NPWRC :: Platte River Ecosystem Resources

Northern Prairie Wildlife Research Center

Appendices

Nebraska

Following are descriptions of fish and wildlife resources in 18 river reaches in Nebraska that have similar geographic relations and support similar riverine habitats.

This reach is a largely open channel bordered by riparian woodland. Selective clearing has enhanced wooded habitats in many areas by stimulating growth of the understory and increasing the amount of edge. Riparian woodland in the Platte River system has high value to white-tailed deer, wild turkey and great blue herons.

Although upstream development significantly reduced flows (Currier et al. 1985), mallards winter near Columbus and between North Bend and Gretna. From 1982 to 1987, an average of about 38,000 wintering mallards and 200 wintering Canada geese were present in January (NGPC, Lincoln, Nebraska, unpubl. data). Waterfowl hunting is extensive throughout this reach.

Bald eagles winter throughout most of the reach. Endangered interior least terns and threatened piping plovers nest in several locations along this river sreach. Whooping cranes are not known to use the area. The southern flying squirrel, a State listed threatened species, is probably present along the lower 20 to 40 miles of the Platte River.

The Platte River below the confluence of the Loup River has been identified by the NGPC as a highest value (Class I) fishery resource. Channel catfish, walleye, sauger, shovelnose sturgeon, and other fish are harvested from this reach. Paddlefish probably occur seasonally in the lower reach. The NGPC is currently conducting instream flow studies using the USFWS's Instream Flow Incremental Methodology (IFIM) to better determine the relationship between stream flows and fishery habitat in this reach.

The lake sturgeon and the pallid sturgeon, two State threatened species, occasionally inhabit the lower portion of the Platte River, although no collections have occurred recently. No other state or federally listed or candidate fish species are known to occur in this reach. The USFWS has designated this reach as having high value for wintering and migrating mallards and for channel catfish and shovelnose sturgeon.

Flows in this reach have been depleted by upstream developments; further development is anticipated. This reach is used by migrating waterfowl and waterfowl hunting is extensive throughout. Endangered least terns and threatened piping plovers nest on sandbars in the river. Whooping cranes have used this reach during migration.

The lower Loup River system was identified by the NGPC as a high value (Class I) fishery resource. Channel catfishes, carp, and forage fishes are the most predominant species in this reach. The USFWS has recognized the value of waterfowl and channel catfish in this reach.

Much of this reach was dewatered by upstream development; several new developments are proposed. Dewatering has eliminated flowing water during the summer in 30% of the years. Mallard, blue-winged teal, green-winged teal, northern pintail, gadwall, and American wigeon are some of the waterfowl species harvested. The lower 12 miles is a waterfowl wintering area. From 1982 to 1987, an average of about 1,500 mallards and 100 Canada geese were present in January (NGPC, Lincoln, Nebraska, unpubl. data). This reach is also used by waterfowl during spring migration. Canada geese, greater white-fronted geese, and snow geese are harvested throughout this reach. Whooping cranes are not known to use this reach; bald eagles use the area in winter. Least terns and piping plovers use sandpits in this reach for nesting.

This reach has a substantial (Class III) fishery. Channel catfishes, carp, and forage fishes are the most abundant species. When flows are adequate, fishes such as channel catfish and carp, reproduce in this reach. This reach has medium to high value to wintering and migrating mallards and to channel catfishes.

Platte River: Central Nebraska Public Power and Irrigation District's Johnson 2 Power Plant (J-2) Return to Chapman, Nebraska

Flows in this reach have been reduced by upstream diversions; additional diversions are proposed. This reach is an important waterfowl wintering area, primarily between the J-2 Return and Newark, Nebraska. From 1982 to 1987, about 20,000 mallards and 11,000 Canada geese wintered annually in this reach (NGPC, Lincoln, Nebraska, unpubl. data).

This reach is particularly important as a spring migration stopover area used greater white-fronted geese, particularly when the rainwater basins south of the river are dry or frozen. About 300,000 greater white-fronted geese (nearly 100% the mid-continent population) occupy this area. Unlike the fowl cholera-prone rainwater basins, the Platte River provides an almost disease-free environment.

About 80% of the global sandhill crane population stages each spring in this reach. About two-thirds of the global population uses the Platte River between Kearney and Grand Island for up to six weeks each year to store energy and nutrient reserves for the continued flight north. Some use of the river by sandhill cranes occurs in the fall, but the numbers are considerably lower.

Sandhill cranes choose river reaches with: 1) channels over 500 feet wide; 2) slow moving current; 3) barren sandbars that are located in a wide channel; and 4) isolation from human disturbance. The cumulative decrease in the total area of sandbars and open water occurring in this reach of the Platte River coincides with a decreased volume of stream discharge. Over 70% of the pre-settlement mean annual flow is diverted upstream for consumptive uses. Large areas of wet meadows, which provide food items containing essential amino acids and minerals, have been drained and converted to cropland.

State and federally listed threatened and endangered species which occur in this reach are the whooping crane, bald eagle, interior least tern, Eskimo curlew, peregrine falcon, piping plover, and western prairie-fringed orchid. The Aransas-Wood Buffalo flock of whooping cranes migrates through Nebraska twice annually. Whooping crane use has occurred downstream to near Phillips, Nebraska. Fifty-three miles of the Platte River and the immediately adjacent habitat from Lexington to near Shelton has been designated critical habitat for the whooping crane (USFWS 1978). Riverine roost sites occupied by whooping cranes are characterized by wide unobstructed channels, variable water depths, sand substrate, proximity to feeding sites, and isolation from human disturbance.

Bald eagles winter throughout this reach. Their distribution is determined primarily by the presence of open water. Least terns and piping plovers use the river and adjacent sandpits for nesting. Unvegetated sandbars in the channel provide nest sites for least terns and piping plovers; the birds forage primarily in adjacent reaches of the Platte River.

This reach is a substantial (Class III) fishery resource. Channel catfish and carp are two of the most abundant fishes. This reach has high habitat value for sandhill cranes, greater white-fronted geese, and is considered to be unique and irreplaceable (USFWS 1981).

Platte River from the Diversion near North Platte: Nebraska to the J-2 Return near Overton, Nebraska

This reach is about 70 miles long. The river channels are narrow and extensively encroached by woody vegetation. Stream flow reductions in this river reach were even greater than the reductions in the previous reach.

Some wintering habitat for waterfowl occurs throughout the reach. An average of about 8,000 mallards and 1,500 Canada geese wintered annually in this reach during 1982-87 (NGPC, Lincoln, Nebraska, unpubl. data). At least three great blue heron colonies exist in this river reach. Wintering bald eagles are fairly common during most years. Three sandpit complexes near Maxwell, Gothenburg, and Lexington are used for nesting by least terns and piping plovers.

This reach has been identified by the NGPC as a high priority (Class II) fishery. The channel catfish is the primary game fish, although walleye, largemouth bass, and white bass are caught. This reach has medium to high value to wintering and nesting mallards, great blue herons, and channel catfish.

Lake Maloney to the diversion below confluence of North and South Platte Rivers

This reach is immediately upstream of the previous reach and includes about three miles of canal, the lowermost three miles of the South Platte River, and the small impoundment area above the Central Nebraska Public Power and Irrigation District river diversion. The water supplies in Lake McConaughy and the South Platte River largely determine the quantity of discharge into this reach.

The canal is of little importance to wildlife resources. The river otter, a atate listed endangered species, has been observed at Lake Maloney and in the South Platte River. One confirmed and one probable sighting of a whooping crane were recorded in or near the area. Bald eagles winter in scattered locations throughout this reach; a bald eagle winter roost is about two miles below the diversion. At least one least tern nesting colony has been present since 1988 on a sandpit adjacent to the South Platte River. This reach has a high value (Class I) fishery. Walleye, channel catfish, smallmouth bass, and white bass make up the bulk of the sport fishery. The canal and the river reach are medium to high value habitat for walleye, smallmouth bass, and white bass.

The flow in this reach has been severely reduced by upstream development; more development is probable. Some waterfowl wintering areas exist in and near the riverine habitat. From 1982 to 1987, an average of about 2,000 mallards and 1,400 Canada geese were present in January (NGPC, Lincoln, Nebraska, unpubl. data). Bald eagles use this reach in winter.

The upper one-third of this reach supports a limited fishery (Class IV); the remainder of the reach is supports a substantial fishery (Class III). The fishery in this reach is made up of channel catfish, carp, and black bullhead. Canada geese and mallards winter in this reach.

The 4,000-acre reservoir and surrounding seepage areas provide habitat for wintering Canada geese and mallards. From 1982 to 1987, an average of about 20,800 mallards and 7,100 Canada geese were present in January (NGPC, Lincoln, Nebraska, unpubl. data). The reservoir is also used by waterfowl during migration. Great blue herons use the reservoir and surrounding areas; a colony exists nearby. Bald eagles use the area during winter.

Walleye, white bass, yellow perch, and channel catfish are common in the reservoir. The coal-fired Gerald Gentleman Power Plant on the south shore of the reservoir obtains cooling water from the inlet canal and from the reservoir. Discharges from Lake McConaughy and South Platte Rivers determine canal inflows. Mallards and Canada geese winter on the reservoir.

Sutherland Canal: Keystone Diversion from Lake Ogallala to Sutherland Reservoir,

Canal flows are largely dependent on the amount of storage in Lake McConaughy. Seepage from Sutherland Canal, plus that from Sutherland Reservoir and the connecting canal to Maloney Reservoir has been beneficial in maintaining waterfowl wintering habitat in the South Platte River valley below Paxton, Nebraska.

The NGPC has rated this portion of the Sutherland Canal as a high priority (Class II) fishery resource. Rainbow trout, walleye, white bass, and yellow perch are the most regularly taken fish species. A portion of the fish population in the canal is derived from Lakes McConaughy and Ogallala. Sutherland Canal has medium to high value habitat for mallards and and for rainbow trout.

