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51.1248 (Com Creek Irrigation Dist.)

FINAL Ef\JVJ RON MENTAL

.fJA \.,1v"·~ ..~"'SMEJT\ ..J r V IT "

CORN CREEK IRRIGATION PROJECT FINAL ENVIRONMENTAL ASSESSMENT

CORN CREEK IRRIGATION PROJECT

Prepared by CH2M HILL Denver, Colorado

for Corn Creek Irrigation District

November 1985 CONTENTS

I Purpose and Need for Action I-I

Introduction I-I Purpose and Need 1-3

II Alternatives II-I

Water Diversion Alternatives II-I Storage Reservoir Alternatives 1I-3 Project Alternatives 1I-6

III Affected Environment III-I

Physical Components III-I Biological Components III-7 Socioeconomic Components III-IS

IV Environmental Consequences IV-l

Teeters Reservoir with Diversion Weir IV-I Teeters Reservoir with Infiltration Gallery IV-29 No-Action Alternative IV-30 v Consultation and Coordination V-I

Literature Cited

Appendix A. Bird and Mammal Species Lists Appendix B. Hydrology Data Appendix C. Agency Comments on the Draft Environmental Assessment

DE/30R/133

ii TABLES

1 Laramie River Flows Upstream of the Confluence with the North Platte River, During 3 Years Selected to Represent Average, Wet, and Dry Years in the Laramie River Basin 1II-3

2 Laramie River Discharge (cfs) and Water Quality Data Upstream of the Confluence with the North Platte River 1II-4

3 Glendo Reservoir Storage Data 1I1-5 4 Guernsey Reservoir Storage Data 1II-6

5 Monthly North Platte River Flows at Whalen Diversion Dam During 3 Years Selected to Represent Average, Wet, and Dry Years in the North Platte River Basin 1II-8

6 North Platte River Water Quality Between Glendo Reservoir and the Wyoming-Nebraska State Line 1II-9 7 North Platte River Discharges Between Glendo Reservoir and the Wyoming-Nebraska State Line III-I0

8 Summary of Water Releases from Storage Reservoirs, Water Withdrawals by CCID, and Resultant Flow Changes Downstream of the CCID IV-5 9 Laramie River and North Platte River Flows During the 37-Year Period 1941 through 1977 IV-6 10 North Platte River Flows with and without the Corn Creek.Project at Selected Sites (with 11,250 ac-ft Replacement Water at Fort Laramie) IV-7

11 North Platte River Flows with and without the Corn Creek Project at Selected Sites (with 11,250 ac-ft Replacement Water at Fort Laramie) IV-9 12 Monthly North Platte River Flows and Expected Depletions at Fort Laramie Due to the Corn Creek Project during Average, Wet, and Dry Years (1,000 ac-ft) IV-13

iii TABLES (continued)

13 Monthly North Platte River Flows and Expected Depletions at the Wyoming-Nebraska State Line due to the Corn Creek Project during Average, Wet, and Dry Years (1,000 ac-ft) IV-14

DE/30R/133

iv FIGURES

1 Location Map I-2

2 Diversion Dam Alternate II-2

3 Infiltration Gallery Alternate II-4

4 Corn Creek Irrigation Project-­ Teeters Alternate 1I-5

5 Corn Creek Irrigation Project-­ Glomill Alternate II-7

DE/30R/I33

v Purpose and Need for Action I. PURPOSE AND NEED FOR ACTION

A. INTRODUCTION

The Corn Creek Irrigation District (CCID) is situated in Goshen County, Wyoming, approximately 20 miles southwest of the City of Torrington (Figure 1). The District extends south of the confluence of the Laramie and North Platte Rivers and includes a corridor through the physiographic area known as Harmony Heights, with the remainder in the Goshen Hole region. The general area drains to the southeast and ranges in elevation from 5400 feet at the upper end to 4200 feet at the southeast boundary.

The Corn Creek Reservoir Association was formed in 1966 and was later reorganized as the Corn Creek Irrigation District, according to the laws of the State of Wyoming. The District has the power of eminent domain and the authority to levy such taxes as necessary to repay any loans and operating costs.

The District boundaries encompass approximately 70,000 acres. The land use within the District is approximately 40 percent dry cropland and 60 percent rangeland. The District has defined over 15,000 acres of privately owned land within their boundaries that would receive irrigation water from the proposed project.

On July 24, 1974, the Corn Creek Reservoir Association and Basin Electric Power Cooperative on behalf of the Missouri Basin Power Project (MBPP) entered into a contract which guarantees the delivery of 22,500 acre-feet (ac-ft) annually to Corn Creek.

The contract is for a firm annual supply of water, and there are no allowances for a reduction in supply during drought periods. Although the water is generally assumed to be sup­ plied from storage in Grayrocks Reservoir, the contract only requires that MBPP allow sufficient water to pass through Grayrocks and down the Laramie River to make the primary water rights for 22,500 ac-ft available to the Corn Creek Irrigation District (15,000 ac-ft between April 1 and Sep­ tember 30 and 7,500 ac-ft between October 1 and March 31).

In addition to the firm supply from Grayrocks Reservoir, there are two other proposed water supplies for the project. The second supply is the supplemental water right for 10,100 ac-ft/year from the Bureau of Reclamation's (USBR) Glendo Reservoir. The Glendo Reservoir supply is available in all years except during an extended drought lasting over 3 years (CH2M HILL, 1983). This supply will have to be con­ tracted from the USBR, and negotiations are currently

I-I 'Tq GUERNSEY

WYOMING '\

PROJECT LOCATION-+-

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TO C fEYENNE

CH2M FIGURE 1 IIHllL LOCATION MAP underway. The third supply is the possibility of a direct­ flow diversion from the Laramie River. However, use of this right would be subordinate to all senior rights and is not expected to produce a viable firm yield on an annual basis. A filing has been submitted to the State Engineer for this right and would be of use only under extreme hydraulic con­ ditions.

The proposed project consists of a surface water diversion system, a pump station on District-owned land at the conflu­ ence of the Laramie and North Platte Rivers capable of pump­ ing 75 cubic feet per second (cfs), a reservoir to store winter diversions and to provide pressure head, a main pipe­ line to deliver water to the project area, and distribution laterals to provide water to each land parcel.

CH2M HILL was retained by the Wyoming Water Development Com­ mission (WWDC) in November 1982 to perform an investigation which would develop and evaluate the economic feasibility of a conceptual plan that would allow for the delivery of water to approximately 15,000 acres in the CCID. Within the scope of these services, an evaluation of the irrigation potential of the soils was conducted and preliminary design criteria were developed. Various alternative configurations and de­ signs were evaluated and it was determined that the project is feasible from an engineering standpoint (CH2M HILL, 1983). When both direct and indirect benefits are considered, the project also is economically feasible with a benefit/cost ratio of 1.84. A 50-year evaluation period was selected to calculate the benefit/cost ratio, and costs were discounted using the 7-7/8 federal discount rate.

B. PURPOSE AND NEED

The area economy is primarily agricultural. For example, 85 percent of the business trade in the Torrington area is based on agriculture. Mean annual precipitation for the region is about 14 inches, but ranges from less than 8 to more than 22 inches. Spring rains are usually sufficient to start crop growth, but normally the precipitation during August and September is very low. Without irrigation water some dry land wheat cropping is practical, but most of the area is limited to use as rangeland. The growth of the area's economy, therefore, is limited as ~ong as agriculture is primarily dryland crops and rangeland, with the resultant fluctuating crop yields.

Existing irrigation developments in neighboring areas have demonstrated that favorable crop production is possible when a full and assured water supply is available. Goshen County currently has about 150,000 acres of land under irrigation, and the CCID development would add another 10 percent to that total. Development of irrigation service to new lands

I-3 in the area by CCID would not only help stabilize and improve agricultural production, but it would enhance the tax base and the economic growth potential of the area. Conversion of rangeland to Class 2 irrigated land increases the tax valuation of the property significantly.

The January 1953 stipulation to the original (1945) North Platte Decree issued by the u.s. Supreme Court mandated that 15,000 ac-ft of Glendo Reservoir water be allocated annually for irrigation in southeastern Wyoming, specifically within the area between Guernsey Reservoir and the Wyoming-Nebraska state line. At the present time, the USBR has less than 5,000 ac-ft of that allotment under contract. The CCID rep­ resents one of the few feasible irrigation developments in southeastern Wyoming that could use the Glendo allocation and has essentially completed contract negotiations with the USBR for that water. If CCID lands are not developed, the Glendo allocation would continue to be unused for some unknown time period, and the 22,500 ac-ft of water committed to the project from Grayrocks Reservoir may never be used to enhance agriculture in Wyoming.

Interest in irrigation in the area dates back to the latter part of the 19th century. That interest still prevails, as evidenced by the action by local farmers, businessmen, and community organizations. Development of CCID lands would improve the area's agricultural base, and provide an oppor­ tunity to put land under irrigation using available surface water.

DE/23R/I08

1-4 Alternatives II. ALTERNATIVES

The project would consist of a water diversion facility, a river pumping facility, a storage reservoir, and a distribu­ tion system. Since the District has diversion rights to flows year-round, the diversion facility and pump station must have the capabilities to divert and pump a wide range of flows. A storage reservoir is needed to store winter diversions and off-peak summer diversions and to supplement river withdrawals during peak irrigating operations. The distribution system must have the capability of delivering water to the center pivot irrigation system from either the river pumping station or the storage reservoir, or both si­ multaneously. It also must have the capacity to supply enough water to irrigate approximately 15,000 acres.

For this Environmental Assessment (EA), three different water diversion structures and two difterent storage reservoir locations were considered. Only one river pumping facility was proposed because the basic configuration of this facility is fixed by the maximum and minimum flows it will be required to handle, and by the requirement to lift the water 480 feet over the Harmony Heights ridge. A closed pipe distribution system is proposed because of several distinct advantages over an open canal system.

A. WATER DIVERSION ALTERNATIVES

Considering a minimum diversion rate of 21 cfs and a maximum diversion rate of 75 cfs or greater, and the location of the District's property at the confluence of the Laramie and North Platte rivers, three possible diversion schemes were considered.

1. SURFACE WATER DIVERSION

An analysis of available data indicated that a low-water diversion dam (weir) could be installed on the North Platte River just below its confluence with the Laramie River (Fig­ ure 2). This location would permit diversion of water from the North Platte River (i.e., releases from Glendo Reser- voir) and from the Laramie River (i.e., releases from Grayrocks Reservoir or direct flow water rights). The proposed dam could be a concrete ogee section approximately 175 feet in length and 3 feet high. A diversion canal on the south abutment would extend from the abutment to the pump station. Other construction would consist of approximately 100 feet of overflow embankment at the north abutment, and a small levee along the Laramie River to protect the pump station and the canal.

II-1 OVERFLOW EMBANKMENT WITH RIPRAP FACE CREST ELEV 4214 8

FiI VER RETAINING WALL

PROTECTING LEVEE 5:1 SIDE SLOPES, CREST ELEV 4222± \ HIGHLY VEGETATED 10 FT ROADWAY ON TOP __~

-:;:::;- :;;.-- 4 X 4 GATE ~ -;::::::­ ------::;:::: ,;;;;.-- ~-::::::--

~ 10' WIDE X 5' DEEP CHANNEL TO HIGH GROUND

""---_- PUMPSTATION

PLAN (NOT TO SCALE) 48-INCH DISCHARGE PIPE TO DISTRIBUTION SYSTEM

10 FT

sJ ~ ____M_A_S_S_C_O~N~C_R_ET_E ______

I..---PILES 5 FT ON CENTER DRIVEN TO BEDROCK

aGEE SECTION (NOT TO SCALE)

FIGURE 2 DIVERSION DAM ALTERNA TE CJ-i2M II HILL

II-2 2. INFILTRATION GALLERY

A second alternative would be to install an infiltration gallery in the Laramie River. The Laramie River at its con­ fluence with the North Platte basically assumes the hydraulic properties of the North Platte River during the summer month high flows. This allows an infiltration gallery installed in the Laramie River to remove both the Grayrocks and Glendo releases.

An infiltration gallery would consist of approximately 1,125 feet of 36-inch-diameter screen installed parallel to the Laramie River and the District's northern property bound­ ary (Figure 3). The screen would be installed in the river bed at a depth of 5 feet. The screen could be installed in two sections with a manifold pipe connecting the screens. A 48-inch pipe would then extend from the manifold to the sump of the pump station. The pump station would be designed such that a suction head could be impressed across the screens to deliver peak capacities when adequate flows are avail­ able.

3. ALLUVIAL GROUNDWATER WELLS

A third alternative would be to install alluvial wells on the District's 21 acres·which front both the Laramie and North Platte rivers at their confluence. The District's property consists of approximately 2,400 lineal feet of Laramie River frontage with alluvium extending along this interface in an east-west direction. Along this interface, the alluvium thickness varies from 0 to 50 feet.

Utilizing a maximum pumping rate of 75 cfs [33,650 gallons per minute (gpm)] and an estimated well spacing of 400 feet between each well, a total of six wells could be installed within the District's property boundaries. However, this would require that each well pump 5,600 gpm at peak pumping times, and with the available information, this does not appear to be feasible. This alternative therefore is con­ sidered infeasible from an engineering viewpoint and was not considered further in this report.

B. STORAGE RESERVOIR ALTERNATIVES

Two sites were identified as potential sites for a dam and reservoir, Teeters Ranch and the existing Glomill Reservoir.

1. TEETERS RESERVOIR SITE

The proposed Teeters Reservoir would be located on Cherry Creek, as shown in Figure 4. The reservoir would have a capacity of 15,000 ac-ft, and a dam height of approximately

11-3 ~I

LARAMIE RIVER

±1125 FEET

36-INCH INFILTRATION SCREEN

48-INCH INTAKE PIPE

,....---.~... -----.-... - ..-.---

PUMP STATION

~--48-INCH DISCHARGE PIPE TO DISTRIBUTION SYSTEM

PLAN (NOT TO SCALE)

PUMP STATION

VtWATER LEVEL

FEET

48-INCH DISCHARGE PIPE TO DISTRIBUTION SYSTEM 36-INCH INFILTRATION SCREEN ELEVATION (NOT TO SCALE)

FIGURE 3 INFILTRATION GALLERY ALTERNATE Q-t2M II HILL

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CH2M =:IIILL 43 feet. This capacity includes the storage required for normal operation, plus additional storage and a spillway for the design storm runoff. The dam at Teeters Reservoir would be an intermediate dam with a low hazard potential classi­ fication. According to recognized dam safety criteria, the required spillway design flood will be between a 100-year flood and one-half Probable Maximum Flood. Final configura­ tions will be detailed during the design phase. The site appears to be technically feasible, although additional soil borings would be needed during predesign to address concerns for the abutment and embankment construction, aggregate ma­ terials, and spillway location. All lands on this site are privately owned and within the CCID boundaries. Approximately 800 acres would be flooded. 2. GLOMILL RESERVOIR

Glomill Reservoir, an existing reservoir on Box Elder Creek, is approximately 3 miles south of the Irrigation District's boundaries (Figure 5). To meet project requirements, the reservoir would need to be enlarged. The reservoir would require a capacity of 14,000 ac-ft and a dam height of approx­ imately 45 feet, assuming a spillway is constructed to pass the design storm runoff. The spillway design flood requ~re­ ments would be similar to those for the Teeters Reservoir.

The Glomill site appears technically feasible as a dam loca­ tion. However, it was not considered further as an alterna­ tive for this report for the following reasons:

o It is located outside of the Irrigation District's boundaries and hence would be more difficult to implement politically.

o It is an existing recreation (fishing) lake which would be disturbed during construction and perhaps during the operation of the project. o Its construction costs are estimated to be approx­ imately 21 percent greater than the Teeters alter­ native.

o It apparently offers no technical, economic or environmental advantage over the Teeters Reservoir alternative.

C. PROJECT ALTERNATIVES For this report, therefore, three project alternatives were considered: Teeters Reservoir with the diversion weir, Teeters Reservoir with an infiltration gallery, and the No­ Action Alternative.

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CH2M =:'-ULL 1. TEETERS RESERVOIR WITH DIVERSION WEIR

The preferred alternative for this project would consist of a low water diversion weir on the North Platte River below the confluence of the Platte and Laramie rivers, a 75-cfs capacity river pumping station, a storage reservoir at the Teeters Reservoir site with a 120-cfs reservoir pump station, and a closed pipe distribution system serving approximately 15,000 irrigated acres.

The diversion weir on the North Plate River was described previously in subsection II.A.1 (Figure 2), and the Teeters Reservoir was described in subsection II.B.1 (Figure 3). The proposed distribution system would be a closed pipe system to transport water from the river pumping station to the irrigated lands, with an interconnection to the storage reser­ voir. Depending upon the operation mode, river water could be transported directly to on-farm systems or the storage reservoir, or both. Also, under peak operating conditions, up to 120 cfs of reservoir water could be pumped into the distribution system to supplement the maximum river flows of 75 cfs.

A closed pipe system is proposed because of its distinct advantages over an open canal system. These are:

o The head developed when dropping into Goshen Hole can be utilized by the sprinkler systems, thus saving energy that would be required to pressurize an open system.

o Seepage, evaporation, and operational conveyance losses are virtually eliminated.

o Operation and maintenance costs are considerably reduced.

o Wintertime operation is possible.

o The system can be operated on a "demand" basis eliminating the need for ditch riders.

The proposed pipe system would pass through dryland wheat, short-grass prairie, and fallow fields (Figure 4). The sys­ tem would require approxim9tely 78 miles of pipe, and the tentative pipe routes are entirely on private land.

There are approximately 15,000 acres of land within the CCIn boundaries that are proposed for irrigation (Figure 4). This proposed acreage reflects the elimination of over 2,000 acres originally proposed but subsequently excluded because of severe limitations of slopes, rock outcrops, or unsuitable soils. Preliminary estimates indicate that approximately

11-8 15,200 acres can be irrigated with a water supply of 32,600 ac-ft.

Lands that would be put into production consist of three general vegetation types: cultivated dryland wheat, fallow lands (lands once under production but allowed to return to pasture vegetation), and short-grass prairie. Most of the fallow and short-grass prairie lands are currently grazed by domestic livestock and pronghorn antelope. Most of the pro­ posed production lands are privately owned except for 800 acres of state land which would also be put under irrigation. The cropping pattern after project completion is estimated to be small grains (10 Percent), dry beans (16 Percent) , sugar beets (12 Percent), corn (21 Percent), and alfalfa (41 Percent) [Soil Conservation Service (SCS), 1979].

A river pumping plant with a total rating of approximately 6,200 horsepower (hp) would be required to pump the maximum diversion at a lift of 480 feet. Seventy-five cfs is the flow rate required to be pumped 24 hours per day from May through September. From October through March, an average rate of 21 cfs would be required as per primary water rights agreements for water trom Grayrocks Reservoir. In April, 42 cfs would be required.

Under the proposed plan, the water would be lifted approxi­ mately 480 feet up to the top of the ridge near Harmony Heights and then it would flow by gravity pressure to all parts of the irrigation system. The water pumped from the river during nonirrigation periods would be stored in the project reservoir. During peak use by the irrigation system, the 75-cfs flow from the river must be supplemented by up to 120 cfs pumped from the reservoir into the pipe network. The water pumped from the reservoir must be pressurized to approximately 235 feet of head to be compatible with the mainline pressure developed after the drop over the ridge above Harmony Heights.

The reservoir pump station, with a peak capacity of 120 cfs at 235 feet of head, would require approximately 5,600 horse­ power. The operating flows may vary from 0 to 120 cfs, and the operating heads may range from 60 to 235 feet. Therefore, it is quite likely that the reservoir pump station would include a series of variable-speed units.

The system can be designed so that the reservoir pumps are flow- and pressure-activated and would only operate when needed to augment the flow from the river pumping station (during June, July, and August). During periods of low­ irrigation demand, all flows pumped from the river in excess of that required for the irrigation system would be stored in the reservoir.

II-9 Teeters Reservoir is sized essentially to be filled and emp­ tied each year with no carryover capacity. However, the Teeters site has potential for extra capacity if this is deemed desirable in final design. The reservoir will be near capacity in June before the start of the peak-irrigation demands and at its lowest level in October. The estimated cost of this alternative (January 1983) is about $35,100,000.

2. TEETERS RESERVOIR WITH INFILTRATION GALLERY

The second alternative would be similar to the preferred alternative except that instead of the low water diversion dam, an infiltration gallery would be used. The estimated cost of the total system (January 1983) would be approximately $35,400,000.

3. NO ACTION

The third possible alternative would be the no-action alter­ native.

DE/29R/2l

11-10 Affected Environment III. AFFECTED ENVIRONMENT

A. PHYSICAL COMPONENTS

1. TOPOGRAPHY, SOILS, AND CLI~~TE

The Corn Creek Irrigation District lies in the southern half of Goshen County, Wyoming; in the High Plains Section of the Great Plains province (Figure 1). Most of the CCID lands are within the Goshen Hole Lowland, a great local widening of the North Platte Valley. Goshen Hole is an undulating to rolling plain that has gentle to moderately steep foot slopes along the base of the Goshen Hole rim. The relief is broken by several buttes and outliers of the Western Nebraska and Eastern Wyoming Uplands (SCS, 1971). Most of the Goshen Hole area is drained by Cherry Creek. Immediately north and northeast of the District's lands a high sandy benchland area known as Harmony Heights separates the Goshen Hole area from the North Platte and Laramie River valleys. The conflu­ ence of these two rivers is approximately 1.5 miles north of the northern boundary of the District.

The valley along the North Platte River consists of stream bottoms bordered by stream terraces and foot slopes. The stream bottoms are 4 to 12 feet above the river channel and range in width from a few hundred feet to 2 miles. In many places the terraces are indistinct, especially south of the river. The climate in the project area is semiarid. Precipitation at Torrington averages 14.8 inches annually with 11.1 inches falling during April through September. Temperature extremes range from 30°F to 40°F below zero to over 100°F, and the area is subject to wide and sometimes abrupt changes in weather. The January average is 24.6°F, and the July average is 72.6°F. The average frost-free period is 136 days, and the growing season is about 154 days (Hurlbut, Kertsich, and McCullogh, 1975).

Overall air quality of the area is excellent, typical of the rural environment. During periods of high winds and dry conditions, dust blowing from agricultural fields may be a local problem. Predominant winds are from the west. The average windspeed is 13 miles per hour (mph), and the strong­ est winds usually occur between November and May.

The Goshen Hole soils are typically gently sloping, medium­ textured, well drained aeolian and alluvial soils developed from area sandstone, siltstone, and shale. The area is drained by two small creek systems, Cherry Creek to the north­ east and Box Elder Creek to the South. In the finer textured soil areas, there are many flat-sloped, depressional areas

111-1 that have significant accumulation of alkali salts in the subsoils.

2. WATER RESOURCES

Water supplies for the Corn Creek Irrigation District would include Grayrocks Reservoir via the Laramie River, Glendo Reservoir via the North Platte River, and perhaps direct flows from the Laramie River on rare occasions. As discussed previously, the primary water right comes from Grayrocks Reservoir and the secondary water right is from Glendo Res­ ervoir.

Grayrocks Reservoir, on the Laramie River about 8 miles above CCID, was constructed to supply cooling water for the MBPP (or Laramie River Generating Station). The reservoir covers about 3,500 surface acres and has a capacity of 104,100 ac-ft. Additional information on the dam and reservoir can be found in the Final EIS and the Supplemental Ers for the MBPP (Rural Electrification Administration [REA], 1976 and 1980).

Flows in the Laramie River, near its confluence with the North Platte River and just above the proposed diversion location, have averaged 80,500 ac-ft per year over the 37-year period between 1941 and 1977 (Appendix B and Water and Power Resources Services, 1980). Laramie River flows usually peak in the spring or early summer (April-June) and are fairly low during the remainder of the year (Appendix B). Monthiy flows from 3 years that are representative of average, wet, and dry years during the 1941-1977 period are shown in Table 1. Flows, and associated water quality data for 3 recent years (1980-1982), are presented in Table 2.

Glendo and Guernsey Reservoirs on the North Platte River, about 30 and 15 miles upriver of the North Platte and Laramie rivers confluence respectively, are operated by the u.S. Bureau of Reclamation for irrigation storage and hydroelec­ tric power. Water from these reservoirs is used for power production and irrigation in eastern Wyoming and western Nebraska, as authorized by Congressional Act. Because of irrigation demands, both of these reservoirs usually reach minimum storage levels in September or October, remain fair­ ly low through the winter months, and reach maximum storage during the spring snowmelt just prior to the irrigation sea­ son. The annual storage cycles for the 1980, 1981, and 1982 water years are shown in Table 3 (Glendo) and Table 4 (Guernsey). The U.S. Supreme Court Decree has allocated portions of Glendo Reservoir waters specifically for irriga­ tion in both Wyoming and Nebraska, and has mandated that these waters be released only during the irrigation season (May through September). The use of stored water by each state and the impacts on flow regimes in the North Platte River were addressed in the planning studies and the Court

III-2 Table 1 LARAMIE RIVER FLO~vS UPSTREAM OF THE CONFLUENCE WITH THE NORTH PLATTE RIVER, DURING 3 YEARS SELECTED TO REPRESENT "AVERAGE, WET, AND DRY YEARS IN THE LARAMIE RIVER BASIN (Flow in 1,000 ac-ft units)

Wet Average b Dry b Flow Year a Flow Year Flow Year Months 1943 1947 1953

Jan 1.5 0.7 1.1 Feb O.S 0.5 O.S Mar 10.1 3.1 0.9 Apr 24.S 3.1 4.2 May 16.6 14.4 4.1 Jun 11.6 4S.9 2.4 Jul 6.9 27.1 2.6 Aug 4.1 10.9 4.6 Sep 2.4 6.9 1.S Oct 0.9 4.9 2.S Nov 0.6 O.S 3.2 Dec 0.4 2.5 0.6

TOTAL SO.7 123.S 29.1

a A year during the 1941-1977 period that is close to the average annual flow during the 37-year period. bA year in the upper (wet) or lower (dry) quartile, but not the wettest or dryest years that represent unusual extremes.

Source: Point Flow Study, North Platte River, 1941-1977. Water and Power Resources Service. July 19S0.

DE/23R/134

III-3 Table 2 LARAMIE RIVER DISCHARGE (cfs)a AND WATER QUALITY DATA UPSTREAM OF THE CONFLUENCE WITH THE NORTH PLATTE RIVER (USGS Station 06670500)

1982 1981 1980 Water Year Water Year Water Year

DISCHARGES

Mean 32.1 26.1 186 Max 128 61 1,190 Min 12 2 5.8 Acre-feet 23,240 18,930 135,100

WATER QUALITY (Range)

Specific Conductance (lImhoS) 730-830 740-840 440-880 pH 7.9-8.2 7.7-8.3 8.0-8.3 Temperature (OC) 0.5-18 1.0-18 0.5-18 Turbidity 2-5 (NTU) 2-8 (NTU) 3-25 (JTU) Dissolved Oxygen (mg/L) 7.4-11.8 8.6-13.0 7.8-12.4 Hardness (mg/L as CaC0 ) 290-310 290-330 99-340 3 Dissolved Solids (mg/L) 500-540 495-550 130-605 Suspended Solids (mg/L) 6-78 10-54 15-182

Period of Record -(POR) April 1915 to Present (for Discharge Data) Extreme for POR Max Discharge 6,260 cfs Date 5-10-73 Min Discharge o cfs (all flows diverted to Gering­ Ft. Laramie Canal) Date Several days in 1926, 1927, and 4-14-38 a cfs = cubic feet per second: flows include natural flow water plus storage water released for irrigation or other purposes.

Source: Water Resources Data for Wyoming, Water Years 1980, 1981 and 1982. U. S. Geological Survey.

DE28R/071

III-4 Table 3 GLENDO RESERVOIR STORAGE DATA (Thousands of Acre-Feet) [Period of Record = October 1957-September 1982]

Water Year 1980 1981· 1982 Max Min Max Min Max Min

October 168 77.4 191 89.6 174 82.2 November 236 173 258 194 233 176 December 301 237 324 260 282 234 January 357 303 386 326 331 283 February 441 359 437 388 383 333 March 508 443 473 438 434 384 April 528 497 484 473 444 435 May 540 516 542 481 473 404 June 514 442 544 416 514 476 July 436 286 409 241 498 336 August 278 112 230 108 329 120 September 109 67.6 105 70.5 115 69.3

Reservoir Data Drainage Area 15,545 square miles Spillway Crest Height 4,653 feet Maximum Capacity 789,400 ac-ft Dead Storage 11,030 ac-ft Maximum Storage for Period of Record 758,800 ac-ft (5-28-73) Minimum Storage for Period of Record 15,140 ac-ft (9-28-66) Dam Completed October 1957

Source: Water Resources Data for Wyoming, Water Years 1980, 1981, and 1982. U. S. Geological Survey.

DE28R/072

111-5 Table 4 GUERNSEY RESERVOIR STORAGE DATA (Thousands of Acre-Feet) [Period of Record = January 1928 to Current]

Water Year 1980 1981 1982 Max Min Max Min Max Min

October 14.8 1.0 15.2 4.9 13.9 4.3 November 4.0 2.1 4.2 2.4 7.8 6.1 December 5.2 4.1 5.8 4.2 8.8 7.8 January 6.5 5.2 7.5 5.8 9.5 8.8 February 9.4 6.5 8.9 7.5 10.2 9.5 March 13.9 9.5 10.5 9.0 10.9 10.3 April 35.1 15.0 32.6 10.5 29.5 10.9 May 37.2 33.6 41.3 32.2 36.1 28.9 June 37.0 32.3 40.5 33.7 36.4 31.2 July 35.7 1.6 35.6 1.8 34.9 0.6 August 31.7 3.7 32.1 21.5 37.0 0.2 September 33.0 16.3 31.6 15.4 35.0 1.7

Reservoir Data Drainage Area 16,224 square miles Spillway Crest Height 4,420 feet Maximum Capacity 45,600 ac-ft Dead Storage Negligible Maximum Storage for Period of Record 73,240 ac-ft (10-17-29) Mintmum Storage for Period of Record 30 ac-ft (10-5&6-58, and 10-18 to 11-3-69) Dam Completed July 1927

Source: Water Resources Data for Wyoming, Water Years 1980, 1981, and 1982. U. S. Geological Survey.

DE28Rj073

III-6 Decree. Cumulative hydrologic effects of present and future developments were previously addressed by the USBR in their North Platte River hydrology studies.

Flows in the North Platte River between Glendo Reservoir and the Wyoming-Nebraska state line are controlled by the reser­ voir operations and vary from early summer highs of several thousand ac-ft per month to late fall and winter minimums of 1,000 to 3,000 ac-ft per month when the dam releases are curtailed (Table 5 and Appendix B). Flows in the North Platte River during late fall and winter are due primarily to seepage through the dams, inflow from small tributaries, and local precipitation. Inflow from the Laramie River contributes about 18 percent of the flow in the North Platte River at its confluence with the Laramie River (Appendix B). Water quality in the North Platte is good, but summer temperatures are fairly high due to low flows and irrigation return flows. Water quality data, and the associated flows for 3 recent years (1980-1982), are presented in Tables 6 and 7.

B. BIOLOGICAL COMPONENTS

1 • VEGETATION

Lands within the proposed irrigation development support five general vegetation types: short-grass prairie, fallow lands, dryland crops, riparian vegetation, and shrub stands. The dominant vegetation type, based on acreage covered, is fallow lands. These lands were once under agricultural pro­ duction but have been returned to pasture vegetation. Fallow lands account for about 45 percent of the acreage within the District boundaries. Native short-grass prairie covers about 28 percent of the District's lands. Typical grasses in this vegetation type include blue grama, buffalograss, western wheatgrass, needle-and-thread grass, and switchgrass. Sage­ brush is also common in the area. Most of the fallow and shortgrass prairie lands are currently grazed by domestic livestock and pronghorn antelope.

About 25 percent of the area is dryland cropland, primarily winter wheat. Other small grains raised on dryland include spring wheat, barley, and oats.

The fourth vegetation type within the District is riparian vegetation, primarily along Cherry Creek and smaller creek bottoms. The riparian zone is maintained by subsurface waters. The wet meadow areas contain grasses, rushes, and sedges, and small cottonwood trees and willows are scattered along creek drainages.

111-7 Table 5 a MONTHLY NORTH PLATTE RIVER FLOWS AT WHALEN DIVERSION DAM DURING 3 YEARS SELECTED TO REPRESENT AVERAGE, WET, AND DRY YEARS IN THE NORTH PLATTE RIVER BASIN (Flow in 1,000 ac-ft units)

Wet Dry Average b c c Flow Year Flow Year Flow Year Months 1975 1974 1953

Jan 0.1 0.1 0.2 Feb 0.1 3.0 0.1 Mar 0.0 238.9 0.7 Apr 13.6 225.0 1.0 May 31.4 82.4 21.4 Jun 57.3 150.6 39.9 Jul 122.2 105.0 72.6 Aug 83.8 67.9 44.4 Sep 27.9 17.1 30.2 Oct 7.6 7.6 1.9 Nov 0.5 0.4 1.0 Dec 0.1 0.1 0.4

TOTAL 344.6 898.1 213.8

~Whalen Dam is about 10.5 miles above the confluence of the North Platte and Laramie Rivers. bA year during the 1941-1977 period that is close to the average annual flow at the confluence of the North Platte and Laramie Rivers during the 37-year period. c A year in the upper (wet) or lower (dry) quartile, but not the wettest or dryest years that represent unusual extremes.

Source: Point Flow Study, North Platte River, 1941-1977. Water and Power Resources Service, July 1980.

DE/23R/135

III-8 Table 6 NORTH PLATTE RIVER WATER QUALITya BETWEEN GLENDO RESERVOIR AND THE WYOMING-NEBRASKA STATE LINE

Below Below At WY-NE Glendo Guernsey State Line Water Year/Parameters (06652800)b (06656000) (06674500)

1982 Water Year Specific Conductance (l.unhos) 710-800 636-731 750-1,000 pH 7.7-8.1 8.0-8.5 7.6-8.2 Temperature °C 0-21 0.5-15 5-23 Turbidity (NTU) 1-4 NA 2-270 Dissolved Oxygen (mg/L) 10.5-13.2 NA 7.4-11.7 Hardness (mg/L as CaCO ) 230-330 220-280 250-300 Dissolved Solids (mg/LY 410-570 390-470 460-660 Suspended Solids (mg/L) NA NA 18-716

1981 Water Year Specific Conductance 620-780 630-755 600-1,060 pH 7.9-8.9 7.8-8.7 8.0-8.5 Temperature 2-21 1-20 2-25 Turbidity (NTU) 1-6 1-2.6 2-25 Dissolved Oxygen 7.6-16.1 11.6-14.4 7.8-12.6 Hardness 220-270 210-290 240-300 Dissolved Solids 380-480 269-478 470-681 Suspended Solids NA NA 10-125

1980 Water Year Specific Conductance 560-820 575-650 645-1000 pH 7.5-8.9 8.3-8.5 8.0-8.2 Temperature 3-23.5 2-22 0.5-22.5 Turbidity (JTU) 1-15 NA 5-40 Dissolved Oxygen 7.9-14.8 NA 8.3-12.6 Hardness 210-280 200-310 220-310 Dissolved Solids 340-532 350-530 380-685 Suspended Solids NA NA 71-225 a b Range of values from data collected 3 to 12 times per year. USGS Station Number NA = None available.

Source: Water Resources Data for Wyoming, Water Years 1980, 1981, and 1982. U. S. Geological Survey.

DE28R/075

III-9 Table 7 NORTH PLATTE RIVER DISCHARGES (cfs)a BETWEEN GLENDO RESERVOIR AND THE WYOMING-NEBRASKA STATE LINE

Below Below At WY-NB Water Glendo Guernsey State Line Year (06652800)b (06656000) (06674500)

1982 Mean 1,265 1,300 471 Max 7,180 5,620 1,920 Min 1.3 0.60 23 Acre-Feet (thousands) 916.0 940.8 341.3

1981 Mean 1,338 1,345 477 Max 7,440 5,400 2,110 Min 0.78 1.8 14 Acre-Feet (thousands) 968.6 973.9 345.6

1980 Mean 1,814 1,856 955 Max 7,300 5,750 3,370 Min 0.68 2.8 226 Acre-Feet (thousands) 1,317 1,348 693.4

Period of Record (POR) Oct 1957 June 1900 April 1929 to Present to Present to Present Extremes for POR Max Discharge 9,700 30,000 17,900 Date 6-1-73 6-2-08 6-2-29

Min Discharge 0.41 0 13 c Date 10-17-77 2-28-27 5-12-61 a cfs = cubic feet per second: flows include natural flow water plus storage water breleased for irrigation, flood control, and hydropower. USGS Station Number. cAnd several days in November and December, 1951.

Source: Water Resources Data for Wyoming, Water Years 1980, 1981, and 1982. U. S. Geological Survey.

DE28R/074

111-10 Mountain mahogany-bitterbrush stands are located on Harmony Heights and along the Goshen Hole Rim. These small tree­ and shrub-covered areas provide habitat for mule deer and some upland game birds.

There are no threatened or endangered plant species listed within the project area.

