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Truckee River Chronology

A Chronological History of Lake Tahoe and the Truckee River and Related Water Issues

The information contained in Part I--Overview of this Truckee River Chronology constitutes a general background and informational description of the Truckee River Basin and its physical, geologic, and hydrologic characteristics and attributes. Part II--Pre-Twentieth Century and Part III--Twentieth Century of this chronology contain a relatively detailed listing by date of some of the more important events associated with the Truckee River Basin, Lake Tahoe and the Lake Tahoe Basin, the Truckee River, various tributaries, storage lakes and reservoirs, water diversions, Pyramid Lake, the Truckee River's interconnection with the Carson River Basin through Derby Dam and the Truckee Canal, and related water supply, water use, water rights, water development, and environmental and water quality issues.

Part I--Overview

Table of Contents

[Click to go directly to each section.]

Introduction

The Truckee River Basin encompasses an area of approximately 3,060 square miles(1) (1,958,400 acres) in the states of California and Nevada. The basin stretches in a generally north by northeast direction from Lake Tahoe, located in the Sierra Nevada Mountains on the border between California and Nevada, to Pyramid Lake, located approximately 50 air miles away in the desert of northwestern Nevada. Connecting this alpine source lake and the basin's desert terminal lake(2) is the 105-mile long Truckee River. Of the basin's total area, approximately 760 square miles (486,400 acres), or almost 25 percent of the basin, lie within the State of California, while the remaining 2,300 square miles (1,472,000 acres), or 75 percent of the basin, lie within the State of Nevada.(3) As a major sub-basin within the Truckee River Basin, the total drainage area of the Lake Tahoe Basin, to include Lake Tahoe and its tributaries, totals approximately 506 square miles (323,840 acres), and comprises 16.5 percent of the Truckee River Basin's total area.(4)

While the greater portion of the Truckee River Basin's surface area, and certainly the majority of its demands for water resources lie within the State of Nevada, most of the precipitation and virtually all of the basin's water storage lie within the State of California.(5) Not surprisingly, this extreme geographic imbalance between the basin's water supplies and its water demands and uses has tended to exacerbate some of the controversies surrounding the rights to, and the uses of, water resources within the Truckee River Basin. Based on the California-Nevada Interstate Compact approved by the California Legislature in September 1970 and the Nevada Legislature in March 1971,(6) Nevada was allocated approximately 90 percent of the Truckee River Basin's waters. By this compact water supplies were also reserved for growth in the Lake Tahoe-Truckee area of California.(7) Total annual diversions from the Lake Tahoe Basin are not to exceed 34,000 acre-feet of which 23,000 acre-feet is allocated to the State of California and 11,000 acre-feet is allocated to the State of Nevada.(8)

Table 1, Nevada Hydrographic Areas in the Truckee River Basin, presents a listing of the Truckee River Basin's hydrographic areas within Nevada, designated as Nevada Hydrographic Region [or Basin] 6, one of 14 hydrographic basins designated within the State of Nevada.(9)

Table 1--Nevada Hydrographic Areas in the Truckee River Basin

Hydrographic Area1
[Nearest Cities]
County(ies) Surface Area1 (acres) Surface Area1 (sq. mi.) Nevada Area Number
Lake Tahoe Basin
[Incline Village, Glenbrook, Stateline]
Carson City, Douglas, Washoe 88,960 139 90
Truckee Canyon Segment
[Verdi]
Washoe 53,760 84 91
Washoe Valley
[Washoe City]
Washoe 52,480 82 89
Pleasant Valley
[Reno, Washoe City]
Washoe 24,960 39 88
Truckee Meadows
[Reno, Sparks]
Washoe 129,920 203 87
Sun Valley
[Sun Valley, Sparks]
Washoe 6,400 10 86
Spanish Springs Valley
[Sparks, Reno]
Washoe 48,640 76 85
Tracy Segment
[Sparks, Fernley]
Lyon, Storey, Washoe 182,400 285 83
Warm Springs Valley
[Sparks]
Washoe 158,080 247 84
Dodge Flat
[Wadsworth]
Washoe 58,880 92 82
Pyramid Lake Valley
[Nixon, Sutcliffe]
Washoe 430,080 672 81
Winnemucca Lake Valley
[Nixon, Gerlach]
Pershing, Washoe 237,440 371 80
Total Truckee River Basin   1,472,000 2,300  

1 Hydrographic areas and surface areas are for the Nevada portion of the Truckee River Basin only.

Source: Nevada Hydrographic Basin Statistical Summary, Office of the State Engineer, Nevada Division of Water Resources and Nevada Division of WaterPlanning, Department of Conservation and Natural Resources, Carson City, Nevada, 1988.

A Hydrologic Overview of the Lake Tahoe and Truckee River Basins

Major hydrologic features of the Truckee River Basin include Lake Tahoe and the Lake Tahoe Basin, the 105-mile long Truckee River, a number of lesser upstream storage lakes and reservoirs, various tributaries, and the Truckee River's terminus,(10) Pyramid Lake. The Truckee River system (omitting Lake Tahoe and its major tributary, the 15-mile long Upper Truckee River) may be thought of as consisting of five (5) major river reaches including: (1) the 15-mile reach between the Truckee River's origin beginning at the Lake Tahoe Dam at Tahoe City, California; (2) the 20-mile reach flowing through the upper Truckee River canyon between Truckee, California, and Verdi, Nevada, a reach which cuts through the Carson Range of the Sierra Nevada Mountains; (3) the 15-mile reach through the Truckee Meadows and the cities of Reno and Sparks, Nevada, to Vista; (4) the 30-mile reach from Vista to Wadsworth through the lower Truckee River canyon, and cutting through the Virginia Mountain Range; and (5) the 25-mile reach below Wadsworth, Nevada, traversing a broad alluvial valley to Pyramid Lake.

Lake Tahoe is an alpine lake located in the Sierra Nevada Mountains at an elevation of 6,223 feet (its natural rim) above mean sea level (MSL).(11) The lake is 22 miles long and between 8 and 13 miles wide, and has a shoreline of some 75 miles. In terms of ranking, Lake Tahoe is the third deepest lake in North America and the tenth deepest lake in the world. Lake Tahoe's surface water temperatures vary from a winter minimum of 40-45F to a summer maximum of 65-75F. At depths below 500 feet, the water remains a constant 39F.(12) The lake lies on the border between California and Nevada at 120 degrees west longitude. This north-south border runs through a line just to the east of the approximate centerline of Lake Tahoe, turning in a southeasterly direction at 39 degrees north latitude, thereby placing approximately two-thirds of Lake Tahoe within the State of California and one-third within the State of Nevada.(13)

Lake Tahoe's surface area covers 193 square miles (123,520 acres) and its depth has been recorded at 1,645 feet (based on its "normal" lake surface level of 6,228 feet MSL),(14) giving it a total estimated volume of approximately 122 million acre-feet, enough water to cover the entire surface area of the State of Nevada to a depth of approximately 1.72 feet.(15) Lake Tahoe has an average evaporation loss of some 350,000 acre-feet per year,(16) equivalent to about 34 inches of evaporation per year. The lake was formed along an ancient fault line which later filled with water during the Pleistocene, or glacial epoch some 2 million to 500,000 years ago. Scientific examination of the lake's bottom has found that lakebed sediments extend at least 2,600 feet below the lakebed.(17) The maximum prehistoric depth has been reported to have been up to 7,000 feet.(18)

Lake Tahoe is directly fed by 63 creeks and streams which drain the Lake Tahoe Basin. The principal tributaries of Lake Tahoe include the Upper Truckee River, which drains an area extending for 15 miles due south of Lake Tahoe, Trout and Taylor creeks, also located at the south end of Lake Tahoe, and Ward and Blackwood creeks. Together, these five streams carry more than one half (averaging 166,290 acre-feet per year) of Lake Tahoe's average surface water inflows of 310,000 acre-feet per year.(19) The Lake Tahoe Basin also includes a number of other lakes, including Fallen Leaf Lake (1,400 acres), Marlette Lake (381 acres), Upper and Lower Echo Lakes (330 acres), Cascade Lake (210 acres), and Spooner Lake (97 acres). Numerous other small lakes and ponds comprise an additional 600 acres of surface water within the basin.(20)

Table 2--Lake Tahoe's Principal Gaged Stream Inflowsa

Average Annual Runoff Volumes in Acre-Feet [Flow Rates in Cubic Feet per Second]b
By Gaging Station Location
(Listed by Gaging Station Number--See notes on respective average, low, and high water years)
Average Water Year (see notes) Low Water Year (see notes) High Water Year (see notes)
Upper Truckee River (South Lake Tahoe, CA)
(Gaging Station 10336610)1
71,311
[98.5 cfs]
21,140
[29.2 cfs]
146,970
[203 cfs]
Taylor Creek (near Baldwin Beach, CA)
(Gaging Station 10336626)2
30,910
[42.7 cfs]
6,940
[9.58 cfs]
64,000
[88.4 cfs]
General Creek (near Meeks Bay, CA)
(Gaging Station 10336645)3
11,800
[16.3 cfs]
3,590
[4.96 cfs]
25,120
[34.7 cfs]
Blackwood Creek (near Tahoe Pines, CA)
(Gaging Station 10336660)4
26,280
[36.3 cfs]
6,310
[8.71 cfs]
53,140
[73.4 cfs]
Ward Creek (near Sunnyside, CA)
(Gaging Station 10336676)5
18,390
[25.4 cfs]
3,830
[5.29 cfs]
42,710
[59.0 cfs]
Third Creek (at Incline Beach, NV)
(Gaging Station 10336698)6
5,630
[7.80 cfs]
2,110
[2.92 cfs]
10,210
[14.1 cfs]
Incline Creek (at Incline Beach, NV)
(Gaging Station 10336700)7
4,740
[6.55 cfs]
1,820
[2.51 cfs]
11,150
[15.4 cfs]
Marlette Creek (south of Sand Harbor, NV)
(Gaging Station 10336715)8
1,740
[2.40 cfs]
42
[0.058 cfs]
6,000
[8.29 cfs]
Glenbrook Creek (at Glenbrook, NV)
(Gaging Station 10336730)9
890
[1.23 cfs]
260
[0.36 cfs]
2,180
[3.01 cfs]
Logan House Creek (north of Cave Rock, NV)
(Gaging Station 10336740)10
300
[0.42 cfs]
37
[0.051 cfs]
870
[1.20 cfs]
Edgewood Creek (near Stateline, NV)
(Gaging Station 10336760)11
2,300
[3.18 cfs]
1,570
[2.17 cfs]
3,290
[4.54 cfs]
Trout Creek (South Lake Tahoe, CA)
(Gaging Station 10336780)12
25,770
[35.6 cfs]
7,380
[10.2 cfs]
61,750
[85.3 cfs]

a Streams have been listed sequentially by their U.S. Geological Survey gaging station numbers. Includes on gaged streams.

b Gaging station runoff volumes are based on average annual rates of flow in [bracketed] cubic feet per second (cfs). Bolded figures above these rates of flow measures show the average annual corresponding runoff volumes in acre-feet. One acre-foot equals 325,851 gallons. As a conversion measure between the rate of flow and the total runoff, a continuous rate of flow of one cubic foot per second is equivalent to a total runoff of approximately 723.97 acre-feet per year.

Gaging Station Notes:

1 For years of record 1972-1995; High water year: 1983; Low water year: 1988;

2 For years of record 1969-1992; High water year: 1982; Low water year: 1977;

3 For years of record 1980-1995; High water year: 1982; Low water year: 1988;

4 For years of record 1961-1995; High water year: 1982; Low water year: 1977;

5 For years of record 1973-1995; High water year: 1983; Low water year: 1977;

6 For years of record 1970-1995; High water year: 1983; Low water year: 1988;

7 For years of record 1970-1995; High water year: 1995; Low water year: 1992

8 For years of record 1974-1995; High water year: 1983; Low water year: 1977;

9 For years of record 1972-1995; High water year: 1995; Low water year: 1992;

10 For years of record 1984-1995; High water year: 1984; Low water year: 1992;

11 For years of record 1993-1995; High water year: 1995; Low water year: 1994;

12 For years of record 1961-1995; High water year: 1983; Low water year: 1977.

Source: Water Resources Data, Nevada, Water Year 1995, U.S. Geological Survey Water-Data Report NV-95-1, Nevada District Office, Water Resources Division, U.S. Geological Survey, U.S. Department of the Interior, Carson City, Nevada, 1995.

Lake Tahoe's Inflows and Outflows (Water Budget)

Table 2, Lake Tahoe's Principal Stream Inflows, shows the inflows of the major streams flowing into Lake Tahoe which are monitored by the U.S. Geological Survey. This table presents average annual flows or discharges in acre-feet per year (based on annualized rates of flow in cubic feet per second) for specific river flow conditions and specific gaging station locations. Discharges and flow rates are presented for an "Average Water Year," "Low Water Year," and "High Water Year." These twelve principal streams provide a combined inflow for Lake Tahoe of approximately 192,000 acre-feet per year (based on an "average" water year and disregarding varying periods of record). This surface water inflow constitutes approximately 62 percent of the total surface water inflow into Lake Tahoe. For the purpose of assessing these inflows and their relationship to the total quantity of water generated within this basin, it may prove instructive to assess the combined inflows and outflows for the Lake Tahoe Basin. Hydrologically, this is done by developing a water budget, or an accounting of flows for the Lake Tahoe Basin by relating the various annual inflows, outflows, and the resultant change in storage. Writing this relationship to reflect a hydrologic balance, we have from the presentation of F. Eugene Rush (USGS, 1973):(21)

Inflows = Outflows +/- Change in Storage

Modifying this general expression for the specific hydrologic characteristics of the Lake Tahoe Basin, yields:

ISW + IGW + P = OSW + E + D +/- [Change] S

where the elements of inflow are: ISW =surface water inflow; IGW = ground water inflow; and P = lake-surface precipitation. The elements of outflow are: OSW = surface water outflow into the Truckee River at Tahoe City; E = lake-surface evaporation; and D = diversions from the lake (and out of the basin). S represents the change in Lake Tahoe's storage associated with the water budget period. Disregarding ground water inflows and setting S = 0 and D = 0 yields:

ISW + P = OSW + E

Using figures from Rush (representing a period of record 1901-1971), ISW = 310,000 acre-feet per year; P = 220,000 acre-feet per year (21.26 inches per year); Truckee River outflows at Tahoe City, OSW = 180,000 acre-feet per year; and a lake evaporation rate of E = 350,000 acre-feet per year (33.83 inches per year),(22) yields a (balanced) water budget of:

310,000 + 220,000 = 180,000 + 350,000

Consequently, under this scenario of assumed no ground water inflows and a long-term general stability in storage (i.e., S = 0), we may estimate that based on the contributions of surface water inflows and lake surface precipitation, the Lake Tahoe Basin generates approximately 530,000 acre-feet of water per year, of which 350,000 acre-feet, or 66 percent, are lost to evaporation.

The Upper Truckee River Basin

The upper Truckee River Basin, while not formally defined, may be thought of as that portion of the basin above the Truckee Meadows, an area containing the metropolitan cities of Reno and Sparks, Nevada. This upper basin includes those drainage areas encompassing the Lake Tahoe Basin, the upper Truckee River between Lake Tahoe and the town of Truckee, California, the Donner Lake drainage area to the west of Truckee, the Martis Creek drainage to the south and east of Truckee, the Prosser Creek and Little Truckee River drainage areas to the north and east of Truckee, and the upper Truckee Canyon below Hirschdale, California, and above Verdi, Nevada. The upper Truckee River Basin includes portions of the California counties of Alpine, El Dorado, Placer, Nevada, and Sierra. The Nevada portion of the upper Truckee River Basin includes parts of Carson City, and the counties of Douglas and Washoe.

The uppermost headwaters of the Truckee River begin with the Upper Truckee River above Lake Tahoe, flowing into the lake from the south. From Table 2, Lake Tahoe's Principal Stream Inflows, it may be seen that this river constitutes the major tributary to Lake Tahoe. Also from Table 2, it may be noted that both the Upper Truckee River and Trout Creek, another principal stream inflow, enter the lake at virtually the same location (the Truckee Marsh at South Lake Tahoe, California). The Upper Truckee River flows a total distance of approximately 15 miles from its headwaters located only about one mile northwest of Red Lake Peak (10,061 feet) in Alpine County, California. It was from this vantage point that John C. Frémont, while crossing the Sierra Nevada Mountains on his way to Sutter's Fort in present-day Sacramento, California, was reported to have first viewed the waters of Lake Tahoe on February 14, 1844.

After flowing some four miles from its origin below Red Lake Peak, the Upper Truckee River first picks up the waters flowing out of Dardanelles Lake and then, several hundred feet further downstream, the waters from Round Lake. After another two miles, the Upper Truckee River merges with Grass Lake Creek, which flows from Grass Lake and drains the area below Luther Pass on U.S. Highway 89, an area which borders Hope Valley and the Carson River Basin to the south. Just over three miles downstream from the confluence with Grass Lake Creek, the Upper Truckee River crosses U.S. Highway 50 and enters Lake Valley. After another two miles, the Upper Truckee River merges with Angora Creek, and then flows another nearly five miles (excluding extensive meanders) until it reaches Lake Tahoe at South Lake Tahoe. In earlier times, before the construction of the Tahoe Keys housing area and marina, the Upper Truckee River flowed into an area called the Truckee Marsh, an extensive wetland area which effectively filtered this river's waters, as well as those of Trout Creek, before they entered the lake. Today, by contrast, the beneficial filtration and stabilization effects once provided by this marshland have been mitigated by extensive dredging, filling, and lakeshore development.