Flows in this reach have been reduced by upstream development for irrigation and municipal uses of water; more development is probable in the future. The upper 10 miles of the South Platte River valley in Nebraska support nesting mallards, blue-winged teal, and green-winged teal. Waterfowl winter in the upper half of this reach. From 1982 to 1987, an average of about 1,200 mallards and 500 Canada geese were present in January (NGPC, Lincoln, Nebraska, unpubl. data). In 1987, three least tern nests and one piping plover nest were found on the South Platte River about two miles west of Ogallala, Nebraska; no birds fledged from these nesting attempts.

This reach supports a limited (Class IV) fishery resource. Channel catfish and black bullheads are caught during some years. Habitats in this reach are of high value to wintering Canada geese and wintering and nesting mallards.

Upstream development has caused drastic changes in flow regimes; more development is probable. This reach includes the lower reach of the North Platte River. Portions of this reach support migrating and wintering waterfowl. The wintering waterfowl population is made up primarily of mallards and Canada geese. From 1982 to 1987, an average of about 950 mallards and 600 Canada geese were present in January (NGPC, Lincoln, Nebraska, unpubl. data). A state statutory waterfowl refuge is located on the river upstream of North Platte, Nebraska.

Between Sutherland and North Platte, the river and adjacent wetlands provide habitat for about 100,000 sandhill cranes each spring. The cranes spend up to six weeks in the area, roosting on the river and adjacent wetlands at night and foraging in wet meadows, grasslands, and croplands during the day. Wintering bald eagles occur throughout this reach. Use in recent years by piping plovers and least terns has not been recorded. Two whooping cranes have been confirmed on or near the river between Hershey and North Platte. The fishery resource in this reach was classified as high priority (Class II), providing habitat for channel catfish and rainbow trout. A variety of other fishes, such as walleye and white bass, are taken occasionally. The NGPC is investigating the feasibility of more intensive management for trout in this reach because of suitable water temperatures. Flow augmentation during the non-irrigation season would be a valuable management alternative.

Flows in this reach were reduced by upstream development; additional development is probable. Portions of this reach support migrating and wintering waterfowl. The wintering population consists primarily of mallards and Canada geese. From 1982 to 1987, an average of about 750 mallards and 500 Canada geese were present in January (NGPC, Lincoln, Nebraska, unpubl. data). Great blue herons are present throughout the reach with one active colony present in the area. Wintering bald eagles occur throughout this reach. Use by piping plovers and least terns has not been recorded in recent years.

This reach is a high priority (Class II) fishery resource providing habitat for channel catfish and rainbow trout. A variety of other fishes, such as walleye and white bass, are taken occasionally. The NGPC is investigating the feasibility of more intensive management for trout in this reach because of conducive stream water temperatures. Flow augmentation during the non-irrigation season would be a valuable management alternative. The northern redbelly dace, a state listed threatened species, has been collected in two small tributary streams near Sarben, Nebraska. Habitats in this reach are of high value to migrating and wintering mallards and to great blue herons.

Lake Ogallala was created by the removal of earth for construction of Kingsley Dam and the diversion structure which directs water into the Sutherland Canal. The lake occupies about 500 surface acres and inundates about 3 miles of North Platte River channel. Lake Ogallala currently serves as a reregulation facility for discharges from Lake McConaughy.

Lake Ogallala and the North Platte River downstream to Keystone provide winter habitat for several waterfowl species, primarily Canada geese and mallards. Other waterfowl species use Lake Ogallala during migration. Wintering bald eagles occur here in winter.

In the past, Lake Ogallala provided habitat for rainbow trout, yellow perch, white bass, channel catfish, and walleye. The state frequently stocked the lake with trout. Fishery conditions deteriorated after completion of the Kingsley hydropower unit in 1984. Because of low dissolved oxygen concentrations, many trout left the lake via the North Platte River and the Sutherland Canal. The installation of a bypass valve at Kingsley Hydro to aerate a portion of the releases when water temperatures exceed 18o C has apparently solved this water quality problem. Lake Ogallala has high value to migrating and wintering mallards and rainbow trout.

Lake McConaughy was created by Kingsley Dam on the North Platte River. The open water of the lake is used by migrating and wintering waterfowl. The Clear Creek State Wildlife Management Area supports wintering Canada geese and mallards. From 1982 to 1987, about 4,900 mallards and 3,100 Canada geese were present in January (NGPC, Lincoln, Nebraska, unpubl. data). Management of this area focuses on waterfowl.

Bald eagles winter around the reservoir, particularly at the upper end and near the dam. Two whooping crane sightings were confirmed near the Clear Creek marshes. Piping plovers nest along sandy exposed shorelines, but nesting success is poor. One pair of least terns successfully fledged young on the north shore of Lake McConaughy in 1989.

Lake McConaughy occupies about 30,000 surface acres when full. Lake levels are determined by inflows from the North Platte River and downstream releases for hydropower production and irrigation. More upstream development is proposed and may reduce the water supply of the North Platte River. Walleye, white bass, yellow perch, channel catfish, striped bass, smallmouth bass, and rainbow trout make up most of the sport fishery. Lake McConaughy is classified as a highest value (Class I) fishery resource. Lake McConaughy is a high value resource because of its use by mallards, wintering Canada geese, and rainbow trout.

The North Platte River and adjacent floodplain palustrine wetlands support migrating and wintering waterfowl. From 1982 to 1987, an average of about 17,100 mallards and 8,100 Canada geese were present in January (NGPC, Lincoln, Nebraska, unpubl data). Canada geese and mallards are predominant in the wintering populations.

About 10,000 to 12,000 sandhill cranes use this reach each spring downstream from Lewellen. The North Platte River from the upper end of Lake McConaughy to near Bridgeport was used historically by migrating whooping cranes. The latest confirmed sighting occurred near Bridgeport during July 16-23, 1950. Bald eagles are common winter residents and migrants in this reach.

This portion of the North Platte River has been designated a highest value (Class I) fishery resource. Channel catfish, carp, and forage fish maintain permanent populations. The river also supports rainbow trout, white bass, and walleye during yearly migrations. This river reach provides habitat for rainbow trout moving between Lake McConaughy and tributary spawning streams. This reach of the North Platte River has high value to wintering and nesting Canada geese, migrating and wintering mallards, and rainbow trout.

Tributaries to North Platte River Between the Wyoming Border and Bridgeport, Nebraska

Flows in these tributaries are largely dependent on seepage from the Inland Lakes and the associated canal system, as well as from irrigation return flows. Changes in historic water delivery regimes to the Inland Lakes and future irrigation water withdrawals could further deplete flows. Tributary streams, such as Red Willow and Nine Mile Creeks, have been designated as possessing high resource value by the USFWS because they support wintering mallards and are important as trout spawning habitat.

Palustrine Wetlands between the Interstate and Highline Canals and the North Platte River

Changes in historic water delivery regimes to the Inland Lakes and additional irrigation withdrawals could further reduce the water table causing more wetland loss. Palustrine wetlands in this reach support migrating and wintering waterfowl; some reproduction also occurs. University Lake supports a sport fish population. Palustrine wetlands in this reach provide high value habitat for mallards.

The Inland Lakes store irrigation water. Reductions of inflow from canals that lower lake levels in winter would degrade fish and wildlife habitat in the lakes and in downstream wetland and riverine habitat. The North Platte National Wildlife Refuge includes most of the water area of the Inland Lakes. The USFWS has little control over the water regimes, which largely depend on flows from facilities operated by the U.S. Bureau of Reclamation on the North Platte River in Wyoming. The refuge is managed primarily for migrating and wintering waterfowl and for bald eagles. From 1982 to 1987, an average of about 21,000 mallards and 2,400 Canada geese were present in January (NGPC, Lincoln, Nebraska, unpubl data).

The NGPC manages Lake Minatare and Winters Creek to provide a sport fishery. The Inland Lakes were designated as having high value to wintering and migrating mallards and Canada geese.

Following are descriptions of fish and wildlife resources associated with 18 habitat reaches in Wyoming. The geographic location and hydrologic features of these reaches are distinctive enough to separate the reaches into distinctive habitat areas. Each reach was assigned a code (except reservoirs) to aid in describing specific resources in the reach.

Riparian vegetation in this reach is well developed and dominated by eastern cottonwood. The sinuous channel in this reach has gravel riffles, long runs, and pools. Upstream water retention during the non-irrigation season nearly dewaters the river from the Guernsey Dam to the mouth of the Laramie River. Below the Laramie River, instream flow releases from the Grayrocks Dam maintain a flow of 22 cfs or greater in the North Platte River. The annual release of silt from the Guernsey Dam degrades riverine habitats. Whalen Diversion, about seven miles below Guernsey Dam, diverts water into the Interstate and Fort Laramie canals. About 247,000 acres of crops are irrigated from these releases.

The riparian areas and adjacent cropland support mule deer, white-tailed deer, ring-necked pheasant, wild turkey, eastern cottontail, and waterfowl. There are three great blue heron colonies in this reach. An increase in wood duck nesting has occurred in recent years; about 100 pairs currently now use this reach (Wyoming Game and Fish Department (WGFD), Cheyenne, Wyoming, unpubl. data) About 16,000 to 18,000 ducks and 30,000 to 40,000 Canada geese winter in this area (WGFD, Cheyenne, Wyoming, unpubl. data).

Bald eagles are common winter residents. Use of the North Platte River and the reservoirs by bald eagles was surveyed by the U.S. Bureau of Reclamation during 1978-1981. Peregrine falcons migrate through the area; an historic aerie is on the Goshen Rim east of Chugwater, Wyoming.

