmental resources in the project areas would not be affected.

Conclusions

Based on our analysis, we recommend licensing the project as proposed by the applicant with staff modifications and additional measures, as described above under

Alternatives Considered.

In section 4.2 of the EA, we estimate the likely cost of alternative power for each of the two alternatives identified above. Our analysis shows that during the first year of operation under the applicant's proposal, project power would cost $2,331,512, or $151.40/MWh, more than the likely alternative cost of power. Under the staff alternative, project power would cost $2,335,362, or $151.65/MWh, more than the likely alternative cost of power.

We chose the staff alternative as the preferred alternative because: (1) the 4.7-MW project would save the equivalent amount of fossil-fueled generation and capacity, thereby helping to conserve non-renewable energy resources and reduce atmospheric pollution; and (2) the recommended environmental measures proposed by the applicant, as modified by staff, would adequately protect and enhance environmental resources affected by the project. The overall benefits of the staff alternative would be worth the cost of the proposed and recommended environmental measures.

We conclude that issuing a license for the project, with the environmental measures that we recommend, would not be a major federal action significantly affecting the quality of the human environment.

Environmental Assessment

Federal Energy Regulatory Commission, Office of Energy Projects, Division of Hydropower Licensing, Washington, DC

Clark Canyon Dam Hydroelectric Project

FERC Project No. 14677-001—Montana

Month XX, 2016

1.0 INTRODUCTION

1.1 Application

On November 23, 2015, Clark Canyon Hydro, LLC (applicant) filed an application for an original license to construct, operate, and maintain the Clark Canyon Dam Hydroelectric Project (project). The 4.7-megawatt (MW) project would be located at the U.S. Bureau of Reclamation's (Reclamation's) Clark Canyon Dam on the Beaverhead River, near the city of Dillon, Montana (figure 1). The proposed project would occupy 62.1 acres of federal lands within the Pick-Sloan Missouri Basin Program, East Bench Unit, administered by Reclamation, and 0.2 acres of land administered by the U.S. Bureau of Land Management. The project would generate an average of about 15,400 megawatt-hours (MWh) of energy annually.

1.2 Purpose of Action and Need For Power

1.2.1 Purpose of Action

The Federal Energy Regulatory Commission (Commission or FERC) must decide whether to issue a license to the applicant for the project and what conditions should be placed in any license issued. In deciding whether to issue a license for a hydroelectric project, the Commission must determine that the project will be best adapted to a comprehensive plan for improving or developing a waterway. In addition to the power and developmental purposes for which licenses are issued (

e.g.,

flood control, irrigation, and water supply), the Commission must give equal consideration to the purposes of energy conservation, the protection, mitigation of damage to, and enhancement of fish and wildlife (including related spawning grounds and habitat), the protection of recreational opportunities, and the preservation of other aspects of environmental quality.

Issuing a license for the project would allow the applicant to generate electricity at the project for the term of an original license, making electric power from a renewable resource available to the public.

BILLING CODE 6717-01-P

EN29JN16.001

BILLING CODE 6717-01-C

This environmental assessment (EA) assesses the environmental and economic effects of constructing and operating the proposed hydroelectric project: (1) As proposed by the applicant, and (2) with our recommended measures and agency mandatory conditions. We also consider the effects of the no-action alternative. Important issues that are addressed include the protection of wetlands, water quality, fish and wildlife habitat, visual resources, and cultural resources during project construction and operation.

1.2.2 Need for Power

The project would provide hydroelectric generation to meet part of Montana's power requirements, resource diversity, and capacity needs. The project would have an installed capacity of 4.7 MW and generate approximately 15,400 MWh per year.

The North American Electric Reliability Corporation (NERC) annually forecasts electric supply and demand nationally and regionally for a 10-year period. The proposed project would be located in the Northwest Power Pool area of the Western Electricity Coordinating Council (WECC) region of NERC. For the 2016-2025 time period, NERC projects that total demand for the summer, the peak season for the entire WECC Region, decreased by 2.3 percent due to generally mild temperatures and increased distributed solar generation. The demand for the summer season is projected to increase by 1.1% per year, while the annual energy load is projected to increase by 1.2% per year for the same time period.

We conclude that power from the proposed project would help meet a need for power in the WECC region in both the short and long term. The project would provide power that would displace non-renewable, fossil-fired generation and contribute to a diversified generation mix. Displacing the operation of fossil-fueled facilities avoids some power plant emissions and creates an environmental benefit.

1.3 Statutory and Regulatory Requirements

A license for the project is subject to numerous requirements under the Federal Power Act (FPA) and other applicable statutes. The major regulatory and statutory requirements are summarized in table 1 and described below.

Table 1—Major statutory and Regulatory Requirements for the Clark Canyon Dam Hydroelectric Project

[Source: Staff]

Requirement

Agency

Status

Section 18 of the FPA (fishway prescriptions)

FWS

No fishway prescription or requests for reservation of authority to prescribe fishways were filed.

Section 4(e) of the FPA (land management conditions)

Reclamation

Interior, on behalf of Reclamation, filed preliminary conditions on March 17, 2016.

Section 10(j) of the FPA

FWS

Interior, on behalf of FWS, filed section 10(j) recommendations on March 17, 2016.

Montana DFWP

No section 10(j) recommendations were filed.

Endangered Species Act consultation

FWS

Commission staff generated official species list from FWS's IPaC website on April 15, 2016.

Clean Water Act—section 401 water quality certification

Montana DEQ

Applicant submitted an application for certification on April 15, 2016, which was received by Montana DEQ on April 18, 2016. Montana DEQ issued a draft certification for public comment on June 3, 2016; comments are due to Montana DEQ by July 5, 2016. Certification is due by April 18, 2017.

National Historic Preservation Act

Montana SHPO

The Clark Canyon Dam was determined to be eligible for listing on the National Register of Historic Places. A PA was signed by the SHPO and filed on May 31, 2016, requiring the applicant to revise its HPMP and prepare a Treatment Plan to resolve effects.

Notes:

Commission—Federal Energy Regulatory Commission. FPA—Federal Power Act. FWS—U.S. Fish and Wildlife Service. HPMP—Historic Properties Management Plan. Interior—U.S. Department of the Interior. Montana DEQ—Montana Department of Environmental Quality. Montana DFWP—Montana Department of Fish, Wildlife and Parks. Montana SHPO—Montana State Historic Preservation Officer. PA—Programmatic Agreement. Reclamation—U.S. Bureau of Reclamation.

1.3.1 Federal Power Act

1.3.1.1 Section 18 Fishway Prescription

Section 18 of the FPA states that the Commission is to require construction, operation, and maintenance by a licensee of such fishways as may be prescribed by the Secretaries of the U.S. Department of Commerce (Commerce) or the U.S. Department of the Interior (Interior). Neither Commerce nor Interior filed a fishway prescription or requested a reservation of authority to prescribe fishways at the project.

1.3.1.2 Section 4(e) Conditions

Section 4(e) of the FPA provides that any license issued by the Commission for a project within a federal reservation shall be subject to and contain such conditions as the Secretary of the responsible federal land management agency deems necessary for the adequate protection and use of the reservation. Interior, on behalf of Reclamation, filed preliminary conditions on March 17, 2016, pursuant to section 4(e) of the FPA. These conditions are described under section 2.2.5,

Modifications to Applicant's Proposal—Mandatory Conditions.

1.3.1.3 Section 10(j) Recommendations

Under section 10(j) of the FPA, each hydroelectric license issued by the Commission must include conditions based on recommendations provided by federal and state fish and wildlife agencies for the protection, mitigation, or enhancement of fish and wildlife resources affected by the project. The Commission is required to include these conditions unless it determines that they are inconsistent with the purposes and requirements of the FPA or other applicable law. Before rejecting or modifying an agency recommendation, the Commission is required to attempt

to resolve any such inconsistency with the agency, giving due weight to the recommendations, expertise, and statutory responsibilities of such agency.

On March 17, 2016, Interior, on behalf of the U.S. Fish and Wildlife Service (FWS), timely filed recommendations under section 10(j), as summarized in table 7 in section 5.4.1,

Recommendations of Fish and Wildlife Agencies.

In section 5.4,

Summary of Section 10(j) Recommendations and 4(e) Conditions,

we discuss how we address the agency recommendations and comply with section 10(j).

1.3.2 Clean Water Act

Under section 401 of the Clean Water Act (CWA), a license applicant must obtain certification from the appropriate state pollution control agency verifying compliance with the CWA. On April 15, 2016, the applicant applied to the Montana Department of Environmental Quality (Montana DEQ) for 401 water quality certification (certification) for the Clark Canyon Dam Hydroelectric Project. Montana DEQ acknowledged receipt of the application on April 18, 2016.

Montana DEQ issued a draft certification for a 30-day public comment period on June 3, 2016; comments are due to Montana DEQ by July 5, 2016. Clark Canyon Hydro filed the draft certification with the Commission on June 7, 2016. The certification is due by April 18, 2017.

The letter confirming receipt was dated April 18, 2016, and filed with the Commission the following day.

1.3.3 Endangered Species Act

Section 7 of the Endangered Species Act (ESA) requires federal agencies to ensure that their actions are not likely to jeopardize the continued existence of endangered or threatened species or result in the destruction or adverse modifications of the critical habitat of such species. No federally listed species are known to occur within the project area; however, on April 15, 2016, Commission staff generated an official species list on FWS's Information, Planning, and Conservation (IPaC) Web site that indicates that three threatened species: The Ute ladies'-tresses (

Spiranthes diluvialis

), the grizzly bear (

Ursus arctos horribilis

), and the Canada lynx (

Lynx canadensis

) may occur in the project area. There are no critical habitats in the project area for these species. See section 3.3.4,

Threatened and Endangered Species,

for our analysis of the occurrence of listed species and the potential for effects on them. We conclude that the proposed action would have no effect on the threatened Ute ladies'-tresses, threatened grizzly bear, or the threatened Canada lynx.

1.3.4 National Historic Preservation Act

Section 106 of the National Historic Preservation Act of 1966 (NHPA) as amended requires that every federal agency “take into account” how the agency's undertakings could affect historic properties. Historic properties are districts, sites, buildings, structures, traditional cultural properties (TCPs), and objects significant in American history, architecture, engineering, and culture that are eligible for inclusion in the National Register of Historic Places (National Register).

The Clark Canyon Dam was determined to be individually eligible for listing on the National Register and would be adversely affected by project construction; six other sites located along the transmission line corridor that may or may not be eligible would not be adversely affected by project construction and operation. Commission staff and the Montana SHPO concurred with these findings as discussed in a letter and Programmatic Agreement (PA) issued on May 5, 2016. The SHPO signed the PA and filed it on May 31, 2016. In the event that a license is issued for the project, the PA requires the licensee to revise its proposed HPMP

to include a Treatment Plan to resolve effects on the dam, as well as address other concerns raised by the SHPO and Reclamation with regard to future consultation and review of ongoing activities at the dam (as discussed in section 3.3.6,

Cultural Resources

). The Treatment Plan and revised HPMP would be developed by the licensee in consultation with the SHPO and Reclamation, and would be filed with the Commission for approval prior to construction. Additionally, the Commission contacted the Shoshone-Bannock, Eastern Shoshone, Nez Perce, and Salish-Kootenai tribes inviting comments and consultation. No comments or requests for consultation were received from the tribes.

The HPMP filed with the license application was developed by the applicant before the Clark Canyon Dam was determined to be eligible for listing on the National Register. A modified HPMP filed by the applicant on February 9, 2016, acknowledges eligibility and adverse effects on the dam, but does not resolve the effects.

1.4 Public Review and Consultation

The Commission's regulations (18 Code of Federal Regulations [CFR], section 4.38) require that applicants consult with appropriate resource agencies, tribes, and other entities before filing an application for a license. This consultation is the first step in complying with the Fish and Wildlife Coordination Act, the ESA, the NHPA, and other federal statutes. Pre-filing consultation must be complete and documented according to the Commission's regulations.

In its tendering notice issued December 4, 2015, the Commission stated its intent to waive the three-stage pre-filing consultation process and scoping for this project based on the pre-filing consultation record. No objections were filed.

1.4.1 Interventions

On February 23, 2016, the Commission issued a notice stating that the applicant's application was accepted and ready for analysis. This notice set March 24, 2016, as the deadline for filing protests and motions to intervene. On March 22, 2016, Upper Missouri Waterkeeper filed a motion to intervene.

