Floodplain Statement of Findings for Remedial Action at the Uranium Mill Tailings Sites Located Near Maybell and Naturita, CO

DEPARTMENT OF ENERGY

Floodplain Statement of Findings for Remedial Action at the

Uranium Mill Tailings Sites Located Near Maybell and Naturita, CO

AGENCY: U.S. Department of Energy.

ACTION: Notice of Floodplain Statement of Findings.

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SUMMARY: This Floodplain Statement of Findings is prepared pursuant to

Executive Order 11990 and 10 CFR Part 1022, Compliance with Floodplain/

Wetlands Environmental Review Requirements. Under authority granted by

the Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978, the

Department of Energy (DOE) plans to clean up residual radioactive mill

tailings and other contaminated materials at the former uranium mill

tailings processing sites near Maybell and Naturita, Colorado.

Contaminated material occurs in the 100-year floodplains of rivers and

streams at and near these processing sites, and the 100-year floodplain

of the San Miguel River at the Naturita site is contaminated. Remedial

action activities to remove contaminated material would result in the

temporary disturbance of the 100-

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year floodplain. Contamination occurs along Johnson Wash and Lay Creek

at the Maybell site; these areas may qualify for supplemental standards

and would therefore remain mostly undisturbed.

Copies of the floodplain/wetlands assessments for the Maybell and

Naturita sites are available from: National Technical Information

Service, Department of Commerce, 5285 Port Royal Road, Springfield, VA

22161, (703) 487-4650.

FOR FURTHER INFORMATION ON THE NEPA PROCESS, CONTACT: Carol M.

Borgstrom, Director, Office of NEPA Oversight, EH-25, U.S. Department

of Energy, 1000 Independence Avenue, SW, Washington, D.C. 20585, (202)

586-4600 or 1-800-472-2756.

SUPPLEMENTARY INFORMATION:

Background

The Floodplain and Wetlands Involvement Notification for remedial

action in the floodplains and wetlands at the Maybell and Naturita

sites was published in the Federal Register in 1988 (53 FR 5033). The

final environmental assessments (EA) were published in 1994 and 1995

for the Maybell (DOE/EA-0347) and Naturita (DOE/EA-0464) sites. In

addition, the Finding of No Significant Impact (FONSI) for each of

these sites was signed. Floodplain/Wetlands Assessments were prepared

for each site and are attached to the EAs.

Project Descriptions

Maybell Site

The Maybell site is 25 miles (mi) west of the city of Craig, in a

rural area of Moffat County in northwestern Colorado. The Maybell site

was established by Trace Elements Corporation in 1955, and Umetco

assumed control in 1957. A total of 2.6 million tons of ore was

processed before the mill shut down in 1964. The tailings pile and most

of the surrounding land contaminated with windblown tailings are in

upland areas. However, water erosion has contaminated nearby Johnson

Wash and a portion of Lay Creek; approximately 61,000 cubic yards

(yd3) of contaminated material are in these two drainages.

Johnson Wash begins in the sagebrush and pinon-juniper dominated

land northeast of the Maybell site and extends south about 1.5 mi to

Lay Creek. The wash is ephemeral and dry much of the year except at two

springs that create a surface flow that floods 600 to 900 feet (ft) of

the wash. Heavily grazed riparian vegetation occurs along 1 mi of the

wash, indicating that ground water is near the surface. Most of Johnson

Wash traverses a steep-sided valley, and sagebrush and/or pinon-juniper

plant communities occur along its entire length.

Lay Creek is a meandering stream with a flat, broad floodplain. The

creek contains water all year; ground water discharge is the source of

this water during dry parts of the year.

Various species of aquatic plants form a dense growth along the

stream, while higher areas are dominated by black greasewood and big

sagebrush. The area is heavily grazed by sheep and cattle.

The proposed action at the Maybell site is to stabilize the

contaminated material in place at the existing tailings pile. In

addition, a supplemental standards application will be prepared for

most of the contaminated areas along Johnson Wash and Lay Creek. The

rationale for supplemental standards at these two drainages is based on

ecological, radiological, geomorphological, socioeconomic, and

engineering criteria (see the Floodplain/Wetlands Assessment for more

details). Two areas of contamination, totaling about 12 acres (ac),

will be cleaned up along Johnson Wash and Lay Creek; one is in the

upper portion of the wash, in the windblown contaminated area, and the

other is in the lower portion of the wash, near its confluence with Lay

Creek. Currently, additional radiological characterization is taking

place along Johnson Wash and Lay Creek to verify the levels of

contamination along these two drainages. These surveys may identify

additional areas that need to be cleaned up. At this time, it is

anticipated that any additional clean-up along Johnson Wash and Lay

Creek will be minimal and that most of these two drainages will

continue to qualify for supplemental standards. Land disturbed in the

100-year floodplains of Johnson Wash and Lay Creek would be

recontoured, covered with topsoil, and revegetated with native plant

species.

Alternatives considered include no action and clean-up of all the

contaminated material along Johnson Wash and Lay Creek. Implementation

of no action would not be consistent with UMTRCA and would not be

protective of human health and the environment since it would not meet

Environmental Protection Agency (EPA) standards (40 CFR 192). Clean-up

of all the contaminated material would cause more environmental harm

than good, given the occurrence of wetlands and other sensitive

habitats along these drainages and the relatively low levels of

contamination.