Estimated fishing pressure in this reach is about 5,800 angler-days annually. About 67% of the harvest and 55% of the angler effort occurs below the Guernsey Dam (WGFD, Fisheries Progress Report, 1975). Principal fish species sought are walleye, channel catfish, yellow perch, rainbow trout, and brown trout. The WGFD is considering development of a catfish fishery in this reach, if favorable non-irrigation season flows can be maintained. Improved winter flows may enhance bald eagle and waterfowl use of the reach. This reach has high value to wintering and nesting Canada geese, wintering bald eagles, mallards, nesting great blue herons, and to wood ducks.

Guernsey Reservoir is the fifth in a string of mesotrophic impoundments on the North Platte River in Wyoming. Water levels in the reservoir fluctuate dramatically from a summer irrigation pool of about 35,000 acre-feet to no storage by the end of September. The reservoir level is drawn down each July to flush out silt for use as a sealant in two downstream U.S. Bureau of Reclamation water supply canals.

Uplands adjacent to Guernsey Reservoir are vegetated primarily with ponderosa pine and Rocky Mountain juniper. The understory consists of bitterbrush and mountain mahogany. Little riparian vegetation developed adjacent to the reservoir. Upland habitats adjacent to the Guernsey Reservoir provide habitat for mule deer. A great blue heron and double-crested cormorant colony exists where the North Platte River enters the reservoir. Waterfowl use of the reservoir is limited by water level drawdown during the non- irrigation season. Bald eagles are common in early winter. Several nearby black-tailed prairie dog towns provide a potential habitat and a food source for black-footed ferrets. Peregrine falcons use the reservoir during migration.

Wide fluctuations in water levels prevent the establishment of a viable fishery. The Guernsey Reservoir is used heavily during the summer for water sports. A reservoir fishery could be maintained through provision of a minimum pool of about 11,000 acre-feet storage (USFWS, Cheyenne, Wyoming, pers comm.). A minimum pool level would also benefit wintering bald eagles and waterfowl. Presently, the WGFD does not actively manage the reservoir because of the water level fluctuations. Guernsey Reservoir has moderate value for wintering Canada geese and mallards, for nesting great blue herons and double-crested cormorants, and for American white pelicans during the summer.

This 20-mile reach includes steep canyons vegetated with Rocky Mountain juniper, ponderosa pine, and mountain shrub communities. The river crosses an alluvial floodplain characterized by cropland and stands of eastern cottonwood before entering Wendover Canyon above Guernsey Reservoir. Mule deer are the principal large mammal in this reach. Waterfowl use the river during migration and early winter. This reach supports five pairs of Canada geese and up to ten pairs of mallards per stream-mile during the nesting season (USFWS, Cheyenne, Wyoming, unpubl. data). Bald eagles are common during early winter. Black-tailed prairie dog towns in the area provide potential habitat and food for black-footed ferrets. Peregrine falcons use this river reach during migration.

The WGFD has determined that this reach supports a regionally important (Class 3) trout fishery. Estimated fishing pressure in this reach is about 7,000 angler-use-days occur annually (WGFD Unpubl. Prog. Rept. 1975). Rainbow trout are the primary species caught. Anglers also capture brown trout, channel catfish, walleye, and yellow perch. Other fish species present in this reach include common carp, longnose dace, river carpsucker, and several other cyprinids. The river fishery in this reach could be upgraded to a premium (Class I) fishery if higher non-irrigation season flows could be maintained. The USFWS (unpubl. data) estimates that this would require a minimum flow of 290 cfs. This flow number is subject to refinement by the WGFD. Continuous flow in this reach would also enhance the amount of riparian vegetation, such as eastern cottonwood and willows.

The riverine habitat in this reach has been designated as having moderate to high value for migrating and nesting mallards, nesting Canada geese, wintering bald eagles, and for rainbow trout and brown trout.

Water levels in the Glendo Reservoir fluctuate widely each year from 500,000 acre-feet in spring to about 64,000 acre feet in late September. Inflow to the reservoir is controlled by releases from upstream dams. Several tributaries in upstream reaches of the North Platte River contribute additional water and nutrients to the system. Most of the uplands adjacent to the reservoir are managed for public recreation by the Wyoming Recreation Commission. Stands of eastern cottonwoods and willows are found adjacent to the reservoir. Sage grassland, juniper woodland, and agricultural lands are the predominant upland habitats present.

Riparian and upland habitats surrounding the reservoir are subjected to constant noxious weed control programs which diminish their habitat value because beneficial plants are killed by chemical sprays. The exposed mudflats of the reservoir pool are vegetated primarily with annual grasses and forbs. The reservoir supports about 6,000 to 7,000 Canada geese and 10,000 to 15,000 mallards during the early winter (WGFD, Cheyenne, Wyoming, unpubl. data). American white pelicans use the reservoir as a foraging site during the summer. Three great blue heron nesting colonies are located along the upper North Platte River arm of the reservoir. Fall migrant shorebirds make extensive use of the Glendo Reservoir and bald eagles use the reservoir each winter. Uplands adjacent to the reservoir provide potential habitat for black-footed ferrets and nesting peregrine falcons.

The principal fish species in Glendo Reservoir are walleye, yellow perch, and channel catfish. Rainbow trout and brown trout are also present. The trout species are not presently released because of competition with walleye and other fish species. Unfavorable habitat conditions from fluctuations in reservoir levels also reduce the suitability of the waters for trout. Reservoir conditions are acceptable for walleye and yellow perch; both species are exploited by anglers. Other fish species include carp, white sucker, longnose sucker, river carpsucker, and northern creek chub. The reservoir fishery could be improved if a minimum pool of about 130,000 acre-feet was maintained (USFWS, Cheyenne, Wyoming, unpubl. data). The pool level figure is subject to refinement by the WGFD. This would also benefit wintering bald eagles and waterfowl in early winter.

The Glendo Reservoir has moderate to high value for mallards and Canada geese, the walleye fishery, nesting great blue herons, and summering American white pelicans. The reservoir also is used by bald eagles in winter.

Riparian vegetation is well developed in this 131 mile reach. High summer flows in combination with periodic flooding during high runoff years have maintained the riparian vegetation. Sagebrush grassland is the most common vegetative community adjacent to the river. The amount of irrigated cropland, including alfalfa, increases toward the downstream reach. The bulk of the diverted water is used to irrigate about 84,000 acres of cropland and to satisfy the municipal and industrial needs of Casper, Wyoming.

Pronghorn, mule deer, and white-tailed deer are the primary large mammals in this reach. White-tailed deer are restricted primarily to the riparian zone. The river and adjacent wetlands support migrant and nesting waterfowl. Nesting densities reach 10 duck pairs and 2 Canada geese pairs occur each river mile. Small concentrations of waterfowl occur in winter throughout this river reach. Four great blue heron colonies exist between Casper and Glendo Reservoir; a fifth exists near Bates Creek. Double-crested cormorant nesting colonies are located near Glenrock and on Soda Lake near Casper. American white pelicans use the 10-mile reach below Gray Reef Dam. Osprey nest near Casper and historically near Bessemer Bend above Casper. This reach supports one of the largest wintering concentrations of bald eagles in Wyoming. Eastern cottonwood trees along the river are important perch sites and are also used for nocturnal roosts. A bald eagle pair nested in 1988 and 1989 at Edness Kimball Wilkins State Park near Casper. As with other river reaches, there is a potential for black-footed ferrets. A peregrine falcon pair established a nesting territory near Douglas, Wyoming, in 1989.

This reach supports a high-quality trout fishery and receives heavy fishing pressure because of proximity to human population centers. A recent creel census revealed that the heaviest use is on the reach from Gray Reef Dam to the Dave Johnston Power Plant Dam. The 25-mile reach from Gray Reef Dam to Bessemer Bend was designated a premium (Class I) trout fishery. A 1973 creel survey revealed that about 8,000 angler-use-days occurred in this reach during March to November (WGFD, Cheyenne, Wyoming, unpubl data). Most fishing pressure occurred near Gray Reef Dam. Current estimates are about 15,000 to 20,000 angler use-days. Most fishing pressure at present is for bass. Important reasons for the designation were the popularity of the reach among anglers and the high standing crop of rainbow trout, brown trout, and cutthroat trout. The WGFD classified this river reach as a Class 3 trout fishery from Bessemer Bend to Dave Johnston Power Plant. Below the power plant, the North Platte River is primarily a warm-water fishery for channel catfish, black bullheads, and walleye. The lower 42 mile reach receives about 5,700 use-days annually.

Upstream flow releases maintain the fishery in this reach during the irrigation season. The federally-authorized minimum flow of 330 cfs for water quality maintenance is important for the fishery in the winter months. The cumulative effects of water development on riparian vegetation and associated fish and wildlife from alterations in the flow regime in this reach are of concern. A shortage of stream fishery opportunities exists in this portion of Wyoming (Fishery Division, WGFD, Cheyenne, Wyoming, pers. comm.). A minimum flow maintained at 570 cfs would improve the fishery in this reach (USFWS, Cheyenne, Wyoming, unpubl. data). This flow figure may be refined by the WGFD after completion of instream flow studies.

This reach has been designated as having high value for migrating and nesting mallards; nesting Canada geese; great blue herons, double-crested cormorants, osprey, and American white pelicans; and the trout fishery above Casper.

The Gray Reef Reservoir serves as a re-regulation reservoir for peak power releases from the Alcova Reservoir. A minimum flow of 330 cfs is released from the Gray Reef Reservoir to the North Platte River at all times for pollution abatement in the Casper area. Upland habitats adjacent to the reservoir are primarily sagebrush grassland. Mule deer are the principal large mammal in the area. American white pelicans, California gulls, Caspian terns, and waterfowl use the reservoir for foraging and nesting. Bald eagles use the reservoir in early winter. As with other reaches, there is potential habitat for black-footed ferrets and migrating peregrine falcons.

