Endangered and Threatened Wildlife and Plants; Notice of Determination To Retain Endangered Status for the Bruneau Hot Springsnail in Southwestern Idaho Under the Endangered Species Act

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants; Notice of

Determination To Retain Endangered Status for the Bruneau Hot

Springsnail in Southwestern Idaho Under the Endangered Species Act

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of determination.

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SUMMARY: The U.S. Fish and Wildlife Service, in a court-ordered

reconsideration of the 1993 final listing decision, affirms its earlier

determination that listing the Bruneau Hot Springsnail (Pyrgulopsis

bruneauensis) as endangered is appropriate. Federal protection pursuant

to the Endangered Species Act of 1973 (Act), as amended, for the

Bruneau Hot Springsnail is thus continued. This species occurs only in

a complex of flowing thermal springs arising from a single source

aquifer along the Bruneau River in Owyhee County, Idaho. Bruneau Hot

Springsnails are not known to occur elsewhere and have not been located

outside of the thermal plumes of hot springs entering the Bruneau

River. The primary threat to this species is the reduction of thermal

spring habitats from agricultural-related ground water withdrawal/

pumping.

DATES: The effective date of this notice is June 17, 1998.

[[Page 32982]]

ADDRESSES: The complete file for this notice is available for

inspection, by appointment, during normal business hours at the Snake

River Basin Office, U.S. Fish and Wildlife Service, 1387 S. Vinnell

Way, Room 368, Boise, Idaho 83709.

FOR FURTHER INFORMATION CONTACT: Robert Ruesink at the above address,

208/378-5243.

SUPPLEMENTARY INFORMATION:

Background

This notice of determination is in response to a June 29, 1995,

U.S. Court of Appeals for the Ninth Circuit (Court) decision directing

the Service to reconsider the listing of the Bruneau Hot Springsnail

(Idaho Farm Bureau Federation v. Babbitt, 58 F.3d 1392 (1995)). In its

ruling, the Court directed the Service to provide the public with ``* *

* notice and a period in which to comment on the U.S. Geological

Survey's (USGS) * * *'' 1993 report and ``* * * also provide the public

with any other new information * * *'' the Service planned to consider.

The Court further stated that the public could submit any other

information relevant to determining whether the Bruneau Hot Springsnail

should continue to be listed as endangered. The following determination

is based on a review of all existing information used in the original

1993 listing rule, and new information received since that time,

including information contained in written comments received during

three public comment periods, totaling 218 days.

Current Status

Boys Malkin first collected the Bruneau Hot Springsnail in thermal

springflows at the Indian Bathtub in upper Hot Creek along the Bruneau

River in 1952 (Hershler 1990). The following year, W.F. Bar collected

additional specimens, which were sent to J.P. Morrison of the U.S.

National Museum in Washington, D.C. (now the National Museum of Natural

History) (Hershler 1990). Taylor (1982) pursued subsequent field and

laboratory studies of this species from 1959 through 1982. Based on

these studies, Taylor prepared a brief physiological and biological

description of the species and suggested the common name of the Bruneau

Hot Spring Snail. In 1990, Robert Hershler formally described the

species from type specimens collected from the Indian Bathtub in Hot

Creek, naming it Pyrgulopsis bruneauensis, with a new common name of

Bruneau Hot Springsnail (Hershler 1990).

Adult Bruneau Hot Springsnails have a small, globose to low-conic

shell reaching a length of 5.5 millimeters (mm) (0.22 inch (in.)) with

3.75 to 4.25 whorls. Fresh shells are thin, transparent, white-clear,

appearing black due to pigmentation (Hershler 1990). In addition to its

small size (less than 2.8 mm (0.11 in.) shell height), distinguishing

features include a verge (penis) with a small lobe bearing a single

distal glandular ridge and elongate, muscular filament. They are

dioecious (individuals are either male or female) and lay single round

to oval eggs on hard surfaces such as rock substrates or other snail

shells (Mladenka 1992).

The species occurs in flowing thermal (hot) springs and seeps with

water temperatures ranging from 15.7 deg. Celsius (C) (60.3 deg.

Fahrenheit (F)) to 36.9 deg. C (98.4 deg. F) ( Mladenka and Minshall

1996). The highest Bruneau Hot Springsnail densities (greater than 1000

individuals per square meter (m2) (100 per square foot

(ft\2\)) occur at temperatures ranging from 22.8 deg. C (73 deg. F) to

36.6 deg. C (98 deg. F) ( Mladenka and Minshall 1996). Bruneau Hot

Springsnails have not been located outside thermal plumes of hot

springs entering the Bruneau River. They occur in these habitats on the

exposed surfaces of various substrates, including rocks, gravel, sand,

mud, algal film and the underside of the water surface (Mladenka 1992).

However, during the winter period of cold ambient temperatures and

icing, Bruneau Hot Springsnails are most often located on the

undersides of outflow substrates, habitats least exposed to cold

temperatures (Mladenka 1992). In madicolous habitats (thin sheets of

water flowing over rock faces), the species has been found in water

depths less than 1 centimeter (cm) (0.39 in.). Current velocity is not

considered a significant factor limiting Bruneau Hot Springsnail

distribution, since they have been observed to inhabit nearly 100

percent of the available current regimes (Mladenka 1992). In a

September 1989 survey of 10 thermal springs in the vicinity of the Hot

Creek-Bruneau River confluence, the total number of Bruneau Hot

Springsnails per spring ranged from 1 to 17,319 (Mladenka 1992). The

species abundance fluctuates seasonally but is generally stable under

persistent springflow conditions (Mladenka 1992; Robinson, et al. 1992;

Royer and Minshall 1993; Varricchione and Minshall 1995; Varricchione

and Minshall 1996; Varricchione and Minshall 1997). Depending on site

conditions, abundance is influenced primarily by temperature, spring

discharge, and chlorophyll ratios (Mladenka 1992).

Based on the most recent survey in 1996, Bruneau Hot Springsnails

were found in 116 of 204 small, flowing thermal springs and seeps along

an approximately 8 kilometer (km) (5 mile (mi)) length of the Bruneau

River in southwestern Idaho (Mladenka and Minshall 1996). Surveys

conducted since 1991 indicate a general decline in the number of

occupied sites from a total of 130 occupied springs to the current 116

springs, representing a 10 percent decrease (Mladenka 1992, 1993;

Mladenka and Minshall 1996). The majority (n = 86) of occupied springs

are located upstream of the confluence of Hot Creek with the Bruneau

River (Mladenka and Minshall 1996). In 1996, Bruneau Hot Springsnail

occurred in an additional 10 spring sites at the confluence of Hot

Creek and 20 sites downstream (Mladenka and Minshall 1996). Since 1991,

the total number of thermal springs in the Bruneau River has decreased

by approximately 5 percent (from 214 to 204), the number of springs

occupied by Bruneau Hot Springsnails has decreased by 10 percent (from

130 to 116), and the total surface area of springs occupied by Bruneau

Hot Springsnails has decreased by 13 percent (from 496 to 430.2

m2 (5338.9 to 4630.7 ft2)) (Mladenka and Minshall

1996).

Total site area (including all thermal springs and seeps, occupied

and unoccupied by Bruneau Hot Springsnails) increased by 4.3 percent

from 1991 to 1996 (Mladenka and Minshall 1996). Most of this increase

was due to lower flows at one unoccupied spring site, resulting in more

exposure of thermal outflow area below Buckaroo Dam, downstream of the

majority of the occupied springs (Mladenka and Minshall 1996). Further

analysis of the total spring surface area shows that from 1991 through

1996, there was a 32 percent decrease at upper (above the confluence

with Hot Creek) occupied spring sites versus a 41 percent increase in

lower occupied springs (Mladenka and Minshall 1996). Most of the

thermal springs and seeps containing Bruneau Hot Springsnails are small

and occur mainly upstream of the confluence of Hot Creek with the

Bruneau River. From 1991 to 1996, the number of occupied sites

decreased 20 percent (107 to 86) upstream of the confluence of Hot

Creek with the Bruneau River, decreased 17 percent (12 to 10) at the

confluence, and increased 45 percent (11 to 20) downstream of the

confluence. Many of the thermal springs located in the downstream

section are unsuitable as habitat for the Bruneau

[[Page 32983]]

Hot Springsnail, due to high temperatures (greater than 37 deg. C

(98.6 deg. F)). Surveys completed by Mladenka and Minshall in 1993 and

1996 found the size of occupied sites ranged from 0.1 m2 (1

ft2) to 120 m2 (1291.9 ft2) in 1993

and from 0.02 m2 (0.22 ft2) to 84 m\2\ (904

ft\2\) in 1996 (Mladenka 1993; Mladenka and Minshall 1996).

Bruneau Hot Springsnails prefer areas of locally warm water.

Mladenka (1992) found, however, that there is a maximum thermal

tolerance limit of 35 deg.C (95 deg.F), and that few Bruneau Hot

Springsnails occurred in cooler springs, with minimum temperatures to

15.7 deg.C (60.3 deg.F). Springs with cooler minimum temperatures are

likely warmer in the summer (greater than 20 deg.C (68 deg.F)),

providing the species opportunities for increased growth and

reproduction (Mladenka 1992). Temperature extremes affect both

abundance and recruitment of Bruneau Hot Springsnails (Mladenka 1992).

Spring sites occupied by Bruneau Hot Springsnail are located

primarily above the high-water mark of the Bruneau River. Some of the

Bruneau Hot Springsnail colonies are separated by distances of less

than 1 meter (m) (3.28 feet (ft)) (Mladenka and Minshall 1996). The

Bureau of Land Management (BLM) measured spring outflow elevations at

12 thermal springs from November 1993 to December 1993 (J. David

Brunner, BLM, in litt. 1994). Due to time constraints, thermal springs

that were measured for elevations represented the upper and lower most

springs within the Bruneau River corridor, a few thermal springs in

between, and the Indian Bathtub spring. Spring elevations ranged from

803.7 m (2636.9 ft) to 815.7 m (2676.1 ft) (Brunner, in litt. 1994). Of

the 12 thermal springs measured, 2 were not occupied by Bruneau Hot

Springsnail. The Indian Bathtub (the type locality) occurs at an

elevation of 814.7 m (2672.9 ft) and the uppermost thermal spring site

occurs at 815.7 m (2676.61 ft).

The hot springs and seeps that occur along the Bruneau River are

outflows of the Bruneau Valley geothermal aquifer (Berenbrock 1993).

Based on studies conducted by Mladenka (1992) and Varricchione and

Minshall (1997), seasonal fluctuations in water discharge (flow over

rockfaces) and water temperatures occur at some occupied spring sites.

Discharge fluctuations correspond with pumping; lower flows in the late

spring to early fall when the need for pumping is greatest, and higher

flows during late fall to spring when the need for pumping is lowest.

Temperatures can affect Bruneau Hot Springsnail recruitment;

reproduction usually occurs between 20 deg. and 35 deg.C (68 deg. and

95 deg.F), but growth and reproduction is retarded at temperatures

cooler than 24 deg.C (75.2 deg.F) (Mladenka 1992).

The Indian Bathtub area (now covered with sediment) and most of the

thermal springs along the Bruneau River upstream of Hot Creek are on

lands administered by the BLM, while most Bruneau Hot Springsnail

habitats downstream of the Indian Bathtub and Hot Creek are on private

land.

