WALNUT CREEK WATERSHED

Walnut Creek and its tributaries traverse 97 miles and drain 52,643 acres in Dallas and Polk Counties. Sixty percent of the watershed is rural/agriculture and forty percent is urban. This figure is changing rapidly.

The watershed includes the communities of Clive, Dallas Center, Des Moines, Grimes, Urbandale, Waukee, West Des Moines, and Windsor Heights.

Walnut Creek Watershed is one of the most critical watersheds in Iowa. The Des Moines Water Works intake valve is located one mile downstream from where Walnut Creek empties into the Raccoon River. Consequently, this watershed is a source of drinking water for 350,000 residents in Polk and Dallas Counties.

Current water quality problems include nitrates, coliform bacteria, sediment, and stream instability. As the watershed continues to urbanize, these problems will probably worsen.

Landuse and Hydrology

This map is a 1992 landcover map of the Walnut Creek Watershed and the surrounding area. The gray area is the urban portion of the watershed. This portion is rapidly increasing. If development continues without regard to the hydrologic changes it is forcing on the watershed, water quality will continue to degrade.

Historically, most of the watershed was prairie and wetlands with timber growing along the stream corridor. The prairie provided a great sponge and most of the rainfall that fell on the land was either used by the prairie vegetation or soaked into the ground. Very little water ever ran off the surface of the ground. What water did soak in seeped into the groundwater table and slowly traveled to the streams. This gave the streams a fairly consistent flow year round with water temperatures staying fairly moderate.

With the introduction of roofs, roads, parking lots, etc., the landscape has lost a considerable portion of its infiltration capacity. The ground is no longer a sponge, and most of the rainfall runs off the surface of the land and straight into a stormsewer. Consequently, today's streams are very flashy. They carry a considerable amount of water just after a storm event, and may run completely dry during the summer months.

Walnut Creek Watershed Project

Walnut Creek Watershed Project has three major objectives:

1)  Form a new partnership within Walnut Creek Watershed called the Walnut Creek        Corridor Alliance. This alliance are those businesses, mayors, elected officials, water utility personnel, schools, developers, the media and others who will commit to understanding their watershed. These key leaders can advocate for this project and the watershed, assist in building the public's awareness on watershed issues and help to create and support future initiatives.

2)  Form a volunteer cadre called Watershed Stewards. The Watershed Stewards will receive watershed information, have the opportunities to learn water-monitoring skills and assist in a tree inventory of their community. They will also train others to identify more directly with their watershed, their water resource, the vegetation and how it provides many benefits for clean water.

3)  Conduct an education and awareness campaign within Walnut Creek Watershed to increase the resident's awareness of the value and importance of the watershed, clean water, and riparian forest stewardship. This will be accomplished through neighborhood meetings, actual demonstrations, how to videos, newsletters, and informational literature, in cooperation with Drake University's Journalism and Mass Communication School.

If you live, work, play, or shop in the Walnut Creek Watershed and would like to get involved with this project email us.