1.4.2 Comments on the License Application

The February 23, 2016, notice solicited comments, terms and conditions, recommendations, and prescriptions. In a letter filed March 17, 2016, Interior, on behalf of Reclamation and FWS, filed preliminary comments, terms and conditions, recommendations, and prescriptions. The following entities commented:

Commenting agencies and other entities

Date filed

Wade Fellin

February 26, 2016.

Brian Wheeler

March 1, 2016.

Michael Stack

March 8, 2016.

Tim Hunt

March 11, 2016.

Steve Hemkens

March 14, 2016.

Kimball Leighton

March 17, 2016.

Department of the Interior

March 17, 2016.

Gregg B. Messel

March 21, 2016.

Woody Bailey

March 21, 2016.

Montana Department of Fish, Wildlife & Parks

March 24, 2016.

Rhonda Sellers (on behalf of International Federation of Fly Fishers)

March 24, 2016.

Luke Massaro

March 24, 2016.

Christian Appel

March 24, 2016.

Cordell Appel

March 24, 2016.

Upper Missouri Waterkeeper

March 24, 2016.

Montana Historical Society

March 25, 2016.

Montana Trout Unlimited

March 25, 2016.

The applicant filed reply comments on April 8, 2016.

Upper Missouri Waterkeeper also filed a form letter signed by 178 citizens urging the Commission to consider how the project may contribute to recent poor water quality conditions in the Beaverhead River.

2.0 PROPOSED ACTION AND ALTERNATIVES

2.1 No-Action Alternative

The no-action alternative is license denial. Under the no-action alternative, the proposed project would not be built and environmental resources in the project area would not be affected.

2.2 Applicant's Proposal

2.2.1 Proposed Project Facilities

Reclamation's Clark Canyon Dam and Reservoir are existing flood control and water conservation facilities at the head of the Beaverhead River in southwestern Montana, about 20 miles southwest of Dillon, Montana. Clark Canyon Dam was completed in 1964 for Reclamation's Pick-Sloan Missouri River Basin Program, East Bench Unit, which was authorized as part of the Flood Control Acts of 1944 and 1946.

The dam is a zoned, earth-fill structure that is approximately 2,950 feet long at the crest. The crest of the dam is at elevation 5,578 feet mean sea level (msl), with a structural height of 147.5 feet and width of 36 feet. The outlet works include an approach channel, an intake structure, a concrete conduit, a shaft house, and a 9-foot-diameter conduit that discharges into a stilling basin. The outlet works contain a gate chamber with four 3-foot by 6.5-foot high pressure gates. The discharge capacity of the outlet works is 2,325 cubic feet per second (cfs) at a reservoir water surface elevation of 5,547 feet msl. In addition, there is a separate uncontrolled spillway with a crest elevation of 5,571.9 feet msl, and a design discharge of 9,520 cfs.

The proposed project (figure 2) would use the existing dam, reservoir, and outlet works, and would consist of the following new facilities: (1) A 360-foot-long, 8-foot-diameter steel penstock within Reclamation's existing concrete conduit, ending in a trifurcation; (2) two 35-foot-long, 8-foot-diameter steel penstocks equipped with isolation valves extending from the trifurcation to the powerhouse, each penstock transitioning to 6-foot-diameter before entering the powerhouse; (3) a 10-foot-long, 8-foot-diameter steel penstock leaving the trifurcation and ending in a 7-foot-diameter cone valve and reducer to control discharge into Reclamation's existing outlet stilling basin; (4) a 65-foot-long, 46-foot-wide reinforced concrete powerhouse, located at the toe of the dam adjacent to the spillway stilling basin, containing two vertical Francis-type turbine/generator units with a total capacity of 4.7 MW; (5) two 25-foot-long steel draft tubes transitioning to a concrete draft tube/tailrace section; (6) a 17-foot-long, 15-foot-wide tailrace channel connecting with Reclamation's existing spillway stilling basin; (7) an aeration basin downstream of the powerhouse with three 45-foot-long, 10-foot-wide frames containing 330 diffusers; (8) a 4.16-kilovolt (kV) buried transmission line from the powerhouse to a substation containing step-up transformers and switchgear located 1,100 feet downstream of the powerhouse; (9) a 500-foot-long access road connecting to the existing access road; (10) a 7.9-mile-long, 69-kV overhead transmission line extending from the substation to the Peterson Flat substation (the point of interconnection); and (11) appurtenant facilities.

2.2.2 Proposed Project Boundary

The proposed project boundary

will enclose: 4.3 acres around the outlet conduit, penstock, powerhouse, aeration basin, tailrace, and valve house; 1.9 acres of staging area; 2.5 acres along proposed and existing access roads; and 0.4 acres along the transmission line corridor, for a total of about 12.7 acres of federal lands under jurisdiction of Reclamation's Pick-Sloan Missouri Basin Program, East Bench Unit.

Upper Missouri Waterkeeper's recommends that the existing Clark Canyon Dam and Reservoir be included in the project boundary. However, since the dam was constructed and is operated by Reclamation for flood control and water conservation purposes, the applicant will have no control over the dam or reservoir. The dam and reservoir would not be project features to be included in the project boundary.

BILLING CODE 6717-01-P

EN29JN16.002

BILLING CODE 6717-01-C

2.2.2 Project Safety

As part of the licensing process, the Commission would review the adequacy of the proposed project facilities. Special articles would be included in any license issued, as appropriate. Commission staff would inspect the licensed project both during and after construction. Inspection during construction would concentrate on adherence to Commission-approved plans and specifications, special license articles relating to construction, and accepted engineering practices and procedures. Operational inspections would focus on the continued safety of the structures, identification of unauthorized modifications, efficiency and safety of operation, compliance with the terms of the license, and proper maintenance. Additionally, Reclamation's preliminary section 4(e) conditions require Reclamation review and approval of plans and specifications to ensure structural adequacy and compatibility of the proposed projects with the authorized purposes of Reclamation's East Bench Unit. Any license issued would give Reclamation oversight over construction, operation, and maintenance of the project as they pertain to the structural integrity or operation of the East Bench Unit. Construction, operation, and maintenance of project works that may affect the structural integrity or operation of the East Bench Unit would also be subject to periodic or continuous inspections by Reclamation.

2.2.3 Proposed Project Operation

The Clark Canyon Dam and Reservoir are owned and operated by Reclamation for irrigation storage, flood control, and recreational opportunities. Reclamation's existing facilities are not currently capable of providing hydroelectric power generation. Regulation of the reservoir and corresponding water releases are made in accordance with standard procedures developed by Reclamation. The East Bench Irrigation District (District) is responsible for operation of the dam and reservoir in close coordination with Reclamation. Operation of the dam and reservoir would not be altered to accommodate operation of the proposed hydroelectric facilities. The proposed project would use water that is currently released from the reservoir into the Beaverhead River through the existing intake structure and outlet works on the dam.

The proposed hydropower project would require no modification to existing Clark Canyon Dam and Reservoir uses and would operate in a run-of-release mode with no daily storage, using normally released flows to produce power. The hydropower project would have the ability to be operated automatically, but an operator would be on site daily for operation. Power generation would be seasonally dictated as flow regimes, reservoir levels, and so on are set forth by Reclamation.

The project would operate using Reclamation's flow releases ranging from 87.5 to 700 cfs (minimum capacity of 87.5 cfs and a maximum capacity of 350 cfs per unit totaling 700 cfs). Flows less than the 87.5-cfs would cause the isolation valve in the penstock to close, allowing all flows to bypass the powerhouse and flow through the existing outlet works into the stilling basin. When the project is operating at maximum capacity, flows in excess of 700 cfs would continue to flow through Reclamation's existing outlet works and over its spillway into the stilling basin.

The proposed project would have an installed generating capacity of 4.7 MW, with an average annual generation of 15,400 MWh.

2.2.4 Proposed Environmental Measures

The applicant proposes the following environmental measures:

• Implement the Erosion and Sediment Control Plan (ESCP) filed with the license application to minimize soil erosion and dust, protect water quality, and minimize turbidity in the Beaverhead River;

• Implement the Instream Flow Release Plan filed with the license application with provisions to temporarily pump bypassed flows around Reclamation's existing intake and outlet works to prevent interrupting Reclamation's flow releases into the Beaverhead River during installation of the proposed project's penstock;

• Maintain qualified compliance monitoring staff on site 24 hours per day and 7 days per week when flows are bypassing Reclamation's outlet works to ensure staff promptly responds to a pumping equipment failure or malfunction and ensure Reclamation's flow releases are maintained in the Beaverhead River downstream;

• Implement the Revised Dissolved Oxygen Enhancement Plan (Revised DOEP) filed with the license application that includes installing and operating an aeration basin to increase DO levels of water exiting the powerhouse and monitoring and reporting water temperature, DO, and TDG levels for a minimum of the first five years of project operation to ensure water quality does not degrade during project operation;

• Conduct a pre-construction survey for raptor nests and schedule construction activities or establish a 0.5-mile construction buffer as appropriate to minimize disturbing nesting raptors;

• Design and construct the project transmission line in accordance with current avian protection guidelines, including installing flight diverters and perch deterrents;

• Post signs and public notice, limit construction hours, days, and locations, and stage construction traffic to reduce conflicts with recreational users and other motorists;

• Implement the Buffalo Bridge Fishing Access Road Management Plan filed with the license application, including provisions for flagging, traffic control devices, and public notice of construction activities to maintain traffic safety and minimize effects on fishing access;

• Use a single-pole design for the transmission line, along with materials and colors that reduce visibility and blend with the surroundings; and

• Implement the revised Historic Properties Management Plan (HPMP) filed February 9, 2016. Stop work if any unanticipated cultural materials or human remains are found.

2.2.5 Modifications to Applicant's Proposal—Mandatory Conditions

2.2.5.1 Section 4(e) Land Management Conditions

Interior, on behalf of Reclamation, filed nine mandatory conditions under FPA section 4(e). Conditions 1 through 3 and conditions 5 through 9 are administrative conditions that would require the applicant to enter into a construction, operation, and maintenance agreement with Reclamation; consult with and receive

approval from Reclamation for those facilities that would be an integral part of, or could affect the structural integrity or operation of, the federal reservation; not impair the structural integrity or operation of the federal facilities or the federal government's ability to fulfill its trust responsibilities to Indian tribes; have no claim against the United States arising from any change in operation of the federal facility; recognize the primary right of any Reclamation activity or the fulfillment of Indian water rights taking precedence over project hydropower activities; provide to the Commission's Regional Engineer copies of all correspondence between the licensee and Reclamation; provide Reclamation the opportunity to review and approve the design of contractor-designed cofferdams, blasting, and deep excavations; and acknowledge that the timing, quantity, and location of water releases and release changes from the facilities would be at the sole discretion of Reclamation. Condition 4 requires the applicant to revegetate all newly disturbed land areas with plant species indigenous to the area within 6 months of the completion of the project's construction.

2.2.5.2 Water Quality Certification Conditions

Montana DEQ's certification includes 13 conditions. Conditions 1 through 7 and condition 11 are environmental measures that are evaluated in the EA. Conditions 8 through 10 and conditions 12 and 13 are administrative or legal in nature and not environmental measures; therefore we do not analyze them in the EA.

The administrative measures specify that Clark Canyon Hydro: Allow Montana DEQ reasonable entry and access to the project and review of appropriate records; obtain all required permits, authorizations, and certifications prior to commencement of any activity that would violate Montana water quality standards; understand that Montana DEQ's reserves its authority to require adaptive management plans that may include corrective actions and monitoring necessary to correct water quality violations that may result from construction or operation; consider the terms and conditions of the certification to be violated if the project is found to not be in compliance with any of the certification conditions or if the project is constructed or operated in any way not specified in the application, supporting documents or as modified by the conditions; and understand that the certification expires upon transfer of property covered by the certification unless the new owner submits to Montana DEQ a written consent to all the certification conditions.

Environmental measures included in Montana DEQ's certification conditions 1 through 7 and condition 11 that are analyzed in this EA are as follows:

• Condition 1 stipulates that Clark Canyon Hydro conduct water quality monitoring for DO, temperature, and TDG for a minimum of five years following initial project operation and to continue monitoring these parameters each year thereafter while discharging between July and October, unless Montana DEQ determines that additional monitoring is not warranted upon review of the five-year monitoring results.

• Condition 2 stipulates that Clark Canyon Hydro submit a plan prior to construction to monitor Clark Canyon Reservoir and the Beaverhead River for turbidity, TDG, DO, and temperature during project construction.

Montana DEQ clarified in a phone conversation with staff that condition 2 refers directly to the applicant's CWQMP filed with the license application and would not require a new or modified plan to be submitted.

See

telephone record summary between FERC and Montana DEQ filed on June 9, 2016.

