Playa wetlands are wind-formed, nearly circular depressions located in semi-arid areas. They have a clay layer in the soil under the wetland that keeps runoff water from seeping into the ground. This clay layer was formed by water movement over thousands of years. Most playas are not directly connected to groundwater. Playa wetlands are located throughout the northwest three-fourths of the state, except in the Sandhills. The major playa complexes in Nebraska include the Rainwater Basins, Central Table Playas, Southwest Playas, and the Todd Valley.
Rainwater Basin Profile
The Rainwater Basin complex occupies a 4,200 square mile area in 17 south-central Nebraska counties. It was named for the abundant natural wetlands that formed where clay-bottomed depressions catch and hold rain and runoff water. The landscape of the complex is characterized by flat to gently rolling plains formed by deep deposits of loess (wind blown) silt-loam soil. The wetlands were formed by wind action and tend to have a northeast to southwest orientation. There frequently is a hill located immediately south or southeast of the wetland where the windblown loess was deposited. Surface water drainage in the region is poorly developed resulting in numerous closed watersheds draining into these wetlands. Most of the wetlands in this region do not receive groundwater inflow. Wetlands range in size from less than one to over one thousand acres.
Loss and Threats
Original soil survey maps from the early 1900s indicate that approximately 4,000 major wetlands totaling nearly 100,000 acres were present at the time of settlement. Schildman et al. (1984) estimated that less than 10 percent
(374) of the original major wetlands and 22 percent (20,942) of the original wetland acres identified on early soil surveys remained in 1982. This trend study did not attempt to estimate the quantity and quality of smaller wetlands that were not identified on early soil surveys. However, because small wetlands are more vulnerable to destruction, it is likely that the proportion of loss documented by Shildman for larger wetlands is even greater for the smaller wetlands. Using National Wetland Inventory (NWI) digital data and recent soil survey maps, a multi-agency wetland team in 1990 identified 34,103 acres of Rainwater Basin wetlands remaining (Raines et al. 1990), and of these only 28,260 acres were naturally occurring palustrine basins (Smith and Higgins 1990). These studies indicated that palustrine (marsh-like) emergent wetlands were decreasing, and virtually all remaining wetlands have been degraded in some fashion. Rainwater Basin wetlands were identified by the U.S. Fish and Wildlife Service as one of nine areas in the U.S. of critical concern for wetland losses (Tiner 1984).
Rainwater Basin wetlands were given the highest ranking, a priority 1, in the Nebraska Wetlands Priority Plan (Gersib 1991). The remaining wetland resources of the Rainwater Basin complex continue to face numerous threats, mostly related to conversion to cropland. Rainwater Basin wetlands face the direct threat of elimination by drainage and/or filling. The construction of concentration pits (also called dugouts or reuse pits) is common and threatens the functions of wetlands by converting shallow productive water spread over a large area into a smaller, deep and less productive water pit. Water pollution, especially sediment, can seriously reduce the functions of Rainwater Basin wetlands. Additionally, nearly all Rainwater Basin wetlands are threatened by changes to their watershed that divert water away from wetlands or concentrate upland runoff water into concentration pits. Of greatest concern is the cumulative impact of all of these threats that cause shallow wetlands to lose a few inches of water and become dry uplands. The spread of an aggressive cultivar of reed canary grass (Phalaris arundinacea) is a major threat. Reed canary grass forms dense, uniform stands in wetlands and provides minimal habitat for water birds. The spread of purple loosestrife (Lythrum salicaria) is an additional threat. Purple loosestrife is an introduced plant of little value to wildlife that out-competes desirable native plants. No information is available on the extent of purple loosestrife abundance or distribution throughout the Rainwater Basin complex; however it has been observed in a few basin wetlands and along the Platte River.
