Workshop for Workshop for Watershed Watershed

Management Using Management Using Web-Based Decision Web-Based Decision

Support ToolsSupport Tools

Bernard A. EngelBernard A. Engel

Jin-Yong ChoiJin-Yong Choi

ToolsTools

• Web-based Watershed Delineation

• L-THIA: Long-Term Hydrologic Impact Assessment

• SEDSPEC: Sediment and Erosion Control Planning, Design and SPECification Information and Guidance Tool

Web GIS Based Web GIS Based Online Watershed Online Watershed

Delineation CapabilityDelineation Capability

Bernard A. EngelBernard A. Engel

Jin-Yong ChoiJin-Yong Choi

• Watershed: A basin, drainage or catchment area that is the land area that contributes runoff to an outlet point

Outlet pointWatershed boundary

Rain

Runoff

What is WatershedWhat is Watershed

What is Watershed DelineationWhat is Watershed Delineation

• Watershed Delineation: Define the watershed boundary based on topographical information about an outlet point

• Outlet point: A point on a stream or river of interest.

Why we need Watershed Delineation Why we need Watershed Delineation (WD) capability(WD) capability

• Need to understand target area and its features that are related with hydrologic phenomena to be analyzed at outlet point (e.g. peak runoff)

• Control boundary (watershed) is needed to gather hydrologic data including soil, land use, weather

• Watershed delineation is first hydrologic analysis step

Methodology (1)Methodology (1)

• Traditional Approach– Hand drawn on a

paper topographic map– Contour line

(Continuous line for the same elevation points) use

– Requires experience and labor

– Analogue approach– Manual

Outlet point

Methodology (2)Methodology (2)

• Using DEM and desktop GIS software– Digital Elevation Model (DEM): Grid format,

Each grid has elevation (altitude) value– GIS: Geographic Information System:

Computer program for digital mapping– Possible automatic data preparation

• WebGIS tools– WWW + GIS: Yahoo Map, MapQuest– Preprocessed data, limited functionalities

Where to begin?Where to begin?

http://pasture.ecn.purdue.edu/~watergenhttp://pasture.ecn.purdue.edu/~watergen

Display FunctionsDisplay Functions

Main Menu

Layer ControlOn/Off

Map Display

Display ControlZoom in/outPan, Full extent

Auxiliary Functions

Reference Map

WD Submit Button

Using the SDSSUsing the SDSSIndian Creek, Tippecanoe County, IndianaIndian Creek, Tippecanoe County, Indiana

Outlet point selected

Results PageResults Page

Using the SDSSUsing the SDSSIndian Creek, Tippecanoe County, IndianaIndian Creek, Tippecanoe County, Indiana

Watershed Delineation:Watershed Delineation:Indian Creek, Tippecanoe County, IndianaIndian Creek, Tippecanoe County, Indiana

Run hydrologic models- Impervious Area - L-THIA- SEDSPEC- Peak Runoff Estimation

Results Page Results display

Download and Print MapDownload and Print Map

Using the SDSSUsing the SDSSIndian Creek, Tippecanoe County, IndianaIndian Creek, Tippecanoe County, Indiana

On-line Digitizing Tool:On-line Digitizing Tool:Indian Creek, Tippecanoe County, IndianaIndian Creek, Tippecanoe County, Indiana

Land Use Change Using On-line Digitizing Tool and Run L-THIA

Land Use Change Using On-line Digitizing Tool and Run L-THIA

Land Use Change Report after Digitizing

Land Use Change Using On-line Digitizing Tool

On-line Digitizing Tool:On-line Digitizing Tool:Indian Creek, Tippecanoe County, IndianaIndian Creek, Tippecanoe County, Indiana

Land Use Change Using On-line Digitizing Tool and Run L-THIA

Land Use Change Report after Digitizing

Scenario 1: Before Change

Scenario 2:After Change

On-line Digitizing Tool -> Input PreparationOn-line Digitizing Tool -> Input PreparationIndian Creek, Tippecanoe County, IndianaIndian Creek, Tippecanoe County, Indiana

Thank you !Thank you !

http://pasture.ecn.purdue.edu/~watergenhttp://pasture.ecn.purdue.edu/~watergen