Fish are not released into the reservoir by the WGFD because of the fluctuating water levels. Rainbow trout and brown trout pass through the Alcova Reservoir outlet and provide some opportunities for recreation. Because of the small size, and because reservoir waters are used for re-regulation flows, there is little potential to improve habitats for fish and wildlife. The reservoir has been designated as having moderate value for American white pelicans and for migrating mallards.

Alcova Reservoir is a deep, relatively steep-walled waterbody with a limited littoral zone. Water levels remain fairly constant throughout most of the year. The principal factors influencing reservoir limnology are the reservoir operating system, natural flow variations in the primary upstream tributaries, and nutrient inflow. Vegetation of upland areas adjacent to Alcova Reservoir are characterized by Rocky Mountain juniper and big sage. Tablelands above the reservoir are sage grassland.

Important animals in the upland habitats include mule deer, pronghorn, sage grouse, and desert cottontail. Fremont Canyon provides nesting habitat for prairie falcon, red-tailed hawk, and golden eagle. Waterfowl use the reservoir during migration and in early winter. Waterfowl nesting is limited by the lack of natural nesting habitat and by human recreational activities. Caspian terns and American white pelicans use the reservoir as a foraging site.

Alcova Reservoir receives some use by bald eagles in winter. Potential peregrine falcon nest sites exist in Fremont Canyon. There is potential habitat for black-footed ferrets in the white-tailed prairie dog towns found in the adjacent uplands.

Alcova Reservoir supports an excellent rainbow trout fishery. The trout population in the reservoir is based on stocking large numbers of young trout annually. Zooplankton production remains high during the summer and provides a food source for rainbow trout. Alcova Reservoir is one of the most important reservoir fisheries in Wyoming because of the trout fishery and its proximity to a large population center. Walleye are also increasing in Alcova Reservoir and are an increasingly larger proportion of the fish species caught (WGFD, Cheyenne, Wyoming, unpubl. data). Future water management may have to include management and control of this species.

Because this reservoir provides a highly productive and heavily used fishery, any changes in present operating conditions must be closely examined. The present operating schedule is rigidly structured to provide releases to the Kendrick Irrigation Project during the summer. The Alcova Reservoir has high value for the rainbow trout fishery and moderate value for migrating mallards.

This reach flows through Fremont Canyon. Poor soil development and flow regulation contributed to a poorly-developed growth of eastern cottonwood and willows in the riparian zone. Stream flows are frequently shut off during the year and diverted through the Fremont Power Plant. No consumptive water use occurs in this reach. The number of large mammals is limited. Lands along and above the river provide habitat for mule deer. The steep-sided canyon walls provide potential nest sites for hawks, golden eagles, and peregrine falcons.

Riparian habitats in this reach receive some use by bald eagles in winter. Fremont Canyon has potential nesting habitat for peregrine falcons. Potential habitat for black-footed ferrets also exists because white-tailed prairie dogs are common in the area.

Water withdrawals limit use of this reach by fishes, although some species become trapped in deeper pools when flows are shut off. Some fishing is possible when water is released from Pathfinder Reservoir. This reach has moderate value to wildlife. The fishery in this reach could be improved to a premium (Class I) designation if a minimum stream flow was maintained (USFWS, Cheyenne, Wyoming, unpubl. data). The WGFD is developing instream flow recommendations for this reach.

The major source of inflow to the Pathfinder Reservoir is releases from the Seminoe Reservoir. The Sweetwater River also contributes significant runoff and nutrients to Pathfinder Reservoir. The reservoir contains about 1 million acre-feet of impounded water. Water levels commonly fluctuate more than 100 feet vertically during the irrigation season. Sagebrush grassland is the predominant habitat type in the uplands adjacent to Pathfinder Reservoir. The Pathfinder National Wildlife Refuge occupies a portion of the water surface and adjacent shoreline. The refuge is managed primarily for waterfowl.

Pronghorn and mule deer are the principal large mammals of the area. Bird Island supports a large colony of nesting American white pelicans, double-crested cormorants, Caspian terns, great blue herons, and California gulls. Terrestrial predators gain access to Bird Island when reservoir levels drop below 5,825 feet and pose a threat to ground-nesting birds during low run-off years when the reservoir level is drawn down below this level in the summer.

Pathfinder Reservoir is an important migration stopover area for ruddy ducks, redheads, and canvasbacks. About 400 pairs of ducks and up to 90 pairs of Canada geese use the reservoir during nesting (WGFD, Cheyenne, Wyoming, unpubl. data). Most nesting occurs in the Sweetwater River arm and the adjacent Soda Lakes of the Pathfinder National Wildlife Refuge.

White-tailed prairie dog towns exist in the adjacent uplands and provide potential habitat for black-footed ferrets. There have been three unconfirmed sightings of black-footed ferrets near Pathfinder Reservoir since 1983. A bald eagle winter roost is located adjacent to the reservoir in the Pedro Mountains. Pathfinder Reservoir is used by more wintering bald eagles than any other reservoir on the North Platte River. Peregrine falcons migrate through the area; potential nesting habitats exists nearby.

Water releases from Seminoe Reservoir provide an abundance of nutrients to Pathfinder Reservoir, which increases the production of fish biomass in Pathfinder Reservoir. Rainbow trout, brown trout, cutthroat trout, and walleye are the principal fish species taken by fishermen. The reservoir provides recreational opportunities popular with both resident and non-resident anglers. Improvements could be made in reservoir recreational opportunities with maintenance of a minimum pool level (USFWS, Cheyenne, Wyoming, unpubl. data). The WGFD is developing pool level recommendations for this reservoir. Nesting by colonial waterbirds could be enhanced if reservoir levels during the nesting season were maintained above the 5,825 foot level (USFWS, Cheyenne, Wyoming, unpubl. data).

Pathfinder Reservoir provides high value habitat for migrating waterfowl and nesting colonial waterbirds, and for the trout and walleye fishery. The reservoir also provides important winter habitat for bald eagles.

This reach is known as the Miracle Mile, and includes the 5-mile reach of the North Platte River between Kortes Dam and the headwaters of the Pathfinder Reservoir. No consumptive water use occurs in this reach. Upland vegetation is primarily sagebrush grassland. Riparian vegetation in this reach consists of eastern cottonwood and various willows. This is the only remaining riparian vegetation in a 60-mile reach of the North Platte River. Habitats in this reach are of regional importance because of the diversity of flora and fauna present, the limited extent of riparian vegetation in Wyoming, and the elimination of most riparian areas along the North Platte River due to construction of reservoirs.

Pronghorn and mule deer are the predominant large mammals in the area. The Seminoe Mountain herd of bighorn sheep uses the area during the winter. The upper reach of Pathfinder Reservoir and this reach are used by migrating waterfowl. Heavy recreational use of the area limits the extent of waterfowl nesting. American white pelicans use this reach for foraging.

Bald eagles use this reach extensively during the winter. Several nearby white-tailed prairie dog towns nearby provide potential habitat for black-footed ferrets. Peregrine falcons migrate through the area, but historically are not known to nest here.

This reach supports an important trout fishery. Seminoe Reservoir provides a nutrient subsidy for the river that contributes to rapid growth of food items for trout. The warmer waters released from Seminoe Reservoir encourage high productivity during winter months. Brown trout, cutthroat trout, rainbow trout, and walleye, move into this reach to feed and spawn. Annual stocking with rainbow trout supplements natural reproduction. This reach was classified by the WGFD as a premium (Class 1) trout fishery. In 1982, about 16,400 angler use-days occurred in this reach. The U.S. Congress established a minimum flow of 500 cfs in this reach to protect the stream fishery.

This reach has very high value for migrating waterfowl, the trout fishery, important winter habitat for large mammals, and as a feeding area for colonial nesting birds, including American white pelican, double-crested cormorant, Caspian tern, and great blue heron. The area is also important for wintering bald eagles.

Kortes Reservoir is a 4,750 acre-foot reregulation and power production reservoir below the tailwater of Seminoe Dam. The steepness and inaccessibility of the lands surrounding the reservoir limit use by large mammals, except bighorn sheep. The canyon and adjacent Seminoe Mountains are the core area for a local bighorn sheep herd. The canyon provides nesting sites for prairie falcon and golden eagle. Waterfowl use of the reservoir is limited. Biological productivity of the reservoir is low because of short retention times. The principal fish species present include rainbow trout, brown trout, and walleye.

Management opportunities are limited at this reservoir because of its size and re-regulation function. Kortes Reservoir is used in winter by bald eagles. The adjacent canyon walls provide potential nest sites for peregrine falcons. The reservoir has moderate value for wildlife.

Seminoe Reservoir receives its inflow from the North Platte and Medicine Bow rivers. Total storage varies around 1 million acre-feet. The Seminoe Reservoir is surrounded by several habitat types, including montane, sagebrush grassland, and riparian communities. Operation of the Seminoe Reservoir requires that the lowest storage levels be in spring so runoff from the North Platte and Medicine Bow river drainages can be captured. Water is stored in the Seminoe Reservoir during the summer. Flows are released to the Pathfinder Reservoir primarily during the non-irrigation season. This operation schedule provides flexibility in the system, more power generation, and a recreation pool during the summer. The reservoir level occasionally fluctuates by up to 100 feet in elevation. A recommended minimum pool level for Seminoe Reservoir is being developed by WGFD.

Uplands adjacent to the reservoir provide habitat for pronghorn and mule deer. About 180 bighorn sheep live in the Seminoe Mountains on the west side of the reservoir. The diversity of habitats here supports many bird species. Sage grouse is common throughout the sage grasslands. Golden eagles and ferruginous hawks also nest in the uplands. The reservoir provides nesting habitat for Canada geese and mallards. Ruddy ducks, canvasback and redhead use the reservoir during migration.

