• U.S. Department of the Interior• U.S. Geological Survey

Peter Claggett, Fred Irani, Renee Thompson, and David Donato

October 29, 2013Delaware Watershed Forum

Modeling Urbanizationin the

Chesapeake Bay Watershed

Chesapeake Bay Watershed, U.S.A.

Future Population in Chesapeake Region

IPCC SRES

1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 21000

10,000,000

20,000,000

30,000,000

40,000,000

50,000,000

60,000,000

A2B2A1B1Trend

Year

Po

pu

lati

on

(m

illio

ns

)

The Chesapeake Bay Land Change Model (CBLCM)

1. To provide the specific land-use data input needs for the Watershed Model, accommodating the best available regional data.

2. To inform restoration strategies and policies through simulating alternative future land use scenarios.

Purposes:

Total Maximum Daily Load (TMDL) allocation:The amount of nitrogen, phosphorus, and sediment that the Chesapeake Bay can receive while sustaining water clarity, dissolve oxygen, and chlorophyll-a levels that support living resources.

States and localities are required to implement Best Management Practices to reduce nutrient and sediment loads by 2025.

States and localities are required to maintain reductions forever.

The Bay TMDL: A Restoration Blueprint

1940 Housing Density1950 Housing Density1960 Housing Density1970 Housing Density1980 Housing Density1990 Housing Density2000 Housing Density

Updated analysis following methods outlined by Hammer, et al., 2004.

2010 Housing Density

Counties

Chesapeake Bay

Census Total Housing Units

Units per Acre

0.0 - 0.1

0.2

0.3 - 0.5

0.6 - 1.0

1.1 - 2.0

2.1 - 3.0

3.1 - 5.0

5.1 - 10.0

10.1 - 75.3

0

How does the CBLCM work?Population

ProjectionsEmployment Projections

Residential and Commercial Land Demand

Urban-----------Suburban---------------Rural

Density Assumptions

Land Suitable for development

Housing Projections

Infill/Redevelopment

US Census 1980 - 2010

Fine-scale Allocation and Simulation of Development

DevelopmentLocation, Extent, and

Patterns1984 - 2006

Probability of development

Factors Affecting Location of Growth

Probability (yr. 2010)

Legend

thu00_dens2.img

ValueHigh : 16.8061

Low : 0.00213435Low

High

Prince George’s County

Anne ArundelCounty

Housing Density(yr. 2010)

Housing Density(yr. 2100)

Legend

thu00_dens2.img

ValueHigh : 16.8061

Low : 0.00213435Low

High

Prince George’s County

Anne ArundelCounty

2010202020302040205020602070208020902100

Prince George’s County

Anne ArundelCounty

2100 v12100 v22100 v32100 v42100 v52100 v62100 v72100 v82100 v9…2100 v100

Prince George’s County

Anne ArundelCounty

Future Development (2040)Trend: Simulation #1

Future Development (2040)Trend: Simulation #2

Green Infrastructure (2006)Green Infrastructure (2040)Trend: Simulation #1

High

Low

Suitability

Green Infrastructure (2040)Trend: Simulation #2

Anne

Aru

ndel

Balti

mor

e

Calv

ert

Carr

oll

Cecil

Char

les

Fred

erick

Harf

ord

How

ard

Mon

tgom

ery

Prin

ce G

eorg

e's

St. M

ary'

s

Balti

mor

e

Adam

s

Berk

s

Ches

ter

Daup

hin

Lanc

aste

r

Leba

non

York

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

Core Forest Extent Pre- and Post-Development

yr. 2006 extentyr. 2040 extentA

cres

* Based on 23 simulations and use of the GUIDOS software. Brackets represent +/- 2 standard deviations from the mean

Chesapeake Bay Alternative Future Development Scenarios

Land-UsePlanning

Land Conservation

TREND

Weak

Strong

Weak Strong

SustainableChesapeake

Conserve Green

Infrastructure

Infill &Redevelopment

Laissez-Faire

Rural Down-zoning

BaselineInfillForest Conservation

Farmland Conversion to Development2006 - 2025

Baseline: - 433,347 acresInfill: - 377,931 acresConservation: - 468,738 acres

Farmland Loss

BaselineInfillForest Conservation

Forest & Wetland Conversion to Development2006 - 2025

Baseline: - 441,724 acresInfill: - 352,648 acresConservation: - 408,427 acres

Forest Loss