The Indian Bathtub spring and its outflow, Hot Creek, represent the

type localities of the Bruneau Hot Springsnail. Taylor (1982) found

that the Bruneau Hot Springsnail population and its habitat at the Hot

Creek/Indian Bathtub spring site had been reduced by more than 90

percent from 1954 to 1981. Taylor (1982) noted in 1981 that the

remaining Bruneau Hot Springsnail population at the Indian Bathtub

spring occurred on vertical rock cliffs (rockface sites) protected from

flash flood events. Varricchione and Minshall (1997) found that ``The

rockface sites are probably more suitable for Bruneau Hot Springsnail

success * * *'' because they provide the necessary substrate for

reproduction. In 1964, spring discharge at the Indian Bathtub spring

was approximately 9,300 liters per minute (L/min) (2,400 gallons per

minute (gal/min)). By 1978, discharge had dropped to between 503.8 to

627.8 L/min (130 to 162 gal/min) (Young et al. 1979). By the summer of

1990, discharge was zero during the summer and early fall (Berenbrock

1993). Taylor (1982) speculated that this reduction in rockface seep

flows would leave the Bruneau Hot Springsnail vulnerable to the

occasional flash-flood events known to occur in the Hot Creek drainage.

Today, water from the Indian Bathtub sinks below the ground surface

and reemerges about 300 m (984.3 ft) below the bathtub area

(Varricchione and Minshall 1997). In 1991, a flash flood event occurred

sending large amounts of sediment into the Hot Creek drainage and

resulting in a 50 percent reduction in the size of the Indian Bathtub

(a portion of which is now covered by approximately 10 feet of

sediment) (Mladenka 1992). Rockface habitat in the immediate vicinity

of Indian Bathtub was also severely reduced and covered with sediment

during this and other flash flood events (Mladenka 1992). Ongoing

population monitoring studies indicate a lack of movement or

recruitment of Bruneau Hot Springsnails back to the original Hot Creek/

Indian Bathtub sites (Varricchione and Minshall 1997). Varricchione and

Minshall (1997) suggest several factors including unsuitable substrate

type (primarily silt and sand, with little to no available rockface

surfaces), weak migration abilities, fish predation, and a lack of an

upstream colonization that may have prevented the Bruneau Hot

Springsnails from returning to the upper Hot Creek and Indian Bathtub

sites. Visible spring discharge at the Indian Bathtub continues to be

low, ranging from 5.9 and 11 liters per second (0.21 and 0.39 cubic

feet per second) and is intermittent in most years (Varricchione and

Minshall 1997; Derrill J. Cowing, USGS, in litt. 1996).

The Bruneau Hot Springsnails appear to be opportunistic grazers

feeding upon algae and other periphyton in proportions similar to those

found in their habitat (Mladenka 1992). However, Bruneau Hot

Springsnail densities are lowest in areas of bright green algal mats,

while higher Bruneau Hot Springsnail densities occur where periphyton

communities are dominated by diatoms (Mladenka 1992). Diatoms may

provide a more nutritious food source than other food types and their

presence may explain higher snail densities in such areas (Gregory

1983; Mladenka 1992). Bruneau Hot Springsnails may select for general

food quality rather than selecting for individual food items. Mladenka

(1992) noted that fluctuations in Bruneau Hot Springsnail abundance

corresponded with changes in food quality based on chlorophyll content.

Sexual maturity can occur within 2 months, with a sex ratio

approximating 1:1. Reproduction occurs throughout the year except when

inhibited by high or low temperatures (Mladenka 1992). Reproduction

occurs at temperatures between 24 deg. to 35 deg.C (75.2 deg. to 95

deg.F) (Mladenka 1992). At sites affected by high ambient temperatures

during summer and early fall months, recruitment corresponds with

cooler periods. Sites with cooler ambient temperatures also exhibit

recruitment during the summer months. Bruneau Hot Springsnails use

``hard'' surfaces such as rock substrate to deposit their eggs, or they

may deposit eggs on other snail's shells when suitable substrates are

unavailable (Mladenka 1992).

Mladenka (1992) believed that some natural transfer of Bruneau Hot

Springsnails may occur among sites. The mechanisms for dispersal

possibly include waterfowl passively carrying Bruneau Hot Springsnails

up or down the river corridor and spates (a sudden overflow of water

resulting from a downpour of rain or melting of snow) in the Bruneau

River that would carry Bruneau Hot Springsnails into other warm spring

areas downstream. Thus,

[[Page 32984]]

dispersal would favor upstream to downstream genetic exchange (Mladenka

1992).

Common aquatic community associates of the Bruneau Hot Springsnail

include three molluscs, Physella gyrina, Fossaria exigua, and Gyraulus

vermicularis; the creeping water bug (Ambrysus mormon minor); and the

skiff beetle (Hydroscapha natans) (Bowler and Olmstead 1991). In

addition, Hot Creek and several of the thermal springs along the

Bruneau River support populations of exotic guppies, (Poecilia

reticulata and Tilapia sp.). Guppies were apparently originally

released into upper Hot Creek at the Indian Bathtub, from which they

spread downstream and into nearby thermal springs and seeps along the

Bruneau River (Bowler and Olmstead 1991).

The Bruneau study area, delineated by Berenbrock (1993), was

purposely limited geographically to focus on the hydrology of the

regional geothermal aquifer system where the effects of pumping on

thermal springs discharge may be occurring. Specifically, the USGS

implemented a study of the geohydrology of the Bruneau area, including

ground water recharge, discharge, movement and hydraulic head; and

determined the effects of ground water pumping on hydraulic heads and

spring flows that could affect the Bruneau Hot Springsnail and its

habitat. Thermal spring habitats of the Bruneau Hot Springsnail are

formed as a result of water discharging from faults or fractures

originating from the underlying, confined volcanic-rock (geothermal)

aquifer (Berenbrock 1993). These natural, artesian vents discharge at

the ground surface where the ground surface level or elevation is lower

than the potentiometric or hydraulic head of the geothermal aquifer.

Berenbrock (1993) has developed a conceptual model of the geothermal

aquifer system that characterizes the geohydrology of the aquifer

system in the Bruneau study area. Using both direct and indirect

evidence, the model describes the hydraulic connection between the

large aquifer system underlying the Bruneau study area and the series

of thermal springflows along the Bruneau River containing Bruneau Hot

Springsnails. The 1554 square kilometer (km\2\) (600 square mile

(mi\2\)) Bruneau study area encompasses the Bruneau, Little and Sugar

valleys in north-central Owyhee County and is underlain with

hydraulically connected sedimentary and volcanic rocks that together

form a regional geothermal aquifer.

In general, ground water in the geothermal aquifer originates from

natural recharge from precipitation in and around the Jarbidge and

Owyhee mountains south of the Bruneau study area (Young and Lewis 1982,

Mink 1984). Ground water flows northward from volcanic rocks to

sedimentary rocks where it is discharged as either natural springflow,

ground water well withdrawals, or leaves the area as underflow

(Berenbrock 1993). Natural recharge to the regional geothermal aquifer

underlying the 1554 km\2\ (600 mi\2\) Bruneau area was estimated to be

approximately 70,281 cubic dekameters (dam\3\) (57,000 acre-feet (ac-

ft)) (Berenbrock 1993). Prior to extensive ground water development,

approximately 12,453 dam\3\ (10,100 ac-ft) was discharged from

springflows. The estimated recharge amount is a minimum value because

10 percent of the contributing area was not estimated due to inadequate

data being available (Berenbrock 1993).

Ground water withdrawals from wells for domestic and agricultural

purposes began during the late 1890's (Berenbrock 1993). From 1890 to

1978, well discharge increased from zero to approximately 50,059.8

dam\3\ (49,900 ac-ft) per year. Changes in discharge from thermal

springs corresponds with changes in hydraulic head, which fluctuate

seasonally and are substantially less during late summer than in the

spring (Berenbrock 1993). Water in the volcanic-rock in the northern

part of the study area near Hot Creek is confined by the overlying

sedimentary rocks, with temperatures at the surface ranging from 15

deg.C to more than 80 deg.C (59 to 176 deg.F) (Young et al. 1979).

Berenbrock (1993) described both the geothermal aquifer as well as

a shallow, unconfined cold-water aquifer within the upper layer of

sedimentary rock. This ``second'' aquifer system is recharged from the

infiltration of precipitation, streamflow, and applied irrigation

water. Both Mink (1984) and Berenbrock (1993) indicated that there may

be recharge from upward-moving geothermal water into the cold-water

aquifer. Mink (1984) also believes that additional recharge to the

shallow water aquifer may be occurring through leaks in irrigation

wells. Mink (1984) believed that leaks from uncased or poorly cased

wells were an additional reduction in water levels in the geothermal

aquifer.

Previous Federal Actions

Dr. Dwight Taylor carried out a field survey of the status of the

Bruneau Hot Springsnail in 1981 and 1982. His status report, received

by the Service on November 3, 1982, was the basis for the placement of

this species on the Service's comprehensive notice of review on

invertebrate candidate species published in the Federal Register (49 FR

21664) on May 22, 1984. A candidate species is a species for which the

Service has substantial information on hand to support the biological

appropriateness of proposing to list as endangered or threatened. The

Service first proposed the Bruneau Hot Springsnail for listing as

endangered on August 21, 1985 (50 FR 33803). The comment period on this

proposal, which originally closed on October 21, 1985, was extended to

December 31, 1985 (50 FR 45443). To accommodate public hearings in

Boise and Bruneau, Idaho, the comment period was reopened until

February 1, 1986 (50 FR 51894). At the time of the hearings and

subsequently, the Idaho Department of Water Resources (IDWR) and others

questioned the Service's analysis of available scientific information.

In particular, IDWR believed that surveys of available habitat were

incomplete and the analysis of human induced impacts, such as pumping,

was erroneous. To address these concerns and to solicit additional

information, on December 30, 1986, the Service reopened the public

comment period until February 6, 1987 (51 FR 47033).

Following the extension of the comment period in which the IDWR

proposed additional biological and hydrological studies in the Bruneau-

Grandview area, a decision was agreed upon by two former Idaho U.S.

Senators and the Service to develop a multi-agency cooperative

conservation plan for the Bruneau Hot Springsnail. In 1987, the U.S.

Congress appropriated additional monies to the Service to fund these

studies. Information developed from these studies was to be used to

develop a cooperative conservation (management) plan to conserve and

protect the Bruneau Hot Springsnail, precluding the need to list the

species under the Act. Three agencies conducted these studies: IDWR,

USGS, and Idaho State University (ISU). The IDWR was funded to: (1)

prepare a Geographic Information System for the study area to provide a

detailed information base from which to derive management decisions,

including existing data and data to be developed by USGS and ISU; (2)

prepare geological maps to define the bedrock geology and record the

location, elevation, flow and temperature of area springflows; and (3)

evaluate and analyze Federal and State laws applicable to a

conservation plan for Bruneau Hot Springsnails and assess management

alternatives open to the IDWR to protect Bruneau Hot Springsnail

habitats. The USGS was

[[Page 32985]]

funded to develop and implement a three-phase ground water study of the

Bruneau River valley and basin. The study focused on describing the

hydrology of the regional geothermal aquifer system and associated

thermal springs, with an overall goal to determine the cause of

declining springflows affecting the Bruneau Hot Springsnail and its

habitat. Finally, funds were provided to ISU to study the biological,

ecological, and physiological needs of the Bruneau Hot Springsnail.

The Service entered into a short-term conservation easement with

Owen Ranches, Inc., landowners of the Bruneau Hot Springsnail's habitat

in Indian Bathtub spring. The conservation agreement included fencing,

through funds provided by the Service, to regulate livestock use and

improve stream conditions. Although the agreement expired in October

1992, the current landowner has honored the terms of the agreement and

voluntarily excludes livestock grazing from the Indian Bathtub spring.

On July 6, 1992, the Idaho Conservation League and the Committee

for Idaho's High Desert filed a lawsuit over the failure of the Service

to make a determination and publish in the Federal Register a decision

regarding the listing of the Bruneau Hot Springsnail. To respond to the

lawsuit, and to ensure the accuracy of any final decision concerning

the appropriateness of listing, the Service reopened the public comment

period to solicit any new information on October 5, 1992 (57 FR 45762),

for a period of 30 days, and on December 18, 1992 (57 FR 60610), for a

period of 10 days.

