Black Turtle Land Use Change Hydrologic Impact Evaluation Kyoung Jae Lim, Bernard A. Engel, Jin-Yong Choi, Jon Harbor, Larry Theller Purdue University Ag. and Biological Engineering Purdue University

Black Turtle Pre-development Post-development Urban Sprawl

Black Turtle Impacts on Hydrology Time Direct Runoff (Volume) Urbanized Area Detention basin Natural Eventually, “increase” in 1. Peak flow 2. Direct runoff after urbanization

Black Turtle Why L-THIA Model ? 3 Urbanization and land use changes sometimes inevitable 3 Thus, careful planning is necessary to reduce/minimize impacts of urbanization 3 Tools needed to assess effects of urban sprawl on environmental problems and create sustainable land use plans.

Black Turtle L-THIA Model 3 L ong- T erm H ydrologic I mpact A ssessment (L-THIA) model developed for such needs 3 Easy to Use/Easy to Obtain Data for Model  Efficient for “ What-if ” Scenarios (what happens if ‘A’ is located at one location vs. another ?)

Black Turtle Three Versions of L-THIA 3 L-THIA WWW GIS System: only requires web browser + internet access 3L-THIA Desktop System: Windows stand-alone program 3L-THIA component modules: modelbuilder version, Python version

Black Turtle L-THIA Model Inputs 3 Land Use Information 3 Soil Information (Hydrologic Soil Group) 3 Long-Term Daily Rainfall Data  Can  Can download long-term daily rainfall data from L-THIA WWW site for any location in the continental U.S Easy to Obtain Input Data Easy to Obtain Input Data!

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L-THIA Model Run 3 Annual Average Runoff Depth using L-THIA Estimated Values 3 Runoff Depth for Single Storm using Curve Number (CN) Method 3 Nonpoint Source (NPS) Pollutant Loadings using Event Mean Conc. (EMC) Values

Black Turtle Estimates Direct Runoff 3 L-THIA model estimates annual average direct runoff. 3 Thus, need to separate direct runoff from measured stream flow, when evaluating model 3 Web-based hydrograph separation model, called “WHAT” available.

Black Turtle How Good is L-THIA ? VERY WELL 3 L-THIA estimates match measured direct runoff separated from USGS daily stream flow VERY WELL.

Black Turtle Web-based L-THIA 3 L-THIA Web Version

Black Turtle Web-based L-THIA 3 Run L-THIA from Text Input form 3 Output name 3 State 3 County 3 Area unit 3Scenario name 3Land use and hydrologic soil group selection 3Menu 3Area input

Black Turtle Web-based L-THIA 3Run L-THIA from Online Automatic Watershed Delineation 3https://engineering.purdue.edu/~lthia

Black Turtle Web-based L-THIA 3View Control and Run Watershed Delineation 3Run Watershed Delineation 3Results Page

Black Turtle Web-based L-THIA 3Input Page from Watershed Delineation 3Automatically Filled in 32 more scenarios available 3Run L-THIA

Black Turtle edit Web-based L-THIA 3Run L-THIA and Results Map View 3Run L-THIA !! Edit landuse View in Google Maps Download data

Black Turtle Web-based L-THIA 3Output Pages Output results page -Uses hierarchical menu for runoff, NPS -Tables, Charts (Bar, Pie) -Probability of Exceedance Annual series output Annual series of direct runoff and NPS loading Probability of Exceedance

Black Turtle Low Impact (LID) L-THIA Low Impact Development (LID) practices aim to reduce the impacts of stormwater and pollutants created by land development. The goal of LID is to maintain, as closely as possible, the predevelopment hydrologic regime for new developments, or move toward the original hydrologic regime in existing urban areas.

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Low Impact (LID) L-THIA

Black Turtle Low Impact (LID) L-THIA

Black Turtle BASIC LID Screening

Black Turtle Lot Level LID Screening

Black Turtle Desktop L-THIA

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SUMMARY 3 Versions of L-THIA System Very Efficient in Assessing Impacts of Urbanization on Water Environment (compared to other complex models, while providing reasonable accuracy) 3 Very Easy to Use / Easy to Obtain Model Input, (compared to other complex models, while providing reasonable accuracy) 3 Available from -