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Agricultural & Biological Engineering

Spatial Decision Support Systems (SDSS) Modeling Group


Welcome to the Spatial Decision Support Modeling Group in the Department of Agricultural & Biological Engineering at Purdue University. 

Online Tools Developed by Agricultural and Biological Engineering Purdue University with various cooperators and funders

Group 1: Landuse Change Impact on Runoff Models for EPA Region 5 - LTHIA variants, LID variant, BMP tools
Group 2: Hydrologic Models - Load Duration Curve, groundwater withdrawl
Group 3: Pesticide interactions - NAPRA
Group 4: Environmental Management - Purdue STEPL Web

Recent research using L-THIA

Optimal selection and placement of green infrastructure to reduce impacts of land use change and climate change on hydrology and water quality: An application to the Trail Creek Watershed, Indiana. (Liu et al., 2016)


About L-THIA

L-THIA (Long-Term Hydrologic Impact Assessment) has been developed as a straightforward analysis tool that provides estimates of changes in runoff, recharge and non point source pollution resulting from past or proposed land use changes. It gives long-term average annual runoff for a land use configuration, based on actual long-term climate data for that area. By using many years of climate data in the analysis, L-THIA focuses on the average impact, rather than an extreme year or storm.

L-THIA results do not predict what will happen in a specific year. As a quick and easy approach, L-THIA results are intended to provide insight into the relative hydrologic impacts of different land use scenarios. The results can be used to generate community awareness of potential long-term problems and to support physical planning aimed at minimizing disturbance of critical areas. It is an ideal tool to assist in the evaluation of potential effects of land use change and to identify the best location of a particular land use so as to have minimum impact on the natural environment of the area. Recent concern over urban sprawl has focused on several land use change issues, including the failure to account for hydrologic aspects of land use change that can result in flooding, stream degradation, erosion, and loss of groundwater supply.

L-THIA was developed to provide a quick, accessible tool to use in assessing the long-term impacts of land use change. This site suitability analysis tool makes use only of information that is readily available from municipal databases.

Development and Applications of the L-THIA Model

Initial applications of L-THIA involved assessing the impact of land use change on groundwater recharge, and of sub urbanization on runoff into a wetland in northeast Ohio (Harbor, 1994; McClintock et al, 1995). Ogden (1996) then applied the spreadsheet technique to town planning and coastal management in Barbados, and Bhaduri et al. (1997) used L-THIA to examine the hydrologic implications of future land use change for an urbanizing watershed in north-central Indiana, based on zoning maps.

Leitch (1997) and Leitch & Harbor (in review) followed up on Ogden (1996) to provide a detailed assessment of how urbanization and agricultural transition in the Hole town watershed (Barbados) changed runoff inputs to the coastal zone, including comparisons with existing stream flow data. Grove et al (in press) performed an extensive sensitivity analysis on the L-THIA approach, examining how the results of analyses varied with distributed versus composite CNs, the spatial resolution of the input data, and differing climate data record lengths.

Grove et al (accepted) then used a GIS version of L-THIA to examine the impact of historical land use change in a watershed in Indianapolis, using remote-sensing based land use maps, with a particular focus on spatial patterns of change within the watershed. Grove et al (accepted) also compared L-THIA predictions of runoff volume to river gauge data.

During the years of 2001 to 2008, applications of L-THIA include Minner’s (1998) analysis of variations in urban sprawl impacts for the major climate regions of the U.S., her assessment of the relative hydrologic impacts of conservation subdivision design versus traditional use patterns, and Minner et al’s (in press) analysis of how L-THIA and other hydrologic techniques can be used in the apportionment of costs as part of a fee system to support maintenance costs for a drainage management programs. In addition, Bhaduri (1998) performed comparisons of L-THIA with other well-known hydrologic models, and developed a non point source pollution routine for the GIS version of L-THIA that has been applied to an assessment of water quality impacts associated with past and planned land use change in a watershed in Indianapolis.

Intercampus Research Agreement, Indiana University (POLIS Center) - Purdue University (ABE)

Project Title:Deployment of Water Quality Decision Support Tools using Service Oriented Architecture (SOA) and Web 2.0 Development Approach

Brief Scientific Progress Report:
This project successfully designed a Web 2.0 “wrapper” for a popular online model and published the application development environment (API) for others to use to connect their web pages to this model.
The basic online model now displays its results over Google Maps ™, it allows a KML-based download for users to employ with Google Earth™ and streamlines the feeding of data from the first model to the following models.
Web applications based on Web 2.0 technology provides techniques to transfer information across firewalled or secure systems.  These innovations in interactive, online applications provide two-way flows of information between users and the Web, free-form organization of the content and complexities of models.  It allows interconnection of the systems on the Web via lightweight Web services like RSS, XML/HTTP, and REST. 


Team Head

Dr. Bernie Engel, Dept. Head ABE, Purdue University
Email: engelb@ecn.purdue.edu    


Professional staff

Larry Theller, Senior GIS Specialist
Email: theller@purdue.edu                                                                         


The Department's mission is to prepare students, citizens, and industry for the future through innovative education and extension/outreach programs and the discovery of knowledge. Our cross-disciplinary strengths include academic and research programs in agriculture, biology, and engineering, as well as dual degree programs.  Our engineering degrees are granted by the College of Engineering and our agricultural systems management degree is granted by the College of Agriculture

Purdue University
Agricultural & Biological Engineering
225 South University Streetx West Lafayette, IN  47907-2093       
Phone:  (765) 494-1162
Fax:  (765) 496-1115