Beaver Creek

Watershed Plan

Client

Beaver Creek WMA

Location

Central, IA

Completion date

October 2019

This Watershed Plan can be viewed is a comprehensive effort, addressing a wide variety of issues and outlines a long-term process to initiate progress to improving water quality and watershed health.

Civil Engineering & Water Resources

This watershed plan was prepared through a contract administered by Polk County, on behalf of the Beaver Creek Watershed Management Authority (WMA).RDG led a consultant team, which included EOR (St. Paul, MN) and Snyder & Associates (Ankeny, IA), to develop the plan. Stakeholder engagement had two focus group workshops, monthly steering committee meetings and quarterly WMA board meetings.

The majority of the data found on the EPA’s Water Quality Data download portal (formerly STORET) was collected by volunteers through the IOWAWATER program; the IOWAWATER program was discontinued in 2016.

Field and desktop methods were applied to evaluate stream bank stability within the Beaver Creek Watershed. This analysis yielded 1,315 high priority sites, grouped in 6 key areas.

The final plan included detailed strategic plans for each of 11 sub-watersheds. The plans included the optional mix of best management practices to achieve water quality and quantity improvement goals, with a cost projection.

Since watershed management authorities are “authorities without authority,” this plan depends on a mix of local communities, stakeholders and property owners to carry it out. Each community will need to take action to adopt the plan. Each jurisdiction will need to review its ordinances and policies to determine what changes are needed to carry out the recommendations of this plan. Projects will need to be incorporated into local budgets or alternative sources of funding (grants, etc.) pursued. Ongoing resources and staff will need to be committed to carrying out water quality monitoring and the education and collaboration plan.

Most of all, this plan needs champions – devoted local advocates who are committed to making sure that it is carried to its conclusion.

The Beaver Creek Watershed covers parts of Boone, Dallas, Greene, Polk and Webster counties. It includes 15 communities and many unincorporated areas. Beaver Creek generally flows from North to South.

1,315 high-priority sites were largely grouped within 6 key areas within the Beaver Creek Watershed. These sites demonstrate characteristics that have a high potential for poor stream health, biological integrity, and increased contribution to water quality degradation.

The total number of livestock in each subwatershed was estimated by the Iowa DNR animal feeding operation (AFO) database (Figure 8.5). The DNR AFO database is current to 2017 and the registered number of animals is known. AFO’s with less than 500 animal units (AU) are not required to register with the Iowa DNR or obtain a manure management plan. According to available information on the DNR website, there are 16 NPDES permits for wastewater treatment, including six municipalities operating wastewater treatment plants and 10 miscellaneous dischargers. The latter includes two Municipal Separate Storm Sewer Systems (MS4), six industrial dischargers, one Army National Guard Base, and one feedlot.

Nitrate loading rates in the watershed were estimated using values from the SWAT model that was constructed and calibrated for the Des Moines River, to which Beaver Creek is tributary. A unique annual loading rate was assigned to each subwatershed, with values ranging from 12.7 to 20.1 pounds per acre.