Modeling the Impact of Urban Scenarios in the Chesapeake Bay Watershed

Renee Thompson and Peter Claggett USGS Chesapeake Bay Program Office Annapolis, Maryland

Alternative Futures: Accounting for Growth in the Chesapeake Bay Watershed

U.S. Department of the Interior September 15, 2011 U.S. Geological Survey

Outline

. Why alternative futures? . Trends in urban development . Examples of things we could model . Prototype infill scenario . Initial findings . Conclusions

U.S. Department of the Interior U.S. Geological Survey Why Do Alternative Future Scenarios? . There is no guarantee that what happened in the past will happen in the future (trend). . The future is full of uncertainties . Economic . Weather . Climate . Demographic shifts . Preference shifts . Scenarios bound the estimates of the extent of development and associated impacts on water quality. . It is “good” science

U.S. Department of the Interior U.S. Geological Survey Growth and Development – Why Infill? . Growing population = need for more homes!

U.S. Department of the Interior U.S. Geological Survey Chesapeake Bay Program (2009): http://www.chesapeakebay.net/photos Increasing consumer demand for communities with “” attributes Survey respondents are more likely to prefer compact, mixed housing communities that are walkable and amenity rich. Demand for these types of communities is increasing with changing demographics and preferences especially for singles, empty nesters and Gen X and Y. . Robert Charles Lesser & Co. LLC

U.S. Department of the Interior U.S. Geological Survey Chesapeake Bay Program (2009): http://www.chesapeakebay.net/photos NEW TRANSIT INCREASES PROPERTY VALUES PORTLAND, OR

Original cost - $54M Catalyzed Investment - $3.8B

Multiplier – 74X SOURCE: RCLCO, Reconnecting America

Used with permission 3 RCLCO WASHINGTON, D.C. STREETCAR PRIVATE FUNDING FOR NEW INFRASTRUCTURE Private Financing Taskforce - • Residential property values near streetcar would rise 5% to 12% • Commercial property valuations rising by 2% to 10% • Value of existing real property in the District would increase by $5B-$7 B • Will add $5B to $8B in new property • Adds $13.2 M in annual retail sales tax after ten years • Adds $71.4M per year in income tax in 10 years

Used with permission 13 RCLCO

Transit Oriented Development

. Urban planners and smart growth advocates have touted Transit Oriented Development (TOD) as a key to successful efforts to increase urban density. . Clustering higher density mixed-use development within proximity to a transit station. . People are willing to walk up to .5 miles from their homes to a transit station but that .25 miles is an ideal distance (Flint, 2005).

U.S. Department of the Interior U.S. Geological Survey http://www.smartergrowth.net/anx/index.cf m/3,176,673/metroinyourneighborhood.pdf Source: http://www.fairfaxcounty.gov/news/2010/board-approves-plan-transform-tysons.htm Flint, A. (2005). The Density Dillema: Appeal and Obstacles for Compact and Transit Oriented Development. Cambridge: Lincoln Institute of Land Policy Working Paper. McConnell, V., & Wiley, K. (2010). Infill Development: Perspectives and Evidence from Economics. Washington, D.C.: Resources for the Future. Mennis, J. (2003). Generating Surface Models of Population Using Dasymetric Mapping. The Professional Geographer , 31-42.

TOD and Housing 2000 - 2007

Transit Train and Metro Stations – Baltimore – Washington Region

½ mile buffer

Housing Increase 2000 – 2007

U.S. Department of the Interior U.S. Geological Survey Infill . Infill = Development that occurs on underutilized parcels in already urbanized areas

U.S. Department of the Interior U.S. Geological Survey Alternative Future – Urban Infill Example

. Prototype Area along the Baltimore – Philadelphia corridor. . In support of EPA Lyme Disease Risk Study looking at changes on the landscape and the affect on biodiversity. . To be expanded to the entire Chesapeake Bay Watershed Area.

U.S. Department of the Interior U.S. Geological Survey Purpose . Provide an example of a plausible alternative future scenario . Develop and execute a methodology for visualizing urban infill on a regional scale using widely available data . Find evidence of infill . Determine the affect of varying degrees of future urban infill on pollution loading

U.S. Department of the Interior U.S. Geological Survey Study Area

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

Measuring Infill . Determine the amount and location of vacant and developable land in urbanized areas . This process requires local data including tax map, , building permits, land valuation and other data at a parcel scale and generally involves a plot by plot analysis (Knapp & Moore, 2000) . Not practical on a regional scale due to limited data availability U.S. Department of the Interior U.S. Geological Survey Methodology . Develop an appropriate definition for Urbanized Area for a regional area . Using the Urbanized Area boundary determine the plausible spatial and temporal locations of historic infill by Census Block Group . Determine the rate of historic infill . Used as a guide to inform a trend scenario

U.S. Department of the Interior U.S. Geological Survey Defining the . Researchers have defined the urban area based on a set threshold of development intensity as well as density . Census Urban Areas are currently based soley on . Lack of standard definition for Urban Area

U.S. Department of the Interior U.S. Geological Survey Urban Area used for Residential Infill Analysis Analyzed the distribution of percentage developed 2010 block groups based on 2001 National Land Cover Dataset

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

U.S. Department of the Interior U.S. Geological Survey Analysis: . Expected Change = change in developed land expected due to housing change (2001 and 2006) . Observed Change = change in developed land observed from satellite (2001 and 2006) . Residential Infill = Significantly higher Expected Change relative to Observed Change

U.S. Department of the Interior U.S. Geological Survey Initial Findings / Results

U.S. Department of the Interior U.S. Geological Survey Infill Housing Change by County

What portion of total housing change in a county is located in residential infill areas?

U.S. Department of the Interior U.S. Geological Survey Infill Housing in Anne Arundel County 2001- 2006

11,851 Total Units Change

5,097 Infill Housing Change

43 percent of new housing is Infill

U.S. Department of the Interior U.S. Geological Survey What impact does varying degrees of Infill have on Water Quality?

Assumptions: . New growth (not infill) will be served by onsite septic systems . Lots are 1/4 acre and 1/3 impervious . Nitrogen pollution loading rates derived from the Chesapeake Bay Watershed Model

U.S. Department of the Interior U.S. Geological Survey Infill Scenarios – Nitrogen Loading TREND POPULATION (2006-2040) NITROGEN (lbs/year) Total 3,608,646 15,544,624 Infill 988,845 2,669,882 New Development 2,619,801 12,874,742 25% LESS INFILL Total 3,608,646 16,096,625 Infill 741,634 2,002,412 New Development 2,867,012 14,093,213 25% MORE INFILL Total 3,608,646 14,993,623 Infill 1,236,057 3,337,353 U.S. Department of the Interior U.S.New Geological Development Survey 2,372,591 11,656,270 Preliminary Conclusions . Land Cover alone is not adequate to determine the location and rate of urban infill development. . Why do we care? . Modeling future growth to assess water quality impacts requires us to get “infill” right.

U.S. Department of the Interior U.S. Geological Survey Additional Considerations . What about suburban infill, can these methods be applied in lower density, developed residential areas? . How can the results of this study be applied to developing alternative future growth scenarios? . Look more closely at proximity to transit and other areas with high amenities . Investigate additional demographic variables, such as marital status, empty nesters, or income.

U.S. Department of the Interior U.S. Geological Survey Contact Information Renee Thompson Geographer U.S. Geological Survey Chesapeake Bay Program Office [email protected] (410) 267-5749

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