2. WILDLIFE

Three big-game animals are found within the CCID boundaries; mule deer, white-tailed deer, and pronghorn antelope. Mule deer frequent the fallow and short-grass prairie areas, espe­ cially during the spring, and are present in the mountain mahogany and bitterbrush stands along Harmony Heights and the Goshen Hole Rim throughout the year. The Wyoming Game and Fish Department (1984) stated that no mule deer critical ranges exist within the CCID project area. The mule deer population within the Goshen Hole Mule Deer Data Analysis Unit (D.A.U.), which includes the project area, was estimated at 2,640 deer after the 1982 hunting season. That popula­ tion was below the state's management objective.

White-tailed deer are found primarily in the riparian areas along the Laramie and North Platte rivers and Cherry Creek. No critical ranges for this species have been identified within the project area (Wyoming Game and Fish Department, 1984). The 1982 postseason population estimate by the state indicated that the wh~te-tailed deer population in the south­ east Wyoming whitetailed deer D.A.U. was around 3,800 and increasing.

The native short-grass prairie and fallow lands in the area support many pronghorn antelope. Although the prairie and fallow-land rangelands are the principal habitat for antelope, they do graze on cultivated wheat fields to some extent. No critical antelope ranges have been documented with the project area (Wyoming Game and Fish Department, 1984), and the ante­ lope population in the area is slightly above the state manage­ ment objective.

Several small game animals and fur-bearers occur in the pro­ ject area, including rabbits, squirrel, mink, weasel, badger, and a few bobcat (Appendix A, Table A-I). Three species of rabbits occupy native habitats throughout the area while muskrats, beaver, and mink inhabit riparian areas along the rivers and creeks. Bobcats are found primarily in the rocky hill habitats along Harmony Heights and the Goshen Hole Rim. Numerous non-game mammals such as shrews, ground squirrels, mice, rats, raccoons, porcupines, and prairie dogs occur throughout the area (Appendix A, Table A-I) . There are several black-tailed prairie dog colonies adjacent to proposed project lands.

III-II No specific game bird breeding habitat areas have been docu­ mented in the Corn Creek area by the Wyoming Game and Fish Department (1984), but ring-necked pheasants, sharp-tailed grouse, gray partridge, and mourning doves are :ound in the area. The grouse prefei short-grass prairie and mountain mahogany stands while the pheasants utilize agriculture lands throughout the District.

Numerous non-game bird species are common in the area, and several waterfowl can be found along the Laramie and North Platte rivers (Appendix A, Table A-2). Wyoming Game and Fish Department personnel observed 45 nongame bird species on project lands during 1983, and the area may be used by some two dozen species of waterfowl and about 150 species of nongame birds. Waterfowl are frequently observed in the spring on temporary ponds in the area that result from snow m~lt and/or spring rains.

Threatened or endangered wildlife that could potentially be in the project area include the bald eagle, peregrine falcon, and black-footed ferret. No peregrine falcons have been observed in the project area by field biologists, and this raptor would only be expected as an infrequent visitor to the area.

Bald eagles are winter migrants through the project area, and can be observed roosting and foraging along the Laramie and Platte rivers. The eagles prey on fish -and ducks found in open water areas during the winter. Although bald eagles are never numerous, two or three eagles have been observed simultaneously near the confluence of the Laramie and Platte Rivers on a few occasions.

Black-footed ferrets could be in the project area because their preferred habitat, black-tailed prairie dog colonies, are found adjacent to project lands that would be irrigated. However, no black-footed ferrets have ever been reported in the southeastern portion of Wyoming. This endangered species was considered nearly extinct, but ferrets have been observed recently in several areas in Wyoming. The areas in Wyoming nearest to the project area where black-footed ferrets have been reported are the Medicine Bow area and the upper Laramie River basin near Laramie. These areas are 75 to 100 miles west and southwest of the CCID lands.

3. FISHERIES

Glendo Reservoir and The North Platte River

Glendo Reservoir supports one of Wyoming's better walleye and yellow perch fisheries (Wyoming Game and Fish Department, 1983). These two species, together with channel catfish,

111-12 account for an angler effort of about 73,500 days/year. Glendo Reservoir is also an important source of walleye eggs and fry for stocking in waters such as Grayrocks, Keyhole, and Bighorn Reservoirs. About half the walleye fry stocked by the state since 1981 have come from Glendo Reservoir (Wyoming Game and Fish Department, 1983).

Several factors currently limit fish production in Glendo Reservoir, including severe water level fluctuations (water is normally stored from October through June and released during July-September) and a lower than normal reservoir storage over the past 5 years. Authorized allocations at Glendo Reservoir include:

Capacity of Spillway Crest Elevation 789,400 ac-ft Conservation Capacity 485,527 ac-ft Flood Control Capacity 217,889 ac-ft Inactive Capacity (Minimum Power Requirement) 64,780 ac-ft

The reservoir storage is reduced at elevations near the top of the Conservation Capacity level to maintain more efficient movement of North Platte River storage water through the reservoir. These water releases from Glendo Reservoir during the summer may result in downstream losses of young walleye and yellow perch.

The North Platte River between Glendo and Guernsey Reservoirs has been identified as a Class 2 stream by the State of Wyoming. This classification indicates "very good trout waters of statewide importance" (Wyoming Game and Fish Depart­ ment, 1983). This reach of the North Platte supports moderate numbers and standing crops of both brown trout and rainbow trout, but it is managed primarily as a brown trout fishery. Both rainbow and brown trout in the area commonly reach tro­ phy size, and average lengths are nearly 18 inches for both species.

In 1979, trout densities in the North Platte River below Glendo Reservoir were estimated at 41 rainbows and 20 browns per river mile. Densities of some rough fish were consider­ ably higher: 2,334 carp and 5,212 white sucker per mile. Other species common in the North Platte River include wall­ eye, yellow perch, longnose sucker, black bullhead, stonecat, gizzard shad, and river carpsucker.

The North Platte River between Glendo and Guernsey Reser­ voirs has been described as ~one of the most ecologically productive stream reaches in the state when normal flows are being released from Glendo Reservoir (Wyoming Game and Fish Department, 1983). However, this fishery is impacted during the nonirrigation season by flows ranging from only 2-5 cfs

111-13 just below Glendo Reservoir to about 30-40 cfs just above Guernsey Reservoir.

Most of the land adjacent to the river between Glendo and Guernsey is privately owned, and this restricted access also impacts the sport fishery value of the river.

No threatened or endangered fish species have been reported to occur in Glendo Reservoir or in the North Platte River in Wyoming below Glendo.

Grayrocks Reservoir and the Laramie River

Grayrocks Reservoir on the Laramie River covers about 3,500 surface acres, and the state is beginning to develop the south shore for recreation. The lake does not stratify, and summer water temperatures may reach the upper 70's. During the first year the reservoir was opened for fishing (1981) trout were still common and fishing pressures was relatively high (about 6,000 cars during a 140-day summer period). Fishing pressure declined in 1982-83 as the trout populations declined and the Wyoming Game and Fish Department began manag­ ing the reservoir as a warm water fishery. Planted stocks of walleye are now in very good shape and an estimated harvest of nearly 7,000 game fish was realized during the summer of 1984 (May through mid-September). Principal forage species are yellow perch and gizzard shad (Wyoming Game and Fish Department, 1985). Grayrocks Reservoir also contains large­ mouth and smallmouth .bass, black and white crappie, channel catfish, and some planted tiger muskies.

The Wyoming Game and Fish Department plans to develop the Laramie River below Grayrocks Reservoir as a bass fishery. Currently there are some trout, primarily rainbows, just below the reservoir where water released from the lake keeps summer temperatures down. However, summer water tempera- tures are best suited for warm-water fish and the river cur­ rently contains channel catfish, walleye, and stonecat. The state plans to stock smallmouth bass and develop a bass/catfish fishery.

No threatened or endangered fish species have been reported to occur in Grayrocks Reservoir or in the Laramie River below Grayrocks Reservoir.

Glomill Reservoir

Glomill Reservoir, also known as Miller Reservoir, is located a few miles south of the District's southern boundary. The reservoir supports one of the better warm-water sport fish­ eries in Goshen 'County. It is particularly important because this area of the state has few warm-water lakes. Glomill Reservoir has been stocked by the state several times between

III-14 1976 and 1983 and is managed today primarily as a largemouth bass fishery.

Glomill Reservoir supports large numbers of largemouth bass and black crappie. Yellow perch and channel catfish are . present but less abundant. Sport fishing pressure on Glomill Reservoir for these four species has been estimated to be about 265 fishermen days per year. (Wyoming Game and Fish Department, 1983). Other species present in Glomill Reservoir include black bullhead, carp, white sucker, and fathead minnow (Stone, 1983). No threatened or endangered fish species, or critical habitat, have been reported for Glomill Reservoir.

C. SOCIOECONOMIC COMPONENTS

1. POPULATION AND EMPLOYMENT

The 1979 population of Goshen County was 13,595 (Wyoming Division of Research and Statistics, 1979). This represents about 3 percent of the state's population. Although the Goshen County population is expected to increase by 14 percent between 1979 and 1990, it will be one of the slower growing counties in the state. The state's population is expected to increase by 45 percent ?uring that same time period. Only 39 percent of the people in Goshen County were living in urban areas in 1970, but this is expected to in­ crease to 53 percent by 1990. The per capita income in Goshen County was $5,097 in 1979, the lowest in the state; and the county is expected to retain that status through 1990. The 1979 statewide per capita income was $7,525 (Wyoming Division of Research and Statistics, 1979). Seventy-two percent of the workers in Goshen County in 1979 were employed in either agriculture (23.8 percent), govern­ ment (20.2 percent), trade (18.7 percent), or the service industry (9.4 percent). The largest city and principal market and trading area in Goshen County is Torrington, about 15 miles east of the CCID. Several towns are located east and southeast of CCID, including Veteran, Yoder, and Huntley.

2. LAND USE

Most of the land in southern Goshen County (greater than 95 percent) is used for farming and ranching (SCS, 1971). Cattle ranching began in the mid-1800's and has continued to be the most important livestock enterprise in the area. About 65 percent of the agricultural land in the county is rangeland.. The first irrigation canal system in the area, the North Platte Canal, was finished in 1883. Today, an extensive canal system supplied primarily from reservoirs on the North Platte River ensures sufficient distribution of irrigation water to much of the area. However, only about 10 percent of the land is irrigated cropland while dry

III-IS cropland covers about 20 percent of the area. Principal dryland crops are small grains, primarily winter wheat. Principal irrigated crops are corn, alfalfa, sugar beets, beans, and potatoes.

3. RECREATION AND AREA HISTORY

The area has a rich history, and historical sites represent an important recreational resource in the region. The first settlement in Wyoming, Fort Williams, was established in 1834 on the Laramie River near its junction with the North Platte River. The U.S. Government acquired the fort 15 years later and renamed it Fort Laramie. Today the area is a 563-acre National Historic Site run by the National Park Service. Between 1974 and 1978, there were 105,000 to 116,000 visitors per year to this historic site (Wyoming Recreation Commission, 1980). About 75 percent of the visi­ tors came during the summer months (June-August). The Fort Laramie Historic Site is located along the north side of the Laramie River extending west from the confluence of the Laramie and North Platte rivers.

Two State Historic Sites are located several miles north of Fort Laramie, the Oregon Trail Ruts Site and the Register Cliff Site. Both are small recreational areas of a few acres but historically important. Register Cliff is in Platte County.

Other than the historic sites, developed recreational areas in the near vicinity of the CCID are limited. State parks are located at Glendo and Guernsey Reservoirs on the North Platte upriver of Fort Laramie , but these areas are 15 or more miles from the CCID project area. According to the Wyoming Recreation Commission (1980 and 1981), there are only limited recreation facilities in Goshen County, and there are, or will be in the near future, serious shortages of campsites, picnic areas, and municipal parks in southeastern Wyoming.

DE28R/070

III-16 Environmental Consequences IV. ENVIRONMENTAL CONSEQUENCES

A. TEETERS RESERVOIR WITH DIVERSION WEIR

1. PHYSICAL COMPONENTS

Topography and Geology

Topography within the project area would be altered primar­ ily at the Teeters Reservoir site and less so at the North Platte diversion weir. The placement of the project pipe­ line (buried) and powerline would follow natural contours and would not change the area's topography.

The valley floor of the Cherry Creek drainage at the Teeters Reservoir site is relatively flat with steeper contours to the north and south. The dam would be placed across this valley floor and abut against the steeper slopes (Figure 4). The reservoir would approach a square configuration and cover approximately 800 acres. The dam would be about 43 feet high and one mile long, to provide storage capacity for normal operations plus the design storm runoff. The reser­ voir would replace the valley floor with a flat water surface extending from the current ridge north of Cherry Creek across to the promontory of land south of the creek (Figure 4).

Materials suitable for construction of the earthen embankment appear to be available near the reservoir site. Aggregate needed for dam filters, internal drainage, and rip-rap does not·appear to be available on the reservoir site. These materials would probably come from the Guernsey-Torrington area.

The low concrete diversion weir across the North Platte River would be 3 feet high and would form a flat water surface approximately 175 feet wide (Figure 2). In addition to the weir, a levee would extend upriver along the south shore of the North Platte River at an elevation 12 feet above the weir crest height. The levee face would be revegetated to blend with the natural ground cover. On the north shore in line with the dam, the shore profile would be modified slightly to provide a riprap overflow embankment to prevent severe erosion during high water periods.

Preliminary analysis indicates that there have been no re­ corded earthquakes producing significant ground-surface accel­ erations in the project area. However, seismic consid­ erations will be considered in the diversion dam and reservoir design.

IV-l Air Quality

Activities associated with the construction of the dam and placing the pipeline and powerline will generate dust and emissions from the engines of the equipment. None of the activities will have any lasting effects on air quality after construction is completed, and air quality would return to normal within several weeks. Construction of the Teeters Reservoir dam will produce the main construction impact with dust and emissions because large earth moving equipment will be used and construction would probably extend through the construction season. However, the area is sparsely populated. Construction of the pipeline and parallel powerline will require smaller equipment, and the constantly advancing activity will prevent the concentration of particulates over a single area. 'Construction of the pump stations and diversion dam will be structural construction, and this type of construction does not generate much dust.

Soils

The wind erosion hazard is severe in the entire area, as strongly evidenced by the return of many of the previously cultivated lands to dry pasture during the 1930's dust-bowl era. In addition, on the very sandy soils such as the Valentine and Dwyer series, there are numerous blowout areas that in places are 10- to IS-feet deep and cover areas of 10 to 30 acres (SCS, 1971). Under irrigation and cultiva­ tion, existing wind and water erosion control practices would be continued and additional controls such as establishing wind breaks, leaving corn stubble through the winter, and minimizing tillage farming would be implemented. None of the lands proposed for irrigation have slopes exceeding 4 to S percent, and irrigation with sprinklers will minimize sur­ face water runoff. Therefore, development of the ceID proj­ ect is not expected to increase erosion problems, and may reduce soil loss due to wind and water erosion.

In many of the depressional and flat drainageway areas, there are presently soils that are strongly saline-alkali either in the subsoil or the entire soil profile. With the limited rainfall in the area, soil profile salt leaching has been minimal. Under sprinkler irrigation, a leaching faction would be required to maintain and reduce salinity within the soil profile. On the strongly alkali soils, reclamation and drainage would need to be implemented in order to sustain productivity.

There presently are some areas within the irrigation District where drainage problems exist. Therefore, under irrigation, it is expected that more area drainage measures would be required. Also, water application rates would be carefully controlled. The local groundwater is at a depth of 200 to

IV-2 400 feet, and the surface geology consists of thick strata of slowly permeable sandstone and siltstone. Under these conditions, drainage by deep percolation is expected to be minimal. In fields where there are closed depressions or complex slopes, localized drainage restrictions are expec­ ted. On-farm drainage would be required to eliminate areas of extreme ponding, but areas where intermittent spring ponds develop would be left as is so ponds may form for springtime waterfowl use.

The lower reaches of Cherry Creek and Bo~ Elder Creek are broad valleys of alkali or alkali-saline soils with no de­ fined drainage channel. When the lands on either side of these valleys are irrigated, water application rates would be carefully controlled or surface drainage systems would be developed to route excess water from the area.

Water Resources

The Corn Creek Irrigation District would divert waters from the Laramie and North Platte rivers for irrigation of approx­ imately 15,000 acres of land in Goshen County. An average annual water demand of 32,600 ac-ft is projected for the District. The major portion (22,500 ac-ft) of the water supply for Corn Creek would come from the existing Grayrocks Reservoir on the Laramie River. The additional 10,100 ac-ft of water would be delivered from the Bureau of Reclamation's Glendo Reservoir.

Return flows from the District, under a sprinkler irrigation system, are expected to be minimal or non-existent. The regional hydrogeologic conditions indicate that groundwater gradients slope to the southeast, parallel with or away from the North Platte River (Wyoming State Engineers Office, 1971; High Plains Underground Water Conservation District, 1981). The local groundwater table is also 200 to 400 feet below the ground surface, and bedrock in the area is primarily slowly permeable sandstones and siltstones. Therefore, the water that is lost into the ground at the District will probably not return to the North Platte River. There will be minimal surface runoff from the sprinkler system, and the District has no effective means to control this water prior to its potential return to the North Platte River. Return flows, therefore, were not assumed to mitigate the river depletions and no credits were allowed in the calculations estimating North Platte depletions due to the project.

Under the terms of the District Court Agreement for construc­ tion of the Grayrocks Reservoir, the MBPP is obligated to deliver 11,250 ac-ft of replacement water to the Platte River system when the Corn Creek Irrigation District becomes opera­ tional. Basin Electric Power Cooperative was contacted during the preparation of this environment assessment, and they

IV-3 confirmed their commitment for this replacement water. How­ ever, they apparently have no firm plans at this time with respect to the replacement location(s) or schedule. Basin Electric stated that the replacement water may come from existing water rights or rights acquired in the future. To estimate Platte River depletion impacts for the ccrD project, the 11,250 ac-ft of replacement water was assumed to be returned at either the confluence of the North Platte and Laramie Rivers, or the Wyoming-Nebraska State line. The replacement water was assumed to be delivered at a uniform rate throughout the 12 months of the year.

The schedule for water releases from Grayrocks and Glendo Reservoirs to supply the CCID project, the planned CCID withdrawal schedule, and assumed schedule for the MBPP replacement water are shown in Table 8. Based on the schedule of water releases and demands, the net depletion of 21,350 ac-ft (32,600 ac-ft demand minus 11,250 ac-ft of replacement water) would impact the North Platte River pri­ marily during the irrigation season of May through September.

Laramie River and North Platte River flows for the years 1941 through 1977 were used as a data base for calculating depletions due to the Corn Creek project (Water and Power Resources Service, 1980). Laramie River flows at the project site averaged 80,500 ac-ft per year during this 37-year period while North Platte River flows averaged 428,200 ac-ft per year (Table 9). Depletions due to the project were estimated at three locations on the North Platte River; immediately below the project (referred to as Fort Laramie), at the Wyoming-Nebraska state line, and at Lewellen, Nebraska just upstream of Lake McConaughy. No depletions will occur on the Laramie River because the CCID diversion point will be at the confluence of the Laramie and North Platte Rivers. Likewise, no depletions for CCID will occur on the North Platte River between Glendo Reservoir and the mouth of the Laramie River.

Irrigation water that eventually feeds into Nebraska is diverted from the North Platte River at the Whalen Diversion Dam (Interstate Canal) about 10.5 miles upstream of the CCID project. The development of Corn Creek will not influence the Nebraska irrigation allotments, and will not deplete North Platte River flows at or above Whalen Dam. Therefore, the CCID project will not impact the Nebraska irrigation commitments, and will not impact subsequent water flows into inland lakes in western Nebraska and into tributary streams north of the North Platte River in Nebraska.

Tables 10 and 11 present the calculated annual depletions of the North Platte River flows for the 1941-1977 period, assum­ ing the 11,250 ac-ft of replacement water is returned either at the confluence of the North Platte and Laramie Rivers (at

IV-4 Table 8 SUMMARY OF WATER RELEASES FROM STORAGE RESERVOIRS, WATER WITHDRAWALS BY CCrD,. AND RESULTANT FLOW CHANGES DOWNSTREAM OF THE CCrD (Flows Presented as cubic feet per second)

AEril Ma;t-SeEt Oct Nov-Mar a Release at Glendo b 0 34 0 0 Release at Grayrocks 42 21 21 c 42 Withdrawal at CCrD d 42 75 21 21 MBPP Replacement water 15.8 15.8 15.8 15.8 Net Depletion Down- stream of CCID 26.2 59.2 5.2 5.2 a 10 ,100 ac-ft supplied to ccrD from Glendo Reservoir, May-September. b 15 ,000 ac-ft supplied to ccrD from Grayrock Reserovir, April- September, and 7,500 ac-ft supplied to ccrD from Grayrocks, October-March. CWater withdrawals at ccrD during non-irrigation season of October thru March pumped into the Teeters Reservoir and stored. dAssumes 11,250 ac-ft of replacement water added to the Platte River by MBPP equally through the year.

DE/27R/150

IV-5 Table 9 LARAMIE RIVER AND NORTH PLATTE RIVER FLOWS DURING THE 37-YEAR PERIOD 1941 through 1977 (1, 000 ac-ft)

Laramie River North Platte Laramie River at River at as Percent of --Year Ft. Laramie Ft. Laramie North Platte 1941 30.1 346.6 8.7 1942 84.6 524.0 16.1 1943 80.7 394.6 20.5 1944 20.9 326.7 6.4 1945 82.0 400.4 20.5 1946 34.5 269.8 12.8 1947 123.8 346.7 35.7 1948 58.9 314.3 18.7 1949 89.2 319.6 27.9 1950 35.8 293.2 12.2 1951 52.2 259.3 20.1 1952 85.8 557.4 15.4 1953 29.1 254.0 11.5 1954 15.2 150.0 10.1 1955 27.2 173.8 15.7 1956 33.5 379.1 8.8 1957 88.5 333.8 26.5 1958 79.8 321.4 24.8 1959 66.5 309.5 21.5 1960 39.8 298.3 13.3 1961 46.6 242.6 19.2 1962 82.4 321.7 25.6 1963 49.3 338.4 14.6 1964 54.9 338.8 16.2 1965 73.6 421.1 17.5 1966 45.0 340.2 13.2 1967 86.2 341.3 25.3 1968 105.8 442.7 23.9 1969 57.5 375.8 15.3 1970 150.3 465.9 32.3 1971 377.0 1,349.6 27.9 1972 89.9 601.2 15.0 1973 341.3 1,583.4 21.6 1974 99.8 1,022.9 9.8 1975 53.0 416.2 12.7 1976 63.4 359.8 17.6 1977 46.0 309.4 14.9

AVERAGE 80.5 428.2 18.1

Source: Point Flow Study, North Platte River, 1941-1977. Water and Power Resources Service, July 1980.

DE/23R/137

IV-6 Table 10 NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIEi

1000 AC-FT UNITS a b a b RE':ORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1941 303.7 31213.7 346.6 329. l~ 1942 419.4 419.4 524.0 502.7 1943 279.3 279.3 394.6 37S.Ql 1944 288.5 288.5 326.7 31121.5 1945 302.7 31212.7 40121.4 380.5 1946 221.6 221.6 269.8 256.4 1947 214.121 214.121 346.7 329.5 1948 233.5 233.5 314.3 298.7 1949 215.1 215.1 319.6 31213.7 195121 240.2 24121.2 293.2 278.6 195 t 196.1 196.1 2'59.3 246.4 1952 459.3 459.3 557.4 536.1 1953 213.8 213.8 254.121 241 • i~ 1954 128.5 128.5 15121.121 142.5 1955 133.4 133.4 173.8 165.2 1956 242.7 242.7 279.1 2,~5. 2 1957 239.5 239.5 333.8 317.2 1958 235.0 235.0 321.4 3iD5.4 1959 236.2 236.2 31219.5 294.1 196121 249.3 249.3 298.3 283.5 1961 193.4 193.4 242.6 23Q).5 1962 235.5 235.5 321.7 305.7 1963 282.9 282.9 338.4 321. f.-, 1964 277.4 277.4 338.8 321.9 1965 34121.1 34121.1 421.1 400.'.:::: 1966 289.3 289.3 340.2 323.3 1967 251.2 251.2 341.3 324.3 1968 333.7 333.7 442.7 4'-"..;;,J..'+ , 1969 31121.8 310.8 375.8 357. ~ 1970 318.7 318.7 465.9 444.,~ 1971 9~6.7 966.7 1349.6 1328.:-=; 1972 504.7 51214. 7 601.2 579.9 1973 1237.6 1237.6 1583.4 1562. 1. 1974 898.1 898.1 112122.9 !~01.6 197 5 344.6 34~.6 416.2 39=. 'J <:;) :"'~7.~ 285.3 235.3 359.8 .~,,+ 1. 1977 255.6 255.6 3~9.4 294.0

TOTAL 12377.4 12377.4 15743.5 15115.7

AVERAi.=.iE 334.5 334.5 425.5 4~]8. 5

~. Source: Point r j,QljJ Stud!:.!, North Platte River, W!:.!oming - Nebr.5.sk:a" Wat~r and POI.IJer Resources Service, J'..ll!:.! 198~.

b FloUJ ~.djIJstmen ts l.lJ~re made using simulated depletions from 2·~.nner and Associates Gr~.!:::i Racks Operation Stud!:.! GRGF09.

IV-7 Table 10 (continued) NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1941 468.9 451.2 758.8 755.5 1942 707.5 686.3 1306.8 1301.1 1943 554.1 533.2 991.0 986. 'S 1944 492.4 473.9 1048.8 1044.2 1945 599.5 578.2 1250.2 1244.7 1946 483.4 465.2 996.7 992.3 1947 553.5 532.7 1266.2 1260.6 1948 596.8 575.5 1137.0 1132.0 1949 504.9 485.9 1128.4 1123.4 1950 473.0 455.2 1066.9 1062.2 1951 437.3 420.8 1173.6 1168.4 1952 722.1 700.8 1237.2 1231. 8 1953 407.2 391.9 941.8 937.7 1954 262.0 252.1 624.0 621.3 1955 219.7 211. 4 661.6 658.7 1956 300.8 289.5 576.0 573.5 1957 382.9 368.5 873.2 869.4 1958 380.8 366.5 934.6 930.5 1959 368.5 354.6 776.4 773.0 1960 329.2 316.8 605.4 61212.7 1961 292.0 281.121 648.7 645.9 1:;1 ••-:. '"7 1962 383.1 368.7 916.3 1.1...... , 1963 378.2 364.0 813.7 810. L 1964 382.5 368.1 685.2 682.2 ::'965 480.9 462.8 1089.0 1.084.2 1966 393.8 379.121 880.1 876.2 1.967 399.9 384.8 925.4 921.3 1968 483.9 4,~5. 7 996.8 992.4 1969 429.6 413.4 892.6 888. 7 1970 254.7 245.1 Hl36.3 1031.7 1971 1453.2 1431.9 2040.5 203:.5 1972 648.0 626.7 1195.7 1190.4 1973 1659.0 1637.7 2305.4 2295.3 1974 1085.S 1e.~4. 2 1615.8 1608. ( 1975 455. , 4:"38.5 q36.1 932. ~~ 1'7'7,~ 417,. 7 4v.12.Qi 888.7 884.:3 1977 350.2 337.~ 788.4 784. 9

TOTAL 19192.4 18580.9 38009.3 37842.3

Al./ERAGE 518. I 502.2 1027.3 1022.8

.;. Source: Point Flow Sb.J.dl:l, Nortri Pl~tte River, Wl:Ioming - Nebre.ska, Water and POl.lIer Re'5ol.J.r'-~s Service, Jl.J.l!.:f 1980.

b Flow .adj'.J.stmel"\ts '.!Jere made LI.S i n9 simulated depletions from :E,anner and A'5soc:iat~s Gra!.:f Rocks (ipel"a.tioT'\ Stud!:; GRGF09.

IV-8 Table 11 NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a b RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1941 303.7 303.7 346.6 320.0 1942 419.4 419.4 524.0 491. 4 1943 279.3 279.3 394.6 364.3 1944 288.5 288.5 326.7 299.8 1945 302.7 302.7 400.4 369.8 1946 221.6 221.6 269.8 245.7 1947 214.0 214.0 346.7 318.8 1948 233.5 233.5 314.3 288.0 1949 215.1 215.1 319.6 293.12) 1950 240.2 240.2 293.2 267.9 1951 196.1 196.1 259.3 235.7 1952 459.3 459.3 557.4 524.3 1953 213.8 213.8 254.0 230.7 1954 128.5 128.5 150.0 131. 8 1955 133.4 133.4 173.8 154.5 1956 242.7 242.7 279.1 254.5 1957 239.5 239.5 333.8 306.5 1958· 235.0 235.0 321.4 294.7 1959 236.2 236.2 309.5 283. 1+ 1960 249.3 249.3 298.3 272.8 1961 193.4 193.4 242.6 219.8 1962 235.5 235.5 321.7 295.~ 1963 282.9 282.9 338.4 3leJ.9 1964 277.4 277.4 338.8 311.3 1965 340.1 34€.1 421.1 389.5 1966 289.3 289.3 340.2 312.6 1967 251.2 251.2 341.3 313.6 1968 333.7 333.7 442.7 410.0 1969 310.8 310.8 375.8 346.1..- 1970 318.7 318.7 465. 9 433.3 1971 966.7 966.7 1349.6 1317.Vl 1972 504.7 504.7 601.2 568.6 1973 1237.6 1237.6 1583.4 1 '550 J3 1974 8°8.1 898.1 1022.9 S·9~. :3 1 c;'75 344.6 344.6 416.2 38-4. ;':; :97.~ 285.3 285.3 359.8 331 a: 1977 255.6 255.6 309.4 283. :3

TOTAL 12377.4 12377.4 15743.5 14716.~

AVERAGE 334.5 334.5 425.5 397.

~. SOlJ.rc::: P<::lir.t Fl'::lW Shldy, North Platte River, W!:,!oming - Nebraska, Water .and POI!!er R~s'::lu,rces Service, July 1980. b FlolJl .;.jjustrnents were m.ade using ;;imuia.ted depletions fram ?anner and AS'5ljciates Gray R'::lcks Opera.tion St'-ld~ GRGFVl9.

IV-9 Table 11 (continued) NORTH PLATTE RIVER FLOWS WITH AND WITHOt:.JT THE CORN CR~EK PROJECT AT SELECTED SITES (WITH 11,2513 AC-FT REPLACEMENT WATER AT STATE LINE)

113130 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD.rUSTED STATE LINE FLOWS LEWELLEN FLOWS

1941 468.9 451.8 758.8 755.5 1942 707.5 686.2 1306.8 1301.1 1943 554.1 533.8 991.13 986.6 1944 492.4 474.4 11348.8 1044.2 1945 599.5 578.2 12513.2 1244. 7 1946 483.4 465.7 996.7 992.3

1947 553.5 5"-'oJ~.";;''-. 1266.2 1260.6 1948 596.8 575.5 1137.13 1132.13 1949 5134.9 486.4 1128.4 1123.4 19513 473.0 455.7 112166.9 11362.2 1951 437.3 421.4 1173.6 1168.4 1952 722.1 7013.8 1237.2 1231. 8 1953 407.2 392.4 941.8 937.7 1954 262.~ 252.7 624.13 621.3 1Q C:C: , ~.J 2t9.7 211. 9 661.6 658. 7 1956 3130.8 290.0 576.0 573.5 1957 382.9 369.0 8-"(,...,J • .-...:. 869. it- 1958 3813.8 367.0 934.6 930.5 1959 368.5 3S5.1 776.4 773.~ 19613 329.2 317.3 6135.4 602.7 1961 292.0 281.5 648.7 645.9 "'7 ' C) .",:, 1962 383.1 ,JO I • ..:.. 916.3 912.3 1963 378.2 364.5 813.7 810.1 1964 382.5 3,~8.6 685.2 ,:;82.2 1965 4813.9 463.3 112189.121 112184.2 1966 393.8 379.5 880. 1 876.2 1967 399.9 385.4 925.4 921. ::; 1968 483. 9 466.2 996.8 992.4 19.:S9 429.6 413.9 892.6 888.7 19712) 254.7 245. ,~ 1036.3 lS31.7 1971 14'53.2 1431.9 2040. 5 2031.5 1972 648.121 626.7 1195. I 1190.4 1973 1659.el 1637.7 2305.4 229::.:3 1=174- 1085.5 10·~4. "2 1615.8 1608. 7 '7 197:; 4==...J...J. 43S·.1 936. 1 932.c:'} 197b 417.7 402.5 888. i 884.8 1977 3513.2 1-:""

TOTAL 19192.4 18595.7 381309.3 37842.3

AI./ERAGE 5t8.7 502.6 1027.3 1022. :J a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Wat~r and Power Resources Service, July 1980. b Flew adjustments were made using simulated depletions from Ban~er and Associates Gray Rocks Operation Study GRGF09.

IV-IO Ft. Laramie, Table 10) or at the Wyoming-Nebraska state line (Table 11). North Platte River flows on a monthly basis for the "with project" and "without project" scenarios are pre­ sented in Appendix B. The calculated impact of the CCID diversions on river flows demonstrates the net effect of the proposed project's operation and the buffering of that impact with distance downstream. The depletions immediately down­ stream of the project represent only a 4 to 6.5 percent reduc­ tion in annual North Platte flows, depending upon whether the 11,250 ac-ft of replacement water is replaced at the project site or further downstream. The depletion impact on the North Platte River just above Lake McConaughy represents less than 1/2 of one percent of the recorded flows at Lewellen, Nebraska.

The Laramie River. Grayrocks Reservoir on the Laramie River was completed in the early 1980's to provide cooling water for the Laramie River Generation Station (or MBPP) near Wheatland, Wyoming. The reservoir was also designed to provide water to the CCID when it becomes operational. The releases to the Laramie River to meet the CCID demands would be as follows:

April to September 15,000 ac-ft October to March 7,500 ac-ft Annual 22,500 ac-ft

Since the Corn Creek diversion point would be located at the confluence of the Laramie and North Platte rivers downstream of Grayrocks Reservoir, there would be no reduction in flows in the Laramie River as a result of con­ struction of the Corn Creek project. The Laramie River would be used to convey flows from Grayrocks Reservoir to the District. Under present conditions, annual releases from Grayrocks Reservoir total approximately 34,000 ac-ft at the mouth of the Laramie River. This flow would satisfy CCID water requirements with only small changes in monthly discharge schedules. And, as previously stated, once Corn Creek is constructed and utilizing 22,500 ac-ft annually from Grayrocks, the MBPP must also supplement flows in the Platte River by an additional 11,250 ac-ft from an unspeci­ fied source. From a practical standpoint, it is likely that these flows would be added to the river system somewhere upstream of the Nebraska-Wyoming state line. However, the Agreement does not specify where the replacement is to take place.

The North Platte River Upstream of Lake McConaughy. The CCID would divert water from the North Platte River system utilizing 10,100 ac-ft of water presently stored but uncom­ mitted in Glendo Reservoir, and the 22,500 ac-ft from Gray­ rocks Reservoir. The Glendo water would be delivered on a prearranged schedule during May through September, because

IV-11 the Court Decree mandates that this water is released only during the irrigation season. The water from Grayrocks Reservoir would be delivered over 12 months according to the schedule given in Table S.

The depletions on the North Platte River due to the CCIO Project were estimated at three locations between the project and Lake McConaughy in western Nebraska (Tables 10 and 11). As previously stated, if the 11,250 ac-ft of MBPP replacement water is put into the river at the project, then the average annual flow of the North Platte is reduced by only 4 percent at Fort Laramie, from 425,500 ac-ft to 408,500 ac-ft. The percent reduction is smaller during wet years, and would vary from 1.4 percent to 5.0 percent based on the 1941 to 1977 period of study. If the MBPP replacement water is put into the North Platte farther downstream, then depletions immediately below the project would average 6.5 percent of the annual North Platte flow, and range between 2.1 percent and 12.1 percent (Tables 10 and 11).

The average annual flow at the Wyoming-Nebraska state line over the 37-year period of study was 51S,700 ac-ft. With the CCIO project in operation, this flow would be reduced around 3 percent. The range of depletions during wet and dry years is estimated to be between 1.3 percent and 3.S per­ cent (Tables 10 and 11). Flow reductions at the Wyoming­ Nebraska state line are not much different under the two MBPP replacement water scenarios.

Due to transportation losses and other gains and losses between the project and Lewellen, Nebraska, the net deple­ tion due to ccrD at Lewellen represents only a 0.4 percent reduction in annual flows. This holds true for both MBPP replacement scenarios. Therefore, depletions due to the ccrD project are essentially too low to accurately measure on the North Platte River as it flows into Lake McConaughy in western Nebraska.

The impact of CCIO depletions on monthly flows in the North Platte River for each year during the 1941-1977 period are presented in Appendix B. Tables 12 and 13 present these monthly depletion data for an average flow year (1975), a wet year (1974), and a dry year (1953) at Fort Laramie and at the state line. Since the depletions at Lewellen, Nebraska are very low (less than 0.5 percent during most months) no summary table was constructed for the Lewellen location (see Appendix B for these data) .

