A Watershed Process to Quantify and Facilitate Ecosystem Improvements through Flow Regime Restoration

The ecological integrity of the Great Lakes has declined due to a number of factors including water withdrawal, physical habitat modifications, and changes in land use. Research has shown that restoring the watershed's natural flow regime is an essential element in restoring impaired fisheries and other beneficial aquatic resources. This paper presents a process that focuses on restoration of a watershed's flow regime and quantification of the resulting ecosystem improvements. This process was developed for the Great Lakes basin but it is transferable to other ecoregions. The methodology recognizes that water quality, habitat, and various human factors affect watershed management decisions, but emphasizes flow regime as the main restoration goal for watershed management decisions that will lead to ecosystem restoration. The basic premise is that absent the necessary hydrology, the presence of all other factors would not be sufficient to restore aquatic biota. This correlation between flows and the ecosystem has been well documented. The process includes an accounting system and protocols to quantify hydrologic improvements resulting from changed land and water practices and a process to facilitate flow regime restoration transactions. Two pilot watersheds are analyzed: (1) Upper Rouge River watershed, near Detroit, Michigan and (2) Menomonee River watershed, near Milwaukee, Wisconsin. The potential users of this process include landowners, public management authorities, and private entities that need to evaluate land and water management decisions to generate resource improvements. The process is relevant to many resource improvement drivers, such as the public relations value of demonstrating good stewardship, stormwater regulations, smart growth, compensatory restoration for natural resource damages, leveraging of private funding sources, and formulation of alternate environmental projects in lieu of monetary penalties to mitigate negative impacts. The results indicated that the methodology provides a quantification tool for flow regime restoration using stormwater best management practices (BMPs). Potential market-based implementation incentives for flow regime restoration BMPs were identified.