Lake Tahoe has a single outlet consisting of the Truckee River, which flows out of the lake at Tahoe City, located on the northwestern shore of the lake in Placer County, California. Within California, Lake Tahoe is bordered (from south to north) by the counties of El Dorado and Placer. Within Nevada, Lake Tahoe is bordered by the counties of Douglas, Carson City, and Washoe. From this outlet to Lake Tahoe, the Truckee River travels a total distance of approximately 50 air miles and 105 river miles to its terminus, Pyramid Lake, located in the Nevada desert.

Table 3--Selected Upper Truckee River Basin Truckee River Inflows

Average Annual Runoff Volumes in Acre-Feet [Flow Rates in Cubic Feet per Second]a
By Gaging Station Location
(See notes below on complete period of record for average, low, and high water years)
Average Water Year (see notes) Low Water Year (see notes) High Water Year (see notes)
Lake Tahoe Outlet (at Tahoe City)
(Gaging Station 10337500)1
161,450
[223 cfs]
110
[0.15 cfs]
832,570
[1,150 cfs]
Donner Creek (at U.S. Highway 89)
(Gaging Station 10338700)2
60,890
[84.1 cfs]
18,750
[25.9 cfs]
102,800
[142 cfs]
Martis Creek (below Martis Dam)
(Gaging Station 10339400)3
19,470
[26.9 cfs]
5,000
[6.90 cfs]
53,940
[74.5 cfs]
Prosser Creek (below Prosser Dam)
(Gaging Station 10340500)4
65,950
[91.1 cfs]
17,660
[24.4 cfs]
154,930
[214 cfs]
Little Truckee River (below Boca Dam)
(Gaging Station 10344500)5
123,800
[171 cfs]
40,250
[55.6 cfs]
340,270
[470 cfs]
Bronco Creek (at Floriston, California)
(Gaging Station 10345700)6
9,920
[13.7 cfs]
4,400
[6.06 cfs]
15,420
[21.3 cfs]
Dog Creekb (at Verdi, Nevada)
(Gaging Station 10347310)7
7,530
[10.4 cfs]
830
[1.14 cfs]
14,190
[19.6 cfs]
Hunter Creekb (above Reno, Nevada)
(Gaging Station 10347620)8
5,280
[7.30 cfs]
790
[1.09 cfs]
9,770
[13.5 cfs]
Steamboat Creekb (at Steamboat, Nevada)
(Gaging Station 10349300)9
12,960
[17.9 cfs]
1,400
[1.92 cfs]
83,260
[115 cfs]
Steamboat Creekb (below Reno, Nevada)
(Gaging Station 10349980)10
31,200
[43.1 cfs]
16,290
[22.5 cfs]
46,190
[63.8 cfs]

a Gaging station runoff volumes are based on average annual rates of flow in [bracketed] cubic feet per second (cfs). Bolded figures above these rates of flow measures show the average annual corresponding runoff volume in acre-feet. One acre-foot equals 325,851 gallons. As a conversion measure between the rate of flow and the total discharge, a continuous rate of flow of one cubic foot per second is equivalent to a total runoff of approximately 723.97 acre-feet per year.

b Dog, Hunter, and the two Steamboat Creek gaging stations, while presented here, are actually considered in the lower Truckee River Basin. Steamboat Creek's gage readings below Reno do not include the effluent discharges from the Truckee Meadows Water Reclamation Facility.

Gaging Station Notes:


1 For years of record 1909-1995; High water year: 1983; Low water year: 1994.

2 For years of record 1993-1995; High water year: 1995; Low water year: 1994.

3 For years of record 1972-1995; High water year: 1983; Low water year: 1977.

4 For years of record 1964-1995; High water year: 1983; Low water year: 1977.

5 For years of record 1970-1995; High water year: 1983; Low water year: 1992.

6 For years of record 1993-1995; High water year: 1995; Low water year: 1994.

7 For years of record 1992-1995; High water year: 1995; Low water year: 1994.

8 For years of record 1993-1995; High water year: 1995; Low water year: 1994.

9 For years of record 1962-1995; High water year: 1983; Low water year: 1992.

10 For years of record 1993-1995; High water year: 1995; Low water year: 1994.

Source: Water Resources Data, Nevada, Water Year 1995, U.S. Geological Survey Water-Data Report NV-95-1, Nevada District Office, Water Resources Division, U.S. Geological Survey, U.S. Department of the Interior, Carson City, Nevada, 1996.

Upon leaving Lake Tahoe, the Truckee River first heads southwest for one-half mile, then turns due west for another mile and a half. Two miles downstream from Lake Tahoe, the Truckee River eventually turns northwest and then north towards the town of Truckee, California, which is located nearly 15 miles downstream from the lake. Along this reach numerous small streams enter the Truckee River between Tahoe City and the town of Truckee, to include (those with names) Bear Creek (4.2 miles downstream), Squaw Creek (5.8 miles downstream), Deer Creek (6.6 miles downstream), Pole Creek (7.7 miles downstream), Silver Creek (8.8 miles downstream), Deep Creek (9.4 miles downstream), and Spring Cabin Creek (10.8 miles downstream).

Nearly one mile above Truckee and 13.6 miles downstream from Lake Tahoe, Donner Creek, which drains from Donner Lake (5,933 feet MSL), enters the Truckee River. One mile below the town of Truckee, the river passes the Tahoe-Truckee sewage disposal plant,(23) a technically-advanced tertiary treatment plant not only serving the town of Truckee, but also serving much of the California portion of Lake Tahoe, excluding South Lake Tahoe.(24) Treated effluent from this facility is not returned to the Truckee River, but infiltrated into the ground. Three miles below the Truckee sewage disposal plant, the waters of Martis Creek enter the Truckee River. Martis Creek drains an extensive area of some 40 square miles to the south of the Truckee River including Martis Creek, as well as West, Middle, and East Martis creeks. These combined waters feed into Martis Creek Reservoir, located just above Martis Creek's confluence with the Truckee River. This reservoir, with a storage capacity of just over 20,000 acre-feet, was constructed in 1971 by the U.S. Army Corps of Engineers (COE) for flood control purposes; however, due to a leaking dam, only temporary storage is allowed. Some 2.8 miles below the confluence of Martis Creek and the Truckee River, the waters of Prosser Creek enter the river. Just upstream on Prosser Creek is Prosser Creek Reservoir with a storage capacity of nearly 30,000 acre-feet, and some 11 miles above this reservoir is Warren Lake and the headwaters of Prosser Creek. Waters of Prosser Reservoir are decreed for use for several purposes to include COE flood control, maintenance of instream flows (the "Floriston rates"), and for spawning flows for Pyramid Lake's endangered cui-ui fish species and its threatened Lahontan cutthroat trout.

Another 2.2 miles below Prosser Creek, the Truckee River receives the waters of the Little Truckee River flowing out of Boca Reservoir, which is located less than one-half mile above the Truckee River. The Little Truckee River is the largest of the Truckee River's tributaries and drains an extensive area stretching from just below Sierraville, California, and the Sierra Valley area, both of which are located in the Feather River Basin (California). In fact, these upper basins' headwaters are so close that there exists a diversion (with a priority date of 1870) from the upper reaches of the Little Truckee River into Webber Creek for supplemental irrigation use in Sierra Valley. In addition to Boca Reservoir, the Little Truckee River sub-basin also contains Stampede Reservoir, with a storage capacity of 226,000 acre-feet, and further upstream on Independence Creek, Independence Lake (Reservoir), with a storage capacity of 17,500 acre-feet.

Just over two miles downstream from the Truckee River's confluence with the Little Truckee River, the river passes the community of Hirschdale, California. It was at this location that between 25 and 13 million years ago, in Neocene times (the late Tertiary Period encompassing both the Pliocene and Miocene Epochs), Lake Truckee was formed from a basalt lava flow which dammed the Truckee River at this point and created a lake with a surface area of approximately 73 square miles and a maximum depth of 465 feet.(25) Three miles below Hirschdale the waters of Gray Creek intermittently, and sometimes violently, enter the Truckee River. The importance of Gray Creek to the hydrology of the Truckee River is amplified far beyond its actual contribution to the river's flow due to its periodic tendency, during particularly severe thunderstorms, to disgorge considerable quantities of mud and debris into the river. These instances have been so severe, in fact, as to have destroyed a timer-crib dam used for ice making (1880), turned the Truckee River red with mud through Reno (1890), and washed out railroad tracks and bridges at Gray Creek's confluence with the Truckee River (1884). More recently, Gray Creek has forced the closure of Reno's water treatment plants on several occasions (i.e., 1965, 1992, 1995). The Gray Creek watershed is characterized by steep terrain, extensive areas of timber cutting, over-grazing by livestock, and unstable soil conditions.(26)

Just over two miles below Gray Creek, the Truckee River encounters a diversion dam located at the community of Floriston, California. Here waters are diverted into a flume to be used some 1.8 miles further downstream at the Farad powerhouse. Floriston has had an interesting relationship with the Truckee River. It was at this location that in 1899 the Floriston Pulp and Paper Company (FP&PC) was constructed and began the daily discharge of up to 150,000 gallons of highly acidic waste directly into the river.(27) Despite court-ordered injunctions and the threat of a Nevada suit filed with the U.S. Supreme Court, direct and indirect discharges would continue through 1930 when the plant was finally closed. Somewhat inexplicably, for over 30 years, this plant persisted as the most significant source of water pollution on the Truckee River and severely degraded the quality of drinking water downstream in the Truckee Meadows and jeopardized aquatic wildlife and habitat throughout the lower reaches of the Truckee River.(28)

Approximately 0.7 miles below the Farad powerhouse, a U.S. Geological Survey (USGS) gaging station is located. This gaging station, commonly referred to as the Farad gaging station, is the most important water flow measurement site along the entire Truckee River system as it is used to insure that the river system's "Floriston rates" are met. These required rates of flow for the Truckee River originated in 1908 when the Truckee River General Electric Company (predecessor of present-day Sierra Pacific Power Company of Reno, Nevada) formed an agreement with the Floriston Land and Power Company and the Floriston Pulp and Paper Company to insure a minimum flow in the Truckee River throughout the year. These rates were later incorporated into the Truckee River General Electric Decree in 1915, a decree which settled a long-standing controversy over who would control and operate the Lake Tahoe Dam at Tahoe City.

In this controversy, the Truckee River General Electric Company owned the dam, but the U.S. Reclamation Service (USRS, predecessor of the U.S. Bureau of Reclamation, USBR) wanted both control over the dam and ownership of the waters of Lake Tahoe for its Truckee-Carson Irrigation Project (later renamed the Newlands Project) to be located in Churchill County, Nevada, in the Carson River Basin. The federal government eventually gained control over the operation of the dam through this 1915 decree, but not without concessions. The principal concession included the enforcement of the Floriston rates, which granted the power company minimum instream flows in order to generate electrical power at its several powerhouses along the river's reach. These rates of Truckee River flow have since been incorporated into the Truckee River Agreement (1935), which was later incorporated into the Orr Ditch Decree (1944).

Approximately 2.6 miles downstream from the Farad gaging station, the Truckee River encounters another dam which diverts water to the Fleish power station. One mile beyond this diversion, the Truckee River leaves California and enters the State of Nevada, and a mile further along it receives the return waters from the Fleish power station. Less than one mile beyond this point, some of the Truckee River's waters are diverted again, this time into the Coldrone Ditch. Below this point the Truckee River reaches Verdi, Nevada, and after another several miles, the Truckee River enters the Truckee Meadows, containing the cities of Reno and Sparks.

The Lower Truckee River Basin

The lower Truckee River Basin, while not strictly defined, may be considered as encompassing that portion of the basin including and downstream from the Truckee Meadows. This would include the Truckee Meadows and the cities of Reno and Sparks, and Pleasant Valley and Washoe Valley to the south, the latter valley containing Washoe Lake and Little Washoe Lake. Both these valleys are drained by Steamboat Creek, which then runs along the eastern portion of the Truckee Meadows and empties into the Truckee River near Vista and the beginning of the lower Truckee River canyon. Along the way, Steamboat Creek picks up the return flows of numerous irrigation ditches to the south of the Truckee River, the most important being Steamboat Ditch, Last Chance Ditch, and Lake Ditch, as well as the Boynton Slough (which picks up the waters of Cochran Ditch). The Boynton Slough is the recipient of some of these other ditches' return-flow waters as well. Also included in this lower Truckee River Basin is the lower Truckee River canyon running through the Virginia Range and extending between Vista (Sparks) and Wadsworth. The final segment of the lower Truckee River Basin lies below Wadsworth and includes a 25-mile long broad, alluvial valley stretching to Pyramid Lake. This portion of the basin also includes the Pyramid Lake Basin, and to the east over the Lake Range, the Winnemucca (dry) Lake Basin.(29)

The Truckee Meadows is a bowl-shaped valley, approximately 10 miles wide and 16 miles long, containing the cities of Reno and Sparks with a combined population of approximately 215,000 persons.(30) Several tributaries enter the Truckee River along this reach, the most important being Steamboat Creek, which also contains the treated effluent from the Truckee Meadows Water Reclamation Facility (formerly the Reno-Sparks joint sewage treatment plant). The Truckee Meadows constitutes the most important municipal and industrial use of the Truckee River's water in the basin, as well as the most important agricultural use of the Truckee River's waters within the basin. While municipal and industrial water use (withdrawals) in the Truckee Meadows total approximately 65,000 acre-feet per year, nearly three times this amount (172,383 acre-feet per year, 1973-1994) is diverted out of the lower Truckee River Basin at Derby Dam and into the Truckee Canal for agricultural use in the Newlands Project in the lower Carson River Basin. [See Table 5 for Truckee Canal flows.]

On the east side of the Truckee Meadows at Vista, the Truckee River enters the lower Truckee River canyon, which cuts through the Virginia Range. Nearly 2.5 miles after leaving the Truckee Meadows, the Truckee River comes abreast of Lockwood. It was at this point where Ice Age Lake Lahontan attained its maximum reach up the Truckee River during its peak highstand of some 4,380 feet MSL approximately 65,000 years ago. In fact, over the period of 65,000-12,500 years ago, referred to as the Wisconsin, or glacial age, Lake Lahontan experienced several highstands which brought it very near to this location.(31) Some 11.4 miles beyond this point the Truckee River passes Sierra Pacific Power Company's Tracy-Clark power station cooling ponds and 3.6 miles beyond this the river reaches Derby Dam, the most significant diversion to be encountered along the entire Truckee River. From this diversion dam the Truckee Canal takes off, first paralleling the river towards the east, then turning southward along the west side of the Lahontan Valley and crossing into the Carson River Basin, heading towards the lower Carson River where it empties into Lahontan Reservoir. Each year, on the average (1967-1994), just over 183,000 acre-feet (173,380 acre-feet per year since 1973) of Truckee River water have been diverted at this point for agricultural use on Newlands Project farmlands within the Truckee Division near Fernley, Nevada, and within the Carson Division around Fallon, Nevada.

Some 9.2 miles below Derby Dam the Truckee River enters the Pyramid Lake Paiute Indian Reservation. The reservation occupies almost 477,000 acres (745 square miles) with its dominant feature being the 108,000-acre (169 square-mile) Pyramid Lake. Reservation lands were initially withdrawn in 1859, a date which determined the priority date under the "reservation doctrine" for the Tribe's use (appropriation) of Truckee River waters for the irrigation of tribal lands. However, the Pyramid Lake Indian Tribe's history has been inextricably linked to the bounty of Pyramid Lake and the lower Truckee River fisheries. The concept of the federal reservation doctrine, under which these water rights were guaranteed and eventually adjudicated in the 1944 Orr Ditch Decree, is to reserve a sufficient supply of water to meet the intended purpose of the reservation.(32) Despite the historical importance of the Pyramid Lake fishery to the Paiute Indians and the clearly defined intent of the reservation doctrine, no water has ever been allocated to the restoration of Pyramid Lake or to the preservation of the lake's and river's fisheries.(33)

Some 1.8 miles after entering the Pyramid Lake Indian Reservation, the Truckee River passes Wadsworth. In the latter part of the 1800's, Wadsworth was an important rail center, particularly for the shipment of Pyramid Lake cutthroat trout to San Francisco markets and, beginning in 1869 with the completion of the transcontinental rail line, to points east as well. In 1888 alone, it was reported that approximately 250,000 pounds (125 tons) of Pyramid Lake cutthroat trout were shipped from Wadsworth. Further, it was also estimated that this represented only about one-half of the total catch of trout along the entire river system.(34) Eventually, over-fishing, pollution, and the blockage of upstream access for spawning spelled the doom of this sub-species of Lahontan cutthroat trout, a species which grew up to four feet in length and weighed between 40-60 pounds. After surviving for thousands of years in the waters of Lake Lahontan, Pyramid Lake, Lake Tahoe, and the Truckee River system, less than 100 years after the arrival of the first white man in 1844, this magnificent species of fish became extinct by the early 1940's.(35)

Near Wadsworth, the Truckee River turns from its eastward flow and heads northward, flowing through a broad alluvial valley that is bounded by Quaternary-age (Pleistocene) lacustrine deposits of ancient Lake Lahontan and Tertiary-age volcanic rocks. Approximately 14.5 miles below Wadsworth, measured along the course of the Truckee River, is the Numana Dam, which is the diversion dam for irrigation on the reservation. Approximately 3.5 miles below this is Nixon, and just over four miles below Nixon is the Marble Bluff Dam, which, along with the Pyramid Lake Fishway, was built 1975 in an effort to reduce further erosion in the lower Truckee River and to promote the spawning runs of the Pyramid Lake cui-ui endangered fish species.(36) Nearly four miles below Marble Bluff Dam, the Truckee River enters its terminus location, Pyramid Lake.