Although the largest depletions, in terms of ac-ft, occur during the summer months, the depletion impacts, in terms of percent reduction in river flows, are usually lowest during the SUIT~er because river flow rates are higher in the su~~er. The percent reduction in flows immediately downriver of the

IV-12 Table 12 a MONTHLY NORTH PLATTE RIVER FLOWS AND EXPECTED DEPLETIONS AT FORT LARAMIE DUE TO THE CORN CREEK PROJECT DURING AVERAGE,' WET, AND DRY YEARS (1,000 ac-ft)

b c c Avera2e Flow Year - 1975 Wet Flow Year - 1974 Drl Flow Year - 1953 De~letion with Re~lacement at De~letion with Re~lacement at De~letion with Re~lacement at Recorded Fort Laramie State Line Recorded Fort Laramie State Line, Recorded Fort Laramie, State Line, Month Flow ac-ft , ac-ft , Flow ac-ft , ac-ft Flow ac-ft - ac-ft Jan 8.2 0.8 9.8 1.2 14.6 13.8 0.8 5.9 1.3 9.4 3.8 0.5 13.2 0.9 23.7 Feb 8.5 0.8 9.4 1.2 14.1 15.8 0.8 5.2 1.3 8.2 3.1 0.5 16.1 0.9 29.0 Mar 8.7 0.8 9.2 1.2 13.8 258.6 0.8 0.3 1.3 0.5 3.7 0.5 13.5 0.9 24.3 Apr 22.1 1.6 7.2 2.4 10.9 245.2 1.6 0.7 2.5 1.0 6.8 1.0 14.7 1.8 26.5 May 32.0 3.0 9.1 4.3 13.4 94.8 3.0 3.1 4.5 4.7 23.3 1.7 7.3 3.2 13.7 Jun 57.1 3.0 5.1 4.3 7.5 154.6 3.0 1.9 4.5 2.9 40.2 1.7 4.2 3.2 8.0 Ju1 123.9 3.0 2.3 4.3 3.5 113.6 3.0 2.6 4.5 4.0 73.8 1.7 2.3 3.2 4.3 Aug 84.3 3.0 3.4 4.3 5.1 70.1 3.0 4.1 4.5 6.4 48.6 1.7 3.5 3.2 6.6 Sep 31.1 3.0 9.3 4.3 13.8 21.3 3.0 13.6 4.5 21.1 32.7 1.7 5.2 3.2 9.8 Oct 18.2 0.8 4.4 1.2 6.6 16.4 0.8 4.9 1.3 7.9 8.0 0.5 6.3 0.9 11.3 Nov 11.5 0.8 6.9 1.2 10.4 10.1 0.8 7.9 1.3 12.9 6.9 0.5 7.2 0.9 13.0 Dec 11.1 0.8 7.2 1.2 10.8 8.3 0.8 9.6 1.3 15.7 ~ 0.5 14.3 0.9 25.7 TOTAL 416.2 21.4 5.0 31.4 7.5 1,022.9 21.4 2.1 32.8 3.2 254.0 12.5 5.0 23.3 9.2 H <: I VJ aFlow adjustments were made using simulated depletions from Banner and Associates Operation Study GRGF09 and the expected monthly withdrawal schedule for eeID (Table 8). bA year during the 1941-1977 period that is close to the average annual flow at Fort Laramie during the 37-year period. cA year in the upper (wet) or lower (dry) quartile, but not the wettest or dryest years that represent unusual extremes. Source: Point Flow Study, North Platte River, 1941-1977. Water and Power Resources Service, July 1980.

DE/23R/138 Table 13 a a MONTHLY NORTH PLATTE RIVER FLOWS AND EXPECTED DEPLETIONS AT THE WYOMING-NEBRASKA STATE LINE DUE TO THE CORN CREEK PROJECT DURING AVERAGE, WET, AND DRY YEARS (1,000 ac-ft)

b c c Avera~e Flow Year - 1975 Wet Flow Year - 1974 Drr Flow Year - 1953 De~letion wIth Re~Iacement at De~ietion witb ReElacement at De~letion with Re~IacemenE at Recorded Fort LaramIe State Line Recorded Fort Laramie State Line Recorded Fort Laramie State Line Month Flow ac-ft - % ac-ft - % Flow ac-ft - % ac-ft - % Flow ac-ft ac-ft " Jan 18.6 0.7 3.8 0.6 3.2 26.1 0.8 3.1 0.8 3.1 32.1 0.6 "1.9 0.6 1.9 Feb 15.8 0.7 4.4 0.6 3.8 23.5 0.8 3.4 0.8 3.4 27.7 0.6 2.2 0.6 2.2 Mar 18.1 0.7 3.9 0.6 3.3 258.4 0.8 0.3 0.8 0.3 29.4 0.6 2.0 0.6 2.0 Apr 25.8 1.3 5.0 1.3 5.0 262.2 1.6 0.6 1.6 0.6 19.5 1.2 6.2 1.0 5.1 May 29.3 2.4 8.2 2.3 7.8 94.6 2.9 3.1 2.9 3.1 27.7 2.1 7.6 2.0 7.2 Jun 50.4 2.4 4.8 2.3 4.6 140.2 2.9 2.1 2.9 2.1 41.1 2.1 5.1 2.0 4.9 Ju1 125.9 2.4 2.3 2.3 2.2 96.9 2.9 3.0 2.9 3.0 65.9 2.1 3.2 2.0 3.0 Aug 74.8 2.4 3.2 2.3 3.1 68.1 2.9 4.3 2.9 4.3 51.6 2.1 4.1 2.0 3.9 Sep 42.5 2.4 5.6 2.3 5.4 37.3 2.9 7.8 2.9 7.8 42.0 2.1 5.0 2.0 4.8 Oct 31.3 0.7 2.2 0.6 1.9 33.0 0.8 2.4 0.8 2.4 26.7 0.6 2.2 0.6 2.2 Nov 22.6 0.7 3.1 0.6 2.7 23.9 0.8 3.3 0.8 3.3 22.7 0.6 2.6 0.6 2.6 Dec 20.6 0.7 3.4 0.6 2.9 21.3 0.8 3.8 0.8 3.8 20.6 0.6 2.9 0.6 2.9 H

DE/23R/139 project usually does not exceed 15 percent and, if the MBPP replacement water enters the river at the project the percent depletion usually does not exceed 10 percent. As expected, the highest percent reductions in flow occur during the driest years, and during the months with the lowest flows. For example, during 1953, one of the driest years between 1941 and 1977, the percent reductions in flow ranged between 11.3 percent and 29.0 percent during the winter and early spring months. These calculations are based on the worst case assumption that the MBPP replacement water enters the river at the state line (Table 12). During one of the wettest years of record, 1974, the percent reduction in monthly flows was usually less than 5 percent (Table 12). The depletion impacts at the state line are shown in Table 13, and the flow reductions are usually less than 5 percent and frequently less than 3 percent even during dry years.

As a part of the environmental approval process for the MBPP, a Final and a Supplemental Environmental Impact Statement (FEIS and SEIS) were prepared. These reports had a primary objective of identifying the impacts that the Laramie River Generating Station and Grayrocks Reservoir would have on the Platte River (REA, 1976 and 1980). The SEIS also was designed to determine the cumulative impact that all planned projects, including the Corn Creek Irrigation Project, would have on the downstream hydrology of the Platte River system. The SEIS, however, did not consider the 11,250 ac-ft of replace­ ment water that would be delivered by MBPP to the Platte River. The assessment of hydrologic impacts resulting from the operation of Corn Creek that are expressed in the SEIS, basically agree with the results shown in Tables 12 and 13, if the SEIS findings are adjusted to account for the MBPP replacement water.

The impact of water withdrawals by CCID on the North Platte River at the Wyoming-Nebraska state line, at Bridgeport, Nebraska, and at Lewellen, Nebraska just upstream of Lake McConaughy was estimated in the SEIS using the Operation Study No. 14 (REA, 1980). The Operation Study No. 14 assumes conveyance losses of 1/4 to 1/2 percent per mile, and the depletion at Lewellen just upstream of Lake McConaughy amounts to 8,800 ac-ft. If the operations model had considered the ~~PP replacement water, and the additional use of Glendo Reservoir water, the net depletion immediately upstream of Lake McConaughy would be around 3,500 ac-ft. This compares favorably with the estimated depletion of 4,500 ac-ft at Lewellen, Nebraska shown in Appendix B.

The SElS also presented the relative impact of the reduced flows on average water depths at various points in the river system. At Lewellen, for instance, where the average water depth varies between 1.4 and 0.8 feet, the projected reduction in depth due to Corn Creek was calculated to be

IV-IS 0.01 feet. As explained above, this is an overestimate. Therefore, the CCID depletions would have a negligible impact on water depths at Lewellen.

Lake McConaughy. This lake is the largest body of water in Nebraska with a surface area of 30,500 acres and volume of 1,792,500 ac-ft at the current maximum operating level of 3,265 feet (msl). The function of Lake McConaughy is to provide agricultural water to downstream irrigation districts and to produce hydroelectric power. The lake, owned and operated by Central Nebraska Public Power and Irrigation District (CNPP&ID), fills during the nonirrigation season (fall and winter) and reaches maximum storage by the fol­ lowing May.

The impacts of CCID diversions on flows upstream of Lake McConaughy have been estimated by the Operations Study No. 14 and by estimating net depletion in flow rates for the North Platte River below the Corn Creek Project (Tables 10 through 13 and Appendix B). The impacts on Lake McConaughy and downstream are not so easily defined because of the lack of definitive lake operation data. Water is discharged from Lake McConaughy to meet irrigation demands and hydroelectric power requirements. Otherwise, inflows into the lake are retained in the reservoir, except for intentional spilling when the lake approaches a maximum operational level mandated by the Federal Energy Regulated Commission (FERC) to prevent excessive shore erosion.

Since water is spilled during many wet years at Kingsley Dam to maintain the proper operational level of Lake McConaughy, the most significant effect of CCID withdrawals during wet years would be a reduction in the amount of water spilled from the lake. Whenever possible, this surplus water is spilled during the nonirrigation season. This would be an operational consideration and is not dependent on any legal agreement between CCIO and the Lake McConaughy operators. During a wet year, the entire depletion of inflow to Lake McConaughy due to CCIO operation (estimated at 4,500 ac-ft, Appendix B) would be passed downriver as a reduction in the non-irrigation season spillage. Therefore, the CCIn with­ drawal should have no impact on the lake during wet years. During a dry year when no spillage occurs, the depletion due to CCIn would result in an insignificant decrease in the maximum lake level, because the CCID withdrawal represents about 0.25 percent of the volume of Lake McConaughy at a lake elevation of 3,265 feet (msl). During average water years, the impacts associated with the operation of CCID would be observed as a reduction in flows downstream of Kingsley nam as the non-irrigation season spillage is reduced, or perhaps a compromise between reduced spillage and a minor reduction in lake level.

IV-16 Reduced lake levels would be a concern during extended low flow periods (drought conditions). The Operation Study No. 14 indicated that a recurrence of the 1953-1956 drought conditions on the Platte River system and Lake McConaughy would produce a minimum storage level of about 259,000 ac-ft, compared to a historic low reservoir volume of 383,000 ac-ft in October 1956. This estimate was based upon the 1980 level of development and current operating criteria. That is, no change in the operation of Lake McConaughy was assumed. Historically, the operator of Lake McConaughy has not re­ duced outflows during a low flow period because the project is designed for downstream irrigation and to supplement low flow periods. However, if all of the upstream projects presently under consideration are built, Lake McConaughy would experience lower storage levels during a recurrence of a drought period similar to that which occurred in 1953-1956, unless downstream releases were reduced.

The Platte River Downstream of Lake McConaughy. As men­ tioned previously, predicting the impact of the CCID on flows downstream of Lake McConaughy depends entirely on how the lake is operated. With minor changes in the operation of Kingsley Dam, all of the impacts of ccrD withdrawals could be limited just to the lake (except in the case of extended low flow periods) or result in a slight reduction in the amount of surplus water spilled from the lake in the non­ irrigation season. Regardless of the operational assumptions that are made, Tables 10 through 13 and Appendix B show that the impact of Corn Creek is very small at Lewellen, Nebraska, above Lake McConaughy. And, the CCID depletions below Lake McConaughy are too low to accurately measure. The SEIS for the MBPP estimated the CCID depletions at Overton, Nebraska (just upstream of the Whooping Crane Critical Habitat Area) represent a reduction of 0.6 percent in the recorded flows at that location. When the 11,250 ac-ft of replacement water from MBPP is added the impact would be reduced to much less than 0.6 percent. In contrast, additional future groundwater pumping in Nebraska represents a reduction of 12.5 percent of present flow levels in the Platte River near Overton, or over 20 times the impact of Corn Creek (REA, 1980).

The impact of flow reductions in the Platte River below Lake McConaughy, due to upriver depletions by CCID, could be reduced to near zero by modifying the schedule of outflows from Lake McConaughy. Since the depletions by CCID repre­ sent a small percentage of the volume of water in Lake McConaughy, the impacts of CCID depletions could be limited to the lake during normal or drier than normal years. Then, during wetter than normal years flows through Kingsley Dam could be reduced to compensate for the CCID depletion impact on the lake, and still provide the existing level of flow required downstream in the Whooping Crane Critical Habitat in central Nebraska.

IV-17 Considering the need to protect legally vested water rights in downstream areas, the hydrologic impacts from CCIn opera­ tion would be expected to be noticeable only during extreme drought conditions. During average or wet years the depletion due to CCID would be expressed as a nominal reduction in nonirrigation season flows downstream of Lake McConaughy. During a dry year, flows downstream of Lake McConaughy would be the same as they are under present conditions, and the depletion due to CCID would be absorbed by the lake. There­ fore, water depletions by CCID would be expected to impact Platte River flows below McConaughy only if there is an extreme drought condition.

2. BIOLOGICAL COMPONENTS

Vegetation

The Teeters Reservoir would inundate about SOD acres of land in the Cherry Creek watershed, replacing terrestrial vegetation with a fluctuating reservoir. The reservoir site is presently pasture land and the lost vegetation would include short-grass prairie composed primarily of blue gramma and buffalo grass. A very thin strip of riparian habitat along about one mile of the intermittent creek would also be flooded (Wyoming Game and Fish Department, 19S4). The existing creek bottom is a narrow intermittently wet meadow consisting of various grasses, rushes, and sedges. The riparian zone also contains widely scattered patches of small cottonwood trees and willows.

To offset the loss of riparian habitat, the Cherry Creek bottomland below the dam would be revegetated to enhance wildlife and replace the lost riparian vegetation. A small stand of cottonwoods exists just downstream of the proposed dam sit~. This area would be protected during dam construc­ tion, and the riparian habitat expanded in this area after the dam is in place. Water would be supplied to the area below the dam as a result of natural seepage, augmented by small releases from the reservoir if necessary. Seepage from Teeters Reservoir is expected to be about 700 acre-feet or more per year. Small cottonwoods and willows within the reservoir site would be transplanted, if appropriate, to creek bottomlands just below the dam. Additional cottonwoods and Russian olive trees, plus shrubs such as chokecherry and current could be added to enhance wildlife.

The one-mile long dam would be revegetated with native short­ grass prairie species along the darn crest and sloping face, and shrubs would be planted along the creek at the base of the dam and on slopes below the dam where water would be adequate to maintain shrubs. The sloping face of the dam and the expanded riparian habitat below the dam would be fenced to exclude grazing cattle. The Corn Creek District is comrrlitted to work with the Wyoming Game and Fish

IV-IS Department, the USFWS, and the Soil Conservation Service to replace, acre-for-acre, the riparian vegetation and good wildlife habitat inundated by the reservoir. Also, after project approvals and funding have been acquired, and before the final design phase, the ccrD would work with the state and federal agencies to define specific mitigation plans; including types and densities of vegetation to be planted, target acreages, fencing requirements, and wildlife manage­ ment obligations.

The ccrD would work with the Wyoming Game and Fish Depart­ ment, the USFWS, and the Soil Conservation Service (SCS) to investigate alternatives for enhancement of wildlife habitat around the reservoir. However, since the water level within the reservoir would vary widely as water is stored and then used for irrigation, the opportunity to develop satisfactory wildlife habitat will be limited. Weeds may become established temporarily on the exposed reservoir bottom when the water level is down. The noxious weeds will be controlled as required by the Goshen County weed and pest control regula­ tions. However, weeds that could be beneficial to wildlife would be left, if possible. The option for the reservoir property, recently acquired by the CCrD, includes about 60 acres of land above the proposed maximum water line. This land would be maintained as short-grass prairie, or could be enhanced for wildlife if a suitable alternative could be worked out with the Wyoming Game and Fish Department and "the USFWS.

The diversion weir on the North Platte River is expected to result in only minor impacts to area vegetation because the small diversion pool would flood only river bottom that floods annually during the spring high water period. Willows and small cottonwoods that might be flooded out by the permanent pool would be transplanted or replaced on District land along the boundaries of the new pool. The CCID would revegetate all areas near the diversion weir that are disturbed during construction of the weir, pump station, and the levee protect­ ing the pump station. The levee protecting the pump station would be reclaimed using native ground cover and grass mix recommended by the SCS. The CCID would acquire the necessary water quality certificate and dredge and fill permit during the final design phase of the project.

The pump station itself would be designed to blend into the natural scenery, or built underground to minimize aesthetic and visual impacts. The cerD would work closely with the National Park Service to minimize any visual impacts to the Fort Laramie Site property across the Laramie River from the pump station. Landscaping techniques using shrubs, levees, or underground construction would be used to reduce noise levels, even though noise impacts are expected to be very minor. Power lines to the pump station would be placed in

IV-19 an existing power line right-of-way so no new visual impacts would be produced. Construction techniques suggested by Olendorff et ale (1981) to protect raptors would be used for upgrading the existing powerline.

The development of 15,000 acres of irrigated cropland would replace primarily fallow land and short-grass prairie with corn, alfalfa, sugar beets, beans, and potatoes. Irrigation machines would include mostly center pivot irrigators, with some continuous-moving linear irrigators. With the center pivot system, and to a lesser extent with the linear irriga­ tors, field borders and corners could be managed to enhance wildlife. The CCID will encourage the landowners within the District to manage some of these areas for wildlife, and to plant shelterbelts for reducing wind erosion and increasing wildlife habitat. Shelterbelts would include shrubs, ever­ green trees, and broadleaf trees. The ses recommends Russian olive, hackberry, green ash, Siberian elm, and cottonwood for broadleaf trees in area shelterbelts. Evergreen trees commonly used include Austrian pine, Eastern redcedar, Rocky Mountain Juniper, or Ponderosa pine. The best shrubs for shelterbelts depends upon the specific soil type at the site, but include chokecherry, lilac, sumac, plum, current, and mountain-mahogany. Runoff from irrigators should be adequate to support shrubs in field corners, along with herbaceous vegetation. Shrubs used for shelterbelts also would be suit­ able species for field corners and fence rows. Shelterbelts and field corners would be fenced to exclude cattle and big game animals such as antelope. The CCID would cooperate with the Wyoming Game and Fish Department and the USFWS dur­ ing the final design phase to develop more specific mitigation plans.

The construction of the buried pipeline and parallel power line will remove vegetation from the pipeline corridor temporarily. However, the width of the construction zone will be restricted as much as possible, and the corridor will be reclaimed using native vegetation or seed mixes recommended by the sese

Wildlife

The Corn Creek Irrigation District does not contain any crit­ ical ranges for the big game animals that are common in the area (Wyoming Game and Fish Department, 1984). Therefore, no major impacts are expected to occur on deer and antelope. In the southern tier of the irrigation development irrigated fields will cover a continuous expanse of land, and the Wyoming Game and Fish Department has expressed some concern regarding travel lanes for antelope in this area. The irrigation develop­ ment will pose very little if any problem with respect to east-west movement in the area. But, the southern tier of irrigated lands could form an unbroken band of fenced fields about 10 to 12 miles long that might hamper north to south

IV-20 movement. The ccrD will consult with the Wyoming Game and Fish Department and one or more travel lanes would be estab­ lished if game movement observations indicate they are needed. Area field studies indicate that big game movement across District lands are probably oriented primarily in an east-west direction.

The increase in acreage of crops (monoculture vegetation) might reduce the diversity of nongame mammals and birds because of the reduced variety of vegetation. However, the development of shelter belts and the increased vegetation density in field corners not actively cultivated on center-pivot plots will enhance these areas for certain birds and small mammals by providing food and cover. The net effect would be some change in species composition but no significant reduction in the general numbers of small mammals' and nongame birds.

No game bird breeding habitats are known in the CCID area and the development will have minimal impact on birds. Ring­ necked pheasants could increase in some local areas with the development of shelterbelts and appropriate vegetation along field borders. The CCID Board will encourage landowners within the District to allow access for upland game bird hunting.

The construction of Teeters Reservoir and maintenance of shallow temporary ponds during the springtime should retain or enhance the area's use by waterfowl. The reservoir will approach maximum pool elevation in the spring and will provide good habitat for waterfowl migrating through the area. Water­ fowl now use temporary snowmelt and spring rain ponds in the area as they move between the Springer Wildlife Refuge south of the District and Grayrocks Reservoir to the west. The waterfowl use the temporary ponds for feeding and resting, and the remote location of these ponds with respect to public roads adds to their utility.

The powerline between the North Platte River and Teeters Reservoir could increase the potential for electrocution of raptors. However, the powerline will be designed to minimize that problem (Olendorff et ale 1981).

The Wyoming Game and Fish Department (1984) anticipates an increase in crop depredation by big game animals if the irri­ gation district is developed. Both deer and antelope will be attracted to lush crops in this otherwise arid area, and the associated damage claims could be costly for the Game and Fish Department. The CCID Board will encourage landowners within the District to work with the Game and Fish Department to minimize these impacts through fencing or other means. However, the depredation problem will not be mitigated entirely and may remain a problem if fencing proves to be economically impractical.

IV-21 The irrigation development will place approximately 15,000 acres of previously unirrigated lands under irrigation. Most of this land is currently fallow or used for dry land wheat, and conversion of these acres will have very little impact on wildlife because these lands support low numbers of wildlife

Three endangered species potentially visit or inhabit the CCID lands: the bald eagle, peregrine falcon, and the black­ footed ferret (U.S. Fish and Wildlife Service, 1984). The bald eagle is a migrant and winter resident in the area. During the winter, the eagles roost and feed along the Laramie and Platte rivers. Their preferred habitat includes zones along the river where there are large trees and open water. They perch in ~he large trees and feed on fish and ducks in the open water areas. If the North Platte diversion weir and pump station are constructed during the winter, the asso­ ciated activity may temporarily reduce the frequency of eagles in the area. However, no long-term impact on bald eagles is expected, and the presence of the diversion weir might even increase the food (fish) availability for eagles. The pere­ grine falcon is a potential migrant only, and the Corn Creek project will not impact this bird of prey.

There are several black-tailed prairie dog colonies adjacent to proposed project lands, and these areas represent potential black-footed ferret habitat. The prairie dog colonies that potentially could be impacted would be surveyed by the Wyoming Game and Fish Department or other qualified biologists one year prior to development, and the survey report would be submitted to the Wyoming Game and Fish Department and the USFWS. The District would work with Wyoming Game and Fish and the USFWS to set aside some colonies as wildlife manage­ ment areas if appropriate. The major prairie dog towns are at least one-half mile from the specific lands planned for irrigated crops, so these towns (colonies) should not be impacted any more than they are under current agricultural practices.

The Big Bend region of the Platte River in Nebraska has been identified as critical habitat for the endangered whooping

IV-22 crane, and the Platte River Whooping Crane Habitat Maintenance Trust was established as a result of development of the MBPP and Grayrocks Reservoir. The habitat requirements for whoop­ ing cranes and sandhill cranes, and the impacts of upstream water developments (diversions) on that habitat, have been thoroughly described by the u.s. Fish and Wildlife Service (1981) and in the MBPP Supplemental EIS (REA, 1980).

The principal impact to crane habitat has been the loss of roosting areas due to the reduction of the broad (100 to 300 meters) open river channel areas because of decreased river flows. Native grasslands where the cranes feed (in addition to croplands adjacent to the river) have also been diminished by decreasing river flows. The whooping cranes require nonforested prairie wetland habitats, including open river channel and sandbar areas for nighttime roosting, sandbar island areas devoid of dense riparian woodland for staging, and wet meadows for staging, foraging, and preening.

The SEIS for the MBPP addressed the potential impacts of the MBPP (including Grayrocks Reservoir) on the whooping crane habitat in Nebraska, and it also addressed the cumulative impacts of the MBPP and the Corn Creek irrigation project (REA, 1980). As a result of that environmental assessment process and resultant court proceedings, the MBPP agreed to the following mitigation requirements:

o The maximum consumptive water use for the power plant at Wheatland (Laramie River Station) was limited to 23,250 ac-ft per year.

o The MBPP will deliver 11,250 ac-ft per year of replacement water into the Platte River system when the Corn Creek irrigation project becomes operational.

o The MBPP established the Platte River Whooping Crane Habitat Maintenance Trust to study crane habitat requirements and maintain critical habitat for the species.

Section IV.A.1 of this report, "Environmental Consequences of the Teeters Reservoir and Diversion Weir Alternative," incorporated the above agreements into calculations for esti­ mating the impact of the Corn Creek Project on Platte River flows in Nebraska. The results, presented in Tables 10, 11, 12, 13, and Appendix B indicate that the ccrD development will have no measurable impact on the Platte River within the Whooping Crane critical habitat area. Water depletions due to CCID are estimated to represent less than one-half of one percent of the North Platte flow upstream of Lake McConaughy, and these minor impacts are further diminished as the water flows through that reservoir.

IV-23 Minor changes in the operation of Lake McConaughy could reduce the impact of Corn Creek water depletions to near zero down­ river of Lake McConaughy. These operational changes would cause minor impacts to Lake McConaughy water levels or hydro­ electric power production. However, because the lake volume is much greater than the proposed Corn Creek water depletions, the change in lake levels would be insignificant. Even if the depletions due to Corn Creek are passed through Lake McConaughy into the Platte River, transportation loses would result in a reduction in river flows within the whooping crane critical habitat area of less than one-quarter of one percent, and a negligible impact on water depths in that stretch of the river. These reductions would occur primarily during the nonirrigation season. No flow reductions would occur in the Whooping Crane Critical Habitat area during the spring migration period when habitat utilization is greatest.

The interior population of the least tern was recently listed as an endangered species throughout the Mississippi River Basin, and the piping plover has been proposed as a candidate species. Both of these birds are present in central Nebraska along Platte River sandbars and beaches, and their nesting habitats have been impacted by channelization and flow deple­ tions. Similar to the whooping crane, the elimination of scouring .of sandbars by high water has made the islands and sandbars in the Platte River unsuitable for nesting by either species. Water depletions due to CCID are estimated to represent less than one-half of one percent of the North Platte River flow upstream of Lake McConaughy, and much less than that below the lake. Therefore, the water depletions due to the project would have a negligible and unmeasureable impact on both water flows and water depths in central Nebraska, and therefore are not expected to impact the interior least tern, the piping plover, or the whooping crane.

Fisheries

Glendo Reservoir and the North Platte River. A minimum pool for fisheries was not included as a project objective during authorization of Glendo Reservoir and Darn. As a result, water level fluctuations and the minimum pool size have been based on water requirements for irrigation and hydroelectric power production. The reservoir, therefore, is subject to severe annual fluctuations as water is stored through late fall and winter and released during the irrigation season. The lowest pool elevations normally occur in Septernher. For the past 5 years, mean minimum storage has been approximately 64,000 ac-ft (Table 2 and Wyoming Game and Fish Department, 1983). This minimum pool is maintained primarily for an acceptable head for generating hydroelectric power.

IV-24 At present, Glendo Reservoir stores 40,000 ac-ft that is allocated for downstream irrigators, and the 10,100 ac-ft currently being requested by CCIn is included within that 40,000 ac-ft. Also, the u.s. Bureau of Reclamation has indi­ cated that the minimum pool size at Glendo would be maintained near existing levels even when the additional near-future water allotments are granted to downstream users (including Corn Creek). Therefore, even through the existing operation schedule at Glendo Reservoir places a moderate stress on the reservoir1s sport fishery (Wyoming Game and Fish Department, 1983), the development of Corn Creek is predicted to have minimal impact on the Glendo Reservoir fishery because it would not change the present operational procedures at the reservoir to any extent. However, if the 10,100 ac-ft from Glendo to CCID is released in a manner that would result in a' minimum pool below existing levels, then potential impacts to the fishery would be addressed (Wyoming Game and Fish Department, 1983).

The North Platte River below Glendo Reservoir is classified as trout waters supporting a fishery of statewide importance (a Class 2 stream) and contains moderate numbers of brown and rainbow trout. However, this river reach is impacted by the operational criteria at Glendo Reservoir. One of the principal impacts is closure of the dam at the end of the irrigation season. During late fall and winter, the only 'flow just below the dam is due to seepage (1-2 cfs), but flows increase to around 30-40 cfs in the river above Guernsey Reservoir due to tributary inflow. Fortunately, the North Platte River in this stretch includes numerous large pools that maintain the trout population over the winter. During the irrigation season, flows in the river range from 100 to over 5,000 cfs (Appendix B) .

The Wyoming Game and Fish Department (1983) has estimated that an additional flow of 40 cfs or less (the projected delivery flows from Glendo to CCrn) during the irrigation season would probably not have a significant impact on the fishery between Glendo and Guernsey Reservoirs. For example, adding 40 cfs to a 1,000-cfs summer flow would only reduce brown trout habitat by less than 2 percent. The water from Glendo Reservoir would be delivered to the Corn Creek devel­ opment during the irrigation season as required by the Platte River Decree, and under that delivery schedule Corn Creek would not affect winter flows in the North Platte between Glendo Reservoir and the ccrD.

The Corn Creek diversion weir on the North Platte River just below its confluence with the Laramie River would form a pool and the weir, depending upon its final design form, could act as a barrier to upstream and downstream fish move­ ment during low water periods. This low-head weir might also divert some sport fish into the Laramie River, but these

IV-25 fish would still be available to the sport fishermen. Also, the pool behind the weir, and the riffle area below the weir during overflow periods, may enhance the fishing success in the weir area. The main negative impact of the weir would be its blockage of upstream or downstream fish movement. During low flow periods, the weir might influence the recrea­ tional fishery in the river between the weir and the Wyoming­ Nebraska state line because downstream movement of fish into that stretch might be reduced. The ccro is continuing to evaluate weir designs that may not result in a barrier extend­ ing all the way across the river. The intake gate at the south end of the diversion weir would be screened to prevent fish loss into the irrigation water system.

During construction of the diversion weir the area fishery and water quality would be temporarily impacted. Turbidity would increase during the period when construction activities actually occur within the river channel, and some areas would be temporarily dewatered. These construction impacts, how­ ever, would only be temporary.

The withdrawal of water from the North Platte River would have some negative impacts on the fishery between the ccro diversion weir and the Wyoming-Nebraska state line. How­ ever, since the major diversions would occur during the summer months when North Platte flows are usually several hundred cfs, the impact to the fishery is expected to be minor. Table 12 indicates that during an average flow year the ccrD diversions will reduce Platte River flows immediately below the diversion weir by only 5 percent, assuming the MBPP replace­ ment water is put into the river at the project. This flow reduction would have only a minimal impact on fish populations in the area. If the MBPP replacement water is not put into the Platte at the project, but rather is replaced at the state line, flow reductions just below the weir would average 7.5 percent for the average flow year. During wet years the percent flow reductions would be around 2 to 3 percent and during dry years the reductions are estimated to be between 5 and 9 percent (Table 12). The maximum flow reductions (in terms of percent reduction in flow) due to CCIO would occur during extremely dry years such as 1953 (Table 12). During the winter and early spring months of a dry year similar to 1953, monthly depletions are estimated to run around 24 to 29 percent of the North Platte River flows. These flow reduc­ tions might be expected to impact fish production and move­ ment within the area immediately downstream of the project.

Table 13 presents estimated depletions at the Wyoming-Nebraska state line, and even during the lowest flow months of an extremely dry year (such as 1953) the percent flow reductions never exceed 8 percent. Flow reductions at the state line

IV-26 during an average flow year are estimated at 3.8 and 3.6 percent (of annual flows), depending upon where the MBPP replacement water enters the river. The CCID depletions are predicted to change the average water level at the state line by less than 0.02 feet (REA, 1980).

Winter releases from Glendo Reservoir have been suggested as a mitigation action by the Wyoming Game and Fish Department because increased flows in the North Platte River between Glendo an Guernsey reservoirs during the late fall and winter would be very beneficial to the trout fishery in that section of the river. The CCID would be willing to evaluate the possibility of using winter releases, but existing legal and physical constraints to winter releases must first be removed or modified by the responsible state and federal agencies. The Bureau of Reclamation is required to operate Glendo Darn and Reservoir in accordance with the 1952 Glendo Unit Definite Plan Report and the 1953 Stipulation of the North Platte River Supreme Court Decree of 1945. This places limitations on water releases from Glendo Reservoir with respect to water use and release schedules, and precludes winter releases from Glendo. In addition to these legal constraints, the design of the outlet works at both Glendo and Guernsey Dams prevent limited water releases of the magnitude suggested by Wyoming Game and Fish. For example, the minimum release by the Glendo power plant is 600 cfs. Therefore, before winter releases could occur the outlet works would have to be modi­ fied. The Wyoming Game and Fish Department has requested appropriate Federal and State agencies to investigate the feasibility of winter releases, and a joint committee has been formed to initiate studies. If the legal and physical constraints to winter releases could be changed, and if release schedules mutually acceptable to the state, the Bureau, and the irrigators could be worked out, then miti­ gating winter releases could be considered. Under a winter release scenario, the Corn Creek project would divert water from the North Platte River after the irrigation season, store that water in Teeters Reservoir over the winter, and use it to irrigate crops during the following season.

Grayrocks Reservoir and the Laramie River. Grayrocks Reser­ voir, with a capacity of 104,000 ac-ft, was built primarily as a cooling-water supply for the Laramie River Generating Station (the MBPP) and as a water resource for the CCID. The reservoir currently supports sport fish such as walleye, yellow perch, channel catfish, bass, and crappie. The walleye populations in this relatively new reservoir are becoming established, along with good prey populations of yellow perch and gizzard shad, and the recreational fishing at the lake is continuing to improve.

The withdrawal of water for Corn Creek could have a minor impact on reservoir levels and may have a minor impact on

IV-27 the reservoir as a recreational area. However, required minimum releases from Grayrocks Reservoir are adequate to satisfy the proposed ccrD water withdrawals. Therefore, the development of the project will result in only minor changes in existing releases from Grayrocks and resultant Laramie River flows. The MBPP is required by the u.s. District Court Agreement to limit maximum consumption by the Laramie River Generating Station to 23,250 ac-ft, and also to make the following minimum releases from the reservoir:

April: 50 cfs delivered at the mouth of the Laramie River

May-September: 40 cfs, or 75 percent of the natural flow of the Laramie River at its mouth, whichever is greater

October-March: 40 cfs delivered at the mouth of the Laramie River

These minimum releases can be modified only if the total reservoir storage drops below 50,000 ac-ft and MBPP water rights at three other sources are unable to supply the re­ quired water. Therefore, the development of cerD would nega­ tively influence Grayrocks.Reservoir and the Laramie River only during an extended drought.

The development of Corn Creek would have no negative impact on the fishery in the Laramie River, but may be beneficial because required water releases from Grayrocks would not be diverted from the Laramie until it reaches the Laramie River-North Platte River confluence. The entire flow from Grayrocks would be available in the river to support sport fish. The Wyoming Game and Fish Department would like to develop a smallmouth bass-channel catfish fishery in the Laramie River below Grayrocks Reservoir. This would be a good addition to the area where warm-water sport fishing areas are very limited.

Teeters Reservoir. The construction of Teeters Reservoir as an onsite storage reservoir for the Corn Creek Project would create a new 800 acre lake. The water levels within the reservoir would fluctuate considerably during the irrigation season, and would rise gradually during the winter. The reservoir would be full in the spring and provide good habi­ tat for spring migrating waterfowl. Because of the wide fluctuations in water levels and volume that this reservoir will be subjected to, no plans are considered at this time for a fishery in the lake. However, the District has acquired an option on property that could provide public access to the reservoir, and may consider developing a sport fishery in the reservoir. If state and federal funds are used to help finance the development of the project, then ceID will

IV-28 commit to evaluating the feasibility of designing a minimum storage pool for Teeters Reservoir. If this future engineer­ ing study indicates a minimum pool is feasible, then the District would work with the Wyoming Game and Fish Department and the USFWS to try to develop a sport fishery in the reser­ voir. Public access would be provided to the reservoir, and to other lands that may be specifically set aside as wildlife management areas.

3. SOCIOECONOMIC COY~ONENTS

Population and Employment

The work force for construction of the Corn Creek Irrigation Project would not be large (from a few people up to 10 or 20 during peak periods), and those workers coming into the area would not be in the area for any extended period. The con­ struction supervisors and highly skilled people would come into the area because they would be employed by the firms awarded the construction contracts, but much of the remaining work force could be hired locally. Construction of Teeters Dam, the buried pipeline, and the North Platte diversion weir would take about 18 months.

No relocation of any residences would be required, and after the project is constructed, the area's population and employ­ ment structure would be the same as prior to construction of the irrigation project.

The increase in crop production and diversity, and the more consistent production from year to year that would result from the development of CCID lands would add substantially to the economic base in the county. The CCID would place about 15,000 acres under irrigation, adding about 10 percent to the acreage currently under irrigation in the county. Land tax valuations would also increase significantly because conversion of rangeland to Class'II irrigated land would increase the tax value by nearly six fold.

Land Use

Approximately 800 acres of land would be used for the Teeters Reservoir. The reservoir site is presently pastureland.

