1. Developing Modeling Tools in Support of Nutrient Reduction Policies Randy Mentz Adam Freihoefer, Trip Hook, & Theresa Nelson Water Quality Modeling Technical Team WDNR Bureau of Water Quality

2. Administrative Code NR 217 NR 151 A Modeled Approach

3. NR 217 Subchapter III Water Quality Based Effluent Limitations for Phosphorus NR 217 Subchapter III Water Quality Based Effluent Limitations for Phosphorus NR 151 Subchapter II Nutrient Management NR 151 Subchapter II Nutrient Management The Motivation

4. The Motivation: NR 217 Adaptive management eligibility Water quality criteria exceeded Point sources < 50% Filtration or equivalent technology required to meet water quality criteria NR 217 Subchapter III Water Quality Based Effluent Limitations for Phosphorus NR 217 Subchapter III Water Quality Based Effluent Limitations for Phosphorus

5. Pollutant Load Ratio Estimation Tool (PRESTO) PRESTO is a statewide GIS-based tool that calculates basin specific average annual phosphorus loads from point and nonpoint sources. Watershed Delineation Pollutant Runoff Effluent Aggregation

6. PRESTO – Overview Village of Almena WWTP Upstream Watershed: 32.9 mi 2 NonpointLoad Village of Almena WWTP Upstream Point PointSources 6% 16% 78% Point to Nonpoint Phosphorus Load Ratio 22% : 78% Point Source Red Cedar River Watershed (HUC 08, 1,890 mi 2 ) 20 Outfalls

7. PRESTO – Input Datasets Point Source : Nonpoint Source Load Ratio SWAMP Outfall Locations And Effluent Point Loads Elevation Land cover Hydrography Tabular Model Parameters Sub-basin Boundaries

8. PRESTO – Phosphorus Estimation Point Source Phosphorus Load Permitted sites with phosphorus monitoring data Average annual discharge & concentration calculated using that year’s monitoring record Nonpoint Source Phosphorus Loads Export coefficients Multiple regression models MR1 – Grassland within 30m riparian zone, forested land, & stream density MR2 – Cropland, urban land, & stream density

9. PRESTO – Outputs Output Attribute Categories Watershed Characteristics Land Cover Composition (%) Point Loading Nonpoint Estimation Model – Export Coefficient (EC) Nonpoint Estimation Model – Multiple Regression Model #1 (MR #1) Nonpoint Estimation Model – Multiple Regression Model #2 (MR #2) PS : NPS Ratio Per Nonpoint Estimation Model

10. PRESTO – Statewide Analysis

11. PRESTO – Documentation & Download PRESTO Version 1.0 Release includes: http://dnr.wi.gov/org/water/wm/ww/presto/ PRESTO Model Files User Manual Documentation, Validation, & Analysis Report Fact Sheet

12. NR 151 Subchapter II Nutrient Management NR 151 Subchapter II Nutrient Management The Motivation: NR 151 Identify fields / farms with Nutrient Management Plan need Evaluate the phosphorus index performance standard (PI = 6) per field Ensure soil conservation

13. WI Nutrient Targeting & Tracking Tool – Overview Develop a state-wide assessment tool to identify critical source areas of potential non-point sediment and phosphorus loss. Target fields at county or subwatershed scale Prioritize TMDL implementation efforts Manage agricultural practice & BMP data

14. WI Nutrient Targeting & Tracking Tool – Overview Mead Lake Watershed SWAT model Subwatershed Prioritization How do we determine field prioritization?

15. WI Nutrient Targeting & Tracking Tool – Concept Field-scale Prioritization Relies on rotation average P index (lb. P / acre / year) using established WI Phosphorus Index Requires significant amount of data Additional question that follows: If one field is improved, what is the water quality benefit at the subbasin outlet?

16. WI Nutrient Targeting & Tracking Tool – Approach 1 Develop Statewide Model Grid 2 Select watershed 5 In-Stream Transport 3 Calculate Grid-Specific Phosphorus Export Based on annual export from Snap-Plus model, other lands would rely on separate export calculations 4 Determine Delivery from Grid Cell to Stream

17. WI Nutrient Targeting & Tracking Tool – Approach Data Collection and Management To Support Cell Specific Export County Average Soil P Grid Tool Relies on Spatial Inputs Including: 30-meter gridPrecipitation NLCD Land coverSlope Land Management (Tillage, Rotation, Fertilizer) Flow Direction And Volume Soil PropertiesClosed Depressions Phosphorus Soil TestDistance to Waterway

18. WI Nutrient Targeting & Tracking Tool – Next Steps Develop framework for managing and tracking landscape data Beta test on watershed with existing field and stream data Determine impacts of using county average data

19. Summary The DNR has developed and will continue to develop modeling tools to support existing and future policy. Out of the box models such as SWAT and Snap-Plus may only get us so far towards our questions. PRESTO and Nutrient Targeting & Tracking Tool are screening tools, bridging the gap between no answer and a detailed analysis. Testing and validation of these tools ensures defensibility.

20. Questions? Contact the DNR Water Quality Modeling Team dnrwaterqualitymodeling@wisconsin.gov