Walnut Creek
Watershed
Master Plan
The Walnut Creek Management Authority (WMA) was created in 2014 as a response to concerns about high bacteria, nitrate, turbidity, flash flooding and stream bank erosion. The WMA received a $123,500 grant from the Iowa Department of Natural Resources to develop the watershed plan in late 2014.
The Walnut Creek Management Authority (WMA) was created in 2014 as a response to concerns about high bacteria, nitrate, turbidity, flash flooding and stream bank erosion. The WMA received a $123,500 grant from the Iowa Department of Natural Resources to develop the watershed plan in late 2014. The Walnut Creek Watershed is one of the most quickly urbanizing watersheds in Iowa, encompassing nearly 53,000 acres in Dallas and Polk County.
RDG's effort to develop the Walnut Creek Watershed Management Plan addresses EPA's nine elements for watershed planning and focuses on smart-growth principles. It reviews the character of the watershed; identifies key pollutants and their sources; details policies, practices and priorities to employ in urban and rural settings; outlines an outreach and connectivity plan; defines a monitoring plan to determine if implemented efforts are meeting desired goals; and plans for future amendments to the plan based on lessons learned through implementation of the plan.
Land owners, farmers, suppliers, planners, designers and policy-makers need to understand the types of “tools” there are in the “toolbox” to address the water quality issues identified in this plan. Many people may not be familiar with these practices.
This chapter is not intended to be a detailed design guide for such practices. It is intended as a resource to help people understand what each practice is, what it is intended to do, where they are most likely to be located and where to go for additional information.
To help this plan provide meaningful information for recommendations to the whole of the watershed, planners focused their attention on three sub-watersheds, representing the primary conditions found in Walnut Creek.
By focusing scientific study on these three subwatershed types, the planners have gained the most information from stream assessment fieldwork and computer modeling. The recommendations for these three subwatersheds serve as a “template” of sorts for the balance of the watershed under similar conditions.
Three "Case Study" Sub-watersheds:
• A developing area in parts of Waukee, Clive and Urbandale along Little Walnut Creek is expected to see rapid urban growth over the next ten years
• An agricultural area draining to Walnut Creek in rural Dallas County
• A primarily developed urban area within parts of Waukee, Clive and West Des Moines that drains to South Walnut Creek (which flows through Country Club Lake)