The present land use within the District is approximately 40-percent dry cropland and GO-percent rangeland. The assumed irrigated land use after the proposed irrigation development is completed would be:

Small grains 10 percent Dry beans IG percent Sugar beets 12 percent Corn 21 percent Alfalfa 41 percent

IV-29 Assuming 15,000 irrigated acres would be served by the District, approximately 6,000 acres of dry cropland and 9,000 acres of rangeland will be converted to irrigated cropland.

Recreation, Area History, and Cultural Resources

If property owners within the ccrD allow public access to their lands and work with the Wyoming Game and Fish Depart­ ment, the development of the irrigation project could provide new recreational opportunities. Proper development of shelter belts and small game and game bird cover along irrigated fields could improve hunting opportunities in the area. Also Teeters Reservoir would provide a waterfowl resting and feeding area and could be used by area bird watchers.

The Fort Laramie National Historic Site is located along the north shore of the Laramie River just upstream of its confluence with the North Platte River. The Corn Creek Project facilities at the confluence of the rivers could be visible to visitors at the historic site. Although the current entrance and layout of the historic site, operated by the National Park Service (NPS), keeps most visitors away from the river, the NPS has plans to redesign the park entrance at some time in the future. The conceptual design would route visitors along the river and a picnic area and nature trail would be developed near the confluence of the two rivers.

The river pumping station for the Corn Creek Project would be designed to blend into the natural setting as much as possible or be build underground. Likewise, the flood protection levee would be landscaped appropriately with nat­ ural ground cover to reduce potential visual impacts and shrubs and cottonwoods would be planted in areas adjacent to the diversion pool. The major impact to the historic site visitors would be the diversion weir on the North Platte River. The ccrn will work with the NPS to reduce the unnat­ ural visual aspects of the weir. Appropriate noise insulation techniques will be used at the pumping station to reduce noise impacts.

The potential for cultural or historic resources occurring on the farmland planned for irrigation is low. These lands are far from the river valleys and removed from known historic trails and stage-coach lines in the area. The CCln will work with the Wyoming State Historic Preservation Officer to conduct required cultural resource surveys prior to develop­ ment of the farmland and protect new finds.

The possibility of encountering cultural or historic resources during- construction of the North Platte diversion weir and river pumping station is relatively high. One primary concern is Fort Williams. The original location of the Fort, the

IV-30 first settlement in the area, is currently unknown. However, some historians think it was located near the confluence of the Laramie and North Platte rivers. Other historians think it may be buried at or near the present Fort Laramie Historic Site. Since the confluence of the Laramie and North Platte rivers has shifted several times in recent history the present­ day confluence could be removed from unknown historic sites.

A cultural resource survey would be conducted in the area of the proposed diversion weir and pumping station prior to any construction in the area. Also, care would be taken during all excavation operations, and procedures recommended by the State Historic Preservation Officer to report and protect new finds would be followed.

B. TEETERS RESERVOIR WITH INFILTRATION GALLERY

The second project alternative would differ from the first only in the way water is withdrawn from the Laramie and North Platte rivers. Instead of a diversion weir across the North Platte River an infiltration gallery would be installed in the Laramie River bed near the confluence (Figure 3). This second alternative would include the onsite storage reservoir on Cherry Creek, the buried pipeline and water distribution system, and pumping stations at the Laramie River and at Teeters Reservoir; essentially the same as the first project alternative.

The environmental consequences of the two alternatives, there­ fore, differ only with respect to the expected impacts of the two different water withdrawal facilities. The infiltra­ tion gallery would have two major advantages over the diversion weir with respect to environmental impacts. First, the infil­ tration gallery would be buried within the river bed so after construction was completed there would be no physical obstruc­ tion to river flows and fish movement. Upstream and downstream fish movement would be unobstructed even during low water periods, unless the vertical currents down into the river bed (i.e., into the gallery) affect fish behavior. Second, the infiltration gallery would be invisible, and no diversion pool would be required. Therefore, the concerns of a visible impact to the historic scene at the Fort Laramie National Historic Site would be reduced considerably. A river pumping station would still be required, but that facility would be visibly blended into the natural setting (for both alternatives).

The construction of the infiltration gallery would require dredging a larger area of the river bed than the diversion weir alternative, and would therefore produce more impacts during construction. However, these impacts would be temporary and confined primarily to physical disturbance of the river bed and increased turbidity. The construction of the gallery

IV-31 would be done under the requirements of appropriate state water quality and federal dredge and fill permits.

Additional studies will be required, including field testing, to determine if a gallery is technically feasible for this project. Operational problems are expected from silt and possibly algae growth reducing flowrates through the gravel river bed, and the potential magnitude of that problem will require further studies. c. NO-ACTION ALTERNATIVE The no-action alternative consists of CCID members continuing to operate their ranches without irrigated acreage. The land use would remain essentially the same and most of the area would remain as rangeland. Cropland would remain under dryland farming and consist primarily of winter wheat. Crop yields would be dependent upon precipitation patterns in any particular year.

The benefits that would accrue if the project were to proceed will not occur under the no-action alternative. The projected increase in goods and services resulting from an intensified agricultural production would not materialize. Monetary gains to Goshen County and the City of Torrington as a result of the short-term construction activities and the long-term increases in crop production will not occur. The assessed value of the land for taxes would not increase, an impact to the county of about $50,000 per year in projected tax increases.

Glendo Reservoir storage includes 40,000 ac-ft per year that has been allocated for irrigation use in Wyoming and Nebraska, and 15,000 ac-ft of that water must be used for irrigation in Wyoming below Guernsey Reservoir. Wyoming is aggressively pursuing water development opportunities in the North Platte basin to utilize that water allocated to Wyoming by the North Platte Decree, and the Corn Creek project represents one of the few feasible projects that could use North Platte water before it flows into Nebraska. Therefore, if allocated irri­ gation water is not used by CCID the water could remain unused or flow downriver into Nebraska.

Finally, the positive and negative impacts that would have resulted from the two development alternatives (alternatives A and B) would not occur under the no-action alternative.

DE/27R/032

IV-32 Consultation and Coordination V. CONSULTATION AND COORDINATION

CH2M HILL was retained by the WWDC in November 1982 to study the engineering and economic feasibility of developing about 15,000 acres of irrigated cropland for the CCID. The District subsequently requested CH2M HILL to prepare an environmental assessment of the project. The Wyoming Game and Fish Depart­ ment was requested by WWDC to assist in the feasibility and environmental studies and has prepared two reports on the project (Wyoming Game and Fish Department, 1983 and 1984). These reports provided baseline data to the project, presented the department1s concerns related to impacts on terrestrial and aquatic ecosystems, and suggested mitigation actions.

In early 1983, a preliminary Interim Report for the project was issued to present the results of the engineering feasi­ bility studies. At that time the ~~C solicited formal com­ ments from agencies concerning the project. Prior to that time, the project staff and WWDC had contacted and met with the Wyoming Game and Fish Department, the u.s. Bureau of Reclamation, the National Park Service, and the u.s. Fish and Wildlife Service.

The Wyoming Game and Fish Department conducted biological field studies for the project during 1983 and has prepared reports addressing current conditions, potential impacts, and proposed mitigation actions. The National Park Service was consulted regarding potential impacts on the Fort Laramie National Historic Site, and numerous agencies were asked to comment on the Interim Report. More recently, the u.s. Bureau of Reclamation and the U.S. Fish and Wildlife Service (USFWS) have initiated the endangered species (Section 7c) review process at the request of the project staff. A meeting was held in December 1984 to discuss the project environmental impacts and potential for impacting threatened or endangered animals. Representatives of the District, USBR, and USFWS attended the December meeting, and the USBR and USFWS have continued to consult with the project staff and the District.

In May 1985, a Draft Environmental Assessment (EA) for the Corn Creek Irrigation Project was submitted for agency review. The District mailed the Draft EA directly to the USBR, USFWS, National Park Service, National Wildlife Federation, u.s. Army Corps of Engineers, Platte River Whooping Crane Habitat Main­ tenance Trust, and Wyoming Office of State Planning and Coord­ ination. Dick Hartman, Wyoming State Planning Coordinator, accepted the responsibility for coordinating the Wyoming state agency reviews and sent the Draft EA to 8 to 10 state agency offices. The District, subsequently, received written comments on the Draft EA from the USBR, USFWS, National Park Service, and seven Wyoming agency offices. Copies of these comment letters are included in Appendix C of this Final EA. All written comments from the agencies were considered during the preparation of the Final EA.

V-1 The coordinating agencies at this point in time include:

o Federal Agencies u.s. Bureau of Reclamation U.S. Fish and Wildlife Service U.S. Army Corps of Engineers National Park Service

o State Agencies

Wyoming State Planning and Coordination Office

Wyoming Water Development Commission

Wyoming Game and Fish Department

Wyoming State Engineers Office

Wyoming Recreation Commission

Wyoming State Archives, Museums and Historical Department

Wyoming Department of Environmental Quality

o Others

Platte River Whooping Crane Habitat Maintenance Trust

National Wildlife Federation

DE23R/061

V-2 LITERATURE CITED

Central Nebraska Public Power and Irrigation District (CNPPID). 1982. Environmental Assessment for the Proposed Purchase of Storage Water From the Glendo Reservoir. Report submitted by CNPPID to USDI, Bureau of Reclamation, Denver, Colorado. February 1982.

CH2M HILL. 1983. Interim Report for the Corn Creek Irriga­ tion Project. Report submitted to the Wyoming Water Development Commission, Cheyenne, Wyoming. May 1983.

High Plains Underground Water Conservation District. 1981. The Cross Section, No. 1 May, June, 1981.

Hurlbut, Kersich, and McCullough. 1975. Corn Creek Sprinkler Irrigation Project, Loan Application Report. Revised in December 1975.

Olendorff, R.R., A.D. Miller, and R.N. Lehman. 1981. Suggested Practices for Raptor Protection on Power Lines, The State of the Art in 1981.

Rural Electrification Administration (REA). 1976. Final Environmental Impact Statement, Missouri Basin Power Project. USDA-REA-EIS (ADM) 76-2-F. Report prepared for the U.S. Department of Agriculture, REA, by Basin Electric Power Cooperative and REA. May 1976.

Rural Electrification Administration (REA). 1980. Final Supplemental Environmental Impact Statement, Missouri Basin Power Project. USDA-REA (ADM) 76-2-FS. Report prepared for the U.S. Department of Agriculture, REA, by Dames and Moore under the joint direction of the REA and Army Corps of Engineers.

Rural Electrification Administration (REA). 1980. Appendix to Final Supplemental Environmental Impact Statement, Missouri Basin Power Project. USDA-REA (ADM) 76-2-DSA. Report prepared for the u.S. Department of Agriculture, REA by Dames and Moore under the joint direction of the REA, and Army Corps of Engineers.

Soil Conservation Service (SCS). 1971. Soil Survey of Goshen County, Wyoming, Southern Part. U.S. Department of Agriculture, Soil Conservation Service in cooperation with the Wyoming Agricultural Experiment Station.

Soil Conservation Service. 1979. Corn Creek Watershed Pre­ liminary Investigation Report. U.S. Department of Agriculture, Soil Conservation Service. December 1979. u.s. Fish and Wildlife Service. 1981. The Platte River Ecology Study, Special Research Report. U.S. Fish and Wildlife Service, Northern Prairie Wildlife Research Center, Jamestown, North Dakota. June 1981. u.s. Fish and Wildlife Service. 1984. Letter from Endan­ gered Species Field Supervisor to the Bureau of Recla­ mation's Lower Missouri Region, Regional Office in Denver, Colorado. u.S. Geological Survey. 1980. Water Resources Data for Wyoming, Water Year 1980. Volume 1. Missouri River Basin. u.S. Geological Survey Water-Data Report WY-80-1. u.S. Geological Survey. 1981. Water Resources Data for Wyoming, Water Year 1981. Volume 1, Missouri River Basin. u.S. Geological Survey Water-Data Report, WY-81-1.

u.s. Geological Survey. 1982. Water Resources Data­ Wyoming. Water Year 1982. U.S. Geological Survey Water-Data Report, WY-82-1.

Water and Power Resources Service. 1980. Point Flow Study, North Platte River, 1941-1977. Water and Power Resources Service, Lower Missouri Region, July 1980.

Wyoming Division of Research and Statistics. 1979. Wyoming Population and Employment Forecast Report. Wyoming Division of Research and Statistics, Department of Administration and Fiscal Control, Revised July 1979.

Wyoming Game and Fish Department. 1983. Level III Report on Potential Fishery Impacts, Corn Creek Irrigation Project. Report submitted to Wyoming Water Development Commission, December 1983.

Wyoming Game and Fish Department. 1984. Level III Terres­ trial Wildlife Impact Report (Interim). Corn Creek Irrigation District Water Development Project. Report submitted to Wyoming Water Development Commission, Jan­ uary 1984.

Wyoming Game and Fish Department. 1985. Modified Creel Census for Grayrocks Reservoir. Management Area No. 50 Report, Laramie.

Wyoming Recreation Commission. 1980. 1980 Wyoming State Comprehensive Outdoor Recreation Plan. Report prepared by Wyoming Recreation Corr~ission and Oblinger-McCaleb Architects, Engineers, and Planners. Wyoming Recreation Commission. 1981. 1980 State Comprehen­ sive Outdoor Recreation Plan (SCORP) Summary.

Wyoming State Engineers Office. 1971. Water and Related Land Resources of the Platte River Basin, the Wyoming Water Planning Program, Report No.9, September 1971.

DE23R/062 APPENDIX A

BIRD AND MAMMAL SPECIES LISTS TABLE A-1

LIST OF AVIAN SPECIES POTENTIALLY PRESENT ON CORN CREEK PROJECT LANDS

UPLAND GAME BIRDS NONGAME BIRDS

Sora Horned grebe American coot* Eared grebe Conunon snipe Western grebe* Sandhill crane Pied-billed grebe* Sharp-tailed grouse White pelican* Bobwhite quail Double-crested cormorant* Ring-necked pheasant* Great blue heron Gray partridge Green heron Mourning dove* Snowy egret Turkey Black-crowned night heron American bittern* White-faced ibis Turkey vulture Sharp-shinned hawk Cooper's hawk WATERFOWL Red-tailed hawk* Swainson's hawk* Canada goose* Rough-legged hawk* Snow goose* Ferruginous hawk* Mallard* Golden eagle* Gadwall Bald eagle* Pintail Marsh hawk* Green-winged teal Osprey Blue-winged teal Prairie falcon* Cinnamon teal* Merlin American wigeon American kestrel* Northern shoveler* American avocet* Wood duck Semi-palmated plover* Redhead Killdeer* Ring-necked duck Piping plover Canvasback Mountain plover Greater scaup Black-bellied plover Lesser scaup Marbled godwit Common goldeneye Long-billed curlew Bufflehead Upland sandpiper Ruddy duck Greater yellowlegs Conunon merganser Lesser yellowlegs Red-breasted merganser Solitary sandpiper Virginia rail willet Spotted sandpiper Wilson's phalarope Northern phalarope Long-billed dowitcher Semipalmated sandpiper * Species observed on Western sandpiper the project site by Least sandpiper Wyoming Game and Fish White-rumped sandpiper Department (1984) Baird's sandpiper TABLE A-I (CONT'D)

NONGAME BIRDS NONGAME BIRDS NONGAME BIRDS

Pectoral sandpiper Black-billed magpie* Lazuli bunting Stilt sandpiper Common crow Common redpoll Dunlin Pinon jay Pine siskin Herring gull Black-capped chickadee American goldfinch California gull* Mountain chickadee Rufous-sided towhee* Ring-billed gull White-breasted nuthatch Lark bunting* Franklin's gull Red-breasted nuthatch Savannah sparrow Bonaparte's gull* House wren* Grasshopper sparrow Forster's tern Long-billed marsh wren Vesper sparrow* Caspian tern Canon wren Lark sparrow* Rock dove Rock wren* Tree sparrow Yellow-billed cuckoo Mockingbird Chipping sparrow Black-billed cuckoo Brown thrasher Clay-colored sparrow Screech owl Sage thrasher Brewer's sparrow Barn owl American robin Field sparrow Great horned owl Swainson's thrush Harris' sparrow Burrowing owl* Veery Lincoln's sparrow Long-eared owl* Eastern bluebird Song sparrow Short-eared owl Mountain bluebird McCown's longspur Saw-whet owl Townsend's solitaire Lapland longspur Poorwill Bohemian waxwing Chestnut-collared Common nighthawk* Cedar waxwing longspur Chimney swift­ Northern shrike Snow bunting White-throated swift Loggerhead shrike* Broad-tailed hummingbird Starling Belted kingfisher* Solitary vireo Common flicker* Yellow warbler* Red-headed woodpecker* Yellow-rumped warbler Lewis' woodpecker Blackpoll Yellow-bellied sapsucker Palm warbler Hairy woodpecker* Ovenbird Downy woodpecker Northern waterthrush Eastern kingbird* MacGillivray's warbler western kingbird* Common yellowthroat* Cassin's kingbird Yellow-breasted chat Eastern phoebe American redstart Say's phoebe House sparrow Least flycatcher Western meadowlark* Western wood pewee* Yellow-headed blackbird* Horned lark* Red-winged blackbird* Violet-green swallow* Orchard oriole Tree swallow Northern oriole* Bank swallow Rusty blackbird Rough-winged swallow Brewer's blackbird* Barn swallow* Common grackle Cliff swallow Brown-headed cowbird Purple martin Black-headed grosbeak* Blue jay Blue grosbeak DE/29R/22 TABLE A-2

LIST OF MAMMAL SPECIES POTENTIALLY PRESENT ON CORN CREEK PROJECT LANDS

FURBEARERS NONGAME MAMMALS

Beaver Masked shrew Muskrat Water shrew Long-tailed weasel Eastern mole Mink Small-footed myotis Badger Townsend's big-eared bat Bobcat* Big brown bat White-tailed jackrabbit Black-tailed jackrabbit* BIG GAME Yellow-bellied marmot Least chipmunk Mule deer* Spotted ground squirrel White-tailed deer* Thirteen-lined ground squirrel Pronghorn antelope* Black-tailed prairie dog Northern pocket gopher Plains pocket gopher Olive-backed pocket mouse SMALL GAME Plains pocket mouse Silky pocket mouse Eastern cottontail Ord's kangaroo rat* Desert cottontail* Plains harvest mouse Nuttal's cottontail Western harvest mouse Fox squirrel Deer mouse* Northern grasshopper mouse* Bushy-tailed woodrat Prairie vole Coyote* Red fox Swift fox Raccoon Black-footed ferret Striped skunk Opossum Porcupine Spotted skunk Sagebrush vole

* Species observed on the project site by Wyoming Game and Fish Department (1984).

DE/29R/22 Appendix B HYDROLOGY DATA NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,2510 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT UNITS a b a iJ RECORDED WHALEN RECORDED FT. LARAt1IE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1941 JAN. 0.90 0.90 2.60 1.93 FEF.• 0.40 121.40 2.00 1. 33 !"IAR. 0.70 0.70 2.40 .L • 73

APR. 2.40 2.40 5.30 .~ . 97 MAY. 69. 10 69. 10 78.50 76. 12 JUNE 58.40 58.40 63.6eJ 61.22 JULY 63.5eJ 63.50 66.90 64.52 -,., i.!t.-:, AUG. 69.90 69.90 73.40 ( L • 'Li ... SEPT. 26.00 26.00 31.5eJ 29. 1 :~~ OCT. 1.50 1. 5121 5.00 4.33 .-, NOV'. ..::.. 10 2.10 4.50 3.83 DEC. 8.80 8.80 10.90 10.23 TOTAL 303.71Zl 303.70 346.60 329" 4kl

1942 .JAN. 1.3121 1.30 4.2(2) 3.38

FEB. 1.00 1.0121 2.80 1 II 9~3 MAR. 1.10 1.10 2.80 1.98 APR. t6.60 16.60 ·24. 70 23.05 MAY 177.6121 177.60 221.20 218.26 .JUNE 25.40 25.4121 41.60 38.66 JULY 87.40 87.40 92.80 89.86 7, AUG. 7121.20 70.20 76.10 , ...J. 16 SEPT. 24.30 24.30 31.40 28.46 OCT. 1. 6eJ 1. 60 5.90 5.0:3 NOV. 5.70 5.70 9.40 ~=:.5a DEC. 7.20 7.20 11.20 i 0. 3fJ TOTAL 419.40 419.40 524.00 502.70

1943 .JAN. 7.90 7.90 11.50 110.74 FEE.. 3.30 3.3121 5.60 4.84 t"lAR. 4.80 4.80 15.20 14.44 -:-:r r:::;o APR. 12.50 12.50 39.10 •..1/ . -"-' MAY 3.80 3.80 55.70 52.99 .JUNE 4. eHZ) 4.1210 58.30 55. ::8 JULY 87. 10 87.1121 92.90 90. 19 AUG. 73.10 73.10 78.00 75.29 SEPT. 21.60 21.60 27. 10 24.39 OCT 1.70 1. 70 5.41;0 4.64 NOV. 0.50 0.50 3.50 ..;... 74 DEC. 0.50 0.50 2.60 :. 84 TOTAL 279. :50 279. ::~tz) 394.60 375. 0~j a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Wa.tel" .and Pmuer Rest::>urces Service, .July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gra~ Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,2~j~ AC-FT REPLACEMENT WATER AT r-ORT LARAMIE)

1000 AC-FT UN:TS a. b b RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW P..ELOW ADJUSTED FLOW AT AD.JUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1944 JAN 0.40 0.40 2.40 1.77 FEB. 0.10 0.10 2 .•20 1. 57 MAR. 0.40 0.40 2.20 1.57 APR. 0.90 0.90 3.80 MAY. 54.90 54.90 60.60 58.36 .JUNE 50.90 50.90 56.50 54.26 .JULY 80.10 ::-30. 10 82. ~ij0 79 7/:71 AUG. 73.90 73.90 76.00 SEPT. 25.00 25.00 30.60 28.36 OCT. i2l.80 0.80 4.60 3.97 NOV. 0.60 0.60 3.S(£j 2.87 DEC. 1Zl.50 0.50 2.80 2. 17 TOTAL 288.50 288.50 326.70 311Z.5~j

1945 .JAN. 0.40 0.40 4.20 3.43 FEB. 0.30 0.30 2.80 2.i2l3 MAR. 4.80 4.80 2.80 2.03 APR. 1.70 1.70 24."70 23.16 MAY 69.50 69.50 221.20 218.45 .JUNE 40.60 40.60 41.60 38.85 JULY 70.60 70.60 92.80 90.05 AUG. 59.40 59.40 76.10 73.35 :::;)'-,'"'COT ,. 47.10 47.10 31.40 OCT. 1.50 1.S0 5.90 5.13 NO\,/. ..,j.10 3. 10 9.40 DEC. 3. ·,0 3.70 11.20 10.43 TOTAL 302.70 302.70 400.40 380.50

1946 JAN. 2.10 2. 10 4.50 3.98 FEE.. 3. 10 3.10 4.80 4.28 MAR. 4.20 4.20 6.00 5.48 APR. 1.80 1.80 3. 10 MAY 32.60 32.60 37.30 35.45 ·JUNE 45.50 45.51Zl 47.80 45.95 .JULY 60.90 60.90 64.00 1~2. 15 AUG. 58.20 58.20 62.01() 60.15 SEPT. 8.80 8.80 16.80 14.QS OCT 2.30 2.30 12.50 11. '71 8 NO\,I. 1.20 1.20 7.40 ,S.88

-: O~ 7 '",,::Q 0.90 0.90 '-/. UY,.,/ '-1. ~'-J TOT(-\L 2·;';: 1.. 6ft) .~:~~~ 1 • 6v~ ;~J~9. 8l~

a Source: Point Flow Study, North Platte River, Wyoming - Nebras~a, Water and PQllJer Resources Service, July 19;](0. b Flow adjustments were made using simulated depletions from Banner and Associates Gra~ Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT UNITS e. b e. b RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS r l. LARAMIE FLOWS

1947 JAN. 0.40 0.40 2.7121 2.03 FEB. 0.50 0.50 2.3121 1. 63 t"lAR. 121.90 121.90 5.3121 4. 6~3 APR. 1. 00 1. 00 5.20 3.87 MAY. 23.3121 23.30 35.4121 33.02 JUNE 61.60 61.60 108.60 11D6.22 .JULY 39.4121 39.40 66.3121 63.92 AUG. 61.70 61.70 71.50 69.12 !:"3EPT. 22.50 22.5121 31.20 28.82 OCT. 2.10 2. 10 9.80 9. 13 NOV. 0.30 0.30 3.30 2. 6~3 DEC. 0.30 0.30 5.00 4.33 TOTAL 214.00 214.00 346.70 329. 5~7J

1948 JAN. 1. 40 1.40 7.30 6.70 FEB. 1. 70 1. 70 6.40 5.80 MAR. 26.5121 26.50 3121.70 30.10 APR. 1.70 1.70 9.0121 7.79 MAY 25. 10 25.1(2) 32.4121 3121.25 JUNE 31.7121 31.7121 46.8121 44.65 .]IJLY 62.40 62.40 69. 10 66.95 AUG. tll2l.10 60. 10 67.60 65.4S SEPT. 18.20 18.20 25.80 23s65 OCT. 2.70 2.7121 9.70 9. 10 NOV. 1. 6 ill 1.60 5.6121 5.00 DEC. 0.4121 0.4121 3.7~ 3. 10 TOTAL 233.50 233.50 314.30 298.70

1949 0.30 0.30 4.00 3.3!:-3

• o,~ FEB. 0.30 0.30 4.50 '-1. ,-! .,.,....! MAR. 1. 60 1.60 4.17.!0 ..'..J • •_rl.J APR. 2. 10 2.10 4.30 3.07 MAY 7.30 7.312l 15. 10 12. 9~~ ,JUNE 20.8121 20.80 b3.20 61.00 ,JULY 79. 1+0 79.40 87.h0 8S.4V: AUG. 7eJ.90 70.90 77.20 75.00

'-:l'i SEPT. 16.60 16.612l 23.30 .a:...:. tI lIZ OCT 3.20 3.20 12.80 12.18 NOV. 4.90 4.90 12.40 11. 78 DEC. 7.70 7.70 11. 1 ~ 10.48 TOTAL 215.10 215.10 319. ,-710 303. 70 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980.

b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11~2S0 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

10~0 Al:-FT UNITS a b a b RECORDED WHALEN RECORDED FT . LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJI...'STEn WHALEN FLOWS FT . LARAMIE FLOWS

1950 JAN. 5.90 5.90 9.30 8. 7~~3 ' -"7 FEB. 2.50 2.50 4.90 ,+ • ..;j-..J MAR. 5.20 5.20 7. ~50 6.93 --:. .-. 1"""! APR. ..:... 10 2. 1~ 3.30 ...;.. . .. I r1AY. 21.00 21.00 26.SQ) 24.48 JUNE 61.30 61.30 67.213 65. lE: ~JULY 62.60 62.60 69.90 67.88 AUG. 57.90 57.90 61.50 59.48 SEPT. 17.20 17.20 24.80 22.78 OCT. 2.71£1 2.70 9.70 9 13 NOV. 1.40 1. 40 5.00 4. 43 DEC. 0.40 0.40 3.50 2.93 TOTAL 240.20 240.20 293.20 278.60 .-. 1951 JAN. 0.30 I~. 30 2.60 ~. 10 FEB. 121.20 121.20 2.3121 1. 80 MAR. 0.20 0.20 2.20 1. 70 ' -.,... APR. 0.70 0.70 2.30 1 •.~I;:i MAY 19.31Zl 19.30 26.60 24.82 .JUNE 22.50 22.50 30.80 29.02 JULY 61.40 61.40 68.60 66.82 "j'"-:, AlJG. 55.90 '35.90 65. 10 O·.j • '...J .... .-:. 1 "7(')\ SEPT. 14.90 14.90 4..1.a--.l"ti.J lS'~ 52 OCT. 16.60 16.60 26. ~50 2b.0CfJ NOt./. 4.00 4.00 7.70 7.20 DEC. 0. 10 0. 10 ..:;. 10 2.60 TOTAL 196. 10 196. 10 259.31£1 246.40

1952 JAN. 0. l0 0. 10 2.80 1.9:3 FEB. 0. 10 0. 10 2.3~ 1. ~8 MAR. 0.90 0.90 2.90 2.0l3 APR. 18. 10 18. 10 34. 10 32.45 l"iAY 85.40 85.40 1~3.20 1.00.26 JUNE 157.40 157.40 177.20 174. '26 .JULY 74.20 74.:20 78.:20 75. 2l~ AUG. 72. 10 72. 10 75.60 72.6.-S if SEPT. 36.~0 36.('J~ 40.70 ,_I i 76 1 c:. OCT 6.50 6.50 16.130 J..-i_ 18 NOV. 6.50 6.50 16. 10 15.28 DEC. 2.00 2.00 8.60 7.78

TOTi\L .~:s 9 r. 30 '~~S9. 30 557. l~~~ :S3.~" :~ (?)

a Source: Point ~lOW Study, North Platte River, Wyoming - Nebraska, L.Ja.ter and POI!Jer Resol_trees S,::rvice, July 1980. b Flow adjustments were made using simulated depletions fram ~anner and Associates Gray Racks Operati~n Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

100121 AC-FT UNITS a b ·a 1} --r RECORDED WHALEN RECORDED r I • LARAMIE YE(~R FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1953 JAN. 0.:20 0.20 3.80 3.31 FEB. 0. 10 0.10 3. 10 2.61 MAR. 0.70 fD.70 3.70 3.21

~ 0'7 APR. 1.00 1.00 6.80 ..J.'...J-..J MAY. 21.40 21.40 23.30 21.5,~ ,JUNE 39.90 39.90 40.20 38.46 .JULY 72.60 72.60 73.80 72.06 AUG. 44.40 44.40 48.60 46.86 SEPT. 30.20 30.20 32.70 30.96 OCT. 1.90 1.90 8.(2)0 7.51 NOV. 1.00 1.00 6.90 6.41

~ i",,1 DEC. 121.40 0.40 3.50 "-/. "-1.L TOTAL 213.80 213.80 ·254.l~0 241.40

.-, 1954 JAN. eJ.30 121.30 2.80 ..::.. . ~~.J. 1 ~ FEB .. 0.60 0.60 2.40 2. ~ J. MAR. 0 .. 50 0.50 2.50 2.21 APR. 0.20 0.20 2. 10 1. 52 MAY 6.40 6.40 6.80 5.76 JUNE 21.70 21.70 21.30 20.26 .JULY 54.20 54.20 52.80 51. 7,~ AUG. 31.50 31.50 33.50 32.4,S SEPT. 10 .. 30 10.30 11. 11'3 10.06 OCT. 1.60 1.60 5.70 5.4l NOv'. 0.70 0.70 5.90 S.,:Sl DEC. 0.50 0.50 2.7121 2.4t TOTAL 128.50 128.5121 150.00 142~ ~50

1955 ,JAN. 0.20 0.:20 2.60 2.27 FEP, " 121.20 0.20 2. 10 1. 77

MAR. 0. 10 0. l0 2.1Qi 1 a 7°7 APR. 0.60 0.60 2.50 1. 84 MAY 11.30 11.30 11.80 HL61 ,JIJNE 14.60 14.60 21.90 :::0.71 ,JUL Y 52.90 52.9(2) 56.00 54.81 AUG. 38.70 38.70 42.00 40.81 SEPT. 11.~0 11.00 14.00 121181 OCT 1.40 1.40 6. 10 5. 7? NOV. 0.90 0.9eJ 6.20 5.87 DEC. 1.50 1. 50 7.400 6.67 TOTAL 133.40 133.40 173.80 165c20

a Source: Paint Flow Stud~, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF~9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

11£100 AC-Fi UNITS a b a b RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW "BELOW AD.JUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1956 JAN. 1. 30 1. 30 6.50 5.96 FEB. 0.90 0.90 5.6(2) 5.06 MAR. 0.80 0.80 6.30 5.76 APR. 1. 30 1.3(2) 5.60 4. S3

'-I~ MAY. 30. 10 30. 10 29.90 "';':'l .98 JiJNE 45.7(2) 45.70 44.30 42.38 .JULY 67.70 67.70 66.90 64.98 AUG. 70.70 70.70 72.00 70.08 SEPT. 21.50 21. 50 23.50 21.58 OCT. 1. 2eJ 1.20 5.80 5.26 c; NOV. 0.80 0.80 6.30 ...i. 76 DEC. 0.70 0.70 6.4(2) 5.86 TOTAL 242.70 242.70 279. lID 265.210

1957 .JAN. 0.80 0.80 5.40 4.76 FEB. 0.90 0.90 5.40 4.76 MAR .. 0.6(2) 0.60 5.00 4.36 APR. 1. ~0 1.17.)0 5.80 4.5:2 MAY 33.40 33.40 53.30 51. 01 .JUNE 17.30 17.30 30.30 28.01 0-: .JUL.Y 84.30 84.310 85.40 ',J'-J • 11 Al)\:i. 73.80 73.80 79. 'l0 76.8~

SEPT. 23.90 23.90 31.50 2S: a '21

OCT. 1.90 1. 90 10.80 10. ,l.. I.J NOV .. 0.90 0.90 .i. 1 • 112) 10.46 DEC. 0.70 0.70 10.90 10.26 TOTAL 239.50 239.50 333.80 317.20

1958 JAN. 0.70 0.70 9.60 8.98 FEr. • 0.60 0.60 8. 10 7.48 c· 00 MAR. 0.70 0.70 9.60 1"'/. I'..J

APR .. 1. 0i2) 1.00 12.80 11 s Sr~ t1AY 28.0i2) 28.00 39.70 37.49 .JUNE 19.30 19.30 23.90 21. ,~9 .JULY 73.40 73.40 76.60 74a39 AUG. 81.20 81.20 83.20 80.99 SEPT. 26.30 26.3i2) 3(:;:.60 28.39 OCT 2.5eJ 2.50 9.90 9.28

! '-'0 NOV. 0.40 0.40 7.90 • ~I_: DEC. 0.90 0.90 9.50 8.88 TC)"fr,L :~~ :-:r'} • ~?J e; :,~35. 00 ~L~~ 1. /1-0 :~~05 . 4i1i

a Source: Point Flow Study, North Platte River, W~orning - Nebraska~ We.t~r a.nd ?ohJer Resources Service, .ju.ly 19;.10. b Flow adjustments were made using simulated depletions from Banner a.nd A'::;':50ciates (::ira.y RDck5 Operatir:m Study G"RGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,25121 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

10013 AC-FT UNITS <3. b a RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAt1IE FLOWS

1959 .JAN. 1.I7.)QI 1.17.10 9.9121 9. 3\~ FEB. QI.BQI e).8Q1 7.5121 6.90 MAR. QI.8121 Ql.8Q1 8.90 8.3t'.l APR. 1. 10 1. 10 10.6121 9.41 . ," ...,...... MAY. 9.10 9. 10 18.90 l b a l / .JUNE 30.60 30.6\2i 32.70 30.57 .JULY 86.20 86.2121 85.40 AUG. 71.9121 71.90 73.4121 71.27 SEPT. 31.8Q1 31.8121 34.9121 32.77 OCT. 2.30 2.30 10.90 10.30 NOv'. QI.3Q1 QI.30 8.50 7.90 DEC. 0.30 0.30 8.00 (.40 TOTAL 236.20 236.2Q1 309. ~)0 :294" 10

1960 ·JAN. 0.50 0.50 7. 10 6.53 FEB. 0.20 0.21Zl 6.7121 6. 13 MAR. 0.70 0.70 10.00 9.43 APR. 1.21Zl 1. :;:-~0 6.70 5.56 MAY 10.80 lQl.80 10.9Ql 8.86 JUNE 51.50 51.SQI 49.40 47.36 JULY 94. 1 QI 94.10 92.8Q1 90.76 , 0 -r' AUG. 7Q1.9Q1 70.9Q1 71.80 b /11 (f:j SEPT. 17.8121 17.80 18.60 16.56 OCT. eJ.9Q1 1Zl.90 4.30 3.73

~ i i.II NOV. 0.30 0.30 _' • .L '{..J 4.53 DEC. 0.9Q1 Ql.90 6.10 TOTAL 249.30 249.30 289.30 283.50

1961 JAN. 0.4Q1 0.40 5.3Q1 4.83 FEB. 0.30 0.30 4.80 4.33 MAR. 1.17.10 1. ill0 6.30 5.83 APR. 1. 80 1.80 6.90 5.96 r1AY 1.20 1.2Q1 6.00 4.33 .JUNE 16.60 16.60 23.30 21.63 JULY 93.2Q1 93.20 93.40 91.73 AUG. 53.10 53.10 53.70 SEPT. 24.60 24.60 25.60 23.9] OCT 1. 00 1. 00 5.60 5. 13 NO!,,,'. 0.10 0. "l12l 5.90

'!""'~,..,. J,.,tc- \_. eJ. 113 0.10 6.00 TOTAL t93.4\!j 193.40 :242.60 230.SC3 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resour~es Service, July 1980. b Flow adjustments were made using simulated depletions fram Banner and Associat@s Gray Rocks Operation'Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

