improved assessment of nitrogen and phosphorus fate and transport for irrigated agricultural...
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Improved Assessment of Nitrogen and Phosphorus Fate and Transport for Irrigated
Agricultural Watersheds in Semi-Arid Regions(2013-2017)
Project Director: Mazdak ArabiCo-PD: Ryan T. Bailey
Co-PD: Tim Gates
PhD Student: Xiaolu WeiPhD Student: Seonggyu Park
Dept. of Civil and Environmental EngineeringColorado State University
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Project OverviewNitrogen and Phosphorus Transport in Semi-Arid Regions
1. Enhance the capacity of the SWAT model to simulate N and P transport in semi-arid irrigated agricultural watersheds
2. Improve understanding of the processes that govern N and P movement, transformation, and storage in irrigated agricultural watersheds
3. Assess viable remediation strategies for N and P contamination
4. Disseminate the new modeling tool to the research community
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
1. Improve SWAT Model
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Linking 3 Models:
SWAT
MODFLOW
RT3D
Land Surface ProcessesStream Processes
Groundwater FlowGW-SW Interactions
Chemical TransportMass Loading to SW
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Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
1. Improve SWAT Model
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Linking 3 Models: SWATMODFLOWRT3D
Water Table
Runoff
Volatilization canal
PumpingWell
Vadose ZonePercolation,
N, PConcentration
Overland flow
and transport
Lateral
FlowStream stage
Solute transport
Root Zone Processes
Groundwater discharge Groundwater flow
Uptake
ET
Confining Layer
Plant Growth
N, P mass loadingN, P reactive transport
Transport
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
1. Improve SWAT Model
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SWAT MODFLOW / RT3D
HRUs
Grid Cells Recharge / NO3, P
Channels Stream Stage
River Cells
GW Discharge
NO3, P conc.
NO3, P Loading
• HRU-Grid Linkage: GIS Pre-processing routines
• SWAT-MODFLOW-RT3D: single FORTRAN code
• Daily time step
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand ProcessesModel Applied to 3 Watersheds
Sprague River Oregon
4,100 km2
Arkansas River Colorado
500 km2 470 km2
Middle Bosque River Texas
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand Processes
MODFLOW Model (USGS)
Sprague Watershed
SWAT-MODFLOW-RT3D
- 1970-2004- Water table elevation- Stream discharge- NO3 concentration- In-stream NO3 loading
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand Processes
Annual Average Recharge
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand Processes
Average Groundwater NO3 Concentration
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand Processes
Groundwater Discharge to Streams
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand Processes
Average Annual NO3-N Loading to Streams
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand Processes
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand ProcessesArkansas River, Colorado
• Designate each cultivated field as an HRU
• Incorporate canal seepage
• Include N and P concentration in irrigation water
• Assess N and P storage in soil, groundwater, riparian areas
• Investigate influence of climate (e.g. drought)
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand ProcessesField Data Collection
• 22 Groundwater monitoring wells• 8 surface water sites
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand ProcessesField Data Collection
• 22 Groundwater monitoring wells• 8 surface water sites
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand ProcessesArkansas River, Colorado
What are the timing and amount of N and P loading at various locations along the main river and its tributaries?
What influence do spatially-variable aquifer properties and irrigation practices have on flow paths of N and P mass and subsequent timing of N and P loading to surface water bodies?
What is the overall influence of irrigation chemistry on N and P mass in groundwater and surface water?
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand ProcessesArkansas River, Colorado
Each field is an HRU
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand ProcessesArkansas River, Colorado
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
2. Understand Processes
MODFLOW-RT3D Model Results
Improve SWAT Model
Disseminate Tool
3. Assess Viable BMPsArkansas River, Colorado
BMPs to Analyze:• Fertilizer reduction (uniform and targeted)• Increased irrigation efficiency• Canal sealing• Rotational fallowing• Riparian enhancement
Assess BMPs
Understand Processes
(15-30%)(10-20%)
(0-20%)(15-25%)
(5-10%)
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
4. Disseminate Modeling Tool
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1.Conference Presentations
2.Workshops & Tutorials
3.Tools (User Interface)
4.Website
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
4. Disseminate Modeling Tool
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1. Conference Presentations2. Workshops & Tutorials3. Tools4. Website
• SWAT Conference (2015) Purdue• AGU Hydrology Days (2015, 2016) CSU• SWAT Conference (2016) Beijing• AWRA Conference (November 2017)
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
4. Disseminate Modeling Tool
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1. Conference Presentations2. Workshops & Tutorials3. Tools4. Website
• SWAT Conference (2015) Purdue• AGU Hydrology Days (2015, 2016) CSU• SWAT Conference (2016) Beijing• AWRA Conference (November 2017)
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
4. Disseminate Modeling Tool
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1. Conference Presentations2. Workshops & Tutorials3. Tools4. Website
SWATMOD-PrepGraphical User Interface
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
4. Disseminate Modeling Tool
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1. Conference Presentations2. Workshops & Tutorials3. Tools4. Website
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
4. Disseminate Modeling Tool
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1. Conference Presentations2. Workshops & Tutorials3. Tools4. Website
SWAT-MODFLOW Google Group127 Members (since 2015)
Assess BMPs
Improve SWAT Model
Understand Processes
Disseminate Tool
4. Disseminate Modeling Tool
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Current Collaborations with SWAT-MODFLOW-RT3D• Ogallala Aquifer Region (CSU, Texas Tech Univ., Univ. of Nebraska)
• South Platte River Basin (CSU)
• Little River Watershed, Georgia (CSU, USDA-ARS)
• Western Alberta, Canada (University of Alberta)
• Dee River Watershed, Wales, United Kingdom (Swansea University)
• Central Germany (University of Kassel)
• Tigris-Euphrates River Basin (Clemson University)
• Limpopo River Basin, Botswana (South Dakota State University)
• Australia (Flinders University)
• Buenos Aires, Argentina (Plains Hydrology Institute)
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Summary1. New Modeling Tool (SWAT-MODFLOW-RT3D) (Oct. 2015)
• GW level, GW flow, soil water, stream discharge
• Nutrient concentration in GW and stream water
• Nutrient mass loading between aquifer and streams
• Nutrient mass storage in soils and aquifer
2. Application of Model to 3 Watersheds (OR, CO, TX)
3. Next 2 years: more results for CO and TX watersheds
4. Model being used by research groups worldwide