A final rule listing the Bruneau Hot Springsnail as endangered,

without critical habitat, was published in the Federal Register on

January 25, 1993 (58 FR 5938). On February 26, 1993, the Idaho Farm

Bureau Federation, Owyhee County Farm Bureau, Idaho Cattle Association,

Owyhee County Cattleman's Association and Owyhee County Board Of

Commissioners (Plaintiffs), jointly filed a Notice of Intent to

challenge the listing. On May 7, 1993, the Plaintiffs filed a Complaint

for Declaratory and Injunctive Relief in the U.S. District Court for

the District of Idaho to overturn the final listing rule. On December

14, 1993, Senior United States District Court Judge Harold L. Ryan

issued a ruling in favor of the Plaintiffs and set aside the final

listing rule (Judgment) for the Bruneau Hot Springsnail (Civil No. 93-

0168-E-HLR). In the Judgment, Judge Ryan stated that the Service

committed ``* * * serious due process violations * * *'' and ``* * *

court finds the final rule to be arbitrary, capricious, an abuse of

discretion, and otherwise not in accordance with law.''

The district court decision was appealed to the United States Court

of Appeals for the Ninth Circuit by two intervening conservation

groups, the Idaho Conservation League and Committee for Idaho's High

Desert. On June 29, 1995, the appellate court overturned the district

court decision and reinstated the Bruneau Hot Springsnail to the

endangered species list. However, the appellate court concluded that

the Service should have made the draft USGS report (i.e., Berenbrock

1992) available for public review, as the Service relied largely on

this report to support the final listing rule. The appellate court

directed the Service to provide an opportunity for additional public

comment on the final USGS report (Berenbrock 1993) and other new

information, and to reconsider its original 1993 listing decision.

To comply with the appellate court's direction, the Service

published a notice on September 12, 1995 (60 FR 47339), announcing that

the USGS report (Berenbrock 1993), and other reports and data

pertaining to the listing of the Bruneau Hot Springsnail were available

for public comment for 60 days, until November 13, 1995. In response to

a request from Susan E. Buxton on behalf of her client (John B.

Urquidi, J & J Ranches, Bruneau, Idaho), the Service, in a notice

published on November 13, 1995 (60 FR 56976), extended the public

comment period until December 15, 1995. Over 400 comments were received

from individuals and agencies during this 95-day public comment period.

Public Law 104-6 enacted by Congress on April 10, 1995, placed a

moratorium on the expenditure of the Service's listing funds beginning

in October 1995 that remained in effect until April 26, 1996, when

President Clinton approved the Omnibus Reconciliation Act of 1996. As a

result, the Service was unable to comply with the June 1995 court

decision and complete a reconsidered listing decision. After the

moratorium was lifted, the Service established priorities for

completing listing actions based on interim guidance issued on March

11, 1996 (61 FR 9651), final guidance for fiscal year 1996 on May 16,

1996 (61 FR 24722), and final guidance for fiscal year 1997 issued on

December 5, 1996 (61 FR 64475). These guidance documents focused the

Service's limited listing funding on emergency listing and multi-

species final rules. Consequently, the Service took no action on the

Bruneau Hot Springsnail during fiscal year 1996. Although listing

priorities allowed the Service to take final action on this court

decision beginning in fiscal year 1997, it had been over one year since

the close of the last public comment period. Therefore, the Service

solicited additional comments and made available for public review new

information and other data pertaining to the Bruneau Hot Springsnail

received since the last comment period. On January 23, 1997 (62 FR

3493), the Service opened a second public comment period for 46 days

until March 10, 1997. Because of requests from the High Desert

Coalition Inc., Bruneau Valley Coalition and Quey Johns, the Service

opened a third public comment period, for an additional 77 days, until

June 9, 1997, in a notice published on March 25, 1997 (62 FR 14101).

Fifteen comments were received from individuals and agencies during

these two additional comment periods in 1997. In total, 416 comments

were received between September 1995 and June 1997 during 3 public

comment periods.

Summary of Comments and Recommendations

Comments were received from 416 individuals and agencies during the

3 public comment periods from September 1995 to June 1997 (60 FR 47339,

60 FR 56976, 62 FR 3493, 62 FR 14101) for a total of 218 days.

Additionally, advance notice of re-opening the comment periods was

given to several people by telephone for the January and March 1997

comment periods. Persons notified represented various interested

parties in this issue including; Dick Bass, Owyhee County Commissioner;

Tim Lowry, Chair of the Owyhee County Land Use Planning Committee

(OCLUPC); Cindy Bachman, Chair of the Endangered Species Subcommittee

for the OCLUPC; Eric Davis, President of the Bruneau Valley Coalition;

and Laird Lucas, Land and Water Fund. Advance notice, including a press

release and background information, was also sent by mail, fax and/or

phone to Idaho Senators Larry Craig and Dirk Kempthorne, Idaho

Representatives Mike Crapo and Helen Chenoweth, Idaho State Senator

Laird Noh, and Idaho State Representative Golden Longhaired. Legal

notices announcing each of the public comment periods were published in

five Idaho newspapers: Idaho Statesman, Boise; Glenns Ferry Pilot,

Glenns Ferry; Idaho Press Tribune, Nampa; Owyhee Avalanche, Homedale;

and Mountain Home News, Mountain Home. Fifty-three copies of the

Federal Register notices of public comment periods were

[[Page 32986]]

sent to various interested parties, including 7 Federal agencies, the

8-member Idaho Water Resources Board, IDWR, Idaho Department of Fish

and Game (IDFG), Idaho Department of Parks and Recreation (IDPR), ISU,

the Idaho Congressional delegation, Governor Phillip Batt, State of

Idaho elected officials including State Representatives Frances Field

and Golden Longhaired and State Senators Laird Noh and R. Clair

Wetherell, Elmore and Owyhee County Commissioners and 19 other

individuals.

The majority of the comments opposed endangered species status for

the Bruneau Hot Springsnail--of the dissenting comments, 349 comment

letters were derived from the same source (i.e., a form letter)

received during the first re-opened comment period in September 1995

and were considered together as one comment. Comments opposed to

endangered species status were received from Idaho Governor Philip

Batt, Idaho State Senator Grant Ipsen, IDWR, the Office of the State

Treasurer, the Owyhee County Board of Commissioners, OCLUPC, and other

user groups. No request for a public hearing was received.

Comments of a similar nature or point of concern are grouped for

consideration and response. A summary of these issues and the Service's

response to each are discussed below.

Issue 1: Several respondents believe that the range of the Bruneau

Hot Springsnail is not completely known. They stated that comprehensive

surveys have not been conducted throughout all potentially suitable

habitat in the region and one study (Mladenka 1995) surveyed fewer

sites than previous surveys. Because it is believed that the Bruneau

Hot Springsnail has stabilized (based on studies from 1992 through

1996) or appears to be increasing in certain areas, some respondents

stated that the species is not truly endangered. Also, some respondents

believe that the fish predation study was inadequate to determine if

fish predation is a threat to the Bruneau Hot Springsnail. It is also

believed that Bruneau Hot Springsnails are highly adaptable and can

easily relocate. For example, a colony is being kept in an aquarium at

the BLM, Boise District office indicating that the species may be

adaptable to environments outside their thermal spring habitats in the

Bruneau River.

Service Response: Snail surveys have been conducted in Idaho and

elsewhere since 1994 (Frest, in litt. 1994; Frest and Johannes 1995;

Robert Hershler, Smithsonian Institution, in litt. 1994, 1995). Surveys

included regions within the Great Basin, including Utah, Nevada and

eastern Idaho, and the Interior Columbia Basin. Thermal springs along

the Bruneau River have been re-surveyed specifically for additional

Bruneau Hot Springsnail sites in 1993 and 1996 (Mladenka and Minshall

1993, 1996). No other new information has been presented to the Service

to substantiate the claim that the Bruneau Hot Springsnail is not

endemic to springs along Hot Creek and the Bruneau River drainage. No

historic collections of this species have been verified in other areas

of the United States. In 1991, Mladenka (Mladenka 1992) described the

known range of the Bruneau Hot Springsnail as an 8 km (5 mi) reach of

the Bruneau River, above and below the confluence of Hot Creek. Other

studies outside the Bruneau River corridor (Terrence J. Frest, DEXIS,

in litt. 1994; Frest and Johannes 1995; Hershler in litt. 1994, 1995)

have not located additional sites for the Bruneau Hot Springsnail.

Studies conducted by Mladenka (1992) and Mladenka and Minshall

(1993; 1996) indicate a general decline in the total number of thermal

springs along the Bruneau River, the number of springs occupied by

Bruneau Hot Springsnails and a general decline in densities of Bruneau

Hot Springsnails (see BACKGROUND section for further discussion).

Mladenka and Minshall (1993) found dead Bruneau Hot Springsnails at one

previously occupied spring site where flows had recently diminished and

nine additional spring sites showed noticeable reductions in discharge.

From 1991 to 1996, the total number of springs had been reduced from

214 to 204. The number of springs occupied by Bruneau Hot Springsnails

had declined from 130 to 116. Additionally, although Mladenka and

Minshall's (1993; 1996) population densities were only estimates, there

appears to be a trend in declining densities overall that corresponds

to the decline in the number of occupied spring sites.

While two of the three populations of the Bruneau Hot Springsnail

monitored since 1991 appear to be stable (Varricchione and Minshall

1997), the Service believes that all remaining habitat for this species

is threatened by those factors described in this rule (Factors A and E,

Summary of Factors Affecting the Species). Given that all thermal

springs along this reach of the Bruneau River arise from a single

regional geothermal aquifer (Berenbrock 1993), Bruneau Hot Springsnails

and their habitats continue to be threatened by long-term declines in

the Bruneau Valley aquifer. The Bruneau Hot Springsnail, endemic to

this small geographic area in southwestern Idaho, and its habitat are

totally dependent on remaining thermal springflows originating from

this single source of ground water. As noted by Varricchione and

Minshall (1997), ``Given enough reduction in springflow, Bruneau Hot

Springsnail populations (at the two monitored sites) could be reduced

to abundances that are too small to remain viable.''

Regarding the comment that Mladenka's 1995 survey study looked at

fewer sites than previous surveys, the purpose of the study was to

survey the macroinvertebrate assemblages in several thermal springs

along the Bruneau River in the vicinity of its confluence with Hot

Creek. The Service funded this study to further define the species

richness of the thermal springs occupied by the Bruneau Hot

Springsnail. Due to the replication of species found in several of the

initial hot springs sampled, the Service made a decision that sampling

fewer sites would be representative of all thermal springs along the

Bruneau River. This study, therefore, was not strictly a Bruneau Hot

Springsnail survey.

A study to determine the effects of fish predation on the Bruneau

Hot Springsnail was conducted by Varricchione and Minshall (1995a). The

study focused on two exotic species of fish, Gambusia and Tilapia, in

the Hot Creek drainage. Hot Creek no longer has a viable population of

Bruneau Hot Springsnails (too few in total numbers of individuals), and

no Bruneau Hot Springsnails were detected in the diet of these two

species of fish (Varricchione and Minshall 1995a). Mladenka (1992)

however, found Gambusia aggressively preying upon Bruneau Hot

Springsnails in a controlled (aquarium) environment. Additionally, a

commenter indicated that the time of year that the fish predation study

was undertaken was inappropriate since water temperatures may have been

too cold and Bruneau Hot Springsnails are less available during winter

conditions. The fish predation study was undertaken during the winter

months, which for the Hot Creek site is the optimal time for

reproduction and recruitment of Bruneau Hot Springsnails. Water

temperatures in the summer reach or exceed the thermal maximum

temperature due to exposure to higher ambient temperatures

(Varricchione and Minshall 1997). During periods of higher

temperatures, the species retreats to areas protected from high ambient

temperatures among sedges, underneath rocks or under superficial algal

mats (Mladenka 1992). Pending further study,

[[Page 32987]]

the Service considers the presence of these two exotic fishes a

possible threat to Bruneau Hot Springsnails residing in Hot Creek and

at other thermal spring sites along the Bruneau River.