10tZl!Zl AC-FT UNITS a b a b RECORDED WHALEN RECORDED FT. LAR.At"! I E: YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1962 JAN. ~.00 Q).Q)0 5.70 5.08 FEB. 0.30 0.30 7.7iD 7.08 MAR. 1.20 1.20 9.50 8.88 APR. 3.90 3.90 13.0(2) 1... 1.... 76 MAY. 43.60 43.60 49.20 46.99 ·JUNE 12.80 12.80 25.90 23.69 .JULY 60.80 60.80 68.30 66.09 AUG. 79.70 79.70 81.80 79.59 SEPT. 26.30 26.30 31.40 29. 19 OCT. 5.10 5.10 12.90 12.28 NOV. 1.70 1.70 8.813 8. 18 DEC. 0. 113 0. 10 7.50 6.88 TOTAL 235.50 235.50 321. -,~ 305.7tQ

1963 JAN. 2l.ilIQ'J 10.00 5.40 4.75 FEB. 0.60 0.60 8.30 7.65 MAR. 4.50 4.50 12.50 11.85 APR. 2.80 2.813 8.80 7. ::,0 MAY 55.30 55.30 54.50 5'-;' 18 JUNE 22.00 22.00 26.40 24.0>=; '"70 .JULY 98.20 98.20 98.10 95. ( '-/ AUG. 74.60 74.60 75.80 731148 SEPT. 21.30 21.310 28.10 25.78 OCT. 2.70 2.70 8.50 7. :=:5 NOI'; • 0.80 0.80 6.610 s. '7:5 4. ':""Ie: DEC. 0. 10 0.10 5.60 • II f ..J TOTAL 282.90 282.90 338.40 321. ,:S0

1964 ,JAN. 0. 10 0. 10 5.50 4.85 FEB. 0.00. 0.00 5.40 4.75 !"IAR. 0.'1.0 0. to 6.40 S. 7:-3 APR. 1. 10 1. 10 8.90 7.59 MAY 28.413 28.413 413.20 37.87 ·JUNE 39.20 39.210 45.60 43.27 JULY 97.70 97.70 97 . ~5eJ 95. 17 AUG. 80.20 80.20 81.0eJ 78.67 SEPT. 24.60 24.60 26. 1 ill '23~ 77 o ""7c:. OCT 5.00 5.00 9.Gj0 '-I .. '-1-1 NOV. 0.80 0.80 6.90 6.25 DEt:. 0.20 10.20 6.70 6.35

TOT;'\L 277.40 '277. i+0 338. !J0 .:-321 II 9f::' a Source: Point Flow Study, North Platte River, Wyoming - Nebraska. Water and Power Resources Service, Ju~y 1980. b ~low adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEt< PROJECT AT SELECTED SITES (WITH 11, 2S~ AC-FT REPLACEMENT WATER AT FORT LARAMIE)

11000 AC-FT UNITS a b a. \) RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW E.ELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FL(jWS

1 ri65 JAN. 0.20 0.20 5.90 5. (2)'--1 FEB. 0.40 12).40 5.80 4.99 MAR. 0.50 0.50 6.10 5. 2~' APR. 1.90 1.90 6.30 41168 MAY. 76.70 76.7~ 82.50 79.61 JUNE 91.90 91. 90 109.60 106.71 .JULY 64.70 64.70 68.40 ,!is.51 AUG. 76. 10 76.10 77.60 74.71 SEPT. 20.20 212i.20 25.7(0 22.81 OCT. 5.80 5.80 14.90 14.C09 NOV. 1.50 1. 5!Zl 9.40 8.59 DEC. 0.20 0.20 9.10 8.29 TOTAL 340. 10 340.10 421.10 400.20

1966 JAN. 0.20 0.20 8.20 7.55 FEB. 0.30 0.30 7.90 7.25 MAR. 1.50 1.50 10.60 9.95 APR. 19.20 19.20 256.70 255.39 MAY 56.70 56.70 55.50 53.17 -r...,. JUNE 40.60 40.60 40.10 37. { lJ .JULY 91.90 91.90 91.00 88.67 AUG. 57.30 57.30 58.20 55.87 SEPT. 21.30 21.30 24.20 21.87 OCT. 0.30 0.3!Zl 6.30 5.6:} NO\/. 0.00 0.00 5.80 5. 1 ~5 DEC. 0.00 0.00 6.60 5. 95 TOTAL 289.30 289.30 340.20 323.30

1967 JAN. eI. '''0 0.VJIl3 6.30 5. 6l~ FEB. 0.0121 0.0121 5.00 "+' • ."7'...J'+ MAR. 0. l0 0. H?J 5.40 4.7ii- APR. 2.10 2.10 5.30 3.99 ,"jAY l3.60 13.60 19.50 17. 1 ~.j .JUNE 48.80 48.810 72.90 70.55 JULY 65.30 65.30 78.50 lb. 1 :-s AUG. 81. 50 81.50 83.80 81. 45 SEPT. 29.40 29.40 32.30 29.95 OCT 4.80 4.80 10.40 9.74 NO\}. 3. 10 3.10 11.40 1~.74 T'I'- '"' UI=.I..J. 2.50 2.50 10.60 9.94 TOTAL 251.20 251.20 341.30 324.30

a Source: Point Flow Study, North Platte River, W~oming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Racks Operation Study GRGFflJ9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJ~CT AT SELECTED SITES (WITH 11,25~ AC-FT REPLACEMENT WATER AT FORT LARAMIE)

10~0 AC-FT UNITS a. b a b -T RECORDED WHALEN RECORDED t"" I. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED

,-, .-.,.~ WHALEN FLOWS FT. LARAMIE t"" .... uw-..J

1968 JAN. 3.00 3.00 12.40 11.58 .-:' FEB. ~. 10 2.1121 11.40 10.58 MAR. 10.80 10.80 18.50 17. ,!:,8 APR. 20.2121 20.2121 34.5121 32.85 t1AY. 27.50 27.50 4S.4~ 42.46 1 i.. .JUNE 8.20 8.20 11215. 10 1~2. J. '''/ .JULY 96.6121 96.60 97.30 94.36

AUG. 63.20 63.20 65. 10 '-1"':" • l '~I SEPT. 21.40 21.40 24.70 21. 76 OCT. 3.90 3.90 11. 10 10.28 NOV. 1.20 1.20 9.2el 8.38 DEC. 1.00 1.00 8.8~ 7.98 TOTAL 333.70 333.70 442.70 421.40

1969 JAN. 0.9121 0.9121 9.3121 8.58 FEE.• 1.0el 1.0el 8.Sel 7.78 MAR. 15.80 15.8\2'1 22.10 21.38 APR. 30.40 30.40 36.90 35.45 t1AY 35.30 35.30 35.40 32.8'2 .JUNE 23.30 23.30 26.00 23.42 .jULY 81.70 81.71l1 91.90 89.32 AUG. 05.90 85.90 86.7121 84. 1 :~~ SEPT. 29.20 29.20 310.20 27 .. 62

OCT. 6.30 T~" :30 13.20 12 It 4f: NOV. 0.9121 0.9121 8.50 7 78 DEC. 0. "t IZl 0. 10 7.20 6.4f3 TOTAL 31el.80 310.80 375.810 357. 1~

.. "70 197121 JAN. 1. 0121 1 • eJlZl 7.20 o • .-JI.J FEB. tzl.1Zl1ZI 0.tzl0 .~. 20 5.38 MAR. 0.1el 121. 10 6.9121 6.08 APR. 5.30 5.30 17. 10 15.45 t·1AY 39. :"50 39.50 62.90 59.96 JUNE 85. 10 85. 10 131.40 128.46 .JULY 84.3121 84.3121 96.8l?i 93.86 AUG. 73.4iZl 73.40 75.20 72. 2;~ SEPT. 21.90 21.90 24.80 21. 8,~ OCT 6.4121 6.40 1.~. 60 15.78 NOV. :.Sl?i 1.5121 11.90 11.08 DEC. 0.20 0.20 9.40 8.58 TOT,~L 3 l.8. 70 31.8.70 /[·65.90 444,6i-:·:: a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,25~ AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT [."INTTS a. b a. b RECORDED WHALEN RECORDED FT. LARM'n E YEAR FLOW 'BELOW AD.JUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1971 JAN. 0.00 0.00 9.30 8.48 FE?. 0.00 0.00 9.20 8.38 !"'IAR. 0.20 0.20 15.00 14.1:3 ~ APR. 113.212) 113.20 147.10 145.45 MAY. 279.00 279.00 433.30 430.36 JUNE 321. 812) 321.80 408.10 405. 16 JULY 150.10 150. 10 171.00 168.06 AUG. 73.90 73.90 79. 10 76.16 SEPT. 20.80 20.80 30.70 27. 7,~ OCT. 6.70 6.70 19.60 18.78 NOV. 0.60 0.60 14.510 13.68 DEC. 0.40 12).40 12.80 11.98 TOTAL 966.7121 966.70 1349.60 1328.30

1972 .JAN 0.20 0.20 10.60 9.78 FEB. 17.130 17.00 25.90 25.08 MAR. 125.00 125.00 136.70 135.88 APR. 20.20 20.20 32.~0 30. 3~j t1AY 45.20 45.20 57.40 54.46 JUNE 11.0.80 110.80 114.80 111.86 JULY 93.80 93.80 97.10 94.16 AIJG. 66.80 66.80 69.10 66.16 SEPT. 18.70 18.70 24.70 21. 7,~ OCT. 5.70 5.70 14.10 13.:28 NO'-J. 1. 10 1.10 11.00 10. 18 .... 1-.-'1. DEC. 0.20 0.20 8.50 l • '-IV TOTAL 512)4.70 504.70 601.20 579.90

1973 JAN. \2). 10 0.10 8.80 7.98 ...... '0 .- 1:...... 0.00 0.00 7.50 MAR. 6.70 6.7121 15.40 14.58 APR. 85.20 85.20 111.90 110.25 t1AY 206.0121 :~:::06. 00 394. '20 391.26 ·JUNE 382.40 382.40 402.20 .JULY 214.4121 214.40 221.30 218.36 .-:."7=' OL AUG. 230.60 230.60 238.90 ..;,..-.....i~. :' I-J SEPT. 97. 10 97.10 117.70 114.76 OCT 12.10 12.10 29.7~ NOV. 2.70 2.70 20.70 19.8E DEC. 0.30 0.30 15.60 14.78 TOTAL 1237.60 1237.60 1 ~j83. 40 a Source: Point Flow Study, North Platte River, wyomIng - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF~9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1~00 AC-FT UNITS a b a b =, RECORDED WHALEN RECORDED i ! .. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1974 JAN. 0.10 0. 10 13.80 12.98 FEP.• 3.00 3.00 15.80 14.98 MAR. 238.90 238.90 258.60 257.78 APR. 225.00 225.1£)0 245.20 243.55 MAY. 82.40 82.40 94.80 91.86 JUNE 151£).60 150.60 154.60 15 1. 6.~ JULY 117.15.00 105.00 113.60 11 eJ. 6h AUG. 67.90 67.90 70.10 67. 1.~ SEPT. 17. liZI 17.10 21.30 18.36 OCT. 7.60 7.60 16.40 15.58 9 --:'0 NOV. 0.40 0.40 ltll.t0 • ...:...r~J DEC. 0.10 0.10 8.30 7.48 TOTAL 898.10 898.10 1022.90 1001.60

1975 JAN. 0. 10 0.10 8.20 7.4tll FEP.. 0. 10 0. liZ) 8.50 7.7v.') MAR. 0.00 0.00 8.70 7.90 APR. 13.60 13.60 22.10 20.50 MAY 31.40 31.40 32.00 29.14 JUNE 57.30 57.30 57.10 54.24 .JULY 122.20 122.20 123.90 121.04 AUG. 83.80 83.80 84.3121 81.44 SEPT. 27.90 27.90 31.10 ·::8.24 OCT. 7.60 7.60 18.20 17.40 NOl'; • 1ZJ.50 0.5ea 11.5ea 10. 7G DEC. 121. 10 0.11ZJ 11. 11ZJ 1121.30 TOTAL 344.61ZJ 344.60 416.21ZJ 395.50

1976 JAN. 0. 10 IZJ. 1121 7.30 6.61 FEB. 0.00 0.00 9. 10 8.41 MAR. 0.0121 0.00 8.71ZJ 8.01 APR. 9.00 9.00 15.40 14.02 .... , l"7 MAY 28.7121 28.7121 38.9121 ..!to. 'f . .J .JUNE 39.40 39.40 42.SIZJ 40.03 .JULY 103.40 103.4121 103.40 100.93 AUG. 66.3121 66.30 71.60 69. 13 SEPT. 27.70 27.70 31 • '~0 28.53 OCT 10.20 10.20 17.60 16.91 NOV. 0.40 0.4121 6.912l 6.21 DEC. 0.1f2l 0. 10 7.60 6. '=? 1 TOT(\L 2iJ~). :'W) :~~8S. ~_~0 359.!30 341 • S/t?i

a Source: Point Flow Study, North Platte River, W~Qming - NebrasKa, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Op~ration Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

leJIZ)0 AC-FT UNITS h a. b a. I-' :=T RECORDED WHALEN RECORDED I I. LARAl1IE YEAR FLOW BELOW ADJUSTED FLOW AT AD.JUSTED -T WHALEN FLOWS ,.. ! • LARAMIE FLOWS

1977 .JAN. 1Z).10 0. 10 6.60 6.00 FEE.• 0.10 0.10 5.80 5.20 MAR. 0.~0 0. III 0 6. 10 5.5lij APR. 4.80 4.80 11ll.41ll 9.21 MAY. 39.30 39.3(2) 43.20 41.07 -, c;; .JUNE 32.80 32.80 36.70 .~<+ • ...J , .JULY 92. [3(2) 92.8(2) 95.40 93.27 AUG. 53.80 53.80 65. 10 62.97 SEPT. 28.80 28.80 '30.90 28. 77 OCT. 1. 90 1. 90 5. 9 III 5.30 NOV. 0.B0 0.80 6.00 5.40 DEC. 0.40 0.40 6.60 6.00 TOTAL 2~j5. 60 255.60 309. 1+0 294.00

a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

lf2)f2)0 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1941 .JAN. 17.10 16.44 65.40 65.27 FEB. 16.50 15.84 64.60 64.47 MAR. 16.50 15.84 70.50 70.37 APR. 11. 10 9.78 66.90 6·~. ,~4 MAY. 64.70 62.34 56.50 56.04 .JUNE 64.60 62.24 76.00 75.54 .JULY 67.10 64.74 27.90 27.44- AUG. 78.50 76.14 23.20 22. 74 SEPT. 55.90 53.54 45.50 45.04 OCT. 23.70 23.04 100.80 100.67 NOV. 23. 10 22.44 87.30 87. 17 DEC. 30. 10 29.44 74.20 74.07 TOTAL 468.90 451.20 758.80 755.50

1942 .JAN. 27.3(2) 26.48 79.2121 78.98 FEB. 19.80 18.98 78.80 78.58 MAR. 16.20 15.38 88.50 88.28 APR. 28.40 26.75 84.20 83.76 MAY 227.80 224.86 340.121121 339.21 JUNE 67.00 64.06 115.90 115. 11 JULY 84.60 81.66 46.10 45.31 AUG. 73.80 70.86 40.40 39.61 SEPT. 53.00 50.06 72.20 71.41 OCT. 31.20 :.30.38 121.90 121 .6E; NO\..'. 37.40 36.58 114.40 114.1S DEC. 41.00 40.18 116.20 1151198 TOTAL 707.50 686.30 1306.80 131211.10

'L943 .JAN. 38. ~j0 37.69 116.90 116.73 FEB. 29.100 28.19 101. 40 1101.23 MAR. 34.80 33.99 102.50 1.~2. 3:3 APR. 55.00 53.38 127.70 127,36 MAY 53.40 50.51 77 . ~j0 76.8-=;;' .JUNE 57.00 54.11 .~7. 80 67.1s" .JULY 81. 50 78.61 31. ~j0 30.89 AUG. 74.50 71. 61 24.00 23.39 SEPT. 46.90 44.01 50.60 49.99 OCT 25.20 24.39 90.50 90.33 NO\".'. 30.80 29.99 107.10 106.93 DEC. 27.50 26.69 93.50 93.33 TOTf-,L. 5:3'+. H~ 533.20 991. v)L0 986 •.-:,(71 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT UNITS a b a_ lJ RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD,jUSTED STATE LINE FLOWS LEWELLEN FLOWS

1944 .JAN. 24.80 24.08 92.50 92.32 8 Q ...,.--::. FEB. 19.60 18.88 89.90 ,. ( .... MAR. 19.20 18.48 101.40 101.2-.2 APR. 22.40 20.97 88.80 88.44 MAY. 69.20 66.65 103.80 103. 16 ,JUNE 62.90 60.35 81.10 80.46 ...,.1 JULY 78.30 75.75 72.40 ( .I. • 76 AUG. 72.50 69.95 44.40 43.76 SEPT. 48.10 45.55 64.70 64.06 OCT. 24.30 23.58 105.90 105.72 NOV. 26.70 25.98 109.60 109.42 DEC. 24.40 23.68 94.30 94.12 TOTAL 492.40 473.90 1048.80 l044. 2~0

1945 JAN. 25.10 24.28 88.40 88. 19 FEB. 22.5~ 21.68 89.90 89.69 MAR. 27.40 26.58 95.00 94.79 APR. 21.70 20.~5 91.60 91. 17 MAY 99.50 96.56 125.30 124.54 JUNE 94.40 91.46 182.70 181.9/+ ·JULY 74.00 71.06 55.80 55.04 AUG. 68.90 65.96 92.00 91.24 ...,t:..,c'-c. ,. 65.10 62.16 87.50 8.::'.74 OCT. 35.20 34.38 138.20 137.9S( NOV. """-...1 • 10 32.28 111.60 111.39 01 DEC. 32.60 31.78 92.20 '.I. • 99 TOTAL 599.50 578.20 1250.20 1244.70

1946 .JAN. 33.50 32.80 102.50 102.33 FEF.• 29.30 28.60 91.20 91.G3 MAR. 32.20 31.50 117.)2.60 102.43 APR. 18.00 16.59 76.40 76.06 t1AY 40.80 38.29 81. 10 :=:0.49 JUNE 58.90 56.39 57.40 56.7S' JULY 66.90 64.39 .-'1.:,-+ • 10 33.49 AUG. 67.50 64.99 21.20 213.59 SEPT. 43.00 40.49 87. 10 86.49 OCT 31.10 30.40 126.40 121S.23 NOV. 29.60 28.90 118.40 118.2:3 DEC. 32.60 31.90 98.30 98. 13 TOTf\L 4EUc 1+0 4(j:-S. :::':0 996.70 99~-:-~ • J'~-)

a Source: Point Flow Study, North Platte River~ Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WrTH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1'947 JAN. 30.50 30.50 94.50 94.50 FEB. 26.20 26.20 87.30 87.30 MAR. 28.20 28.20 94. 10 94. 10 APR. 23.':'0 21.99 80.90 80.47 t1AY. 38.80 35.93 56. :j0 55.73 .Jt.JNE 122.90 120.03 216.50 215.73 .JULY 74.80 71.93 159.00 158.23

oj -: AUG. 6':'.80 63.93 38.90 38. J. •..J SEPT. 1+5. l0 42.23 73.20 72.41 OCT. 30.3Ql 29.50 123.80 123.58 NOV. 31.20 30.40 120.60 120.38 DEC. 35.10 34.3f{) 120.90 12iZ • .~,8 TOT(-\L 553. ~"50 532.70 1266.20 1260.60

Q ....:...... (71 1948 .JAN. 34.70 34.70 I~. /1(.) 92.70 FEP.• 32.90 32.90 107.80 107.8Vj i1AR. 56.90 56.90 128.70 128.70 APR. 33.00 31.35 94.50 Ci',,+. 11 MAY 44.00 41.06 56.50 55.81 JUNE 61.20 58.26 95. 10 94.41 .JULY 77.10 74. 16 77.90 77.21 AUG. 81.90 78.96 58.20 57.5L SEPT. 58.40 55.46 82.6~ 81.91 ()eT. 38.70 37.88 126.80 12,S.61

1'!rt .L~ NO\J. 41.30 40.48 119.80 .... .L ., • '...J J. DEC. 36.70 35.88 96.40 '7't... 21 TOTAL 596.80 575.50 1137.00 1132.00

1949 JAN. 31.70 31.70 70.20 70.2l(; FEB. 33.70 33.70 110.20 110.20 MAR. 28.30 28.30 123.00 123.00 1 1 APR. 26.70 25.23 91.50 91. ... J. t1AY 33.~0 30.38 87.60 86.91 .JUNE 72.60 69.98 118.50 117 .81 / ...... JULY 71.70 69.08 43.80 ,,+.":; • 1 . AUG. 70.00 67.38 47.70 47.01 SEPia 42.70 40.08 90. ~~0 89. 8"~ OCT 34.70 33.96 126.70 12,~. =11 .-,....,. NOlJ. 28.50 ~, 7l~ 112.30 112. 11 DEC. 31.3~ 30.56 106.40 10t~. 21 TOTAL '.'j1ij4.90 485.90 1 ~i.28. 40 i 123.40 a Source: Point Flow Study, North Platte River, Wyoming - NeDraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,2S~ AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1950 JAN. 32.60 31.91 95.00 94.82 FEP·. 31. 10 30.41 102.80 102.62 MAR. 31.40 30.71 1~0.20 t00.02 APR. 15.70 14.32 7'1.80 71.44 MAY. 32.70 30.:24 56.60 55.95 -r""'! JUNE 57.40 54.94 33.80 o-J.~. 15 .JULY 68.20 65.74 58.40 57. 7~:" AUG. 57.20 54.74 68.30 67.b5

-1 "': SEPT. 49. '10 47.44 119.80 119. J. ,J OCT. 33.40 32.71 131.50 131.32 NOV. 29.20 28.51 113.00 112.8'.2 DEC. 34.20 33.51 115.70 115.52 TOTAL 473.00 455.20 1066.90 1062.2(2)

1951 JAN. 29.40 28.76 92.80 92.t~0 FEP.• 27.80 27. 16 92.40 92.213 MAR. 22.80 22.16 84.50 84.30 APR. 19.10 17.82 73.80 73.40 MAY 31.70 29.42 63.70 b2.98 JUNE 36.50 34.22 t03.40 102.68 .JULY 56.50 54.22 86. 10 85.38 AUG. 61.30 59.02 52.70 51.98 SEPT. 39.90 37.62 161.50 1,~0;J 78 (;{:T. 47.90 47.26 146.70 146.50 NOl,,). 38.30 37.66 127.2£0 127.J0 DEC. 26. 10 25.46 88.80 88. 6\~ TOTAL 437.30 420.80 1173.60 1168.40

L 1952 JAN. :~4. 20 23.38 89.'20 88.91 FEr. • 23.60 22.78 91.40 S:1.19 MAR. 28.50 27.68 114.30 114.09 APR. 49. 15 47.50 114. 10 113.68

-I -:.-:' 7~ M~", MY 112.20 109.26 1. •...1 ..... • O.J'l.J 131. 5 ~j .JUNE 198.00 195.06 180.30 179.55 .JULY 69.30 66.36 47.70 46.9:5 AI)G. 69.70 .....J..' 0. 76 38.60 37.85 j'-:' i <=, SEPT. 52.70 49.76 72.90 { .a:..._ .t. .J OCT 38.00 37 . 18 128.70 128.49 "'1~ NO'.,}. 32.~0 '-1 L • 18 127.80 127.59 .,.,..- ... Ut:..l..". • 33.80 32.98 119.90 119.b9 TOTt"L. 7·~:2. 1.0 700. ii0 1237.20 -:.' .."23111 !3~-;} a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water a.nd POIIJer ReSOLtrCes Service, .Ju.ly 1980.

b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

100~ AC-FT UNITS a b a ;,J RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD,JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1953 .JAN. 32. 10 31.51 104.90 104.74 FEB. 27.70 27. 11 91.70 91. 54 MAR. 29.40 28.81 101.9~ l01.74 APR. 19.50 18.32 83.60 83.28 MAY. 27.70 25.59 56.4~ 55.83 JUNE 41. 10 38.99 59. 10 58. =.3 JULY 65.90 63.79 31.00 30.43 AUG. 51.61ll 49.49 83.40 82.83 -r-r SEPT. 42.~0 39.89 48.9121 48. '-1'_' OCT. 26.70 26. 11 95.9121 95.74 q...,. NOV. 22.70 22. 11 97.6~ ,I. 44 0-' DEC. 20.60 20.01 87.40 ,..,){ .24 TOTAL 407.20 391.91lJ 941.8~ 937.70

1954 .JAN. 17.51lJ 17. 1'-:'.:.. 79.210 79. 10 FEB. 14.21lJ 13.82 74.2~ 74a 10 MAR. 15.30 14.92 97.40 97.3~ APR. 11. lllJ 10.33 63.31lJ 63.09 MAY 11.21lJ 9.83 50.51lJ 50. 13 .JUNE 22.81lJ 21.43 26.60 2,:;'.23 JULY 50.40 49.03 10.40 10.103 AUG. 48.40 47. III 3 19.40 19.03 '-I-i 07 SEPT. 32.30 30.93 22.20 ~ J. 11 '..,J'-1 OCT. 9 .4~ 9.1212 53.50 53. 4~:; NOV. 15.9lZl 15.52 70.0iZi 69.=/0 i-r DEC. 13.S~ .L~. 12 72.30 7'2 A '2~~ 1..·.. )1 '-1 !?I TOTAL 262.0~ 252. 10 624.00 '-J";".l.. '_'~

1955 .JAN. 13.2121 12.82 60.50 ,~0. 39 FEB. 10.90 10.52 60.20 60.09

1"'7 -! .~. M,t;R. 13.50 J.o...J. .I...:.. 78.20 78.09

:..~ oe, APR. 14.60 13.83 66.20 W...J. rr~ MAY 22. 50 21. 13 47.50 47 10

~-r ,JUNE 37.70 36.33 _i"..J • 10 52.70 .JULY 53.90 52.53 33.70 33.30 AlJG. 43.90 42.53 12.70 1 L. ""':'¥;]

SEPT. 32.20 30.83 29.90 29 r. sv; OCT 15. 10 14.72 70. 10 J~9. 99 NOV. 17. ::-~0 16.82 74.80 74. ~:9 -, /, =. C;1 DEC. 17.00 16.62 74. 70 j"""T.~t TOTt'\l_ 2), 9. 7~ :? '1.1. ll-\0 h61 • (;0 ,L.:/~8. '(Ii)

a Source: Point Flow Study, North Platte River, Wyoming - Nebrask~, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and A'ssociates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,25~ AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT UNITS d- b a. RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD,JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1956 JAN. 14.90 14.46 72.80 72.70 FEB. 12.30 11.86 62.70 b2 •.':J0 MAR. 13.20 12.76 67.20 67.10 APR. 11.80 10.93 49.60 49.41 ...,. .. 1;:; MAY. 22.70 21.14 31.50 ..j .1. • .1. • .1 JUNE 28.50 26.94 15.00 14.65 JULY 53.30 51. 74 52.20 51.85 AUG. 64.90 63.34 11.50 11. 15 SEPT. .35.70 34.14 15.61£1 15. 2~ OCT. 9.20 8.76 48.41£1 48.30 NOV. 17.60 17.16 79.80 79.70 DEC. 16.70 16.26 69.70 69.6I;Q TOTAL 3~Q).8Q) 289.50 576. '~Q) 573. S(i)

1957 .JAN. 12.70 12.14 52.21£1 52.05 FEB. 11.60 11.134 67.10 66.95 MAR. 12.20 11.64 66.40 66225 APR. 12.50 11.39 68.70 68.41. MAY 57.50 55.51 113.30 112a78 JUNE 30.50 28.51 90.20 89.6::3 .JULY 69.70 .':J7.71 38.50 37.98 AUG. 67.50 65.51 45.40 44.8f3 SEPT. 38.60 36.61 69.70 1~9. 18 OCT. 27.00 26.44 90.60 90.45 NOV. 22.40 21.84 88.00 87.85 DEC. 20.70 20.14 83.10 82.9'.} TOTAL 382.90 368.50 873.20 869.40

19~)8 .JAN. 18.20 17.65 69.30 69.14 FEB. 15.70 15.15 67.00 .~t.'. 84 MAR. 16.50 15.95 81.50 81.34 APR. 20.10 18.99 90.20 89.88 MAY ~33. ·4-0 31.43 65.90 65.33 JUNE 25.40 23.43 101. 10 100.53 JULY 62.30 60.33 92.40 AUG. 72.20 70.23 30.40 '29&83 SEPT. 42.10 40.13 59.30 58.7:3 OCT 28.70 28.15 100.50 100.34 NOV. 23. 10 22.55 89.80 89.64 DEC. 23.10 22.55 87.20 87.04 TOTAL 380.80 366. ~j0 934.60 93~.50 a Source: Point Flaw Study, North Platte River, Wyoming Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,25~ AC-FT REPLACEMENT WATER AT FORT LARAMIE)

10"'0 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1959 JAN. 19.40 18.86 79.30 79.17 FEB. 15.70 15. 16 73.60 73.47 MAR. 17.20 16.66 81.1121 80.97 APR. 17.30 16.23 78.80 78.54 MAY. 22.6121 2121.68 70.i2l121 69.53 .JUNE 28.30 26.38 34.10 33.63 IJULY' 63.1121 61. 18 19.70 19.23 AUG. 67.70 65.78 12.00 11. S3 'f ""''''7 SEPT. 48. 1121 46.18 45.20 ~"l-. {·•. f OCT. 29.20 28.66 113.70 113.57 NOV. 21.2121 2121.66 87. l0 86.97 DEC. 18.70 18.16 81.80 81. .~7 TOTAL 368. ~jl2l 354.6121 776.40 773.00

1960 JAN. 16.00 15.52 67.00 66.90 FF.::E.• 15.70 15.22 70.40 70.31ij Q'"'! MAR. 17.90 17.42 93.2121 1·-1 .. 10 APR. 14.8121 13.84 65. :::-~12l 64.99 t1AY 8.40 6.69 47.9121 47.53 JUNE 32.10 30.39 17.60 17. 2~3 ·JULY 73.40 71.69 7. 10 b. 73 AlJG. 64.80 63.09 12.10 11. 7~;

--:'1 -r~ SEPT. 35.40 33.69 22.10 ..;... J. • , ....} .' c:; OCT. 16.60 .16.12 65.20 0...;. 10 NOV. 17.0121 16.52 72.30 72.20 DEC. 17.10 16.62 65.30 65. 2~0 TOTAL 329.2121 316.80 605.40 602.70

1961 JAN. 15.50 15.07 65.40 65.29 FEB. 12.1210 11. 57 64.50 64.39 MAR. 13.10 12.67 73.10 72.99 APR. 13.70 12.85 63.20 62.98 MAY 12.10 10.58 70.50 70. 11 JUNE 12.3121 10.78 27.20 26.81 ,JULY 75.8(2) 74.28 11.0121 10.61 AUG. 48.212'1 46.68 19230 18.91 .. , SEPT. 34.70 33.18 28. ~)12) 28. .I. .L OCT 19.30 18.87 79.00 78.89 NOV. 18.30 17.87 77.00 76.89 DEC. 17.0~ 16.57 7eJ.Q)Q) 1~,9. 89 TOT{~L 2'72~01l) 281.Q)0 ,~A8a ·ll.0 h4S. 9~'j a Source: Point Flaw Studw, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions fram Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SiTES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1!2l12l!2l AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1962 JAN. 11. 10 10.54 58.60 58.45 FEB. 14.10 13.54. 57.90 57.75 MAR. 15.80 15.24 73.80 73. 6~5 APR. 17.30 16.19 57.90 57.59 MAY. 43.00 41.01 62.70 ,:::2.1'1 JUNE 42.50 40.51 132.40 131.85 .jULY 1)9.30 57.31 105.20 124.65 AUG. 68.90 66.91 38.40 37.85 SEPT. 1+0.60 38.61 rj8. S0 57.95 OCT. 30.90 30.34 108.60 108.45 NOV. :~::0. B0 20.24 87.80 87.65 .... , ""71: DE:C. 18.80 18.24 74.50 {'+ •....J.J TOTAL 3b8.70 916. :.30 912. 3~j

1963 JAN. 14.20 13.65 63.70 63. 5.~ FEB. 16.10 15.55 89.20 89.06 r1AR. 19.30 18.75 95. 10 94.96 APR. 15.60 14.50 76.17.)0 75.72 MAY 41.60 39.64 35.40 34.90 JUNE 22.50 20.54 73.60 73. 10 .JULY 78 .. 60 76 .. 64 9.00 8.50 AUG. 67.50 65.54 17.60 17.10 SEPT. 41.20 39.24 71.90 71.40

~ ~ .-: -; L c)CT. 25.80 25.25 112.50 ... .L';"'c '-" • .1 NOV. 19.60 19.05 93.40 l=i3.26 16.20 15.65 76.30 TOTAL 378 .. 20 364.00 813.70 810.10

1964 .JAN. 14.a0 14.24 116.9~ 116.78 FEB. 13.90 13.34 101.40 101.28 MAR. 15.00 14.44 tlZl2.50 102.38 APR .. 170.10 168.99 127.70 127.47 t1AY 32. :30 30.31 77 . ~j0 77.09 .JUNE 42.00 40.01 -67.80 67.39 ,JULY 76.00 74.01 31.50 AUG. 71.51.Z1 69.51 24.00 23.59 SEPT. 37.00 35.01 5~ • .s~ 50. 1'·1 OCT 25.60 25.04 90.50 90.38 NOV. 19. '?0 19.34 1~7.l~ 106.9;3 DEC. 17.40 93.50 93.38 TOTAL 382. ~j0 368. 10 685.20 682.20 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEr{ PROJECT AT SELECTED SITES (WITH 11 , 250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

UZH210 AC-FT UNITS

a b ~- LJ RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD·JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1965 .JAN. 16.30 15.6121 77.70 77.5 L FEP.• 14.1121 13.4121 65.60 65.41 MAR. 14.00 13.30 58.:20 58.01 APR. 11.90 10.50 59.80 59.43 MAY. 66.90 64.4121 61.70 61.04 ·JUNE 112.90 110.40 203.80 2~3.14 .JULY 60.00 57.50 106.80 1.06.14 AUG. 67.20 64.70 46.40 45.74 SEPT. 41.20 38.70 98. 10 97.44 1--:.1:; --:·1 OCT. 32.80 32.10 125.40 .,;.,...J. ":"'.L NOV. 23.00 ~"22. 30 90.90 9fli.71 DEC. 20.60 19.90 94.6eJ 94.41 TOTAL 4:3121.9121 462.80 1089. v1fli 1084.20

1966 JAN. 17.3eJ 16.73 73.90 73.75 FEB. 13.60 13.03 73.30 73.15 MAR. 17.20 16.63 88.00 87.85 APR. 30.40 29.26 84.7fli 84.40 MAy 39.10 37.fli6 37.50 36.96 JUNE 40.50 38.46 54.7fli 54.16 .JULY 75.30 73.26 29.60 29.06 AUG. 58.90 56.86 53.7fli 53.1t.: 00 '-:'i.. SEPT. 39.70 37.66 99.80 f .' 2 ~'..J OCT. 25.10 24.53 111.00 i 10. 8::, NOV. 19.60 19.03 97.4fli 97.25 DEC. 17. 10 16.53 76. :jQj 76&35 TOTAL 393.80 379.eJ0 880.10 876.213

1967 JAN. 14.50 13.92 72.8eJ 72.64 FE?. 11.40 10.82 64.20 64.04- 1 1 .",:,--:, MAR. 11.8eJ ~ ... ~~ 68.50 68.34- APR. 10.40 9.23 51. 10 50.78 MAY 21 . I"? 0 19.81 57.10 56.53 JUNE 77.90 75.81 167.00 166.43 " i 1 .JULY 68.2eJ Ci(:j • .I. .I. 83.30 82. 7:3 AUG. 69.70 67.61 28.50 27.93 -"-1 SEPT. 43.90 41.81 73.310 ,I ~. ( .~ OCT 26.20 25.62 97.20 97.04 NOV. 23.00 22.42 91.60 91.44 DEC. 21.00 2~.42 70.80 70.64- TOT I-\\..._ ~99.90 384.::30 9":~5 • L~!{j 921. :3~~

a Source: Point Flaw Study, North Platte River, W~oming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WTTH AND WITHOUT THE CORN CREEh PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT UNITS a b a fj RECORDED STATE LINE RECORDED LEWELLEN YE(~R FLOWS AT ADJUSTED FLOWS AT AD.JUSTED STATE LINE FLOWS LEWELLEN FLCjWS

1968 ,JAN. 17. ~jQl 16.8121 72.80 72.63 FEB. 16.8121 16.10 76.10 75.93 MAR. 22.2121 21.5121 72.2121 72.03 APR. 42.50 41.09 10121.20 99.86 MAY. 45. ~;0 42.99 95.30 94.69 JUNE 98.70 96.19 116.1121 115.49 .JULY 74.90 72.39 31.80 31. 19 AUG. 57.00 54.49 76. 10 75.49 01 ='0 SEPT. 35.30 32.79 82. :,:'~0 1-/ .L • _.J ! OCT. 30.10 29.40 104.80 104.63 NOV. :22.9121 22.2121 94. :::-~0 94.03 DEC. 2121.50 19.8121 75.1210 74.83 TOTAL 483.90 465.70 996.::30 992.40

1969 .JAN 18.80 18.17 69.50 69.35 FEB. 16.2121 15.57 71.20 71 . 0~j MAR. 23.70 23.07 88.50 88.35 APR. 43.10 41.85 98.70 98.40 MAY 29.6121 27.36 75.60 75.06 JUNE 33.90 31.66 61.3121 60.76

