Nutrient Calibration Plan

1. Nutrient Calibration Plan Gary Shenk 6/7/05 Modeling Subcommittee

2. Time Line • Potomac phase 5.0 • Potomac Calibration only, due by the end of the June, hand calibration • Phase 5.0 • The rest of the watershed, due by the end of July, hand calibration • Phase 5.x • To come out periodically over the next 18 months, with advances in calibration methods and input data

3. Nutrient Calibration Edge of Field BMP factor Edge of Stream Land Acre Factor Delivery Factor

4. Nutrient Calibration Edge of Field • Based on Targets acquired from 3 sources: • Literature Survey • Sparrow analysis of land use • Mass Balance

5. Nutrient Calibration Edge of Field • Calibration Methodology • Calibrate for small trend in nutrient storage and to hit the targets • Based on experience with phase 4 • Hundreds of parameters controlling export, but only a few that are sensitive

6. Export Export Export Export Export Export Export Nitrogen Cycle in Watershed Model Forest After HSPF documentation Trees Denitrification Roots Leaves Nitrate Atmospheric Deposition Particulate Particulate Solution Labile Refractory Ammonia Organic N Organic N Solution Solution Adsorbed Labile Refractory Ammonia Organic N Organic N

7. Export Export Export Export Export Export Export Nitrogen Cycle in Watershed Model Forest After HSPF documentation Trees Denitrification Roots Leaves Nitrate Atmospheric Deposition Particulate Particulate Solution Labile Refractory Ammonia Organic N Organic N Solution Solution Adsorbed Labile Refractory Ammonia Organic N Organic N

8. Forest Harvested Forest Low Intensity Pervious Urban High Intensity Pervious Urban Low Intensity Impervious Urban High Intensity Impervious Urban Bare-construction Extractive Natural Grass High Till with manure Nut Man High Till with manure Low Till with Manure Nut Man Low Till with manure High Till without manure Hay with nutrients Nut Man Hay with nutrients Hay without nutrients Alfalfa Nut Man Alfalfa Pasture Nut Man Pasture Trampled Animal Feeding Operations Nursery Land Uses Simulated

9. Differences between p4 and p5 • Phase 4 used a combination of coefficient modeling (PQUAL) and mass balance modeling (AGCHEM). Phase 5 will be all mass balance modeling • Phase 4 reset the mass balance at the end of each year to stabilize the simulation. In phase 5, we will attempt to stabilize without resetting • Parameters governing nutrient uptake will change during the simulation to reflect crop makeup.

10. Nutrient Calibration Edge of Field BMP factor Edge of Stream Land Acre Factor Delivery Factor

11. Nutrient Calibration BMP factor Land Acre Factor Data Sets Under Development

12. Nutrient Calibration Phosphorus similar to sediment? Assume nitrogen targets are already EOS? Take land-to-river and small stream delivery factors from Sparrow? Delivery Factor

13. Nutrient Calibration Initial river calibration will be similar to the sediment calibration methodology Calibration by hand Determine sensitive parameters Determine calibration rules

14. Nutrient Status • 1-2 days away from being able to run the simulation • Still need some inputs, but we can start calibrating while we are waiting • Expect to have Potomac calibrated to an initial state with reasonable inputs by the end of June