Naturita Site

The Naturita site is 2 mi northwest of the unincorporated town of

Naturita in Montrose County, Colorado. The Naturita mill site was

constructed in 1930. It became operational in 1939, when it was

modified for the recovery of vanadium. Uranium milling began in 1942

and continued until 1963, when the mill was shut down. The tailings

were removed from the site in 1979 for reprocessing at a facility in

the hills about 3 mi south of the site. There is an estimated 542,400

yd3 of contaminated material on 244 acres of land. Approximately

263,000 yd3 of this contaminated material covers 31 ac in the 100-

year floodplain of the San Miguel River.

The San Miguel River originates in the San Juan Mountains near

Telluride, Colorado, and joins the Dolores River 20 mi downstream from

the Naturita site. In the vicinity of the Naturita site, the river has

a drainage area of 1209 square miles. Flow in the river varies

seasonally with the average maximum and minimum flows of 2000 and 330

cubic feet per second. A vegetated riparian zone occurs along the river

with plant communities growing in distinct zones. The zone nearest the

river consists of vegetation growing on the frequently flooded rocky

bars; cottonwood and willow seedlings are common here. Further back and

a bit higher in elevation, thick growths of cottonwood and willow

saplings are typically encountered. Mature cottonwood stands frequent

higher terraces along the river and generally give way to upland plant

communities.

The proposed action is to remove the contaminated material from the

floodplain of the river and upland areas and stabilize it in an off-

site disposal cell. This clean-up effort will disturb 31 contaminated

acres in the 100-year floodplain of the river. The average depth of the

excavation in this area would be 3 ft. The removal of contaminated

material from the upper and lower mill yard terraces would increase the

width of the 100-year floodplain. Clean fill material would be

backfilled into excavated areas as the contaminated material is removed

to minimize any increase in the width of the 100-year floodplain. After

completion of remedial action, all disturbed areas would be recontoured

to promote surface drainage and the man-made upper and lower mill yard

terraces would be replaced with a gentle slope. As a result of this, it

is anticipated that the 100-year floodplain will increase from 31 to 38

ac after the completion of this work. The restoration

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of the floodplain following remedial action is not expected to affect

the path or flow regime of the San Miguel River. All disturbed areas

would be revegetated as soon as possible after completion of remedial

action to minimize erosion.

Alternatives considered were on-site stabilization of the

contaminated material, no action, and other off-site disposal sites.

The impacts to the 100-year floodplain would be the same as described

above for other off-site disposal locations. The disposal of the

contaminated material on-site would also result in the disturbance of

the 100-year floodplain as described for the proposed action. No action

would result in leaving the contaminated material in the floodplain of

the San Miguel River and would not result in a reduction in public

health effects. In addition, the contaminated material would continue

to be susceptible to erosion, particularly during periods of high

water, which could result in negative impacts to the environment. In

addition, no action would not be consistent with the intent of UMTRCA

and would not result in compliance with the EPA environmental

protection standards.

Findings

Maybell Site

Little of Johnson Wash and Lay Creek, would be disturbed if

supplemental standards were successfully applied to these areas. It is

likely that a supplemental standards application would be successful,

given that the areas are ecologically sensitive, are remote from human

habitation, and that they contain relatively low levels of

contamination.

The clean-up of contaminated material of Johnson Wash and Lay Creek

would provide a long-term benefit by preventing impacts to human health

and the environment. Potential impacts to the 100-year floodplain that

may result from the excavation of contaminated material from Johnson

Wash would be mitigated by the following measures:

Erosion control measures would be implemented to minimize

erosion during clean-up activities along Johnson Wash and Lay Creek.

The 12 ac of land within the 100-year floodplain of

Johnson Wash and Lay Creek that would be disturbed would be recontoured

and revegetated following the completion of remedial action.

The excavation of contaminated material from the floodplain of

Johnson Wash and Lay Creek is designed to conform to applicable federal

and state regulations. Permits required under these regulations will be

obtained before the start of remedial action. Wetlands along Johnson

Wash and Lay Creek have been delineated; the U.S. Army Corps of

Engineers (USACE) has agreed with this delineation. Consultation is

ongoing with other federal agencies, such as the U.S. Fish and Wildlife

Service (FWS) and Bureau of Land management (BLM), and with the state

of Colorado.

Based on the above, it was determined that the impacts to the

floodplain along Johnson Wash and Lay Creek would be insignificant.

Naturita Site

The clean-up of contaminated material from the floodplain of the

San Miguel River in the area of the Naturita site would be a long-term

benefit because of the reduction of impacts to potential human health

and the environment. Potential impacts due to excavation of

contaminated material from the floodplain of the San Miguel River would

be mitigated by the following measures.

All excavated areas would be backfilled with clean fill as

soon as clean-up was completed.

Riparian vegetation along the river not subject to

excavation would be left intact as much as possible to reduce river

velocities and associated erosion during flood events.

All excavated areas would be regraded to a gentle slope to

promote positive drainage.

The upper and lower mill yard terraces would be given a

gentle slope to promote positive drainage.

All areas would be revegetated as soon as possible

following clean-up to minimize erosion into the river.

The excavation of contaminated material from the floodplain of the

San Miguel River is designed to conform to applicable federal and state

regulations. Permits required under these regulations will be obtained

before the start of remedial action. Wetlands along the river have been

delineated, USACE has agreed with this delineation, and a 404 Permit is

being prepared. Consultation is ongoing with other federal agencies,

such as FWS and BLM, as well as with the state of Colorado and local

government agencies.

Based on the above, it was determined that the impacts to the

floodplain along the San Miguel River would be insignificant.

Issued at Albuquerque, New Mexico, on July 21, 1995.

W. John Arthur III,

Acting Assistant Manager for Environmental/Project Management.

[FR Doc. 95-27231 Filed 11-1-95; 8:45 am]

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