GISBased Hydrologic Modeling: Impacts of Land Use on Storm Runoff in Developing Watersheds

1
GIS-Based Hydrologic Modeling Impacts of Land
Use on Storm Runoff in Developing Watersheds

• Grant Benjamin Russell
• 2007
• University of North Carolina at Charlotte

2
Impacts of Land Use on Hydrology

• Urbanizing regions, such as the UNC Charlotte
  area, are increasingly being converted from
  pervious surfaces to impervious surfaces.

3
Study Area
4
Runoff Impervious Surfaces

• When precipitation is intercepted by buildings,
  parking lots, and roads, water is held in what is
  known as depression storage.
• Once this storage is exceeded, runoff occurs.

5
Runoff Pervious Surfaces

• Soils in and around the study area are clays and
  silty loams which have a low infiltration
  capacity
• Runoff occurs on pervious surfaces when
  infiltration capacity is exceeded

6
Objective

• To develop a model to estimate storm runoff
  within Toby Creek Watershed the UNC Charlotte
  campus area

7
Analytical Framework
Drayton et al (1992) Hydrological
Processes Slack and Welch (1980) Water Resources
Bulletin
8
Data Used

• Rasterized soils layer according to soil type
  using runoff curve numbers.

9
Data Used

• 1 meter resolution
• 4 band imagery
• R, B, G, NIR
• Classify Quickbird Image using supervised
  classification method and consolidated to 2
  classes
• Permeable Surfaces
• Impermeable Surfaces

10
Surface Cover

• Combine the land cover with the soils layer using
  a conditional statement.

11
Results

• Dark blue represents areas of high runoff
• Yellow represents areas of high infiltration

12
Results

• Impervious surfaces account for over half of Toby
  Creek Watershed
• Only 7 of the watershed has had little or no
  urbanization

13
Conclusion

• The Toby Creek Watershed has been highly impacted
  by urbanization
• Increased impervious surfaces has greatly
  accelerated runoff in this region
• Storm runoff will continue to increase as
  urbanizing watersheds continue to develop

14
Literature Cited

• Drayton, R. S. Wilde, B. M. Harris, J. H. K..
  Geographical Information System Approach to
  Distributed Modeling. Hydrological Processes,
  Vol. 6, (1992) pp. 361-368.
• Slack, R. B. Welch, R.. Soil Conservation
  Service Runoff Curve Number Estimates from
  Landsat Data. Water Resources Bulletin, Vol.
  16, No. 5 (October 1980) pp. 887-893.