Prioritizing stabilization projects using streambank erosion inventories in the Fox-Wolf River Basin

Project Overview

In 2020, the Wisconsin Department of Natural Resources (WDNR) developed a Total Maximum Daily Load (TMDL) for the Upper Fox and Wolf River (UFW). A TMDL is a calculation of the maximum amount of a pollutant that a body of water can absorb and still meet water quality. The TMDL was utilized in the creation of the EPA’s Nine Key Elements (9KE). Within the 9KE there is a requirement for reductions in pollution to meet water quality goals. The goals within this plan are to reduce Total Phosphorus (TP) which also relates to the reduction of Total Suspended Solids (TSS) such as erosion and flooding.

Approximately 34% of the reduction from the TMDL needs to come from the Winnebago Waterways Recovery Area with 51% of that reduction assigned to agriculture. Alteration in farming practices and structural changes will help make reductions.

Currently, streambank erosion has not been accounted for within required reductions in the TMDL. In some watersheds, we anticipate streambank erosion being a significant contributor to the total TMDL agricultural load. We need to inventory the streambanks in each HUC12 so that we can estimate potential TP/TSS reductions that could come from stabilizing streambanks to stop streambank erosion and to prioritize project locations. Stabilizing streambanks would be paired with efforts to increase infiltration on the land to reduce the volume and rate of flow that damages streambanks during storm events.

For this project, we will begin by completing streambank inventories in the four highest loading HUC12s located within the WWRA. The pollutant load from these HUC12s significantly contributes to water quality impairments of the streams within each HUC12, the Winnebago Lakes, and Lake Michigan. In addition to providing loading estimates from streambank erosion, this project also seeks to identify and prioritize potential locations for future restoration projects to help reduce nutrient loading and protect or enhance existing habitat. Going forward, this project will serve as a template for completing future streambank inventories for the remaining 28 HUC12s located in the WWRA.

Target HUC12 Subwatersheds in the 2023 Streambank Erosion Inventory

HUC12 to be Inventoried HUC12 Code Stream Miles

Town of Dale-Rat River 040202022102 60

Eldorado Marsh-Fond Du Lac River 040302020204 63

Lake Poygan – Willow Creek 040302022006 88

Pipe Creek – Frontal Lake Winnebago 040302020303 91

Project Timeline

In the Spring of 2023, a method was developed using GIS to determine streambanks to be physically inventoried as they are representative of the HUC12 they are located in. The method developed has been recorded in SOP#1: Streambank Erosion Inventory Desktop Review so it can be duplicated.

Fieldwork was accomplished in the summer of 2023. Streambank information from the desktop review was utilized to complete a physical inventory of these sections.

December 2023 – February 2024: Streambank Inventory Data Analysis was developed along with the extrapolation. These tools will allow an estimation of sediment loss and load & phosphorus loss and load for an entire watershed.