Seminoe Reservoir receives substantial nutrient inflow from the North Platte and Medicine Bow river drainages. Under some conditions algal blooms reduces zooplankton numbers and limits the food supply for the reservoir fishery. The WGFD manages the reservoir under its basic yield concept. The bulk of the rainbow and brown trout in the reservoir are released annually by the WGFD. Walleye were first recorded in the system about 1961. Predation by walleyes has required the WGFD to increase the size limit of rainbow trout stocked in the system to enhance their likelihood of survival. The reservoir receives about 58,000 angler use-days annually.

Bald eagles use the reservoir during early winter and peregrine falcons migrate through the area. Black Canyon near the dam and near Dugway contains potential peregrine falcon nesting habitat. Nearby white-tailed prairie dog towns provide potential habitat for black-footed ferrets. Evidence of past use of adjacent uplands by black-footed ferrets was obtained during a 1979 search (Martin and Schroeder 1979). Populations of persistent watercress, a plant species considered for possible endangered species listing, are known to occur at various locations around the reservoir and along the lower Medicine Bow River.

Seminoe Reservoir has moderate to high value for migrating diving ducks, nesting and migrating mallards, the trout and walleye fishery, and large mammal habitat. The reservoir also is important for the persistent watercress and to bald eagles.

The North Platte River enters Wyoming through Northgate Canyon and continues north through Saratoga valley before entering Seminoe Reservoir. Water diversions are used to irrigate about 85,000 acres of cropland in the Saratoga valley. The range of habitats in this reach supports many wildlife species. Mountain areas along the upper North Platte River provide summer range for elk, mule deer, and bighorn sheep. The lower foothills and the prairies provide winter range for large mammals. The Saratoga valley downstream to the Seminoe Reservoir provides nesting habitat for Canada geese and mallards; up to 1,000 ducks use the area in early winter (WGFD, Cheyenne, Wyoming, unpubl. data). Great blue herons are present throughout the reach; six colonies are located in the valley and one near Fort Steele. Several double-crested cormorant nesting colonies are located near Bennett Peak.

The North Platte River above Sage Creek is a premium (Class 1) trout fishery. Trout also inhabit the tributary streams that enter the North Platte River above Saratoga valley. Tributaries provide spawning and rearing habitat for trout. Sediment inflow reduces stream quality in the 58-mile reach from Sage Creek to Seminoe Reservoir. Reduced stream quality has contributed to a lowered stream classification (Class 2) for this river reach. The principal fish species captured in this reach include cutthroat trout, brown trout, rainbow trout, and walleye.

The bald eagle nesting population increased to six active territories and five active nests in 1988. This reach is also important to wintering bald eagles. Peregrine falcons migrate through the area. The numerous white-tailed prairie dog towns provide potential habitat for black-footed ferrets.

This reach has high value for mallards, nesting Canada geese, nesting great blue herons and double-crested cormorant, the trout fishery, and winter range for large mammals. Saratoga valley is also important for nesting and wintering bald eagles.

The Laramie River originates in the Medicine Bow Range of Wyoming and the Rawah Mountains of Colorado. The river enters Wyoming near Woods Landing, flows through a mountainous valley, and continues northward across the Laramie Plain before entering the North Platte River near Fort Laramie. Major water depletions in the Laramie River basin include irrigation for about 160,000 acres of cropland and cooling water for the Wheatland Power Plant. The Laramie River Basin provides habitat for elk, pronghorn, mule deer, and white-tailed deer. Bighorn sheep reside in the Laramie Mountains near Wheatland, Wyoming, and in the Medicine Bow Mountains. Ring-necked pheasant habitat is found in the farmlands near Wheatland. Wild turkeys occur in the Laramie Mountains.

Wetlands of the Laramie Plains from Woods Landing downstream to Wheatland #3 Reservoir have the largest number of nesting ducks in the Wyoming portion of the Central Flyway. Regionally important wetlands are in the Hutton Lake and Bamforth National Wildlife refuges and along the Laramie and Little Laramie rivers. Riverine habitat on the Laramie Plain supports up to 30 pairs of ducks and 0.5 pairs of Canada geese per river mile. Below the Wheatland #3 Reservoir, the river flows are much reduced resulting in lower populations of nesting waterfowl. The Grayrocks, Wheatland #1, and Festo reservoirs provide nesting habitat for waterfowl. About 8,000 Canada geese use the Wheatland #2 Reservoir each fall. Grayrocks Reservoir supports 15,000 to 20,000 common mergansers, 5,000 to 10,000 common goldeneye, and up to 40,000 other ducks until early December (WGFD, Cheyenne, Wyoming, unpubl. data).

Wetlands on the Laramie Plains are used for nesting by several colonial waterbirds. About 285 pairs of American white pelicans and double-crested cormorants use Bamforth and Cooper lakes. Western grebe, Clark's grebe, snowy egret, black-crowned night-heron, white-faced ibis, Forster's tern, and black tern nest on several lakes in the region. Five great blue heron colonies are in the southern portion of the Laramie Plain, and another nesting colony is near Wheatland.

The upper 10 miles of the Laramie River in Wyoming support a Class 2 trout fishery. Streamflows are reduced below Woods Landing during the irrigation season and produce a lower quality stream fishery throughout this river reach. Flows are diverted for irrigation near Wheatland, creating a low quality fishery. Irrigation return flows and inflow from the North Laramie River enhance stream flows in the Laramie River from the confluence of these two rivers to the Grayrocks Reservoir. Brown trout occur downstream from Grayrocks Reservoir. Portions of several streams draining into the Laramie River low value trout waters, including the Little Laramie and North Laramie rivers, and the Sybille, Bluegrass and Duck creeks. Lakes on the Laramie Plain are popular trout fishing areas. The Wheatland #3 Reservoir provides excellent fishing opportunities for walleye and trout.

Bald eagles winter throughout the Laramie Basin. Many bald eagles are commonly found along the Grayrocks Reservoir, especially during gizzard shad die-offs. Black-tailed and white-tailed prairie dog towns are in the basin and provide potential habitat for black-footed ferrets. Peregrine falcons migrate through the area; a historic aerie is on the Little Laramie River. Wyoming toads were found 16 to 18 miles west of Laramie, Wyoming, in 1987. Eight egg masses were found and 47 males heard calling here in 1988. The only known population of this species consists of about 80 to 100 individuals. The Laramie River provides habitat for mallards and Canada geese, colonial nesting waterbirds, and wintering bighorn sheep.

The Sweetwater River originates along the south flank of the Wind River Mountains and flows east prior to entering the Pathfinder Reservoir. Water depletions are primarily for irrigation of hay meadows. The drainage area provides important habitat for pronghorn, mule deer, elk, and moose. Irrigated river valleys are vegetated with several species of willow that create habitat for moose which have expanded in numbers in recent years. Sage grouse occur throughout the sage grassland. Irrigated meadows provide brood habitat for sage grouse. The Sweetwater River valley provides nesting habitat for several waterfowl species. Mean nesting densities are about 15 pairs per river mile (WGFD, Cheyenne, Wyoming, unpubl. data). The Sweetwater River valley is also used by migrating waterfowl.

Sweetwater River is a low value fishery through most of its length. Rainbow trout and brook trout are the principal species in the upper reaches; brown trout are dominant downstream from the Sweetwater Canyon.

The lower Sweetwater River valley is used by bald eagles in winter. Peregrine falcons migrate through the area. The Sweetwater Canyon contains potential nesting habitat for peregrine falcons. White-tailed prairie dog towns provide potential habitat for black-footed ferrets. The Sweetwater River has very high value to nesting and migrating mallards, nesting Canada geese, the trout fishery, and important winter habitat for large mammals.

The Medicine Bow River originates in the Medicine Bow Mountains and flows east to Seminoe Reservoir. Irrigation of about 44,175 acres of hay meadows is the principal consumptive use in the Medicine Bow basin. The mountain area provides summer range for elk and mule deer, as well as waterfowl nesting habitat. Sagebrush grassland provides habitat for pronghorn, mule deer, and sage grouse. Bighorn sheep occur in the mountainous areas.

The upper reaches of the river above Elk Mountain, Wyoming, support populations of brook trout and rainbow trout. The 30-mile reach below Medicine Bow, Wyoming, is turbid for much of the year and is low quality trout habitat.

Bald eagles use the area in winter. Peregrine falcons migrate through the area and are provided with potential nesting habitat in the mountains. White-tailed prairie dog towns provide potential habitat for black-footed ferrets. The Medicine Bow River provides moderate to high value habitat for nesting raptors, nesting mallards, the stream fishery, and wintering large mammals.

Several tributary streams originate in the Laramie Mountains and flow to the North Platte River. Tributary streams include Deer, Box Elder, La Prele, La Bonte, Chugwater, and Horse creeks. Flow depletions for irrigation of cropland are the primary consumptive uses of the water in these tributary streams. The Laramie Mountains are a popular recreation area for residents of Casper, Douglas, and Wheatland, Wyoming. The mountains and forests provide habitat for mule deer, elk, and bighorn sheep. Pronghorn habitat exists in lowland areas that have not been fenced or sprayed for sagebrush. Area streams and reservoirs provide habitat for nesting and migrating waterfowl. Most streams contain brook trout and rainbow trout in their upper reaches and brown trout in the lower reaches.

The middle and lower reaches of most streams are used by wintering bald eagles. A bald eagle nocturnal roost is located on Box Elder Creek. Canyons associated with these streams provide potential peregrine falcon nesting habitat. Adjacent black-tailed and white-tailed prairie dog towns provide potential habitat for black-footed ferrets. The tributary streams have moderate to high value for fish and wildlife resources.

The South Platte River drainage in Wyoming contains Lodgepole, Crow, Lone Tree, and Dale creeks. These are small tributaries that originate in the Laramie Mountains west of Cheyenne and flow east through the prairie region before leaving Wyoming in Laramie County. Irrigation is the primary consumptive water use. The mountain areas provide habitat for mule deer and elk; pronghorn are found on the prairie.

