1. Long-Term Hydrologic Impact Assessment (L-THIA) Model An overview / screening model User friendly tool Does not require detailed data input Identifies need for more detailed modeling Provides "What-If" alternatives evaluation scenarios

2. charge Curve Number (CN) based approach Uses 30 years of precipitation data to predict yearly runoff Precipitation data is used to estimate the Antecedent Moisture Content (AMC) in the soil, the CN is adjusted accordingly Event Mean Concentration (EMC) is used to estimate Non Point Source (NPS) pollution L-THIA Model concepts

3. Soils Land use Data requirements and components for analysis in L-THIA Curve Number values Daily precipitationLocation Runoff depths NPS pollutants map Runoff volumes map User supplied information Performed by L-THIA

4. charge L-THIA WWW in a spreadsheet version that models runoff and nps pollution changes L-THIA GIS - set of Avenue scripts that automate the process of runoff impact modeling within ArcView L-THIA GIS WWW allows interactive mapping of the area of interest with a custom java interface within a web browser Availability at present…

5. charge Availability of L-THIA (http://www.ecn.purdue.edu/runoff) online spreadsheet version Downloadable Avenue codes executable within ArcView online GIS version

6. charge Land use and hydrologic soil group provided by user and long term daily precipitation data queried from ORACLE database. LTHIA/NPS generates runoff and NPS pollution output in tabular and graphical representations - bar and pie chart form Development of the L-THIA WWW System

7. charge Java, JavaScript, ArcView Internet Map Server (IMS), Netscape Server and Avenue Scripts in ArcView are used. URL Request by Java Applet  Netscape Server  URL parse by ArcView IMS  Execute ArcView Avenue Scripts in LTHIA/NPS GIS Development of the L-THIA GIS WWW System