The Future of Impervious Surfaces on Cape Cod

legend percent imperviousness now vs. build out
Percent Impervious Surfaces per Land Cover Polygon - 1999 vs. after maximum build out

The Massachusetts buildout analysis predicts expected growth for each town in the Commonwealth based on current zoning and land use constraints. The results of the buildout analysis for Cape Cod were used in this study to estimate the potential increase in impervious area due to the expected population growth. The Massachusetts Executive Office of Environmental Affairs (EOEA) provided us with the buildout data for Cape Cod.

The polygons in the buildout data represent total likely ‘developable’ land. Unique attributes supplied with the data indicate the expected primary use of each potential development parcel. We assigned the attributes to the McConnell land use categories (See table below). Five separate polygon shapefiles were created including, Commercial, Industrial, Low Density Residential, Medium Density Residential, and High Density Residential. One exception to this rule occurred in the town of Falmouth. The quality of the buildout data for the town of Falmouth seemed to be lower and more complex than the rest of Cape Cod. To simplify, we omitted the extra primary use category.

Primary Code Description LU Code LU Translation
CP Conservation/Passive Recreation no data Omitted
GB General Business 15 Commercial
GI General Industrial 16 Industrial
HB Highway Business 15 Commercial
IN Institutional 15 Commercial
LB Limited Business 15 Commercial
LI Light Industrial 16 Industrial
ML Residential: 80,000 sq ft/ Agric. 13 Low Dens Res.
MM Residential:   5 - 15,000 sq ft 12 Med. Dens. Res.
NZ Not Zoned no data Omitted
OP Office Park 16 Industrial
R1 Residential: 80,000 sq ft/ Agric. 13 Low Dens Res.
R2 Residential: 40 - 80,000 sq ft 13 Low Dens Res.
R3 Residential: 15 - 40,000 sq ft 12 Med. Dens. Res.
R5 Residential:   5 - 15,000 sq ft 11 High Dens. Res.
RA Falmouth extra residential no data Omitted

 

A percent of imperviousness per land use polygon was created using an impervious surface coefficient per land cover class and updating the new land use category assignments for those areas within the developable land polygons.