.-:,""'1 ~'- JULY 75.70 73.46 23.9121 ~-.I" '..J'-/ AUG. 74.3121 72.1216 ·.20.50 19. 9,~ =...... ,.' SEPT. 41.40 39. 16 53.60 -t."j \I ;£,Sb

\)t.. ~ • 32.50 31.87 l31.90 13111 7:5 ·-'1 , ... NOV. 22.10 .:. .... '+1 111.1121 110.95 DEC. 1.8.30 17.67 86. :::3121 86.6:-; TOTAL 429.60 413.40 982 •.~0 888.70

1970 .JAN. 16 . l0 15.73 70.50 7121.32 FEP.• 14.30 13.93 74.60 74.42

MAR. 15.60 15.23 77. ~-;0 l / • '_',J.." .. APR. 22.60 21.86 89.1121 88. 74 t"lAY 55.00 53.67 82.20 81. ::16 ,jUNE 129.10 127.77 153.4121 152. 7.~ .JULY ::-15.20 83.87 59.20 58.56 AUG. 67.4121 66.07 35.60 34. 9,~, SEPT. 37.70 36.37 73. ~10 72.36 OCT 34.7121 34.33 129.4121 129.22 NOV. 25.80 25.43 111 • 20 111.02 DEC. 21.20 2121.83 80.60 80.42 TOTAL 254.70 245. H21 1036.30 l031.70

.. , I ( .~. Point Flow Study, North Platte River, Wyoming - NEor.='.Si

100~ AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD,JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1971 JAN. 19.80 18.98 79.40 79.05 FEP.. 16.70 15.88 73.20 72.85 MAR. 19.80 18.98 85.20 84.85 APR. 1"-0.80 139.15 163.10 162.40 MAY. 444.3~ 441.36 451. S0 ~50.26 JUNE 435.00 432.~6 524.20 522.96 ,JULY 174.1~ 171.16 185. 10 183.86 1'-' C::' AUG. 74.00 71.06 5~.8~ "f"1 • .Ju SEPT. 47.50 44.56 108 . .10 107.06 OCT. 35.30 34.48 126.30 125.95 NOV. 24.60 23.78 104.8~ 104.45 DEC. 21.30 2~.48 88.60 88.25 TOTAL 1453.20 1431.90 2040. :')0 2031.50

,""7 • ,"'"'\ 1972 JAN. 19.40 18.58 73.40 ( '....I. J."7 -"'0 OQ FEE. • '27.2121 26.38 80.:20 t l. ,. : t1AR. 136 •.~0 135.78 180.80 180.59 APR. 47.60 45.95 111.80 111 . 3'~~ MAY 50.80 47.86 84.80 84.07 JUNE 117.13.00 100.06 132.70 131.97 ,JULY 88.10 85. 16 77. QHZ) 76.27 AUG. 67.1~ 64.16 58. 10 57.37 SEPT. 35.00 32.06 96.30 °S.57 OCT. 31.17.10 30.18 "d~7. ~~0 106.79 NOV. 24.20 23.38 108.50 108~29 DEC. 18.0~ 17.18 85. 10 84.89 TOTAL 648.00 626.70 1195.70 11 ~'0. 40

1973 Jr~N. 17.00 16.18 85.:20 84.81 FEB. 15.70 14.88 72.00 71.,Sl MAR. 22. :20 21.38 95.70 95.31 APR. 106.10 104.45 149.30 148.52 t1AY 384.10 381. 16 411. 10 409.71 JUNE 415.90 412.96 439.60 438.21 JULY 220.6~ 217.66 205.6~ :~~~04. 21 AUG. 225.40 222.46 208.20 206.81 SEPT. 14\2).2~ 137.26 251.00 249.61 OCT 51.20 50.38 164.20 1'~13,,81

NOIJ. 33.90 33.08 124.3~ .:...&:..."' .-:" •..,J. 9:L qc:, 01 DEC. 26.70 25.88 99.20 I '-1. I..} .l.. TOT(-\L t 6:~)9. 00 l637.7v.1 23l~S. 'f-V)- ·.~:·295 • ~51~')

~ Source: Point Flaw Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980.

b Flow adjustments were made using simulated depletions from Banner and ,;s·:50ciates Gra.y Rocks Op"?ra.tion Stu.ay GRGFC39. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT UNITS a. b a. b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD.JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1974 JAN. 26.10 25.28 113.80 113.53 FEB. 23.50 22.68 94.50 94.23 t1AR. 258.40 257.58 276.70 276.43 APR. 262.20 260.55 323.10 32'2.55 MAY. 94.60 91.66 139.70 138.72 .JUNE 140.20 137.26 145.30 144.32 JULY 96.90 93.96 58. :::-~0 57.22 AUG. 68.10 65. 16 53.40 52.42 SEPT. 37.30 34.36 101.00 l (2}0. eL-:-~ OCT. 33.00 32. 18 120.40 120.13 NOV. 23.90 23.08 95.20 94.93 DEC. 21.30 20.48 94.50 94.23 TOTAL 1085. ~j0 1064.20 16l5. :30 1608.711i

1975 JAN. 18.60 17.93 89.90 89.74 FEP.• 15.B0 15. 13 81.80 81.64 MAR. 18.10 17.43 76.00 75.84 APR. 25.t-30 24.47 94.20 93.88 MAY 29.30 26.92 81.80 81.23 JUNE 50.40 48.02 76.20 75.6:.3 .jULY 105.90 lIZ13.52 59.70 59.13

AUG. 74. ::-30 72.42 37.50 36 n 9~3 SEPT. 42.50 40. 12 65.10 64.53 OCT. 31.30 30.63 107.20 107.04 N()IJ • 22.60 21.93 97.10 96.94 DEC. 20.60 19.93 96.60 96.44 TOTAL 455.70 438.50 936.10 932.00

1976 JAN. 17.90 17.29 93.90 93.75 FEB. 17.00 16.39 85.90 85.75 MAR. 15.50 14.89 73. 1 Ql 72.95 APR. 18.7121 17.49 73.10 72s80 MAY :33.5eJ 31.33 71.50 70.96 ·JUNE 40.00 37.83 57.80 .JULY :38.70 86.53 25.2Ql 24.66 AUG. 71.20 69.03 51.80 51.26 SEPT. 42.9Ql 40.73 72.30 71. 7,1.:, OCT 33.80 33.19 110.30 110.15 NOV. 19.80 19.19 88.40

r-,r.;: .-~c: DEC. 18.70 18.09 85.40 ,~_I. "::"...J TOTAL 417.70 4~2.00 888.70 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner a.nd A·:;sCJciate'5 Gray Racks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,25~ AC-FT REPLACEMENT WATER AT FORT LARAMIE)

1000 AC-FT UNITS a b a iJ RECORDED STATE LINE RECORDED LEWELL.EN YEAR FLOWS AT ADJUSTED FLOWS AT AD.JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1977 JAN. 15.90 15.39 67.90 67.76 FEB. 13.20 12.69 75.60 75.46 MAR. 13. 10 12.59 75.90 75.76 APR. 13.90 12.88 71.20 70.93 MAY. 31.00 29. l8 65.50 65.02 .JUNE 37.30 35.48 54.80 54.32 .JULY B0.50 78.68 28.50 28. 0':-~ AUG. 54.90 53.08 47.20 46.72 SEPT. 36.60 34.78 61.30 6~.82 OCT. 20.3121 19.79 88.50 88.36 NOV. 16.90 16.39 78.90 78.7,S DEC. 16.60 16.09 73.10 72.9.:S TOTAL 350.20 377.eJ0 788.40 784.90

a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Wat~r and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,2S~ AC-FT REPLACEMENT WATER AT STATE LINE)

101211" AC-FT UNITS a b a b RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW BELOW ADJUSTED FU:;W AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1941 JAN. 0.90 0.90 2.60 1.57 FEE.• 0.40 0.40 2.00 0.97 MAR. 0.70 0.70 2.40 1.37 APR. 2.40 2.40 5.30 3.24 MAY. 69.10 69. 10 78.50 74.83 ·JUNE 58.40 58.40 63.60 59. 93 .JULY 63. ~H~ 63.50 66.90 63.23 AUG. 69.90 69.90 73.40 ,S9.73 SEPT. 26.00 26.1il0 31.50 27.83 OCT. 1. Sill 1. 50 5.00 3.97 NOV. 2. 10 2. 10 4.50 3.47 DEC. 8.80 8.80 10.90 9.87 TOTAL 303.70 3~3.70 346.60 320.00

1942 .JAN. 1.30 1.3ill 4.20 2.94 FEB. 1.00 1.00 2.80 1.54 MAR. 1. 10 1. 10 2.80 1.~A APR. 16.60 16.60 24.70 22. 18 MAY 177.60 177.60 221.20 216s70 .JUNE 25.40 25.40 41.60 37. 10 JULY 87.40 87.40 92.80 S8.31ll AUG. 70.20 70.20 76. 10 71.60 SEPT. 24.30 24.30 31.40 26.90 OCT. 1.60 1.60 5.90 4. tiL;. NOV. 5.70 5.70 9.40 8.14 DEC. 7.20 7.20 11.20 9.94 TOTAL 419.40 419.40 524.00 491.40

~f7I '7;: 1943 .JAN. 7.90 7.90 11.50 J. ¥...I • -...I •• J :- t::.E.• 3.30 3.30 5.60 4.43 I"'IAR. 4.80 4.80 15.20 14.03 APR. 12.50 12.50 39.10 ·.,jb. /b M!-\Y 3.80 3.80

'",::'-:= I.... ·-~ SEPT. 21.l:i0 21.60 27.t0 .;.:..,...;.. 7 .~.:.

OCT 1.70 1. 70 5.40 .:.r.£.~ .-) 7-'1 NOV. 0. :50 0.50 3.50 .;.:.. • •....J • ..J DEC. 0.50 0.50 2.60 1.43 TOTr-\L 279. :Wi 279.30 ~5()4. (-,1lJ :.~64. ~3V)

21. Source: Paint Flol.1J Study, Nc)rth Platte Fhver, Wyoming - Nebr 2I.sk2l. ~ W2I.ter and POI.uer Resources Service, .July 1980 .

b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF~9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

I I~r ~ --c. 1000 AC-FT UI~.L i·..) a b a \J RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT AD.JUSTED WHALEN FLOWS FT. LARAMIE FLOWS

< "'"1' 1944 JAN 0.40 0.40 2.40 L. -..IQ FEB. 0. U!I 0.10 2.20 1- 16 1 t1AR. 0. ·40 0.40 2.20 .I. • 16 APR. 0.90 0.90 3.80 1. 72 I"IAY. 54.90 54.90 60.60 56.89 ,JUNE 50.90 5e1.90 56.50 52.79 .JULY 80. 10 80. 10 82.00 78.2(? AUG. 73.90 73.90 76.00 72.29 SEPT. 25.1210 25.00 30.60 26.89 OCT. 0.80 0.80 4.60 3.56 NOV. 0.60 0.60 3.50 ~ ~ 4t:,

1 ""1' DEC. 0.50 0.50 2.80 J.. ,0 TOTAL ·~~}38. 50 2BS.Sl2l 326.70 299.8(;j

1945 JAN. 0.40 0.40 4.20 3.02 FEB. 0.30 0.:30 2.80 1.62 MAR. 4.80 4.S0 2.80 1.62 '-:"-:' 77 APR. 1.70 1.70 24.70 ..:.,...,;.... '-/-..J MAY 69.50 69.50 221.20 216.97 JUNE 40.60 40.60 41.60 37.37 ,jULY 70.60 70.60 92.80 88.57 AUG. 59.40 59.40 76. 10 71.87 SEPT. 47.10 47. 10 31.40 27 17

~'''I OCT. 1.50 1 . :)0 5.90 4. { .\"'- ':::> .-:~.-) NOV. 3. 10 3.10 9.40 f-1 .... ~ DEC. 3.70 3.70 11.20 10. 0:~~ TOTAL 302.70 302.70 400.40 3,:S9.80

.-:' 7 !:;; 1946 .JAN. 2. 10 ..:... 10 4.50 '-f. --1 ..

FEB. ...) . 1!Zl 3.10 4.80 3.87 MAR. 4. :::-~0 4.20 6.00 5.07 7 APR. 1.80 1. 80 -..1. 10 Jc .24 77 r~IAY 32.h0 32.60 37.30 --1'-1 II 97 ,jUNE 45.50 45.50 47.80 44.47 .JULY 60.90 60.9(Q 64.00 60.67 AUG. 58.20 58.20 62.00 58.67

01 ~ 1- SEPT. 8.80 8.80 16.80 l·').£+l ,-,("T .-, 7r?1 '-" '\., , 2.30 .::.. • •....J'" 12.50 11.57 NOIJ. 1.20 1.20 7.40 6.47 T"',~"'" ''''':: 0, (oJ. ,-,I::. 0.90 0.90 3,80 ~. '-' " T()TAL 221.60 221.60 269.8(Q 245. /'lJ

a Source: Point Flow Stud~, North Platte Riyer~ Wyoming Water and Power Resources Seryice~ July 1982. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,25~ AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a, h RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1947 .jAN. 12).4'21 12).412) 2.70 1.62 FEB. 0.50 0.50 2.30 1.22 MAR. 0.90 0.9'21 5.3'21 4.2'2 APR. 1.00 1. 00 5.212) 3.04 MAY. 23.312) 23.312) 35.40 31.55 JUNE 61.612) 61.60 108.60 104. 75 JULY 39.412) 39.412) 66.30 62.45 AUG. 61.70 61.70 71. 50 ,~7 .65 SEPT. 22.512) 22.512) 31.20 27.35 OCT. 2. 10 2. 10 9.80 8. 72

'-1 .-,,-, NOV. 12).30 0.30 3.312) ~ . ...::..~ DEC. 0.30 0.30 5.00 3.92 TOTAL 214.00 214.00 346.70 318.80

1948 JAN. 1. 40 1. 40 7.30 6.28 FEP.• 1.70 1.70 6.40 5.38 MAR. 26.50 26.50 30.70 29.68 APR. 1. 70 1.70 9.I7.HZI 6.97 MAY 25.10 25.10 32.40 28.77 .JUNE 31.70 31."70 46.80 43. 17 ·JULY 62.40 62.40 69. 10 65.47 AUG. 60.10 60.10 67.60 63.9"1 ec.·o'T -...II-, 18.21ZJ 18.20 25.80 22. 17 OCT. 2.70 2.7~ 9.70 8.6:3 NOV. 1.60 1. 60 5.60 4.58 DEC. 0.40 0. ·40 3.70 2. t.(-3 TOTAL 233.50 233.50 314.30 288. ;2}0

.-:' 0; 1949 0 • .30 0.30 4.00 .a:.,.. I ( FEE.• 0.30 12).30 4.50 3.47 '-:, q, MAR. 1. 60 .1.60 4.00 ~. I (

.-:~ .",":, i, APR. 2.10 2. 10 4.30 ..:...... ;..-:- t1AY 7.30 7 .30 15. 10 11.43 1::.0 c:.-:r .JUNE 20.80 20.8121 63.20 _, ,.. _1'--1

1 .jULY 79.412) 79.412) 87.60 83. '=7 ] AUG. 70.912) 70.90 77.20 73,.53 SEPT. 16.612) 16.60 23.30 19.63 OCT 3.20 3.20 12.80 11. 77 NOly". 4.90 4.90 12.40 111137 DEC. 7.70 7.70 11. 10 10.07 TOT(\L ~~ .L :5. lei 2LS.10 :3 L9. h0 :~~93 n 0~') a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a (j RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1950 JAN. 5.90 5.90 9.30 8.32 FEB. 2.50 2.50 4.90 3.92 MAR. 5.20 5.20 7.50 6.52 1 ...,. APR. 2. 10 2. 10 --.~. -.J1Li'7171 ~ •.,j",+ MAY. 21.00 21.00 26.50 23.01 .JUNE 61.30 61.30 67.20 63.71 JULY 62.60 62.60 69.9eJ 66.41 AUG. 57.90 57.9eJ 61. 50 58.01 SEPT. 17."2eJ 17.2eJ 24.80 21.31 OCT. 2.70 2.7eJ 9.70 8. t ", NOV. 1.40 1.4eJ 5.00 4. 0·~~ DEC. eJ.4eJ 0.412) 3.510 2.52 TOTAL 2'+eJ.2eJ 2l~0. 20 :293.20 267.91?J

1951 .JAN. 0.3eJ 12).30 2.60 1.69 1 -:q FEB. 0.20 0.20 2.30 L • •....1 I MAR. 0.20 0.20 2.2eJ 1.29 (~PR. 0. ll2l eJ.70 2.30 0.4(3 MAY 19.30 19.30 26.60 23.34' .jUNE 22.50 22.50 30.80 27.54 .JULY 61.40 61.40 68.60 65.34 AUG. :"55.90 55.90 65. :L0 61.84 SEPT. 14.90 14.90 21.30 18.04 OCT. 16. /:.,0 16.60 26.50 25.59 NOV. 4.00 4.00 7.70 If:,. 79 .-:' DEC. 0. 10 0. lea 3. 10 ..:.... 19 TOTAL 196.10 196.10 259.30 235.70

1952 JAN. 0.10 0. 10 2.80 1.54 FEB. 0. 10 0. 10 2.30 1. 04 MAR. 0.90 0.90 2.90 1.64 APR. 18.10 18.10 34.10 31.58 MAY 85.40 8S. /+10 103.20 98.70 .JUNE 157.40 157.40 177.20 172.70 .JULY 74.20 74.20 78.20 73.70 AUG. 72.10 72. 10 75.60 71.10 SEPT. 36.00 36.00 40.70 36.2~ OCT 6.50 6.50 16.00 14.74 NOV. 6.50 6.50 16. 10 14.84 DEC. 2.00 2.00 8.S0 7~34 TOTAL 459.30 459. ;30 557.40 524.8L<] a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF~9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREE~< PRO.JECT AT SELECTED SITES (WITH 11,2'50 AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a b RECORDED WHALEN RECORDED FT. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1953 JAN. 0.20 0.20 3.80 2.91£j FEB. 0.10 0. 10 3.10 2.20 MAR. 0.70 0.70 3.70 2.80 APR. 1.00 1.00 6.80 5.00 MAY. 21.40 21.40 23.30 20.08 JUNE 39.90 39.90 40.20 36.98 .JULY 72.60 72.60 73.80 70.58 AUG. 44.40 44.40 48.60 45.38 SEPT. 30.20 30.20 32.70 29.48 OCT. 1. 90 1. 90 8.00 7.10 NOV. 1.00 1. 00 6.90 6.00 DEC. 0.40 0.40 3.50 2. ,:S0 TOTAL ~:-~13. 80 213.80 254.00 230.7v.l

1954 JAN. 0.30 0.30 2.80 2.1121 FEB. 0.60 0.60 2.40 1.7Qi MAR. 0.50 0.50 2.50 1.80 APR. 0.20 0.:20 2. 10 0.69 MAY 6.40 6.40 6.80 4.29 .JUNE 21.70 21."1~ 21.30 18.79 ·JULY 54.20 54.20 52.80 50.29 Alj(5. 31.50 31.50 33.50 30.99 SEPT. 10.30 10.30 11. 10 8.59 OCT. 1.60 1.60 5.70 5.00 NOI./. 0.70 0.70 5.90 5.20 DEC. 0.50 0.50 2.70 2.00 TOTAL 128.50 128.50 150.0121 131.80

1955 JAN. 0.20 0.20 2.60 1. 85 FEB. 0.20 0.20 2. 10 1.35 t"iAR. 0. 10 0. 10 2. 10 1.35 APR. 0.60 0.60 2.50 1.01

MAY 11.30 11.30 11.80 9. J.."_' .JUNE 14.60 14.60 21.90 19.23 .JULY 52.90 52.90 56.lijf2) 53.33 AUG. 38.70 38.70 42.00 39.33 SEPT. 11.00 11.00 14.00 11.33 OCT 1.40 1. 40 6. 1!2) 5.35 N<)lv' • 0.90 0.90 6.20 5.45 DEC. 1. 50 1. 50 7.00 6.25 T<)T;\{_. l:33. LI-~l L33.1.1-1/.) l73.8lil l5 i r. -:)L0 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resour~es Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF~9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,2S~ AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a b RECORDED WHALEN RECORDED FT. LARAt1IE YEAR FLOW 'BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1956 .JAN. 1.30 1.30 6.50 5. 5~j FEE.• 0.90 0.9121 5.60 4.65 "'IAR. 0.8~ 12).80 6.3121 5. 3~j APR. 1. 30 1.30 5.60 3.70 i"1AY. 3121. 10 3121.10 29.90 26.50 .JUNE 45.70 45.7121 44.30 4121.90 .JULY 67.70 67.70 66.90 63. sri AUG. 7~.70 7121.70 72. oIII 68.60 SEPT. 21. S~ 21.5~ :23.:'30 2~. 1 vi OCT. 1.2~ 1. 20 5.8121 4. 8~5 NOV. 0.80 0.80 6.30 5. T5 DEC. 0.70 0.70 6.40 5.45 TOTAL 2'+2. 70 242.70 279.10 254.50

1957 JAN. 121.8121 ~.80 5.4~ 4.34 FEF.• 0.90 0.90 5.40 4.34 MAR. 121.6121 121.60 5.0121 3.94 APR. 1.00 1.00 5.80 3.69 MAY 33.40 33.40 53.3121 49.53 .JUNE 17.30 17.30 :.30.30 26.53 :::J 1 '--r .JULY 84.30 84.30 85.4121 '-!.1. • ~•• -! AUG. 73.80 73.80 79.10 75.33 SEPT. 23.90 23.9121 31.50 27 . ""'7]

OCT. 1. 90 1.90 1~.80 '=i L 7 i~ NOV. 0.9121 121.90 11. 1121 10.04 DEC. 0.70 0.70 10.90 9. 8!.~ TOTAL 239.50 239.50 333.80 306.50

19~18 .jAN. 0.70 0.70 9.60 8.57 FEr. • 0.60 0.612) 8.10 7.07 MAR. 0.70 0.7121 9.60 8.57 APR. 1. 121121 1.00 12.80 10.74 MAY 28.iI.l0 28.00 39.70 36.0"L ,JUNE 19.30 19.312) 23.90 :20 .. 21 .JULY 73. 'til 73.412) 76.60 72.9~ AUG. 81.20 81.20 83.2121 79a51

SEPT. 26.30 26.3121 3121.60 2,~ IS 91 a ':::>; OCT 2.50 2.50 9.90 '-i. j....J I NOV. 0.40 0.4121 7.90 6. :37 DEC. 0.90 0.9121 9.50 8.47 TOTAL 235.00 235.00 321.40 294. 7~~

Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEh PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a b -'"j RECORDED WHALEN RECORDED r- f. LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT AD.JUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1959 .JAN. 1. \.?l1Zl 1.0121 9.90 8.89 FEP.• 0.80 0.8121 7.5121 ,~, 49 MAR. 121.80 0.8121 8.90 7.89 APR. 1.10 1. 10 10.6121 8.58 MAY. 9. 1121 9. 1121 18.90 15.30 JUNE 30.6121 3121.6121 32.70 29.10 ,JULY 86.20 86.20 85.40 81.8(0 AUG. 71.90 71.90 73.40 69.80 SEPT. 31.80 31.80 34.90 31.30 OCT. 2.30 2.30 10.90 9.89 NOV. 0.30 0.30 8.50 7.49 DEC. 0.30 121.3121 8.00 6.99 TOTAL 236.20 236.20 31219.50 283.40

1960 JAN. 121.50 0.50 7. 10 6.22 FEB. 0.:20 0.:20 6.70 5.82 MAR. 13.713 0.70 1121.00 9.12 APR. 1. 20 1.2121 6.7121 4.94 MAY 10.8121 10.8121 1121.9121 7.75 JUNE 51-.5121 51.50 49.40 46.25 .JULY 94.1121 94. 10 92.813 89.65 AUG. 70.90 70.9121 71.80 68. ·~5 SEPT. 17.80 17.8121 18.60 15.45 OCT. 0.9121 13.90 4.30 3ft 4":: NOV. 0.3121 0.3121 5. 10 I..J.. --:::-:.' DEC. 0.90 13.90 6.10 5. 2:~ TOTAL 249.3121 249.30 289.3121 272.80

1961 .JAN. 121. lr0 0.40 5.30 4. 4~::-~ FE:;?. 0.30 13.30 4.80 3.92 MAR. 1. 00 1.0121 6.30 5.42 APR. 1.8121 1. 80 6.90 5. 14 t"lAY 1. 20 1.20 6.00 2 .. 8~j ,JUNE 16.60 16.60 23.30 20.15 .JULY 93.:20 93.:20 93.40 90.2:"5 AUG. 53. 10 53.10 53.70 50. ::,5 SEPT. 24.60 24.60 25.60 22.45 OCT 1. 00 1.00 5.60 4a72 NOV. 0. U~ 0. 10 5.90 5.0:2 DEC. 0.10 0. 1 III 6.00 s. 12 TOTt!\L. 193. ~~~ 193.40 2-4-2.60 21 S' ~ 8~~ a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF~9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

10e10 AC-FT UNITS a b a b RECORDED WHALEN RECORDED r i • LARAMIE YEf\R FLOW BELOW AD.JUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1962 IJAN. 0.00 0.00 5.70 4.67 FEB. 0.3\2) 121.30 7.7121 6.67 MAR. 1.20 1. '20 9.Sel 8.47' APR. 3.90 3.90 13.00 110.94 t1AY. l~3. 60 43.60 49.20 45.51 JUNE 12.80 12.80 25.90 22.21 JULY 60.80 60.80 68.30 64.61 AUG. 79.70 79.70 81.80 78. 11 '-:t; SEPT. 26.30 26.30 31.40 ~( 71

~ ~ 0.1" OCT. 5. 10 5. 10 12.90 ~ .L • '...J < NOV. 1. 70 1.70 8.80 7877 DEC. 0. 10 Ill. 10 7.50 6.47 TOTAL 235.50 235.50 321.70 295.00

1963 JAN. 0.00 0.00 5.40 4.34 FEB. 0.60 0 .• 60 8.30 7.2Lr MAR. 4.50 4.50 12.50 11.44 APR. 2.80 2.80 8.80 r~f. 6'7 MAY 55.30 55.30 54.50 50.70 JUNE 22.el0 22.17.10 26.40 22. 6(~: JULY 98.20 98.20 98.10 94.30 AUG. 74.60 74.60 75.80 72.0(7) SEPT. 21.30 21.30 28. 10 24.30 OCT. 2.7eJ 2.'10 8.50 7 .4';· NOI·.i. 0.80 0.80 6.60 ~'. 54 DEC. 0. 10 0. 10 5.6el 4.5'\· TOTAL 282.90 282.90 338.40 310.90

1964 .JAN. 0. 'lIZ! 0. 10 5.50 4.44 ' -, FEB. 0.00 0.00 5.40 '+ • ..,jOf MAR. 0. lei 0.10 6.40 5.34- APR. 1. 10 1. 10 8.90 ,:S. • ,. ..' MAY 28.40 28.40 40.20 36.40 ,1tJNE 39.2~ 39.20 45.60 41. :30 .JULY 97.70 97.70 97.50 93. 7~0 AUG. 80.20 80.20 81.00 77.20 SEPT. 24.60 24.6121 26. 10 22.3~ OCT 5.00 5.00 9.00 i • '"7' '+ NOV. 0.80 0.80 6.90 5,,84 DEC. 121.20 0.20 6.70 5.64 TOTAL 277.40 277 .4121 338.8121 311.30 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,25~ AC-FT REPLACEMENT WATER AT STATE LINE)

1012HZ) AC-FT UNITS a b a b .... T RECORDED WHALEN RECORDED r I • LARAMIE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1965 JAN. 0.20 0.20 5.9~ 4.68 FEF.• 0.40 0.40 5.80 4.58 MAR. 0.50 0.50 6.l0 4.8:;3 APR. 1.90 1. 90 6.30 3.86 ""'0 MAY. 76.7~ 76.70 82.50 ( '..J. U" JUNE 91.90 91.90 109.60 105.24- .JULY 64.70 64.70 68.40 64.04 AUG. 76. 10 76.10 77.60 73.24

.",:, ~ ""1!. SEPT. 2~.20 2~.2~ 25.70 ...:.. .L •.-/'""t OCT. 5.80 5.80 14.90 13.68 0 NOV. 1.50 1.50 9.40 '..J. 1 ~3 DE.C. 0.20 0.20 9. 10 7.88 TOTAL 3'+0. liz) 340. lID 421. l0 389.5Vi

""7 1966 JAN. 0.20 0.20 8.20 I • 13 FEB. 0. ::~0 0.30 7.90 6.8:3 MAR. 1.5it) 1. 50 10.60 9. ::.3 APR. 19.2121 19.20 256.70 254.57 MAY 56.70 56.70 55.50 51.69 .JUNE '1-0. b0 40.60 40.10 36.29 JULY 91.90 91.90 91.~0 87. 19 AUG. 57.30 57.3~ 58.20 54.39 SEPT. 21.30 21.30 24.20 20.39 OCT. Ql.30 0.30 6.30 5.2:::3 NO\,'. 0.0~ ~.0(z) 5.80 4.73 DEC. 12). ~~0 0.12Uz) 6.60 5.53 TOTAL 289.30 289.30 340.20 312.60

'L967 .JAN. 0.il)0 IiL ~~ 6.30 5.23 FEE.• 0.0Q1 0.00 5.00 3,. ·9-3 t1AR. ~. 'to 0. 10 5.40 4.33 APR. 2. 10 2. 10 5.30 3.1tl MAY 13.60 13.60 19.50 1.5.67 .JUNE 48.80 48.80 72. '1'0 69.07 .JULY 65.30 65.3~ 78. :50 74.67 Al...lG. 81. 50 81. 50 83.80 79.97 SEPT. 29.40 29.40 32.30 28.47 OCT 4.80 4.8el 10.40 9.33 NO\,'. 3. 10 3. 10 11.40 10.33 q .... - DEC. 2.50 2.50 10.60 , " :J.~ TOT('~L 2~j 1.20 :?S 1.20 :;:;L\-: • :'~0 313.6f:}

a Source: Point Flow Stud~, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, Jul~ 1980. b Flow adjustments were made using simulated depletions from Banner a.nlj !~,:-;soci.ate':"S Gray Racks Operat ion Study GH5F~9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CHEE~< PRO.JEeT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

10~0 AC-FT UNITS a b a lJ RECORDED WHALEN RECORDED FT. LARAr1IE YEAR FLOW P.ELOW AD·JUSTED FLOW AT AD.Jl")STE"O WHALEN FLOWS FT. LARAMIE FLOWS

1968 .JAN. 3.00 3.00 12.40 11 . 13

.-, ·~I FEB. ~. 10 ~. 10 11.40 10. 13 MAR. J.0.80 110.80 18.50 17.23 APR. 210.20 20.20 34.50 31,.97 !"IAY. 27.50 27.50 1+5.40 40.8:]

'~'171 JUNE 8 .... 'CJ 8.20 105. 10 100.58 .JULY 96.60 96.60 97.30 92. 7:':~ ' c. AUG. 63.20 63.20 O-J. 10 b~.58 SEPT. '21 . L~0 21.410 24.70 '~'171....fLJ. 18

t .. ' I..., t • 3.913 3.90 11- 10 9.83 ..., NO'';. 1.20 1.20 9.210 r IJ 9:.:~ ..... c. ... DEC. 1.00 1. 00 8.80 ( :a -,.~ TOT(-\L 333.70 333.71{j 4/+2.70 410. ~L ~()

0 1969 JAN. 0.90 0.90 9.30 '-J • 1,~ "7 .' FEE.• 1. ~0 1.00 8. rj(2i 7 a '0-10 MAR. 15.80 15.80 22. 10 20.96 APR. :30.40 30.40 36.90 34.63 .,.1 ..... MAY 35.30 35.30 35.40 •...J L • .~,,+ .JUNE 23.30 23.30 26.00 21.94 ·JULY 81.71!1 81.70 91.90 87.84 AUG. 85.90 85.90 86.70 8Lu .~4 SEPT. 29.20 29.20 30.20 ":::b. 14 OCT. .~. 30 6.30 13. '20 12. liJ"::! NOV. 0.90 0. '7'0 8.50 l • 3r~f DEC. 0. 10 0. H~ 7.20 6.06 TOTAL 310.80 310.80 375 • .90 346.40

1970 JAN. 1.00 1.00 7.20 6.38 FEF.• 0.012) 0.00 6.20 5.38 MAR. 0. 10 0. 10 6.90 6.08 APR.. 5.30 5.30 17. 10 15.45 MAY 39.50 39.50 62.90 59.96 oc. 1 .J!"'!NE 85. 10 '..J_ • 10 131.40 : 28. 4.:S .jULY 84.30 84.30 96. :30 '71 3.86 ..,.-:. '-:,,L AUG. 73.40 73.40 75.20 { ~. ~'-'

'''':10{ :~L :3EPT. 21.90 21.90 24.80 ~.I. • '-I'.,.} OCT 6.40 6.40 16.60 15.78 1 1'.10 ./. 1.50 1.50 11.90 11.0f; DEC. 0.20 0.20 '""( • 'H!J 8.58 TOTAL 31.8. 70 3°tS.70 465.90 433. 3C~} a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, Jul~ 1980.

G Flow adjustments were made using simulated depletions from Banner ,:."nd ,-'4.·:5~;oci.a.tes Gr'ay Rocks Opera.til.Jn Study GRC:iF09.- NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a b RECORDED WHALEN RECORDED r- l • LARAMIE YEAR FLOW :BELOW ADJUSTED FLOW AT AD.JUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1971 .JAN. 0.00 0.00 9.30 8.04 FEB. 0.00 0.(2)0 9.20 7.94 MAR. 0.20 0.20 15.00 13.71+ APR. 113.20 113.20 147. 1\2) 144.58 MAY . 279.0(fj 279.iI.)0 4:33.3(0 4281\ 8v.l .JUNE 321.80 321.80 408. 10 *03.60 .JULY 150. L0 1 :)0. 1 \2) 171.00 166.50 AUG. 73.90 73.90 79.10 74.60 SEPT. 20.80 20.80 30.70 26.2itl OCT. 6.70 6.70 19.60 18.34 1 - .-.' NOV. 0.60 0.60 14. :"'50 ~.~'+ DEC. 0.40 \2).40 12.8\2) 11.54 TOTAL 966.70 966.7\2) 1349.60 1317.00

o '71 1972 .JAN 0.20 0.20 10.60 I ••-,"to FEB. 17.00 17.00 25.90 24.64 MAR. 125.00 125.00 136.7\2) 135.44 APR. 2(2).2(2) 20.20 32.0(2) 29.48 MAY 45.20 45.20 57.40 52.90 JUNE 110.80 110.80 114.80 110.30 .JULY 93.80 93.80 97. 10 92.60 AUG. 66.80 66.80 69. 1.0 64. 6 ill SEPT. 18.70 18.70 24. Ti2) 20.20 OCT. 5.70 5.70 14. 10 12.84 ..... NOV. 1. 10 1. • 10 11.00 74 DEC. 0.20 0.20 8.50 7.24· TOTAL 504.70 504.70 601. 20 568.60

1973 .JAN. 0. 10 0.10 8.80 7" 5t:~ FEP·. 0.00 0.00 7.5\2) 6.24 MAR. 6.70 6.70 15.40 14. 14 APR. 85.20 85.20 111.90 109 ..38 MAY 206.011 ·~~06. 00 394.20 389.70 ·JUNE 382.40 382.40 402.20 397.70 .JULY 214.40 214. ·40 221.:.30 216.80 AUG. 230.60 230.60 238.90 234.40 SEPT. 97. 1.0 97. 10 117.70 : 13. :~;)

'i .",:, ~ .-:' OCT .L..:.... 10 .... 10 29.7Qj 28.44 NOV. 2.70 2.70 20.70 19. 4/~ DE C. 0. 3~' 0.30 15.60 14.34 -r()"r (~t_ 1 :~2::.t;7 • li0 1237.h0 1 ~jf33. l~0 t (550.80 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980.

b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF~9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEh PRO.JECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a b r'" RECORDED WHALEN RECORDED i ( • LARAt1IE YEAR FLOW :?.ELOW ADJUSTED FLOW AT AD.JUSTED WHALEN FLOWS FT. LARAMIE FLOWS

1974 .Ji~N. (2). 1 (2) (2). 1(2) 13.80 12.5.:'," FEB. 3.00 3.00 15.80 14.54 MAR. 238.90 238.90 2:58.60 257.3/+ APR. 225.(2)0 225.00 245.20 "242. t;S;3 MAY. 82.40 82.40 94.80 90.30 JUNE 150.60 150.60 154.60 150. 10 .JULY 105.00 11215.00 113.60 109. llrJ AUG. 67.90 67.90 70.1(2) j~S. 60

J "T SEPT. 17. 10 1 ( • 10 21.30 1,~, & 80 OCT. 7 • 60 7.60 16.40 15 • 14 NOV. 0.4(2) 0.4(2) 10. 10 8.84 J DEC. 0.10 0. 10 8.30 ( .04 TOTAL 898. 113 898. 10 1~22.90 990. 3~1j

1975 .jAN. 0. 10 0.10 8.20 6.98

FEB. 0. 10 0.10 8.50 7 c 2f3 MAR. :£1.00 0.00 8.70 7.48 .-.,-, APR. 13.60 13.60 .:....::.. 10 19.,~7 MAY 31.40 31.40 32.00 27.6t~ .JUNE 57.30 57.30 57. 10 5"-:'..:... fb .JULY 122.20 122.20 123.90 119.56 AUG. 83.80 83.80 84.310 79n96

SEPT. 27.90 27 .90 31. 10 ~w. lb OCT. 7.60 7.60 18.20 1:::s II I~~j

NOV. 0.50 0.50 11.50 11Li.~w DEC. 0. 1.0 0. 10 11. 10 9.88 TOTAL 344.60 344.60 416.20 384.80

~ (~ 1976 JAN. Ia. 1.(0 0. Ha 7.30 6. ... ! FEB. 0.00 0.013 9. 10 ( . 99

t1AR. 0.00 0.013 8.70 7 h SS~ APR. 9.210 9.210 15.40 13. 19 !""IAY :?8.70 2E:.7(o 38.90 34.9:3 .JUNE 39.40 39.40 42.50 38.55 .JULY 1.03.40 1~3.40 1~3.40 99. 4~3 L.t::. AUG. 66.3\7) 66.30 71.60 .~7 • '-1-.1 SEPT. 27.7~ 27.7~ 31.00 27 .05 OCT 1~.20 1~.20 17.60 1·::J. *"'-

J: -r~."\ NOI.,,'. 0.40 0.40 6.90 ...! • l . i DEC. 0. 10 0. 10 7.60 ,S,. 49 TOTAL 285.30 "~~85. 30 359.80 331.20 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resour~es Service, July 1980.

b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT [JNITS

a b a LI CT RECORDED WHALEN RECORDED 1 !. LARAt1IE YEAR FLOW BELOW ADJUSTED FLOW AT ADJUSTED ~ .... WHALEN FLOWS t- ! • LARAMIE FLOWS

1977 .JAN. (2). 1(2) (2). 1(2) 6.60 5.59 '7C'\ FEE. • 0. 10 0. 10 5.80 4 . ( , MAR. 0.00 0.1t.l0 6. 10 5.09 APR. 4.80 4.80 10.40 8.38 MAY. 39.30 39.30 43.20 39.61.0 .JI,.,lNE 32.80 32.80 36.70 33.10 JULY 92.80 92.80 95.40 91.80 AUG. 53.80 53.80 65. 1 Q) 61.50 SEPT. 28.8eJ 28.8(z; 30.9(2) 27.30 OCT. 1. 9eJ 1. 90 5.90 4.89 NOV. 0.812) eJ.812) 6.0(2) 4.99 DEC.. 12).40 0.40 6 •.~iZl 5.59 TOTAL 255.612) 255.60 309.40 283.30

a Source: Paint Flow Study, North Platte River, Wyoming Nebt' .:'.sk-;l., Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (W I TH 11, '251ll AC-FT REPLACEI"IENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1941 JAN. 17. 1 III 16.44 65. 4 III 65.27 FEJ:.• 16.50 15.84 64.60 64.47 MAR. 16.50 15.84 71ll.SIll 70.37 APR. 11. 10 9.78 66.90 66.64 MAY. 64.70 62.34 56. Sill 56.04 JUNE 64.60 62.24 76.00 75.54 JULY 67. 10 64.74 27.90 27.44 AUG. 78.50 76.14 23.20 22.74 SEPT. 55.90 53.54 45. :j0 45.04 OCT. 23.70 23.04 100.80 100.67 NOV. 23. 10 22.44 87.3(2) 87.17 DEC.· 30. 10 29.44 74.20 74.07 TOTAL 468.90 !.~51 .80 758.80 755.50.

