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.