1 / 23

Urban Forestry and the Clean Water Act

Urban Forestry and the Clean Water Act. David J. Nowak USDA Forest Service, Northern Research Station Syracuse, NY. Outline. I-Tree Hydro Chesapeake analyses. i-Tree - Hydro. Management model designed to be relatively easy to use

kieve
Download Presentation

Urban Forestry and the Clean Water Act

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Urban Forestry and the Clean Water Act David J. Nowak USDA Forest Service, Northern Research Station Syracuse, NY

  2. Outline • I-Tree Hydro • Chesapeake analyses

  3. i-Tree - Hydro • Management model designed to be relatively easy to use • Object-oriented, physical based, semi-distributed, topographic model • TOPMODEL theory is used to simulate saturation excess overland flow (for forest area), base flow and ET process • Warm weather, semi-distributed urban soil-vegetation-atmosphere transfer scheme (SVATS) • C++ code with GIS inputs

  4. i-Tree Hydro Strengths • Specifically designed to incorporate urban tree and impervious surface effects on stream flow and water quality • Built to simulate the dynamic forest interception, infiltration and ET processes as well as urban impervious effect on runoff generation. • Calibrated against measure stream flow data • Relatively easy to use

  5. i-Tree Hydro Weaknesses • Lacks capabilities of fully-distributed model • Currently does not allow for specific locational designs of tree cover, impervious cover, or retention/detention ponds (operates on general cover types) • Works on watershed basis (with gauging station)

  6. Model Inputs • Hourly discharge data (USGS) • Digital elevation map (USGS) • Hourly weather and evaporation data • Evaporation data calculated from weather data • Structural information on watershed (NCLD and i-Tree Eco (UFORE) data) e.g., • Tree cover • Impervious cover • Shrub and grass cover • LAI

  7. Model Calculations • Topographic index with tree and impervious cover • Interception routine • Canopy parameters (throughfall, storage capacity, daily leaf and trunk area) • Depression storage (impervious) • Evaporation and transpiration from vegetation, soil and water surfaces • Infiltration into soils • Subsurface, overland and impervious runoff

  8. Model Outputs • For each time step (1 hour for these simulations): • Canopy interception • Depression storage • Infiltration • Evapotranspiration • Surface and subsurface (base flow) runoff • Channel discharge (total runoff)

  9. Water Quality • Separate program with inputs from i-Tree Hydro files • Multiple options that incorporate universal soil loss equation; buildup wash off routines • Currently only using EMC • Many other options need more input data • Dissolved sediment / solid pollutant load • Septic load • Dissolved pollutant concentration

  10. Preliminary Model Results • Watersheds • Accotink (Washington, DC) • Baisman Run (Baltimore, MD) • Gwynns Falls (Baltimore, MD) • Mill Creek (Lancaster, PA) • Rock Creek (Washington, DC)

  11. Baisman Run

  12. Baisman Run CRF1 = 0.56 CRF2 = 0.63 CRF3 = 0.70 Red – Observed; Black - Modeled

  13. Baisman Run Canopy held at 70% Impervious held at 10%

  14. Accotink

  15. Accotink CRF1 = 0.67 CRF2 = 0.56 CRF3 = 0.74 Red – Observed; Black - Modeled

  16. Accotink – Storm Simulations 2 year storm 10 year storm 50 year storm

  17. Water Quality Results (median national pooled EMC)

  18. Water Policies – Total Maximum Daily Load (TMDL) • over 40% of our assessed waters still do not meet the water quality standards of the Clean Water Act • TMDL specifies the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards • urban vegetation may help keeping urban waterways below TMDL limits

  19. On-Going Work • Cross comparisons with Larry Band • 2005 and 2007 Pond Branch • Other watersheds across US

  20. Questions?

More Related