Bruneau Hot Springsnails may be limited in their ability to

relocate and re-colonize new spring sites. The parameters required for

acceptable habitat are specific in nature, i.e. minimum and maximum

temperatures of 7.6 and 35.7 deg. C (45 and 96 deg. F) respectively and

adequate substrate and spring discharge (Varricchione and Minshall

1997). Mladenka (1992) found that reproduction occurred at temperatures

between 20 and 35 deg. C (68 and 95 deg. F), with a noted decline in

reproduction (and hence recruitment) at 24 deg. C (75.2 deg. F). Few

springs along the Bruneau River meet these requirements. Mladenka

(1992) indicated that dispersal likely occurs through spates within the

Bruneau River corridor.

Since approximately 1985, the BLM has maintained a population of

Bruneau Hot Springsnails in an aquarium. The environment is being

artificially maintained using an aquarium heating device and periodic

additions of distilled water, with occasional augmentations of water

from Hot Creek. Due to the regular maintenance required of this system,

the Service does not consider this population a viable and sustainable

population under the definition of recovery for endangered species.

Issue 2: Many respondents believe that the Service did not use the

best or sufficient scientific information in listing this species.

Other comments indicated that few sites have been surveyed for the

presence of the Bruneau Hot Springsnail and that the surveys were

biased against farming and ranching. Other concerns were that

monitoring has not been adequate to assess the status of the species.

Many respondents believe that this species is widespread and additional

populations exist elsewhere that have not been reported. Several

respondents also stated that because Bruneau Hot Springsnail

populations are stable or increasing at some sites, listing is not

appropriate. One commenter indicated that because monitoring was

terminated in 1993, data collected subsequently was not reliable.

Service Response: The Service believes that the decision to retain

the Bruneau Hot Springsnail as endangered is based on the best

available scientific information. The Service is unaware of any bias on

the part of the researchers involved in biological or ground water

studies. The Service believes that all research has been conducted in a

professional and credible scientific manner.

Ground water studies conducted by the USGS, funded by the Service

beginning in 1989, with monitoring of water levels, spring discharge

and pumping rates continuing until September 1996. Biological surveys

and monitoring for the Bruneau Hot Springsnail, funded by the BLM and

the Service, have been ongoing through ISU from 1991 through 1996.

Although Bruneau Hot Springsnails have been located at new thermal

spring sites, all these sites are within the known range of the

species, an 8 km (5 mi) reach of the Bruneau River (Mladenka and

Minshall 1993, 1996) and all these thermal springs are subject to

similar threats affecting the single source geothermal aquifer

providing the necessary springflows. It has been documented that from

1992 to 1996, there has been an overall reduction in the number of

thermal springs along the Bruneau River; the number of thermal spring

sites occupied by Bruneau Hot Springsnails; and a reduction in the

overall densities of Bruneau Hot Springsnails at the known occupied

sites (see BACKGROUND section and issue #1 for further discussion). As

already discussed, thermal springs along the Bruneau River are

influenced by activities affecting the condition of a single geothermal

aquifer. The decision to continue the listing of the Bruneau Hot

Springsnail is appropriate based primarily on continued habitat loss

and modification resulting from reduced thermal springflows.

As previously stated in the issue #1 response, snail surveys have

been conducted in Idaho and elsewhere since 1994 (Frest, in litt. 1994;

Frest and Johannes 1995; Hershler, in litt. 1994, 1995). These surveys

included regions within the Great Basin, including Utah, Nevada and

eastern Idaho, and the Interior Columbia Basin. Thermal springs along

the Bruneau River have been re-surveyed specifically for additional

Bruneau Hot Springsnail sites in 1993 and 1996 (Mladenka and Minshall

1993, 1996). No other new information has been presented to the Service

to substantiate the claim that the Bruneau Hot Springsnail is not

endemic to springs along Hot Creek and the Bruneau River drainage. No

historic collections of this species have been verified in other areas

of the United States. The Bruneau Hot Springsnail is part of a small

group of thermophile species (requiring high temperatures for normal

development), most or all of which are highly endemic (Frest and

Johannes 1995). In addition, most taxa in the Pyrgulopsis genus are

endemic to a single spring or spring groups widely separated from each

other geographically (Frest and Johannes 1995).

In regard to the comment about an abrupt halt to monitoring efforts

* * * ``In light of Mr. Lobdell's abrupt termination of the 1992 data

collection for the (Bruneau Hot Springsnail), reliance on the ISU

Stream Ecology Center Studies--all referencing the 1992 data gathering

activities--are suspect.'', the Service believes this refers to a brief

halt in 1992-1993 data gathering as a result of the 1993 listing of the

Bruneau Hot Springsnail, at which time the species was given the full

protection of the Act. The Service issues permits to individuals

wishing to conduct research to further the recovery of the species.

Once the necessary permitting requirements under section 10 of the Act

were satisfied, data collection for the 1992-1993 season continued and

was completed. The Service is satisfied with the reliability of the

data.

Issue 3: Some respondents believed that the Bruneau Hot Springsnail

is not native or does not appear to have any ecological significance

and therefore should not be listed.

Service Response: Congress directed that, in determining whether a

species warrants listing under the Act, the Service may consider only

the five factors set forth in section 4(a)(1) of the Act. These factors

do not include the ``ecological significance'' of the species; hence,

the Service has no authority to decline to list a species on the basis

of whether or not the species is considered ecologically significant.

Issue 4: Many respondents believe that the hydrologic studies

conducted to date are inconclusive with regard to determining that

water withdrawals cause the decline in the geothermal aquifer. Many

noted that the 1993 USGS report (Berenbrock 1993) is incorrect or

incomplete because it does not account for the effects of climatic

(e.g., drought) or geologic factors that may be affecting springflow

and well discharge characteristics and Bruneau Hot Springsnail

population estimates, even accounting for the significant reductions in

pumping in recent years. Recent reports (Cowing, in litt. 1996; Karl J.

Dreher, IDWR, in litt. 1997) indicate that water levels in the aquifer

have increased. It was also suggested that studies on the dynamics of

the local aquifer system should be subject to independent peer-review.

Many respondents believe that the recharge calculation error found in

the draft USGS report (Berenbrock 1992) is still unresolved and should

be corrected

[[Page 32988]]

before further assessment of the aquifer can occur.

Service Response: Berenbrock (1993) indicated that water levels and

spring discharge were likely not related to recent climatic (drought)

conditions. It has been established that recharge to the aquifer is

related to precipitation in the Jarbidge Mountain range (Berenbrock

1993). The effect of this recharge is over several thousand years, as

evidenced by the age of the water currently residing in the aquifer.

Although the amount of withdrawals has been reduced since 1981, from

61,526.7 dam3 (49,900 ac-ft) to a low of 40,935.6

dam3 (33,200 ac-ft) in 1987 (1995 levels were 45,374.4

dam3 (36,500 ac-ft)), spring discharge and available Bruneau

Hot Springsnail habitat have continued to decline (Cowing, in litt.

1996). Berenbrock (1993) calculated natural recharge to the geothermal

aquifer to be 70,281 dam3 (57,000 ac-ft) (Berenbrock 1993).

This value does not account for the underflow (recharge) drained by the

Little Jacks and Logan creeks, which represents 10 percent of the

contributing area. Therefore, the natural recharge estimated by

Berenbrock (1993) is a minimum value only. Total estimated discharge

from springs prior to extensive ground water development was

approximately 12,453 dam3 (10,100 ac-ft). Between 1978 and

1991 total well withdrawals were 673,218 dam3 (546,000 ac-

ft), averaging 51,786 dam3 (42,000 ac-ft) per year.

The Service concurs with Berenbrock's (1993) conclusions and with

the results of the continued monitoring efforts by USGS through

September 1996 (Cowing, in litt. 1996). The conclusions reached by

Berenbrock and the monitoring data demonstrate a relationship between

water levels in the aquifer, seasonal variations in water levels,

spring discharge, and pumpage rates. Annual pumpage rates are related

to climatic conditions in the Bruneau Valley, i.e., well withdrawals

increase when spring precipitation is low. Spring discharge exhibits a

similar seasonality to water level measurements June through September,

reflecting the amount of pumping through the irrigation season (Cowing,

in litt. 1996). A relation between potentiometric levels and spring

discharge has persisted through the drought and into ``normal''

precipitation cycles. As indicated above, although ground water levels

may be depleted fairly rapidly by human utilization for agricultural or

other uses, the geothermal aquifer recharge typically occurs very

slowly and from a source well outside the Bruneau area (see Factor A of

the Summary of Factors Affecting the Species section for further

discussion). Therefore, although there was a slight increase in water

levels at some well monitoring sites in 1996, and a slight increase in

spring discharge at some springs monitored at the same time, the

general trend for Bruneau Hot Springsnail habitat remains in decline

and water levels in the geothermal aquifer are low when compared to

historic levels. Of the 19 wells within the Bruneau study area, 11

wells have continued to show slight declines in water levels, and 6

have shown slight increases in water levels (2 wells were difficult to

determine from graphs) (Cowing, in litt. 1996) . In general, water

levels in the geothermal aquifer continue to decline.

A relation between hydraulic head and spring discharge has been

established, the Service has not received any new information

indicating a change in this relation between total aquifer discharge

(including spring discharge, underflow and well withdrawals) and

recharge. The question of what levels of pumping can occur without

further declines in aquifer water levels and thermal spring flows has

not been defined.

The USGS report and document review process consists of a three-

step process: (1) local (originating office) review includes review by

2 district (Idaho) colleagues that are experts in the technical

information contained in the report, review by the section supervisor

and editorial review by an experienced editor; (2) regional USGS review

includes another specialist review by a technical expert in the

discipline of the report and a second editorial review; and (3) USGS

headquarters review involves a third technical reviewer and a third

editorial review. The final document is then signed by the Director of

the USGS. In the case of Berenbrock (1992), IDWR was provided a copy of

the draft document prior to the Service completing the original listing

rule. IDWR used the information in preparing their contractual report

submitted to the Service entitled ``Analysis of Management Alternatives

and Potential Impacts on Ground-Water Development Due to Proposed

Endangered Species Classification of The Bruneau Hot Springs Snail''

(IDWR 1992).

The recharge ``error'' referred to by comments relates to a

miscalculation of natural recharge using Darcy's equation in the draft

1992 Berenbrock report. The error in natural recharge occurred due to a

miscalculation in average hydraulic conductivity (Jerry Hughes, USGS,

in litt. 1993). The final (1993) version of the Berenbrock report

(pages 23 through 26) incorporates the correct information for

calculating natural recharge by another method. Therefore, the Service

believes that the issue of ``errors'' in the draft report has been

resolved.

Issue 5: Some respondents believed that there is no evidence that

reducing agricultural or domestic water use will actually benefit

Bruneau Hot Springsnail habitat. Other comments suggested that casing

deep wells to reduce leakage would contribute to water conservation and

reduce or remove the need to list this species. Two respondents

referred to the disappearance of ``Deer Water'' in Hot Creek (as an

indicator that declining water levels have occurred in the historic

past). It was also speculated that stabilization of the aquifer will

occur at some point in the future.

Service Response: The Service believes that on-going, unrestricted

ground water pumping has contributed to the loss of Bruneau Hot

Springsnail thermal spring habitats in the Bruneau River drainage.

Protection of the remaining Bruneau Hot Springsnail habitat can only be

achieved through cooperative efforts with the State of Idaho and

others, which address water levels within the geothermal aquifer and

the maintenance of thermal springflows.

