1. Modeling Urbanization
in the
Chesapeake Bay Watershed
Peter Claggett, Fred Irani, Renee Thompson, and David Donato
October 29, 2013
Delaware Watershed Forum
•U.S. Department of the Interior
•U.S. Geological Survey

2. Chesapeake Bay Watershed, U.S.A.

3. Future Population in Chesapeake Region
60
Population (millions)
50
40
IPCC SRES
A2
30
B2
A1
B1
Trend
20
10
0
1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
Year

4. The Chesapeake Bay Land Change Model
(CBLCM)
Purposes:
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.

5. The Bay TMDL: A Restoration Blueprint
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.

6. 2010
2000
1990
1980
1970
1960
1950
1940 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
Updated analysis following methods outlined by Hammer, et al., 2004.

7. How does the CBLCM work?
Population
Projections
Housing
Projections
Employment
Projections
Infill/
Redevelopment
Density
Assumptions
Land Suitable for
development
Residential and Commercial Land Demand
Factors Affecting
Location of Growth
US Census
1980 - 2010
Urban-----------Suburban---------------Rural
Development
Location, Extent, and
Patterns
1984 - 2006
Probability of
development
Fine-scale Allocation and Simulation
of Development

8. Value
Probability (yr. 2010)
High : 16.8061
High
Anne Arundel
County
Low
Low : 0.00213435
Prince George’s
County

9. Value
Housing Density
(yr. 2010)
2100)
High : 16.8061
High
Anne Arundel
County
Low : 0.00213435
Low
Prince George’s
County

10. 2100
2090
2080
2070
2060
2050
2040
2030
2020
2010
Prince George’s
County
Anne Arundel
County

11. 2100 v1
v100
v9…
v8
v7
v6
v5
v4
v3
v2
Anne Arundel
County
Prince George’s
County

12. Future Infrastructure (2006)
Green Development (2040)
Trend: Simulation #1
#2
Suitability
High
Low

13. Core Forest Extent Pre- and Post-Development
180,000
* Based on 23 simulations and use of the GUIDOS software. Brackets represent +/- 2 standard deviations from the mean
160,000
140,000
120,000
100,000
80,000
yr. 2006 extent
yr. 2040 extent
60,000
40,000
20,000
York
Lebanon
Lancaster
Dauphin
Chester
Berks
Adams
Baltimore
St. Mary's
Prince George's
Montgomery
Howard
Harford
Frederick
Charles
Cecil
Carroll
Calvert
Baltimore
0
Anne Arundel
A
c
r
e
s

14. Chesapeake Bay Alternative Future
Development Scenarios
Strong
Infill &
Redevelopment
Land-Use
Planning
Sustainable
Chesapeake
Rural Downzoning
TREND
LaissezFaire
Conserve
Green
Infrastructure
Weak
Weak
Land Conservation
Strong

15. Farmland Conversion to Development
2006 - 2025
Forest
Infill Conservation
Baseline
Farmland Loss
Baseline:
- 433,347 acres
Infill:
- 377,931 acres
Conservation: - 468,738 acres

16. Forest & Wetland Conversion to Development
2006 - 2025
Forest
Infill Conservation
Baseline
Forest Loss
Baseline:
- 441,724 acres
Infill:
- 352,648 acres
Conservation: - 408,427 acres