Download the Rush River Hydrologic Study (pdf 4.6 mb)

Flood Control
A hydrologic model of the watershed was developed to analyze stormwater storage alternatives. The model builds on existing data available for the watershed—GIS mapping, contour data, ditch and tile mapping, anecdotal data about problem areas, and bridge and culvert replacement plans. Extensive field work has also been conducted so to better quantify existing conditions within the Rush River watershed.

The hydrologic model will be used to identify priority areas for stormwater storage and design key hydrologic parameters for these areas including:
* Normal and high water levels
* Wet and flood storage volumes
* Areas and durations of inundation
* Peak inflows and outflows
* Outlet configurations

Once feasible alternatives for storage implementation are identified, we will estimate the costs of recommended facilities, including easement costs. The primary goals of the hydrologic analysis are to identify strategic locations for storage and put a cost to the implementation of this storage.

Erosion and Sediment Control
The project included developing a photolog of portions of the main river channel. Originally this was to be a canoe expedition but widely fluctuating spring and early summer water levels precluded such a trip. Present low river levels suggest this may be a walking expedition. Existing instances of erosion areas, streambank instability, channel debris and blockages, and culvert outlets will be photographed and located using a GPS instrument. For existing erosion problem areas, we will provide structural and nonstructural recommendations, along with cost estimates.

Wetland Restoration
We will begin looking at storage solutions like where wetland restoration would complement recommended storage solutions. Historical wetlands that have been drained due to ditching or tiling are typically among the easiest to restore and also have the best success rate. The wetland seedbank and other characteristics necessary for wetland success are frequently still in place in these drained wetlands.

As part of this study, we are using National Wetland Inventory maps, hydric soils mapping, ditch and tile line maps, and historical aerial photos (where available) to identify potential sites of historical wetlands. These will be combined with local knowledge of past wetlands and activities that may have affected them.

Wetland areas provide water quality and habitat benefits beyond what stormwater ponds can provide. The goal of intergrating wetland restoration into the storage program is to realize some of these additional benefits.

Water Quality
We will incorporate water quality treatment of stormwater into the design of the stormwater storage areas where possible and appropriate. To that end we have been reviewing water quality data obtained through the ongoing RRAP monitoring program.

Cropping and Tillage Practices
Our hydrologic modeling incorporates information on cropping and tillage practices. Our modeling will also quantify benefits associated with large scale changes in these practices. Changes in tillage practices, or better put, an extension or already used conservation tillage practices is another aspect (along with storage) to a comprehensive approach to both flooding and water quality.
The product of this work will be recommended residue cover within high priority areas of the watershed and their associated impact on downstream water quality.

Citizen Involvement
The hydrologic assessment involves regular meetings with county board members and other stakeholders to present results and obtain input and feedback. Stakeholder input will guide the final report to recommendations that make sense at the local level.