Integrating Land Use Planning into the CBP Phase 5 Watershed Model
& Tributary Strategies
Presented by:Peter Claggett, USGS
June 13, 2004
Maryland Department of Planning
Over the past decade in the Bay watershed:
• Population increased 8.2% and
• Impervious cover increased 40.7 %
“If recent trends continue, the area of developed land in the (Bay) watershed will increase by more than 60% by 2030.”
~ “Chesapeake Futures: Choices for the 21st Century”, STAC 2003.
Recent Growth Areas in the Chesapeake Bay Watershed
Areas of significant residential and impervious growth (1990 – 2000)
Nutrient and Sediment
Loads/ Uptake
Air Emissionsand
Deposition
WastewaterDischarge
(Pipe and Septic)
ImperviousSurfaces and
Runoff
Commercial/ Industrial
High DensityResidential
Low DensityResidential
Development Intensity Continuum
Health of the Bay
Chesapeake Bay Program’s Watershed Model
Hydrologic Simulation Program- Fortran Model (HSPF)
Limitations of the growth modeling capabilities in the CBP Watershed Model (Phase 4.3)
• Relies on 1970’s/1990’s hybrid land cover;
• Assumes uniform linear relationship between population growth and urban extent.
• Does not consider alternative land development scenarios;
Phase 4.394 segments
16 water qualitycalibration
stations
Phase 5.0697 segments
70 water qualitycalibration
stations
Use of finer scale and more current data
Use of finer scale and more current data
2000 Impervious Surface 2000 Land use/ Land cover
Number of workers Number of households
A better method for forecasting growth:
A decision support system that spatially allocates projections of future housing and employment and enables the exploration of alternative future development scenarios
HistoricalPopulation and Housing
Data(U.S. Census Bureau)
HistoricalEmployment
Data(Bureau of Labor Stats.)
Road & Impervious Data(GDT & Landsat)
Phase 5Watershed Modeling
Segments
1990 and 2000 Estimates ofResidential and Commercial
Development by
Watershed Segment
CBP Smart Growth Decision Support System
Baseline scenarioHistoric
urban growthestimates
Estimates of RegionalOffice Space
Requirements
RegionalEmployment
Forecasts
Estimates of County HousingRequirements
Smart Growth Policy Options1. Density constraints2. Environmental constraints
• Slope• Critical habitats• Prime farmland• Water supply protection areas
3. Infrastructure constraints• Sewer/water service areas• Road access
Baseline scenarioPolicy scenario APolicy scenario BPolicy scenario C
etc.
Spatial allocationof forecasted growth
to available land
Phase 5Watershed Modeling
Segments
2000 Land CoverData
(Landsat ETM)
County PopulationForecasts
CBP Smart Growth Decision Support System
Baseline scenarioPolicy scenario APolicy scenario BPolicy scenario C
etc.
EPA Needs-basedSewer Model
UpgradeCapital Cost
Scenarios
CBP Partner&
Tributary TeamEvaluation
AcceptableScenario
Smart Growth Policy Options1. Density constraints2. Environmental constraints
• Slope• Critical habitats• Prime farmland• Water supply protection areas
3. Infrastructure constraints• Sewer/water service areas• Road access
UnacceptableScenario
Chesapeake BayWatershed Model
(HSPF)
WaterQuality
Scenarios
Promotion of multi-jurisdictional planning;
Promotion of sound land use practices through tributary strategy implementation.
Simulation of alternative future development scenarios;
Benefits to the Chesapeake Bay Program Partnership
Evaluation of the water quality, infrastructure, and land conversion effects of smart growth policies;
Potential future improvementsof the
CBP Smart Growth Decision Support System:
• Couple with the Scenario Builder application to support the Tributary Strategies and model re-evaluation.
• Couple with more spatially explicit growth models (SLEUTH) and with environmental impact models for mobile air emissions (CALPUFF), and biodiversity conservation (NatureServe’s VISTA)
Thank you.