• Condition 3 stipulates that Clark Canyon Hydro maintain minimum DO levels at saturation from June 1 through August 31 and 8.0 milligrams per liter (mg/L) the rest of the year downstream of the project while discharging into the Beaverhead River.

• Condition 4 stipulates that Clark Canyon Hydro maintain TDG levels at 110 percent or lower downstream of the project while discharging into the Beaverhead River.

• Condition 5 stipulates that Clark Canyon Hydro submit a plan prior to construction for project engineering modifications to maintain DO levels during project operation.

Montana DEQ clarified in a phone conversation with staff that condition 5 refers directly to the applicant's Revised DOEP filed with the license application and would not require a new or modified plan to be submitted.

See

telephone record summary between FERC and Montana DEQ filed on June 9, 2016.

• Condition 6 stipulates that the project automatically go offline in the event that DO levels fall below Montana DEQ standards, that an on-call operator arrive at the powerhouse within 30 minutes to evaluate the cause of any noncompliance reading, and that Clark Canyon Hydro deploy a redundant DO probe at its compliance point in the Beaverhead River.

• Condition 7 stipulates that Clark Canyon Hydro notify Montana DFWP and Montana DEQ within 24 hours of any unauthorized discharge of pollutants to state waters within the project boundary.

• Condition 11 stipulates that Clark Canyon Hydro meet annually with all watershed stakeholders to discuss water quality monitoring efforts associated with project operation.

2.3 Staff Alternative

Under the staff alternative, the project would include all of the applicant's proposals, all of Reclamation's conditions specified under FPA section 4(e), all but one of Montana DEQ's certification conditions,

and the following additional measures:

The staff alternative does not include condition 11 which stipulates that the applicant meet annually with watershed stakeholders to discuss water quality monitoring efforts associated with project operation. However, we recognize that the Commission is required to include all valid 401 water quality certification conditions in any license issued for the project.

• Conduct TDG and DO compliance monitoring at all times during project operation;

• Conduct water temperature monitoring for the first five years of project operation and, after consultation with Montana DFWP, Montana DEQ, and FWS, file a proposal for Commission approval regarding the possible cessation of the temperature monitoring program after 5 years;

• Install and maintain a pressure transducer and water level alarm in the Beaverhead River when flows are being bypassed around Reclamation's existing intake and outlet works to alert compliance monitoring staff if water levels downstream of the dam are reduced;

• During project operation, notify Montana DFWP in addition to Reclamation in the event of an unplanned shutdown;

• Notify Montana DEQ and Montana DFWP, within 24 hours of any deviation from water temperature, DO, TDG, or turbidity requirements during construction and operation and file a report with the Commission within 30 days describing the deviation, any adverse effects resulting from the deviation, the corrective actions taken, any proposed measures to avoid future deviations, and comments or correspondence, if any, received from the agencies;

• Document the results of the pre-construction raptor survey and the measures taken to avoid disturbing raptors by maintaining a record that includes nesting bird survey data, including the presence of migratory birds, eggs, and active nests, the qualifications of the biologist performing the survey, and any avoidance measures implemented;

• Construct the transmission line segments that cross the Horse Prairie

and Medicine Lodge drainages outside of the greater sage-grouse breeding season (March 1-April 15); and

• Revise the Historic Properties Management Plan (HPMP) in consultation with the Montana SHPO and Reclamation to include a Treatment Plan to resolve project effects on the Clark Canyon Dam and to clarify consultation procedures in the plan (see section 3.3.6). File the HPMP with the Commission for approval prior to construction.

Proposed and recommended measures are discussed under the appropriate resource sections and summarized in section 4 of this EA.

3.0 ENVIRONMENTAL ANALYSIS

In this section, we present: (1) A general description of the project vicinity; (2) an explanation of the scope of our cumulative effects analysis; and (3) our analysis of the proposed action and other recommended environmental measures. Sections are organized by resource area (

e.g.,

aquatic resources, recreation). Under each resource area, historical and current conditions are first described. The existing condition is the baseline against which the environmental effects of the proposed action and alternatives are compared, including an assessment of the effects of proposed mitigation, protection, and enhancement measures, and any potential cumulative effects of the proposed action and alternatives. Staff conclusions and recommended measures are discussed in section 5.2,

Comprehensive Development and Recommended Alternative.

Unless noted otherwise, the sources of our information are the final License Application filed on November 23, 2015 (Clark Canyon Hydro, LLC, 2015a) and additional information filed on December 10, 2015 (Clark Canyon Hydro, LLC, 2015), February 1, 2016 (Clark Canyon Hydro, LLC, 2016b), February 9, 2016 (Clark Canyon Hydro, LLC, 2016a), and March 11, 2016 (Clark Canyon Hydro, LLC, 2016).

3.1 General Description of the River Basin

The Beaverhead River is formed by the confluence of the Red Rock River and Horse Prairie Creek immediately upstream of Clark Canyon Dam. Other important tributaries include Cedar Creek, Medicine Lodge Creek, and Maurer Creek upstream of the dam, and Gallagher Creek and Grasshopper Creek downstream of the dam. From its origin at the tailrace of Clark Canyon Dam, the river flows approximately 71 miles to its confluence with the Big Hole River at Twin Bridges, Montana, where it forms the Jefferson River. The Jefferson River merges with the Madison and Gallatin rivers at Three Forks, Montana, about 100 miles downstream of Clark Canyon Dam, to form the Missouri River.

The topography of the Beaverhead River Basin is characterized by arid hillsides throughout the first 12 river miles (RM), opening into a wide valley about 8 miles south of Dillon, Montana. The total drainage area encompasses 3,619 square miles. Average annual precipitation in the basin is largely dependent on location and elevation. The southeast and western portions of the basin receive up to 20 inches. At the city of Dillon, about 20 miles from Clark Canyon Dam, the average annual precipitation is 11.7 inches. Winter and summer temperatures average about 26 and 63 degrees Fahrenheit (°F), respectively, at Dillon.

Clark Canyon Reservoir and the Beaverhead River provide water for Reclamation's East Bench Unit of the Pick-Sloan Missouri Basin Irrigation Program. The program provides full irrigation services for up to 28,055 acres of land to support the agricultural industry.

3.2 Scope of Cumulative Effects

According to the Council on Environmental Quality's regulations for implementing the National Environmental Policy Act (40 CFR, section 1508.7), cumulative effect is the impact on the environment that results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency (federal or non-federal) or person undertakes such other actions. Cumulative impacts can result from individually minor but collectively significant actions taking place over a period of time, including hydropower and other land and water development activities.

Based on our review of the license application and agency and public comments, we have identified aquatic resources, including fisheries and water quality, as resources that may be cumulatively affected by the project in combination with other past, present, and future activities, because of the potential for the project to adversely affect aquatic habitat and water quality, which are affected by upstream land uses and water storage and diversion.

3.2.1 Geographic Scope

The geographic scope of the analysis defines the physical limits or boundaries of the proposed action's effects on the resources. Because the proposed action would affect these resources differently, the geographic scope for each resource varies.

We have determined that the geographic scope for cumulatively affected fishery resources would encompass the Beaverhead River from Clark Canyon Dam to Barrett's Diversion Dam, located about 11 miles downstream. We chose this geographic scope because construction and operation of the project may affect streamflows and aquatic habitat in this reach.

For water quality, we have determined that the geographic scope would encompass Clark Canyon Reservoir, its two primary tributaries (Red Rock River and Horse Prairie Creek), and the Beaverhead River from Clark Canyon Dam downstream to Barrett's Diversion Dam. We chose this geographic scope because these stream reaches are on the CWA section 303(d) list as being impaired for water quality, and actions within these waterbodies together with construction and operation of the project may affect water quality in the Beaverhead River.

3.2.2 Temporal Scope

The temporal scope of analysis includes a discussion of the past, present, and reasonably foreseeable future actions and their effects on fishery and water quality resources. Based on the term of the proposed license, we will look 30 to 50 years into the future, concentrating on the effects on fish, fish habitat, and water quality from reasonably foreseeable future actions. The historical discussion is limited, by necessity, to the amount of available information. We identified the present resource conditions based on the license application, agency comments, and comprehensive plans.

3.3 Proposed Action and Action Alternatives

In this section, we discuss the effects of the project alternatives on environmental resources. For each resource, we first describe the affected environment, which is the existing condition and baseline against which we measure effects. We then discuss and analyze the specific cumulative and site-specific environmental issues.

Only the resources that would be affected, or about which comments have been received, are addressed in detail in this EA. Based on this, we have determined that geology and soils, fishery, water quality and quantity, terrestrial, threatened and endangered species, recreation, cultural, and aesthetic resources may be affected by the proposed action and action alternatives. We have not identified any substantive issues related to socioeconomics associated with the

proposed action, and therefore, socioeconomics is not assessed in this EA. We present our recommendations in section 5.2,

Comprehensive Development and Recommended Alternative.

3.3.1 Geologic and Soil Resources

3.3.3.1 Affected Environment

Clark Canyon Dam is located at the confluence of the Red Rock River and Horse Prairie Creek, where the watercourses become the Beaverhead River. The terrain in the area is generally characterized as arid rolling hills with watercourses carving floodplains and canyons into volcanic rock. In areas where the canyon sides become unstable as a result of erosion or seismic activity, landslides do occur and some affect the path of river flow.

Downstream of the dam, the river valley is relatively deep and narrow for about 12 miles, with an average gradient of 0.244 percent. The valley widens as the river crosses an area near the Blacktail Fault at Barrett's Diversion Dam, where the Blacktail uplift was developed by late movement of this active fault (described in more detail below). Below the diversion, the valley is characterized by agricultural activity and the irrigation that supports it, stemming from the irrigation and flood control functions of Clark Canyon Reservoir. Surface soils in the hills and mountains are generally loamy and sandy with rock escarpments and fragments, while the alluvial valley soils are loamy and clayey. Watercourses have generally carved soil down to bedrock and loose gravel.

Seismic activity in the southwestern region of Montana is significant and has been shown to have the highest degree of tectonic plate movement within the state (Bartholomew et al., 1999). A portion of the region borders the highly active Yellowstone caldera in Wyoming. Documented earthquakes occurred in 1925, 1959, and 1983, centered at Clarkston Valley, Hebgen Lake, and Borah Peak, Idaho, respectively. These epicenters all lie within 90 miles of Clark Canyon Reservoir, and at least one of the earthquakes (Hebgen Lake) was felt in nine states and three Canadian provinces. It also caused subsidence within the Hebgen Lake Basin of as much as 6.7 meters, as well as a landslide large enough to dam Madison Canyon and create Earthquake Lake.

The nearest faults to Clark Canyon Dam are known as Red Rock Fault and Blacktail Fault. Both run approximately southeast to northwest, perpendicular to the flow of the Beaverhead River downstream of the dam. Red Rock Fault is about 10 miles upstream along the Red Rock River, while the Blacktail Fault is about 12 miles downstream toward the city of Dillon. Being close to a population center, Blacktail Fault has been well-documented as an active fault.

In 2000, Reclamation commissioned a study to assess the amount of sedimentation that has accumulated in Clark Canyon Reservoir since operation of the earthfill dam began in 1964. The sedimentation is generally believed to be contributed by the drainage area to the reservoir, although a minor amount is trapped upstream by Lima reservoir. Loss of storage below the normal operating water surface level could also occur from shoreline erosion, although this has not been studied. Reclamation's mapping of the reservoir concluded that 2.3 percent of the reservoir's storage volume had been lost since operation began, an average of 114.7 acre-feet of sedimentation per year.

The areas where construction of the proposed project would occur are all areas that were disturbed during construction of Clark Canyon Dam, completed in 1964. The valve house, powerhouse, and staging area would all be located on the toe of the downstream face of the dam adjacent to the existing spillway and stilling basin. There would be no new penetrations through the dam structure; the project would use the existing outlet tunnel downstream of the intake gates by installing a new steel liner in the tunnel with a new trifurcated diversion structure to allow for flows to the existing outlet stilling basin or to the proposed powerhouse.

3.3.1.2 Environmental Effects

Effects of Construction

Ground disturbance associated with construction of the project, including the powerhouse, access road, and transmission line, could release sediment into nearby wetland areas and the Beaverhead River downstream of the dam, and it could adversely affect the structural stability or seepage characteristics of the existing dam. Turbidity could also be increased by a change in flow patterns through the dam during construction.

Proposed construction work would disturb multiple areas on the downstream side of the dam, as well as inside the dam. The disturbance downstream of the dam would include burial of 0.3 miles of transmission line. The applicant proposes to lengthen the existing access road and place a temporary staging and spoil site on the uphill side of the proposed transmission line burial corridor and existing access road.

