improved assessment of nitrogen and phosphorus fate and transport for irrigated agricultural...

Mazdak Arabi, Ryan Bailey, Timothy Gates, Xiaolu Wei (PhD student)Dept. of Civil & Environmental Engineering, Colorado State University

Improved Assessment of Nitrogen and Phosphorus Fate and Transport for Irrigated Agricultural Watersheds in Semi-Arid Regions

1. Integrate SWAT with MODFLOW and UZF-RT3D to enhance simulation of surface-subsurface flow and reactive transport processes

2. Improve understanding of the processes that govern N and P movement, transformation, and storage in agricultural watersheds

3. Assess remediation strategies for N and P contamination in semi-arid agricultural watersheds under varying climate scenarios

4. Work closely with the SWAT development team to enable broad dissemination and use of the enhanced model

Project Objectives

Project Timeline

Modeling Framework

Principal Study Region

Additional Study Regions

Conceptual Model

Model Coupling HRU-Grid Linkage2013-2014 Modeling Framework / Field Work / Model Testing

2014-2015 Finish Model Testing / Assess Fundamental Processes

2015-2016 Remediation scenarios / Climate Scenarios

2016-2017 Remediation scenarios / Distribute Results (SWAT Team)

Lower Arkansas River Basin, Colorado

Upper Klamath Basin, OregonSWAT + MODFLOW + RT3D

Previous Results (MODFLOW + UZF-RT3D)

Model and code are open source and are now available. They can be obtained by contacting the project participants.

Little River Watershed, Georgia

Nitrate Groundwater Loading

SWAT + MODFLOW + RT3D

Dissemination of ModelConference Presentations Working with SWAT Modeling Team

June 2015 October 2015

1. Working on test watersheds (Little River, GA; Middle Bosque, TX)

2. SWAT-MODFLOW Workshop at SWAT Conference (Purdue University; October 13, 2015)

3. Developing User Interface (prepare MODFLOW model, SWAT-MODFLOW linkage)

Nitrate Concentration in Groundwater (UZF-RT3D)

Bailey, R.T., Gates, T.K., and M. Ahmadi (2014), “Simulating reactive transport of selenium coupled with nitrogen in a regional-scale irrigated groundwater system.” Journal of Hydrology515, 29-46.

Nitrate Groundwater Concentration

SWAT Model

MODFLOW Model

DEM Grid

HRU Grid

River Subbasins

Model Linkage

Water table elevation

Groundwaterdischarge