Functions and Values
Rainwater Basin wetlands are most noted for their importance to waterfowl, especially during the spring migration (Gersib et al. 1992, Gersib et al. 1989(a), U.S. Fish and Wildlife Service and Canadian Wildlife Service 1986). They host seven to fourteen million spring-migrating ducks and geese annually, providing the nutrient reserves necessary for migration and reproduction further to the north (M. Vrtiska, Nebraska Game and Parks, pers. comm.). Approximately 90% of the mid-continent population of greater white-fronted geese, 50% of the mid-continent population of lesser snow geese, 50% of the mid-continent population of mallards and 30% of the continent population of northern pintails use the Basins during spring migration. In some years the Basins also produce substantial numbers of ducks (Evans and Wolfe 1967). Over 257 species of birds have been recorded in the Rainwater Basin and 131 species may breed there (Mollhoff, 2001). Recent surveys have identified that a minimum of 200,000-300,000 shorebirds representing 34 different species migrate through the Basins during the spring (Adrian Farmer, USGS, Pers. Comm). Thirty-four species of waterbirds including herons, egrets, rails, terns and gulls have been observed in the Rainwater Basin. Rainwater Basin wetlands are regularly used by the federally endangered whooping crane, the threatened bald eagle and the threatened piping plover. Rainwater Basin wetlands provide water quality functions in the form of flood storage, nutrient retention, and sediment trapping (Gersib et al. 1989(b)). Because of the impermeable clay pan characteristic of Rainwater Basins and water table elevations that lie more than 50 feet below the wetlands, groundwater discharge does not normally occur. One exception occurs in Phelps County where Platte River irrigation water has resulted in groundwater discharges into some basins (Gersib et al. 1989(b)). Groundwater recharge is limited to periods of high precipitation when surface water in wetlands extends beyond the clay layer associated with wetland soils and seeps through more permeable upland soils (Keech and Dreeszen 1959). Nearly all Rainwater Basin wetlands provide for recreation activities, particularly hunting and fur harvesting. The public is showing increased interest in using Rainwater Basin wetlands for other recreation such as bird watching and nature photography. Select Public Use Areas (this is not a complete listing of public areas but instead is a list of representative areas that are geographically dispersed and accessible) http://mountain-prairie.fws.gov/rainwater/. http://mapserver.ngpc.state.ne.us/website/gpc_land/viewer.htm. C Cottonwood Waterfowl Production Area (WPA), 2 mi. W., 1 mi. N. of Bertrand, Phelps Co. C Sacramento Wildlife Management Area (WMA), 2 mi. W. of Wilcox, Phelps Co.
• Lake Seldom, ½ miles south of Holdrege, Phelps Co. C Funk WPA, 1 mi. N. of Funk, Phelps Co. C Gleason WPA, 4 mi. S., 4 mi. W. of Minden, Kearney Co. C Jensen WPA, 6 mi. N. of Campbell, Kearney Co. C Harvard WPA, 3 mi. W. of Harvard, Clay Co. C Springer WPA, 2 mi. S., 7 mi. W. of Aurora, Hamilton Co. C Kissinger WMA, 1 mi. N. of Fairfield, Clay Co. C Massie WPA, 3 mi. S. of Clay Center, Clay Co. C Pintail WMA, 5 mi. S., 2 mi. E. of Aurora, Hamilton Co.
C Hultine WPA, 6 mi. E. of Harvard, Clay Co. C Eckhardt WPA, 4 mi. N., 3 mi. W. of Ong, Clay Co. C Mallard Haven WPA, 2 mi. N of Shickley, Fillmore Co. C Rauscher 1 mi. S., 4 mi. E. of Sutton, Fillmore, Co. C Kirkpatrick Basin North WMA, 4 mi. W., 2 mi. S. of York, York Co. C Sinninger WPA, 2 mi. S., 3 mi. E. of McCool Junction, York Co. C Father Hupp WMA, 2 mi. W. of Bruning, Thayer Co. C North Lake Basin WMA, 1 mi. N. of Utica, Seward Co.
Conservation Programs and Contacts
Rainwater Basin Joint Venture — The Rainwater Basin Joint Venture was established in 1991 as a component of the North American Waterfowl Management Plan. It involves numerous partner agencies, organizations and individuals. Its objectives are to: 1) protect, restore, and create an additional 25,000 wetland acres, plus 25,000 acres of adjacent uplands; 2) provide reliable water sources for a minimum of 1/3 of all protected wetland acres to assure sufficient water quantity, quality, and distribution to meet migratory waterfowl and waterbird needs; and 3) develop and implement wetland enhancement strategies to optimize those values wetlands provide to waterfowl, endangered species, and other waterbirds. Participation in acquisition and private lands projects is strictly voluntary. Contact the Rainwater Basin Joint Venture Coordinator, 2550 N. Diers Ave., Suite L, Grand Island, NE 68803, (308) 382-8112. http://www.rwbjv.org/. Other contacts include the Nebraska Game and Parks Commission District Office in Kearney (308) 865-5310 and the U.S. Fish and Wildlife Service office in Kearney (308) 236-5015.
Central Table Playas Profile
Central Table Playa wetlands are situated on relatively flat, loess soil tablelands surrounded by a landscape that is highly dissected by drainages. The largest cluster of wetlands is located near the town of Arnold in Custer County, but similar wetlands are scattered in some of the surrounding counties. A particularly large wetland basin located 11 miles east of Arnold has been the source of much speculation that its formation was caused by meteorite impact. However, recent investigations suggest it is of wind-formed origin, similar to other playa wetlands (Flowerday 2001). Central Table Playas receive water from runoff and are small (mostly less than 5 acres), temporarily and seasonally-flooded wetlands. The complex may represent an extension of the Southwest Playas east toward the Rainwater Basin and Todd Valley complexes. The wetlands in this complex are possibly remnants of a larger complex of wetlands that was naturally eroded, breached and drained by streams. It’s unknown why this area has a more developed natural drainage pattern than the other complexes.
