SWAT was developed to predict the impact of land management practice on water, sediment and agricultural chemical yields in large complex watersheds with varying soils, land use and management conditions over long periods of time.
Soil and Water Assessment Tool (SWAT) is a watershed scale model originally developed by Dr Jeff Arnold for the USDA Agricultural Research Services. It was designed to predict the impact of proposed or alternative land management practices on water, sediment and agricultural chemical yields within complex watersheds of varying soils, land use and management conditions over extended periods of time.
The model operates on a daily time step, it is process based, computationally efficient, and capable of continuous simulation over long time periods. SWAT has the capability of incorporating a number of differing physical processes (major model components) in water shed modelling, these include;
Land Phase of the Hydrologic Cycle
Also considered is the routing phase of the hydrologic cycle;
SWAT - Flow Calibration
SWAT is a public domain model actively supported by the USDA Agricultural Research Service at the Grassland, Soil and Water Research Laboratory in Temple, Texas, USA. In modelling a watershed may be partitioned into a number of sub-watersheds which are then further subdivided into hydrologic response units (HRUs) that consist of homogeneous land use, management, topographical, and soil characteristics. The HRUs are represented as a percentage of the subwatershed area and may not be contiguous or spatially identified within a SWAT simulation. Alternatively, a watershed can be subdivided into only subwatersheds that are characterized by dominant land use, soil type, and management.
This catchment model is able to quantify the impact of land management practices on flow and water quality. As a result the model has widespread use internationally, including New Zealand, in informing land use planning, water quality guide lines and water allocation limits. The only limitation of SWAT then being the quality and amount of input data required to set up modelling on a given catchment study area.
|Latest Version||SWAT2012 re.664 released December 2016|
|State of Development||Stable Release|
|Current Development Activity||Active development by USDA and various research organasations.|
|Intended End Users||Specialist modellers supporting land and water managers|
|Temporal Extents||Years, Decades|
|Steady State or Dynamic||Dynamic|
|Operating Systems||MS Windows|
|User Interface||Please Select|
|Ease of Use||Moderate|
|Use in Policy Process||Plan (Policy Formulation), Do (Policy Implementation)|
SWAT Documentation: https://swat.tamu.edu/documentation/
|Support||No formal support. Training workshops are run regularly and there is an annual SWAT conference.
|Users Forum||Forum available|
|Programming Language||Fortran for the main engine code. ArcSWAT is written in a .net language|
|Methods included for calibration and validation||Calibration tools are provided in the SWATCUP tool from Eawag|
SWAT Water Movement
|Keywords||soil, water, sediment, chemical, land use, land management
SWAT Model Home Page - http://swatmodel.tamu.edu/
SWAT: Soil and Water Assessment Tool https://www.youtube.com/watch?v=AkVG_YccsVI
SWAT publications: https://swat.tamu.edu/publications/
An OpenMI compliant version is being developed, see http://www.openmi.org/reloaded/users/compliant-software/SWAT-IHE.html http://www.openmi.org/reloaded/news/OpenMI-Hype-Community.pdf
HydroModeller version available. SWAT home page - http://swatmodel.tamu.edu/
SWAT Calibration/Validation Publications > SWAT: MODEL USE, CALIBRATION, AND VALIDATION. https://swat.tamu.edu/media/90102/azdezasp.pdf
SWAT Publications: https://swat.tamu.edu/publications/
Ekanayake, J.C.; Davie, T. (2005). The SWAT model applied to predicting nitrate fluxes in the Motueka catchment. Motueka Integrated Catchment Management Report Series. Landcare ICM Report No. 2004-2005/04. Landcare Research. Lincoln, New Zealand. - http://icm.landcareresearch.co.nz/knowledgebase/publications/public/SWAT_modelling_N-04-05.pdf
University of Waikato: LERNZ - Catchment modelling with SWAT- https://www.lernz.co.nz/uploads/swat-fact-sheet.pdf
ICM's aim was to integrate research and management to address multiple issues; there were 5 key themes and areas of research associated with the Motueka project.
The Motueka River basin drains an area of 2075km2 providing ~65% of the major freshwater flow into Tasman bay.
Modeling of N fluxes in Motueka River (Tasman): http://icm.landcareresearch.co.nz/knowledgebase/publications/public/SWAT_modelling_N-04-05.pdf
Discharge and contaminant load - Waipa Stream, Rotorua (Bay of Plenty): Me, W., & Abell, D. P. H. J. M. (2017) Simulating discharge and contaminant loads from the Waipa Stream catchment under different irrigation scenarios using the SWAT model. Client report prepared for Rotorua Lakes Council. ERI report No. 98, Faculty of Science and Engineering, University of Waikato.
International Case Studies