Introducing Web-Based Decision Tools for Environmental Watershed Management

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Introducing Web-Based Decision Tools for
Environmental Watershed Management

• Bernie Engel and Roxanne Mitchell
• Agricultural Biological Engineering
• Purdue University
• engelb_at_purdue.edu
• 765.494.1198

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Outline

• L-THIA (Long-Term Hydrologic Impact Assessment)
• SEDSPEC (peak rates of runoff and erosion and
  runoff structures)

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Long-Term Hydrological Impact Assessment (L-THIA)
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40
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Land Use Decisions Affect Runoff, Recharge, and
Water Quality
Natural Cover
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75-100 Impervious
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35-50 Impervious
30
55
30
15
35
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Rivers Drying Up
Rivers Flooding
Water Polluted
Stream Banks Eroding
Most communities respond to this with a mix of
reactive and proactive strategies, including
planning
Stream Ecology Changing
Wells Running Dry
Wetland Habitat Shrinking
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L-THIA

• Based on the rainfall land cover runoff
  analysis method already used in many communities
• Input Land Use Pattern(s) Soils Pattern
• Process Daily Runoff and Pollutant Loading
  Calculations (30 years)
• Output Average Annual Runoff and NPS loads for
  Specific Land Use Patterns

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A little history.

• Northeast Ohio, 1992 Our wetlands are failing
• Local Planners Need model to assess impact of
  land use change on hydrology.
• Reality Available models were data intensive
  and complex and getting more so.
• The Aim To develop a user-friendly model using
  basic available data for land use and soils, in
  response to the needs of planners and local
  environmental groups.

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L-THIA

• Originally a simple spreadsheet program
• Now a simple web tool
• GIS extension version also available

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So how do you do it?

• L-THIA Web

http//www.ecn.purdue.edu/runoff/lthianew
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Run L-THIA from Text Input form

• State
• County

• Land use and hydrologic soil group selection

• Area input

• Click Next

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Tables and charts for interpretation
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How is L-THIA Used?

• Near Columbus, OH significance of urbanization
  on runoff and water quality
• Triangle Park, NC comprehensive land use plan
• NASA KSC, FL impacts of historical land use
  change
• Northeast OH land use planning policy
  assessment wetland protection
• Indianapolis, IN historical impacts
• Kokomo, IN TMDL development

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SEDSPEC Introduction

• SedSpec assists in analyzing runoff and erosion
  problems
• Provides information about runoff and erosion
  control structures
• Provides peak runoff estimation using
• Rational method
• TR55

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What you can do using SEDSPEC

• Peak Runoff Estimation
• Preliminary erosion control structures design and
  selection
• Channels (Grass Lined, Riprap Lined, Concrete
  Lined, Open)
• Culvert
• Sediment Basin
• Level Terraces
• Storm Water Detention Basin
• Runoff Diversion
• Low Water Crossing

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Where you start

• pasture.ecn.purdue.edu/sedspec
• pasture.ecn.purdue.edu/watergen

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Summary

• L-THIA
• SEDSPEC
• http//www.ecn.purdue.edu/runoff/lthianew
• http//pasture.ecn.purdue.edu/sedspec