It is recognized that the geothermal aquifer in the Bruneau Valley

is a complex, multi-layered aquifer, and that water leakage may occur

in a stepwise fashion upward between permeable zones through faults,

fractures, and wells (Kimball E. Goddard, USGS, in litt. 1995; IDWR

1992; Mink 1984; Leland R. Mink, IWRRI, in litt. 1995) (see BACKGROUND

section for further discussion). The ground water reservoir in the

aquifer functions as a three-dimensional flow system: (1) water flows

northward from the recharge area in the Jarbidge and Owyhee mountains,

where it is discharged as springs and as seepage to streams or leaves

the area as ground water underflow; (2) in recharge areas there is a

downward component of water movement; and (3) in discharge areas there

is an upward component (Berenbrock 1993). In 1984, the Idaho Water

Resources Research Institute (IWRRI), along with the University of

Idaho, proposed an investigation of geothermal wells to determine

whether older or uncased wells are losing water to the upper aquifer

and determine the feasibility and estimated cost of repairing those

wells (Mink and Lockwood 1995). Mink and Lockwood (1995) indicated that

Ron Hiddleston (drilling expert in Mountain Home) believed that ``* * *

there are very few properly constructed wells in the Bruneau Valley.''

Mink and Lockwood (1995) also found that Merion Kendall

[[Page 32989]]

(in 1989) estimated that 77 percent of the wells in the Bruneau area

had the potential for interaquifer flow. Mink and Lockwood (1995)

concluded that water is moving horizontally out of wells into

shallower, more permeable zones. It was not determined what volume of

water could be moved from the deeper aquifer (geothermal) to the

shallower aquifer (cold-water) system. In 1995, the Service provided

$2,500 to IWRRI to evaluate the cross-flow potential of individual

wells. It was not until the summer of 1997 that IWRRI was able to

obtain permission to investigate a single well. By the close of the

public comment period in June 1997, the Service had not received a

report from IWRRI on the results of their limited investigation. The

Service agrees with others (Goddard 1995; IDWR 1992; Mink 1984, Mink

and Lockwood 1995) who believe that leakage from some agricultural

wells may be a contributing factor in the loss of water from the

geothermal aquifer.

No information has been provided to the Service regarding the

specifics of the disappearance of ``Deer Water'' and there has been no

reference to ``Deer Water'' in previous studies. Therefore, the Service

is unaware of a prehistoric disappearance of ``Deer Water'' on Hot

Creek.

Although the Service agrees that ``stabilization'' of the aquifer

may occur some time in the future, it is uncertain that

``stabilization'' can occur before there is further loss of thermal

spring habitats. A relationship between hydraulic head and spring

discharge has been established; the Service has not received any new

information indicating a change in this relation between total aquifer

discharge (including spring discharge, underflow and well withdrawals)

and recharge. The question of what levels of pumping can occur without

further declines in aquifer water levels and thermal spring flows has

not, to our knowledge, been defined. If water levels in the geothermal

aquifer system in the Bruneau area continue to decline, the Service

believes that thermal springs will eventually cease to flow and Bruneau

Hot Springsnails and their habitat will be eliminated.

Issue 6: Many respondents stated that existing regulatory

mechanisms are sufficient to protect this species in lieu of listing.

For example, the Bruneau Valley Coalition has developed a habitat

conservation plan; the Governor of Idaho stated that ``as soon as the

bull trout conservation plan is complete, (he) will turn the State's

attention to developing a conservation plan for the (Bruneau Hot

Springsnail)'' (Phillip E. Batt, Governor of Idaho, in litt. 1995); and

the Idaho State Legislature has developed State law to prevent the

waste or ``mining'' of ground water (Dreher, in litt. 1997). Dreher (in

litt. 1997) asserted that water withdrawals have never exceeded

61,526.7 dam3 (49,900 ac-ft), which is below the natural

recharge calculated by USGS and therefore, concern for further loss of

thermal springs is probably not warranted. Many respondents believe

that listing the Bruneau Hot Springsnail would adversely affect local

and regional planning efforts that are currently in progress. For

example, the IDWR has designated the area as a Ground Water Management

Area (GWMA), which should provide protection for the aquifer and ensure

adequate flows for the Bruneau Hot Springsnail. IDWR has presented

alternatives to listing that would protect Bruneau Hot Springsnail

habitat and these alternatives have been incorporated into the Owyhee

County Land Use and Management Plan.

Service Response: IDWR can regulate ground water development in the

Bruneau area. Through this regulatory authority, IDWR may designate an

area as a GWMA if it has been determined that a ground water basin or

part thereof may be approaching the conditions of a ``critical ground

water area'' (I.C. 42-233a et seq.). Under this designation, the

Director of IDWR may approve applications for permits only after it is

determined that sufficient water is available (I.C. 42-233a et seq.).

In 1982, the IDWR established the Bruneau-Grandview area as a GWMA

(Dreher in litt. 1997). Since that time, no new water withdrawal

permits have been issued for agricultural use. The Director may also

determine whether or not a ground water supply is insufficient to meet

demand within a designated water management area and will order those

water rights holders on a time priority basis to cease or reduce

withdrawal of water until it is determined that there is sufficient

ground water (I.C. 42-233a et. seq.). The State of Idaho has determined

that a level of 61,526.7 dam3 (49,900 ac-ft) does not

constitute ``mining'' of ground water in the Bruneau-Grandview area.

This amount of withdrawal was reached in 1981 (Cowing, in litt. 1996).

Withdrawals have ranged from 56,471 to 40,935.6 dam3 (45,800

to 33,200 ac-ft), with an average amount of 45,390 dam3

(36,813 ac-ft) over a 13-year period from 1982 to 1995, excluding 1994

(Cowing, in litt. 1996). Although withdrawal rates have remained below

the 1981 level, aquifer levels continued to decline through 1994, with

only a slight increase in water levels occurring in early 1996. At this

time, pumping rates during the late 1996 to early 1997 irrigation

season are unknown. Pumping rates have been similar to 1995 levels due

to higher precipitation during the 1996 irrigation season. To date, the

State of Idaho has not taken any action to implement legislation

intended to control existing withdrawals (Dreher in litt. 1997).

In 1992, IDWR developed four management alternatives to preclude

the listing of the Bruneau Hot Springsnail. Three of the alternatives

were included by the Owyhee County Commissioners (OCC) in the Owyhee

County Interim Comprehensive Land Use and Management Plan (OCC 1993).

The preferred alternative by both IDWR and OCC was Alternative A, to

``Do Nothing.'' In support of Alternative A, IDWR (1992) stated that

``it is not reasonable to assume that all spring flows are declining or

that water levels will decline at the same rate as monitored springs

and wells.'' IDWR further stated that there are ``no data to support

how much of (the) decline (in spring flow) is related to the extended

drought in southern Idaho and how much might be related to ground water

withdrawals.'' IDWR also asserted that ``with the existing reduced

level of ground water withdrawal, due in large part to the Conservation

Reserve Program, aquifer water levels would normally be expected to

reduce their rate of decline if drought conditions were no longer

present.'' IDWR assumed that only those springs with elevations lower

than Indian Bathtub are being affected by reduced spring flows and that

at some point in the future, when the aquifer stabilizes, these springs

also will stabilize. As indicated under issue #4 the Service believes

that there is a strong relationship between water levels in the

geothermal aquifer, spring discharge and ground water pumping rates,

with short-term climatic patterns not a significant factor in the long-

term declines that have occurred. Until the trend of declining thermal

springflows is reversed, the Bruneau Hot Springsnail will remain

endangered because of threats to its habitat.

In 1995, the State of Idaho authorized the creation and supervision

of Water Management Districts (WMD) by IDWR (Idaho Code (I.C.) 42-705

et seq.). Activities to be performed include monitoring of ground water

levels at ground water diversions before and during pumping activities;

and immediate reporting to the Director any water diversions that may

have been diverted without a water right or in violation of a water

right. To date, the Bruneau/Grandview area has not been

[[Page 32990]]

designated as a WMD. The Service is aware of only one WMD to be

developed for the State of Idaho--for the Eastern Snake River Plain.

The Service recognizes that the water conservation and other

measures could be implemented to the benefit of Bruneau Hot Springsnail

habitat in this region, and finds that participation in these programs

could contribute significantly to reducing some of the short-term

threats to the Bruneau Hot Springsnail. However, only the State of

Idaho has the regulatory authority to set limits on the development of

new wells, impose conservation measures, and require meters on all

wells in the Bruneau/Grandview area (IDWR 1992). Other than the

restriction mentioned above for new agricultural use wells, no other

regulatory measures have been exercised by IDWR. It should be noted

that as of June 9, 1997, and the implementation of the Conservation

Reserve Program (CRP) and the restriction of no new agricultural use

wells, there has not been any significant improvement to water levels

in the geothermal aquifer.

In 1995, the Bruneau Valley Coalition developed a proposed

``Habitat Maintenance and Conservation Plan for the Bruneau Hot

Springsnail'' (Plan). The Plan proposed two phases of implementation.

Phase 1 had four tasks including: (1) collection and analysis of

existing data; (2) downhole geophysical testing to identify wells that

may have subsurface leakage problems; (3) development of corrective

action plans and cost estimates for repair of leaking wells; and (4)

identification of additional wells that may be impacting Bruneau Hot

Springsnail habitat. Phase 2 included six tasks: (1) implementing

corrective actions, such as casing, grouting, sealing and/or abandoning

specific wells identified in Phase 1; (2) information and education

programs targeting congressional offices, farm and ranch families and

other entities to support water conservation programs such as the

Conservation Reserve Program; (3) locate private abandoned leaking

wells previously unaccessible due to private property access

constraints; (4) investigate water transfers, including swapping ground

water for early season surface flood water; (5) develop an alternative

water supply for the Indian Bathtub spring; and (6) evaluate the

feasibility of transplantation sites for new Bruneau Hot Springsnail

colonies. On March 3, 1995, the Service met with Jim Yost, representing

the Bruneau Valley Coalition, to discuss our comments and suggestions

regarding the proposed Plan. In summary, the Service noted that the

Plan: (1) was limited to a 6-mile radius from the Indian Bathtub spring

and failed to address other critical ground water withdrawal areas; (2)

appears to be a ``more studies'' approach rather than corrective

actions; (3) does not provide information on the amount of water that

would be conserved if a well was repaired or provide an accounting

system for monitoring the success of well repairs; and (4) needed to

state a goal that reflected the removal of threats to the species or

that the aquifer would be maintained at a specific level, measured by

water levels within specific wells. Additionally, the Plan makes no

commitment on the part of any of the signatory parties to implement

specific actions. The Service has not been contacted subsequently and

is unaware whether the Bruneau Valley Coalition's Plan has been

finalized or approved by any of the affected interested parties.

During the September 1995 public comment period, the Governor of

Idaho stated that ``as soon as the bull trout conservation plan is

complete, (he) will turn the State's attention to developing a

conservation plan for the (Bruneau Hot Springsnail)'' (Phillip E. Batt,

Governor of Idaho, in litt. 1995). As of June 9, 1997, no conservation

plan for the Bruneau Hot Springsnail had been initiated or developed by

the Governor's office. On August 11, 1997, the Governor's office

invited several agencies and individuals to participate in a Bruneau

Hot Springsnail Conservation Committee. Two meetings have been

organized by the State to discuss and update the Bruneau Hot

Springsnail biological information. Actions to remove the threats to

the species have not been discussed. The Service strongly supports this

effort and will continue to participate in these efforts by the State.

Issue 7: Many respondents indicated that the Service should

consider the following actions for restoration/recovery of the species

to preclude listing of the species: transplant the Bruneau Hot

Springsnail back to Hot Creek; exchange water rights with BLM-held

water rights to benefit the Bruneau Hot Springsnail; substitute surface

water for the loss of ground water; mitigate the effects of flash

flooding in Hot Creek; develop individual Habitat Conservation Plans.

It was also noted that the ban on new wells and rehabilitation of new

wells has occurred and therefore additional protection for the Bruneau

Hot Springsnail is unnecessary.

