Glass half full: A framework for setting realistic water quality conservation targets.

Abstract

A case study was launched to quantify potential water quality benefits attainable through practical and realistic conservation implementation targets. The Lake Michigan Basin was selected because of its importance as a dairy, grain, and oilseed production region that supports a range of ecosystems and endangered species. The objective was to build a framework, implementing a widely accessible tool that could be applied by local conservation staff to set practical, watershed-level, clean water targets. The US Environmental Protection Agency's Pollutant Load Estimation Tool, which is free and provides a user-friendly web interface, was applied to quantify phosphorus and sediment load reduction from six conservation scenarios in each Hydrologic Unit Code-8 watershed. Conservation scenarios included rotational grazing, cover crops, conservation tillage, nutrient management, prairie strips, and a combination of the practices referred to as "regenerative agriculture." Each scenario was compared to a baseline of current cover crop and conservation tillage adoption rates, established using remote sensing data. The model estimated that implementing the regenerative agriculture scenario, which would require an additional 2640 km² of conservation and $260 million in investment, could reduce phosphorus loads by 21% and sediment loads by 10% compared to current loading. Results confirm that conservation investments by multiple stakeholders at the federal, state, and local levels can result in meaningful impacts to achieve water quality goals. This framework can be applied to other regions with minimal data inputs, making it a scalable approach to guide collective action toward water quality conservation targets.