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Projected Development Pressure Through 2050 - Chesapeake Bay Watershed

Overview

Another 4.5 million people are expected to live in the Chesapeake Bay watershed by 2050. Where will these additional people live? How will that affect, or be affected by, land conservation efforts? This map illustrates the locations where development pressure is expected to be heaviest between now and 2050.

Data Layer Description

Source

Chesapeake Conservation Partnership, US Geological Survey and Chesapeake Bay Program

What this data layer represents

This map illustrates the locations where development pressure is expected to be heaviest between now and 2050. Specifically, the map projects the percentage of currently developable unprotected land in each HUC 12 subwatershed that could be converted to development by 2050. This information may be useful in understanding how development may influence -- or be influenced by -- land conservation and stewardship.

Location

Pennsylvania, New York, Delaware, Maryland, Virginia, West Virginia, and the District of Columbia.

Description

This map projects the percentage of currently developable, unprotected land in each HUC 12 subwatershed that could be converted to development by 2050. “Percent developed” is the average amount of forecasted development in acres divided by the area suitable for development--currently undeveloped, unprotected lands with no significant physical constraints (e.g. steep slopes). The darker the orange, the higher the percentage of projected conversion to development in the HUC12 subwatershed. In contrast, the grey areas are likely to experience minimal residential/commercial development pressure.


These data were developed using the Chesapeake Bay Land Change Model (CBLCM). For this map, the CBLCM used a scenario depicting the continuation of historic development trends. This scenario helps to assess the threat of development, i.e., development pressure, to forests and farms.  The specific metric, “Percent Developed”, provides an indication of the potential effectiveness of land conservation for avoiding or minimizing the extent of future forest and farmland conversion. For example, if 90% of suitable land in a HUC will be developed in the future, then land protection in that HUC specifically will likely reduce future growth.

The CBLCM is a computer simulation model designed to forecast future urbanization across multiple counties or states based on the best data and information available at regional scales. The CBLCM relies on county and state produced population and employment projections to determine the overall demand for growth. The model assigns a portion of that demand to infill and redevelopment based on recent county-level trends and allocates the remaining demand to the landscape in the form of residential and commercial patches (i.e., clusters of 30-meter resolution cells) of development. The U.S. Geological Survey began developing the CBLCM in 2012 specifically to inform decisions focused on restoring water quality and conserving habitat and open space in the Chesapeake Bay watershed.

The CBLCM is capable of simulating multiple future scenarios. Scenarios represent unique and logically consistent sets of assumptions about future conditions. For example, a “smart growth” scenario might involve greater investments in land conservation, stronger enforcement of zoning, and incentives to promote infill and redevelopment. For any given scenario, the CBLCM simulates 101 equally-likely spatial representations of residential and commercial development. For each iteration, the exact location of new development is randomly selected but the choice of location is influenced by probability of growth at any given location (generally higher close to already urbanizing areas) and by exclusion of steep slopes, protected lands, open water, and already developed lands. Therefore, overall growth patterns within a county are similar across all 101 iterations but exact locations of patches are variable. This is done to account for uncertainty associated with parcel-level representations of future growth.

How to get the data layer

Chesapeake Conservation Partnership contact: Jake Leizear, GIS Fellow, jleizear@chespeakeconservancy.org

How you might make use of this data layer

This map illustrates the locations where development pressure is expected to be heaviest between now and 2050 by HUC 12 subwatershed. This information may be useful in understanding where land conservation may have the greatest influence on future development patterns.

How to get more information

For more information about the Chesapeake Conservation Partnership contact: John Griffin, Program Manager, jgriffin@chesapeakeconservation.org

Access and use constraints

Attribution No Derivatives (BY-ND)

None

Credits

2018, Chesapeake Conservation Partnership, US Geological Survey & Chesapeake Bay Program

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