Upload
lamdiep
View
214
Download
0
Embed Size (px)
Citation preview
Urban Forestry and Water Quality Assessment Tools
Vincent VerweijAMEC Earth & Infrastructure
Contact Ian Hanou at:[email protected] or303‐742‐5320
Tree Canopy and Water Quality
• Catches rainfall• Reduces peak flow of runoff
• Stores harmfulpollutants
• Reduces soil erosion, reducing sedimentpollution
Overview of Models
• CITYGreen
• i‐Tree Hydro
• EPA Stormwater Management Model
• Western Washington Hydrology Model
CITYGreen
• GIS and Excel‐based tool• Calculates the ecological and economic benefits provided by trees and other green space
• Analyzes replacement cost of urban canopy loss• Uses locally‐based reference data for benefitestimates
• Current Vs. Future condition comparison• Currently not supported for ArcGIS 10
CITYGreen Input
• Location• Land Use• Cost for replacement of tree function
CITYGreen Input
• Air Quality Reference City: Cincinnati
• Hydrologic Soil Type “C”
• Hamilton County Digital Elevation Model, resampled to 5-meter resolution
• Land cover raster configuration in CITYgreen and associated curve numbers (CN)
between 0 and 100 where a higher CN indicates higher imperviousness and runoff): Impervious Surfaces: Unpaved: Dirt (CN 87), Impervious Surfaces: Paved: Drain to sewer (CN 98), Cropland:
Row Crops (CN 82), Meadow: Continuous grass, generally mowed, not grazed (CN 71), Trees: Impervious
understory (CN 91), Trees: Grass/turf understory: Ground cover > 75% (CN 72), Trees: Forest litter
understory: No grazing, forest litter and brush adequately cover soil (CN 70), and Water (CN 100).
• Replacement land cover: Urban: Commercial/Business (CN 94)
• Construction cost: $3.00/cubic foot
CITYGreen Output
Water Runoff and Pollution
Air Pollution and Carbon Storage
i‐Tree Hydro
• Part of larger i‐Tree suite• Uses GIS and USGS elevation data to calculatehydrologic aspects of the study area
• Canopy‐oriented: Uses variety of canopycharacteristics in its calculations.
• Generates reports on Impervious flow, Sediment, heavy metal, nutrient runoff and oxygen content
i‐Tree Hydro
• Targeted by Cincinnati Parks for adoption of several strategies to reduce peak flow rates out of the basin.
• Study examines the expected impacts of reforestation of other land cover, and improvement of understory, on flow rates
i‐Tree Hydro Input
• Elevation Data (USGS)• Landcover Percentages• Study Area size• Percentage Evergreen Cover• Hydrologic Parameters of Study Area (optional)
i‐Tree Hydro Input
i‐Tree Hydro Input
Raw Data Inputs Location
WS. Area (square meters)
Percent Tree Cov. LAI
Percent Evergreen Start Date End Date
Cincinnati, Hamilton County, OH 11,002,648 47.6% 5 1.0% 2/3/2010 11/25/2010
Surface Cover Types Percent
Cover Types Beneath
Tree Cover PercentTree 47.6% Shrub 0.0%Shrub 0.5% Herbaceous 0.0%Herbaceous 21.1% Soil 90.0%Water 0.0% Impervious 10.0%Impervious 29.9% --Soil 0.9% --Total 100.0% Total 100.0%
Initial Data Inputs
i‐Tree Hydro Output
Runoff Flow
Pollution Increase
EPA Storm Water Management Model (SWMM)
• Full‐fledged hydrologic analysis tool• Analyzes benefits of a variety of Best Management Practices
• Returns values on stormwater runoff and pollution
• Single‐event to long‐term (continuous)• Requires significant knowledge of hydrologic modeling
• Not focused on tree canopy alone
SWMM Input
• Area• Slope• Landcover (Impervious)• Elevation Data• Stream gauges• Weather data• Stream Network
– Width– Depth– Base Flows
SWMM Interface
Coarse Scale - Bull Run Watershed, Fairfax, VA
SWMM Interface
Fine Scale – Street Project
SWMM Simulation Output
Western Washington HydrologyModel (WWHM)
• Hydrologic model specialized to King County, home to metropolitan Seattle and Puget Sound
• Similar to SWMM in complexity• Puts more emphasis on vegetation
– Takes into regard local forest makeup
• Uses Long‐term rainfall data
WWHM Coverage
Seattle
WWHM Inputs
• Land Use:– Pervious: forest, pasture, lawn– Impervious: roads, roof tops, driveways, sidewalks, and parking lots
• Soil Type• Watershed• Local hydrologic parameters
WWHM Output
Renton, WA, hydrologic analysis
Summary
• CITYGreen– Direct dollar values, fairly minimal work
• i‐Tree Hydro– Quick simulation with runoff values with some GIS work
• SWMM– Full hydrologic analysis, requiring in‐depth expertise
• WWHM– Localized hydrologic model with focus on vegetation
Summary/Questions
• CITYGreen– Provides report in dollar values, for easy communication, requiring relatively little expertise
• i‐Tree Hydro– Quick simulation with runoff values with some GIS workrequired. Still in Beta production
• SWMM– Full hydrologic analysis, not necessarily focused on forestry, but very powerful analysis
• WWHM– Localized hydrologic model with focus on vegetation and forestry
Contact Information: