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Pollutant Load Ratio Estimation Tool (PRESTO)

Phosphorus tools

Point: Nonpoint Source Ratio (example graphic representation)

The Pollutant Load Ratio Estimation Tool (PRESTO) is a statewide GIS-based tool that compares the average annual phosphorus loads originating from point and nonpoint sources within a watershed. The comparison provides a screening tool for industrial and municipal dischargers to determine one of the conditions of eligibility for adaptive management as part of s. NR 217.18, Wisconsin Administrative Code.

PRESTO was designed to be easily modified, transparent to the end user and provide a consistent result based on readily available datasets. PRESTO performs three basic functions: watershed delineation, nonpoint source loading estimation and point source loading aggregation. The PRESTO outputs include a delineated watershed, watershed land cover composition, the estimated average annual nonpoint source and measured point source phosphorus loads (pounds per year), and the ratio of point to nonpoint phosphorus at a watershed outlet.

Is my facility in a nonpoint source phosphorus dominated watershed?

To be eligible for adaptive management, a facility must be located within a nonpoint source dominated watershed (greater than 50% of the total phosphorus load must come from upstream nonpoint sources such as agricultural or urban runoff). To assist with the phosphorus source question, PRESTO has been run for 652 municipal and industrial outfalls statewide using a three-year (2009-2011) average annual phosphorus discharge from each facility. To determine if your facility is located in a nonpoint source dominated watershed, thus meeting one of the adaptive management eligibility requirements, download the “Facility Eligibility Lookup” document, find your facility in the table, and look for the column labeled “Nonpoint Source Dominated?”

Learn more about the other adaptive management eligibility requirements.

PRESTO-Lite (Web application)

PRESTO-Lite is the web-based application of the tool requiring only a web browser with internet connectivity. With a click of the mouse, PRESTO-Lite summarizes upstream watershed characteristics including point and non-point phosphorus loads, landcover, modeled streamflow, and natural community type for any user-defined watershed within Wisconsin.

The PRESTO-Lite tool can be accessed via the Wisconsin Water Explorer (WEx). To view PRESTO-Lite results on WEx, select a waterbody, then the "Stream Tools" tab, then the PRESTO-Lite nested tab.

PRESTO (Desktop application)

For more complex analysis, a desktop version of PRESTO is available. Instructions for downloading and operating the software are included in the PRESTO Desktop User Manual.

PRESTO, Version 1.1 (March 2013)

DNR water quality models and training