The upper mountainous reaches of these streams contain numerous beaver ponds that provide habitat for brook trout. Flows are much reduced in many of the prairie reaches of these streams, lowering their ability to support a fishery. Three small reservoirs (Granite, Chrystal and North Crow reservoirs) on upper Crow Creek are used heavily for recreational purposes by residents of Cheyenne.

Habitats throughout the area are used by wintering bald eagles. Black-tailed prairie dog towns provide potential habitat for black-footed ferrets. The Colorado butterfly plant, a federal Category 2 candidate species, is found along the riparian zones of Crow and Lodgepole creeks from near Cheyenne downstream to Nebraska. South Platte River tributary streams have been identified as having moderate value for fish and wildlife resources.

Following are descriptions of fish and wildlife resources associated with 29 habitat reaches in Colorado. Each reach is geographicaly distinct and supports different habitat characteristics. The reaches (except reservoirs) are assigned a code for identification.

The North Platte River originates in the Park Range of the Routt National Forest and flows southeast before turning to the north near Walden, Colorado. Major tributaries include the Michigan River, Illinois River, Grizzly Creek, Roaring Fork Creek, and the Canadian River. The North Fork and its tributaries drain North Park, a large high mountain valley with elevations above 8,000 feet. North Park is a productive agricultural area with livestock grazing as the primary economic use. Logging and mining are also important industries.

The North Platte River through North Park is a narrow, meandering stream. Substrate is rubble, cobble, gravel, sand, and silt. Several small lakes and irrigation reservoirs are on the North Platte River in North Park. There are no major diversions on the North Platte River in Colorado although landowner diversion structures are common. Potential future consequences for North Platte River fish and wildlife resources are from water diversions to the front range, increases in summer and second-home construction, and water storage. No major water developments are currently planned.

Bald eagles migrate through the valley and will probably use the area as long as adequate roost sites and open water exist. Potential peregrine falcon aeries occur in the mountains surrounding the valley. The North Park phacelia, an endangered plant, occurs near Walden. This plant is found on outcrops of the Coalmont Formation associated with eroded bluffs along streams. Black-tailed prairie dog towns may provide potential habitat for black-footed ferrets.

The North Platte River supports many wetlands, including the Arapaho National Wildlife Refuge. The refuge and other wetland areas provide habitat for many migratory bird species. Waterfowl breeding populations since 1968 have averaged 16,292 pairs (Szymczak 1986). Mallards are the most numerous breeding species. The wetland and riparian habitats available in the valley allowed for the successful introduction of moose by the Colorado Division of Wildlife (CDW). Wetland types in North Park include willow carrs and fens near treeline, and wet meadows and willows along streams at lower elevations.

Historically the North Platte River drainage had no native salmonids (Hayden 1871), but stocking efforts have now introduced brown and rainbow trout into the system. The North Platte River from the Wyoming border to the confluence of Roaring Fork Creek and Raspberry Creek is a major fishing stream (Class I) . Although the 5.3-mile reach of the North Platte River, from the Routt National Forest boundary downstream to the Wyoming state line, is a designated trout water, the density and biomass of the fishes over 6.5 inches were lower than in other streams (Nehring 1983). Streambank erosion may be depressing natural reproduction in the North Platte River (Nehring 1986).

The southwestern corner of the North Park area provides nesting habitat for greater sandhill cranes. The area supported six nesting pairs in 1978 (Torres et al. 1978). North Park was formerly occupied by river otter and lynx, both listed by the state as endangered species. Elk, moose, mule deer, and pronghorn are the primary large mammals present. North Park provides habitat for sage grouse. Significant changes in land use in North Park are not anticipated in the near future. A reliable water supply and the present lack of new development allow stable habitat conditions in North Park.

The Laramie River originates at Chambers Lake in the Rawah Mountains of north central Colorado, and flows north into Wyoming. The Laramie River is as a Class 1 Coldwater fishing stream with a large self-sustaining population of brown trout of relatively high biomass. Nongame fishes appear to be limited in numbers and species. Public access is limited to two miles of the reach, the remaining reach is in private ownership. Ranching is the primary land use in the drainage. Several small reservoirs in the drainage provide varying levels of salmonid sport fishing.

This reach flows through a 9,000-foot elevation mountain valley known as South Park. This area is a former inland lake that developed into wet meadow or high elevation desert. South Park is in the wheatgrass-needlegrass shrub steppe zone (Kuechler 1964). Agriculture is the primary economic use of South Park (i.e., cattle grazing, hay production), although much of the water formerly used for irrigation is now transported to the Denver Metropolitan Area for municipal use. Peat mining operations are also ongoing in the valley.

The South Platte River originates in the mountains bordering South Park on the northwest. Major tributaries include the Middle Fork of the South Platte River, Four-mile Creek, and Trout Creek. Tarryall Creek drains the northern portion of the valley, joining the South Platte River outside of South Park below Eleven-mile Reservoir.

The South Platte River and tributaries in South Park are primarily meandering single-thread streams. Riparian vegetation is predominantly willow and wet meadow plant community types. Agricultural diversion structures are common and two large and several smaller reservoirs have been constructed for front range municipal users. Channelization and other forms of stream alterations are localized and to date appear to have had minimal influence. However, extensive destruction from large scale placer mines has occurred to the Middle Fork of the South Platte River near Fairplay. Physical impacts to wetland habitat have been severe and are related to peat mining wetland drainage, and historical agricultural practices.

Federally listed species that occur in South Park include wintering bald eagles, peregrine falcons, and whooping cranes. Most bald eagles are found at Eleven-mile and Antero reservoirs. A historic peregrine falcon aerie is in the southeastern portion of the valley and potential aeries may exist in surrounding mountain areas. Efforts to reintroduce peregrine falcons to this region are on-going. Whooping cranes from the experimental Gray's Lake flock have been sighted at Antero Reservoir.

South Park has extensive wetlands, but with fewer open water areas than North Park. Wet meadows are the predominant wetland type. Riparian willow communities have largely been eliminated to enhance hay production. Data on waterfowl production for South Park are limited. South Park does not support the same density of breeding ducks as North Park (Szymczak 1986). Waterfowl production occurs in irrigated hay meadows and along river floodplains (Szymczak 1986). Removal of willows from stream courses has reduced the wildlife value of the riparian zone. Elk, bighorn sheep, black bear, pronghorn, and mule deer are the principal large mammals in South Park.

Water supply is relatively reliable, but fluctuates widely in seasonal availability. Instream flows in spring tend to increase as use is shifted from agriculture. Future negative influences on fish and wildlife resources may include: intensive water development (lined channels, additional storage, etc.) and increased peat mining, recreational and residential development.

This reach includes 28 miles from the Antero Reservoir to the Spinney Mountain Reservoir. The Middle Fork of the South Plate River joins the South Fork near the midpoint of this reach and contributes over 10% of the base flow downstream from this point. This reach is a meandering channel through montane meadows; riparian vegetation is limited to grasses and sparse willow clumps along grazed streambanks. The fish assemblage includes rainbow trout, brown trout, and white suckers. Grazing, erosion, sedimentation, and low mean annual temperatures may affect the fishery potential by reducing habitat quality.

The South Platte River between Spinney Mountain Dam and the upper end of the Elevenmile Reservoir is an excellent fishery for brown and rainbow trout. This reach is managed as a catch and release fishery by the CDW. Flows in this reach are subject to fluctuation because of the proximity of the two water supply reservoirs.

The South Platte River and its South Park tributaries support a trout fishery. The Middle Fork of the South Platte River in the Tomahawk State Wildlife Area and Tarryall Creek from its confluence with the South Platte to the Pike National Forest boundary are designated Wild Trout Water by the CDW. Other streams in the area provide fishing for rainbow trout, brook trout, cutthroat trout, and brown trout.

The river is confined in the upper end of this reach to the Eleven-mile Canyon and is characterized by plunge pool/shallow gravel riffle habitat. Tarryall Creek discharges into the South Platte River in this reach and flows are regulated by releases from the Elevenmile and Tarryall reservoirs. The fish assemblage consists of rainbow trout, brown trout, and several species of suckers. Northern pike escape occasionally from the Eleven-mile Reservoir and inhabit this reach. The reach between Beaver Creek and Cheesman Reservoir is classified as a Wild Trout Water by CDW. Cheesman Reservoir has in recent years been used heavily by wintering bald eagles.

This reach extends from the Cheesman Reservoir downstream to the confluence with the North Fork of the South Platte River. The river below the Cheesman Reservoir is confined to the Cheesman Canyon and flows are influenced by reservoir releases. The riffle-pool complex and catch-and-release fishing regulations have increased the standing crop of trout. Longnose and western white suckers occur in the canyon area in low densities. The trout standing crop, aesthetic appeal, and proximity to Denver of this reach contribute to a heavily used stream fishery.

The standing crop estimate in 1985 in the upper Cheesman Canyon section was 533 lbs/ac (CDW, Denver, Colorado, unpubl. data). With the exception of the Fryingpan River below Ruedi Reservoir, the standing crop of coldwater salmonids in the South Platte River from Cheesman Dam to Scraggy View is greater than any other major stream in Colorado.

The river from the lower boundary of the Wigwam Club downstream to the confluence with the North Fork has a lower gradient than that upstream of Cheesman Reservoir and is characterized by broad gravel riffles and large deep runs and pools. Limited boulder habitat is also present. The fish community is made up of rainbow trout, brown trout, brook trout, and longnose and western white suckers. Some longnose dace may be present also.

