Build out analysis within the Pleasant Bay Marine Water Recharge Area

 

Summary

 

The Pleasant Bay Alliance has developed a build out analysis to determine the potential for new residential development within the marine water recharge area (watershed) of Pleasant Bay.

 

The analysis shows that 1,728 new dwellings could be added throughout the watershed on developable lots, an increase of 28%.  Nine of the Bay’s twenty-one subwatersheds could see an increase in new dwellings of 40% or more.  

 

The Alliance will continue to evaluate the implications of the build out analysis within each subembayment, and to determine if there are any specific actions that could be recommended to the towns to enhance protection of the Bay’s resources.

 

Research Objective

 

The Pleasant Bay watershed, shown on the attached map, consists of 21,306 acres.  Acreage within the watershed is divided among the towns of Orleans (43%), Chatham (31.5%), Harwich (12%), and Brewster (13.5%).  The watershed feeds surface and groundwater into Pleasant Bay and its tributaries.  Groundwater discharge and overland run-off from land uses within the watershed are critical factors in determining Pleasant Bay’s water quality.     

 

The Towns of Orleans, Chatham, Harwich and Brewster have recognized the value of Pleasant Bay to the region and the need to work together to ensure that Pleasant Bay remains healthy and enjoyable for future generations.   The towns developed a resource management plan (RMP) for the Bay and its watershed, and three of the towns formed the Pleasant Bay Resource Management Alliance to implement the RMP. 

 

The RMP includes a number of recommendations dealing with watershed planning and management.  Three direct examples are:

 

Ø      Development of a watershed management program encompassing nitrogen management, storm water management, fertilizer and pesticide use, and public education (recommendation 9.4.1);

Ø      Evaluation of the need for changes in land use regulations (recommendation 9.4.2); and

Ø      Strengthening specific provisions of local wetland protection regulations and review procedures (recommendation 9.6.1).

 

 

 

The Alliance found that a comprehensive assessment of future development potential within each subembayment of the Pleasant Bay watershed was needed to evaluate specific actions the towns could take to implement the watershed protection recommendations cited above.  The Alliance also recognized that any such actions would be intended to reinforce the local comprehensive plans and wastewater management plans being developed within the towns.

 

Methodology

 

The build out analysis was developed with technical support from the Cape Cod Commission GIS Department.  The analysis is based on the most current parcel data available from each town’s assessor’s records.  The development status of each parcel was determined by evaluating:

 

State land use classification code:  Classifications codes were used to distinguish the status of parcels (e.g., residential development, vacant land, protected open space, etc.) 

 

Current development status:  Parcels were evaluated to determine if they contained a dwelling or not.  A parcel was further evaluated if it did not have a dwelling, or could accommodate additional lots through subdivision. 

 

Existing applicable zoning:  Potential development was determined based on the existing applicable zoning designation for the parcel.

 

Existence of wetlands:  The area of wetlands on a parcel, if any, was subtracted from the potential area for development to which the zoning requirement was applied.

 

For example, a developed single-family parcel is considered an existing lot.  Potential additional lots are of two types.  (1) A vacant parcel able to accommodate a single-family lot is counted as one potential additional lot; (2) An existing parcel with a dwelling(s) built on it, but with potential for subdivision, is counted as the number of potential additional lots that could be subdivided under current zoning, adjusted for the presence of any wetlands.

 

This analysis does not include expansion of residential dwellings through redevelopment of currently developed parcels.

 

Key Findings

 

The findings from the build out analysis are summarized in the attached matrix.  Highlights include:

 

Ø      There are 6,100 existing lots in the watershed and there is potential for an additional 1,728 lots, or a 28% increase.  Of the additional 1,728 lots, 679 (39%) are in Orleans, 526 (31%) are in Harwich, 315 (18%) are in Chatham, and 208 (12%) are in Brewster.  

 

Ø      The following subwatersheds could see an increase of 40% or more in developable lots: 

 

Arey’s Pond (Orleans, Brewster); Namequoit River (Orleans, Brewster), Quanset Pond (Orleans, Brewster); Little Pleasant Bay (Orleans); Pochet Neck (Orleans), The River (Orleans); Kescayogansett Pond (Orleans); Pah Wah Pond (Orleans); Bassing Harbor (Chatham).

 

Ø      The following subwatersheds could see the largest numeric increases in developable lots:

 

Arey’s Pond (121); Namequoit River (203); Pleasant Bay (460); Round Cove (84); Upper Pochet Neck (89); The River (68); Frost Fish Creek (81); and Muddy Creek (343).

 

Ø      Evidence of excessive nitrogen has already been found in waters surrounded by watersheds with significant additional build out potential:  Muddy Creek, Arey’s Pond, Meetinghouse Pond, Round Cove, Lonnie’s Pond, Quanset Pond, Pah Wah Pond, Pochet, Crow’s Pond, Frost Fish Creek, and portions of Big and Little Pleasant Bay.  This water quality data has been gathered through the Alliance water quality monitoring program, and the Chatham and Orleans wastewater plan processes.

 

Ø      785 or 45% of potential new lots are located within a Zone Two, which is an area identified as contributing to public drinking water supplies

 

Next Steps

 

The Alliance will continue to examine the implications from the development potential within each subembayment.  The Alliance will also continue the collection of comprehensive water quality data throughout the Bay and its subembayments.  This information will be used to evaluate various land use, wastewater management, or wetland protection measures that could be recommended to the towns to enhance protection of marine water quality, wetlands, and habitats within the Pleasant Bay area.