Loss and Threats
Losses and threats to the wetlands in this complex are less well known than for many other complexes in the state. Casual observation indicates that the loss of these wetlands falls somewhere between the loss levels of the Southwest Playas and the Rainwater Basin. Some of the wetlands have been modified by concentration pits or drained by drainage ditches. In some locations, the hydrology of the watershed has been altered by the placement of terraces and diversions that reduces the amount of water entering the wetlands. Most of the Central Table Playas are farmed as conditions allow.
Functions and Values
Our understanding of the functions and values of the Central Table Playa wetlands is limited by the lack of information. The wetlands are often visited by endangered whooping cranes during migration. These wetlands also provide habitat for migrating waterbirds, including waterfowl, shorebirds, and wading birds. Select Public Use Areas- None Conservation Programs and Contacts
Contact the Nebraska Game and Parks Commission District Office in North Platte (308) 535-8025.
Southwest Playas Profile
The playa wetlands of southwest Nebraska occupy small clay-lined depressions on nearly flat tablelands of loess soil. These freshwater wetlands receive water from runoff and are small (mostly less than 5 acres), temporarily and seasonally-flooded wetlands. Most have no natural outlet for water. In most years these wetlands dry early enough in the growing season to be farmed. Southwest Playa wetlands are similar to Rainwater Basin wetlands farther east, except that the Rainwater Basin complex receives greater rainfall, and the wetlands there tend to be larger.
Loss and Threats
Due to the small amount of rainfall received (16-18 inches per year) in the Southwest Playa region, there has been less drainage of these wetlands than has occurred in many other complexes. Some of the wetlands are drained into concentration pits or road ditches, but most simply dry up naturally and are farmed. Wheat is the dominant crop in the area, but corn and even soybean acreage has been increasing. In some locations, the hydrology of the watershed has been altered by the placement of terraces that reduce the amount of water entering the wetlands. These terraces also reduce the amount of eroded soil entering the wetlands. Since eroded soil filling the wetlands is an added threat to the Playas, soil erosion treatments are needed in the watershed of these wetlands. However, care needs to be taken to ensure that the erosion treatments do not reduce the wetland’s water source.
Functions and Values
Our understanding of the functions and values of the Southwest Playa wetlands is limited. Casual observations indicate that these wetlands provide important habitat for migrating waterfowl and shorebirds, and cover for pheasants. These water areas are especially important to wildlife in the dry High Plains region of the United States where wetlands are often scarce. Select Public Use Areas- None Conservation Programs and Contacts
The Playa Lakes Joint Venture is a multi-state partnership for wetland and bird conservation that covers portions of western Nebraska. Contact the Playa Lakes Joint Venture Coordinator, 103 East Simpson Street, LaFayette, CO 80026, (303) 926-0777. http://www.pljv.org/index.html. Contact the Nebraska Game and Parks Commission District Office in North Platte (308) 535-8025.
Todd Valley Profile
The complex is split into 2 regions. The region south of the Platte River is located in an ancient valley of the Platte River (termed the Todd Valley) that runs northwest to southeast through part of Saunders County (Lueninghoener 1947). The valley has partially filled with sand deposits and fine, wind-blown loess soils after the River moved to its present location. The region north of the Platte River is located on an ancient floodplain terrace between the Platte River and Shell Creek and along Logan Creek. Todd Valley wetlands occupy small, clay-lined, closed depressions located in loess soils. They are mostly fresh-water, seasonally and temporarily-flooded wetlands that receive most of their water from runoff.
Loss and Threats
Losses within this wetland complex have not been quantified. However, examination of soil maps and wetland maps, combined with limited site visits, suggest that many Todd Valley wetlands have been altered or eliminated. These losses have been caused by concentration pits, drainage and road ditches, tile lines, and in some areas by agricultural drainage wells that drain water into the underlying sand layers. The principal threat facing Todd Valley wetlands is continued conversion to agricultural production.
Functions and Values
Todd Valley wetlands provide functions similar to those of Rainwater Basin wetlands. Since the individual wetlands tend to be smaller than Rainwater Basin wetlands, and the total complex is smaller in geographic extent, they don’t attract concentrations of migratory waterbirds as large as the Rainwater Basin wetlands. Little is known about the hydrologic functions of the Todd Valley wetlands. Select Public Use Areas-http://mapserver.ngpc.state.ne.us/website/gpc_land/viewer.htm. Wilkinson WMA, 2 miles south of Platte Center.
Conservation Programs and Contacts
Todd Valley Wetland Foundation, P.O. Box 759, Columbus, NE 69602-0749. Other contacts include the Nebraska Game and Parks Commission District Office in Lincoln (402) 471-5561 or Norfolk (402) 370-3374.