To minimize soil erosion and dust, protect water quality, and minimize turbidity in the Beaverhead River, the applicant proposes to implement the measures contained in its ESCP. The ESCP includes best management practices (BMPs) such as:

• Defining clearing limits within project area and buffer zones around sensitive areas, including wetlands;

• Stabilizing construction access road entrances and exits, parking and staging areas;

• Controlling flow rates coming onto and leaving the project area utilizing, but not limited to, swales, dikes, sediment ponds, or sediment traps, as necessary;

• Installing sediment controls to minimize erosion and stabilize soils including, but not limited to, silt fences, wattles, interceptor dikes, swales, and vegetative filtration;

• Preserving natural vegetation and stabilize soils utilizing nets, blankets, mulch, and seeding, as necessary;

• Protecting slopes utilizing, but not limited to, terracing or pipe slope drains;

• Protecting stormwater drain inlets utilizing catch basin inserts;

• Stabilizing channels and outlets;

• Controlling the release of pollutants to protect water quality and aquatic resources by keeping chemical storage areas covered or designating a concrete handing area; and taking all precautions to avoid spills (

e.g.

herbicides would not be mixed within 200 feet of wetlands or open water, maintain spill kits on-site, etc.);

• Controlling de-watering processes within the project area;

• Visually inspecting all construction and disturbance areas every two weeks throughout the entirety of construction activity, or after any project related discharges or rain events; and

• Using existing developed and primitive roads where possible to access the project area and construction features.

Constructing facilities at an existing earthfill dam such as the Clark Canyon Dam has the potential to adversely affect the dam's structural ability to withstand a seismic or flood event by adversely affecting the seepage characteristics of the dam. The applicant proposes to construct the powerhouse and appurtenant facilities in a manner to avoid any effects on reservoir levels or dam stability. The proposed hydroelectric facilities would also be designed to withstand seismic and hydrostatic forces.

To ensure that the area is suitable for the foundation loading of the hydroelectric facilities, geotechnical borings would be drilled and the results reviewed and approved by the Commission and Reclamation. To confirm that the proposed facilities would not affect the stability of the existing structures, and to confirm that the proposed structures would be compatible with applicable seismic and hydrostatic load standards, the applicant would finalize design plans and drawings and submit for Commission and Reclamation review and approval. The plans would include structural drawings, construction methods, and mitigation measures for potential impacts from construction of the powerhouse, steel conduit liner, shaft house, transmission line, and all appurtenant facilities. The Commission and Reclamation would review final design plans before the start of construction, as well as the results of geotechnical borings. Borings would be located and drilled after final design plans specify the exact location of the hydroelectric facilities. The results of the borings would show the composition of the subsurface geology and dam structures, including the location of bedrock, to confirm the suitability of the final design location of the powerhouse and foundation loading.

Our Analysis

The proposed project would disturb areas downstream of the dam during construction of the powerhouse and appurtenant facilities, burial of the transmission line, and upgrade of the access road. The ESCP would control sediment release, if properly implemented. Approved and properly implemented erosion and sediment control measures, consistent with the Commission's guidelines, would minimize sediment releases that could result from construction disturbance. Inspection and maintenance of the erosion and sediment control structures, especially around rainfall events and disturbance activities, would ensure compliance with Commission guidelines. With effective erosion control measures in place, sediment from construction activities would not likely enter wetlands or the Beaverhead River.

The applicant's proposal to avoid any jurisdictional wetlands and route the transmission line along the uphill side of the existing access road would limit the potential for sediment release from construction activities into wetlands and the Beaverhead River. Although project construction would result in ground disturbance and could potentially result in sediment release into the river, the applicant's proposed plan would protect environmental resources.

Effects of Operation

Potential effects on geology and soils during project operation could occur as a result of sediment release caused by concentrated runoff. Revegetated or paved surfaces such as the access roads, parking area, or walkways could generate runoff. If improperly managed, that runoff could cause rills or gullies that transport sediment into Beaverhead River. Similarly, construction areas and the spoil area, especially the buried transmission line corridor, could be susceptible to increased erosion if revegetation work were not completed properly.

Our Analysis

Post-construction stabilization and effective site restoration as discussed in section 3.3.3.2,

Environmental Effects, Terrestrial Resources,

would minimize long-term effects on environmental resources. With effective erosion control measures in place, sediment from construction activities would not likely enter wetlands or the Beaverhead River.

Once in operation, the project should have little or no effect on geology and soils. Proper implementation of the applicant's ESCP would prevent excessive runoff that could possibly cause rills or gullies to form, thereby protecting water quality, wetlands, and soil resources. Intake and discharge of water for project use would be confined to areas already established for those purposes.

3.3.2 Aquatic Resources

The proposed project has the potential to affect water quantity, water quality, and fisheries resources in Clark Canyon Reservoir and the Beaverhead River. The Affected Environment section describes these resources in the project area.

3.3.2.1 Affected Environment

Water Quantity

The hydrology of the Beaverhead River is dictated by Reclamation's operation of the Clark Canyon Reservoir as an irrigation and flood control facility. On average, the lowest reservoir elevations typically occur in late summer or early fall at the end of the irrigation season, with the highest reservoir elevations typically occurring in mid-May just prior to the irrigation season. For the period of record of 1965 to 2007, the estimated mean monthly streamflow downstream of the dam ranged from a low of about 170 cfs during the winter to a high of about 750 cfs during the peak summer irrigation season (figures 3 and 4). Starting in April, water releases from the reservoir are increased until mid-July when the pool in the reservoir is nearly full. Flows then drop until around mid-October before stabilizing until the following April, which corresponds to a period of reduced reservoir storage.

Extended periods of low flows (<100 cfs) occurred in 1967, 1975, 1986, 1990-1993, 2001-2009, and 2013-2014. The low-flow period of 2001-2004 reduced the reservoir storage to its lowest level since construction, with flow releases during this period ranging from a fall/winter low of about 30 cfs to a summer high of about 500 cfs (figure 3). Unusually high flow years occurred in 1976, 1984, 1996, and 1999. In 1984, spring snow melt, accompanied by spring rains, contributed to a maximum combined release of 2,586 cfs through the dam outlet works and spillway.

EN29JN16.003

Discharge from Clark Canyon Dam during the fall through winter period generally averaged between 200 to 300 cfs from 1965 to 2003. The maximum discharge recorded for the period of 1965 to 2003 for the fall and winter seasons ranged from a high of about 1,300 cfs in October to about 700 to 500 cfs from November through February.

EN29JN16.004

Minimum instream flow releases specified by existing water uses during non-irrigation (winter) seasons are 23 cfs during dry conditions.

Water Quality

Water quality standards applicable to Clark Canyon Reservoir and the Beaverhead River downstream of Clark Canyon Dam are shown in table 2. These waters are classified as B-1, which means they are to be maintained suitable for drinking, culinary, and food

processing purposes, after conventional treatment; bathing, swimming and recreation; growth and propagation of salmonid fishes and associated aquatic life, waterfowl, and furbearers; and agricultural and industrial water supply.

Table 2—Numeric Water Quality Criteria Applicable to the Clark Canyon Dam Hydroelectric Project

[Source: License application as modified by staff]

Parameter

Background condition

Numeric criteria

Temperature

32°F to 66 °F

1°F maximum increase above background.

66°F to 66.5 °F

No discharge is allowed that will cause the water temperature to exceed 67 °F.

>66.5 °F

The maximum allowable increase in water temperature is 0.5°F.

At saturation (approximately 7.5 mg/L or higher) from June 1 through August 31 and 8.0 mg/L from September 1 through May 31

Total gas pressure

110 percent saturation.

Turbidity

5 NTU above background.

Notes:

DO—dissolved oxygen; °F—degrees Fahrenheit; mg/L—milligram per liter; NA—not applicable; NTU—nephelometric turbidity unit.

Montana does not have absolute standards for water temperature. Temperature regulation is relative and prohibits increases of various amounts above naturally occurring water temperature.

The freshwater aquatic life standard for dissolved oxygen in Montana is contingent on the classification of the waterbody and the presence of early life stages of fish.

These project-specific DO standards were stipulated by Montana DEQ's certification condition 3.

Red Rock River and Horse Prairie Creek (the primary tributaries to Clark Canyon Reservoir), as well as the Beaverhead River downstream to Grasshopper Creek (11.8 miles downstream from Clark Canyon Dam), are identified on the state of Montana's CWA section 303(d) list as being water quality impaired (EPA, 2008). The Red Rock River is listed as being impaired due to habitat alteration, flow alteration, sediment, temperature, lead and zinc. Horse Prairie Creek is impaired by flow alteration, arsenic, cadmium, copper, lead, mercury, and zinc. The Beaverhead River from Clark Canyon Dam to Grasshopper Creek is listed as being impaired due to flow and habitat alteration, as well as lead, and downstream from Grasshopper Creek, the river is listed as being impaired by flow and habitat alteration, sediment, and temperature. Montana DEQ is currently working on defining acceptable total maximum daily loads (TMDLs) for the Red Rock River and Beaverhead River Basins.

Clark Canyon Reservoir is included in Montana DEQ's 2014 Integrated Water Quality Report as impaired by a non-pollutant for alterations to flow regimes relating to drought impacts and irrigated crop production. These impacts cause impairments for the beneficial uses of primary contact recreation and aquatic life but because these impairments are not considered pollutants, no TMDL will be established (Montana DEQ 2014).

The causes of water quality impairment in the Beaverhead River Basin identified on the 303(d) list include grazing in riparian or shoreline zones, flow regulation and diversion for irrigated crop production, leaching of toxic materials from abandoned mines, and land clearing for development. Each of these sources likely contributes to a cumulative reduction in water quality in the project area, although water quality in Clark Canyon Reservoir and in the Beaverhead River downstream of Clark Canyon Dam is generally sufficient to support a high-quality trout fishery.

The applicant collected water quality data at six sites in the project vicinity between 2007 and 2009. The sites were chosen to provide baseline data for assessment of the potential effects of project construction and operation on water quality of the Beaverhead River. Monitoring efforts documented DO and temperature profiles in the forebay area of Clark Canyon Reservoir, as well as DO, temperature, TDG, and turbidity at five sites in the Beaverhead River downstream from the dam.

Clark Canyon Reservoir

Reservoir profiles reported by the applicant during the sampling period captured reservoir dynamics over a wide range of reservoir elevations. In 2007, reservoir surface elevations dropped about 15 feet during the sampling period from a high of about 5,535 feet during early May to a low of about 5,520 feet from August through October. The reservoir was cool but well stratified in May, with surface temperatures of approximately 14.5 degrees Celsius (°C), a thermocline depth of about 10 meters, and hypolimnion temperatures of approximately 10 °C. Surface temperatures continued to warm through July, but began to cool in August and were down to 12.5 °C by September. The maximum surface temperature observed was in early July when surface waters reached 22 °C. The thermocline was relatively constant at about 10 meters deep despite changes in reservoir elevations and reservoir temperatures. Stratification was strong from May through July, but lessened by mid-August and was completely absent by late September when the profile reflected complete mixing throughout the water column and a uniform temperature of approximately 12.5 °C.

DO patterns from data collected in 2007 reflected the temperature stratification of Clark Canyon Reservoir. Surface DO concentrations were highest in May at about 9 mg/L, but declined below the thermocline and were below the standard of 8 mg/L in the bottom 3 meters of the reservoir. Late June showed a similar pattern of stratification, with only slightly lower DO concentrations. In July and August, DO levels were below the 8 mg/L water quality standard at the surface, and fell below 4 mg/L at depths greater than 15 meters. By late September, however, the reservoir uniformly mixed and DO concentrations met and exceeded the standard of 8 mg/L. Reservoir profiles of DO were also performed in 2010. The 2010 reservoir profiles showed that fall turnover occurred during late September or early October. However, the lowest hypolimnion DO level was 1.3 mg/L in late July during that sampling year.

Additional information about reservoir stratification patterns is available from temperature and DO profiles measured by Reclamation in 2001, 2002, and 2003 (Reclamation, 2005). In 2001, a substantial degree of stratification was evident in late June and in mid-August, with complete mixing (as reflected by uniform temperature and DO profiles) occurring by the next measurement on October 14. In 2002, the reservoir exhibited

substantial stratification in mid-June, was weakly stratified in mid-September, and reflected complete mixing by the next measurement on October 8. In 2003, stratification was not evident in July, but no profiles were measured after July 28 in that year.