This reach extends from the confluence of the North Fork of the South Platte River to Chatfield Reservoir. The North Fork contributes more than 10% of the base flow. A reproducing brown and rainbow trout population exists from Strontia Springs Reservoir downstream to the Marston Diversion. Downstream from the Marston Diversion, the fishery is enhanced by stocking rainbow trout. Yellow perch, longnose suckers, and longnose dace have been observed occasionally. The fish assemblage in the lower reaches of this section of the river is transitional between the cold water species in Waterton Canyon and the cool and warm water species in Chatfield Reservoir. Other species not previously collected during sampling probably move from the reservoir into the river and are present at certain times of the year. Habitat in the reach downstream from the Marston Diversion has been modified by the installation of stream habitat structures which improved pool-to-riffle ratios. Although only non-motorized access exists throughout this reach, Waterton Canyon is a popular recreation area.

Wetlands and riparian areas within this reach include three communities: willow/forb, cottonwood/willow, and wet meadows. These plant associations primarily occur along the mainstem and North Fork of the South Platte River and their tributaries. The vegetative diversity and productivity in association with the availability of water make these habitats particularly attractive for several wildlife species.

Elk, mule deer, and bighorn sheep are the principal large mammals in this area; black bear and mountain lion also occur. Bighorn sheep are of management concern to the CDW because of their low numbers, deteriorating habitat, and status as one of the few remaining herds at low elevations in Colorado. The Waterton Canyon herd is the focus. This herd declined from 48 individuals to 16 between 1978 and 1987.

This reach extends from the stilling basin of the Chatfield Dam downstream to Bowles Avenue in Littleton. The slope decreases considerably in this reach, and the river is more sinuous. However, a large portion of this reach has been channelized by the Corps. Riverine habitat is characterized by wide, shallow gravel riffles and long runs; there are few instream habitat structures. The fish assemblage consists of low densities of rainbow trout, brown trout, and other cool and warm water species. The Corps has constructed in-stream structures to enhance fish habitat in this reach.

This reach flows through the Littleton Floodplain Park and most of its length has public access. Proximity to the urban area and the diverse fish assemblage contribute to public fishing use. The CDW developed specific management plans for the river and adjoining gravel pit lakes, which provide a highly used recreational fishing complex. The Corps has created additional riparian/wetland habitat in the park.

The North Fork of the South Platte River originates near the continental divide west of Grant, Colorado, and flows south and east before joining the South Platte River about 20 miles southwest of Denver. The North Fork from Grant to the South Platte River is a major fishing stream (Class I) . Drainage from inactive mines in the upper watershed is believed to be partially responsible for reduced aquatic productivity above Grant.

The North Fork from the Roberts Tunnel to Buffalo Creek has a moderate slope and flows through a combination of montane meadow and canyon habitat. The stream is channelized and has a low-flow thalweg from below the confluence with the Roberts Tunnel to downstream of Bailey. Slope decreases below the Roberts Tunnel. Brown trout are most numerous in the North Fork and are seemingly self-sustaining. Lower densities of rainbow trout and brook trout are also present. Widening of U.S. Highway 285 from Webster to Bailey may constrict the river in places and reduce habitat quality.

From Buffalo Creek to the confluence with the South Platte River, slope increases and the channel straightens in this reach, which flows through narrow foothill canyon habitat. Brown trout are numerous and some brook trout, rainbow trout, and longnose suckers are present.

Sixty-six identified tributaries to the South Platte River were sampled as part of the impact analysis for the Two Forks Environmental Impact Statement conducted by USFWS (USFWS, Denver, Colorado, unpubl. data). Brook trout and rainbow trout were predominant in most streams and lesser numbers of brown trout were present in some streams. Other species collected included longnose sucker, white sucker, fathead minnow, and longnose dace. Fish were not present in some streams. The upper portions of most streams were fairly steep and their slopes moderated as they entered the South Platte River floodplain; fish presence did not necessarily correspond to gradient. Fish assemblages and biomass were generally related to stream morphology, flow regime and available habitat types. Larger streams generally support better trout habitat and higher fish biomass.

These streams have mixed public accessibility. The upper portions of the streams are typically on National Forest or other public lands and have unrestricted public access. The lower portions of the streams are primarily on private lands with restricted public access. These streams are important as spawning and rearing areas for the mainstem rivers.

Antero Reservoir: Antero Reservoir was constructed in 1909 as part of the Denver Water Department's South Platte River collection system for the Denver metropolitan area. The reservoir is at an elevation of 8,963 feet, covers about 4,102 surface acres, and is about 16 feet deep. The reservoir is stocked annually with rainbow trout. A self-sustaining brown trout and brook trout fishery exists in the reservoir which is stocked with kokanee salmon and cutthroat trout. White suckers and longnose suckers are probably the only native fishes now present. The suckers were 73% of the fish samples in 1984 (CDW, Denver, Colorado, unpubl. data).

Spinney Mountain Reservoir: The Spinney Mountain Reservoir was constructed in 1981 by the City of Aurora for domestic water supply. The reservoir is near Hartsel and occupies 2,498 surface acres. The maximum reservoir depth is 46 feet. Cutthroat trout have been stocked in the reservoir since 1982. Other fish in the reservoir are brown trout, rainbow trout, brook trout, kokanee salmon, northern pike, longnose suckers, and white suckers. Fish growth in the reservoir is excellent. In 1984, trout and northern pike were about 58 percent of the captured fish; 42 percent of the fish taken were longnose suckers and white suckers.

Eleven-mile Reservoir: Eleven-mile Reservoir is located upstream from Lake George, Colorado. The reservoir was built in 1932 as part of the Denver Water Department's water supply collection system and covers 3,365 surface acres. The water level annually fluctuates from 0 to 50 feet, averaging 6 feet. Fish stocking since 1973 has consisted primarily of rainbow trout and kokanee salmon. Other fish stocked since 1973 include cutthroat trout, lake trout, northern pike, and walleye. Walleye are the only introduced fish which have not become established in the reservoir. The fishery has been managed primarily on a put-and-take basis for rainbow trout.

Cheesman Reservoir: Cheesman Reservoir was first filled in 1905 as part of the Denver Water Department's collection system. Located at an elevation of 7,382 feet, the reservoir occupies an area of 874 acres. The maximum depth is 190 feet and the annual fluctuation of the reservoir presently ranges from 0 to 190 feet, averaging 41 feet. Lake whitefish, cutthroat trout, walleye, brown trout, and kokanee salmon have been periodically stocked. Sampling results show that yellow perch and white suckers are the most abundant species. Cheesman Reservoir in recent years has been used heavily by wintering bald eagles.

Strontia Springs Reservoir. This reservoir was completed in 1982 by the Denver Water Department to supply water to the Foothills Water Treatment Plant. No fish sampling has been conducted since the completion of this reservoir, but the CDW has stocked it with rainbow trout since 1983. Brown trout, longnose suckers, and white suckers are also present. Because of the short retention time, reservoir fluctuations, and apparent low productivity, the Strontia Springs Reservoir probably does not support a large standing crop of fishes.

Chatfield Reservoir: The Chatfield Reservoir is on the southwest edge of the Denver metropolitan area. The reservoir was constructed on the South Platte by the Corps for flood control. Most of the fish with which the Chatfield Reservoir has been stocked since 1974 are rainbow trout. Other released salmonids include brown trout and cutthroat trout. Releases of largemouth bass and channel catfish are used in ongoing research by the CDW. Plum Creek is a secondary tributary to the Chatfield Reservoir.

Cherry Creek Reservoir: Cherry Creek Reservoir (900 acres) is a Corps of Engineers flood control reservoir constructed on Cherry Creek, a tributary of the South Platte River which drains a large area to the south of Denver. Cherry Creek is an extremely popular recreation area for metropolitan residents. This reservoir provides fishing for a variety of warm and cool water species. Valuable wetland habitat has developed at the reservoir's upper end. Phosphorous loading in the reservoir has become a water quality concern.

This reach includes the Denver metropolitan area. The South Platte River through this reach is primarily a single thread with few secondary or overflow channels. Dominant substrate ranges from cobble to gravel below Chatfield Dam to sand at the reaches lower end. Channelization and other forms of structural controls have severely altered the character of the river. There are several ongoing attempts to improve the recreational and visual values of the metropolitan river corridor. Funding and other constraints limit their effectiveness, however. Winter waterfowl use of this reach is high because of warm water inflow from industry, sewer outflows, and powerplants. Aggregate mining in this reach is a major activity and may be partially responsible for streambed degradation.

Bald eagles use the South Platte River in the northern Denver area in winter. About 30 wintering bald eagles roost at the Rocky Mountain Arsenal (USFWS, Golden, Colorado, unpubl data). Some of these birds forage along the South Platte River and other rivers and reservoirs with open water. Additional use of this reach by bald eagles includes birds that roost at sites other than the arsenal. Black-tailed prairie dog towns, in upland areas in and near the Denver metropolitan area, may provide potential habitat for black-footed ferrets. Whooping cranes are rare migrants through the area.

Riparian and wetland habitats in this reach were altered by urban development. Flood and erosion control along the South Platte River displaced much of the cottonwood/willow riparian zone. Sand and gravel operations have also been a major influence through streambed degradation and alteration of the riparian zone. Draining and filling for urban development are the major causes of loss or damage to wetland habitats.

Although habitats in this reach have been reduced in extent and are often isolated pockets within developed areas, they support a remarkable diversity of wildlife. Canada geese and other waterfowl, raccoon, muskrat and songbirds can commonly be found in this reach. The fish community is similar to that described in the Chatfield Dam to Littleton section. Instream habitat has been severely degraded or eliminated in many locations.

The South Platte River in this reach is characterized by a meandering main channel with numerous secondary channels. Changes in the natural hydrograph have reduced flood flows and allowed riparian vegetation and agricultural practices to encroach on the historic flood plain. No on-stream reservoirs are presently located in this reach of the South Platte River; however the Bureau of Reclamation's proposed Narrows Unit would be located near the mid-point of this reach. Agricultural and municipal diversions are common throughout this reach. The substrate is dominated by sand and silt along the entire reach.