1942 JAN. 27.30 26.48 79. 2 III 78.98 FEP.• 19.80 18.98 7S.81ll 78.5G MAR. 16.21Zl 15.38 88. Sill 88.28 APR. 28.40 26.75 84.2(2) 83. 7/~1 MAY 227.80 224. S.:£-, 340.00 339.21 .JUNE 67.Q)0 64.06 115.90 115.11 .JULY 84.60 81 .• 66 46. 10 45.31 AUG. 73.80 70.86 40.40 39. r~.L SEPT. 53.00 50.06 72. 2 III 71.41

OCT. 31. :~0 30.38 :21.9(2) 121 M 6:~.1 NOV. 37.40 36.58 114.40 114. 1:3 1 1 c::; qc DEC. 41.17.10 40. 18 116.20 J. '" -!. I ' .. : TOTAL 71ll7.51ll 686.3(2) 1306.80 1301.10

1943 ,JAN. .38.50 37.71 116.'70 11.S.73 FEB. 29.00 28.21 101.40 101.23 MAR. 34.80 34.01 102.50 l02.33 APR. 55.i2l0 127.70 t"IAY 53.40 50.6(2) 77.50 76.89 .JUNE 57.i2leJ 54.20 .:S7.80 67.19 .JULY 81.50 78.7(2) 31. Sill 30.89 AUG. 74.50 71.71ll 24.00 23.39 SEPT. 46.90 44.10 50.60 49.9S' OCT 25.20 24.41 90.50 90.33 NOV. 30.B0 30.01 107. 10 DEC. 27.50 26.71 93.50 93.33 TOTAL 554.10 533.8Ql 991. V)0 986.60 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Racks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH t-\ND WITHOUT THE CORN CREE~< PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEr1ENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD·JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1944 JAN. 24.80 24.10 92.50 92.32 FEP.• 19.60 18.90 89.90 89.72 MAR. 19.20 18.50 101.40 101.22 APR. 22.40 21.12)1 88.80 88.44 MAY. 69.20 66.71 103.80 103. 16 ·JUNE 62.90 60.41 81.10 80.4':;' .JULY 78.30 75.81 72.40 71.76 AUG. 72.50 70.01 44.40 43.76 SEPT. 48. 10 45.61 64.70 64.06 OCT. 24.30 23.60 105.90 105. 72 NOV. 26.70 26.00 109.60 109.42 DEC. 24.40 23.70 94.30 94.12 TOTAL 492.40 474.40 1048.80 1044.20

',":.=. 1945 .JAN. .:..~. 10 24.28 88.40 88. 19 FEB. ~'22. S0 21.68 89.90 89.69 MAR. 27.40 26.58 95.00 94.79 APR. 21. 70 20.05 91.60 o·, 1 • 17 MAY 99.50 96.56 125.30 124.54 .jUNE 94.40 91.46 182.70 181. 94 JULY 74.00 71.06 55.80 55.04 AUG. 68.90 65.96 92.00 91.24 SEPT. 65. 10 62.16 87.50 86. 74 OCT. 35.20 34.38 138. ~~J2i 137.99 NOV. 33. 10 32.28 111.60 111.39 OEC. 32.60 31.78 92.20 91.99 TOTAL 599.50 578.20 1250.20 1244.70

1946 JAN. 33.50 32.82 102.50 102.33 FEP.. 29.30 28.62 91.20 91.03 t1AR. 32.20 31. 52 1Q)2.60 102.43 APR. 18.00 16.63 76.40 7t.,.06 MAY 40.80 38.36 81.10 80.49 .JUNE 58.90 56.46 57.40 5.~. 79 JULY 66.90 64.46 34.10 33.49 AUG. 67.50 65.06 21.20 20.59 SEPT. 43.Q)0 40.56 87.10 86.49 OCT 31.10 30.42 126.40 12,~. 23 NOV'. 29.6el 28.92 118.40 118.23 DEC. 32.61Zl 31.92 98.30 98. 13 TOT(-\L 4i:33. i .. e, 465.70 (196. 7~ ~··192 .. ::30

a Source: Paint Flaw Stud~, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner

and A'::isociates Gray Rocks Operat ion Stu1.iy GRGFili9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CR~Eh PROJECT AT SELECTED SITES (WITH 11,25(2) AC-FT REPLACEMENT WATER AT STATE LIt'-lE)

100(2) AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD·JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1950 JAN. 32.6121 31.93 95.00 94.82 FEP.• 31. 1121 3121.43 11212.8121 102.62 MAR. 31.4121 30.73 100.2121 1(2)0.02 APR. 15.7121 14.36 71.80 71.44 MAY. 32. 70 30.31 56.60 55.95 JUNE 57.40 55.01 33.80 33. 15 .JULY 68.2Ql 65.81 58.40 57. Tj AUG. 57.213 54.81 68.30 67.65

SEPT. 49.90 47.51 119.80 1 •.L 0E • 15 OCT. 33.40 32.73 131.50 131.32 NOV. 29.20 28.53 113.IZH?J 112.82 DEC. 34.20 33.53 115.70 115.52 TOTAL 473.0121 4~j5. 70 1066.90 1~62.2r:

1951 JAN. 29.40 28.78 92.80 92.60 FEB. 27.8121 27.18 92.40 92.20 t1AR. 22.80 22.18 84.50 84.30 APR. 19.10 17.87 73.80 73.40 MAY 31.70 29.50 63.70 62.98 \..TUNE 36.50 34.30 103.40 102.68 .JULY 56.50 54.30 86. 1 Ql 85.38 AUG. 61.30 59. 10 52.70 51.98 SEPT. 39.90 37.70 161. 50 160. 78 OCT. 47.90 47.28 146.70 146.50 NOV. 38.30 37.68 127.20 127 .00 DEC. 26. 10 25.48 88.80 88.60 TOTAL 437.30 421.40 1173.60 1168.':+0

1952 .JAN. 24.20 23.38 89.20 88.99 FEB. 23.60 22.78 91.40 9L 19 MAR. 28. :.:)0 27.68 114.30 114.09 APR. 49.15 47.50 114.10 113.68 MAY 112.20 109.26 132.30 131.55 ·JUNE 189.00 186.06 180.30 179.55 .JULY 69.30 66.36 47.70 46.9'j AUG. 69.70 66.76 38.60 37.85 SEPT. :j2.7(2) 49.76 72.9(2) 72. 1 :5 <)CT 38.00 37.18 128.70 128.49 NOV. 32.~(2) 31. 18 127.80 :27.59 DEC. 33.80 32.98 119.90 119.-::.9 TOT,6.L 722. l0 700. ::30 12:":~7. 20 i. :.?31 • 8vl a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980.

b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

101210 AC-FT UNITS a b a l"J RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD·JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1953 .JAN. 32.10 31. 53 104.90 1\04.7 i r FEP.• 27.70 27.13 91.70 91.54 MAR. 29.40 28.83 101.90 11211. 7 L'r APR. 19.50 18.36 83.60 83.28 MAY. 27.70 25.66 56.40 55.83 JUNE 41.1121 39.06 59.10 58.53 .JULY 65.90 63.86 31.00 30.43 AUG. 51.60 49.56 83.40 82.83 SEPT. 42.00 39.96 48.90 48.33 OCT. 26.70 26.13 95.90 95.74 NOV. 22.70 22.13 97.60 97.44 DEC. 20.6121 20.03 87.40 87.24 TOTAL 407.20 392.40 941. 80 937.7V)

1954 JAN. 17.50 17.14 79.20 79.10 FEE. . 14.20 13.84 74.20 74.1v) MAR. 15.30 14.94 97.40 97.3121 APR. 11. 10 10.38 63.30 63.09 MAY 11.20 9.92 50.50 50.13 .jUNE 22.80 21.52 26.60 26.23 JULY 50.40 49. 12 10.4121 10.03 AUG. 48.40 47. 12 19.40 19.03 SEPT. 32.30 31.02 22.20 21.83 OCT. 9.40 9.04 53.50 53.4I7J NOV. 15.90 15.54 70.00 69.90 DEC. 13. ~jl2l 13.14 72.3~ 72. 2~0 TOTAL 262.0121 252.70 624.00 r~21. 30

1955 JAN. 13.20 12.90 60.50 60.39 FEP.• 10.90 10 •.b0 60.20 .b0.09 MAR. 13.50 13.20 78.20 78.0'? APR. 14.60 14.00 66.20 65.98 ' ..,. MAY 22. ~)(Z) 21.42 47.50 Lf-t • 1il.l .JUNE 37.7121 36.62 53.10 52.70 .JULY 53.90 52.82 33.70 33.3"1 AUG. 43.90 42.82 12.70 12.30 SEPT. 32. :;~0 31.12 29.90 29. 5~1 !)CT 15. 10 14.80 70.10 6"=1 • 99 NOV. 17. :?0 16.90 74.80 74.6'i DEC. 17.00 16.70 74.70 74.59 TOTAL 219.70 211.90 661.60 ,SS8.7(0 a Source: Point Flow Study, North Platte River, Wwaming - Nebraska, Water and Power Resources Service, Jul~ 1980. b Flaw adjustments were made using simulated depletions fram Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOl)T THE CORN CREE'"' PRO.JECT AT SELECTED SITES (WITH 11,25121 AC-FT REPLACEt1ENT WATER AT STATE LINE:'

10121121 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1947 JAN. 30.5121 29.71 94.5121 94.28 FEP.• 26.20 25.41 87.3121 87.08 MAR. 28.20 27.41 94.1121 93.88 APR. 23.6121 22.03 8121.90 BIli.47 MAY. 38.80 36.00 56.50 55. t .. :1 .JUNE 122.90 12121.1121 216.50 215.73 .JULY 74.8121 72.00 159.0121 158.23 AUG. 66.80 64.00 38.90 38.13 SEPT. '+5. 10 42.3121 73.:20 72.43 OCT. 30.30 29.51 123.80 123.58 NOV. 31.2121 3121.41 12121.60 12~. 3t:; DEC. 35.10 34.31 12121.90 120.68 TOTAL 5~j3. 50 533.20 1266.2121 1260 ..::;.0

1948 JAN. 34.7121 33.88 92.70 92.51 FEB. 32.90 32.08 107.80 107.61 MAR. 56.90 56.08 128.7(2) 128.51 APR. 33.00 31.35 94.50 94. 1 L MAY 44.0121 41.136 56.513 55.81 .JUNE 61.2121 58.26 95. tl2l 94.41 ·JULY 77.113 74.16 77.90 77.21 AUG. 81.90 78.96 58. :;:-~0 57.51 c· 1 c· ~ SEPT. 58.4121 55.46 82.60 '-1 .1.,. i J. OCT. 38.7121 37.88 126.80 126.61. NOV. 41.3121 40.48 119.80 ::'19.61 DEC. 36.70 35.88 96.40 96.2'L TOTAL 596.80 575.50 1137.00 1132.;00

1949 JAN. 31.7121 3121.98 7121.20 70.t!H FEP.• 33.70 32.98 110.2121 110.1211 MAR. 28.3121 27.58 123.~12I 122.81 APR. 26.7121 25.27 91. S0 91. : 1 MAY 33.0121 30.45 87.60 86. 91 .JUNE 72.60 70.05 118.50 117.81 JULY 71.7121 69.15 43.80 43. 1 t AUG. 70.00 67.45 47.70 47.01 SEPT. 42.7121 4121.15 90. ~jlZl 89.8°t OCT 34.7121 33.98 126.70 126.51

~ ~ .,":' NOV. :;:-~8. 5121 27.78 112.:-30 J. .t.';"'11 11 DEC. 31.30 30.58 106.40 106.2: TOTAL 504.90 486.40 1128.40 1123 .. 4(f} a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREE~\ PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LIt'-lE)

1000 AC-FT l)NITS a b .a iJ RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT AD.JUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1956 JAN. 14.90 14.48 72.80 72.70 FEP.• 12.30 11.88 62.70 62.60 MAR. 13.20 12.78 67.20 67.1el APR. 11 .80 10.97 49.60 49.41 MAY . 22.70 21. 21 31.50 31.15 .JUNE 28.50 27.01 15.00 14.65 .JULY 53.30 51.81 52.20 51 . 8Cj AUG. 64.90 63.41 11.50 11. 15 SEPT. 35.70 34.21 15.60 15.2S OCT. 9.20 8.78 48.40 48.30 NOV. 17.60 17.18 79.8e 79.70 DEC. 16.70 16.28 69.70 69.60 TOTAL 300.80 290.00 576.(12) 573.50

1957 .JAN. 12.70 12.16 52.20 52.05 FEP.. 11.60 11.06 67.1e 66.9~ MAR. 12.20 11.66 66.40 66.25 APR. 12.50 11.43 68.70 68.41 MAY 57.50 55.58 113.312) 112.78 JUNE 30.50 28.58 90.20 89.6fj ·JULY 69.70 ,~7. 78 38.50 37.0.8 AUG. 67.50 65.58 45.40 44.88 SEPT. 38.60 36.68 69.70 ·~9;a 1:3 OCT. 27.00 :26.46 90.60 90.4::1 NOV. 22.40 21.86 88.00 87,,85 DEC. ~::~0. 70 20.16 83. 10 82.9:.1 TOTAL 382.90 369.00 873.20 869.40

1958 .JAN. 18.21Zl 17.67 69.30 69.14 FEE. • 15.70 15. 17 67.00 66.84

MAR. 16.50 15.97 81.50 o·'..J J. • "...;,t+ APR. 20.10 19.03 90.20 89.88 MAY 33.40 31.49 65.90 65.33 .JUNE 25.40 23.49 101. 10 100.53 JULY 62.30 60.39 92.40 91 .. 83 AUG. 72.20 70.29 30.4121 29.83 SEPT. 42. 10 40. 19 59.30 58.73 OCT 28.70 28.17 100.50 100.34 NOV. 23. 10 22.57 89.80 89.64 0"'7 '''':'I?! DEC. 23. 10 22.57 '-1 ( • ~'IU 87.04 TOTAL 380.80 367.0(2) 934 . .'-,0 9](2). 5 ~'1 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, Jul~ 1980. b Flow adjustments were made using simulated depletions from Banner and Associat@s Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVE~ FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

100121 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD·JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1959 JAN. 19.4121 18.88 79.3121 79.17 FEP.• 15.7121 15.18 73.6121 73.47 MAR. 17.2121 16.68 81.1121 80.97 APR. 17.3121 16.26 78.8121 78.54 MAY. 22.6121 2121.75 7121.0121 69.53 .JUNE 28.30 26.45 34.10 33. f~3 .JULY 63.10 61.25 19.70 19.23 AUG. 67.70 65.85 12.0121 11.53 SEPT. 48.1121 46.25 45.2121 44. 7~ OCT. 29.20 28.68 113.70 113.57 NOV. 21.2121 2121.68 87.10 86.97 DEC. 18.7121 18.18 81.80 81. 67 TOTAL 368.5121 355. 1121 776.4121 773. iZH2)

1960 .JAN. 16.012\ 15.54 67.012) 66.90 FEB. 15.70 15.24 70.40 70.30 MAR. 17.90 17.44 93.20 93. 112) APR. 14.80 13.88 65.2121 64.99 MAY 8.4121 6.76 47.90 47.53 .JUNE 32.1121 3121.46 17.6121 17.23 JUL'.." 73.40 71.76 7. 1121 6. 73 AUG. 64.8121 63.16 ~L:::. 10 11.73 SEPT. 35.4121 33.76 22.10 21. [...j OCT. 16.60 16.14 ,~5 • ~7~0 ,:='5. 10 ""7'-:, "7r71 NOV. 17.00 16.54 t ~. '-I4J 72.20 DEC. 17.10 16.64 65.3121 65.2~ TOTAL 329.20 317.30 61215.4121 602.70

"C .-:.Q 1961 JAN. 15.50 15.09 65.40 O.J.":"'1 FEP.• 12.00 11.59 64.50 64.39 MAR. 13.1121 12.69 73. 1121 72.99 APR. 13.70 12.89 63.2~ 62.98 MAY 12.112l 1121.65 70.5121 70.1l ,JUNE 12.30 10.85 27.20 26.81 .JULY 75.80 74.35 11.00 10.61 AUG. 48.20 46.75 19.3121 18.91

"7'"1 ,-:,~ SEPT. 34.7121 ".j"";;. ":"...1 28.5121 28. 11 OCT 19.3121 18.89 79.00 78.89 NOV. 18.31Z1 17.89 77.C'l12l 76.89 DEC. 17.0121 16.59 70.00 69.89 TOTAL 292.00 281.50 648. 70 645. 9~J

3. Source: Point Flow StLtO!::l, N'::Jrth Platte River, WYo::J!'ni ng - Nebra.'5ka. ~. Wat~r and POI.!Jer Resources Service, .Ju.1.y 19812l. b Flaw adju.-5tments IlJere made using s i mu 1.3. ted depletiDns f'r~om :Ba,nner and Associates Gray Rock'5 Op~ratian Study GRGFC'l9. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,25~ AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD.JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1962 JAN. 11. 10 10.56 58.60 58.4:5 FEB. 14.10 13.56 57.90 57.75 MAR. 15.80 15.26 73.80 73.65 APR. 17.30 16.23 57.90 57.59 MAY. 43.00 41.08 62.70 62. is JUNE 42.50 40.58 132.40 131.85 .JULY 59.30 57.38 105.20 104. 6~5 AUG. 68.90 66.98 38.410 37.85 SEPT. 40.60 38.68 58.50 57.95 OCT. 30.90 30.36 108.60 108.45

NOV. :::-~0. 80 20.26 87.80 :37 D ,SS DEC. 18.80 18.26 74.50 74.35 TOTAL 383.10 369.20 916.30 912.30

""7 ='4- 1963 JAN. 14.20 13.67 63.70 o·~. _·u FEE,. 16.t0 15.57 89.20 8C?'.06 MAR. 19.30 18.77 95.10 94. ':;>6 APR. 15.60 14.54 76.00 75. 7:::-~ MAY 41.60 39.71 35.40 34.90 .jUNE 22.50 20.61 73.60 73. 1 III JULY 78.60 76.71 9.00 8.50 AUG. 67.50 65.61 17.60 17. 10 SEPT. 41.20 39.31 71.90 71.40 OCT. 25.80 25.27 112.5~ 112.36 NOV. 19.60 19.07 93. L~!2) 93.26 DEC. 16."20 15.67 76.3~ i b. 16 TOTAL 378.20 364.50 813.70 810.10

1964 .JAN. 14.80 14.26 116.90 116. 7:~ FEE. • 13.90 13.36 101.40 101.28 MAR. 15.00 14.46 1(2)2.50 102.3f3 APR. 170.10 169.03 127.70 127.47 MAY 32.30 30.38 77.50 77.09 , ...... 0 .JUNE 42.00 40.08 67.80 b I.·..:J! JULY 76.0~ 74.08 31.50 31.09 AUG. 71. 51?) 69.58 24.00 23.59 -t 1-'1 SEPT. 37.00 35.08 50.610 50. 1 ;' OCT 25.60 25.06 90.50 90.38 NOV. 1.9.90 19.36 107. 10 1.06.98 DEC. 17.40 16.86 93.50 93.38 TOTAL_ 382.50 368.60 685.20 682. o,?~')

-3. Source: P,:> i n t Flol.l' Study, North Platte Ri"/er, ~.J!::Iom i ng - Nebrao:;ka., Watl?r .and POlller Resources Ser-ovir:e, .Ju.I y 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Racks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

1001ll AC-FT UNITS a b a h RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1965 JAN. 16.30 15.62 77. 7 III 77.51 FEB. 14. 1 III 13.42 65.60 65.41 MAR. 14.00 13.32 58. 2 III 58.01. APR. 11.90 11ll.54 59.80 59.43 MAY. 66. 9 III 64.47 61.70 61 • 0L~ JUNE 112.90 110.47 21ll3.8iZl 203.14 ,JULY 60.00 57.57 1t06.80 1. 06. ll~ AUG. 67.20 64.77 46.40 45.74 SEPT. 41.20 38.77 98. 1 III 97.44 OCT. 32.80 32.12 125.40 125.21 NOV. :23.00 22.32 90.90 90.71 DEC. 20.60 19.92 94. 6 III 94.41 TOTAL 480.90 463.30 1089.00 1084.20

1966 JAN. 17.30 16.75 73.90 73.75 FEB. 13.60 13.05 73.30 73. 15 MAR. 17.20 16.65 88.1210 87.85 APR. 30.40 29.29 84.70 84.40 MAY 39.10 37.13 37.50 36.96 JUNE 41ll.50 38.53 54.70 54.16 JULY 75.3tzl 73.33 29.60 29.06 AUG. 58.90 56.93 53.70 53.16 SEPT. 39.70 37.73 99.80 99.26 OCT. 25. 10 24.55 111.00 110.85 NO'';. 19.60 19.05 97.40 97.25 DEC. 17.10 16.55 76.50 76.35 TOTAL 393.80 379.50 880.10 876.20

1967 JAN. 14.50 13.94 72.80 72.6/+ FEB. 11.40 10.84 64.20 64.04 MAR. 11.80 11.24 68.50 68.34 APR. 10.4121 9.28 51.10 50.78 MAY 21.90 19.90 57. lei 56.53 JUNE 77.9(2) 75.90 167.00 166.43 ,JULY 68.20 66.20 83.30 82. T3 AUG. 69.70 67.70 28.50 27.93 SEPT. 43.90 41.90 73.30 72.1'3 OCT 26.20 25.64 97.20 97.04 l NOV. 23.00 22.44 91.6e! 91 II 4 r DEC. 21.00 20.44 70.80 70.64 TOTAL 399.90 385.40 925.40 921.30 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREE~\ PROJECT AT SELECTED SITES (WITH 11 ~ 250 AC-FT REPLACEMENT WATER AT STATE LINE)

112100 AC-FT UNITS a b a l.! RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1968 JAN. 17.50 16.82 72.80 72.63 FEB. 16.80 16.12 76.10 75.93 MAR. :22.20 21.52 72.20 72.03 APR. 42.50 41.13 11210.20 99.86 MAY. 45.50 43.06 95.30 94.69 JUNE 98.70 96.26 11,~. 10 115.49 ,JULY 74.90 72.46 31.80 31. 19 AUG. 57.00 54.56 76.10 75.49 SEPT. 35.30 32.86 82.2121 81.59 OCT. 30.10 29.42 104.80 11214.63 .-•. -, .-,0,"", NOV. 22.90 .::...:.. . ..;,..::,. 94.20 94.~3 DEC. 20.50 19.82 75.00 74.83 TOTAL 483.90 466.20 996.80 992.40

1969 JAN 18.80 18.19 69.50 69.35 FEP,. 16.20 15.59 71.20 71.1215 MAR. 23.70 23.09 88.50 88.35 APR. 43.10 41.89 98.70 98.40 MAY 29.60 27.43 75.60 75.06 JUNE 33.90 31.73 61.30 60.76 JULY 75.70 73.53 23.90 23.36 AUG. 74.30 72.13 20.50 19.96 SEPT. 41.40 39.23 53.60 53.06 OCT. 32.50 31.89 131.9Q) 131.7'5 NOV. 22.10 21.49 111.10 110.95 DEC. 18.30 17.69 86.8121 86.65 TOTAL 429.60 413.90 982.6\(j 888.70

1970 JAN. 16.10 15.75 712).5(0 712).32 FEB. 14.30 13.95 74.6121 74.42 MAR. 15.60 15.25 77.513 77 . 3~~~ APR. 22.60 21.90 89.10 88.74 MAY 55.00 53.74 82.212) 81.5h ,JUNE 129. 10 127.84 153.40 152.76 \JULY 85.20 83.94 59.20 58.56 AUG. 67.40 66.14 35.60 34.9,!J SEPT. 37.70 36.44 73.00 72.36 1 ·~,o .-:'--:' OCT 34.7121 34.35 129.4121 .L ~ / • .&.:-":" NO!J. 25.80 25.45 111.:20 111 . 0:~~ DEC. 21.20 212).85 80.60 80.42 TOTAL 254.70 245.60 1036.30 1.031.7~ a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Power Resources Servi~e, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

1000 AC-FT UNITS a b a !J RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD,JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1971 JAN. 19.80 18.98 79.40 79.05 FEB. 16.70 15.88 73.20 72.85 MAR. 19.80 1.8.98 85.20 84.85 APR. 140.80 139.15 163.10 162.40 MAY. 444.30 441.36 451.50 450.26 JUNE 435.00 432.06 524.20 522.96 .JULY 174.10 171.16 1:35. 10 183.86 AUG. 74.00 71.06 5~.80 49.56 SEPT. 47.50 44.56 108.30 107.06 OCT. 35.3121 34.48 126.30 125.95 NOV. 24.60 23.78 104.• 80 104.45 DEC. 21.3121 20.48 88.60 88.25 TOTAL 1453.20 1431.90 2040.50 2031.50

1972 JAN. 19.40 18.58 73.40 73. 19 FEB. 27.2121 26.38 80.2121 79.99 MAR. 136.60 135.78 180.80 18121.59 APR. 47.6121 45.95 111.80 111.39 MAY 5121.80 47.86 84.80 84.07 JUNE 103.00 10121.06 132.70 131.97 .JULY 88.1121 85. 16 77.00 7'0 ...... -;" , AUG. 67.1121 64.16 58.10 57.37 SEPT. 35.00 ·32.1216 96.30 95.57 OCT. 31.00 30.18 1.\217. (~0 l06.7':;- NOV. 24.20 23.38 108.50 108.29 DEC. 18.00 17. 18 85. 10 84.89 TOTAL 648.0(2) 626.7121 1195.70 1190.40

1973 JAN. 17. (d0 16. 18 85.20 84.81 FEB. 15.70 14.88 72.0121 71.61 MAR.• '22.20 21.38 95.70 95.31 APR. 1(2)6.1121 104.45 149.30 148.52 MAY 384.10 381.16 411.10 409. 71 ·JUNE 415.9121 412.96 439.60 438.21 .JULY 220.60 217.66 205.60 204.21 AUG. 225.40 222.46 208.20 206.81 SEPT. 140.20 137.26 251.liJ0 249.61 OCT 51.20 50.38 164.20 163.81 NO\';. 33.9121 33.08 124.30 123.91. DEC. 26.70 25.88 99.20 98.81 TOTAL 1659.ii)12l 1637.70 23tll5.40 :~~295. 3(0 a Source: Paint Flaw Studs, North Platte River, Wyoming - Nebraska, Water and Power Resources Service, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associates Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEh PROJECT AT SELECTED SITES (WITH 11 ~ 251a AC-FT RE:PLACEMENT WATER AT STATE L It'JE)

1000 AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT ADJUSTED STATE LINE FLOWS LEWELLEN FLOWS

1974 JAN. 26.10 25.28 113.80 113.53 FEB. 23.50 22.68 94.50 94.23 MAR. 258. '+0 25i.58 276.70 276.43 APR. 262.20 260.55 323.10 322.55 MAY. 94.60 91.66 139.70 138.72 JUNE 140.20 137.26 145.30 144.32 JULY 96.90 93.96 58.20 57.22 AUG. 68.10 65. 16 53.40 52.42 SEPT. 37.30 34.36 101.00 HZH2l802 OCT. 33.00 32.18 120.40 120.13 NOV. "23.90 23.08 95.20 94.93 DEC. 21.30 20.48 94.50 94.23 TOTAL 1085.50 1064.20 1615.80 1608.70

1975 JAN. 18.60 17.96 89.90 89.74 FEE. • 15.80 15. 16 81.80 81.64 MAR. 18.10 17.46 76.00 75.84 APR. 25.80 24.52 94.20 93.8::-3 MAY 29.30 27.01 81.80 81.23 .JUNE 50.40 48.11 76.20 75.63 JULY 105.90 103.61 59.70 59.13 AUG. 74.80 72.51 37.50 36893 SEPT. 42.50 40.21 65.10 64.53 OCT. 31.30 30.66 1~7.20 107.04 NOIJ. 22.60 21.96 97.10 96.94- DEC. 20.6(2) 19.96 96.60 96.44- TOTAL 455.70 439.10 936.1Q) 932.00

1976 JAN. 17.90 17.31 93.90 93.75 FEB. 17.00 16.41 85.90 85.75 MAR. 15.50 14.91 73.10 72.95 APR. 18.70 17.53 73. 10 72.813 MAY 33.50 31.4121 71.50 70.96 ·JUNE 40.00 37.90 57.80 57.2,!=, JULY 88.7121 86.6~ 25.:20 24.66 AUG. 71.20 69.10 51.80 51.26 SEPT. 42.90 40.8121 72.30 71. (0 OCT 33.8121 33.21 110.30 110.15 NOV. 19.8121 19.21 88.40 88.25 DEC. 18.70 18.11 85.40 85.25 TOTAL Ld 7. 71Z) L1-1lI2.51/j 808.70 884. :'.30 a Source: Point Flow Study, North Platte River, Wyoming - Nebraska, Water and Pow~r Resources S~ryice, July 1980. b Flow adjustments were made using simulated depletions from Banner and Associat~s Gray Rocks Operation Study GRGF09. NORTH PLATTE RIVER FLOWS WITH AND WITHOUT THE CORN CREEK PROJECT AT SELECTED SITES (WITH 11,250 AC-FT REPLACEMENT WATER AT STATE LINE)

10012) AC-FT UNITS a b a b RECORDED STATE LINE RECORDED LEWELLEN YEAR FLOWS AT ADJUSTED FLOWS AT AD·JUSTED STATE LINE FLOWS LEWELLEN FLOWS

1977 JAN. 15.90 15.41 67.90 67.76 FE:E.• 13.2121 12.71 75.60 75.46 MAR. 13.1121 12.61 75.9121 75.76 APR. 13.90 12.92 71.2121 70.93 MAY. 31.00 29.25 65. :"50 65.0'2 JUNE 37.30 35.55 54.80 54 .. 32 JULY 80.50 78.75 28. ~SIZl 28.02 AUG. 54.90 53. 15 47.20 46.72 SEPT. 36.60 34.85 61.30 60.82 OCT. 21Zl.30 19.81 88.50 88.36 NOV. 16.90 16.41 78 .. 90 78.76 DEC. 16.6121 16.11 73. 10 72.96 TOTAL TjlZl.20 337 .. 50 7B8.40 784.90

a Source: Point Flow Study, North Platte River, Wyoming Water and Power Resources Service, July 1981Zl. b Flow adjustments were made us~ng simulated depletions from Banner and Associat~s Gray Rocks Operation Study GRGFIZl9. APPENDIX C

AGENCY COMMENTS ON THE DRAFT ENVIRONMENTAL ASSESSMENT COMMENTS ON DRAFT EA FOR cerD JULY 10, 1985

CONTENTS

Page 1. Letter from Wyoming State Planning Coordinator 2. Wyoming Recreation Commission 4. Wyoming State Archives, Museums & Historical Dept. 5. Wyoming Water Development Commission 6. Wyoming OEQ--Water Quality Division 7. Wyoming OEQ--Land Quality Division 8. Wyoming State Engineers Office 10. Wyoming Game and Fish Dept. 15. US Bureau of Reclamation 18. US Fish and Wildlife Service--Wyoming Office 2I~ US Fish and Wildlife Service--Nebraska Office 23. US Fish and Wildlife Service--Endangered Species Office 26. National Park Service (Fort Laramie) STATE OF WYOMING OFFICE OF THE GOVERNOR CHEYENNE 82002

ED HERSCHLER GOVERNO~ July 8, 1985

Mr. Mel Eaton Corn Creek Irrigation District Veteran, WY 82243

Dear Mr. Eaton:

The draft environmental assessment for the Corn Creek Irrigation Project has been circulated for state agency review. Copies of agency comments are enclosed for your consideration and use. Several agencies, including the Department of Economic Planning and Development and the Department of Public Lands, had no comments on the draft environmental assessment, but did indicate a desire to be kept informed of the progress in this effort.

We encourage your office to work closely with the pertinent state agencies in addressing any questions and concerns raised in the enclosed comments. Feel free to contact us at 777- 7574 if you need any assistance in arranging meetings with various state agencies or need additional information to finalize the environmental assessment. Thank you for the opportunity to review and comment on this project.

Sincerely, \ D lC'C ~~u:L~ Dick Hartman State Planning Coordinator

DH:lf cc: Michael K. Purcell w/enclosures ~~~~ OF WYOMING

EO HERSCHLER GOVERNOR

WYOMING RECREATION COMMISSION 122 WEST 25TH. HERSCHLER BLDG. CHEYENNE. WYOMING 82002

ALVIN F. BASTRON. P.E. Director 13 June 1985 777-7695

~r. Dick Hartman state Planning Coordinator Wyoming State Clearinghouse Herschler Building Cheyenne, WY 82002 RE: 85-193

Dear ~r. Hartman: Seldom is it a pleasure to read an Environmental Assessment. The Corn Creek Irrigation Project Environmental Assessment prepared by CH2M Hill Consultants of Denver, Colorado is one of those all too rare exceptions. The report is well written with facts presented in a readable and concise manner. The consultants should be complimented for the quality of their work. Thank you for the oppor­ tunity to participate in the review process. The Wyoming Recreation Commission (WRC) feels that this project could have significant impacts on recreation in the region. If public acces~ to the site was guaranteed, if an attractive fishery was developed in the reservoir, and if project development occured along the lines described in the Environmental Assessment, this site could become a magnet for increased recreation use in the region. The preferred site, known as the Teeters site, would be accessible to major travel corridors along Interstate 80, Interstate 25, US 26, and US 85. The site would also be close to the Fort Laramie National Historic Site, which currently attracts substantial numbers of tourists. Alternative water-based recreation resources in the area include the large reservoirs of Glendo, Guernsey, Grayrocks, Hawk Springs, and Deer Creek (planned). Smaller regional reservoirs, more along the lines of the proposed Teeter site reservoir include the Rock Lake, Bump-Sullivan, and Springer (Goshen Hole) reservoirs. This region experiences substantial tourism from other parts of Wyoming (Cheyenne and Casper metropolitan areas), and from out of state visitors. ~ch of the out of state use is from adjacent areas in Nebraska and Colorado. Although the site would not offer the opportunities associated with the larger reservoirs, the location of the site coupled with attractive attributes could draw many users.

