Marion, MA 2009 Buildout Report from the Buzzards Bay NEP
Click to read the complete Marion 2009 buildout report as a pdf file (includes all maps, 12.3 MB).
Build-Out Analysis for Marion, Massachusetts, Using Existing Zoning
prepared for the Marion 2015 Oversight Committee
John Rockwell, Regional Planner,
Buzzards Bay National Estuary Program
September 8, 2009
The Buzzards Bay National Estuary Program (BBNEP) provides technical and planning assistance to communities in the Buzzards Bay watershed on issues relating to surface water quality. Dense residential development has an adverse effect upon water quality by increasing the pollutant loads to water bodies via stormwater runoff. While stormwater best management practices (BMPs) can help reduce the pollutant loads from dense residential development, the BMPs cannot eliminate the increase in pollutant discharges. Large residential lot size results in less impervious surfaces, hence less impact to marine resources from storm water runoff. Larger lot size also brings new options for the preservation of open space through cluster zoning. Cluster zoning can also result in further reductions beyond that required for large lots and decreased pollutant loads.
The Town of Marion Planning Board requested the BBNEP perform a build-out analysis based on their existing zoning in 1999. In 2004, we updated this report based on a request was made by the Marion 2015 Committee, accounting for then existing zoning. This latest report was produced at the request of the 2015 Oversight Committee in April of 2009, again accounting for the latest zoning changes.
The amount of land in each residential zoning district is shown in Table 1: Residential Zoning Districts. For a look at the Marion Zoning, see map 1.
|Table 1. Residential Zoning Districts|
|Zoning District||Minimum Lot Size (acres)||Percent of Town|
|Residence A||0. 5||1.4%|
The BBNEP has compiled geographical information system (GIS) data for the municipalities within the Buzzards Bay watershed. The build-out was performed using recently updated Marion GIS files and assessor’s records.
The data used in the analysis is subject to error. While errors have been reduced by the updating of the parcel coverage, the GIS parcel data is not survey accurate. The parcel coverage used for this analysis is shown on map 2.
Starting with the parcel map, the BBNEP identified of types of land that would not be available for future residential development. Separate GIS layers were then constructed for each type of land ownership. All information regarding acreage is based on the BBNEP GIS data for Marion. These layers were:
All Roads (Map 3) – includes all areas designated as roads on Marion assessors’ maps. It does not include the old town roads (ancient ways) which are considered to be private easements by the BBNEP. This coverage does include all subdivision roads even if never constructed, but not those subdivision roads considered private easements, such as Deer Run and Pasture Lane. This coverage does not include an area of County Road that is actually in Wareham. Nor does it include a private subdivision road off of Point Road, for which no plan has been filed with the Plymouth County Registry of Deeds. (Total = 519 acres)
Permanently Protected Open Space (Map 4) – includes land in the Haskell Swamp Wildlife Management Area (owned by the Commonwealth of Massachusetts Department of Fish and Game), land owned by the Sippican Lands Trust, The Trustees of Reservations, the Town of Marion pursuant to several statutes, (M.G.L. Ch. 40, s. 8C – for conservation land, M.G.L. Ch. 40, s. 3 – for parks and recreation, M.G.L. Ch. 45, s. 14 – for playgrounds, M.G.L. Ch. 40, s. 41 and M.G.L. Ch. 40, s. 3 – for water supplies), and conservation restrictions held by the Town of Marion, Sippican Lands Trust, Wildlands Trust of Southeastern Massachusetts, The Trustees of Reservations and the USDA Commodity Credit Corporation. Also included is land subject to a Coastal Wetland Restriction pursuant to MGL Chapter 130, section 105. There is some overlap of the Coastal Wetland Restrictions with other Conservation Restrictions and land owned by the Town in Aucoot Cove. (Total = 3,262 acres) >
Town Infrastructure (Map 5) – includes those parcels held by the town for water distribution, sewer infrastructure (lagoons and pumping stations), transfer station, cemeteries, DPW barn, Town House, Sippican School, police and fire stations, and the Old Rochester Regional High School. (Total = 245 acres)
Utilities (Map 6) – includes electric transmission lines (on lots held by NStar), the telephone switching station, cable TV tower, and cable TV offices. (Total = 21 acres)
After creating and stripping away the protected areas in map 7, the remaining land (shown in map 8) can be considered as parcels available for new development or redevelopment. The BBNEP examined the parcels available for future development and redevelopment to determine the buildout potential of the lots. Factors considered to determine if the residential use of the lot could be intensified were:
1. the current use of the lot (Appendix A);
2. the size and location of the lot;
3. the applicable zoning district (map 1);
4. the velocity zone delineation (map 9) relative to the lot; and
To determine how much land was required for further subdivision of a parcel, each lot was considered to have no frontage. Therefore, to create an additional lot, the area containing the requisite number of square feet as required by the zoning district, as well as the area to construct a road to establish frontage was required. Since road construction can provide frontage for lots on both sides of the street, the area required for roads for each lot were:
Lot Frontage Required By Zoning (feet) X 50 feet (layout width) X 0.5
Stormwater controls are required in all subdivisions. To determine the amount of land dedicated to stormwater control, the BBNEP assumed soils in hydrologic class C, a pre-development condition of “good woods” and no storage available for rate or volume controls below a depth of three feet due to water table restrictions. Calculations regarding existing area requirements for frontage and stormwater controls were performed for the minimum lot size in each zoning district. The total land area for each lot was determined to be the following:
|General Business (GB)||18,120 square feet|
|Marine Business (MB)||18,120 square feet|
|Limited Industrial (LI)||18,120 square feet|
|Limited Business (LB)||17,508 square feet|
|Residence A (RA)||25,675 square feet|
|Residence B (RB)||48,558 square feet|
|Residence C (RC)||94,039 square feet|
|Residence D (RD)||95,315 square feet|
Since the Marion Zoning Bylaw allows an accessory apartment without a special permit in the LB district, each lot in the LB district was assumed to have a primary dwelling and an apartment at build-out.
