Development of techniques to quantify effective impervious cover.

Details

• Creators:
  Janke, Ben ; Gulliver, John S. ; Wilson, Bruce N.
• Corporate Creators:
  St. Anthony Falls Laboratory
• Corporate Contributors:
  University of Minnesota. Center for Transportation Studies
• Subject/TRT Terms:
  • Runoff
  • Surface drainage
  • Watersheds
  • Drainage practices
  • Moisture barriers
  • Impervious area, Moisture barriers, Runoff, Stormwater,
  • Aggressive waters, Watersheds
• Publication/ Report Number:
  CTS 11-20
• Resource Type:
  Tech Report
• Geographical Coverage:
  Minnesota
• Corporate Publisher:
  University of Minnesota. Center for Transportation Studies
• Abstract:
  Practitioners responsible for the design and implementation of stormwater management practices rely ; heavily on estimates of impervious area in a watershed. However, the most important parameter in determining ; actual urban runoff is the “effective” impervious area (EIA), or the portion of total impervious area that is directly ; connected to the storm sewer system. EIA, which is often considerably less than total impervious area and can vary ; with rainfall depth and intensity, is likely not determined with sufficient accuracy in current practice. A more ; accurate determination of EIA in a watershed would benefit a wide range of organizations involved in the design of ; stormwater management, pollution prevention, and transportation structures. ; This study investigated two existing methods of estimating EIA in a watershed: (1) analysis of large ; rainfall-runoff data sets using the method of Boyd et al. (1994), and (2) overlay analysis of spatial (GIS) data, ; including land cover, elevation, and stormwater infrastructure, using the method of Han and Burian (2009). The ; latter method provides an estimate of connected pavement, but requires the user to input the value of connected ; rooftop to determine the actual EIA value, which is the sum of these two quantities. The two methods were applied ; to two urban catchments within the Capitol Region Watershed in St. Paul, MN. The results were used to evaluate ; the potential of each method and make recommendations for future studies. ; In summary, the data analysis technique (Boyd et al., 1994) has the advantage of being quick and relatively ; simple to implement, as it did not require familiarity with specialized software tools (e.g. ArcGIS) and could be ; completed with any spreadsheet program with graphing capabilities (e.g. Excel). The EIA estimates from the data ; analysis are the most accurate, but the technique is unable to determine where in the watershed the EIA is located, ; and cannot be used if runoff discharge and local precipitation data is unavailable. By contrast, the GIS method ; (Han and Burian, 2009) has the advantage of being applicable to un-gauged watersheds, and also provides the ; location of EIA in the watershed. This latter feature makes it particularly attractive for honing the development and ; placement of BMP’s in a watershed. Unfortunately, the accuracy of the GIS method is completely dependent on the ; ability to faithfully represent the amount of roof connection in a watershed, a process that can add significant time ; and expense to the EIA estimate.
  More +
• Format:
  PDF
• Funding:
  CTS Project #2011076
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/23247/dot_23247_DS1.pdf
• File Type:
  [PDF - 4.10 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:a4bc6d03d3e2b5b2b6ce09e969e721c9c791cd0ab30ee3b58feb82d7b002ef4600fcdbf7fe87f6369140c7271670c844290184fb61ac11c876c3390439cce188