Pyramid Lake, as well as being the low point of the Truckee River Basin, was also the low point of the ancient Ice Age Lake Lahontan,(37) which covered some 8,655 square miles of northwestern Nevada as recently as 12,500 years ago and, at its peak surface elevation of 4,380 feet MSL (which occurred approximately 65,000 years ago), extended up the Truckee River to Lagomarsino Canyon near the present-day community of Lockwood.(38) Pyramid Lake, which is wholly contained within the Pyramid Lake Paiute Indian Reservation, is 30 miles long and ranges from 4 to 11 miles wide and covers approximately 169 square miles (108,000 acres) at a surface elevation of 3,800 feet MSL.(39) At this lake-surface elevation, Pyramid Lake has a maximum depth of 335 feet and contains approximately 21 million acre-feet of water.(40)

In a 1970 study of Pyramid Lake's water budget (inflows, outflows, and changes to lake storage), it was estimated that the lake's surface evaporation totaled some 440,000 acre-feet per year, equivalent to approximately 4.2 feet per year. Based on this rate of evaporation, which was recorded over a 40-year period from 1929-1969, combined with average annual lake inflows of 250,000 acre-feet and precipitation of 55,000 acre-feet onto the lake's surface, it was found that Pyramid Lake had suffered an average water deficit of about 135,000 acre-feet per year over this period of time.(41) This condition resulted in a dramatic decline in its water level since the early 1900's from about 3,870 feet MSL in July 1910 to 3,783.9 feet MSL on February 6, 1967 (42) and a resultant increase in the lake's salinity to nearly 5,100 parts per million of total dissolved solids.(43) Based upon an estimated average annual discharge of 519,270 acre-feet (1929-1969) at the Farad gaging station over this same period of record, less than half (48.1 percent) of the Truckee River's waters entering Nevada have actually made it to Pyramid Lake during this period.

More recent gaging records (1958-1994) show that an average of nearly 357,000 acre-feet have entered Pyramid Lake each year (Nixon gaging station), which, when combined with estimated lake surface evaporation and precipitation amounts above, still results in a net deficit of some 28,000 acre-feet per year. Using this annual "average" lake water budget deficit of 28,000 acre-feet, and Pyramid Lake's most recent highstand of nearly 3,798.94 feet MSL (April 30, 1996), along with its corresponding estimated volume of 21,605,000 acre-feet, we may estimate that for a normal series of years, the lake will decline by one foot of surface elevation every four years.(44)

Pyramid Lake is the home of the endangered cui-ui fish species (Chasmistes cujus), a bottom sucker found only in this lake, and the threatened Lahontan cutthroat trout (Oncorhynchus clarki henshawi). The Lahontan cutthroat trout species was introduced into Pyramid Lake in the 1950's after the native sub-species, the Pyramid Lake cutthroat trout became extinct in the early 1940's. The survival of these two fish species has become a crucial issue with respect to upstream storage (Stampede and Prosser reservoirs), maintaining river flows sufficient for spawning runs, and the rights to unallocated flood waters in the Truckee River.

Immediately to the east of Pyramid Lake and over the Lake Range lies the dry lake bed of Winnemucca Lake, which, when it contained water, was nearly as long as Pyramid Lake, but not nearly as wide. Throughout recent history, and even before extensive Truckee River diversions began at Derby Dam in the early 1900's, this lake's status varied from a shallow lake to a mud flat and marsh. Finally, in 1938 the lake dried up completely, never to be filled again. Even so, when high water years in these earlier times permitted, Truckee River inflows into this area created an important wetland and feeding and nesting area to numerous waterfowl visiting this area along the Pacific Flyway. During particularly wet years, an extensive pool of relatively shallow water forms at the northern end of this expanse, fed by local surface and ground water inflows.

Table 4--Selected Truckee River Runoff and Rates of Flow

Average Annual Runoff Volumes in Acre-Feet [Flow Rates in Cubic Feet per Second]a
By Gaging Station Location
(See notes below on complete period of record for average, low, and high water years)
Average Water Year (see notes) Low Water Year (see notes) High Water Year (see notes)
Truckee River at Tahoe City
(Gaging Station 10337500)1
161,450
[223 cfs]
110
[0.15 cfs]
832,570
[1,150 cfs]
Truckee River up from Donner Creek
(Gaging Station 10338000)2
220,810
[305 cfs]
23,460
[32.4 cfs]
594,380
[821 cfs]
California-Nevada Border (Farad Gage)
(Gaging Station 10346000)3
542,980
[750 cfs]
133,210
[184 cfs]
1,768,680
[2,443 cfs]
Truckee River at Reno (below Kietzke Bridge)
(Gaging Station 10348000)4
487,960
[674 cfs]
76,740
[106 cfs]
1,701,330
[2,350 cfs]
Truckee River below Reno (McCarran Bridge)
(Gaging Station 10348200)5
479,270
[662 cfs]
64,220
[88.7 cfs]
1,717,980
[2,373 cfs]
Truckee River at Vista (below Steamboat Creek)
(Gaging Station 10350000)6
579,180
[800 cfs]
114,390
[158 cfs]
2,016,980
[2,786 cfs]
Truckee River below Tracy
(Gaging Station 10350400)7
565,420
[781 cfs]
111,490
[154 cfs]
1,977,180
[2,731 cfs]
Truckee River below Derby Dam (1,500 feet)
(Gaging Station 10351600)8
269,320
[372 cfs]
4,460
[6.16 cfs]
1,759,270
[2,430 cfs]
Truckee River above Pyramid Lake (Nixon)
(Gaging Station 10351700)9
362,710
[501 cfs]
17,450
[24.1 cfs]
1,888,860
[2,609 cfs]

a Gaging station runoff volumes are based on average annual rates of flow in [bracketed] cubic feet per second (cfs). Bolded figures above these rates of flow measures show the average annual corresponding flow or discharge in acre-feet. One acre-foot equals 325,851 gallons. As a conversion measure between the rate of flow and the total runoff, a continuous rate of flow of one cubic foot per second is equivalent to a total discharge of approximately 723.97 acre-feet per year.

Gaging Station Notes:

1 For years of record 1909-1995; High water year: 1983; Low water year: 1994

2 For years of record 1945-1995; High water year: 1952; Low water year: 1994

3 For years of record 1909-1995; High water year: 1983; Low water year: 1931

4 For years of record 1907-1995; High water year: 1983; Low water year: 1931

5 For years of record 1977-1995; High water year: 1983; Low water year: 1992

6 For years of record 1900-1995; High water year: 1983; Low water year: 1992

7 For years of record 1972-1995; High water year: 1983; Low water year: 1992

8 For years of record 1918-1995; High water year: 1983; Low water year: 1931

9 For years of record 1958-1995; High water year: 1983; Low water year: 1992

Source: Water Resources Data, Nevada, Water Year 1995, USGS Water-Data Report NV-95-1, Nevada District Office, Water Resources Division, U.S. Geological Survey, U.S. Department of the Interior, Carson City, Nevada, 1996.

Truckee River Flows (Runoff) and Rates of Flow

Table 4, Selected Truckee River Flows, presents average annual flows or discharges in acre-feet per year (based on annualized rates of flow in cubic feet per second) for specific river flow conditions and specific gaging station locations. Of note is that the differences between the gaging station below Tracy and the one below Derby Dam reflect primarily the diversions into the Truckee Canal. Also, the difference between the discharge recorded below Derby Dam and the gage at Nixon represents, in large part, the return flows from the Truckee Canal (Gilpin Spill and Pyramid Spill). Of particular importance are the high variability in the Truckee River's flows, not only from extreme lows to highs, but also from "average" flows to lows and highs. These variations, which realistically tend to be more "average", i.e., typical, than flows during "average" years, have tended to exacerbate Truckee River issues with respect to agricultural water needs, spawning flow requirements, municipal and industrial needs, and water quality.

Truckee River Water-Related Issues

Currently, the most significant water-related issues within the Truckee River Basin are concerned with: (1) diversions out of the basin at Derby Dam for use on Newlands Project farmlands in the Carson River Basin; (2) highly erratic periods of precipitation and river flows combined with limited upstream storage to accommodate extreme periods of drought (e.g., 1987-1994); (3) obtaining significant flows for the restoration and preservation of the Pyramid Lake fishery; (4) increasing water needs for the Reno-Sparks metropolitan area; (5) water quality problems in the lower Truckee River below the Truckee Meadows Water Reclamation Facility; and (6) the allocation of unused (unappropriated) Truckee River flood waters between the demands of the Truckee-Carson Irrigation District (TCID), operating on behalf of the Newlands Project farmers, and the demand for these waters by the Pyramid Lake Indian Tribe to restore the Pyramid Lake and lower Truckee River fisheries.

Over the years, these complex and inter-related Truckee River issues have manifested themselves in numerous lawsuits and continuing litigation involving a number of principal interest groups, including: (1) the U.S. Department of the Interior, representing varied interests (i.e., U.S. Bureau of Reclamation, Bureau of Indian Affairs, and the U.S. Fish and Wildlife Service); (2) TCID as operator of the Newlands Irrigation Project; (3) the City of Fallon and Churchill County representing domestic water needs in the Lahontan Valley; (4) the Pyramid Lake Paiute Indian Tribe; (5) water purveyors in the Truckee Meadows (i.e., Sierra Pacific Power Company and Washoe County); (6) the cities of Reno and Sparks and the effects of their treated effluent on downstream water quality; (7) the U.S. Environmental Protection Agency representing both the interests of endangered and threatened fish species in Pyramid Lake and Truckee River water quality issues; and (8) the states of Nevada and California, to name the more prominent.

Table 5, Selected Truckee River and Truckee Canal Flows, presents flows and differences in flows of the lower Truckee River waters above and below Derby Dam and above and below the Newlands Project's Truckee Division along the Truckee Canal. While these differences may provide a general indication of the actual level of these respective diversions, further explanation should be made with respect to this presentation. First, "average" annual flows and corresponding rates of flow for these gaging stations have been calculated over a consistent period of the water years (October 1st through September 30th) 1973 through 1994. Second, due to the river distances involved, differences above and below Derby Dam on the Truckee River, as well as above and below the Truckee Division on the Truckee Canal, reflect not only the water diversions at these points, but also river and canal losses due to evaporation, seepage, and phreatophyte(45) usage between the specific gaging station locations.(46)

Table 5--Selected Truckee River and Truckee Canal Flows

Average Flow Volumes Calculated for the Water Years 1973-1995


Average Annual Runoff Volumes in Acre-Feet [Rates of Flow in Cubic Feet per Second]a
By Gaging Station Location
(See notes below on respective periods for average, low, and high water years)
Average of 1973-1994 Water Years Low Water Year High Water Year
Truckee River at Farad (State Line)
(Gaging Station 10346000)1
551,110
[761 cfs]
133,210
[184 cfs]
1,768,660
[2,443 cfs]
Truckee River below Tracy, Nevada and above Derby Dam
(Gaging Station 10350400)2
565,690
[781 cfs]
111,490
[154 cfs]
1,977,160
[2,731 cfs]
Truckee River Immediately below Derby Dam (1,500 feet)
(Gaging Station 10351600)3
362,420
[501 cfs]
4,460
[6.16 cfs]
1,759,250
[2,430 cfs]
Difference--Above/Below Derby Damb 203,270 --* 217,910
Truckee Canal near Wadsworth above the Truckee Division and 22.94 miles above Lahontan Reservoir
(Gaging Station 10351300)4
170,890
[236 cfs]
83,980
[116 cfs]
287,420
[397 cfs]
Truckee Canal near Hazen below Truckee Division and 3.35 miles above Lahontan Reservoir
(Gaging Station 10351400)5
127,220
[176 cfs]
29,970
[41.4 cfs]
238,910
[330 cfs]
Difference--Above/Below Truckee Divisionb 43,670 54,010 48,510

a Gaging station flows or discharges are based on average annual rates of flow in [bracketed] cubic feet per second (cfs). Bolded figures above these rates of flow measures show the average annual corresponding flow or discharge in acre-feet. One acre-foot equals 325,851 gallons. As a conversion measure between the rate of flow and the total discharge, a continuous rate of flow of one cubic foot per second is equivalent to a total discharge of approximately 723.97 acre-feet per year.

b Flows, rates of flow, and differences for the average of the 1973-1995 water years are based on a consistent period of record. diversions associated with these points, but also stream and canal operational losses due to evaporation, seepage, and phreatophytes between the specific gaging station locations.

* Not relevant; difference represents different periods of record (1992 compared to 1931).

Gaging Station Notes:

1 For complete years of record 1909-1995 average equals 542,980 acre-feet; High water year: 1983; Low water year: 1931.

2 For complete years of record 1973-1995 average equals 565,420 acre-feet; High water year: 1983; Low water year: 1992.

3 For complete years of record 1918-1995 average equals 269,320 acre-feet; High water year: 1983; Low water year: 1931.

4 For complete years of record 1967-1995 average equals 181,720 acre-feet; High water year: 1978; Low water year: 1983.

5 For complete years of record 1967-1995 average equals 135,380 acre-feet; High water year: 1978; Low water year: 1983.

Source: Water Resources Data, Nevada, various issues, Water Resources Division, USGS, Carson City, Nevada.

It should also be noted that in comparing the figures of Table 5 and Table 4, the average annual flow ("average year") measured at the gaging station located approximately 1,500 feet below Derby Dam on the Truckee River (Table 5) of 354,660 acre-feet per year (period of record 1973-1994) is virtually the same as the average annual flow of 356,920 acre-feet per year (period of record 1958-1994) recorded even further downstream at Nixon (Table 4). Logically, one would expect that given the considerable distance between these gaging stations (i.e., approximately 35 miles), the effects of evaporation, seepage, agricultural diversions, and phreatophyte use would greatly reduce flows lower down in the river. This apparent anomaly is due, in part to the different periods of record, but more importantly, it is due to return flows from the Truckee Canal via the Gilpin Spill and the Pyramid Spill, which dump waters diverted at Derby Dam back into the Truckee River between the gaging station located just below Derby Dam and Wadsworth. These waters are returned to the Truckee River before the first gaging station on the Truckee Canal and are therefore not counted as Truckee Canal diversions.

Recordings taken at the Truckee River Farad gaging station, located just upstream from the California-Nevada border, are used to measure the Truckee River's waters actually entering the State of Nevada. Based on the figures presented in Table 5, it may be seen that during the water years of 1973-1994, approximately 65 percent of the average annual of Truckee River waters entering the State of Nevada and recorded at the USGS Farad gaging station (548,200 acre-feet) near the California-Nevada state line during this 1973-1994 period of record were available in the river below Derby Dam (354,660 acre-feet). Not shown in this table, over this same period of time, the Nixon gaging station above Pyramid Lake recorded average annual inflows of 388,880 acre-feet, indicating that of the average Truckee River flows entering Nevada, nearly 71 percent actually made it to Pyramid Lake. Also, of the total average annual volume of Truckee River water entering the state, 31.4 percent was diverted into the Truckee Canal (an average of 172,380 acre-feet per year) during this 1973-1994 period of record.(47)

The effects of this interbasin transfer on the Truckee River's terminus, Pyramid Lake, have been profound. For example, the maximum surface elevation for Pyramid Lake was recorded in September 1891 at 3,878.2 feet MSL, while the minimum elevation was recorded during February and March of 1967 at 3,783.9 feet MSL, representing a maximum decline in Pyramid Lake's surface elevation in recent times of 94.3 feet.(48) Along with this decline in Pyramid Lake's surface elevation has come an even more significant decline in the lake's total volume, resulting in increased total dissolved solids (i.e., TDS, or salinity) concentrations, which now stand at approximately 5,100 milligrams per liter (mg/l).(49) This degradation of the water quality of Pyramid Lake, along with warmer water temperatures in the lower Truckee River due to both reduced river flows below Derby Dam and discharges from the Truckee Meadows Water Reclamation Facility, have combined to degrade the water quality in the lower basin and jeopardize the lake's continued existence as a viable fishery. The restricted Truckee River flows into Pyramid Lake since diversions for the Newlands Project began in 1905 have been a contributing factor in the extinction of the Pyramid Lake cutthroat trout in the early 1940's.

When John C. Frémont first visited Pyramid Lake and the lower reaches of the Truckee River in January 1844, the Pyramid Lake cutthroat trout, a sub-species of the Lahontan cutthroat trout, was reported as being abundant in these waters, growing to a length of up to four feet and weighing some 40-60 pounds. In his diary of his travels, Frémont commented that &quotTheir [Pyramid Lake cutthroat trout's] flavor was excellent--superior, in fact, to that of any fish I have ever known. They were of extraordinary size--about as large as the Columbia River salmon--generally from two to four feet in length.&quot(50)

These magnificent fish relied on the Truckee River for their spawning runs in late winter and early spring, traveling up the river's entire length as far as Donner Lake and Lake Tahoe. Here they used the cool, pristine waters of these upper basin lakes, and their clean gravel beds, to lay their eggs. Within 100 years of Frémont's arrival, however, due to a combination of over-fishing, river impediments to upstream spawning in the form of dams for irrigation, logging, and hydroelectric power generation, logging debris and sawdust choking the gravel beds, reduced inflows into Pyramid Lake due to diversions at Derby Dam, and extensive pollution from discharges from lumber and paper mills, and ore processing operations, this once-abundant fish species would become extinct by the early 1940's.