Service Response: According to section 2(b) of the Act, ``* * * the

purposes of this Act are to provide a means whereby the ecosystems upon

which endangered species and threatened species depend may be

conserved.'' Although captive propagation and translocation can be

valid conservation tools in recovery efforts for some species, the

Service maintains that in the case of the Bruneau Hot Springsnail,

these measures would not contribute to secure, self-sustaining

populations in their natural habitat. Translocation can only occur into

native, secure habitats; therefore, the question of adequate thermal

springflows must be addressed prior to any translocation efforts. The

Service acknowledges that restoring springs flows within the historic

range (i.e., Hot Creek) of the Bruneau Hot Springsnail would contribute

to recovery of this taxon. Without the assurance of adequate

springflows in Hot Creek or at the Indian Bathtub spring, actions to

remove sediment from the Indian Bathtub would not provide for improved

habitat conditions at that site. Water rights exchange, surface water

substitution, development of Habitat Conservation Plans and other

actions that may improve habitat suitability for the Bruneau Hot

Springsnail will be addressed during during the development of a

recovery plan for this species.

The Service has acknowledged that in 1982 IDWR instituted a ban on

all new agricultural (nondomestic) wells. We are unaware however, of

any rehabilitation efforts for leaking of existing wells (see issue #4

for further discussion of well leakage). The persistent trend in

decline of the geothermal aquifer continues to be the primary concern

for the survival and recovery of the Bruneau Hot Springsnail.

Issue 8: A few comments indicated that funding has been provided

for Bruneau Hot Springsnail conservation and that an accounting of that

funding should be provided. The Bruneau Valley Coalition questioned

what the Service has done specifically to protect the Bruneau Hot

Springsnail.

Service Response: The U.S. Congress appropriated money to the

Service to fund studies starting in 1987. Information gained from the

studies was to be used to develop a cooperative conservation

(management) plan to aid in the long-term conservation and protection

of the Bruneau Hot Springsnail. To date a conservation plan has not

been finalized. The three entities involved in the studies for the

cooperative conservation planning efforts included the IDWR, USGS, and

ISU. The IDWR was to accomplish three primary tasks through the

studies: (1)

[[Page 32991]]

prepare a Geographic Information System (GIS) for the study area; (2)

prepare geological maps to define the bedrock geology and record the

location, elevation, flow and temperature of area springflows; and (3)

evaluate and analyze Federal and State laws applicable to development

of a conservation plan for the Bruneau Hot Springsnail and assess

management alternatives open to IDWR to protect the species habitats.

The Service also provided funds for the USGS to develop and implement a

three-phase ground water study of the Bruneau River valley and basin.

The study focused on the hydrology of the regional geothermal system

and surrounding hot springs, with an overall goal to determine the

cause of declining springflows affecting the Bruneau Hot Springsnail.

Finally, the Service provided funds to the Stream Ecology Center, ISU,

to study the biological, ecological, and physiological needs of the

Bruneau Hot Springsnail. The Service also entered into a short-term

conservation agreement with Owen Ranches, Inc., owners of much of the

snail's habitat in Hot Creek and the Indian Bathtub springs. Terms of

the agreement included fencing to regulate livestock use. Expiration of

this agreement coincided with the completion of the hydrologic studies

by USGS.

In 1990 through 1996, subsequent to the funding provided by the

Congressional appropriation, the Service has provided funding to USGS,

ISU, and IWRRI to continue various monitoring efforts. From September

1994 through September 1996, the Service provided funds to the USGS to

conduct the following action items on an annual basis: (1) monthly

water-level measurement for 11 wells in the Bruneau area; (2) semi-

annual water-level measurement for one well; (3) operation of

continuous water-level recorders in 6 wells; (4) monthly discharge

measurements for 8 springs; (5) annual ground water pumpage in Sugar,

Bruneau, and Little Valleys; and (6) flume construction for spring

discharge measurement (first year only). Due to Service-wide funding

shortfalls, these funds were unavailable after September 1996.

The Service also provided: funding to IWRRI to develop preliminary

information regarding well-leakage (see issue #4 for more detailed

information); funding to ISU in 1993 and 1996 to re-survey Bruneau Hot

Springsnail habitats along the Bruneau River; and additional funding to

ISU in 1994 to conduct a thermal spring invertebrate survey along the

Bruneau River.

In addition to the Congressional appropriation and Service funding,

the BLM has provided challenge cost-share funding from 1994 through

1997 to ISU to continue biological/ecological studies on the Bruneau

Hot Springsnail at three monitoring sites. The BLM also funded the

installation of additional fencing around Hot Creek drainage on the

west side of the Bruneau River and cadastral surveys (elevational

measurements) of selected springs in the Bruneau River. Maintenance of

the fencing along the west side of the Bruneau River is being provided

by the permittees in the affected allotments. An Environmental

Assessment for fencing on the east side of the Bruneau River has been

written, but is currently under protest by the Idaho Watershed Project.

Until the concerns by this group are resolved, the BLM has provided

upland watering for livestock as well as requiring permittees to

provide weekly riding in the Bruneau River canyon and removal of any

livestock that may stray into the river corridor.

Issue 9: Many respondents were concerned with the effect of the

Conservation Reserve Program (CRP) reductions and asked whether the

Service has consulted on proposed requirement and eligibility changes

in the program. It was also asserted that the Service should encourage

more participation in the CRP.

Service Response: As discussed under Factor A, ``Summary of Factors

Affecting the Species'', the loss of participation in the CRP could

have a serious effect on the continued withdrawal of water from the

geothermal aquifer. As further discussed in issues #2, 4, 5 and Factors

A and D in ``Summary of Factors Affecting the Species'' of this rule,

water withdrawals have an effect on the continuing decline of the

geothermal aquifer, and consequently the loss of thermal springs along

the Bruneau River. In spite of the enrollment of nearly 6,880 acres of

Bruneau area croplands in the CRP since 1981, water levels in the

geothermal aquifer continued to decline. The Service believes that

total well discharge has declined from a maximum of 61,526.7

dam3 (49,900 ac-ft) in 1981 to 42,785 dam3

(34,700 ac-ft) in 1991, in large part due to area farmer participation

in the CRP. The Service continues to support the CRP and the Natural

Resources Conservation Service (NRCS) in its efforts to promote

participation in the program. However, landowner participation in the

program is voluntary. If present water management practices continue,

or the CRP lands are returned to production, or when drier spring and

summer climatic conditions return, all affecting pumping rates and

duration, water levels in the aquifer will either continue to decline

or eventually stabilize at a lower level resulting in the further loss

of Bruneau Hot Springsnail habitat.

In regards to the question of whether or not NRCS has consulted

with the Service on the CRP, under section 7 of the Act, NRCS must make

the determination whether the agency action is a ``major construction

activity'' (50 CFR 402.12 (b)), and if so, the Federal agency must

prepare a biological assessment of the action for listed species that

occur in the action area (50 CFR 402.12 (j)). If the Federal agency

determines that the action will likely adversely affect any listed

species, the Federal agency must request formal consultation with the

Service (50 CFR 402.12 (k)(1)).

The CRP is administered by the Farm Services Agency (FSA) on the

local level. The process for participation in the CRP is as follows:

(1) an FSA representative completes an environmental benefits

evaluation for the proposed CRP agreement, which includes an evaluation

of the potential benefits to listed species; (2) if the proposal is

accepted, an FSA representative develops a contract with the landowner;

and (3) the FSA representative completes an environmental evaluation

checklist, including an evaluation of any potential impacts to listed

species. The determination for listed species is reviewed by NRCS for

technical assistance and, at the option of NRCS, is sent to the Service

for informal consultation. To the Service's knowledge, there has been

no request for consultation from NRCS on the new CRP.

Issue 10: A representative of the Southwestern Idaho Desert Racing

Association stated that the use of off-road vehicles is not a threat to

any sites occupied by the Bruneau Hot Springsnail. Therefore, no

restrictions on off-road vehicle use should result from listing.

Service Response: The Service agrees that off-road vehicle use may

not currently pose a threat to habitat occupied by the Bruneau Hot

Springsnail. Under section 7 of the Act, it is the responsibility of

the BLM to determine whether these activities pose a threat to the

Bruneau Hot Springsnail or its habitat (see also issue #9). The

consultation process would be completed if the Service and the BLM

agreed that there was no effect on the listed species.

Issue 11: Some respondents believed that grazing does not currently

[[Page 32992]]

adversely impact the survival of the Bruneau Hot Springsnail or its

habitat. In fact, grazing may actually improve habitat conditions by

reducing overgrown vegetation that would otherwise render habitat

unsuitable for the Bruneau Hot Springsnail.

Service Response: The Service agrees that the maintenance of

adequate fencing has served to reduce the direct impacts from livestock

grazing on this species and its habitat in the Hot Creek drainage and

along the west side of the Bruneau River. Livestock grazing on Federal

lands within or adjacent to Bruneau Hot Springsnail habitats is

authorized by the BLM and would be evaluated by the Service at the

request of, and in consultation with, the BLM. The Service does

believe, however, that the continued failure by Bruneau Hot

Springsnails to return into the upper Hot Creek drainage is not limited

by increased vegetative cover as a result of removal of livestock in

the Hot Creek drainage. As already noted in the Background section of

this notice, recruitment appears to be limited by the continued lack of

adequate springflows, preferred substrate surfaces, weak migration

abilities, and lack of an upstream colonization source.

Issue 12: One comment expressed the concern that the Service did

not provide the materials cited in the Federal Register notices of

public comment periods outside of Boise.

Service Response: The Service provided copies of all materials

cited in the public comment period Federal Register notices upon

request. The Service has opened three separate comment periods, with

the first comment period beginning on September 12, 1995 and the fourth

comment period ending on June 9, 1997, for a total of 218 days. Due to

requests from several individuals, the Service sent copies of materials

to 15 individuals or groups including, but not limited to: the Idaho

Farm Bureau Federation; Scott Campbell, representing the Bruneau Valley

Coalition; Fred Grant, representing Owyhee County; John Uriquidi; Ted

Hoffman; and Frank Sherman, representing IDWR.

Issue 13: Many respondents believe that the rights of private

property owners will be violated as a result of restrictions associated

with the listing of the Bruneau Hot Springsnail. The comments suggested

that the Service should purchase private property considered essential

to the Bruneau Hot Springsnail's survival, or should compensate

landowners for not being able to fully utilize their property (e.g.,

through the loss of water rights or grazing leases). Additionally, a

takings assessment should be prepared prior to any listing decision.

Service Response: Issuance of this rule will not constitute a

taking of private property. This rule does not make a determination

about activities that may occur on private property.

Issue 14: Some respondents indicated that the elevations of several

springs (greater than 883.9 m (2,900 ft)) are higher than the Indian

Bathtub spring elevation. They questioned the connection between these

springs, the geothermal aquifer and water loss associated with the

Indian Bathtub spring.

Service Response: All thermal springs containing Bruneau Hot

Springsnails along the Bruneau River, including the Indian Bathtub

spring, arise from a single, regional geothermal aquifer. Spring

discharges in the Bruneau Valley are related to the potentiometric

levels (the imaginary surface representing a total head of ground water

and defined by the level to which water will rise in a well) in the

geothermal aquifer. As discussed by Berenbrock (1993), Pence Hot

springs has a lower elevation (787.9 m (2,585 ft)) than the Indian

Bathtub spring (814.7 m (2,672.9 ft)). Prior to 1966, discharge from

the Indian Bathtub spring ranged from about 6,587.5 to 9,687.5 L/min

(1,700 to 2,500 gal/min). After 1966, discharge from the Indian Bathtub

spring began to decline to the point of its current flow, which

essentially ceases seasonally. However, some springs with lower

elevations (e.g., Pence Hot Spring), continued to flow at ``normal''

rates through September 1996. The reduction or loss of flow for springs

at higher elevations reflects the lower potentiometric surface within

the aquifer. Berenbrock (1993) found four cones of depression in the

potentiometric surfaces for both the sedimentary and volcanic-rock

aquifers, the largest of which occurs in the sedimentary aquifer and

reflects a long-term water-level decline due to withdrawals. As the

potentiometric surface continues to decline, springs with lower

elevations will be affected in the same manner as Indian Bathtub

spring. The continued lowering of the potentiometric surface may have

resulted in the disappearance of additional springs since 1991. (see

issue #1 and Factor A, ``Summary of Factors Affecting the Species'' for

further discussion of the loss of springs.)