Beaverhead River

The applicant conducted continuous monitoring of water temperature, DO, TDG, and turbidity at a site approximately 300 feet downstream of Clark Canyon Dam from June 2007 through 2009 and also collected water temperature, DO, and turbidity data at this site again in 2013. In addition, the 2009 monitoring effort included four additional sites located 0.9, 3.0, 5.7, and 10.7 miles downstream from Clark Canyon Dam. Water temperature, DO, TDG and turbidity were monitored for a minimum period of 48 hours in each month at each of these sites.

Temperature

—Water temperatures were monitored in the Beaverhead River from 2007-2009 and again in 2013. Water temperatures measured in 2007 at the site 300 feet downstream from the dam gradually increased from 14.3 °C in late June, peaked at just over 21 °C on August 4, and then gradually decreased to just over 16 °C in early September. The range of daily variation decreased as the summer progressed, but averaged just less than 1 °C. Water temperatures were highest around noon and lowest around midnight. Data collected in 2008 and 2009 showed similar patterns between years, with winter temperatures generally less than 5 °C and summer temperatures reaching 16 to 17 °C. Sites closest to the reservoir outlet were generally the coolest in the summer, due to the proximity to cool reservoir waters.

Temperature observations in 2013 were consistent with historical monitoring, with winter temperatures generally less than 5 °C and summer temperatures peaking at approximately 18 °C with a maximum daily average temperature of 18.6 °C recorded on August 25 (figure 5). The applicant states that the range of daily variation throughout the year averaged less than 1 °C in 2013 which is consistent with data collected in 2007.

EN29JN16.005

Dissolved Oxygen—Minimum DO values measured at the five monitoring sites from May 2007 through 2009 generally exceeded the 8-mg/L (March through September) and 4 mg/L (October through February) water quality standards in most months and locations, although measurements at sites closest to the reservoir did measure levels lower than the state standard of 8 mg/L at times during the late summer and early fall months (figure 6).

EN29JN16.006

Monitoring conducted near the reservoir outlet in 2008 and 2009 revealed some diel DO patterns, primarily during the spring and winter months. For instance, DO generally increased during the day from morning to late afternoon before declining. The greatest amplitudes were observed during the spring. During the summer months, there was little or no diel pattern. The applicant stated that discharges during those times likely reduced the opportunity for DO to be absorbed into

solution.

The heavy dashed line applies to data collected at RM 5.7.

DO observations in 2013 were consistent with historical monitoring. Seasonal highs occurred during the spring and winter months, with a peak concentration in the month of May, and lowest concentrations occurring in late summer. DO concentrations were temporarily below the 8 mg/L standard during the month of June, and concentrations stayed below the standard continuously from mid-July through September during the 2013 sampling year (figure 7).

Upper Missouri Waterkeeper, Montana Trout Unlimited, Rhonda Sellers (on behalf of the International Federation of Fly Fishers), and several local residents filed comments stating concerns with recent algal blooms that occurred in the Beaverhead River downstream of the dam during the summers of 2014 and 2015.

Recent limnological data from Montana DFWP collected in the summer of 2015 indicate that the reservoir likely contributes to nitrogen and phosphorus loads being transported downstream (Selch, 2015). Downstream transport of nitrogen and phosphorous can feed algal growth in the summer which can also contribute to lower DO levels in the Beaverhead River during these months.

See

comment letters filed by Wade Fellin on February 26, 2016; Brian Wheeler on March 1, 2016; Michael Stack on March 8, 2016; Tim Hunt on March 11, 2016; Steve Hemkins on March 14, 2016; Kimball Leighton on March 17, 2016; Gregg B. Messel on March 21, 2016; Woody Bailey on March 22, 2016, Rhonda Sellers on March 24, 2016; Christian Appel on March 24, 2016, Cordell Appel on March 24, 2016, and Luke Massaro on March 24, 2016.

EN29JN16.007

Total Dissolved Gas

—Current dam operations cause water to be vigorously aerated as highly pressurized flows exit the regulating outlet. As a result, the flow rate through the dam is highly correlated with TDG saturation. The highest flows can lead to oversaturation and TDG levels above 115 percent saturation which exceeds the state standard for TDG of 110 percent saturation and potentially harm fish.

Although no spill occurred over Clark Canyon Dam during the 2007 monitoring period, TDG saturation levels exceeded the state standard of 110 percent saturation during high flow periods in 2007, and did so again during the 2008 and 2009 monitoring years (figure 8). The applicant states that statistically, the 110 percent saturation standard was exceeded when flows were greater than about 360 cfs. Overall, TDG levels appeared to track discharge from Clark Canyon Dam and frequently exceeded state standards between June and September. Peak TDG levels exceeded 115-120 percent saturation during mid-summer in all years, when flows were in the range of 600 to 900 cfs. Measurements taken at downstream sites indicated that saturation levels were reduced as water moved downstream, although at times TDG levels remained above the 110 percent standard at the next three measurement sites, extending 5.7 miles downstream from Clark Canyon Dam.

EN29JN16.008

Turbidity

—Turbidity measurements reported by the applicant indicate that turbidity levels in the Beaverhead River downstream of Clark Canyon Dam are generally low (

i.e.,

below 5 NTU per every 48-hour sampling event), but do show some seasonal variation. For example, in 2007, average turbidity values measured 300 feet downstream from the dam ranged from a low of 0.02 NTU in July to a high of 4.7 NTU in September (figure 9). Overall, turbidity levels measured at the site closest to the dam were highest in the fall when reservoir levels were low, which may be attributable to re-suspension of sediment deposits due to wave action as the elevation of the reservoir was lowered over the irrigation season. Peak instantaneous turbidity levels of between 11 and 13 NTU occurred in mid-August and in late September, respectively. Longitudinal sampling at the four downstream sites showed relatively low average turbidity levels at all sites except in May, when the 48-hour average turbidity level increased from less than 2.7 NTU at the first three sites to 7.33 and 21.48 NTU at the sites located 5.7 and 10.7 miles downstream of Clark Canyon Dam, respectively. Elevated turbidity levels at the downstream sites were most likely attributable to suspended sediment contributed from tributary inflows.

In 2008, average turbidity levels ranged between 0.2 and 29.3 NTU. The 29.3-NTU peak in turbidity reported in March 2008 at station RM 0 is of questionable accuracy because this peak is not reflected in measurements taken at the downstream monitoring stations (figure 9). In its CWQMP, the applicant states that such spikes may be due to the gradual buildup of algae on the sensor or to debris becoming lodged in the probe casing near the sensor, thus causing a faulty reading.

EN29JN16.009

Except for the questionable spike in turbidity observed at the site closest to the dam in March 2008, turbidity remained generally below 5 NTU at all sites throughout the majority of the 2008 and 2009 monitoring years. Exceptions to this were most often recorded at the monitoring site located the furthest downstream of the dam. For example, during May 2009, a measurement of about 20 NTU was recorded at this site. The applicant noted that this site occurs below several tributaries and irrigation returns and is downstream of river portions that may be more vulnerable to shoreline erosion, all of which can elevate turbidity in the river.

In addition to tributary inflow and irrigation sources, turbidity may also be affected in Clark Canyon Reservoir and in the Beaverhead downstream due to algal blooms. Recent limnological and bathymetric survey data from Montana DFWP and Montana DEQ collected in 2015 indicated that both inorganic fine sediments and concentrations of nitrogen and phosphorus are likely being transported downstream through the existing outlet works (Selch, 2015; Flynn, 2015). Downstream transport of nitrogen and phosphorous can feed algal growth and, along with other sediment sources, contribute to turbid conditions in the Beaverhead River downstream of Clark Canyon Dam.

Fishery Resources

Fish Community

The Beaverhead River is recognized as one of the most popular and productive trout fisheries in North America and is designated as a blue ribbon fishery by Montana DFWP. Native fish species occurring in the Beaverhead River and in Clark Canyon Reservoir include mountain whitefish, burbot, mottled sculpin, mountain sucker, longnose sucker, and white sucker. Introduced fish species include rainbow trout, brown trout, brook trout, redside shiner, and common carp. Brown and rainbow trout are well established, and often attain trophy size in the Beaverhead River. Special status species that may occur in the project area include the westslope cutthroat trout (

Oncorhynchus clarki lewisi

) and Montana Arctic grayling (

Thymallus arcticus montanus

The westslope cutthroat trout is a subspecies that occurred historically throughout the Northern Rocky Mountain states, including the Beaverhead River Basin. Genetically pure and near-pure populations have been documented in portions of the Beaverhead River in recent years, and some individuals may occur in the project vicinity. The U.S. Bureau of Land Management (BLM) categorizes the westslope cutthroat trout as having special status, which indicates that the species is imperiled throughout at least part of its range and documented to occur on BLM lands. It is currently listed as a S2

species by Montana

DFWP, meaning that it is at risk because of very limited and potentially declining numbers, extent, and/or habitat, making it highly vulnerable to global extinction or extirpation in the state. Current management actions for the westslope cutthroat trout by federal and state agencies include the identification and protection of remaining populations; the evaluation of areas that provide suitable habitat for range expansion; and the expansion of the distribution of genetically pure strains (Sloat, 2001). Montana DFWP and sister state agencies have signed a Memorandum of Understanding (MOU) and Conservation Agreement that is part of a coordinated multi-state, range wide effort to conserve westslope cutthroat trout (Montana DFWP, 2007). Genetically pure strains of westslope cutthroat trout persist in some of the headwaters of unobstructed tributaries within their former range where colder temperatures appear to provide them with a competitive advantage over introduced species that require higher temperatures to reach optimal growth, such as stocked rainbow trout (Sloat, 2001).

S1 species are at high risk because of extremely limited and/or rapidly declining population numbers, range and/or habitat, making it highly vulnerable to global extinction or extirpation in the state. S2 species are at risk because of very limited and/or potentially declining population numbers, range and/or habitat, making it vulnerable to global extinction or extirpation in the state. S3 species are potentially at risk because of limited and/or declining numbers, range and/or habitat, even

though it may be abundant in some areas (Montana NHP and Montana DFWP, 2016).

The Montana Arctic grayling historically occurred throughout the upper Missouri River Basin upstream of Great Falls, Montana, including the Beaverhead River. In recent years, the Montana Arctic grayling has been stocked into the Beaverhead River downstream of the city of Dillon in an attempt to re-establish the species. The species is listed as sensitive by the U.S. Forest Service, indicating there is a concern for population viability within the state due to a significant current or predicted downward trend in populations or habitat. The species has also been petitioned for listing under the ESA several times since 1991 although the FWS determined it was not warranted for listing in 2014 (79 FR 49384). BLM affords the species special status and Montana DFWP lists it as G1-S1 species, indicating it is at high risk because of extremely limited and potentially declining numbers, extent, and/or habitat, making it highly vulnerable to global extinction or extirpation in the state.

Fisheries in the Beaverhead River Basin have been cumulatively affected by grazing in riparian or shoreline zones, flow regulation and diversion for irrigated crop production, land clearing for development, and cumulative effects on water quality from these and other sources.

Beaverhead River Fishery

The Beaverhead River between Clark Canyon Dam and Barrett's Diversion Dam is a productive tailwater fishery. This portion of the river is designated as a blue ribbon fishery and angler use can be very high from May through November. The dominant fish species in the Beaverhead River are brown trout and, to a lesser degree, rainbow trout. While neither of these species is native to the river, their populations are considered to be wild and self-sustaining.

Surveys to determine the abundance of age 1+ rainbow and brown trout have been conducted by Montana DFWP within the project vicinity annually since 1986. Survey data collected by between RM 74.9 to RM 73.3 in the Beaverhead River below Clark Canyon Dam between 1991 and 2013 are shown on figure 10 below. Brown trout abundance was observed to range from 473 fish per mile to 2,619 fish per mile and averaged 1,369 fish per mile between 1991 and 2013. Rainbow trout abundance was observed to range from 99 fish per mile to 680 fish per mile and averaged 305 fish per mile between 1991 and 2013. Oswald (2003) reports that rainbow trout in the reach downstream of Clark Canyon Dam have declined as the population of brown trout has expanded.

EN29JN16.010

Trout abundance in the survey area of the Beaverhead River has been observed to fluctuate with discharge flows which are generally attributable to regional weather conditions. Populations of both species appear to be adversely affected in dry water years, when the minimum flow released from Clark Canyon Dam may be reduced substantially during the winter (non-irrigation) season. Oswald (2006) reported that the number of brown trout greater than 18 inches in length in the Beaverhead River exceeded 600 fish per mile from 1998 to 2000, after a series of wet water years when the mean winter flow releases were over 200 cfs. Dry water years from 2001 through 2006 resulted in winter flow releases of less than 50 cfs, and the estimated number of brown trout greater than 18 inches in length subsequently declined to about 400 fish per mile by 2002, to 300 fish per mile by 2004, and to 100 fish per mile by 2006.