A~:~:T;ILCH DAN MADIA MRS. ROBERT FRISBY MARK ANSELMI LARRY BIRLEFFI PO B I ENT VICE PRESIDENT TREASURER . 1630 Elk 51. 929 E. Apache MRS. ELIZABETH FIELD JACK D. OSMOND E. LAWSON SCHWOPE JAMES A. WILLOX F . all Aa 1017 V.ctor.a 2007 NeWlon Ave. Rock Spri""S 82901 Cheyenne 82009 P.O. BOil 684 Boll 122 900 Foyer AYe. 1441 Esterbrook Rd. E"anSton 2930 Sher.dan 82801 Cody 82414 .... Newcastle 82701 Ahon 83110 Chevenne 82001 Douglas 82633 Page 2

The WRC is in agreement with the Assessment's conclusion that there will be few, if any, adverse environmental impacts associated with the project. The southeastern portion of the state does show a need for more water-based recreation opportunities according to the 1985 state Comprehensive Outdoor Recreation Plan (SCaRP). The expectation of the WRC is that a reservoir in the approximate location of. the proposed Corn Creek (Teeters) site would have strong recreation impacts on regional recreation. The WRC would appreciate the oppor­ tunity to comment on future reports dealing with the Corn Creek Irrigation Project. Sincerely,

~Jg~>v Alvin F. Bastron, P.E. Director

AFBITKIlr Ed Herschler Governor Wyoming Stat"l.~ Archives, Museums & Historical Department ROBERT D. BUSH. Ph.D. Barrett Building, Cheyenne, WY 82002 Director 307-177-1013

Julia A. Yelvington Division Head Ar"chives &: Records Mgt. 307-777-7826 June .13, 1985 Mike Mayfield Division Head Museums &: Historic Sites 307-777-7510 William H. Barton Ms. Ann Redman Division Head State Planning Coordinator's Office Historical Research &: .Pu blications Herschler Building 307-777-7518 Cheyenne, Wyoming 82002 Board Members RE: §Corn Creek Irrigation Project (85-193) Ken Richardson Chairman Lander Dear Ms. Redman: Frank Bowron Vice-Chairman As noted in the Environmental Assessment, this project "would con­ Casper sist of a water diversion facility, a river pumping facility, a Lucille C. Dumbrill storage reservoir, and a distribution system" (II-I). The project Newcastle would impact an area close the confluence of the Laramie and North .iII Bruce Hines Gillette Platte Rivers. The authors of the EA are fully aware of the historic Thomas J. Mangan significance of this area and have made provisions for consultations Laramie with both the National Park Service and SHPO. Other areas slated for Eugene Martin construction impacts are further removed from this sensitive zone but Evanston may still contain currently unknown cultural resources. Acknowledging Dave Paulley this possibility, CCID will conduct "required [cultural resource] sur­ Cheyenne veys prior to development" and "protect new finds" (IV-30, IV-31). Jerry Rillahan Worland The Wyoming State Historic Preservation Officer is in agreement with Mary Guthrie the procedures outlined in this EA for cultural resource inventory and 'Cheyenne evaluation. Sincerely,

Thomas E. Marceau Review & Compliance Section Head TEM:klm OF WYOMING ED HERSCHLER GOVERNOR

HERSCHLER BUILDING TELEPHONE: 307-777-7626 CHEYENNE, WYOMING 82002

Michael K. Purcell Walter J. Pilch Administrator Chairman James Noble Vice Chairman William J. Kirven. Jr. Secreta"'; Lewis Freudenthal Kenneth Kennedy J.W. Wes Myers Willard C. Rhoads June 5, 1985 Merl Rissler Nelson E. Wren. Jr.

State Planning Coordinator Attn: Mr. Paul Cleary Wyoming State Clearinghouse Herschler Bldg. Cheyenne, Wyoming 82002

RE: SIN 85-193

Dear Mr. Cleary:

The Water Development CODDD.ission completed a preliminary analysis of the Corn Creek project in May 1983. Based on that study, the CODDD.ission determined that project economics did not justify the investment of additional state funds at that time. The proj ect now has a final reporting date to the legislature of 1990.

The Corn Creek Irrigation District is continuing its activities relating to the project, including preparation of this environmental assessment. These activ­ ities may result in funding for the project from other sources, or in renewed state interest if the economic situation changes.

The assessment accurately describes the project alternatives and proposed configuration. The document, and the proj ect itself, are likely to be chal­ lenged by downstream interests if it appears construction will begin in the near future.

Sincerely, ~~~ Michael K. Purcell Administrator

MKP/sj • OF WYOMING EO HERSCHLER GOVERNOR qj)e/ta"ttment.ol 8n1Ji"tonmental llualitll

Ci)falei- llual';t, fJIJ';f1.';~U;n

HERSCHLER BUILDING CHEYENNE. WYOMING 82002 TELEPHONE 307 777 -7781

------M E M 0 RAN DUM

TO: Robert E. Sundin, Director

FROM: Christian Norman, E.I.T. Engineering Evaluator

DATE: June 5, 1985

SUBJECT: Comments on E.I.S. - Corn Creek Irrigation Project

Environmental Consequences - Water Resources: In determining the net depletion of water from the North Platte River it is assumed that the Corn Creek Irrigation district will return 16,300 ac-ft/year to the North Platte. Why would 32,600 ac-ft be collected only to return 50% back to the river? THE STATE OFWYOMtNG ED HERSCHLER GOVERNOR

LAND QUALITY DIVISION

HEASCHLER BL~G .• THIRD FLOOR TELEPHONE 307·777·7756 CHEYENNE. WYOMING 82002 122 WEST 25TH

MEMORANDUM

TO: Robert E. Sundin, Director FROM: Roger Shaffer, Acting Administrator KS DATE: June 10, 1985

SUBJECT: Request for Comments on Corn Creek Irrigation Project

The Land Quality Division of the Department of Environmental Quality has no specific comments on Corn Creek Irrigation Project.

If any mining of materials is necessary as a part of this plan then the individual performing that mining must contact the Department of Environmental Quality, Land Quality Division.

We thank you for the opportunity to review this document.

RS:ICMO/kv .' " ... ' THE STATE ) '. OF WYOMING ED HERSCHLER e GOVERNOR

HERSCHLER BUILDING CHEYENNE, WYOMING 82002 June 27, 1985

M E M 0 RAN DUM

TO: Paul Cleary, Natural Resources Analyst State Planning Coordinator's Office FROM: Louis E. Allen, Water Resources Engineer ~tP~ SUBJECT: State Identifer No. 85-193; Corn Creek Irrigation Project, Draft EA., CH2M Hill for Corn Creek Irrigation District, May 1985.

We offer the folowing comments and questions on the subject draft EA.

On page I-I, we find a July 24, 1984, date given for the contract between the CCID and Basin Electric Power Cooperative. We question this date.

On page 1-4, we find that the project is economically feasible with a benefit-cost ratio greater than 1.0. We wonder what the actual benefit-cost ratio is estimated to be.

On page 11-7, we find that the Teeters Reservoir would be designed to include storage for the design storm runoff. What is the design storm for this Teeters Reservoir on Cherry Creek? Likewise, for the Glomill - Reservoir on Box Elder Creek, what is the design storm?

On pages IV-4 and IV-5, we question the 50% consumption figure for irrigation applications. We also question the assumption that the return flow occurs in the same month that the water is used. The usual return flow pattern is a delay following the irrigation application. We wonder about the 5,050 acre-foot depletion that would occur primarily in the mid-April through mid-October irrigation season. It seems that this depletion would occur anytime water was pumped from the river, either for irrigation application or storage in the project reservoir. Paul Cleary June 27, 1985 Page 2

Table 6 on page IV-8 needs to have the units specified.

Thank you for the opportunity to review this draft EA. Your referral memorandum is being returned as requested.

LEA/ht cc: George L. Christopulos State Engineer

Gordon W. Fassett Deputy State Engineer

John Shields Interstate Streams Engineer OF WYOMING ED HERSCHLER GOVERNOR

CBame and f¥io,k qJje/ta~/menl

CHEYENNE~ WYOMING 82002 w. DONALD OEXTER June 26, 1985 DIRECTOR EIS 2114.L2 Corn Creek Irrigation Proj. Draft EA prepared by CHM Hill for Corn Creek Irrigation District-SIN 85-193 Mr. Dick Hartman State Planning Coordinator Herschler Bldg. Cheyenne, WY 82002

Attention: Mr. Paul Cleary

Dear Mr. Hartman:

In response to your notification, we have reviewed this DEIS and offer the following comments and information for use in making the final assessment and project plan more complete and accurate in considering impacts to fish and wildlife resources.

Potential effects of this project on our efforts to restore flows in the North Platte River between Glendo and Guernsey Reservoirs represent a major fisheries concern. Our efforts to restore flows were mentioned on page IV-25 and 26; however, the project proposes (page IV-6) delivery of Glendo water on a pre-arranged schedule during May through September due to per­ ceived restrictions on winter releases. The CCID does indicate a willingness (page IV-25) to evaluate the possibility of using winter releases from Glendo Reservoir if current regulations could be modified. We request that CCID support and commit to the use of winter releases from Glendo Reservoir contingent upon modification of current regulations to permit such releases. This statement should be included in the final EA. Winter releases would have a very beneficial effect on the trout fishery (page IV-26) as opposed to the insignificant impact of summer releases (page IV-24), and would result in significant public fishing and recreation bene­ fits.

SPECIFIC COMMENTS IN ORDER OF PAGINATION OF THE DOCUMENT:

1. Page 111-4 Tables 1-5.

Comment: Inclusion of data for the 1983 and 1984 water years is recom­ mended if these data are available.

2. Page 111-14.

Comment: Describes a decline in fishing pressure on Grayrocks Reservoir since 1981. Fishing pressure increased in 1984 and seems to be up again Mr. Dick Hartman June 26, 1985 Page 2 - EIS 2114/L2.

in 1985 in response to development of a good warm water fishery. A creel census was conducted in 1984 by the Game and Fish Department and a report will soon be available.

3. Page IV-14 paragraph 1. This paragraph states that Teeter's dam and Cherry Creek bottom would be revegetated to enhance wildlife. Plantings on the dam would be supplied water through seepage and the riparian areas downstream through seepage and released flows if necessary. Trees and shrubs could be transplanted into this area if necessary.

Comment: Although these are good recommendations, there are no speci­ fics presented (ie., What types of plants will be used? How much area will be set aside? How will water be tied to the success of these plantings?)

4. Page IV-14 paragraph 3. "Shrubs would be planted at the base of the dam. II "The sloping face of the dam and the expanded riparian habitat below the dam would be fenced to exclude grazing cattle."

Comment: What species and density of shrubs will be planted? How much area will be fenced? More information should be provided.

5. Page IV-IS paragraph 1. "Enhancement of wildlife habitat around the reservoir."

Comment: This is a good recommendation and the Department would be happy to provide assistance. There is no mention, however, of public access to the reservoir and this may mean that the potential for this site as an area to observe, photograph, or hunt wildlife may never be realized.

6. Page IV-IS paragraph~. "Willows and small cottonwoods that might be flooded out by the permanent pool would be transplanted or replaced on district land along the boundaries of the new pool."

Comment: Any riparian and/or wetland vegetation that will be lost to inundation should be replaced in kind. Recommendations as to potential replacement should be based on the acres of each type lost and should be reviewed by Game and Fish personnel. We do concur with the recommen­ dations to revegetate areas disturbed during construction of this proj ec t.

7. Page IV-16 paragraph l. "Construction techniques suggested by Olendorff et. ale (1981) to protect raptors would be used for upgrading the existing powerlines."

Comment: We concur with this recommendation. Mr. Dick Hartman June 26, 1985 Page 3 - EIS 2114/L2.

8. Page IV-16 paragraph l. "The CCID will encourage the landowners within the district to manage some of these areas for wildlife and to plant shelterbelts for reducing wind erosion and increasing wildlife habitat."

Comment: Although this is a good recommendation, there is no guarantee that any of the existing landowners will agree to this or enter into this type of program. Without some guarantee of participation, we doubt that a significant amount of habitat will be created.

9. Page IV-16 paragraph l. "Shelterbelts and field corners would be fenced to exclude cattle and big game animals such as antelope."

Comment: Although this is a good recommendation, there is still no guarantee that landowners will put in shelterbelts and/or sprinkler cor­ ners.

10. Page IV-17 paragraph 1. "The corridor will be reclaimed using native vegetation or seed mixes recommended by the SCS."

Comment: We concur with this recommendation.

11. Page IV-17 paragraph 1. Subject: Antelope movements and fencing after lands are under production.

Comment: We would like to review the fencing plan in order to determine potential impacts to antelope and to make recommendations as to travel corridors.

12. Page IV-17 paragraph 1. Subject: Loss of mammal and bird diversity as a result of going from short-grass prairie to an agricultural monoculture.

Comment: Although shelterbelts and production of sprinkler corners could create wildlife habitat and promote diversity there is no guaran­ tee that these areas will ever be developed.

13. Page IV-18 paragraph 1. liThe CCIn Board will encourage landowners within the district to allow access for upland game bird hunting."

Comment: We would concur with this recommendation. It must be assumed, however, that no access will be provided if no agreements are worked out before construction begins.

14. Page IV-18 paragraph 1. Subject: Enhancement for waterfowl.

Comment: Although the Teeter's reservoir will provide some waterfowl habitat, its value will be greatly reduced with no minimum pool pro- Mr. Dick Hartman June 26, 1985 Page 4 - EIS 2114/L2.

vided. The new ponds to be created may provide some valuable habitat but this will be largely dependent upon their size and permanence.

15. Page IV-1S paragraph~. Subject: Depredation to crops by deer and antelope~

Comment: Although fencing of sprinkler circles would help to eliminate this problem, there is no guarantee that landowners would agree to fence these lands or whether it is economically feasible to fence them. Since this is the case, the depredation problem is still a very real one.

16. Page IV-IS paragraph 1. Subject: Prairie Dog Towns.

Comment: All prairie dog towns potentially affected by the project should be searched. These searches are to be conducted by qualified personnel.

17. Page IV-IS paragraph 1. Subject: Areas to be set aside to be managed for wildlife.

Comment: There appears to be no incentive for landowners in this area to set aside areas for wildlife management. In addition, the Wyoming Game and Fish would probably not want to own these parcels because of the management cost involved. This is a voluntary program and no specific parcels have been suggested.

IS. Page IV-23 paragraph 1, last sentence.

Comment: Last sentence, first paragraph, we suggest changing could to would.

19. Page IV-27. Mentions that no plans are considered at this time for a fishery in Teeters Reservoir. Mention was made on page 11-12 that the reservoir could be sized to provide a minimum pool if deemed desirable in the final design.

Comment: Feasibility of this alternative to provide a fishery should be evaluated in final design if the project receives state or federal funds. We request that CCID commit to development of a public fishery at Teeters Reservoir if state or federal funds are used and if this alternative is determined to be feasible and desirable and in the public interest.

20. Other:

a. Administrative access should be provided to all lands set aside for mitigation and/or enhancement. Mr. Dick Hartman June 26, 1985 Page 5 - EIS 2114/L2.

b. Although it is probably impossible to ensure public access to most project lands, we recommend providing public access to the reservoir area and to any lands set aside specifically for wildlife management.

c. As mentioned several times, many of the recommendations are vague and dependent upon voluntary cooperation with district owners. We suggest recommendations be more specific and cooperators identified before the project is built to identify areas where wildlife habitat improvements might be possible.

d. The Game and Fish Department 1983 Level III Report ~ Potential Fishery Impacts, Corn Creek Irrigation Project, submitted to the Water Development Commission is cited by the EA. This document contains detailed documentation of our project analysis and support for our major recommendations.

Please forward these comments to the appropriate state and local offi­ cials and contact us if we may be of further help. ;r;:~ FRANCIS PETERA ASSISTANT DIRECTOR OPERATIONS

FP :HBM: sse cc: Game Div. Fish Div. United States Department of the Interior BUREAU OF RECLAMATION REGIONAL OFFICE. LOWER MISSOURI REGION BUILDING 20. DENVER FEDERAL CENTER P.O. BOX 25247 DENVER. COLORADO 80225 IN REPLY REFER TO: LM-150 JUL 2··· 1985 Mr. Mel Eaton Corn Creek Irrigation District Veteran WY 82243 Dear Mr. Eaton: At your request, both the North Platte Projects Office and the Lower Missouri Regional Office have reviewed the Draft Environmental Assessment for the Corn Creek Irrigation Project. We have two general comments dealing with the overall document. First, a number of conclusions concerning the cumulative impacts of water depletions are stated in the text, but the hydrology appendix is not attached for reader review. Secondly, no mention is made whatsoever of the need for a 404 permit under the Clean Water Act. Both of these deficiencies should be clarified prior to finalizing the document. Specific comments are listed below: 1. We believe that the environmental assessment should address the effect that the 10,000 acre-feet of water taken from Glendo Reservoir will have when it is added to the total amount of water that has been sold from the reservoir. We are of the opinion that the cumulative effect may be greater than the effect of the sale of just 10,000 acre-feet of water. 2. Page 1-3, second paragraph - The Laramie River is cited as a possible source of water, but is never again addressed in the environmental assessment. The direct flow rights from the Laramie River and resultant effects should either be addressed further or dropped completely. 3. Page 1-4, last paragraph, 4th line - There is a typographical error in the amount of acres shown. 4. Table 4 - This table represents the flows in the river as natural flows when in fact the figures shown represent releases of stored water to meet irrigation demands and to evacuate excess flood flows. 5. The hydrology cited in Chapter III appears to analyze only 3 years; a longer period of record should be analyzed to include both a series of dry and a series of above normal water years. 6. Page 111-1, last paragraph, 4th line - The temperatures shown are wrong. 7. Page 111-10, first line - This statement should probably say no plants within the project areas, as there are threatened and endangered plants within the State of Wyoming. 8. Page 111-13, first paragraph - Please clarify what is meant by minimum reservoir storage and normal minimum pool. Glendo Reservoir does not have a minimum pool requirement. 9. Page 111-16, first paragraph - Should use 1980 Census 'Bureau data. 10. Page III-3D, first full paragraph, 5th line - Should be the Wyoming State Historic Preservation Officer. 11. Chapter IV - In the discussion of water resources the depletion is stated as 5,050 acre-feet on page IV-4 and 21,350 acre-feet on page IV-7, thus contradicting the conclusions throughout. The depletions are stated as considering a 50 percent return flow and that return flows occur in the same month the diversion occurs; we question whether 50 percent is a reasonable return flow rate with sprinkler irrigation. Additionally, we find no information to support that 50 percent of the total diversion will return to the North Platte River as surface flows. A lag time on return flows should also be used in determining the effect. In order to protect the return flows from diversion or groundwater pumping prior to their reaching the North Platte, it will be necessary to institute some means of control or acknowledge loss of these flows as a result of Corn Creek's diversion. The report also fails to address the effects on the North Platte River between the point of diversion and the point where return flows, if any, reenter the North Platte River as surface flows divertible by other water right appropriators. The report also does not address transportation losses from Glendo or Grayrocks to the point of diversion, nor does the report acknowledge installation of necessary gaging stations above and below the Corn Creek diversion. In order to adequately address the effects of the Corn Creek diversion, the depletions immediately below the diversion, between the point of diversion and point of return flows and downstream it will be necessary to ascertain the point the Missouri Basin Power Project will supplement the Platte River flows with the stated 11,250 acre-feet and on what schedule. In the absence of such information, the effect of Corn Creek's stream depletions above the point where supplementation occurs must be recognized as a depletion inclusive of the 11,250 acre-feet and the environmental and water right effects which result should be addressed. 12. Page IV-2, second paragraph - Earthquakes have been experienced in this area and seismic considerations need to be addressed in the design of the dam. 13. Page IV-3 - Many statements are made concerning methods of cultivation, irrigation, and other practices to minimize erosion. We are not aware of any authority for the district to enforce these methods and we, therefore, think that the effects of conventional cultivation should be addressed. 14. Page IV-22, first line - Typographical error in whooping crane. 15. Page IV-23, last line - The flows in the North Platte River through this stretch greatly exceed 1,000 cubic feet per second. We would suggest you evaluate historic flow data and revise accordingly. 16. Page IV-28, second full paragraph, 7th line - Typographical error in evaluation, should probably be "valuations. 1I

2 17. We would like to see the assessment evaluate the possible problems concerning the inundation and exposure of 800 acres of land because of the annual fluctuation of Teeters Reservoir. Considering the problems we have with weeds at Glendo, we think that this question should be addressed. 18. The Glendo and Guernsey facilities are not currently physically capable of supplying water to the proposed diversion during the winter months. If this is to be addressed, you should consider the costs of physically modifying these structures to allow the proposed operation. We think that the proposal outlined in Chapter II is partially based on the assumption that Glendo water will be released throughout the winter. Sincerely yours,

./-) /~~., a~~' .~ ~Eggen .. 7 Regional Environmental Officer

3 UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE

Fede~i~lgg~T~~n~;r~~g~s3035 316 North 26th Street IN REPLY REFER TO: Billings, Montana 59101-1396

ES July 1, 1985

Mr. Mel Eaton Corn Creek Irrigation District Veteran, Wyoming 82243 Dear Mr. Eaton:

This responds to your May 22, 1985, request for our informal review and comments on the draft environmental assessment (EA) for the Corn Creek Irrigation District's (CeID) project in southeastern Wyoming.

In reviewing the EA, we have assumed that the Bureau of Reclamation (BR) ~ill consider making water available to the project from Glendo Reservoir and the BR will be the "lead" federal agency for compliance with applicable federal environmental laws. This office is providing comments for the U.S. Fish and Wildlife Service (FWS) Ecological Services Offices in the states of Wyoming and Nebraska and the Office of Endangered Species in Helena, Mbntana. The fol'o~ing comments are organized into fish and wildlife issues in 1) Wyoming, 2) Nebraska and 3) threatened and endangered species, both states.

Wyoming The mitigation plan proposed in the EA needs elaboration and should be further coordinated with the FWS and the Wyoming and Nebraska game and fish departments in accordance with provisions of the Fish and Wildlife Coordination Act (16 USC 661, et. seq.). The primary mitigation concern should be for loss of habitats, particularly riparian and wetland, at Teeters Reservoir and either the North Platte River diversion dam or infiltration galley. The impacts to these habitats also need to be further quantified in the EA. we are also concerned about cumulative project impacts on riparian vegetation and associated wildlife due to alteration of stream flows along the Platte River, when combined with other ongoing and proposed water-projects in the area. The riparian plant community ;s greatly dependent upon overbank flooding for the deposition of sediment and nutrients for regeneration, establishment, and maintenance. Cessation of spring flooding and natural channel movement has curtailed the formation of habitat necessary for the establishment of cottonwoods and willows (exposed alluvial sediments with high water table). It is certain that with the anticipated continuing demand upon scarce unappropriated flows, riparian habitat along the North Platte River will continue to degrade, and wildlife populations will decline accordingly. The possible winter releases of Glendo water (10,100 ac.ft.) to the CCID present an opportunity to restore the North Platte River fishery between Glendo Dam and Guernsey Reservoir. we strongly support the use of winter releases from Glendo Reservoir and would welcome the opportunity to work with the district and other water users to achieve modification of current operations to permit such releases.

We would also like to work closely with the district to assist in implementing the wildlife habitat mitigation features to increase wildlife diversity within the agricultural section of the project. As previously indicated, the impacts of the project need to be further quantified in the EA. Additional data needs include: 1) Tabulated or mapped data delineating and quantifying vegetative cover to be disturbed or inundated by Teeters Reservoir, and either the North Platte River diversion dam or infiltration galley; 2) Water diversion rates, timing of withdrawals, and mean annual yield of the direct flow diversion water right from the Laramie River; 3) A hydrograph showing monthly high, low and mean flows (in cubic feet per second) from 1960-1983 for conditions "with the project" compared to IIwithout project II for the following stream areas: - flows at the mouth of the Laramie River (below the diversion) - North Platte River immediately below the mouth of the Laramie River Some specific comments follow and are related to the referenced pages in the EA. 1-3 paragraph 2. The amount and timing of direct flow withdrawals from the Laramie River should be elaborated upon. These withdrawals would reduce Platte River flows and could have a significant affect on downstream fisheries, wildlife, and riparian vegetation. IV-1 paragraph 3. Riparian vegetation flooded by Teeters Reservoir should be mitigated lIin kind". A mitigation plan needs to be developed and fully coordinated with the FWS and the Wyoming Game and Fish Department (WGFD). Prior to the development of the plan, we need to know the acreages to be flooded, by habitat type.

2 IV-4 paragraph 3. The 50 percent return flo~ prediction appears unrealistic for an enclosed pipe delivery system and sprinkler application system situated in a semiarid climate; thus the actual depletion (5,050 ac.ft.) to the Platte River system may be much greater. It appears the return flow prediction should be based on studies conducted on similar irrigation systems for this climate. IV-6 paragraph 1. It is impossible to assess the affects on the Platte system of the 11,250 ac.ft. of replacement water from the Mnssouri Basin Power Project (MSPP) unless the location and timing of releases are kno~n. We recommend that the EA address this item in more detail. IV-14 paragraph 2. In order to determine if the habitat to be inundated is adequately mitigated, the plan should specify project operation and maintenance (0 and M) responsibilities. The plan should also be as specific as possible concerning the types of vegetation to be planted, planting densities, target acreages, and fencing needs. The EA should commit to subsequent negotiation of more specific acreages and locations of plantings and of fencing. IV-IS paragraph 2 and 3. Same comment as preceding one. The EA should specify the acreage to be impacted, by habitat type, for each diversion alternative. IV-16 paragraph 2. Managing field borders and corners for wildlife and planting shelterbelts is an excellent concept. However, for the concept to function as envisioned, the mitigation plan, fully coordinated with the RWS and WGFD, and showing acreages, plant species and densities, and fencing, needs to be developed, as per previous comments. IV-17 paragraph 3. As with the preceding comments, once again a specific mitigation plan needs to be formulated and coordinated with appropriate agencies before the benefits can be realized. IV-IS paragraph 3. The location and number of the "shallow temporary ponds" should be specified and coordinated with WGFD and FWS. IV-19 paragraph 2. The preservation of short grass prairie and its associated ~ildlife is a sound idea. Like with the previous mitigation proposals, a specific mitigation plan is needed. IV-25 paragraph 3. One of the most positive potential environmental effects of the Corn Creek project would be restoring winter flows below Glendo Reservoir, and we encourage all involved parties to pursue this goal. Members of the Glendo to Guernsey instream flow task force have been receptive to the idea of winter flows if these can be accomplished so that injury to participating members would not result.

3 IV-27 paragraph 2. Teeters Reservoir presents an opportunity to provide fishing and recreation if a minimum pool is maintained and public access ;s provided. We strongly endorse these project features. In addition, when cost benefit analyses are performed, these benefits may help justify the expenditure of any public funds on the project Questions and discussions concerning these Wyoming wildlife comments and concerns should be directed to our Ecological Services Office in Cheyenne, Wyoming. They can be reached at: 2120 Capitol Avenue, Room 7010 Cheyenne, Wyoming 82001 Phone (307) 772-2374

Nebraska The EA should also analyze any possible project impacts to the following Nebraska fish and wildlife resources. (1) Inland Lakes (including Lakes Alice, Minatare, Winters Creek and a small satellite wetland below Lake Alice) - These lakes provide quality fishing and some are components of the North Platte National Wildlife Refuge. The refuge is managed primarily for ~aterfowl.

{2) North Platte River above Lake MCConaughy - This river segment in Nebraska supports a good fishery in many areas and provides the migratory path to small tributary streams in which a migratory strain of trout from Lake McConaughy spawn. Additionally, Nebraska administers a statutory waterfowl refuge along the river in Garden County.

(3) Tributary Trout Streams - These streams provide trophy trout fishing and trout spawning habitat. They originate on the north side of the North Platte River from the Wyoming-Nebraska state line to near Bridgeport, Nebraska. MUch of the flow in these streams is derived from seepage of irrigation water extracted from the North Platte River. (4) Lake MCConaughy - This lake supports one of Nebraska's finest sport fisheries, including trophy trout. Gizzard shad are the primary forage fish that sustain this fishery. During some summers, trout habitat is very limited due to low reservoir water levels. Lake levels are also low enough during some winters to cause heavy gizzard shad mortality.

4 (5) Platte River between Lexington and Chapman, Nebraska - This river reach is extremely valuable during migration to about 70 to 90 percent of the entire mid-continent populations of sandhill cranes and white-fronted geese. At least one million other waterfowl use the river during migration. In order to assess the project's potential impacts on Nebraska's fish and wildlife resources, the follo~ing information is needed. Annual and monthly projections for each year from 1941 to 1983 for conditions "with the project," compared to "without the project II for: - Operating levels of Lake Alice and Lake Minatare - North Platte River flo~s at Lewellen, Nebraska - Stream flows for Red Willow and Ninemile Creeks - Operating levels for Lake MtConaughy, and - 'Platte River flo~s at Overton and Grand Island, Nebraska. Critical elements that need to be considered in providing the aforementioned data are water conveyance losses, amount and location of return flows, consumptive use, MBPP replacement water, and agreements with downstream interests (such as with Central Nebraska Public Power and Irrigation District in the operation of Lake McConaughy). The discussion on the absorption or masking of depletions by Lake MtConaughy should also be more specific. On the basis of the information available, it appears to us that estimates of conveyance losses and return flows.are high. Estimates of consumptive use seem to be low. It is unclear whether the MBPP replacement water will constitute an additional consumptive use to which this water has not been subjected before. The EA should state whether any agreements or discussions have occurred with downstream interests and the progress to date regarding these replacement waters. Issues pertaining to the previously described waterfowl, sandhill crane, and sport fishery resources in Nebraska cannot be adequately addressed until the information requested above is provided. Some of the information needs are at least partially covered in Grayrocks Reservoir documents. We suggest that applicable information from those documents be provided in a more complete form as part of the Corn Creek EA. We also realize, however, that some of the Nebraska resources, such as the Inland Lake and tributary trout streams, may not be impacted. We believe the EA should address these resources, however, at least to the extent of explaining why no impacts are predicted. The foregoing Nebraska fish and wildlife comments were provided by and correspondence or questions concerning these should be directed to our Ecological Services Office in Grand Island, Nebraska. They can be reached at:

5 1811 West 2nd Street, Room 430 Grand Island, Nebraska 68801 Phone (308) 381-5571

Endangered Species The final EA should clearly state the Bureau of Reclamation's (BR) IImay affect" or "no affect" determination for each listed threatened or endangered (TIE) species. In addition, cumulative impacts from other federal, state, and private projects (such as the Deer Creek Reservoir, and the Seminoe enlargement project) need to be included in BR's evaluation to determine may affect or no affect. If no affect determinations are made that are dependent upon agreements or other commitments, or on specific mitigation measures, the final EA should identify whether the responsible agency, project sponsor, or project operator has committed to accomplish such measures. For example, the draft EA discusses changes in project operations at MCConaughy Lake that may offset Corn Creek Irrigation Project depletions. However, there is no mention as to whether the MCConaughy Lake project operator has committed to such operational changes. The BR requested a species list for the project on April 26, 1984. Our Endangered Species (SE) Field Office in Helena, Montana provided the BR with a May 1, 1984, list of TIE species that included the bald eagle (Haliaeetus leucocephalue), peregrine falcon (Flaco peregrinus), black­ footed ferret (MUstela niqripes), and whooping crane (Grus americanus). Pursuant to Section 7(c) of the Endangered Species Act of 1973, as amended (ESA), if the federal agency (in this case BR) has not completed their biological assessment within 180 days, the agency should verify andlor update the subject species list with the RWS. Two species that may be present in the area of influence of the project have been listed or proposed for TIE status since issuance of the May 1, 1984, species list. The interior population of the least tern (Sterna antillarum), herein referred to as the interior least tern, was listed as an endangered species (effective June 27, 1985) throughout the Mississippi River Basin north of Baton Rouge, Louisiana. The PWS published a proposed rule on November 8, 1984, to list the piping plover (Charadrius melodus) as a threatened species in the northern plains. Pursuant to Section 4 (b)(6) of the ESA, the RWS must determine and publish a final rule on the proposal to list the piping plover by November 8, 1985. By copy of this letter we are notifying BR of this update of the original species list. The least tern and piping plover are both present in Nebraska along Platte River sandbars and beaches downstream from the project. Alteration of Platte River flows due to irrigation water depletions and channelization has led to the elimination of scouring of sandbars by high water, allowing plant succession and the formation of dense

6 vegetation, and thus making islands and sandbars unsuitable for nesting for either species. Project related impacts to both of these species need to be addressed. The final EA should include a determination of may affect or no affect for the interior least tern. Pursuant to Section 7(a)(4) of the ESA, if the BR determines that the piping plover may be jeopardized, the BR should contact our SE Field Office in Helena to discuss conservation measures for the plover. Since the final rule on the plover is due out in November, we recommend that the BR contact our SE Field Office prior to completion of the final EA to assure that the current status of the plover is addressed in the final EA. As discussed at the December 26, 1984, meeting on the project, water depletions, when considered cumulatively with other Platte River depletions, do have the potential to affect whooping crane habitat in Nebraska, and without further analyses and/or commitments from project operators at Lake MCConaughy to provide necessary flushing flo~s needed to scour habitat, the FWS cannot agree with a no affect to the crane. we support CCIO's intent to protect and transplant cottonwood trees at Teeters Reservoir, the diversion ~eir, and in field borders and corners. Mature cottonwood's will provide habitat for bald eagles in the future. The Laramie River flo~s are important to the maintenance and regeneration of cottonwood trees along the Platte River favored by bald eagles as perch and winter roost sites. Project affects (water depletions) on these cottonwood riparian communities should be analyzed. In addition, the affects of these depletions on fish and wintering waterfowl, an important food item for bald eagles, should be determined. Potential electrocution hazards to bald eagles and other large raptors can be offset by utilizing the raptor proofing techniques presented in Raptor Research Report No.4, as discussed in the draft EA. As previously mentioned, the final EA should reference the CCID's commitment to utilize those techniques. Black-footed ferret surveys are recommended on all pra1r1e dog towns that intersect the project rights-of-way; and all portions of such towns out to one-half mile beyond the right-of-way. Surveys should be conducted and survey reports submitted to our Endangered Species Office for review and concurrence within one year prior to disturbance. Our Endangered Species personnel will provide the BR with guidance on conducting surveys, if necessary. Section 7 correspondence and T/E questions or concerns should be directed to our Endangered Species Office in Helena. They can be reached at:

7 Federal Bldg., U.S. Courthouse 301 South Park P.O. Box 10023 Helena, Montana 59626 Phone (406) 449-5225 We invite CCID to meet with members of the FWS's Cheyenne Office and the WGFD to refine and solidify the mitigation concepts presented in the EA. We also encourage the district and BR to coordinate closely with our Grand Island, Nebraska, Ecological Services Office and the Helena, Montana, Endangered Species Office pertaining to possible downstream impacts to endangered species and wildlife in Nebraska. In addition to the foregoing, we wish to mention establishment of the Platte River Coordination Committee and the associated Platte River Steering Committee, of which you may be aware. In any case, these groups have been formed to resolve issues in the Platte River Basin related to endangered species and other wildlife on the Platte River in Nebraska. For information, we suggest you contact Roger Weidelman of the Bureau of Reclamation in Denver~ CO phone (303) 236-0524.

~ appreciate the opportunity to comment on the draft EA. Sincerely, ~4CI!~ Ecological Services

cc: Assistant Regional Director, USRWS, Denver, Colorado (HR) Assistant Regional Director, USFWS, Denver, Colorado (FA) (Attn: wayne wathen) Project Leader, USPWS, Cheyenne, Wyoming Field Supervisor, USFWS, Grand Island, Nebraska Field Supervisor, USFWS, Helena, Montana (SE) Director, WGFD, Cheyenne, Wyoming Supervisor, WGFD, Pinedale, Wyoming (Attn: Bill Rudd) Director, Nebraska Game and Parks Commission, Lincoln, NE USBR, Denver, CO (Attn: Dick Eggan)

8 United States Department of the Interior NATIONAL PARK SERVICE Fort Laramie National Historic Site Fort Laramie, Wyoming 82212 IN REPLY REFER TO:

June 7, 1985

Mr. Mel Eaton, Project Manager Corn Creek Irrigation District Veteran, WY 82243

Dear Mel:

We have looked over the environmental assessment and have the following comments:

1. As you know, our main concerns are the collection and pumping facilities to be located at the confluence. We are qoping that siting and design will be done to minimize intrusion to the historic scene.

2. In this same view, the electrical distribution system should be designed to not dominate the skyline. It would be very desireable to have underground service to the pumping facility from a point visually away from the area.

3. Several historic trails pass right by the pumping area site (Oregon Pony Express and the California Trail). Certainly, due care should be taken to protect these nationally significant areas.

4. Cultural and Archeological surveys need to be done in advance of all ground disturbing activities.

5. The county roads leading to the pumping facility site are presently in bad shape and the additional construction traffic will make them much worse. Upgrading would be very beneficial before the project is started.

We really appreciate the opportunity to comment on this document and the cooperation you and all personnel connected with Corn Creek Irrigation District have shown.

Don't hesitate to calIon us for assistance or clarification.