The MSDSS Partnership project's LTHIA Tools

LTHIA Main Page



Bureau of Science Services (Wisconsin DNR) has worked with the EPA-led Midwest Spatial Decision Support Systems Partnership to develop Web-based tools to support watershed management. These efforts, funded by a National Environmental Information Exchange Network grant, have resulted in new tools that allow automated tabular and spatial data discovery, exchange, integration, and analysis.

This collaboration between Purdue University, the Wisconsin DNR, and the Institute for Water Resources of Michigan State University provides tools to perform environmental analyses at the watershed scale.

Tools are available to evaluate land cover change scenarios, estimate nutrient runoff, prioritize sub-basins by erosion and sediment loading, evaluate BMP cost benefits, explore low impact development (LID) options, and map-browsing. Use the links below to access the system and learn about the tools.

To access the specific Purdue tools follow the links below.

The Institute for Water Research tools are available here.

  Purdue LTHIA and LTHIA LID Tools for MSDSSP Management System:

Google Maps Interface for Online Watershed Delineation. (Wisconsin)



LTHIA Low Impact Development Spreadsheet.



What is LTHIA:

Community planners, developers and citizens of a community should be aware of the long-term impacts of landuse change on their environmental resources. LTHIA, Long-Term Hydrologic Impact Assessment, is designed to help these people to quantify the impact of land use change on the quantity and quality of their water. This tool uses the land use and a soil characteristic from the user along with thirty years of precipitation data to determine the average impact that a particular land use change or set of changes will have on both the annual runoff and the average amount of several non-point source pollutants. For those unfamiliar with the hydrologic (water related) impacts of land use change this tool along with the supporting documents will hopefully give the user enough information to start asking questions about land use changes in their area.

[ How LTHIA works ]



Spreadsheet and OWL LTHIA

There are several input screens for Standard L-THIA (using TR-55 curve numbers), which are available below.

For residents of other EPA Region 5 states (Illinois, Ohio, Michigan, Indiana, Minnesota) , there is a GIS version which automatically categorizes landuse and soil based on your location. [ Online watershed delineation (OWL) and LTHIA ]

For those new to L-THIA and land use planning Basic Input is a good place to start. There are eight choices for land use types which most land uses fall into. For those familiar with land use planning terms or need to describe a custom land use, Detailed Input gives more land use options. The fourteen choices for land uses includes 6 lot sizes for residential housing and an option to define a custom land use. After using the Basic Input for a few analyses, a user would be able to use the Detailed Input. The advanced version of this allows customizing EMCs as well.

[ Basic Input LTHIA Spreadsheet ]

[ Detailed Input LTHIA Spreadsheet (custom Landuse) ]

[ Advanced LTHIA Spreadsheet (custom landuse and custom EMC table) ]


Fact Sheet for LTHIA

Powerpoint™ for Wisconsin Training Sessions

Powerpoint™ for LTHIA workshop

Fact Sheet for LID-LTHIA

Powerpoint™ for LID-LTHIA workshop

Tutorial exercise for hands-on training


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