Gas bubble trauma has been documented in trout populations in the Beaverhead River (Oswald, 1985, as cited by Clark Canyon Hydro, LLC, 2015a). The primary cause of gas bubble trauma in regulated systems is TDG supersaturation from water spilled at dams, which commonly occurs when entrained air is dissolved in water under pressure at depth in plunge pools (Beeman et al., 2003). Gas bubble trauma induces a variety of sub-lethal and lethal effects in fish and other aquatic species (EPRI, 1990; Weitkamp and Katz, 1980). Gas bubble trauma is characterized by the formation of gas bubbles in the body cavities of fish, such as behind the eyes or between layers of skin tissue. Small bubbles can form within the vascular system, blocking the flow of blood and causing tissue death. Bubbles can also form in the gill lamellae and block blood flow, occasionally resulting in death by asphyxiation. The effects of gas bubble trauma can range from mild to fatal depending on the level of TDG supersaturation, species, life stage, depth, condition of the aquatic organism, and temperature of the water (Beeman et al., 2003).

In 1983, elevated TDG levels and gas bubble trauma were observed for the first time in the Beaverhead River downstream of Clark Canyon Dam. It was originally believed that the elevated TDG levels were caused by very high flows that included releasing the maximum quantity of flow through the outlet works and—for the first and only time since construction—releasing water through the spillway. Data collected by Oswald (1985) indicated that 8.8 percent of brown trout and 3 percent of the rainbow trout sampled downstream of the dam exhibited gas bubble trauma symptoms. Data collected by Falter and Bennett (1987) during a non-spill period, however, also found elevated levels of TDG in the river. In fact, the highest TDG concentration observed for the non-spill period was 126 percent of saturation compared to 127 percent of saturation during the spill event. Falter and Bennett (1987) suggested that the primary cause of TDG supersaturation downstream of Clark Canyon Dam is the turbulent mixing and plunging of flows released through the existing outlet structure of the dam. Data reported by the applicant indicate that TDG levels continue to remain above state standards, even in the absence of spills.

Other factors that may adversely affect trout populations in the Beaverhead River include outbreaks of bacterial furunculosis, and the more recent introductions of New Zealand mud snail (an exotic nuisance species that may displace species of greater forage value to trout) and whirling disease (Reclamation, 2006).

Clark Canyon Reservoir Fishery

Clark Canyon Reservoir supports a popular fishery for rainbow trout. Other common or abundant fish species include white sucker, redside shiner, brown trout and burbot. Rare species present in the reservoir include brook

trout, mountain whitefish, carp, and westslope cutthroat trout.

Relative abundance of rainbow and brown trout in Clark Canyon Reservoir has been documented since 1980 by gill netting. Rainbow trout abundance in fall surveys conducted between 1989 and 2011 was observed to range from 1.2 fish per net to 50 fish per net in 2004 and 2006, respectively. Rainbow trout abundance in spring surveys conducted between 1980 and 2006 was observed to range from 2.9 fish per net to 18.7 fish per net in 1991 and 2006, respectively. Brown trout abundance in spring and fall surveys has remained fairly low and stable; generally ranging between 1 fish per net and 10 fish per net. To augment the existing rainbow trout population in Clark Canyon Reservoir, Montana DFWP collects and spawns broodstock from Red Rock River. Fertilized eggs from these fish are incubated and reared in hatcheries and then are released into the reservoir as fingerlings or yearlings. Between 100,000 and 300,000 fingerling trout are stocked into the reservoir in most years, and approximately 70,000 additional yearling fish have been released in most years since 2002. Broodstock collection has not been undertaken in some drought years, when flows in the Red Rock River were too low to support a spawning migration of rainbow trout (Reclamation, 2006).

The health of the Clark Canyon Reservoir fishery has been linked to reservoir operation. Reclamation (2006) reports that fish populations typically remain healthy in years where storage remains over 60,000 acre-feet at the end of the summer irrigation season, with year-end storage levels of 100,000 acre-feet or greater providing optimum habitat conditions.

3.3.2.2 Environmental Effects

Flow Releases During Project Construction

Aquatic resources downstream of the dam may be affected during construction if project construction impairs the ability of streamflows to be released downstream into the Beaverhead River, or if it alters water quality compared to existing conditions. Because the existing outlet works would not be available to provide flow releases during part of the construction period, the applicant developed a plan for maintaining the continuity of flow releases during construction in consultation with Reclamation, FWS, Montana DFWP, District, Clark Canyon Water Supply Company, and Montana DEQ. The final Instream Flow Release Plan, incorporating comments received from the consulted agencies, was filed with the license application.

During installation and pressure-grouting of the steel penstock liner, construction of the trifurcation leading to the powerhouse turbines, and installation of associated valves, minimum flows to the Beaverhead River would need to be bypassed around the existing penstock. The applicant estimates that this phase of the construction process would require approximately 8 to 12 weeks, extending from October into December. In its Final Instream Flow Release Plan, the applicant proposes to provide streamflows during this period using electric pumps mounted on a barge anchored in the project forebay. After this phase of the construction has been completed, flow would be released through the existing penstock.

Prior to the start of construction, the number of primary and backup pumps would be determined based on the minimum flow release that would be required by Reclamation during the construction period. The number of primary and backup pump units would be a function of the final construction specifications and bypass flow requirements. The applicant anticipates that one or two pumps would most likely be required, but it proposes to provide as many pumps as are needed to pass the minimum flow specified by Reclamation. The applicant provided cost estimates for the installation of up to four pumps. The applicant proposes to mount the primary and backup pump units on a platform anchored in the forebay near the spillway, and to screen the pump intakes to meet resource agency requirements for fish exclusion.

Magnetic flow measuring equipment would be installed on each discharge pipe so that the discharge from each pump can be measured. In addition, the applicant proposes to install a gaging station immediately downstream of the project prior to construction. Reclamation would be consulted prior to construction regarding how the exchange of flow releases from the regulating outlet to the pumps and back again would occur, and continuous contact would be maintained between representatives of the applicant and Reclamation during this period.

A diesel generator located above the reservoir shoreline would be available to provide backup power in the event of a power outage. The generator would be enclosed in a spill containment unit of sufficient capacity to handle the diesel generator fuel storage. Additionally, an earthen berm would be placed around the generator site. The diesel generator would provide controls for automatic startup and electrical transfer if an outage occurs. The applicant also proposes to provide full-time/24-hour staff attendance of the pumping system when flows are being bypassed around Reclamation's existing intake and outlet works during construction of the proposed penstock.

Our Analysis

The applicant's proposal to implement its Final Instream Flow Release Plan, with provisions to pump flows around the existing penstock to the Beaverhead River at flows dictated by Reclamation, would ensure that streamflows and water quality suitable to protect aquatic life are maintained in the Beaverhead River downstream of the dam during project construction. Providing stable flow releases would be especially important to brown trout and mountain whitefish, which spawn in the Beaverhead River in October and November and rely on stable river flows for reproductive success.

The applicant estimates that this phase of the construction process would require approximately 8 to 12 weeks, extending from October into December. Elevated flows associated with irrigation demands have typically ended by late September. The timing of irrigation releases and the amount of minimum flow to be released after irrigation releases end are determined jointly by Reclamation and the East Bench Joint Board of Control, which is composed of the District and the Clark Canyon Water Supply Company. Minimum flows released during the post-irrigation season are determined using guidelines based on the amount of reservoir storage at the beginning of September plus the total inflow that occurs during July and August (table 3).

Table 3—Clark Canyon Reservoir Release Guidelines (Source: Reclamation, 2006)

September 1 Storage Plus

July-August Inflow

(acre-feet)

Minimum Flow

(cfs)

Less than 80,000

80,000-130,000

130,000-160,000

100

Greater than 160,000

200

Staff examined the end-of-month storage for Clark Canyon Reservoir for the years 1965-2016. Over the period of record, end-of-month storage for the month of September was generally less than 160,000 acre-feet with very few exceptions (Reclamation, 2016). Data for the most recent three years showed that storage for September ranged from 47,983-59,215 acre-feet (Reclamation,

2016). Given the data, we do not expect that the applicant would be required to provide a minimum flow above 100 cfs during the pumping stage of construction. Nevertheless, the applicant commits to being prepared to release whatever flow is required by Reclamation during the construction period. Consultation with Reclamation prior to the start of construction to determine what minimum flows would be required during the construction period, as the applicant proposes, would ensure that a sufficient number of primary and backup pumps are installed to maintain the required minimum release flows. Provision of backup pumps and a backup generator, as proposed by the applicant, would help to ensure that the required minimum flow is maintained in the event of a mechanical failure or power outage. Installation of the backup generator and fuel storage in a containment unit would help to ensure that any spills of diesel fuel are contained and do not enter the waterway.

Additional provisions proposed by the applicant that would help ensure flow continuity during project operation include:

• When flows drop below 87.5 cfs (the minimum hydraulic capacity of the powerhouse), the flow would be gradually transferred to the main penstock through synchronization between the powerhouse and the penstock valves. As flow is reduced through the powerhouse valves, flow would increase correspondingly through the penstock valve, and vice versa.

• The project is being engineered such that, in the event of emergency shut down or during a drop in flows that precludes power generation, the closure of the powerhouse valves and the return of flows to the normal outlet works would be automatically synchronized to eliminate the potential for unintended ramping. There would be no transition between pressurized and non-pressurized flows through the regulating outlet once the project is operational. Upon completion of the project, flows exiting the dam would be pressurized at all exit points except for the spillway.

• A project operator would be on site daily and Reclamation personnel would be notified immediately in the event of an unplanned shutdown or in case of any other type of emergency.

Implementing these measures would help ensure a very low likelihood of unintended ramping or dewatering of aquatic habitat as a result of project operation. Also informing Montana DFWP of any unplanned shutdown would provide that agency with information relevant to its management of fishery resources downstream of the project.

Providing 24-hour attendance of the pumping system for the duration of time that minimum flows are to be maintained by pumping would help avoid or minimize any adverse effects on aquatic resources caused by failure or malfunction of any component of the pumping system. Failure of the pumping system could have catastrophic consequences on fish and aquatic resources, especially brown trout and whitefish that are known to spawn during October and November in areas downstream of the dam. Because the pumps would provide the only means to transfer water from the reservoir to the river, it is anticipated that streamflows downstream of the dam would immediately begin to recede in the event of a pumping system failure. Any potential adverse effects of a pumping failure would be minimized by having properly trained staff on site to ensure a return to normal operations as quickly as possible. Further, installing a water level alarm to detect falling water levels in the Beaverhead River near the instream flow release point could help alert onsite staff of any need to activate back-up pumps or address any unforeseen problems with the pumping system.

Notifying Montana DEQ and Montana DFWP within 24 hours of any unauthorized discharge of pollutants, as the applicant proposes in its CWQMP, would help ensure that best management practices are adhered to and that any spills are addressed in a timely and thorough manner.

Construction Water Quality Monitoring

Montana DEQ's condition 2 stipulates the applicant submit a plan to monitor turbidity, temperature, DO, and TDG during construction. In its CWQMP, the applicant proposes to monitor DO, temperature, and turbidity at a site approximately 300 feet downstream of the proposed powerhouse and parking construction areas while TDG would be monitored immediately below the spillway pool when flows are being bypassed around Reclamation's existing intake and outlet works during construction of the proposed penstock.

If monitoring indicates that the state of Montana standard for TDG of 110 percent saturation is exceeded during pumping, the applicant would reposition the pump outlets until the state standard is met. Data would be transmitted in real time to the construction manager's trailer at the construction site, with mean values recorded at 15-minute intervals. Routine calibration and maintenance of field equipment would be accomplished in accordance with the manufacturer's guidelines.

The applicant's plan also includes provisions to take a vertical profile of dissolved oxygen levels and water temperatures in Clark Canyon Reservoir prior to commencement of pumping activities to ensure that reservoir mixing has occurred. If mixing has not occurred, then the applicant would delay modifying Reclamation's penstock and inlet works until this determination is made; thereby ensuring that any water pumped around Reclamation's penstock does not degrade water quality conditions below the dam.

For turbidity monitoring, the applicant proposes to use 5 NTU as background from which to evaluate turbidity levels generated by construction activities. Should this level be exceeded by more than 5 NTU during construction, the applicant would conduct a ground survey to determine if there is noticeable sedimentation arising from the construction area, take a water sample to verify the reading, and also determine if the probe is functioning properly and clear of algae or other debris. Any event resulting in a discharge of sediment would be reported within 24 hours to Montana DEQ and Montana DFWP to determine the need for corrective measures.