Preliminary division of land into the eleven categories in the Information Compiled Regarding Residential Land Use in Marion, Massachusetts (Appendix A) was done to make a draft listing of the land that could not be further subdivided based on lot size, existing land use, and the applicable zoning district. There was debate in 1999 as to whether to include the town owned open space parcels that have no formal open space protection. To reflect the uncertainty of the status of these lots, a separate analysis was done in this report as well as in 2005 and 1999.
Many lots are too small to be developed (less than 5,000 square feet) or are unlikely to be developed due to lack of access for subdivision purposes, or wetland considerations. These lots were combined with the “Church Lots” (see Land Use Category 11 in “Appendix A: Information Compiled Regarding Residential Land Use in Marion, Massachusetts“) and no further analysis beyond an accurate inventory of those lots was needed. The preliminary information created regarding these three groups of lots is given below
Parcels not further Subdividable (Map 11) – comprising 2,277 acres, build-out at 3314 units. Many of these lots have existing structures. Includes Land Use Categories 1, 2, 4, 6 and 11. (See Appendix A)
Unprotected Town-owned Open Space (Map 12) – does not include salt marsh lots restricted by M.G.L. Chapter 130, section 105; comprises almost a half acre, build-out at 1 unit (Category 10; see explanation in Appendix A) .
When the layers above were created and removed from the parcels available for future development or redevelopment, there were 2,562 acres remaining o r 28% of the town (map 14). The area shown on map 14 represents the parcels that would be responsive to zoning changes relative to their effect on the residential build-out.
To determine the residential development potential of these parcels, which include both empty land and partially developed parcels, the effect of wetlands on the lots must be considered. Core wetlands (map 15) are mapped by the Department of Environmental Protection Wetland Conservancy Program (DEP-WCP). While wetlands may be included as a contribution for part of the minimum lot size requirements, the combination of the wetland exclusion requirements for residential properties and the mapping procedures of the Wetland Conservancy Program make it possible to exclude the DEP-WCP wetland area for the computation of lot size in the residential districts. The core wetlands in the residential district of the 2,562 acres account for 590 acres, leaving 1,972 acres, or 22% of the town, for further development. A table showing the distribution of the 1,972 acres by zoning district is provided below. (In commercial areas, Zoning Districts MB, GB, LI, and LB, there is no wetland exclusion and the wetland coverage was used to determine only if there was a minimum area (1,000 square feet).)
|Table 2. Areas Responsive to Zoning Changes for Reducing Built-Out|
Based on an analysis of wetlands and the velocity zone and specific subdivision decisions that limit further land division, the land areas investigated were placed into final categories as outlined in Appendix A. The BBNEP then conducted calculations of the number of existing dwelling units in each land use category (map 16) and the corresponding build-out potential. The final number of units at build-out is given below for each zoning district.
|Table 3. Build-Out results by Zoning District|
|Zoning District||Total # Potential Units||Projected Growth|
|Town Owned, Unprotected Open Space*||1*||1*|
* During the presentations of the 1999 build-out information, public comments were made regarding the assumptions of future use for the town owned, unprotected open space parcels, and the land owned by Tabor Academy. Build-out calculations are based on the existing zoning and what that zoning would allow in growth over time. For the purposes of this build-out report, no assumptions were made regarding the future intentions of landowners. However, based on questions and comments made regarding the 1999 report, the BBNEP has separated these two land owners from the rest of the town for informational purposes.
More detailed information for these calculations is available in Tables 4-6, where existing development and buildout potential is provided by land use category (1 through 11) and by zoning district.
Table 4: Existing Conditions indicates what the existing conditions are for residential land use in each land use category and zoning district. Based on the information available to the BBNEP the existing number of dwellings units is 2,971 (1).
|Table 4. Existing Conditions|
|Land Use Category||1||2||3||4||5||6||7||8||9||10||11|
Table 5: Growth by District again provides information by land use category and zoning district to show where growth may occur.
|Table 5. Growth By District|
|Land Use Category||1||2||3||4||5||6||7||8||9||10||11|
Table 6: Final Build-out provides information by land use category and zoning district for the build-out using the existing zoning provisions. Since the provisions for special permits regarding accessory apartments are fairly non-restrictive, a separate line has been added to show the effect of second units at each location.
|Table 6. Final Built-out|
|Land Use Category||1||2||3||4||5||6||7||8||9||10||11|
Sources and Accuracy:
The analysis was performed using a Geographical Information System (GIS). Known errors have been noted below. Overall, errors in data of + 2% should not be unexpected. Errors in the data can occur in three ways:
1. Land use characterizations were based on assessors’ data from Vision. Occupancy information and use codes sometimes conflicted. Discrepancies were resolved as best as possible using aerial photographs from MassGIS.
2. No GIS assessor mapping is survey accurate.
3. There may be restrictions on the subdivision and/or development of parcels not reflected in the Assessor’s Land Use Codes.