While some factors contributing to the extinction of the Pyramid Lake cutthroat trout have been greatly mitigated, e.g., pollution, over-fishing, and some of the river impediments, the lake itself continues to suffer from restricted Truckee River inflows due to water diversions at Derby Dam as well as other upstream water uses. Continued water diversions at Derby Dam at historical levels, as well as increasing upstream municipal and industrial consumptive uses, may well result in a persistent water deficit for Pyramid Lake.(51) Continued restricted inflows will adversely affect the endangered cui-ui fish species and the threatened Lahontan cutthroat trout, a trout form which was introduced into Pyramid Lake in the 1950's to replace the extinct Pyramid Lake sub-species. Even today, there is still no natural reproduction of Lahontan cutthroat trout in Pyramid Lake or the lower Truckee River; it continues to be artificially maintained entirely by hatchery stock.(52)

The Truckee River and the Newlands Irrigation Project

Arguably the single greatest controversy within the Truckee River Basin centers on the interbasin transfer of water from this basin into the Carson River Basin and the effects that these diversions have had on Pyramid Lake. Truckee River diversions have taken place since 1905 at Derby Dam, which is located on the lower Truckee River 11 river miles upstream from Wadsworth. The dam has been operated by the Truckee-Carson Irrigation District (TCID) since 1926 and diverts Truckee River waters into the 32.5-mile Truckee Canal for conveyance to the Carson River Basin. Derby Dam, originally constructed in 1905 by the U.S. Reclamation Service, is one of a number of impoundment, diversion, conveyance, and distribution facilities which comprise the Newlands Irrigation Project. Major components of this reclamation project include stored waters in Lake Tahoe, Donner Lake, Prosser Creek Reservoir, and Boca Reservoir, the Lake Tahoe Dam, Derby Dam, the Truckee Canal, the Truckee Division of the Newlands Project (consisting of approximately 5,300 water-righted acres), Lahontan Dam and Reservoir on the lower Carson River, the Carson Diversion Dam located approximately six miles below Lahontan Dam, the principal &quotT&quot (T-Line) and &quotV&quot (V-Line) canals below the Carson Diversion Dam, and an extensive labyrinth of lesser canals, laterals, and ditches for distribution of project waters to the Carson Division of the Newlands Project in Lahontan Valley (consisting of approximately 60,000 water-righted acres).

Under the 1944 Orr Ditch Decree, TCID was granted the right, with a 1902 priority date (Claim 3), to divert up to 1,500 cubic feet per second (cfs) at Derby Dam, although physical canal constraints limit diversions to a nominal capacity of approximately 900 cfs. According to diversion records, from 1910 through 1966, Truckee River diversions at Derby Dam averaged approximately 240,000 acre-feet per year.(53) In 1967, the USBR eliminated the diversion of Truckee River waters solely for power generation (i.e., Lahontan Dam and a generating station on the &quotV&quot canal).(54) This action dramatically reduced Truckee River diversions at Derby Dam. As a result, over the 1967-1994 period of record, an average of 183,160 acre-feet per year of Truckee River water have been sent down the Truckee Canal towards Lahontan Reservoir in the Carson River Basin. Of this total, an average of 136,830 acre-feet per year actually reach Lahontan Reservoir each year; the remaining 46,330 acre-feet per year are either diverted to the Newlands Project's Truckee Division near Fernley, or are lost to evaporation, seepage, or phreatophytes along the canal's course.(55) These diversions, which have taken place since 1905, flow into Lahontan Reservoir to be used on Newlands Project farmlands located in the Carson Division of that reclamation project around the City of Fallon in Churchill County, Nevada.(56)

Like the Lake Tahoe Dam at the Truckee River headwaters at Tahoe City, Derby Dam is operated by the TCID under agreement with the USBR and in accordance with the Orr Ditch Decree (and incorporated Truckee River Agreement) and Newlands Project Operating Criteria and Procedures (OCAP). These operating criteria allow diversions up to 1,500 cfs from:

  1. the remainder of Floriston rates and return flows from upstream diversions;
  2. the right to Truckee River tributary water;
  3. and (3) any water bypassed or released to obtain space to store flood waters in reservoirs if the water right holder did not identify a use for the release.(57)

Under Newlands Project OCAP, the quantity of water which may be diverted from the Truckee River at Derby Dam varies with the determination of the irrigation entitlement each year and the predicted runoff from the Carson River and water in storage in Lahontan Reservoir.(58) Project OCAPs, based on the 1973 Gesell Opinion (U.S. District Court, Washington, D.C.), attempt to minimize the use of Truckee River waters as much as possible. The current OCAP (beginning in 1988) bases project water entitlements on actual water-righted acreage intended to be irrigated and the appropriate water duty assigned to project bottom lands (3.5 acre-feet per acre per year) and project bench lands (4.5 acre-feet per acre per year), in accordance with the 1980 Alpine Decree.(59)

Principal Storage Facilities of the Truckee River Basin

Major storage facilities of the Truckee River Basin (excluding the basin's terminus, Pyramid Lake), along with their characteristics, capacities, and operating requirements, are detailed below. River flows and water releases from these lakes and reservoirs are controlled by the Federal Watermaster in Reno, Nevada, in accordance with specific operating criteria, specifically, the 1944 Orr Ditch Decree and its incorporated 1935 Truckee River Agreement and the Floriston rates.(60)

  1. Lake Tahoe--The first dam at Lake Tahoe's exit into the Truckee River was constructed in the early 1870's, while the existing Lake Tahoe Dam, located at Tahoe City in Placer County, California, was constructed in 1913. The Lake Tahoe drainage area covers approximately 506 square miles. Water is stored only in the top 6.1 feet of Lake Tahoe, from a surface elevation of 6,223.0 feet above mean sea level (MSL), assumed to be the lake's natural rim, to an elevation of 6,229.1 feet MSL. Total storage capacity within this upper 6.1 feet equals approximately 744,600 acre-feet and is used to supplement Floriston rates in conjunction with natural runoff of other tributaries and Boca Dam releases. The Lake Tahoe Dam is owned by the USBR and operated under agreement by the TCID for the Newlands Project in Churchill County, Nevada. Lake Tahoe's storage capacity is not considered part of the U.S. Army Corps of Engineers (COE) flood control system. Lake Tahoe waters may be exchanged for water from Prosser Creek Reservoir (the Tahoe-Prosser Exchange Agreement)(61) in order to maintain a live stream below the Lake Tahoe Dam without adversely affecting Nevada water users' storage. Whenever possible, Lake Tahoe releases must be sufficient to maintain a minimum instream flow of 50-70 cfs downstream from the dam (varies with season).

  2. Donner Lake--The first dam on Donner Lake was built in 1877, while the current dam was constructed in the 1930's. Donner Lake drains an area of only approximately 14 square miles. Water in Donner Lake is privately owned by Sierra Pacific Power Company (SPPCo) of Reno, Nevada, and TCID, and is not required to be used to meet Floriston rates. The dam is jointly owned and operated by SPPCo and TCID. Lake storage levels range from between 5,924.0 feet MSL and 5,935.8 feet MSL, and provides for 9,500 acre-feet of storage capacity. The SPPCo portion of the stored water is used to supplement Reno-Sparks municipal and industrial water use in the Truckee Meadows; the TCID portion is used to supplement Newlands Project irrigation water requirements. After Donner Lake fills, lake inflows are passed through to supplement Floriston rates. Lake storage is not part of COE flood control system. The State of California requires a minimum flow of 2-3 cfs downstream from the dam for maintaining fish habitat.
  3. Martis Creek Reservoir--The Martis Creek Dam was constructed by the COE in 1971 and was intended to store waters from a 40 square mile drainage area to include not only Martis Creek, but the East, West, and Central Martis Creeks as well. In accordance with COE requirements, this reservoir, with a total storage capacity of 20,400 acre-feet, serves only flood control purposes. While legislation allows for other uses, only temporary storage is currently permitted due to an unsafe, leaking dam. Except during flood storage, reservoir outflows are set to equal inflows.
  4. Prosser Creek Reservoir--The Prosser Creek Reservoir was constructed by the USBR in 1962 to store waters from a 50 square mile drainage area beginning 11 miles to the west at Warren Lake. The reservoir, with a total capacity of 29,800 acre-feet, is owned and operated by the USBR for three purposes: (a) as part of the COE Truckee River flood control program; (b) the storage of water under the terms of the Tahoe-Prosser Exchange Agreement (which provides that a portion of this water, when available, may be used to meet Floriston rates in lieu of making such releases from Lake Tahoe); and (c) to meet the spawning flow needs of Pyramid Lake's endangered cui-ui fish species and its threatened Lahontan cutthroat trout, or for other federal purposes. The State of California generally requires a minimum of natural flow or 5 cfs, whichever is less, downstream from the dam for maintaining fish habitat.
  5. Independence Lake--The original Independence Lake Dam was constructed in 1879 and created a storage capacity of 3,000 acre-feet. After SPPCo acquired ownership of the lake and dam in 1937, the dam was enlarged in 1939 to its present size with a total storage capacity of 17,500 acre-feet. Independence Lake drains an area of only eight square miles. Like Donner Lake water, the waters of Independence Lake are privately owned and are not required to be used to meet Floriston rates; the stored waters are owned by SPPCo and supplement the SPPCo water supply for the Reno-Sparks municipal and industrial water use during droughts. The lake's first storage priority is for 3,000 acre-feet of (original) storage; an additional 14,500 acre-feet of storage is permitted after Boca Reservoir is full and the Floriston rates and Truckee River diversion rights (Orr Ditch Decree rights) are satisfied. The State of California requires a minimum flow of 2 cfs downstream from the dam for maintaining fish habitat.
  6. Stampede Reservoir--Stampede Dam and Reservoir, constructed by the USBR in 1970, drains an area of some 136 square miles and has a total capacity of 226,000 acre-feet. Water must be used primarily for spawning flows for the endangered cui-ui fish species and the threatened Lahontan cutthroat trout of Pyramid Lake. Storage space is also part of COE flood control plan. Water may be stored in Stampede Reservoir only after: (1) Floriston rates and Truckee River diversion rights have been satisfied; (2) Boca Reservoir (below Stampede Reservoir) is full; and (3) Independence Lake (above Stampede Reservoir) is full. Due to its relatively junior water rights, this reservoir seldom fills and has been targeted as a prime storage location for Reno-Sparks municipal water as part of the Negotiated Settlement (Public Law 101-618) and the implementation of a new Truckee River Operating Agreement (TROA). The State of California requires a minimum flow of 30 cfs downstream from the dam for maintaining fish habitat (although this agreement has expired, the rates of flow have been maintained).
  7. Boca Reservoir--The original Boca dam was built around 1868 for ice harvesting. The present, much larger dam, was constructed just upstream in 1937 and created a reservoir with a total capacity of 40,800 acre-feet and a drainage area, including the entire Little Truckee River Basin (including both Independence Lake and Stampede Reservoir) of some 172 square miles. Title to stored water is held by the USBR and the dam is operated by the Washoe County Water Conservation District (WCWCD). The reservoir's water is used in conjunction with Lake Tahoe water to maintain Floriston rates and to provide part of the required COE flood control capacity. Up to 25,000 acre-feet of water may be stored in Boca Reservoir only after Floriston rates are satisfied and Independence Lake's first storage priority of 3,000 acre-feet has been satisfied. The balance may not be filled unless the Newlands Project diversion right at Derby Dam (on the lower Truckee River) has been satisfied. SPPCo stores a small portion (800 acre-feet) of its privately owned stored water (POSW) rights here. There are no minimum downstream flow requirement associated with Boca Reservoir.
  8. Derby Dam/Truckee Canal/Lahontan Reservoir--Although Lahontan Reservoir is not a storage facility of the Truckee River Basin, it does store Truckee River waters diverted at Derby Dam on the lower Truckee River. Derby Dam, which is located approximately 11 miles upstream from Wadsworth, Nevada, is the regulating device by which Truckee River waters are diverted into the Truckee Canal for use within the Truckee Division of the Newlands Project and for storage in Lahontan Reservoir in the Carson River Basin for use within the Carson Division of the Newlands Project. The dam, originally named the Truckee River Diversion Dam, was completed by the USRS in June 1905, whereas the Truckee Canal was not completed through to the Carson River until August 1906. Lahontan Reservoir was not completed until 1915, at which time the Truckee Canal's outlet was re-routed slightly upstream so as to enter Lahontan Reservoir instead of flowing directly into the Carson River. Diversions and releases are conducted in accordance with the Truckee River Agreement, the Orr Ditch Decree, and Newlands Project Operating Criteria and Procedures (OCAP), which allow for a maximum diversion of up to 1,500 cfs (Orr Ditch Decree right, although current canal nominal capacity is only 900 cfs) from: (a) remainder of Floriston rates and return flows from upstream diversions; (b) right to Truckee River tributary water; and (c) any water bypassed or released to obtain space to store flood waters in reservoirs if water right holder did not identify a use for the release. Under the more recent project OCAP determination method begun in 1988, the quantity of water which may be diverted from the Truckee River at Derby Dam varies with the irrigation entitlement each year (water-righted acreage actually to be irrigated and the appropriate water duty for bench and bottom lands) and the predicted runoff from the Carson River and water in storage in Lahontan Reservoir.

Current Diversions from the Truckee River and Lake Tahoe Basins

There currently exist seven (7) recognized water diversions from the Truckee River Basin and/or the Lake Tahoe Basin (as part of the Truckee River Basin) as listed below:

  1. Lake Tahoe Basin--The are a number of diversions of Lake Tahoe's waters out of the Lake Tahoe Basin for domestic uses; however, only three result in waters actually leaving the Truckee River Basin entirely. First, Harvey Place Reservoir, located in Alpine County, California, in the Carson River Basin, receives advanced secondary treated effluent from the South Tahoe Public Utility District (STPUD) in the Lake Tahoe Basin (Truckee River Basin).(62) Effluent exports, amounting to approximately 5,000 acre-feet per year (4.5 million gallons per day),(63) are routed from the southern end of Lake Tahoe through a pipeline over Luther Pass from El Dorado County, California, into Alpine County, California, and the Carson River Basin. These effluent exports began in 1968 when Indian Creek Reservoir was constructed by the South Tahoe Public Utility District. Beginning in 1989, exports were re-routed to Harvey Place Reservoir and Indian Creek Reservoir was turned into a freshwater recreational area managed by the Bureau of Land Management (BLM). Second, Carson Valley, located in the Carson River Basin in Douglas County, Nevada, receives the treated effluent from the Incline Village (Nevada) General Improvement District (IVGID) and the Douglas County Sewer Improvement District (DCSID). Together these utilities cover the wastewater treatment of the Nevada portion of the Lake Tahoe Basin (Truckee River Basin), located in Washoe County, Carson City, and Douglas County. The IVGID pumps approximately 1,700 acre-feet per year (1.5 million gallons per day) of treated waste water from its Incline Village treatment plant, along the east side of the lake to Spooner Summit, then down Clear Creek Valley to wetlands located in the northeastern portion of the Carson Valley. The DCSID handles sewage collection and treatment on the Nevada side of Lake Tahoe from Glenbrook to the Nevada-California state line at South Lake Tahoe. It pumps approximately 2,600 acre-feet per year (2.3 million gallons per day) of treated effluent over the Kingsbury Grade (Haines Canyon) and then to a storage reservoir on the east side of the Carson Valley in the Pine Nut Range, where it receives winter storage. During the irrigation season, these stored waters are then pumped back across the Carson Valley and used for supplemental irrigation purposes. According to the California-Nevada Interstate Compact, Nevada's gross diversions of the waters of Lake Tahoe are set at a maximum of 11,000 acre-feet per year, while California's diversions of Lake Tahoe's waters cannot exceed 23,000 acre-feet per year.
  2. Echo Lake--Pacific Gas and Electric Company (PG&E) diverts waters from the Lake Tahoe Basin at Echo Lake to the upper South Fork of the American River. This diversion out of the Lake Tahoe Basin totals approximately 1,500 acre-feet per year and is used for hydroelectric power generation at their El Dorado Power Plant.
  3. Third Creek--Water diversions from Third Creek constitute an intrabasin diversion from a tributary of Lake Tahoe into Washoe Valley of 5.5 cubic feet per second. The Third Creek diversion actually takes water from the Lake Tahoe Basin only, as the water remains within the Truckee River Basin. Third Creek is located on the west (Lake Tahoe) side of the Mount Rose highway summit. A portion of its waters are diverted down the east side of the Carson Range by means of Ophir Creek and then into Washoe Lake, then to Steamboat Creek and eventually to the Truckee River below Reno near the Reno-Sparks sewage treatment plant.
  4. Marlette Lake--Water in this lake, which is owned by the State of Nevada, is diverted from the Lake Tahoe Basin, pumped over the Carson Range to Hobart Creek Reservoir, enters Franktown Creek below the reservoir, and is sometimes sold for delivery to the Hobart Storage System for use by Virginia City (after being piped across Washoe Valley to Five-Mile Reservoir) and Carson City, both of which lie within the Carson River Basin. These water users have generally replaced such demands from other sources within the Carson River Basin. Diversions total approximately 3,000 acre-feet per year.
  5. Franktown Creek/Hobart Creek Reservoir--A tributary of Washoe Lake, which eventually flows into the Truckee River through Steamboat Creek, Franktown Creek is the outlet stream for Hobart Creek Reservoir which is fed from Hobart Creek. [Hobart Creek Reservoir waters are also supplemented by Marlette Lake water. See Marlette Lake diversions, above.] Waters from Franktown Creek are piped into the Hobart Storage System for use by Virginia City (Five-Mile Reservoir) and Carson City, both of which are in the Carson River Basin.
  6. Sierra Valley--Water is diverted by canal from the Little Truckee River, a primary tributary of the Truckee River, into Webber Creek for the Sierra Valley Water Company for supplemental irrigation use in the Sierra Valley. These waters eventually flow into the Feather River Basin in California. The maximum diversion rate is 60 cubic feet per second during the growing season (March 15th through September 30th) with a priority date of 1870. As a supplemental supply of irrigation water, these interbasin water diversions vary from 1,500 acre-feet per year to 10,000 acre-feet per year and have typically averaged approximately 5,700 acre-feet per year.
  7. Lower Truckee River Diversion (Derby Dam)--Waters are taken out of the lower Truckee River at Derby Dam and transported to Lahontan Reservoir in the Carson River Basin via the Truckee Canal. TCID, representing the Newlands Project farmers, originally contracted with the USBR in 1926 for a firm supply, when available, of 406,000 acre-feet per year to be delivered to the Lahontan Reservoir outlet works and to canal headings using waters from both the Carson and Truckee rivers. More recent Operating Criteria and Procedures call for the maximum use of Carson River waters whenever possible. Diversions at Derby Dam on the lower Truckee River have averaged approximately 183,160 acre-feet per year over the 1967-1994 period of record and 172,380 acre-feet per year over the more recent 1973-1994 period of record.(64) Diversion records show that over the period of 1910-1966, when Truckee River waters were also used for power generation at Lahontan Dam and on the "V" canal below the Carson Diversion Dam, these diversions averaged a considerably greater 240,000 acre-feet per year.(65)