The Service believes that the confusion regarding spring elevations

stems from the spring surveys conducted by the BLM (Brunner, in litt.

1994). The Service's understanding of the measurements in the BLM

document, is that all the springs measured (12 in total) were between

803.7 and 815.7 m (2636.09 and 2676.61 ft) with the Indian Bathtub

spring at an elevation of 814.7 m (2672.89 ft). The measurements that

are greater that these 12 springs were not actual springs but refer to

reference and control sites used by the BLM for establishing the

elevations of the springs (Brunner, in litt. 1994). Most of these

higher ``elevation'' sites are located at the Bruneau River canyon rim

(referred to as ``tie-in'' locations), or these sites represent a bench

mark that was established as a control point to the tie-in locations.

The elevation of the actual springs is within 1.2 m (4 ft) of Indian

Bathtub spring. These springs are downstream of the Hot Creek

confluence on the west side of the Bruneau River. Spring elevational

measurements were taken at the initial point of spring discharge.

Bruneau Hot Springsnails do not necessarily occur at that initial point

but are usually found slightly lower on the rockface. This is due to

tendency of the outflow to spread over the rockface, providing the

wetted area necessary to create suitable habitat for Bruneau Hot

Springsnail (see Background section for further details on habitat

requirements).

In summary, although recent information indicates a slight increase

in water levels at 5 of 16 wells between 1994 and 1996, the total

number of thermal springs and Bruneau Hot Springsnail occupied habitats

has declined since 1991 along the Bruneau River. The most significant

threat, ground water withdrawals, has not been addressed for the

species. Opposing comments were based primarily upon concerns that

listing of the Bruneau Hot Springsnail would affect the allocation of

water and impact agricultural development in the Bruneau Valley. Some

opposing comments questioned the adequacy of the Service's data. The

Service has continued to gather information regarding the status of the

species since publication of the listing rule in 1993. As discussed in

the ``Summary of Factors Affecting the Species'' section, the Service

concludes that all of the remaining populations of the Bruneau Hot

Springsnail continue to be at risk.

Issue 15: Commenters suggested that a National Environmental Policy

Act (NEPA) analysis should be prepared prior to listing.

Service Response: For the reasons cited in the NEPA section of this

rule, the Service has determined that rules issued pursuant to section

4(a) of the Act do not require the preparation of an

[[Page 32993]]

Environmental Assessment or Environmental Impact Statement.

Summary of Factors Affecting the Species

After a thorough review and consideration of all information

available, the Service has determined that the Bruneau Hot Springsnail

should continue to be classified as an endangered species. Procedures

found at section 4 of the Act (16 U.S.C. 1531 et seq.) and regulations

(50 CFR part 424) promulgated to implement the listing provisions of

the Act were followed. Under the Act, species may be determined to be

endangered or threatened due to one or more of the five factors

described in section 4(a)(1). This determination is based on the

``Summary of Factors Affecting the Species'' and on comments received

on the rule. These factors and their application to the Bruneau Hot

Springsnail (Pyrgulopsis bruneauensis) are as follows:

A. The Present or Threatened Destruction, Modification, or Curtailment

of its Habitat or Range

Agricultural-related ground water withdrawals threaten the

continued existence of the Bruneau Hot Springsnail.

Ground water withdrawal and pumping threaten the Bruneau Hot

Springsnail through a reduction or loss of thermal spring habitats

resulting from the decline of the geothermal aquifer that underlies

Bruneau, Little, and Sugar Valleys in north-central Owyhee County,

Idaho. Within the past 25 years, discharge from many of the thermal

springs along Hot Creek and the Bruneau River has decreased or has been

lost, thus further restricting the Bruneau Hot Springsnail habitats

(Young et al. 1979; Berenbrock 1993; Mladenka and Minshall 1996).

The Indian Bathtub area and Hot Creek represent the type locality

of the Bruneau Hot Springsnail. By 1982, Taylor (1982) found that the

Bruneau Hot Springsnail population in the Hot Creek/Indian Bathtub site

had been significantly reduced by the reduction in spring discharge.

Taylor (1982) noted that the core of the population occurred on

vertical rock cliffs (rockface sites) protected from flash flood

events. Varricchione and Minshall (1997) also found that ``The rockface

sites are probably more suitable for Bruneau Hot Springsnail success .

. .'' (page 50). Spring discharge in 1964 was approximately 9,300 L/min

(2,400 gal/min), had dropped to between 503.8 to 627.8 L/min (130 to

162 gal/min) (Young et al. 1979), and by the summer of 1990 discharge

was zero during the summer and early fall water withdrawal season

(Berenbrock 1993). Taylor (1982) speculated that this reduction in

rock-face seep flows would leave the species vulnerable to the

occasional flash-flood events known to occur in the Hot Creek drainage.

Today, water from the Indian Bathtub spring is below the ground surface

and reemerges about 300 m (984.3 ft) below the bathtub area

(Varricchione and Minshall 1997). Visible spring discharge at the

Indian Bathtub continues to be seasonal and low, ranging from 0 to 11

liters per second (0 to .39 cubic feet per second) and is intermittent

in most years (Varricchione and Minshall 1997; Cowing, in litt. 1996).

This loss of discharge translates into a 10 m (35 ft) decline in water

levels in the aquifer feeding the Indian Bathtub spring (Berenbrock

1993).

Beginning in the late 1890's, when ground water development for

domestic and agricultural purposes began in the area of the geothermal

aquifer, an estimated 339,075 dam \3\ (275,000 ac-ft) of thermal water

discharged from Indian Bathtub spring (Berenbrock 1993). Between 1982

and 1991, only 1,726 dam \3\ (1,400 ac-ft) discharged from the spring

(Berenbrock 1993). This decline in discharge from the Indian Bathtub

spring was noted beginning in the mid-1960's and coincided with the

accelerated increase in ground water withdrawal associated with a rapid

increase in the amount of lands irrigated with ground water throughout

the area. From the late 1890's through 1991, nearly 1,726,200 dam \3\

(1,400,000 ac-ft) of water was discharged from flowing and pumped wells

completed in the geothermal system (Berenbrock 1993).

According to Berenbrock (1993) the two most apparent effects of

pumping stress are declines in hydraulic head and declines in spring

discharge. Discharge fluctuations correspond with the pumping season;

lower flows in the late spring to early fall and high flows during late

fall to spring. Changes in discharge from thermal springs corresponds

with changes in hydraulic head, which fluctuate seasonally and are

substantially less during late summer than in the spring (Berenbrock

1993).

It should be noted that ground water withdrawals have generally

declined over the past 15 to 20 years, primarily due to cropland

retired from production through participation in the CRP (Berenbrock

1993). In the last 2 years, the time periods of ground water use during

the irrigation seasons have been shorter and occurred later in the

spring due to increased precipitation in Bruneau area (Cowing, in litt.

1996). However, water levels in the geothermal aquifer have continued

to decline, with a possible slight increase in 5 of 16 wells at the

completion of the 1995-1996 water withdrawal season (Cowing, in litt.

1996), again, due primarily to increased precipitation in 1995-1996 in

the Bruneau area and thus less need for ground water withdrawals. The

Service is concerned that the number of withdrawals may again increase

in the next few years as croplands will again enter production when the

current 10-year CRP expires. As of June 9, 1997, there were 24 active

CRPs (acreage total is 6,880) in the Bruneau area, 13 of which are due

to expire in October 1997 (acreage total is 5,500), 8 will expire in

October 1998 (acreage total is approximately 1,000 acres) and the

remaining CRPs will expire in October 1999 (Ron Abbott, Farm Service

Agency (FSA), in litt. 1997). There are approximately 15,822 acres in

CRP for all of Owyhee County. (See Factor D for further discussion of

the CRP.) If present water management practices continue, or if the CRP

lands are returned to production, or when drier spring and summer

climatic conditions return, all of which affect pumping rates and

duration, water levels in the aquifer will either continue to decline

or will eventually stabilize at a lower level, resulting in the further

loss of Bruneau Hot Springsnail habitat.

While the decline/loss in springflows at Indian Bathtub spring and

several other springs has been documented, springflow data has not been

collected in all the remaining 116 springs containing Bruneau Hot

Springsnails. Mladenka (1992) believes that prior to the recent decline

in water levels in the aquifer and resultant fragmentation of remaining

populations, all of the springs and seeps supporting Bruneau Hot

Springsnails were connected to allow the natural dispersal and transfer

of individuals. The studies conducted by Mladenka (1992) and Mladenka

and Minshall (1993, 1996) indicate a general decline in the total

number of thermal springs along the Bruneau River, the number of

springs occupied by Bruneau Hot Springsnails, and a general decline in

densities of Bruneau Hot Springsnails (see Background section for

further discussion). In 1993, Mladenka and Minshall found dead Bruneau

Hot Springsnails at one previously occupied spring site where flows had

recently diminished and nine spring sites showed noticeable reductions

in discharge (Mladenka and Minshall 1993). The majority of Bruneau Hot

Springsnail occupied thermal springs

[[Page 32994]]

are located upstream of the confluence of Hot Creek to the Bruneau

River (Mladenka and Minshall 1996). Since 1991, the total number of

thermal springs in the referenced section of the Bruneau River has

decreased by approximately 5 percent, the number of springs occupied by

Bruneau Hot Springsnails has decreased by 10 percent, and the total

area occupied by Bruneau Hot Springsnails has decreased by 13 percent

(Mladenka and Minshall 1996). Total site area (including all springs

and seeps, occupied and unoccupied by Bruneau Hot Springsnails)

increased by 4.3 percent from 1991 to 1996 (Mladenka and Minshall

1996). Most of this increase occurred due to lower flows resulting in

more surface exposure of a single thermal spring outflow area below

Buckaroo Dam, which is downstream of the majority of occupied springs

(Mladenka and Minshall 1996). Further analysis of the total spring

surface area shows a 32 percent decrease in upper (above the confluence

with Hot Creek) occupied springs versus a 41 percent increase in lower

occupied springs (Mladenka and Minshall 1996). This corresponds to a 20

percent decrease in the number of occupied sites upstream of the

confluence of Hot Creek to the Bruneau River, a 17 percent decrease in

the number of occupied sites at the confluence, and a 45 percent

increase in the number of occupied sites downstream of the confluence

(see Background section for further information). At this time there is

no information available indicating how much lower water levels can

continue to decline before all thermal springs along the Bruneau River

are lost. As potentiometric surfaces in the geothermal aquifer continue

to decline, additional spring discharges will be reduced or lost,

resulting in the continued loss of Bruneau Hot Springsnail habitat.

In the original 1993 listing it was indicated that impacts had

occurred as a result of cattle grazing in Bruneau Hot Springsnail

habitats, especially along Hot Creek. These impacts included trampled

instream substrates and habitats causing direct Bruneau Hot Springsnail

mortality and displacement. Cattle also browsed and removed riparian

vegetation, allowing temperatures to reach levels affecting

reproduction or to ultimately be lethal to the Bruneau Hot Springsnail.

Additionally, livestock grazing in the adjacent watershed, combined

with ongoing drought conditions, contributed to an increase in

sedimentation in Hot Creek, which eliminated Bruneau Hot Springsnail

seep/spring habitats for almost 150 m (492 ft) in the Indian Bathtub/

Hot Creek drainage.

The BLM has controlled livestock grazing by installing fencing on

the north end of Hot Creek drainage and the west side of the Bruneau

River. The BLM also plans to install additional fencing along the east

side of the Bruneau River. Both fencing projects, if properly

maintained, will protect Bruneau Hot Springsnail habitat from the

effects of livestock.

