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Thief River WatershedHydrological Simulation Program – FORTRAN (HSPF) Modeling
Stephanie Johnson, Ph.D., P.E.
Thief River Watershed WRPP Stakeholder Meeting
February 20, 2013
Scope of Work• Develop a model of the Thief River watershed
– Address: hydrology, sediment, and conventional pollutants
• Use local data as much as possible; supplement with state/federal data
• Model outcomes used to inform Phase II of WRPP work
Work with RLWD to fully integrate model into WRPP project
Why Model?• Simulate current conditions
– Extend understanding of water quality (spatially/temporally)
– Estimate loads at un‐gauged
locations
• Predict future conditions– Estimate impacts of “what if” scenarios on water quality
throughout the study area
• Bridge Phase I of the WRPP work with Phase II– i.e., bridge data collection with developing restoration/
protection strategies
Hydrological Simulation Program –FORTRAN (HSPF)
• Developed and supported by USGS/EPA
• Commonly used in TMDL/water quality analyses
• Basin‐scale, continuous‐time model
• Runs at an hourly time step; though interpreted on longer‐scale
• Can simulate existing and future conditions
• Data intensive/complex model with multiple components
Basic Model InputsInputs:
• Hydrography• Digital elevation model• Weather data• Soil properties• Land cover
Modeling Base
• 87 sub‐basins
• 7 weather stations– precipitation, solar
radiation, wind speed, air temperature, cloud cover, evaporation, dew point temperature
• 6 major reservoirs
• 2 wastewater treatment plants
• Model timeframe: 1/1/1995 – 12/31/2006– Warm‐up period: 1995
– Calibration: 1996‐2000
– Validation: 2001‐2006
Model Outputs
• For each sub‐basin– Yield of water, sediment, nutrients
• For each reach– In: flow, sediment load, nutrient load, etc.
– Out: flow, sediment load, nutrient load, etc.
• For each waterbody/reservoir– In: flow, sediment load, nutrient load, etc.
– Out: flow, sediment load, nutrient load, etc.
– Internal: volume
CalibrationCalibration ‐ the process of modifying the input parameters to a model until theoutput from the model matches an observed set of data (i.e., the model reflects“real world” conditions).
USGS Station: 05076000
Thief River near Thief River Falls, MN
Calibrating HydrologyThief River Falls USGS Gauge Station
Early attempt
Calibrated
Validating HydrologyValidation ‐ the process of verifying the model by comparing its output to observeddata during a time period other than that used for calibration.
Water Quality• Sediment calibration: Spring 2013
• Water quality calibration: Early summer 2013– Temperature, nutrients, BOD, dissolved oxygen, and algae
Dissolved Oxygen, Turbidity
Dissolved Oxygen
Dissolved Oxygen
E.coli, Ammonia
Calibrate at 6 water quality
stations
Example Output: Avg Sediment Yields
Example Application: BMP Effectiveness
Base Conditions
50’ Filter Strips
Example Application:Impacts of BMPs
at Watershed Outlet
ScenarioAvg
Streamflow(acre‐feet/yr)
AvgSediment
Load (tons/yr)
Avg TPLoad
(pounds/yr)
Baseline: Existing conditions (2003‐2008) 175,000 7,640 71,200
1a: 50’ filter strips 175,000 5,510 41,600
1b: 100’ filter strips 175,000 4,820 35,300
2min: Minimum ag land to permanent cover 175,400 7,350 67,500
2max: Maximum ag land to permanent cover 180,000 4,280 59,700
3a: Partially implemented side‐inlet control 180,000 5,530 58,500
3b: Fully implemented side‐inlet control 180,000 5,400 57,200
Example Application:Impacts of BMPs at Thief River entering ANWR from North
ScenarioAvg
Streamflow(acre‐feet/yr)
AvgSediment
Load (tons/yr)
Avg TPLoad
(pounds/yr)
Baseline: Existing conditions (2003‐2008) 69,055 2,133 20,545
1a: 50’ filter strips 69,055 1,353 7,637
1b: 100’ filter strips 69,055 678 4,872
2min: Minimum ag land to permanent cover 69,123 2,116 19,813
2max: Maximum ag land to permanent cover 70,688 1,018 11,555
3a: Partially implemented side‐inlet control 70,848 858 11,251
3b: Fully implemented side‐inlet control 71,006 759 10,948
Summary• Using HSPF to model the Thief River Watershed
• Finished with hydrology calibration
• Sediment and water quality to be completed by mid‐summer
• Use in Phase II of WRPP to:– Identify priority sub‐basins for management
– Run BMP scenarios
– Design effective restoration / protection strategies
