The Headwaters of the St. Croix River includes waters of exceptional quality with 160 miles of streams and rivers,197 lakes, and almost 38,000 acres of wetlands. The major rivers are the St. Croix and the Eau Claire. These waters and the lands draining to them – the Headwaters Watershed – cover nearly 335 square miles in the Northern Wisconsin Counties of Douglas and Bayfield. The Headwaters ends where the St. Croix River is impounded by the Gordon Dam. Below the dam,the St. Croix River becomes the St. Croix National Scenic Riverway.

Upper St. Croix Lake is located roughly 10 miles upstream of the St. Croix Flowage and on the east shore of the town of Solon Springs, WI in Douglas County. Over the years, locals have expressed a concern that the high water in the Upper St. Croix Lake may be caused by backwater effects created by the operation of Gordon Dam, which is located on the downstream end of the St. Croix Flowage, also in Douglas County, WI. In the past 35 years, there have been a number of studies that investigated the possible reasons for high water levels on the Upper St. Croix Lake; however, none of them conclude that the high water levels are a result of the dam’s operations.

A watershed study was performed for the St. Croix Headwaters Watershed (SCHW), including areas upstream of Gordon Dam near Gordon, WI. The study focused on priority water resource issues identified through collaboration with the local sponsor and stakeholders. This included evaluating existing conditions for water quality; wetlands presence and function; aquatic habitat; fish passage; aquatic invasive species and St. Croix Flowage Management. Potential for future development was also assessed, including potential impacts of development on priority water resources. Finally, recommendations were made to direct future watershed management.

This project is part of a larger effort by the U.S. Army Corps of Engineers (USACE), Saint Paul District in partnership with the Wisconsin Department of Natural Resources (WIDNR) to study the Saint Croix Headwaters watershed. The purpose of this project was to map and describe the existing condition of wetland resources.

This report summarizes data collected for a hydrologic and water quality study of the Upper St. Croix – Eau Claire Rivers Watershed (USCECRW) conducted in 2008 and 2009. This study was designed to evaluate the current conditions in the USCECRW by monitoring 10 stream sites throughout the watershed, by collecting lake overturn, groundwater, and synoptic stream samples, by modeling the hydrology and water quality of the watershed, and by analyzing the build out potential within the watershed. The study was performed cooperatively by the Upper St. Croix Watershed Alliance, Wisconsin Department of Natural Resources, UW-Stevens Point Center for Watershed Science and Education, and U.S. Army Corps of Engineers.

As part of the lake and watershed management planning process, Center for Land Use Education (CLUE) conducted a residential build-out analysis for the USCECRW to identify future residential development potential in accordance with current land regulations. The results are displayed in two ways: for the entire watershed and within direct drainage areas. We used Geographic Information Systems (GIS) software, land information, and Community Viz™ to identify and quantify development constraints (i.e., land-based features that restrict future development) and land yet available for future development. Current zoning regulations (mapped at the parcel level) were applied to the net developable land to produce maps and tables of build-out numbers in terms of the total and location of potential residential development. Finally, future land use maps were created to reflect the watershed as if it were completely built-out. The process produced theoretical growth scenarios for the watershed based on development constraints and the effect of specific zoning regulations. In total, three build-out scenarios were generated taking into account various wetland alternatives. We used a range of data sources to identify potential wetland areas as possible constraints to development in addition to other environmental and physical constraints. Results of the build-out scenarios were incorporated into a Soil Water & Assessment Tool (SWAT) to quantify the potential water quality impact of allowable development in the watershed (included earlier in this report). This analysis is functional for generalized land and watershed planning, and is not meant for site specific applications such as plotting a subdivision. Areas that would be developed to provide goods and services to a larger population are not considered in this build-out analysis.

This report was written by Mr. William F. James, Eau Galle Aquatic Ecology Laboratory (EGAEL) of the Environmental Laboratory’s, Environmental Processes and Effects Division (EPED), U.S. Army Corps of Engineers - Engineer Research and Development Center (ERDC). Funding for this project was provided by U.S. Army Corps of Engineers District, St. Paul (USACE-MVD). Mr. Elliott Stefanik, USACE-MVD, was the lead project manager. The following people are gratefully acknowledged for participating in this project: Mr. Byron Karns, Department of the Interior, National Park Service, St. Croix National Scenic Riverway, and Mr. Aaron G. Carlson, Badger Technical Services, Inc., conducted field sampling and chemical analyses. Mr. Jacob Macholl, University of Wisconsin – Stevens Point, and Mr. Joe Schuler, U.S. Geological Survey, conducted flow measurements and continuous gauging of inflows to St. Croix Flowage, Ms. Nancy Turyk, University of Wisconsin – Stevens Point, was the project coordinator and lead investigator for the water quality assessment project of the St. Croix River Headwaters. Her team at UW-SP is gratefully acknowledged for providing water quality and gauging data for tributary loading analysis.

2747300 Upper Saint Croix Lake