Nebraska's Wetland Family

Wetlands aren't always wet and they certainly aren't all alike.

Like members of a family, they have traits and tendencies linking one to another, but each has its own distinct personality to help define it.

Just as there isn't always agreement on what a wetland is, experts also don't always agree on what defines Nebraska's wetland types, or how many different types there are.

One such listing comes from the Nebraska Game and Parks Commission's recently published "Guide To Nebraska's Wetlands and their conservation needs." The guide is available at no charge through the Nebraska Game and Parks Commission, P.O. Box 30370, Lincoln, NE 68503-0370.

The guide divides Nebraska wetlands into four major categories and 14 subcategories.

Playa Wetlands

These wetlands are wind-formed, nearly circular depressions in semi-arid areas. They are primarily located in the northwest three-quarters of the state, except for the Sandhills.

Rainwater Basin wetlands encompass 4,200 square miles in 17 south-central counties. They are named in part for their abundant natural marshes.

Central Table Playas occur on relatively flat, loess soil tablelands surrounded by a landscape highly dissected by drainage. The largest cluster is near Arnold, but similar wetlands are scattered in some surrounding counties.

Southwest Playas are the playa wetlands of southwest Nebraska. These are primarily small (less than five acres), seasonal and temporarily flooded wetlands. They are often very similar to the Rainwater Basin wetlands that are further east.

Todd Valley wetlands are two regional complexes. One is south of the Platte (in an ancient valley of the Platte, called the Todd Valley). The other is north of the Platte in another ancient floodplain between the Platte and Shell Creek and along Logan Creek. These wetlands also tend to be seasonal and temporarily flooded.

Sandhill Wetlands

These wetlands are formed in depressions in sandhills areas where the groundwater intercepts the land's surface. The area is the largest contiguous tract of grassland remaining in the U.S. and also the largest stabilized sand dune area in the Western Hemisphere.

The Sandhills encompass more than 19,000 square miles and overlie several groundwater aquifers of the Ogallala Formation. More than a million acres of lakes, marshes and wet meadowns are present in the Sandhills. Fens are a rare type of wetland found in this region. In the western part of the sandhills are numerous alkaline wetlands that attract shorebirds, because of their insects and other invertebrates.

Loup/Platte River Sandhills wetlands are in a narrow band of wind-deposited sand from the confluence of the Platte and Loup Rivers (at Columbus) to near Ravenna. There are numerous, small, freshwater wetlands in this region.

Saline/Alkaline Wetlands

As their names suggest, these wetlands are characterized by their saline or alkaline water they get from groundwater or from concentration by evaporation.

Eastern Saline wetlands led to the establishment of the City of Lincoln because of the short-lived mining industry they produced in the area in the 1860's. These wetlands occur primarily in swales and depressions in the floodplains of Salt Creek and its tributaries. They get their salinity from groundwater passing through an underground rock formation that contains salts deposited by an ancient sea that once covered the state.

Western Alkaline wetlands are primarily on the floodplain of the North Platte River, upstream from Lewellen and along the upper reaches of Pumpkin Creek. Their alkalinity comes from the salts of sodium carbonate and calcium carbonate becoming concentrated in the soil from high rates of evaporation in this semi-arid region.

Riverine Wetlands

These wetlands are very closely associated with the floodplains of all the states rivers and streams. Riparian zones are part of them. They encompass wetlands, "Ox bows" (abnadoned stream channels), sandbars, tree falls, side channels and wooded areas.

Central Platte River wetlands are also known as the "Big Bend Reach" and extend about 90 miles, from Lexington to Chapman. Many of these wetlands are known as wet meadows, which attract migrating Sandhill Cranes and endangered Whooping Cranes each spring.

Lower North Platte River wetlands are in the lower reach of the North Platte, from approximately Sutherland to North Platte. The complex includes riverine and marsh-like wetlands, many of which are temporary and seasonally flooded.

Lower Platte River is that part of the Platte from where the Loup River joins it, near Columbus, to the Platte-Missouri confluence, south of Omaha. This area of the river has fewer acres of wetlands and wet meadows than the Central Platte.

Missouri River floodplain harbors riverine and marsh-like wetlands following the stateline from eastern Boyd County to the southeastern corner of the state in Richardson County. Upstream from Ponca the river has remained largely unchannelized and there are numerous islands and wetlands in that area.

Elkhorn River wetlands often occur in oxbows, or former channels of the river. They range from permanent lakes to temporarily flooded meadow areas.

Niobrara River wetlands include a variety of types in the river's floodplain. They get water from the river and from numerous springs located along the river valley's canyon walls.

Source: "Guide to Nebraska's Wetlands and their conservation needs, by Ted LaGrange, 1997.