The original 1993 listing stated that recreational access also

impacts habitats of the Bruneau Hot Springsnail along the Bruneau

River. For example, small dams are sometimes constructed to form

thermal pools and improve conditions for bathing. Construction of these

pools could impact Bruneau Hot Springsnails through habitat

modification as rock substrates are moved, flow is altered and

sediments are trapped. These pools can also alter and possibly destroy

the madicolous habitats preferred by the Bruneau Hot Springsnail as

pool water levels are raised. Most of the springs along the Bruneau

River are inaccessible to bathers due to an abundance of poison ivy

(Rhus radicans). One or two pools downstream of the confluence of Hot

Creek are used by recreational bathers but Bruneau Hot Springsnails

have not been verified in those locations. Therefore, recreational use

of the thermal springs and outflows is not considered a significant

threat.

In summary, the cumulative effects of water withdrawal continue to

threaten the increasingly fragmented populations of the Bruneau Hot

Springsnail and their thermal habitats.

B. Overutilization for Commercial, Recreational, Scientific, or

Educational Purposes

There are no commercial uses for this species. In other listing

actions, certain mollusc species have become vulnerable to illegal

collection for scientific purposes. Because the distribution of the

Bruneau Hot Springsnail is restricted and generally well known,

collection could become a threat to Bruneau Hot Springsnails.

C. Disease or Predation

There are no known diseases that affect Bruneau Hot Springsnails.

Juvenile Bruneau Hot Springsnails (less than 0.7 mm) are vulnerable to

a variety of predators (Mladenka 1992). Damselflies (Zygoptera) and

dragonflies (Anisoptera) were observed feeding upon Bruneau Hot

Springsnails in the wild. The presence of a large wild population of

guppies in Hot Creek and several of the other small thermal springs

downstream along the west bank of the Bruneau River is a potential

threat to the Bruneau Hot Springsnail. Mladenka (1992) observed guppies

feeding upon the species in the laboratory. In addition to guppies, a

species of Tilapia has ascended into and reproduced in Hot Creek

(Bowler 1992). The presence of this new potential ``exotic'' predator

may constitute a threat to the Bruneau Hot Springsnail by restricting

repopulation of the species into Hot Creek (Varricchione and Minshall

1997) and at other thermal spring sites that may be available to the

Bruneau Hot Springsnail and the exotic fish species. Both of these

exotic fish species can migrate into the Bruneau River corridor, both

upstream and downstream of Hot Creek, and to other spring outflows when

temperatures in the Bruneau River are suitable (usually during the

summer months). Movement of these exotic fish species into other

thermal springs occupied by the Bruneau Hot Springsnail might affect

their continued survival within individual spring sites.

It should be noted that madicolous habitats support neither of

these two exotic fishes or dragonflies, but do harbor numerous

damselflies. During his study, Mladenka (1992) observed no birds

preying on the Bruneau Hot Springsnails.

In summary, the Service considers the presence of predatory exotic

fish species in Hot Creek and the Bruneau River drainage a possible

threat to the Bruneau Hot Springsnail, which should be studied further.

D. The Inadequacy of Existing Regulatory Mechanisms

At least three State agencies could potentially assist in the

protection of the Bruneau Hot Springsnail. The IDPR has authority under

I. C. Section 18-3913, 1967, to protect only plants, with animals not

given special protection on Idaho lands. The IDFG, under I. C. Section

36-103, is mandated to preserve, protect, perpetuate, and manage all

wildlife. However, these mandates do not extend protection to

invertebrate species.

The IDWR regulates water development in the Bruneau area. It is the

policy of IDWR to regulate and conserve ground water resources from

depletion or ``mining''. In Baker v. Ore-Ida Foods, Inc 95 Idaho 575,

513 P.2d 627, 635 (1973), the Idaho Supreme Court held that ``Idaho's

Ground Water Act clearly prohibits the withdrawal of ground water

beyond the average rate of recharge.'' However, any conservation

measures imposed by IDWR to manage ground water ``mining'' are only for

the

[[Page 32995]]

purpose of fulfilling senior water rights and not for the protection of

fish and wildlife. At present, there is no specific allocation of

either surface or ground water in the Bruneau area for the protection

and conservation of fish and wildlife. In 1982, the IDWR established

the Bruneau-Grandview GWMA pursuant to provisions of I. C. Section 42-

233a ``* * * to identify the area as approaching the conditions of a

critical ground water area'' (IDWR 1992). This GWMA designation has

allowed the IDWR to continue to receive and hold without action

applications for water permits until it can be demonstrated that the

proposed withdrawal will not adversely impact other water rights in the

GWMA. Due to the continued decline in water levels in the geothermal

aquifer, no applications for agriculture withdrawal within the GWMA

have been approved since 1982. Without recovery of water levels, IDWR

does not anticipate modification of the GWMA designation any time soon.

In any event, GWMA designations are intended only to maintain

sufficient ground water to fulfill existing water rights and supply the

needs of irrigation, and not for the protection and conservation of

fish and wildlife.

The Bruneau area is also located entirely within the area of an

ongoing water rights adjudication (Snake River Basin Adjudication). A

Director's Report, due to the court in 1994, was to clarify existing

water rights and water uses and permit IDWR to eliminate water rights

that are of record but are no longer utilized. The IDWR also believes

the adjudication process will need to be completed prior to the

development and implementation of ground water conservation measures on

behalf of the Bruneau Hot Springsnail that may affect existing water

rights and uses since ``without completing this adjudication process

there is no effective way to determine the existence or validity of

water rights to serve as the basis for delivery'' (IDWR 1992). As of

June 9, 1997, the Director's report, filed with the court, has not

included agricultural reports from the Bruneau area.

In 1995, the State of Idaho authorized the creation and supervision

of Water Management Districts (WMD) by IDWR (Idaho Code (I.C.) 42-705

et. seq.). Among the activities to be performed by a qualified district

hydrographer in a WMD is--the monitoring of ground water levels at

ground water diversions before the pumping period begins and during the

pumping period; and immediate reporting to the Director of the

diversion of any water appearing to be diverted without a water right

or in violation of a water right. To date, the Bruneau/Grandview area

has not been designated as a WMD. The Service is aware of only one WMD

that is to be developed for the State of Idaho--for the Eastern Snake

River Plain.

Under the Idaho Ground Water Act, IDWR also regulates the

construction and maintenance of geothermal (I. C. Section 42-238(4))

and artesian (I. C. Sections 42-1601 and 42-1603) wells so that they

operate to conserve ground water resources and prevent unnecessary flow

and waste. The IDWR in 1990 identified several artesian wells in the

Bruneau area ``* * * leaking water at land surface or potentially

wasting water in the subsurface due to inappropriate well construction

techniques'' (IDWR 1992). To date no action has been taken to have

these leaking wells rehabilitated so that the aquifer pressures can be

preserved or increased. In 1995, the Service had provided funding to

IWRRI to research the problem of well leakage in the Bruneau Valley. As

of June, 1997, only one landowner had volunteered to participate in the

research. The results of the research by IWRRI have not yet been

submitted to the Service.

In summary, the IDWR has authority to control ground water and can

limit the development of new wells in a critical ground water area,

impose water conservation measures, and also require meters on existing

wells. To date, no action has been taken by IDWR to regulate

implementation of water conservation actions or metering and repair of

wells. IDWR has stated that

``* * * the Director has no authority under State law to shut down

prior vested water rights in order to protect an endangered species''

(IDWR 1992). Therefore, measures taken by IDWR have been inadequate for

the protection and recovery of habitats for the Bruneau Hot

Springsnail.

The BLM manages the public lands containing Bruneau Hot

Springsnails and their habitats along Hot Creek and the Bruneau River.

The BLM issues permits for livestock grazing on these lands and grants

authorizations that could lead to the drilling of new wells or

increased ground water use on BLM lands. In the past, the BLM has shown

an interest in conserving the species and has solicited input from the

Service regarding impacts that may result from any proposed activities.

As discussed in Factor A, the BLM has implemented fencing to protect

Bruneau Hot Springsnail habitats from grazing impacts.

The CRP is authorized under the Food Security Act of 1985, as

amended, to implement a voluntary program that offers annual rental

payments, incentive payments for certain activities, and cost-share

assistance to establish approved cover on eligible cropland (U.S.

Department of Agriculture (USDA) 1997). This program encourages farmers

to plant long-term resource-conserving covers to improve soil, water,

and wildlife resources. The duration of the contracts are between 10

and 15 years (USDA 1997). As discussed in Factor A, all of the current

lands in CRP will expire by 1999. It is unlikely that all those

eligible for the new CRP agreements will participate due to a dramatic

drop in the rental rates (from about $50 per acre to about $20 per

acre) currently offered through the CRP (Abbott, in litt. 1997). Area

landowners have indicated that this drop in rental fees will not

provide the necessary incentive to continue participating with the CRP.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

Sedimentation of Bruneau Hot Springsnail habitats is a threat to

this species. Summer floods and mudflows during 1991 and 1992 delivered

significant amounts of sand, silt and gravel to upper Hot Creek, and as

of July 1992, completely filling the Indian Bathtub with at least 1 m

(3 ft) of sediment (Robinson, et al., 1992). Following sediment

delivery from a flash flood in October 1992, additional springflows

have been completely covered over and Bruneau Hot Springsnail habitat

eliminated from approximately 150 m (492 ft) in upper Hot Creek below

the Indian Bathtub. While flash floods probably occurred historically,

the decreased flushing effects of declining springflows have resulted

in the filling in of Bruneau Hot Springsnail habitats at the Indian

Bathtub and upper Hot Creek. Sediment deposited by periodic flash

floods cannot be flushed by the remaining weak and declining

springflows. Measures which could protect Bruneau Hot Springsnail

spring/seep habitats in the Indian Bathtub and Hot Creek from the

effects of flash flooding have not been implemented. These measures

include the construction of small retention dams in the Hot Creek

watershed to trap runoff sediment while maintaining thermal seep

habitats. Therefore, sedimentation and flooding continue to threaten

Bruneau Hot Springsnail habitat.

Determination

The Service has carefully assessed the best scientific and

commercial information available regarding the past, present, and

future threats faced by the Bruneau Hot Springsnail. Based on this

[[Page 32996]]

evaluation, the preferred action is to retain the Bruneau Hot

Springsnail as an endangered species. The species persists in only a

few isolated thermal springs and seeps in Hot Creek and along an 8 km

(5 mi) reach of the Bruneau River characterized by temperatures ranging

from 15.7 to 35 deg. C (60.3 to 95 deg.). The free-flowing thermal

spring and seep environments required by the Bruneau Hot Springsnail

have been impacted by and are vulnerable to continued reduction from

agricultural-related ground water withdrawal/pumping. The species and

its habitat are also vulnerable to habitat modification from the

effects of flash floods. The remaining complex of thermally related

springs and their immediate outflows are not protected from the threats

previously discussed. Existing regulations do not provide adequate

protection to prevent further direct or indirect habitat losses. The

Bruneau Hot Springsnail is in danger of extinction throughout all or a

significant portion of its range, and therefore, fits the definition of

endangered as defined in the Act.

National Environmental Policy Act

The Fish and Wildlife Service has determined that an Environmental

Assessment, as defined under the authority of the National

Environmental Policy Act of 1969, need not be prepared in connection

with regulations adopted pursuant to section 4(a) of the Endangered

Species Act of 1973, as amended. A notice outlining the Service's

reasons for this determination was published in the Federal Register on

October 25, 1983 (48 FR 49244).

Author

The primary author of this rule is Jeri Wood, Snake River Basin

Office, U.S. Fish and Wildlife Service, 1387 S. Vinnell Way, Room 386,

Boise, Idaho (208/378-5243).

Authority

The authority for this action is the Endangered Species Act of 1973

(16 U.S.C. 1531 et seq.).

Dated: June 5, 1998.

Jamie Rappaport Clark,

Director, Fish and Wildlife Service.

[FR Doc. 98-16099 Filed 6-16-98; 8:45 am]

BILLING CODE 4310-55-P