The Michigan EnviroImpact Tool is part of the Regional Runoff Risk Decision Support Tools Network (multi-state collaborative). This is a risk assessment tool that identifies when and where there is a high likelihood of surface water runoff occurring. The information is presented on a color-coded map (indicating Low-Medium-High risk of surface runoff).

The Michigan EnviroImpact Tool map shows the assessment of day-to-day runoff risk across Michigan using National Weather Service (NWS) forecast models that consider predicted precipitation, forecast temperature, soil moisture content, snow accumulation and snowmelt forecasts. These models are updated daily to account for changes in weather forecasts and soil moisture conditions over short time periods. The results are then utilized to produce the maps that appear online.

Forecasters with the NWS North Central River Forecasting Center utilize components of existing NWS models (Sacramento Soil Moisture Accounting (SAC-SMA) Interflow time series; Rain + Melt (RAIM) time series; and Upper Zone Tension Water Deficit (UZTWD) time series) to analyze predicted precipitation looking forward 5 days and predicted temperature looking forward 10 days. The resulting model data is then forwarded to the Institute of Water Research at Michigan State University where the information is processed and predicted runoff volumes categorized to produce the maps which are then posted online and updated each day.

As part of the process of developing the regional runoff risk forecast tools, simulated runoff events based on the model predictions were compared to actual runoff event data collected by researchers from the United States Geological Survey (USGS) and the University of Wisconsin from 11 sites around the state (4 field scale sites and 7 USGS gauged watershed basins). Those results were encouraging and continued refinement of the model should yield even more accurate results as additional data are collected. Remember however, that the risk levels shown on the map illustrate average predicted conditions across the watershed basin. Individual field conditions will vary and must be considered every time a nutrient application is planned.

No. The Michigan EnviroImpact Tool is just one more tool that farmers and others who apply nutrients to Michigan croplands can use when deciding where and when to apply manure. Individual knowledge of local field conditions is absolutely critical to making well informed decisions about nutrient applications. Some fields, because of their slope, proximity to water resources, or other factors can be high risk for nutrient applications at all times while others are not. Soil moisture in individual fields will vary due to rainfall, snowpack, field aspect, and a large number of management factors. Each of these conditions will vary across the landscape and should be factored into a spreading decision.

No. The map is not a regulatory mechanism. It is being provided as another tool to help Michigan farmers, manure haulers, and nutrient applicators make informed decisions about when to land apply manure or other nutrients. Michigan Department of Agriculture and Rural Development has no intentions of using this forecasting tool for regulatory purposes.

No. The forecast tool should be considered a work in progress. As weather forecasting tools and methods become more accurate and additional edge-of-field and stream gauge information becomes available for forecast validation exercises, the regional runoff risk decision support team will continue to refine the forecasting tool. Much of the future refinements to the MI EnviroImpact Tool website will be based on comments received from potential users of the product. We encourage users to please continue to check the website and let us know what you think, what is working and where you see things we can improve.