Based on these individual diversion amounts, the maximum total water diversion out of the Truckee River Basin in any one year could total approximately 192,000 acre-feet, of which nearly 90 percent of the total diversions out of the Lake Tahoe and Truckee River basins would constitute diversions at Derby Dam alone. The total of these diversions also represent nearly 32 percent of the average annual flow of 548,200 acre-feet (1973-1994 period of record) of Truckee River water crossing the California-Nevada border and recorded at the Farad gaging station.

Derby Dam, the Truckee Canal, and Lahontan Reservoir

Derby Dam, located on the lower Truckee River approximately 11 miles upstream from Wadsworth, is the regulating structure by which Truckee River waters are diverted into the 32.5 mile long Truckee Canal. These waters are used for irrigation within the Truckee Division of the Newlands Project, as well as for storage in Lahontan Reservoir in the lower Carson River Basin. The dam, originally named the Truckee River Diversion Dam, was completed by the USRS (renamed the USBR in 1923) in June 1905. The Truckee Canal was completed through to the lower Carson River in following year. Without upstream storage on the Carson River; however, the project's agricultural season was subject to the vagaries of the highly seasonal and largely unregulated flows of both these river systems. As a result, in dry years the growing season was frequently truncated, production levels diminished, and multiple cropping not always possible. These problems were significantly mitigated in 1915 with the completion of Lahontan Dam and Reservoir, which provided the project with 294,000 acre-feet of storage capacity (approximately 317,000 acre-feet with flash boards installed) on the lower Carson River just upstream from the project's farms.

Lahontan Dam and other project structures, stretching as far upstream on the Truckee River as the outlet dam at Lake Tahoe, are currently operated by TCID under a temporary contract with the USBR. The project's water rights, water diversions, and water duties are specified in various decrees and agreements, including the 1935 Truckee River Agreement, the 1944 Orr Ditch Decree, the 1980 Alpine Decree, and the current Newlands Project OCAP. The terms of these stipulations allow for the diversion of up to 1,500 cfs (Claim 3 of the Orr Ditch Decree with a 1902 priority date, although the canal's nominal capacity is only 900 cfs)(66) from the Truckee River at Derby Dam and water duties(67) of 3.5 acre-feet per acre per year (bottom lands) and 4.5 acre-feet per acre per year (bench lands) for project irrigated acreage, currently totaling approximately 64,000 water-righted acres and 58,000 acres actually being irrigated.

In 1968 the Pyramid Lake Paiute Indian Tribe filed a lawsuit against the Secretary of the Interior claiming that the 1967 OCAP, the first set of operating criteria to be established by the Secretary for this project, was allowing water to be wasted within the Newlands Irrigation Project. The suit was primarily intended to improve project efficiencies and thereby reduce Truckee River diversions at Derby Dam. In February 1973, the Gesell Opinion (U.S. District Court in Washington, D.C.) was issued which called for a new OCAP and an immediate reduction in Newlands Project diversions from the 1926 contract delivery quantity of 406,000 acre-feet per year (using both Carson and Truckee River waters) to 350,000 acre-feet per year, with step-wise reductions thereafter to an ultimate level of 288,129 acre-feet per year.(68) A lawsuit was subsequently filed in 1974 by the City of Fallon against the imposition of this new OCAP. The appeals process on this suit continued through 1988, at which time a new, final OCAP, and new water allocation method, were instituted.

Under the present project OCAP, the quantity of water which may be diverted from the Truckee River at Derby Dam varies with the determination of the irrigation entitlement each year and the predicted runoff from the Carson River and water in storage in Lahontan Reservoir.(69) These more recent project OCAPs, as originally derived from the 1973 Gesell Opinion, have attempted to minimize the use of Truckee River waters as much as possible. Controversy continues to surround these diversions, however, which have been deemed excessive by the Pyramid Lake Indian Tribe.

On behalf of the Pyramid Lake Indian Tribe, the USDI now claims that between 1973 and 1987 (15 years) TCID over-diverted approximately 1,057,000 acre-feet of Truckee River water and is calling for this recoupment to be repaid to Pyramid Lake.(70) Churchill County, the City of Fallon, and TCID officials, as well as Newlands Project farmers, have claimed that because the City of Fallon filed a 1974 lawsuit against the implementation of the new OCAP, in part calling for a complete Environmental Impact Statement (EIS) under the National Environmental Protection Act (NEPA), the 1973 OCAP should not have been implemented. TCID has further claimed that, as the appeals process for these suits against the implementation of the new OCAP were not fully resolved until 1988, the claim for recoupment of excessive diversions before that date is unreasonable.(71) The recoupment of Truckee River waters remains a major issue in the eventual resolution of the Negotiated Settlement Act (Public Law 101-618) which, when passed by Congress in November 1990, was intended to settle the myriad of claims and outstanding lawsuits associated with these issues.

Of particular concern to the Lahontan Valley farmers with respect to this 1990 Truckee- Carson-Pyramid Lake Water Rights Settlement Act is Section 209(h)(1), which specifies that, among other things, outstanding debts owed by TCID to the federal government relating to the project costs will not be canceled unless and until an agreement has been reached concerning claims for recoupment of water diverted in excess to the amounts permitted by applicable OCAP. More recent actions (December 1995) by the City of Fallon and Churchill County involved filing an injunctive suit to prevent the implementation of the Negotiated Settlement and halt the continued purchase of water rights in the project for transfer to the Lahontan Valley wetlands until a new Environmental Impact Statement has been completed.(72)

One week after that action was taken by Churchill County officials, the U.S. Justice Department filed a lawsuit against TCID to recoup, with "interest," excess waters diverted by TCID over the 15-year period from 1973 through 1987.(73) This controversy over Truckee River diversions may have become further exacerbated when Churchill County officials filed a request with the USBR for supplemental Truckee River water rights under the Orr Ditch Decree (Claim No. 3),(74) and the recent (May 1994) resurrection of TCID's original September 1930 request for 100,000 acre-feet of unappropriated (flood) flows of the Truckee River.(75)

At issue in TCID's 1930 filing are the Truckee River's excess (unallocated, i.e., flood) flows, waters which the Pyramid Lake Paiute Indian Tribe would prefer to see flow into Pyramid Lake. Hearings before the Nevada State Engineer on this request were not held until May 1994, at which time the USDI categorically stated their objection to TCID's request and their refusal to permit any federal facilities to be used for diversion, conveyance, storage, or distribution of additional waters from the Truckee River, even if a state water permit was issued. Based on this "threshold issue" alone, on May 31, 1994, the State Engineer denied TCID's application without ruling on whether there exists unappropriated water, whether this application would interfere with existing rights, or whether the application would threaten to prove detrimental to the public interest.(76) Subsequently, on June 30, 1994, TCID filed an appeal in the Third Judicial Court of the State of Nevada, in and for the County of Churchill, to the State Engineer's ruling. The court remanded the case back to the State Engineer for a re-hearing so additional evidence and testimony could be presented. These hearings were held in early 1996 and the State Engineer has yet to issue a ruling on the matter.

The Churchill County request is particularly singular as it represents the first such interbasin demand for Truckee River waters for a use other than for agriculture in the Lahontan Valley. Of importance in this respect is that many individual water users in this area rely on shallow alluvial aquifers, portions of which are recharged by Newlands Project water. This has heightened local concerns that water rights purchases on lands irrigated by the project could dramatically affect the reliability of future water supplies.(77) The Negotiated Settlement specifies that the Secretary of the Interior is authorized to "...operate and maintain the [Newlands] project for the purpose of...municipal and industrial water supply in Lyon and Churchill counties, Nevada."(78)

Truckee River Operating Requirements and Procedures

Truckee River flows are regulated by a number of agreements, decrees, and river operating requirements extending as far back as the turn of the century. These are monitored and enforced by a Federal Watermaster in Reno, Nevada. The four most critical to present-day river operations include: (1) the 1908 Floriston rates; (2) the 1915 Truckee River General Electric Decree; (3) the 1935 Truckee River Agreement; and (4) the 1944 Orr Ditch Decree. Over time, each subsequent agreement or operating criteria has incorporated those established river operating requirements in effect before it. Specifically, the Floriston rates were incorporated into the Truckee River General Electric Decree, which was subsequently incorporated into the Truckee River Agreement which, in turn, became the river operating component of the Orr Ditch Decree. Details of these rate agreements, decrees, and operating criteria are presented below:

Floriston Rates--Currently represents the primary operational criteria of the Truckee River between its source (Lake Tahoe) and its terminus (Pyramid Lake). These river flow rates date back to a 1908 agreement among the Truckee River General Electric Company (predecessor to the present-day Sierra Pacific Power Company--SPPCo), the Floriston Land and Power Company, and the Floriston Pulp and Paper Company. This agreement required that "...there shall be maintained a flow of water in the said Truckee River at Floriston [California] of not less than 500 cubic feet per second from the First day of March to the 30th day of September inclusive, in each year, and of not less than 400 cubic feet per second from the 1st day of October to the last day of February, inclusive, in each year." The Floriston rates were subsequently incorporated into the 1915 Truckee River General Electric Decree, by which the U.S. Reclamation Service (predecessor to the USBR) gained an easement to operate the Lake Tahoe outlet dam in return for guaranteeing these year-round flow rates for run-of-the-river users--hydropower and a pulp and paper mill.

Truckee River General Electric Decree--Represented the resolution, through a 1915 federal court consent decree, of a lengthy series of conflicts, litigation, and negotiations between the U.S. Reclamation Service (USRS) and the Truckee River General Electric Company. In 1902, the Truckee River General Electric Company, through a complicated series of real estate transactions, had obtained title to the Lake Tahoe Dam, surrounding lands, and the hydropower plants on the Truckee River. The USRS was in desperate need of Lake Tahoe water for its Truckee-Carson (Newlands) Irrigation Project, then nearing completion near Fallon in Churchill County, Nevada. This decree granted the USRS an easement, for a purchase price of $139,500, to the Lake Tahoe Dam and surrounding property owned by the power company. On its part, the USRS was required to provide certain year-round flow rates (the 1908 Floriston rates), measured at a stream gage near the state line, to support hydropower generation. While the Truckee River General Electric Decree dictated how the Lake Tahoe Dam would be operated, it did little to solve the concerns of residents of the lake and lessen California's concerns over the apportionment of Lake Tahoe's waters.(79)

Truckee River Agreement--The Truckee River Agreement, finalized in 1935, represents the current basis for the operation of the Truckee River, including its tributaries and diversions, between its source (Lake Tahoe) and its terminus (Pyramid Lake). Parties to this agreement included TCID, serving the irrigation rights of agricultural water users of the Newlands Project in Churchill County, Nevada, Sierra Pacific Power Company, serving primarily the municipal and industrial water needs of the cities of Reno and Sparks, Nevada, and the Washoe County Water Conservation District, serving the agricultural water users in the Truckee Meadows. Operation of upstream reservoirs is under the supervision of a Federal Watermaster in Reno, Nevada, who administers court-imposed requirements under the (1944) Orr Ditch Decree to supply water to achieve Floriston rates (mandated river flow rates) at the California-Nevada border (currently measured at the Farad gaging station). The Truckee River Agreement provides for the operation of storage facilities, especially Lake Tahoe, to satisfy these rights and required the building of Boca Dam and Reservoir. The Floriston rates essentially constitute a minimum instream flow in the river, as long as water is physically available in Lake Tahoe and Boca Reservoir to support the rates. Water may only be stored in Lake Tahoe and Boca Reservoir when rates are being met. The precise definition for the Floriston rates contained in the Truckee River Agreement is as follows:

  1. Floriston Rates means the rate of flow in the Truckee River at the head of the diversion penstock at Floriston, California, measured at the Iceland gage [currently the Farad gage] consisting of an average flow of 500 cubic feet of water per second each day during the period commencing March 1 and ending September 30 of any year, and an average flow of 400 cubic feet per second each day during the period commencing October 1 and ending the last day of the next following February of any year.
  2. Reduced Floriston Rates means rates of flow in the Truckee River, measured at the Iceland gage [currently the Farad gage], effective and in force during the period commencing November 1 and ending the next following March 31 of each year, determined as follows:
    1. 350 cubic feet per second whenever the elevation of the water surface of Lake Tahoe is below 6,226.0 feet above sea level and not below 6,225.25 feet above sea level;(80) and
    2. 300 cubic feet per second whenever the water surface elevation of Lake Tahoe is below 6,225.25 feet above sea level.(81)

In addition to crucial operating criteria for Truckee River operations, the 1935 Truckee River Agreement further contained language intended to settle the long-standing disputes over pumping Lake Tahoe when if fell below its natural rim of 6,223.0 feet MSL by:

  1. Establishing the natural conditions in the bed and banks of Lake Tahoe and of the Truckee River near Tahoe City, Placer County, California, and prohibiting any alteration of such natural conditions without the approval of the Attorney General of the State of California, and, in fact, allowing parties to the agreement the right to restore these areas to their natural condition, as necessary;
  2. Prohibiting the creation of any other outlet of Lake Tahoe in addition to the present and natural outlet at the head of the Truckee River;
  3. Prohibiting the removal of water from Lake Tahoe for irrigation or power uses by any means other than gravity except upon the declaration of the U.S. Secretary of the Interior; and
  4. Prohibiting the removal of water from Lake Tahoe for sanitary or domestic uses by any means other than gravity, except upon the condition that the Departments of Health of the States of Nevada and California, or other officers exercising similar authority, shall first have made and filed with the Attorney General of the State of Nevada and the Attorney General of the State of California certificates showing that a necessity for such pumping of Lake Tahoe exists.(82)

Orr Ditch Decree--The 1944 Orr Ditch Decree, which incorporates the Truckee River Agreement, affirmed numerous individual water rights (both municipal and industrial and agricultural), including Truckee River diversion rights earlier than 1939. This decree represented a tabulation or adjudication of water rights for the Truckee River within Nevada and its tributaries regulated through a series of reservoirs and irrigation canals, administered by the U.S. District Court Federal Watermaster in Reno, Nevada. The Orr Ditch Decree represented the culmination of a "friendly suit" (U.S. v. Orr Ditch Water Company, et al.) filed in 1913 by the USRS to quantify water rights on the Truckee River in Nevada in order to secure Truckee River water rights for its Truckee-Carson (Newlands) Irrigation Project. In combination with the Truckee River Agreement and the Floriston rates, the Orr Ditch Decree currently represents the basis for operation of the Truckee River between its source (Lake Tahoe) and its terminus (Pyramid Lake). The Orr Ditch Decree incorporates the provisions of the Truckee River Agreement, which provides for operation of storage facilities, especially Lake Tahoe, to satisfy Truckee River water rights. The Floriston rates constitute the chief operational objective on the Truckee River today and originated as a turn-of-the-century flow requirement for original run-of-the-river users--hydropower and a pulp and paper mill. While the Orr Ditch Decree establishes water rights for entities within Nevada using the Truckee River's waters, the Truckee River Agreement, as part of that Decree, determines the operational mechanisms to satisfy those rights.(83)

Changes to Pyramid Lake Over the 1987-1994 Drought Period

Table 6, Pyramid Lake Changes Over the 1987-1994 Drought Period, shows the annual and cumulative changes in Pyramid Lake's surface elevation and its total volume over the 1987-1994 drought period. In total, the Pyramid Lake declined by 21.5 feet from a maximum lake depth of 356.6 feet in 1986 to a maximum lake depth 335.1 feet in 1994,(84) and also declined by 2,430,000 acre-feet in total volume from a lake volume of 23,500,000 acre-feet in 1986.