Federally listed species in this area include wintering bald eagles. The Colorado greenback cutthroat trout, a federally listed threatened species, is in several high elevation tributaries. Whooping cranes are occasionally seen on area reservoirs. The presence of black-tailed prairie dog colonies near the river provide potential habitat for black-footed ferrets. Peregrine falcon aeries are in several locations along the front range of the mountains near tributary drainages of the South Platte River.

The riparian zone in this reach is an important segment of the remaining cottonwood-dominated riparian habitat in Colorado and provides habitat for many wildlife species. About 90 percent of the wildlife species in Colorado use riparian habitats at some stage of their life cycle. Lack of natural regeneration of cottonwoods in Colorado is of increasing concern because many existing forests are mature and are not being replaced (Knopf, et al. 1988).

Wetlands in this reach are usually associated with abandoned meanders, reservoirs and ponds, irrigation systems, and sand and gravel pits. Waterfowl use these areas during migration and the nesting season. Waterfowl harvest along the front range and the South Platte River is high. Several state wildlife areas adjacent to the South Platte River receive heavy use by waterfowl hunters. Numerous private hunting clubs exist for waterfowl hunting. Wetlands in this reach support a variety of nongame birds, including the white faced ibis, which is a candidate for federal listing as threatened or endangered. Wintering bald eagles and other raptors prey on migrating or wintering waterfowl. Aquatic habitat in this reach is varied. The upper elevations of tributaries to the South Platte River support cold water salmonid fisheries and grade toward warm water species as they approach the South Platte River. The trout fisheries, which exist in portions of the Cache la Poudre River and North St. Vrain Creek, are designated Wild Trout Water by the CDW. The South Platte River supports a limited sport fishery. Most of the fishing opportunities in northeastern Colorado are in lacustrine habitat (reservoirs, oxbows, sand and gravel pits).

Fish species managed by the CDW include largemouth bass, walleye, yellow perch, bluegill, channel catfish, and "wipers" (Morone chrysops x M. saxatilis). Open water areas provide habitat for waterfowl and shorebirds. Most of the habitat for diving ducks, American white pelicans, grebes, and other open water birds is limited to these areas. Reservoirs in this reach include Julesburg, Sterling, Prewitt, Jackson, Riverside, Barr Lake, and Horsetooth. Barr Lake supports a nesting pair of bald eagles and nesting waterfowl. Raptors breed or winter along the South Platte River and its tributaries. American white pelicans occupy reservoirs adjacent to the river system. Mule deer and white-tailed deer are the principal large mammals. Wild turkeys are being introduced to this reach of the South Platte River. The johnny darter and plains orangethroat darter are species of state concern in this reach.

Plum Creek is a perennial stream draining the western portion of the Palmer Divide. The drainage supports a variety of wetlands, small reservoirs and stock ponds, and riparian habitat. Nongame fishes are in suitable habitat throughout the drainage. Small numbers of shorebirds and waterfowl breed and forage here. The lower reaches of Plum Creek support a large and diverse wetland and riparian system. Plum Creek drains into the Chatfield Reservoir.

The Cherry Creek headwaters are in the Black Forest region south of the Denver metropolitan area. This stream does not support a sport fishery. Nongame fishes are present in suitable habitat. Wetland and riparian habitat of the Cherry Creek drainage are valuable for migratory birds, waterfowl, and furbearers. Cherry Creek is a single thread stream; its substrate ranges from bedrock-boulder in upper reaches to sand in the lower reaches.

The headwaters of this stream are along the continental divide west of Georgetown, Colorado. Water quality degradation problems from mine drainage have been identified in portions of the watershed. Sport fishing for salmonids occurs in upper reaches of the drainage. The riparian corridor along Clear Creek was altered by construction of Interstate 70 through the mountains and by channelization and gravel mining in the Denver metropolitan area. Several small storage reservoirs and hydroelectric facilities were constructed in the Clear Creek basin. Clear Creek has a bedrock and boulder channel for most of its course through the mountains. On entering the plains, Clear Creek remains a single thread channel. Its substrate grades from cobble to gravel to sand as gradient decreases. Ute ladies tress orchid occurs in two small populations along Clear Creek as it leaves the mountains.

St. Vrain Creek originates in the mountains south of the Rocky Mountain National Park. The portion of the drainage basin in the southeastern corner of the Rocky Mountain National Park supports several populations of green-back cutthroat trout, federally listed as threatened. Boulder Creek is a major tributary of the St. Vrain and drains the southern portion of this system. As the stream enters the plains, a valuable cottonwood dominated riparian community develops. Wintering bald eagles use this corridor for roosting and feeding. A communal roost for about 30 bald eagles is near the confluence of the St. Vrain and Boulder creeks. The St. Vrain system is affected by municipal and agricultural water diversions, particularly along the lower reaches. Small populations of Ute ladies tress orchids are along Boulder Creek.

The headwaters of the Big Thompson River are in the Rocky Mountain National Park near Milner Pass. The Little Thompson River is a major tributary in the system. Colorado greenback cutthroat trout are in several tributaries of the Big Thompson River in the park. Non-native salmonids occur throughout the drainage below the park. Water diversion structures are common outside of the park. As with all South Platte tributaries, the Big Thompson supports an important riparian zone, which is occupied by wintering bald eagles and migratory birds.

The Cache la Poudre River is the major drainage for the northern portion of the front range of the Rocky Mountains. Headwaters of the Cache la Poudre River are in the Rocky Mountain National Park. The North Fork of the Cache la Poudre River, a major tributary, has its headwaters near the Wyoming border. Both streams have high quality trout fisheries in the upper reaches. A reach of the upper Cache la Poudre River is a National Wild and Scenic River. The Northern Colorado Water Conservancy District proposed a large main stem dam and reservoir at Grey Rock just below the confluence with the North Fork. This dam is part of a larger project that includes a pumped storage hydro-electric project and an off stream irrigation storage reservoir. As the river leaves the mountains, diversions for irrigation and municipal use greatly reduce instream flows. During low flow and heavy irrigation, discharge below the Fort Collins sewage treatment plant can be reduced to zero. A limited warm water fishery of native and introduced species exists below Fort Collins. A cottonwood-dominated riparian corridor exists in this reach.

South Platte River tributaries that drain the short grass prairie to the east and south of the South Platte River are primarily intermittent. Major drainages include Bijou, Boxelder, Kiowa, and Beaver creeks. Reaches of these streams near the headwaters may have perennial flows. Surface flows in the lower portions of the drainage occur only during precipitation, however. These streams are an important source of sediment to the South Platte River system during periods of high flow. Woody riparian vegetation of these streams is scattered intermittently along the channel, probably in response to local changes in water table elevations. Crow Creek is the major tributary to the north, draining the Pawnee National Grasslands.

Barr Lake (1,900 acres) is an off-channel irrigation reservoir northeast of Denver near Brighton. The reservoir is owned by a private irrigation company, however, the surrounding land is administered as Barr Lake State Park by the Colorado Division of Parks and Recreation. Barr Lake supports a pair of nesting bald eagles and a great blue heron colony. Migrating and nesting waterfowl make extensive use of the lake. Sport fishing for warm water species is popular at Barr Lake and the area is heavily used by bird watchers. The CDW maintains a nature center within the park. Many nongame migratory birds, including shorebirds, stop over or breed near Barr Lake. The Colorado Bird Observatory bird banding station is operated at Barr Lake. Palustrine wetlands are near the upper end of the lake and below the dam.

The Riverside Reservoir is a private off-channel irrigation reservoir, 20 miles east of Greeley, near the South Platte River. The reservoir provides resting and feeding habitat for migrating waterfowl and shorebirds. Migrating bald eagles forage at the reservoir. The only known nesting colony of American white pelicans in Colorado exists on the Reservoir. Also present are nesting colonies of double-crested cormorants, California gulls, and several heron species.

The Empire Reservoir south of the South Platte River is a privately-owned off-channel irrigation reservoir. The reservoir is about 25 miles east of Greeley. Like Riverside Reservoir, the Empire Reservoir has no public access. Wildlife values include habitat for waterfowl, shorebirds, and other migratory birds. This reservoir also receives use by migrating bald eagles.

Jackson Reservoir (2,960 acres) is located north of the South Platte River about 33 miles east of Greeley. Jackson Reservoir is a privately owned irrigation reservoir. Jackson Reservoir supports a warm water sport fishery including largemouth bass, yellow perch, walleye, bluegill, catfish and "wipers". Migratory birds use the area for resting, foraging, and nesting. Wintering bald eagles also feed on waterfowl and fish while the reservoir remains unfrozen.

Prewitt Reservoir (2,430 acres), a privately-owned off-channel irrigation reservoir with public access, is about 11 miles southwest of Sterling, south of the South Platte River. Prewitt Reservoir provides a warm water sport fishery for bass, catfish, and walleye. Prewitt Reservoir is used by waterfowl, shorebirds, and nongame passerines. Wintering bald eagles forage along the reservoir while it remains ice free.

Sterling Reservoir (2,880 acres) is a private off-channel reservoir with public access. Sterling Reservoir is located about 10 miles northwest of Sterling, Colorado, north of the South Platte River. Resource values at Sterling Reservoir include a warm water sport fishery, migratory bird nesting and migration habitat, and wintering bald eagle roosting and foraging. Water level fluctuations from irrigation withdrawls may reduce habitat values seasonally.

Julesburg Reservoir (1,580 acres) is an off-channel irrigation reservoir about 17 miles west of Julesburg, Colorado. Fish and wildlife resources associated with Julesburg Reservoir include a warm water sport fishery and migratory bird nesting and migration habitat. Bald eagles may use the reservoir before it freezes.

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Platte River Ecosystem Resources and Management, with Emphasis on the Big Bend Reach in Nebraska

Appendices

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