The applicant proposes to submit annual water quality monitoring reports to Reclamation, FWS, Montana DFWP, and Montana DEQ by February 15 following each year of construction. Agencies would have 60 days to review the draft reports and the applicant would submit a final report to the Commission each year addressing agency comments. The reports would include the raw data, documentation of any deviations from water quality criteria, and documentation of procedures to correct any deviations. In addition to annual reporting, the applicant proposes and Montana DEQ's condition 7 stipulates that the applicant notify Montana DEQ and Montana DFWP within 24 hours of any event that results in the discharge of sediment or pollutants as described above. The applicant also proposes to file an incident report with the Commission following the event.

Our Analysis

Monitoring water temperature, DO, TDG, and turbidity prior to and during construction as the applicant proposes and as stipulated by Montana DEQ's condition 2 would ensure that any adverse effects on water quality are

identified and that appropriate actions are undertaken to protect aquatic resources in Clark Canyon Reservoir and in the Beaverhead River downstream of the dam during all phases of construction.

Available information on water temperature and DO levels in Clark Canyon Reservoir indicate that the reservoir is typically well-mixed by late September so that the depth at which water is drawn from the reservoir during the October start date for pumping flows around the existing intake and outlet works should have no effect on downstream water quality conditions. Collecting reservoir profile data prior to the start of project construction, as the applicant proposes, would help to determine whether reservoir mixing has occurred and to assess whether project construction can be initiated without causing any adverse changes in downstream water quality. If pre-construction water quality monitoring indicates that temperature and DO are not uniform by the proposed October start date, delaying the start date of construction would further ensure that downstream water quality is protected prior to initiating pumping activities.

There is some potential that the pumping system used to bypass flows around the existing intake and outlet works during construction of the proposed penstock would provide a different level of aeration than currently occurs in the existing outlet structure, which could affect DO and TDG concentrations. If the pump discharge lines do not extend to the base of the spillway, aeration that would occur as flows pass down the spillway should ensure that DO and TDG concentrations equilibrate with atmospheric conditions, which would likely improve water quality for a temporary period compared to existing conditions. In the unlikely event that water quality conditions during pumping activities are adversely affected and water quality standards are not met, this would be detected by the proposed water quality monitoring program and appropriate measures could be taken (

e.g.,

repositioning the pump outlets) until Montana DEQ's water quality standards for DO and TDG are met.

The proposed temporary pumping facility could affect turbidity levels downstream by taking in sediment through its intake in the reservoir, or by disturbance during installation or removal of the intake. Monitoring turbidity levels downstream of the construction footprint immediately prior to and during construction as described in the applicant's CWQMP would alert the construction manager of a spike in turbidity and the need to determine the cause of the event and any necessary corrective measures to protect water quality. Because turbidity levels near the proposed construction footprint are generally less than 5 NTU during the year, using 5 NTU as a background turbidity level as the applicant proposes would be more than adequate to identify when a spike in turbidity has occurred beyond naturally occurring background levels. Notifying Montana DFWP and Montana DEQ within 24 hours of a discharge of sediment or pollutants would alert the agencies of these events as they occur and allow for these agencies to provide timely recommendations to protect water quality and fish resources downstream during construction.

Providing annual water quality monitoring reports to the agencies and the Commission during construction as the applicant proposes would provide a mechanism to evaluate whether any changes are needed to achieve water quality standards on a year-to-year basis during construction. However, in addition to annual reporting, notifying the agencies within 24 hours of a deviation from water quality criteria, and submitting an incident report to the Commission following the incident would enable the Commission and agencies to determine whether best management practices are being followed and that any needed corrective actions are addressed in a timely manner.

Also, notifying Montana DEQ and Montana DFWP within 24 hours of any discharge of pollutants and submitting an incident report with the Commission following the event would help ensure that best management practices are adhered to and that any spills are addressed in a timely and thorough manner.

Minimum Instream Flows

The applicant proposes that the project be operated as a run-of-release project, in which the flows downstream of the project powerhouse would be dictated by Reclamation, thus the flows would be identical to the flows that would be released by Reclamation in the absence of the project. This is consistent with Reclamation's 4(e) condition 9, which states that the timing, quantity, and location of water releases and release changes from the facilities would be at the sole discretion of Reclamation.

Interior, Upper Missouri Waterkeeper, and Montana Trout Unlimited recommend that the applicant work closely with water users and federal and state agencies to improve minimum instream flow conditions in the Beaverhead River, and support the implementation of the 2006 MOU between Reclamation and Montana DFWP entitled Betterment of the Beaverhead River and Valley.

Interior and Montana Trout Unlimited also recommend that the applicant contribute to improvements in water use efficiency to enhance instream flows for fisheries and environmental health of the river. They recommend that the applicant dedicate 4 percent of the gross hydropower revenues to funding independent technical studies of water efficiency improvements or funding on-the-ground water conservation measures designed to result in instream flow improvements. Interior and Montana Trout Unlimited recommend that the applicant prepare annual reports that explain the uses and expenditures of such funds, and the expected benefits of funded activities. In advance of submitting the annual report to the Commission, the applicant would provide the report to Montana DFWP and FWS for a 30-day review, and attach any comments received on the report when filing it with the Commission.

Our Analysis

Available information indicates that trout populations in the Beaverhead River are adversely affected by low flows that occur during the non-irrigation season and that fish populations in Clark Canyon Reservoir are adversely affected by low reservoir levels during periods of drought. Encouraging the implementation of water conservation strategies in the basin could alleviate adverse conditions that occur in Clark Canyon Reservoir and in the Beaverhead River during drought conditions. However, we note that operation of the project as proposed by the applicant would not cause any changes in the flows in the Beaverhead River or on water storage levels in Clark Canyon Reservoir.

The 2006 Reclamation/Montana DFWP MOU includes the following elements: (1) Identify environmental degradation issues of the Beaverhead River; (2) investigate possible solutions to correct degradation issues; (3) review Clark Canyon Reservoir operation to increase river and reservoir environmental health; (4) explore water conservation projects; (5) describe fishery goals and fish management objectives; and (6) work through a collaborative process with interested groups to develop resource management strategies to improve the environmental health of Clark Canyon Reservoir and the Beaverhead River. Implementing the applicant's proposed water quality

monitoring program would assist with identifying any environmental impacts associated with project construction and operation, and determine whether measures are needed to address project effects. The monitoring program would also contribute information on water quality conditions that would be useful to Reclamation and Montana DFWP as they pursue implementation of the MOU.

The applicant's proposal to operate the project to provide flows determined by Reclamation, consistent with Reclamation's 4(e) condition 9, would ensure that any changes in reservoir operation or flow regimes implemented under the MOU or through any other agreements that Reclamation enters into would not be impeded by operation of the project.

We make our final recommendation for water efficiency improvements in section 5.2,

Comprehensive Development and Recommended Alternative.

Water Quality Operation Effects

Montana DEQ's condition 3 stipulates that the applicant maintain DO levels at saturation (approximately 7.5 mg/L or higher, depending on the temperature of the reservoir water at the intakes) from June 1 through August 31 and 8.0 mg/L the rest of the year while operating. Condition 5 stipulates that the applicant submit a plan prior to construction describing any project design engineering modifications for maintaining DO at these levels. Condition 4 stipulates that the applicant maintain TDG levels at 110 percent or lower downstream of the project while operating.

Diverting water through the applicant's proposed penstock and turbines at Clark Canyon Dam has the potential to reduce DO concentrations downstream compared to current conditions by reducing the turbulence and the entrainment of gases in water exiting the powerhouse. Reduced DO concentrations may limit salmonid growth and reproduction and delay embryonic development and hatching of juveniles if concentrations remain low for extended periods (EPRI, 1990). In order to address potential DO and other water quality concerns during project operation and to comply with Montana DEQ's certification conditions, the applicant proposes to construct and operate an aeration basin downstream of the powerhouse and to implement its Revised DOEP during project operation which includes: (1) Procedures for monitoring and reporting temperature, DO, and TDG levels in project waters for a minimum of five years following initial project operation; (2) procedures for enhancing DO concentrations for water exiting the tailrace; and (3) corrective measures and emergency shutdown procedures to be implemented if deviations from state water quality criteria occur during project operation. The applicant states that the plan was developed in consultation with Reclamation, FWS, Montana DFWP, and Montana DEQ. Water quality monitoring provisions included in the plan are evaluated in section 3.3.2.2,

Post-Construction Water Quality Monitoring.

The proposed aeration basin would consist of three 45-foot-long, 10-foot-wide frames containing 330 diffusers with the capacity to add additional frames if needed. The diffuser system would feature two mechanical blowers, an electronic control system, and ducted aeration diffuser disks to inject fine bubbles of air into the water column to provide the additional aeration. The applicant states that the blower and diffuser system would be designed with the capacity to elevate DO levels by a maximum of 7.5 mg/L before the water enters the Beaverhead River and could be adjusted based on the level of aeration needed to meet state criteria. The applicant anticipates that operation of the aeration basin would likely occur from June through mid-September each year, which is the time that DO concentrations at the bottom of the reservoir (

i.e.,

near the depth of the intake) are expected to be at their lowest levels of the year.

The blower for the aeration basin would include sensors to monitor flow rates and could be adjusted by the operator using controls located both remotely and in the powerhouse. The volume of air supplied by the blower would be based on the level of DO enhancement that is required for a given volume of water and would take into account empirically observed oxygen transfer rates. The applicant states that in early summer, as DO levels decline, the air diffusers in the aeration basin would be gradually brought online to maintain DO concentrations in the Beaverhead River downstream. If DO concentrations decline to such levels that the diffusers are insufficient to meet Montana DEQ's DO criteria (

i.e.,

7.5-8.0 mg/L) during these months, then flows would be gradually shifted through the cone valves to the existing project works to provide additional aeration beyond that provided by the aeration basin alone.

This shift in flow would occur either automatically based on feedback from the applicant's water quality monitoring probes or manually by an operator as needed.

The applicant states the shift of partial flows to the cone valve can function to aerate water using the existing outlet works in addition to the proposed aeration basin thereby potentially further enhancing DO levels beyond what the aeration basin would provide alone.

In an emergency shutdown or if probes at compliance monitoring Site 3 located approximately 300 feet downstream of the project in the Beaverhead River (described further below in section 3.3.2.2

Post-Construction Water Quality Monitoring

) show that Montana DEQ's DO criteria cannot be met, the project would automatically trip offline, triggering the closing of the wicket gates on the turbines and simultaneously opening the cone valve, transferring all flows through the cone valves at the existing project works. If blowers malfunction during the time that the applicant needs to provide additional aeration, the project would remain offline until the backup blower is connected or the blowers are replaced. The applicant also proposes to notify Reclamation immediately in the event of an unplanned shutdown or any other type of emergency that occurs during project operation.

Montana DFWP recommends that the applicant's aeration system be designed to achieve water quality standards downstream when water entering the project works has DO concentrations of 0 mg/L or the applicant should be willing to shut the project down. In its reply comments, the applicant reiterated that its proposed aeration basin is designed to provide the necessary level of DO enhancement downstream, but in any case it would shift flows through the existing outlet works or shut the project down as a last resort to meet water quality standards.

In addition, Montana DFWP and Upper Missouri Waterkeeper recommend that the applicant evaluate the need for dam infrastructure alterations and/or changes in long-term operations to minimize downstream turbidity resulting from entrainment of organic material or inorganic fine sediment from the reservoir into the project works. In its reply comments, the applicant stated that the Clark Canyon Project would not alter the depth of the reservoir intake, or the rate, volume, or velocity of water withdrawn. As a result, the applicant contends that minimizing entrainment of suspended organic and inorganic material is not within its operational control.

Our Analysis

Installation of turbines at the outlet works as proposed by the applicant has the potential to alter TDG levels downstream of the project. Under existing conditions, water leaving the outlet structures is subject to aeration and plunging as it exits the outlet works, which likely causes supersaturated TDG levels that have been documented in the dam tailrace during the months of June through September (

see

Figure 8). Elevated TDG levels may injure or kill fish that are exposed depending on the level of TDG supersaturation, species, life stage, depth, condition of the aquatic organism, and temperature of the water (Beeman et al., 2003). Passing water through the turbines would reduce the plunging effect and turbulence that occur under existing conditions, as well as the potential for entrained air to enter solution under pressure in the outlet works and in the spillway pool, thereby reducing the potential for TDG supersaturation. Thus, when flows are within the operating range of the project (

i.e.,

between 87.5 and 700 cfs), we expect that the potential for TDG supersaturation would be reduced compared to existing conditions which would benefit aquatic resources in the Beaverhead River downstream of the dam. Based on mean monthly flow release data for Clark Canyon Dam, we expect flow releases to be within this range a majority of the time (see figures 3 and 4). While it is reasonable to expect that TDG levels would be lowered during project operation (as compared to not operating the project), it is difficult to predict whether Montana DEQ's criteria of 110 percent saturation could be maintained at all times during project operation.