Table 6--Pyramid Lake Changes Over the 1987-1994 Drought Period

Changes in Lake Surface Elevation and Lake Volume From 1986--Annual and Cumulative

Water Year1 Elevation (feet-MSL)2 Change* (feet) Cumulative (feet) Volume (acre-feet) Change* (acre-feet) Cumulative (acre-feet)
1986 3,815.6 +5.0 -- 23,500,000 +580,000 --
1987 3,813.8 -1.8 -1.8 23,290,000 -210,000 -210,000
1988 3,810.4 -3.4 -5.2 22,890,000 -400,000 -610,000
1989 3,807.4 -3.0 -8.2 22,550,000 -340,000 -950,000
1990 3,804.0 -3.4 -11.6 22,170,000 -380,000 -1,330,000
1991 3,801.2 -2.8 -14.4 21,850,000 -320,000 -1,650,000
1992 3,797.9 -3.3 -17.7 21,490,000 -360,000 -2,010,000
1993 3,796.3 -1.6 -19.3 21,310,000 -180,000 -2,190,000
1994 3,794.1 -2.2 -21.5 21,070,000 -240,000 -2,430,000

1 Elevations and volume recorded as of September 30th of each year; water years run from October 1st through September 30th.
2 Feet above mean sea level (MSL).
* Lake elevation and volume changes measured from prior year.

Source Data: Water Resources Data, Nevada, Water Year [various years], U.S. Geological Survey Water-Data Report, Water Resources Division, U.S. Geological Survey, U.S. Department of the Interior, Carson City, Nevada.

Effects of the 1995 Water Year

A near-record year of precipitation in 1995--168 percent of normal snow water content in the Lake Tahoe Basin as of April 1, 1995, and 184 percent of normal snow water content in the Truckee River Basin (excluding the Lake Tahoe Basin)--did much to recharge the groundwater and fill lakes and reservoirs in the Truckee River Basin after eight years of drought conditions (1987-1994). Table 7, 1995 Water Year Impacts on Truckee and Carson River Storage, highlights the effects of this single very wet year on the principal upstream water storage locations in the Truckee River Basin, as well as the storage change to Lahontan Reservoir in the Carson River Basin. Many of these Truckee River Basin storage reservoirs are of special importance to the Carson River Basin, and particularly the Newlands Irrigation Project, due to Derby Dam diversion rights from upstream storage--i.e., Lake Tahoe, Donner Lake, Prosser Creek Reservoir, and Boca Reservoir. Pyramid Lake's increased volume of some 410,000 acre-feet represented a recovery in only one year of nearly 17 percent of the volume lost (2,430,000 acre-feet) over the previous eight years (1987-1994) [see Table 6, above].

Table 7--1995 Water Year1 Impacts on Truckee River Basin Storage

Surface Water Elevations Measured in Feet; Volumes in Acre-Feet (AF)
Lake/Reservoir
[Maximum Elevation--feet]
[Storage Capacity--acre-feet]
Minimum Volume (AF) [Date] Maximum Volume (AF) [Date] Estimated Volume Change (AF)
Lake Tahoe
Elevation--MSL2 (feet)
[6,229.1 feet]
[744,600 acre-feet]3
-240,8104 6,221.01 feet [October 31, 1994] 485,600 6,226.99 feet [July 29, 1995] 726,410 5.98 feet
Donner Lake
[9,500 acre-feet]5
2,800 [November 4, 1994] 9,620 [June 26, 1995] 6,820
Prosser Reservoir
[29,840 acre-feet]
9,461 [March 23, 1995] 31,430 [July 11, 1995] 21,969
Independence Reservoir
[17,500 acre-feet]
10,300 [January 1-4, 1995] 17,700 [August 4, 1995] 7,400
Stampede Reservoir
[226,500 acre-feet]
66,843 [November 4, 1994] 236,199 [July 19, 1995] 169,356
Boca Reservoir
[40,870 acre-feet]
5,775 [October 1, 1994] 39,176 [July 10-11, 1995] 33,401
Pyramid Lake
Elevation--MSL2 (feet)
20,970,000 3,793.17 feet [January 3, 1995] 21,380,000 3,796.94 feet [July 31, 1995] 410,000 3.77 feet
Total Change in Storage for Above Lakes/Reservoirs (AF) 1,375,356
Lahontan Reservoir6
[294,000 acre-feet]7
5,530 [October 3, 1994] 316,300 [July 25, 1995] 310,770

Table Notes:
1 The 1995 (hydrologic) water year encompassed the period from October 1, 1994 through September 30, 1995. Figures are provisional USGS data and are subject to revision.
2 MSL--surface elevation above mean sea level.
3 Measures only usable storage capacity above Lake Tahoe's natural rim of 6,223.0 feet above mean sea level (MSL) and its maximum allowable elevation of 6,229.1 feet MSL; equivalent to approximately 10,172 acre-feet per inch of surface elevation change above 6,223.0 feet MSL.
4 Represents additional storage required (deficit) to bring Lake Tahoe's surface elevation up to its natural rim of 6,223.0 feet MSL.
5 Measures only usable storage in top 11.8 feet from 5,924.0 feet MSL to 5,935.8 feet MSL.
6 Lahontan Reservoir is listed due to its importance in terms of the use of Truckee River waters. Carson River flows at the Fort Churchill Gage approximate flows into Lahontan Reservoir which, in combination with Lahontan Reservoir's storage level, will affect the quantity of Truckee River diversions at Derby Dam.
7 Lahontan Reservoir storage capacity estimated at nearly 317,000 acre-feet with flashboards installed on the dam's spillway crest.

Source Data: U.S. Geological Survey, Water Resources Division, U.S. Department of the Interior, Carson City, Nevada. Data are provisional and subject to revision.

Water Basin Snowpack Water Content Trends

Table 8, Northern Nevada Water Basin Snow Water Content, presents an historical perspective of precipitation levels in Northern Nevada's major water basins over the years 1980 through 1996 based on the percentage of average snow water content as of April 1st of each year (average year = 100 percent). This period is of special significance to the hydrology of this area as it included the wettest year on record for the Sierra Nevada Mountain water basins (1983) and the Humboldt River Basin (1984), as well as the most severe drought period on record (1987-1994) for these water basins. These figures emphasize the extreme variations in snowpack water content from year to year. This presentation also shows how these Northern Nevada watersheds are generally affected by the same winter storm systems, resulting in typically similar patterns of precipitation and snow water content measures. These year-to-year variabilities add support to concerns over using the concept of an "Average Water Year" for watershed forecasting and planning purposes, as there are so few such years in reality. The graphs present the snow water content trends for the Lake Tahoe Basin and the Truckee River Basin, specifically.

Table 8--Northern Nevada Water Basin Snow Water Content

Snowpack Water Equivalent as a Percent of Average for This Time of Year
As of April 1--Percent of Water Basin Average (Average = 100%)
Water Year Lake
Tahoe
Basin
Truckee
River
Basin1
Carson
River
Basin
Walker
River
Basin
Upper
Humboldt
Basin
Lower
Humboldt
Basin
1980 134% 134% 153% 170% 121% 131%
1981 62% 58% 70% 73% 55% 30%
1982 141% 149% 147% 156% 178% 173%
1983 202% 205% 206% 227% 157% 272%
1984 103% 100% 95% 106% 227% 296%
1985 90% 90% 85% 85% 115% 145%
1986 142% 134% 158% 170% 115% 115%
1987 56% 56% 48% 46% 75% 92%
1988 29% 32% 36% 40% 52% 44%
1989 93% 100% 87% 70% 103% 141%
1990 41% 50% 47% 47% 63% 45%
1991 64% 60% 63% 69% 72% 74%
1992 46% 45% 37% 54% 39% 33%
1993 149% 158% 123% 144% 95% 98%
1994 44% 50% 43% 46% 47% 36%
1995 168% 184% 157% 185% 73% 95%
1996 116% 121% 106% 113% 110% 107%
Period Percent of Water Basin Average (Average = 100%)
Wet Years (1982--1986); Drought Years (1987--1994):
82-86 136% 136% 138% 149% 158% 200%
87-94 65% 69% 61% 65% 68% 70%

1 Snow water content figures for the Truckee River Basin exclude the Lake Tahoe Basin.

Source: Natural Resources Conservation Service (NRCS), U.S. Department of Agriculture, Reno, Nevada, May 1996.

With respect to the figures in Table 8, despite the seemingly wide variability in the snowpack water content for the Lake Tahoe and Truckee River basins, the average for the entire period for these basins was very close to the entire period of record average of 100 percent. Specifically, for the Lake Tahoe Basin, the average for this 1980-1996 period was 99 percent, while the average for the Truckee River Basin (excluding the Lake Tahoe Basin) was 102 percent,(85) thereby indicating that while the values seem highly volatile, the pattern was, on the whole, "average."

A Water Budget for Pyramid Lake

Similar to the development of a water budget for Lake Tahoe, a water budget for Pyramid Lake may prove useful in assessing the hydrologic changes and conditions in this body of water which represents the terminus of the Truckee River Basin. For the purpose of assessing Pyramid Lake's inflows and outflows, we can develop an accounting of related flows by assessing the various annual inflows, outflows, and the resultant change in storage, i.e., change in lake volume. Writing this relationship to reflect a hydrologic balance, we have:

Inflows = Outflows +/- Change in Storage

Modifying this expression for the hydrologic characteristics of Pyramid Lake, yields:

ISW + IGW + P = OSW +/- [Change] S

where the elements of inflow are: ISW = surface water inflows from the Truckee River; IGW = ground water inflows, which may be considered as negligible; and P = lake-surface precipitation. The elements of outflow are: OSW = surface water outflow which is, of course, equal to zero for a terminus lake; E = lake-surface evaporation; and [Change] S represents the change in Pyramid Lake's storage, i.e., change in lake volume associated with the water budget period. Disregarding ground water inflows and setting OSW = 0, yields:

ISW + P = E +/- [Change] S

Using figures developed by the Pyramid Lake Task Force, a group formed in July 1969 to study the problems associated with Pyramid Lake's recession (and using 40 years of record from 1929-1969), we have ISW = 250,000 acre-feet per year; P = 55,000 acre-feet per year; and a lake evaporation rate of E = 440,000 acre-feet per year,(86) yielding a (balanced) water budget of:

250,000 + 55,000 = 440,000 - 135,000

Consequently, under this scenario of assumed no ground water inflows and no surface water outflows, this task force found that during this period of record Pyramid Lake sustained an average water budget deficit (-[Change] S) of 135,000 acre-feet per year.

One major problem with this form of analysis has been that, unlike Lake Tahoe, Pyramid Lake's surface elevation has varied widely over recent history. While variations of Lake Tahoe have typically been within a more or less six-foot range from its natural rim (6,223.0 feet MSL) to its upper legal limit (6,229.1 feet MSL), surface elevation variations of Pyramid Lake have been considerably greater. For example, from 1909 to 1968, the lake level declined from an altitude of 3,869 feet MSL to 3,789 feet MSL, corresponding to a drop of 80 feet in 59 years.(87) These figures translate into a change of lake volume from 30,440,00 acre-feet in 1909 to 20,500,000 acre-feet in 1968, a decline of 9,940,000 acre-feet, or 32.6 percent. More importantly for the development of a Pyramid Lake water budget, over this same period of time Pyramid Lake's surface area declined by 34,000 acres (53 square miles), or 24 percent, from 142,100 acres (222 square miles) in 1909 to 108,000 acres (169 square miles) in 1968.

Such wide variations in lake surface area have particularly dramatic effects on lake surface precipitation and especially evaporation. For example, in 1909, using current measures for this area of lake surface evaporation (4.2 feet, or 48.24 inches per year) and precipitation (0.63 feet, or 7.53 inches per year), the lake's annual surface evaporation would have been 571,242 acre-feet in 1909 versus 434,160 acre-feet in 1968. Similarly, Pyramid Lake's annual lake-surface precipitation would have been 89,168 acre-feet in 1909 as compared to 67,770 acre-feet in 1968. Consequently, over this period of time, the lake's water budget deficit, based merely on the change in surface area and its effects on evaporation and precipitation, would have declined by 137,082 acre-feet (from reduced surface evaporation) and concurrently increased by 21,398 acre-feet (from reduced surface precipitation), resulting in a net water budget reduction for Pyramid Lake of 115,684 acre-feet (137,082 acre-feet minus 21,398 acre-feet).

Consequently, any determination of a water budget for Pyramid Lake would have to take into account the extreme variations in surface elevation, and particularly changes in lake surface area. As a terminus location for the Truckee River Basin, these variable hydrologic conditions were true, although to a lesser degree, in the late 1800's when all flows in the Truckee River and into Pyramid Lake were essentially "natural." Records of King (1878)(88) and Russell (1885),(89) indicated that Pyramid Lake covered an estimated 140,000 acres (219 square miles), equating to a surface elevation of 3,862.5 feet MSL, and its surface elevation typically varied up to 20 feet during the year. This surface area indicates a rate of evaporation of 562,800 acre-feet per year, lake surface precipitation of 87,850 acre-feet per year, and, for an overall lake balance, i.e., S = 0, approximately 474,950 acre-feet of annual required Truckee River inflows.

Similarly, in order to attain and maintain a surface elevation in Pyramid Lake of 3,850 feet MSL (assuming the lake is currently at that level), we would need sufficient Truckee River inflows to cover the evaporation loss of approximately 540,000 acre-feet per year, less 84,000 acre-feet in lake surface precipitation, or, total Truckee River annual inflows equal to approximately 456,000 acre-feet per year. From Table 4--Selected Truckee River Runoff and Rates of Flow, it may seen that for the entire period of record for the Nixon USGS gage of 1958 to the present, inflows to Pyramid Lake have averaged 362,710 acre-feet per year, over 93,000 acre-feet less than those inflows required to maintain a surface elevation of 3,850 feet MSL. Even using the period since 1967, which corresponds to the year after which Truckee River diversions at Derby Dam were no longer allowed for power-only generation at Lahontan Dam, total inflows to Pyramid Lake have averaged 421,100 acre-feet per year. This rate of inflow would be sufficient to maintain Pyramid Lake at a level of nearly 3,831 feet MSL. On the other hand, based on the highly variable hydrology of this region, as a result of the flood of 1997 and continued precautionary discharges from upstream reservoirs, over the time period of December 4, 1996, to February 4, 1997, Pyramid Lake rose from a surface elevation of 3,800.00 feet MSL to 3,805.28 feet MSL.(90) This corresponds to a new lake volume of approximately 22,310,000 acre-feet, an increase of 590,000 acre-feet since December 4, 1996. The lake's surface area increased by some 1,784 acres (2.8 square miles) to 113,084 acres (176.7 square miles).

Pyramid Lake, Lake Fluctuations, and Climatic Changes

Pyramid Lake, as well as Walker Lake, which is located approximately 78 miles south and southeast of Pyramid Lake in the Walker River Basin, represent the last remaining major lake remnants of Ice Age Lake Lahontan. This ancient lake covered a highly irregular area throughout much of northwestern Nevada as recently as 12,500 years ago and experienced a number of fluctuations in its extent over the last 360,000 years. The importance of this lake's fluctuations lies in the corresponding climatic conditions that fostered its existence. Equally important, however, are the changes in those climatic conditions that led to its rapid ascensions and descensions and, during intervening periods, the complete desiccation (drying up) of some of its major basins, to include, it is believed, all but Pyramid Lake itself, which constituted the lowest point occupied by Lake Lahontan. Core samples taken of Pyramid Lake's lake bottom do not indicate a brine concentration, therefore suggesting that throughout Lake Lahontan's existence this lake remained in existence, although it was periodically severely restricted in size.(91)

Lake Lahontan was fed by the Truckee, Carson, Walker, Humboldt, Susan, and Quinn rivers. Lake Lahontan's extent consisted of seven major sub-basins in northwestern Nevada to include: (1) Smoke Creek/Black Rock Desert; (2) Carson Desert; (3) Buena Vista; (4) Walker Lake; (5) Pyramid Lake; (6) Winnemucca Dry Lake; and (7) Honey Lake. Associated with each of these basins was a primary "sill," defined as the lowest point on the divide between adjoining basins. The sills were important because only at water elevations above these threshold levels would the waters of Lake Lahontan, originating in the basin's lowest point--Pyramid Lake--spill over into these adjacent basins. These sills include (listed respectively according to sub-basin numbers above): (1) Pronto and Emerson Pass; (2) Darwin Pass; (3) Chocolate; (4) Adrian Pass (Valley); (5) none (Pyramid Lake was Lake Lahontan's lowest point in the basin); (6) Mud [Winnemucca] Lake Slough; and (7) Astor Pass.(92)

It was only at lake surface elevations above approximately 4,294 feet that all the basins of Lake Lahontan were joined into one continuous lake. This particular elevation represented the highest point within the Adrian Valley, a narrow pass, almost 10 miles in length, connecting the Carson River Basin to the north with the Walker River Basin to the south. Waters from an ascending Lake Lahontan flowed west up Dayton Valley in the lower Carson River basin and then south through the Adrian Valley and into the Walker River Basin. Once Lake Lahontan's waters emerged from the Adrian Valley, they raced down Campbell Valley to fill Walker Lake and the Walker Lake sub-basin and continued southward to beyond present-day town of Hawthorne in Mineral County, Nevada. Once the lower Walker River Basin was filed, waters then flowed up Mason Valley to the present-day location of the City of Yerington located in Lyon County, Nevada.

