The Walnut Creek Lake and Recreation Area, near Papillion, Nebraska, represents a new approach to reservoir development. Walnut Creek Lake planners, aware that Omaha area lakes suffer from excess sediment and nutrients, set out to prevent those problems from the start. The project partners were the Papio-Missouri River Natural Resources District, the City of Papillion, Sarpy County, University of Nebraska Cooperative Extension, the U.S. Department of Agriculture's Natural Resources Conservation Service, Game and Parks Commission, and Department of Environmental Quality (DEQ).
An initial accomplishment was the creation of a 15-member Clean Lakes Community Council consisting of area farmers, residents, and other private citizens. The Council's mission was to develop management goals for the lake watershed that would serve the needs and desires of the community and protect the lake from polluted runoff. The Council quickly established itself as the driving force for the project.
Innovative approaches to protecting watershed
The Walnut Creek watershed was entirely agricultural and enjoyed an unusually high level of land treatment at the beginning of the project. The Council and project partners recognized, however, that creation of a lake would quickly attract residential and commercial development in the watershed and with it the excessive erosion characteristic of land development. To guard against this threat, the Council drafted a special ordinance for the lake watershed that requires a high level of erosion control on construction sites and provides for higher penalties than usual for violators of the ordinance. The City of Papillion subsequently adopted the ordinance within its jurisdiction of the lake's watershed. The practices required by the ordinance provide the first barrier to keep sediment on the development site and out of the lake.
Further protections were built into the design of the lake itself. The DEQ's Nonpoint Source Pollution Management Program provided funding through section 319 for outreach and installation of best management practices to reduce sediment and nutrient runoff into the lake. Islands and jetties dissipate wave action and prevent shoreline erosion, and sediment retention basins intercept sediment before it reaches the lake. Shoreline plantings stabilize soils, break up wave action, and provide food and habitat for aquatic organisms. Pallet stacks, tire reefs, and brush piles placed in the bottom of the lake provide shelter for fish. Restrictions prevent boaters from generating destructive wakes that erode shorelines and disturb aquatic wildlife. The cost of installing these practices as preventive measures is a fraction of the cost of installing restorative measures after a lake has suffered degradation.
To protect against the high levels of erosion caused by commercial development around Walnut Creek Lake, strict erosion control standards were implemented around the lake.
Water quality improvements
The goal of the project partners and the Community Council was to create a model lake designed to resist the pollutant pressures typical in eastern Nebraska and to meet or exceed its design lifetime. Early water quality data suggest that goal will be achieved. The initial water transparency of 61 inches is expected to stabilize in the long term to about 28 inches, well above the average of 22 inches for other area lakes. In-lake total phosphorus concentrations should stabilize at 0.07 milligram per liter (mg/L) from the current 0.05 mg/L; other area lakes average 0.08 mg/L total phosphorus. Sediment basins and other erosion controls will limit lake volume loss to 0.27 percent per year compared to the average 0.85 percent loss in other area lakes.
High water quality and habitat enhancements are expected to make Walnut Creek Lake the premier fishery among the Omaha area lakes. An added bonus of the project is that it leaves behind an energized group of watershed residents. The Clean Lakes Community Council is dedicated to ensuring that protective measures remain in place to protect the lake from polluted runoff.
DEQ has adopted a community-based approach to watershed planning for all nonpoint source priority watersheds, based on the experience with the Walnut Creek project. Formation of a Citizen Watershed Council to advise the agency's Technical Advisory Committee is a key feature of the process. A manual is being developed to guide the project sponsor, Watershed Council, and Technical Advisory Committee through the planning process. The process is being initiated or implemented in two watersheds where new reservoirs are being constructed and in six watersheds where reservoir renovations are planned or under way.