This would especially be the case when flow release requirements exceed the 700-cfs hydraulic capacity of the powerhouse. Under this scenario, additional flows would bypass the powerhouse penstock at the trifurcation and would be discharged through the existing outlet works, and in rare circumstances, through the spillway. As previously noted, TDG supersaturation frequently occurs when flows are released through the existing outlet works at the dam. Therefore, any time that flows exceed the 700-cfs capacity of the powerhouse which can occur at times during the peak summer irrigation season (

see

figures 3 and 4), it would not be unreasonable to expect that TDG supersaturation could occur. We would also expect that TDG supersaturation may occur if flows are partially shifted through the existing outlet works to enhance DO beyond what the applicant's proposed aeration basin would provide alone or if the project is shut down and all flows are released through the existing outlet works.

According to its Revised DOEP, the applicant plans to take an adaptive management approach to correct any deviations from state water quality criteria, including TDG levels that occur during operation. At this time, we are not aware of any additional potential measures that could be implemented at the project to minimize TDG levels; therefore, we assume that the project would be required to cease operation should TDG levels exceed the 110 percent saturation criteria stipulated by Montana DEQ's condition 4 similar to what would occur if DO criteria aren't met. Under a shutdown scenario, supersaturation of gases may occur at times during the summer and early fall as is typical under existing conditions until any future corrective actions are identified and implemented.

Although reduced turbulence in the tailrace area could benefit aquatic resources by reducing the frequency and extent of gas supersaturation, it could also decrease DO concentrations in the Beaverhead River by reducing the degree of aeration that occurs to water that is discharged downstream of the dam. Water currently discharges through the dam's outlet works under turbulent conditions, which tend to entrain atmospheric gases, thus increasing DO concentrations relative to Clark Canyon reservoir background levels. In contrast, discharging water through a powerhouse would reduce the turbulence and plunging effect and thus capacity for DO entrainment. The potential to pass water with decreased DO concentrations would be greatest in July, August, and September when DO concentrations at the bottom of the reservoir (near the depth of the intake) would be expected to be at the lowest levels of the year (

i.e.,

approaching 0 mg/L). Since baseline information indicates that DO levels in the upper Beaverhead River can fall below the 7.5-8.0 mg/L criteria for trout under existing aeration conditions, it appears likely that some level of DO enhancement would be necessary to ensure compliance with the state DO criteria during project operation.

Early life stages of trout begin to see declines in their growth rates when DO levels fall below 8 mg/L and cannot survive in extremely hypoxic conditions when DO levels fall below 1-3 mg/L (EPRI, 1990). Because baseline information indicates that DO levels in the upper Beaverhead River can at times fall below the 7.5-8.0 mg/L criteria in the summer months, providing the necessary aeration to achieve this criteria throughout the summer would enhance water quality and provide a benefit to aquatic resources during these months, particularly early life stages of trout that are typically more vulnerable to low DO levels (EPRI, 1990). Foust et al. (2008) determined that an air admission system is a particularly cost-effective method for improving DO conditions in a hydroelectric project tailrace and EPRI (2002) states that tailrace diffusers are widely accepted as devices capable of providing supplemental aeration. A similar aeration basin and diffuser array was built and operating effectively at the Island Park Hydroelectric Project (FERC Project No. 2973) in Idaho. Water quality monitoring reports filed from 2001-2016 confirmed that the Island Park Hydroelectric Project was successful at meeting state DO standards of 7.0 mg/L approximately 99 percent of the time during that period.

Given the information available, we anticipate that using a similar aeration basin and tailrace diffuser array to inject air into the water column to provide at least 7.5 mg/L of DO as the applicant proposes would maintain DO concentrations downstream to support all life stages of trout even when source reservoir levels are approaching 0 mg/L. Shifting flows to the existing outlet structures as needed to either achieve a level of 8.0 mg/L or shutting the project down and passing all flows through Reclamation's outlet works would ensure that project operation does not degrade water quality conditions relative to existing conditions and ensure that the applicant complies with DO levels stipulated by Montana DEQ's condition 3 while operating. Diverting all flows through the existing project works in the event of a blower failure or during an emergency shutdown would further ensure that existing water quality conditions are maintained downstream consistent with Montana DFWP's recommendation.

See

annual water quality monitoring reports for the Island Park Hydroelectric Project (FERC Project No. 2973) filed on November 2, 2001; April 22, 2002; August 25, 2003; July 9, 2004; August 8, 2005; June 27, 2006; October 3, 2007; December 31, 2008; November 12, 2009; December 6, 2010; and March 16, 2016.

In regard to Montana DFWP's and Upper Missouri Waterkeeper's recommendations that the applicant evaluate the need for dam infrastructure alterations and/or changes in long-term operations to minimize downstream turbidity, we echo the applicant's reply comment that it wouldn't alter the depth of the reservoir intake, or the rate,

volume, or velocity of water withdrawn as these are determined solely by Reclamation. Therefore, we are not aware of what changes to dam infrastructure or operations would result from the recommended evaluation to be able to sufficiently evaluate this measure. The applicant already proposes to implement other soil and erosion control measures during construction (

i.e.,

implementing its ESCP and CWQMP) which should inform how construction of the proposed penstock and outlet works affects downstream turbidity. Given these measures and the restrictions listed above, it is unclear what additional water quality benefit would be gained by requiring the applicant to conduct the recommended evaluation.

Post-Construction Water Quality Monitoring

Montana DEQ's condition 1 stipulates that the applicant conduct water quality monitoring for temperature, DO, and TDG for a minimum of the first five years of project operation and each year thereafter while discharging from July through October, unless Montana DEQ determines that additional monitoring is not warranted based on a review of the monitoring results for the first five years of project operation. Condition 6 stipulates that the project shut down automatically if DO levels fall below Montana DEQ standards and that a second, redundant DO probe be deployed at site 3 to ensure compliance with DO criteria during project operation. Condition 6 also stipulates that in the event that automated alarms indicate that water quality standards may have been exceeded (

i.e.,

TDG or temperature criteria), that an on-call operator be required to arrive within 30 minutes to evaluate the causes of the non-compliance reading. Condition 11 stipulates that the applicant meet annually with all watershed stakeholders to discuss water quality monitoring efforts associated with project operation.

Montana DEQ clarified in a phone conversation with staff that “watershed stakeholders” includes state and federal agencies, non-governmental organizations, and any interested members of the public.

See

telephone record summary between FERC and Montana DEQ filed on June 9, 2016.

In its Revised DOEP, the applicant proposes to continuously monitor TDG, DO and water temperature for at least the first five years of project operation consistent with Montana DEQ's condition 1. The applicant would monitor DO and temperature at three sites and TDG at two sites during this initial monitoring period (table 4).

Table 4—Water Quality Monitoring During Operation

[Source: License application as modified by staff]

Parameter

Monitoring site

Frequency and duration

Temperature (°C)

1, 2, 3

Continuous for a minimum of first five years of project operation.

Dissolved Oxygen (mg/L and percent saturation)

1, 2, 3

Continuous for a minimum of first five years of project operation.

Total Dissolved Gas (percent saturation)

2, 3

Continuous for a minimum of first five years of project operation.

Notes:

°C—degrees Celsius; mg/L—milligram per liter.

Site 1 is small chamber located upstream of proposed turbines. Site 2 is located in the proposed aeration basin. Site 3 is located about 300 feet downstream of the project in the Beaverhead River.

Site 3 would also contain a second redundant probe to monitor DO levels in the Beaverhead River for the first year of project operation and then each year thereafter from June 1-September 14, subject to approval from Montana DEQ and Montana DFWP.

Temperature and DO levels of the intake water would be monitored by diverting small amounts of water from the project penstock upstream of the turbines into a small pressurized chamber containing a monitoring probe (Site 1) that would continuously transmit data to the powerhouse. Probes would also be deployed in the aeration basin (Site 2) and at a site approximately 300 feet downstream of the project in the Beaverhead River (Site 3). A second redundant probe to “double-check” DO concentrations would also be deployed at Site 3 consistent with Montana DEQ's condition 6 for the first monitoring year and then from June 1 through September 15 each year thereafter or until the DO criteria is met for 14 consecutive days without supplemental aeration, whichever date is later, subject to approval from Montana DEQ and Montana DFWP. The applicant also states that Montana DEQ or Montana DFWP can request to extended or shortened deployment of the redundant probe at Site 3 if necessary.

As discussed in section 3.3.2.2,

Water Quality Operation Effects,

blower controls would include a bypass that would allow full flows to be automatically routed through the existing cone valves in the event of an emergency shutdown, or if DO criteria cannot be met. If probes at Site 3 indicate that DO levels are lowering and approaching Montana DEQ's DO criteria, flows would gradually shift to the cone valves in the existing outlet works to provide additional aeration beyond what the aeration basin could provide alone. If either probe at Site 3 registers DO levels that fall below compliance levels, the project would automatically trip offline, and all water would be diverted through the cone valves consistent with Montana DEQ's condition 6.

In addition to the automatic shutdown procedures described above, a powerhouse operator would oversee compliance with Montana DEQ's water quality standards and would take action in the event of a non-compliance reading for temperature, TDG, or if only one of the probes at Site 3 indicate that DO criteria is not being met. The operator would visit the powerhouse at least once daily during all phases of operation and would determine the ability of the aeration basin to provide sufficient aeration. If a non-compliance reading for temperature or TDG occurs at Site 3 or if only one probe indicates non-compliance with DO criteria, the operator would immediately investigate and determine if corrective actions, such as shutting the project down, is warranted.

Whenever the operator is not at the powerhouse, a series of automated alarms would dispatch an on-call operator to the powerhouse within 30 minutes following a non-compliance reading consistent with the procedures stipulated by Montana DEQ's condition 6. If the operator is not able to reach the powerhouse for any reason, or if the cause of any noncompliance reading cannot be determined, the project would be manually shut down either at the powerhouse or remotely and all water would be diverted through the cone valves at the existing project works. Thus, the applicant states that whenever

compliance with state water quality standards for DO, TDG, and temperature cannot be met due to project operations, the project would be offline and all flows would be diverted through the existing project works until further corrective actions, in consultation with the agencies, could be identified and implemented.

Although water quality would be monitored continuously, the applicant proposes to log and store hourly data for reporting purposes and to submit annual monitoring reports to Reclamation, Montana DEQ, Montana DFWP, and FWS for review by March 1 for the prior calendar year.

The reports would include the raw data, identify any deviations from water quality criteria, and recommended actions to correct any deviations. At the end of the five-year monitoring period, the applicant would file a report that includes recommendations for any potential future monitoring, and identify which parameters, if any, should be monitored. The applicant's Revised DOEP states that monitoring of any parameter could be extended beyond the initial five-year monitoring period at the discretion of Montana DEQ following review of the five-year monitoring results. In addition, the applicant includes a provision in its Revised DOEP to notify Reclamation, Montana DEQ, and Montana DFWP within 24 hours of any deviation from water quality criteria.

The applicant agreed to send all post-construction annual water quality monitoring reports to FWS in addition to the other agencies in their reply comments filed on April 8, 2016.

Upper Missouri Waterkeeper recommends that the applicant tier operation of oxygen supplementation systems to ongoing monitoring of hypolimnion conditions in the reservoir to ensure the system in fact discharges water that achieves water quality standards and to consider immediate shutdown of diversions if water quality is shown through monitoring to be negatively affected downstream. In its reply comments, the applicant states that implementation of its Revised DOEP, which includes water quality monitoring compliance sites and corrective measures that would be taken, would ensure that adequate DO concentrations are maintained during project operation.

Upper Missouri Waterkeeper recommends that the applicant support ongoing studies evaluating turbidity and nutrient pollution events occurring in the project vicinity and to develop and implement an adaptive management plan that addresses these concerns based on the results of those studies. In its reply comments, the applicant states that the proposed project has no nexus to the upstream land-use practices and subsequent nutrient loading to the Clark Canyon Reservoir and that it is beyond their control to eliminate or mitigate water quality impacts manifest

This text is long and has been trimmed here. Open the source document for the complete record.

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.