Extensive evidence based on sophisticated X-ray diffraction petrographic and radiocarbon analyses, as well as detailed analysis of Walker Lake's lakebed core samples, indicates that Lake Lahontan and its various hydrographic sub-basins have been subject to extensive fluctuations over the last 40,000 years, and that most of the sub-basins, with the possible exception of the basin's lowest point, Pyramid Lake, have desiccated on numerous occasions. This apparent repetitive cycle of ascension and descension, lake expansion and lake desiccation, and pluvial (wet) and inter-pluvial (dry) periods, has important implications on our own time period and the present hydrographic cycle, climatic conditions, and our expectations of natural versus man-caused changes within the various hydrologic basins in western Nevada.

As a general indication of climatic conditions within the Great Basin, evidence shows that between 15,000-13,500 years ago, Lake Lahontan went through a peaking enlargement (maximum stage), attaining a surface elevation of approximately 4,380 feet MSL,(93) a surface area of approximately 8,600 square miles,(94) and all of its sub-basins were connected. Lake Lahontan's last highstand occurred some 12,500 years ago. Between 11,000 and 10,000 years ago, climatic conditions again changed dramatically and the region entered what may be an inter-pluvial period. Lake Lahontan's surface level fell to approximately 3,871 feet, an elevation equivalent to that which existed in Pyramid Lake during the early 1880's. Warm and arid conditions have since prevailed throughout the Great Basin from approximately 10,000 years ago to the present.(95)


Return to Truckee River Chronology Index


Notes to Part I:


