2011-09-29 / Front Page

Panel discusses managing population growth


As part of the Jamestown Community Comprehensive Plan update, the Planning Commission discussed the build-out analysis of the town to determine whether the public facilities can meet the future town population at its Sept. 21 meeting.

A build-out analysis determines the maximum potential future population under current rules and regulations of a community and environmental conditions. According to the comprehensive plan, after the maximum population is calculated, the community can plan long-range goals and policies to protect natural resources and provide services and facilities.

In developing the build-out analysis, the Planning Commission considered that the average household size is 2.29 people, and an average of 15 percent of the land will be used for roads and infrastructure. The Planning Commission also determined that new residential developments will be single-family homes and accessory units where specifi ed. All of the units are year-round and have an accessed value of over $10,000.

In determining the potential new units in the town, the commission found there was a reduction from 1,133 to 733 in new units. The 733 units included 422 vacant lots, 106 developable sub-divided properties, 120 temporarily protected lots and 85 potential affordable housing. The 120 temporarily protected lots are qualified open space, which receive a reduced tax rate for not developing the land for 10 years.

The 2010 Census population results also demonstrate that the potential new population has decreased from 8,318 from the 2002 community plan to 7,077 for the total buildout population. The 2000 Census population was 5,622 and the 2010 Census population was 5,405. The potential new population for Jamestown, based on 2.29 people per household, is 1,679.

Town Planner Lisa Bryer explained that the number of new homes from 2000 to 2002 was 23 units, while in 2005 to 2007 there were about 20 new homes per year. In 2008 to 2009, there were between 18 and 19 new homes built. The av- erage over the 11 years is 22.7 new units per year.

In preparing the build-out analysis, the town must also consider the municipal sewer system. There are 1,213 current connections in town to the sewer system with 223 potential new connections, resulting in 1,436 total connections. The average daily use is 172 gallons per day per unit. The average daily inflow and infiltration is 150 gallons per day, for a total average daily flow of 390,000 gallons per day.

According to the plan, although the number of connections is reduced due to inflow and infiltration, the estimated hydraulic capacity of the sewer system – 2,267 connections – is still significantly greater than the maximum number of 1,436 sewer connections at build-out.

This disparity concerned Commissioner Michael Smith, who said, “It tells me our treatment facility can treat all the houses in Jamestown whether they’re in the system or not. The problem is getting the sewage to the facility. The problem in Jamestown is not its ability to treat water, but coming up with a source of water to treat.”

Smith suggested having the homes on private sewer and water systems, such as those that use wells in the north end of the island, come into the town’s municipal system.

Also, because of the conditions of the existing sewer pipes and groundwater infiltration, an additional 200,000 to 1.3 million gallons of water may enter the facility depending on the season. This reduces the maximum capacity of the sewage treatment plant. The ideal capacity of the sewer system is 4,244 connections and assuming no inflow and infi ltration, the number of connections at build-out is 1,436 connections.

The Planning Commission also discussed the number of potential new units per plat area.

“In all community districts, there is reduction in every zone,” Bryer said. “A lot of it is affordable housing, which will occur in the village area.”

Along the Jamestown Shores, plats 14, 15 and 16 have a reduction in potential units. In Plat 14, for instance, the number of existing units is 98, while the number of potential units is 37. The potential population increase is 85 based on 2.29 people per household.

In total, there are 2,721 existing units for all of the plats with 733 potential units. The potential population increase is 1,679.

Bryer stated that as part of the comprehensive plan, the town analyzes the number of potential facilities to determine if it can meet future town population as required by state law.

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