1. Lower Truckee River, Nevada Reconnaissance Report, U.S. Army Corps of Engineers, Sacramento District, July 1995, page 2-17. According to the U.S. Geological Survey, this total basin drainage area is 2,730 square miles (1,747,200 acres). This difference, 330 square miles (211,200 acres), cannot be explained by the USGS's exclusion of the Lake Tahoe Basin's 506 square miles (323,840 acres). [See Water Resources Data, Nevada, Water Year 1994, U.S. Geological Survey Water-Data Report NV-94-1, Nevada District Office, Water Resources Division, U.S. Geological Survey, U.S. Department of the Interior, Carson City, Nevada, 1995, page 314.]
2. A "terminal lake" is defined as a lake without an outlet.
3. Nevada Hydrographic Basin Statistical, Office of the State Engineer, Nevada Division of Water Resources and Nevada Division of WaterPlanning, Department of Conservation and Natural Resources, Carson City, Nevada, 1988. Also see Houghton, Samuel G., A Trace of Desert Waters: The Great Basin Story, University of Nevada Press, Reno, Nevada, 1994, page 61.
4. TRUCKEE RIVER ATLAS, Department of Water Resources, The Resources Agency, State of California, June 1991, page 11.
5. Houghton, op. cit., page 61.
6. Although this interstate compact was never ratified by Congress, its terms have been enforced through individual state legislation. California legislation is contained in Chapter 1480, California Statutes 1970; Nevada legislation is contained in Nevada Revised Statutes (NRS) 538.600. [See California-Nevada Interstate Compact Between the State of California and Nevada, Ratified by [the] State of California, September 19, 1970 (Chapter 1480, California Statutes 1970), Ratified by [the] State of Nevada, March 5, 1971 (Nevada Revised Statutes 538.600), Congressional Consent Pending, April 25, 1971.]
7. Wilds, Leah, J., Danny A. Gonzales, and Glen S. Krutz, "Reclamation and the Politics of Change: Rights Settlement Act of 1990," Nevada Historical Society Quarterly, Volume 37, Number 3, Fall 1994, Reno, Nevada, pages 180-181.
8. California-Nevada Interstate Compact Between the State of California and Nevada, Ratified by [the] State of California, September 19, 1970 (Chapter 1480, California Statutes 1970), Ratified by [the] State of Nevada, March 5, 1971 (Nevada Revised Statutes 538.600), Congressional Consent Pending, April 25, 1971, page 12.
9. The U.S. Geological Survey (USGS) and the Nevada Division of Water Resources, Department of Conservation and Natural Resources, have divided the state into discrete hydrologic units for WaterPlanning and management purposes. These have been identified as 232 Hydrographic Areas (256 areas and sub-areas, combined) within 14 major Hydrographic Regions or Basins. These 14 Nevada Hydrographic Regions (Basins) are (areas are for Nevada portions only): (1) Northwest Region--Covers 3,073 square miles (1,966,080 acres) of northern Washoe and Humboldt counties and encompasses 16 hydrographic areas; (2) Black Rock Desert Region--Covers 8,632 square miles (5,524,480 acres) of parts of Washoe, Humboldt, and Pershing counties and includes 17 valleys (hydrographic areas), two of which are divided into two sub-areas each; (3) Snake River Basin--Covers 5,230 square miles (3,347,200 acres) in parts of Elko and Humboldt counties to include eight hydrographic areas; (4) Humboldt River Basin--Covers over 16,843 square miles (10,779,520 acres) in parts of eight counties--Elko, White Pine, Eureka, Humboldt, Lander, Nye, Pershing, and Churchill--and the largest stream (Humboldt River) wholly within Nevada. This basin contains 34 hydrographic areas and one sub-area; (5) West Central Region--Covers 1,656 square miles (1,059,840 acres) and includes parts of Pershing, Lyon, and Churchill counties and comprises five hydrographic areas; (6) Truckee River Basin--Encompasses 2,300 square miles (1,472,000 acres) containing parts of Washoe, Pershing, Douglas, Carson City, and Storey counties comprising 12 hydrographic areas; (7) Western Region--Covers 577 square miles (369,280 acres) and is wholly contained in Washoe County and contains nine valleys (hydrographic areas) one of which is divided into two sub-areas and another divided into one sub-area; (8) Carson River Basin--Covers 3,519 square miles (2,252,160 acres) and includes parts of six counties--Douglas, Carson City, Lyon, Storey, Churchill, and Pershing--containing five hydrographic areas and one sub-area along the Carson River and its tributaries; (9) Walker River Basin--Covers 3,048 square miles (1,949,440 acres) of Mineral, Lyon, and Douglas counties including five hydrographic areas, one of which has been divided into three sub-areas; (10) Central Region--By far the largest hydrographic region in Nevada covering 46,783 square miles (29,941,120 acres) in 13 counties--Nye, Elko, White Pine, Lincoln, Clark, Humboldt, Pershing, Churchill, Lander, Eureka, Lyon, Mineral, and Esmeralda. This region includes 78 valleys (hydrographic areas), 10 of which are divided into two sub-areas and one into three sub-areas; (11) Great Salt Lake Basin--Covers 3,807 square miles (2,436,480 acres) of the easternmost portions of Elko, White Pine, and Lincoln counties. It consists of eight hydrographic areas, one of which is divided into four sub-areas; (12) Escalante Desert Basin--This basin covers a large area in Utah but only a very small part of it is in Lincoln County--106 square miles (67,480 acres)--and is made up of only one hydrographic area; (13) Colorado River Basin--Covers 12,376 square miles (7,920,640 acres) including parts of Clark, Lincoln, Nye, and White Pine counties and is divided into 27 hydrographic areas; (14) Death Valley Basin--Covers 2,593 square miles (1,659,520 acres) of Nye and Esmeralda counties including eight hydrographic areas, one of which has been divided into two sub-areas. [See Horton, Gary A., WATER WORDS DICTIONARY, Nevada Division of WaterPlanning, Department of Conservation and Natural Resources, Carson City, Nevada.]
10. The word "terminus" refers to the location of a stream's final destination, as the terminus of a river system being a "terminal lake."
11. Due to the Lake Tahoe Dam located at Tahoe City, California, Lake Tahoe is allowed to vary its surface elevation up to a legal maximum of 6,229.1 feet MSL (Truckee River Agreement), with waters stored in the top 6.1 feet (between 6,223.0 feet MSL and 6,229.1 feet MSL) used to satisfy downstream water rights (i.e., Floriston rates and Orr Ditch Decree rights). Gage heights for Lake Tahoe are based on the U.S. Bureau of Reclamation (USBR) datum (reference level) of 6,220.00 feet above mean sea level (MSL). The corresponding National Geodetic Vertical Datum of 1929 is 6,218.86 feet MSL. The USBR datum is used for Lake Tahoe surface elevation measurements because that datum is used as the official reference point by all local, state, and federal agencies. [Water Resources Data, Nevada, Water Year, U.S. Geological Survey Water-Data Report, Nevada District Office, Water Resources Division, U.S. Geological Survey, U.S. Department of the Interior, Carson City, Nevada.]
12. Rush, F. Eugene, "Water Resources-Information Series Report 17: Bathymetric Reconnaissance of Lake Tahoe, Nevada and California," Prepared cooperatively by the Geological Survey, U.S. Department of the Interior and the Division of Water Resources, Department of Conservation and Natural Resources, State of Nevada, Carson City, Nevada, 1973.
13. TRUCKEE RIVER ATLAS, op. cit., page 8.
14. Other references to Lake Tahoe's dimensions use a lake surface elevation of 6,229.0 feet MSL, providing for a surface area of approximately 194 square miles (124,160 acres), a maximum depth of 1,646 feet, and a total volume of approximately 125 million acre-feet. [See Rush, op. cit.]
15. This figure is based on a Nevada total surface area of 110,561 square miles, or 70,758,757 acres.
16. Rush, op. cit. Another source presented a greater evaporation rate of 375,000 acre-feet per year. [See TRUCKEE RIVER ATLAS, op. cit., pages 15-16.]
17. Houghton, op. cit., page 52.
18. Hyne, N.J., et al., Quaternary History of Lake Tahoe, California-Nevada: Geological Society America Bulletin, Volume 83, 1972, page 1435.
19. Houghton, op. cit., page 53. Also see Table 2 and the discussion of the development of a water budget for Lake Tahoe.
20. Rush, op. cit.
21. This analysis was developed using the presentation in Rush (op. cit.), which covered the hydrologic period of record from 1901 through 1971. Different or more recent figures which would affect this water budget include Truckee River outflows measured at Tahoe City, California, which have averaged 162,890 acre-feet per year over the 1909-1994 period of record (Water Resources Data--Nevada, op. cit.), a lake surface evaporation rate of 375,000 acre-feet per year as presented in the TRUCKEE RIVER ATLAS (op. cit. pages 15-16), and diversions out of the Lake Tahoe Basin totaling a maximum level of 34,000 acre-feet per year as permitted under the California-Nevada Interstate Compact of which 23,000 acre-feet annually is allocated to the State of California and 11,000 acre-feet annually is allocated to the State of Nevada (California-Nevada Interstate Compact Between the State of California and Nevada, op. cit., page 12).
22. The precipitation and evaporation rates (inches per year) are based on Rush's (op. cit.) estimates of a total lake surface area of 194 square miles (124,160 acres), corresponding to a lake surface elevation of 6,229.0 feet MSL, and corresponding levels of precipitation (220,000 acre-feet per year) and evaporation (350,000 acre-feet per year).
23. Despite having won "numerous" awards for its innovative methods with respect to wastewater treatment, the Tahoe-Truckee sewage treatment plant (Tahoe-Truckee Sanitation Agency) recently (June 1996) concluded a $31,275 settlement with Nevada County, California. The settlement was the result of an investigation by the Nevada County District Attorney's Office pertaining to a spill of hydrochloric acid at the plant on April 4, 1995. The spill sent a toxic cloud of acid fumes into the air, causing several minor injuries and forcing the evacuation of about 200 people from nearby offices and homes. Both hydrochloric and sulfuric acids are used at the plant in the effluent-treatment process and for cleaning purposes. [See Reno Gazette-Journal, June 13, 1996, page 2D.]
24. In addition to the town of Truckee, the Truckee sewage disposal plant also receives effluent transported out of the Lake Tahoe Basin from the North Tahoe Public Utility District and the Tahoe City Public Utility District. These entities service the sewage collection needs of the west side of Lake Tahoe from the service area of the South Tahoe Public Utility District (STPUD) north to the California-Nevada state line at Crystal Bay, Nevada.
25. Houghton, op. cit., page 62.
26. Joplin, Maureen (Geologist), and Hal Fiore (Hydrologist), Gray Creek Watershed Monitoring Project, United States Department of Agriculture, Forest Service, April 4, 1995, page 5, and Reno Gazette-Journal, July 22, 1995, page 1.
27. Townley, John M., The Truckee Basin Fishery, 1844-1944, Water Resources Center Publication 43008, Desert Research Institute, University of Nevada System, November 1980, page 51.
28. Of possible significance in the persistence of its operations was the fact that the FP&PC was owned by the Fleishhacker banking and investment firm of San Francisco, an entity which also controlled the Reno Water, Land and Light Company. Of particular interest is that Mr. Mortimer Fleishhacker served as President of the Truckee River General Electric Company in the early 1900's. [See Townley, The Truckee Basin Fishery, op. cit., page 50, and Pipe & Wire: A Historical Profile of Sierra Pacific Power Company, Sierra Pacific Power Company, Reno, Nevada, 1977, page 16.]
29. Lake Winnemucca last went dry in 1938 due to insufficient Truckee River inflows. Today, due to the construction of a roadbed, there exists virtually no chance of Truckee River waters reaching this location. Even so, during particularly wet years, an extensive pool of relatively shallow water does typically form in spring and early summer at the northern end of this expanse, fed solely by precipitation and local surface and ground water inflows.
30. Judson, Dean H., Ph.D.,and Brad Ramiriz, M.S., Nevada County Population Estimates by Race, Sex, and Hispanic Origin: 1995 Estimates, Projections and Review of Methods, Office of the State Demographer, Bureau of Business and Economic Research, College of Business Administration, University of Nevada, Reno.
31. These are believed to have occurred at approximately 65,000, 45,000, 30,000, and as recently as 12,500 years ago. [See Houghton, op. cit., page 63, and Benson, Larry V., "Preliminary Paleolimnologic Data for the Walker Lake Sub-Basin, California and Nevada," Water Resources Investigations Report 87-4258, U.S. Geological Survey, U.S. Department of the Interior, Denver, Colorado, 1988, page 2.]
32. This doctrine not only applies to Indian reservations, but to all forms of federal "reservations," including National Parks, National Forests, National Recreation Areas, National Monuments, National Wildlife Refuges, and the like.
33. For examples of the economic and cultural importance of the Pyramid Lake and lower Truckee River fisheries to the Pyramid Lake Paiute Indian Tribe, see chronology entries in Part II under January 31, 1864, March 25, 1865, March 29, 1867, January 10, 1868, March 18, 1871, August 16, 1873, February 16, 1875, January 20, 1877, August 30, 1880, August 31, 1881, August 29, 1882, August 11, 1883, August 20, 1885, August 17, 1891, September 28, 1896, and July 25, 1899.
34. Townley, John M., The Truckee Basin Fishery, op. cit., page 39.
35. The last spawning run of the Pyramid Lake cutthroat trout was reported to have occurred in 1938, and this sub-species was reportedly extinct by 1940 or shortly thereafter. [See Wilds, op. cit., page 181.]
36. Both of these facilities were part of the U.S. Bureau of Reclamation's Washoe Project, first proposed in 1954 to improve flood control on the Truckee River. The Washoe Project contained proposals for both the Truckee River Basin and the Carson River Basin. Those facilities proposed and eventually constructed for the Truckee River Basin included Prosser Creek Dam and Reservoir (constructed in 1962 and located on Prosser Creek), Stampede Dam and Reservoir (constructed in 1970 and located on the Little Truckee River upstream from Boca Reservoir), and Marble Bluff Dam and Pyramid Lake Fishway (constructed in 1975 and located on the Pyramid Lake Paiute Indian Reservation). None of the projects proposed for the Carson River Basin were ever funded or constructed. [See Washoe Project Sheet Map and Fact Sheet, United States Department of the Interior, Bureau of Reclamation, Nevada-California, Mid-Pacific Region, Map number 320-208-35, January 1956 and April 1991.]
37. Lake Lahontan was named after Baron Louis Armand de Lom d'Arce de la Hontan, born in 1666, who explored French Canada from 1683 to 1693, but never came within 1,000 miles of the ancient lake site. The naming of the lake was given credit to Clarence King, a noted geologist of the Great Basin, in 1878, although in all probability it was Arnold Hague who first linked the name with the Pluvial lake in 1877 in an article he wrote on the Truckee River region. [See Houghton, op. cit., page 74.]
38. Geological studies have shown that Lake Lahontan underwent several Pluvial oscillations which included at least three peaking enlargements (highstands) occurring at about 65,000, 45,000, and 30,000 years ago, with a maximum surface height of approximately 4,380 feet and a depth of at least 886 feet at Pyramid Lake, the lowest point in the system. Two prolonged stillstands took place at 3,873 feet and 3,855 feet, lake surface elevations not much higher than the current near-3,800 foot level of Pyramid Lake. [See Houghton, op. cit., page 73.] Benson ["Preliminary Paleolimnologic Data for the Walker Lake Sub-Basin, California and Nevada," op. cit., page 2] found evidence of other Lake Lahontan highstands, the latest occurring as recently as 12,500 years ago.
39. Houghton, op. cit., page 76.
40. Pyramid Lake Task Force Final Report, December 1971, page 1.
41. Ibid., page vi.
42. From surface-elevation data obtained from the U.S. Geological Survey, Water Resources Division, Carson City, Nevada.
43. Based on April 1996 lake volume of approximately 21,500,000 acre-feet and TDS concentration of 5,200 milligrams per liter printed in 1980 edition of Nevada Water Facts, Nevada Division of WaterPlanning, Department of Conservation and Natural Resources, Carson City, Nevada, and estimated lake volume of 20,900,000 acre-feet.
44. This estimated is based on volume and surface elevation tables by Harris, 1970.
45. Phreatophytes are perennial plants which are very deeply rooted, deriving their water from a more or less permanent, subsurface water supply; they are thus not dependent upon annual precipitation for survival. [See Horton, WATER WORDS DICTIONARY, op. cit.]
46. The Truckee River USGS gaging station located immediately below (1,500 feet) Derby Dam [gaging station 10351600] does not reflect return flows from the Truckee Canal which are spilled back into the Truckee River above Wadsworth from the Gilpin Spill and the Paiute Spill. These spills occur before the first Truckee Canal USGS gaging station [10351300] and are therefore not reflected in that measurement as Truckee Canal diversions. Anecdotal evidence indicates that these return flows have, at times, been substantial. [Personal communication with Norm Saake, Statewide Waterfowl Specialist, Game Bureau, Nevada Division of Wildlife (NDOW), Department of Conservation and Natural Resources, Fallon, Nevada, May 1996, and Al Olson, WaterPlanning and Operations, Lahontan Basin Projects Office, U.S. Bureau of Reclamation, Carson City, Nevada.]
47. The fact that these two amounts, the percentage of Truckee River flow into Pyramid Lake (70.9 percent) and the Truckee River flow diverted down the Truckee Canal (31.4 percent) exceed 100 percent is based on both the different periods of record (1973-1994 for Farad and the Truckee Canal gaging stations and 1958-1994 for the Nixon gaging station) and the effects of the high water years of 1982, 1983, 1984, and 1986, particularly, which distorted flow rates and total runoff volumes. If average year runoff volumes are computed for the Farad gaging station, the Truckee River at Nixon (Pyramid Lake), and the Truckee Canal at Wadsworth, specifically omitting these years, then the Farad runoff averaged 400,673 acre-feet per year, the Nixon Pyramid Lake inflow averaged 202,608 acre-feet per year (50.6 percent of the Farad flow), and the Truckee Canal flow at Wadsworth averaged 183,434 acre-feet per year (45.8 percent of the Farad flow).
48. This figure represents a measure from the "highest high" (i.e., maximum surface elevation recorded in 1891) to the "lowest low" (i.e., the minimum surface elevation recorded in 1967). The highest surface elevation for Pyramid Lake recorded in 1967 was 3,788.9 feet MSL, making this decline equal to 89.3 feet. Data on Pyramid Lake's surface water elevations was obtained from the U.S. Geological Survey (USGS), Water Resources Division, Carson City, Nevada.
49. Much has been written on the high TDS concentrations in Walker Lake, located in the Walker Lake Basin, and the degradation of that lake's fishery as TDS levels approximate 13,000 milligrams per liter (see Horton, Gary A., Walker River Chronology, Nevada Division of WaterPlanning, June 1996). However, due to Pyramid Lake's considerably greater salt loading (volume of salts in the water), if Pyramid Lake was reduced in volume from its present 21,605,000 acre-feet (April 1996) to that volume of Walker Lake (approximately 2,000,000 acre-feet), TDS concentrations in Pyramid Lake would rise from the current 5,100 mg/l to over 55,000 mg/l, making Pyramid Lake considerably saltier than sea water (35,000 mg/l) and killing all the fish in the lake.
50. Frémont, John Charles, Report of the Exploring Expedition to the Rocky Mountains, 1842, and to Oregon and North California, 1843-44, Washington, D.C., Gales & Seaton, 1845.
51. The statement made her is based on an overall water budget for Pyramid Lake consisting of a measure of inflows, outflows, and change in storage (total lake volume). Disregarding as negligible local surface water and groundwater inflows, lake inflows consist primarily of Truckee River inflows (356,920 acre-feet per year, 1967-1994), and lake surface precipitation (55,000 acre-feet per year, estimated over the period 1929-1969). The primary outflow consists of lake surface evaporation, amounting to approximately 440,000 acre-feet per year (4.1 feet per year, estimated over the period 1929-1969). These figures yield an annual water deficit (i.e., decline in volume) for Pyramid Lake of approximately 30,000 acre-feet per year. This statement, however, may be criticized based on differing "periods of record." There is little question that based on lake surface elevation declines, Pyramid Lake experienced a deficit during the period of the early 1900's through 1967. However, more recent periods of record, e.g., 1967-present and especially 1988-present, may well present a different picture based on reduced surface area (affecting primarily evaporation) and reduced diversions at Derby Dam.
52. Saake, op. cit.
53. Tabulated by Sierra Hydrotech from Truckee-Carson Irrigation District (TCID) diversion records.
54. This elimination of the use of water for single-purpose power generation within the project was part of a "Bureau of Reclamation 9 Point 'Package' Proposal" supposedly negotiated between the USBR and TCID. In brief, these points included: (1) Operation of TCID facilities so as to maximize use of Carson River flows and minimize use of the Truckee River flows; (2) Furnish TCID for irrigation requirements 406,000 acre-feet annually; (3) Freeze TCID water rights at the present level of approximately 74,500 acres; (4) Eliminate the use of water for single-purpose power generation; (5) Withdraw from TCID custody of the 64-acre tract at Lake Tahoe and divert it to public use with no direct remuneration to TCID; (6) TCID to complete payment [of project facilities] in accordance with its existing contractual obligation; (7) To assist in accomplishments of objectives (1) and (2), and in consideration of points (3), (4), (5), and (9), the U.S. will undertake certain rehabilitation programs on a non-reimbursable basis [with a total estimated cost of approximately $3.5 million]; (8) Re-negotiate the three party agreement for the Stillwater Wildlife Management Area in accordance with recent discussions between TCID and USFWS [this action would involve retention of custody of the land by TCID and an agreement on a percentage split of drainage and return flows to the Stillwater area and the Carson Lake [and] Pasture to the south; and (9) Revoke custody of fringe areas of custodial land which are of little value to TCID. [According to correspondence provided by Truckee-Carson Irrigation District, June 3, 1996, this agreement was sent to Washington, D.C., but was never ratified. Nevertheless, TCID "was required to comply with its provisions including the repair of the Truckee Canal which was to be partially reimbursed by the federal government but was not."]
55. See Table 5, Selected Truckee River and Truckee Canal Flows, for a more complete analysis.
56. Figure covers the period of record 1967-1994. [See Water Resources Data, Nevada, Water Year 1994, U.S. Geological Survey Water-Data Report NV-94-1, Nevada District Office, Water Resources Division, U.S. Geological Survey, U.S. Department of the Interior, Carson City, Nevada, 1995, page 513.]
57. This is the right specified in the Orr Ditch Decree; however, the Truckee Canal's nominal capacity without risk of spilling is only approximately 900 cfs. [Written communication, R. Michael Turnipseed, Nevada State Engineer, Division of Water Resources, Department of Conservation and Natural Resources, Carson City, Nevada, March 15, 1996.]
58. Horton, WATER WORDS DICTIONARY, op. cit.
59. The Alpine Decree represented the Federal Court adjudication of the relative water rights on the Carson River which is the primary regulatory control of Carson River operations today. The decree is administered in the field by a watermaster appointed by the federal district court. The decree, finally issued on October 28, 1980 after initial litigation was begun in 1935, established the respective water rights (to surface water only) of the parties to the original lawsuit, both in California and Nevada to Carson River water. The decree did not make an interstate allocation of the Carson River between California and Nevada; it only quantified individual water rights. Neither state was a party to the decree. In addition to Carson River surface water rights, it also established the rights to reservoir storage in the high alpine reservoirs and confirmed the historical practice of operating the river on rotation, so that irrigators with more junior priorities could be served as long as possible. These upper alpine reservoirs were permitted to fill out of priority order, in accordance with historical practice. The decree also specifically recognized riparian water rights in California (as distinguished from the quantified appropriative water rights used in Nevada). For purposes of water distribution, the Carson River and its east and west forks, were divided into eight (8) segments and when the river went into regulation (i.e., there was not enough water in the Upper Carson River to serve the most junior priority) each segment of the river was to be administered autonomously. Duties of water were set forth for various locations according to bench land and bottom land designations. For lands in the Newlands Irrigation Project (i.e., below Lahontan Dam) in Churchill County near Fallon, the Alpine Decree provided for an annual net consumptive use of surface water for irrigation of 2.99 acre-feet per acre and a maximum water duty of 4.5 acre-feet per acre for water-righted bench lands and 3.5 acre-feet per acre for water-righted bottom lands delivered to the land. For lands above the Newlands Project (i.e., above Lahontan Reservoir), the net consumptive water use was set at 2.5 acre-feet per acre with water duties of 4.5 acre-feet per acre diverted to the canal for bottom lands, 6.0 acre-feet per acre diverted to the canal for the alluvial fan lands and 9.0 acre-feet per acre diverted to the canal for the bench lands. This annual net consumptive use, or crop water requirement, was based on the water duty of alfalfa as it is a dominant and the highest water-using crop grown in Nevada. While the Alpine Decree established water duties for bench and bottom lands throughout the Carson River Basin, it made no identification of those lands. The decree also granted landowners on the Newlands Project an appurtenant water right for the patented lands, effectively transferring water rights to these land holders individually. [See "Alpine Decree, Findings of Fact, Conclusions of Law, Tabulation and Administrative Provisions," United States of America v. Alpine Land & Reservoir Company, a Corporation, et al., Civil No. D-183 BRT [Bruce R. Thompson], Final Decree, United States Federal District Court for the District of Nevada, October 28, 1980.]
60. Horton, WATER WORDS DICTIONARY, op. cit.
61. The Tahoe-Prosser Exchange Agreement ("Agreement for Water Exchange Operations of Lake Tahoe and Prosser Creek Reservoir") was finalized in June 1959 and designated certain waters in Prosser Reservoir as "Tahoe Exchange Water." By this agreement, when waters were to be released from Lake Tahoe for a minimum instream flow (50 cfs winter; 70 cfs summer) and when such releases from Lake Tahoe were not necessary for Floriston rates due to normal flows elsewhere in the river, then an equal amount of water (exchange water) could be stored in Prosser Reservoir and used for releases at other times. [See A Study of Water Rights and Their Enforcement [in the] Lake Tahoe, Truckee and Carson River Basins, Prepared by Water Rights Study Group, Pyramid Lake Task Force, [for the] U.S. Department of the Interior, Office of the Solicitor, Sacramento Region, Sacramento, California, August 1971, pages 92-95.]
62. In addition to the South Tahoe Public Utility District (STPUD), sewage treatment and transfer of effluent out of the Lake Tahoe Basin is handled by two other utilities: The North Tahoe Public Utility District and the Tahoe City Public Utility District. These entities service the sewage collection needs of the west side of Lake Tahoe from the service area of the STPUD north to the California-Nevada state line at Crystal Bay, Nevada. Sewage is transported to the Tahoe-Truckee Sewage Treatment Plant at Truckee, California where it receives advanced tertiary treatment and then is infiltrated into the ground. Therefore, these waters remain within the Truckee River Basin.
63. Reno Gazette-Journal, April 30, 1996, page 3B.
64. Water Resources Data, Nevada, Water Year 1994, op. cit., page 513.
65. Data collected under contract by Sierra Hydrotech, a consultant who tabulated Truckee Canal diversions from the Federal Watermaster's gage for water years 1910-1966. This tabulation showed an average annual diversion of 239,700 acre-feet. [Olson, op. cit.]
66. According to testimony presented in the hearing on Application 9330, the capacity of the Truckee Canal is actually about 1,100 cfs; however, at that level it is dangerously close to overtopping and plugging. Consequently, nominally, they try to keep the diversion at around 900 cfs. [Turnipseed, op. cit.]
67. The water duty is defined as the total volume of irrigation water required to mature a particular type of crop. In stating the duty, the crop, and usually the location of the land in question, as well as the type of soil, are also considered. The water duty also includes consumptive use, evaporation and seepage from on-farm ditches and canals, and the water that is eventually returned to streams by percolation and surface runoff. [See Horton, WATER WORDS DICTIONARY, op. cit.]
68. De Bruyn, David, Potential Water Conservation Measures--Newlands Project, Prepared under the Request of the Special Assistant to the Secretary of the Interior on Matters Dealing with Public Law 101-618 [Negotiated Settlement], April 1992, page 23.
69. Horton, WATER WORDS DICTIONARY, op. cit.
70. According to the complaint, the recoupment figure was derived from: (1) 151,130 acre-feet of water diverted during the 15-year time frame that was sent to Lahontan Reservoir at the same time that water was being released [spilled] from Lahontan Dam as a precaution to prevent flooding; (2) 188,368 acre-feet of water that was diverted during the 15-year time frame in the winter months and stored in Lahontan Reservoir and then later spilled as precautionary releases and was over OCAP allowances; (3) 682,215 acre-feet of diversions made to Fallon farmers in excess to the 1973 OCAP limitation; (4) 32,253 acre-feet of excessive diversions to Fernley, Hazen, and Swingle Bench farmers; and (5) approximately 10,034 acre-feet in additional miscellaneous (unspecified) diversions. [Lahontan Valley News, Fallon, Nevada, December 12, 1995.]
71. Turnipseed, op. cit.
72. Reno Gazette-Journal, December 3, 1995, pages 1C and 4C.
73. Reno Gazette-Journal, December 12, 1995, page 2B, and Lahontan Valley News, Fallon, Nevada, December 12, 1995.
74. Reno Gazette-Journal, August 3, 1995, page 1B, and Olson, op. cit.
75. Turnipseed, op. cit., and Nevada Appeal, Carson City, Nevada, November 14, 1995, page A9.
76. Water right application file 9330, Office of the State Engineer, Nevada Division of Water Resources, Department of Conservation and Natural Resources, Carson City, Nevada.
77. CARSON RIVER ATLAS, Department of Water Resources, The Resources Agency, State of California, Sacramento, California, December 1991, pages 95-96.
78. Public Law 101-618, Section 209.(a)(1)(B).
79. Horton, WATER WORDS DICTIONARY, op. cit.
80. On November 1, 1995, by agreement between Sierra Pacific Power Company (SPPCo) and the Pyramid Lake Paiute Indian Tribe, this reduced rate of 350 cfs for a lake-surface level between 6,225.25 feet MSL and 6,226.0 feet MSL was dropped to 300 cfs with the estimated difference of 20,000-30,000 acre-feet to be stored in Stampede Reservoir and used for spawning runs of Pyramid Lake's endangered and threatened fish species. This agreement also gave SPPCo an increased storage right of 39,500 acre-feet in Stampede Reservoir. [Reno Gazette-Journal, November 2, 1995, pages 1B and 4B.]
81. Ibid.
82. TRUCKEE RIVER ATLAS, op. cit., page 54.
83. Horton, WATER WORDS DICTIONARY, op. cit.
84. These figures have been calculated from the bathymetry of Pyramid Lake found in Harris, op. cit.
85. The Lake Tahoe Basin snow pack water content figures produced an average of 99 percent, a standard deviation (variability about this mean or average value) of 50 percent, and t-value (the series mean divided by the standard deviation) of 2.00. The Truckee River Basin figures produced an average of 102 percent, standard deviation of 51 percent, and a t-value of 1.98. Both these t-value figures indicate that the period average approximated the true mean (100 percent) at a level of statistical confidence of approximately 90 percent.
86. Pyramid Lake Task Force Final Report, December 1971, page I.
87. Harris, E.E., "Reconnaissance Bathymetry of Pyramid Lake, Washoe County, Nevada," Water Resources-Information Series, Report 20, Prepared Cooperatively by the Geological Survey, U.S. Department of the Interior, and the Division of Water Resources, Department of Conservation and Natural Resources, State of Nevada, Carson City, Nevada, 1974.
88. King, Clarence, United States Geological Explorations of the Fortieth Parallel, Volume 1, Systematic Geology, U.S. Government Printing Office, Washington, D.C., 1878.
89. Russell, I.C., Geological History of Lake Lahontan, A Quaternary Lake of Northwestern Nevada, U.S. Geological Survey Monograph 11, 1885.
90. U.S. Bureau of Reclamation, Lahontan Basin Area Office, Carson City, Nevada.
91. Benson, Larry V., "Fluctuation in the Level of Pluvial Lake Lahontan During the Last 40,000 Years," Quaternary Research, Volume 9, Number 3, University of Washington, 1978, pages 314-315.
92. Benson, "Preliminary Paleolimnologic Data for the Walker Lake Sub-Basin, California and Nevada," op. cit., page 2.
93. Houghton, op. cit., page 73.
94. Benson, "Fluctuation in the Level of Pluvial Lake Lahontan During the Last 40,000 Years," op. cit., page 316.
95. Benson, "Preliminary Paleolimnologic Data for the Walker Lake Sub-Basin, California and Nevada," op. cit., page 1.


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