Purpose and Need Statement

Purpose

The purpose of the project is to develop a safe and dependable water supply for the project service area that, together with existing supplies, will satisfy estimated water demands for a planning period of approximately 30 years, and that will reinforce water system’s reliability during periods of drought and other water emergencies. The proposed project will meet the water demands for the service area to the year 2040.

Needs

1. An adequate water supply is necessary to support continued growth of the service area. The service area for the proposed project includes the City of Raleigh and the Towns of Garner, Knightdale, Rolesville, Wake Forest, Wendell, and Zebulon, NC. The water and wastewater utilities for these six towns have been merged with the utilities for the City of Raleigh. The City of Raleigh also provides water to other communities in Wake County (Holly Springs and Fuquay-Varina) under existing sales contracts. The population projections for the service area are included in Table 1. The population projections are based on a review of projections for the municipalities in the service area from the Water Quality Study & Master Plan Update (WQMP) prepared by Hazen and Sawyer in February 2008, projections from the merger agreement development between the City of Raleigh and the merger municipalities, the merger agreement capacity allocations, and projections from municipal staff. The recommended population projections were primarily based on the WQMP, which used data for Traffic Analysis Zones (TAZs) from the Capital Area Metropolitan Planning Organization (CAMPO) 2030 Long-Range Transportation Plan. The TAZ data was used with future service area boundaries determined in consultation with City of Raleigh staff to arrive at future populations.
   
   
2. The water supply sources that currently provide drinking water for the project service area, including the communities served by sales contracts, encompass Falls Lake, Lake Benson/Lake Wheeler (scheduled to go on-line in
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   2010), and the Smith Creek Reservoir. The existing safe yield of the Smith Creek Reservoir is approximately 1 mgd, and the use of this source for water supply is currently planned to be discontinued. The existing 50-year safe yield of Falls Lake and Lake Benson/Lake Wheeler is approximately 78.4 mgd.
   
   
3. The projected water demand for the project service area for the Year 2040 is approximately 93 mgd. This projection includes allowances for sustainable reductions in water demand due to water conservation and reuse, which are important components of the City of Raleigh’s long-term water supply planning. On this basis, the proposed project, operated in conjunction with existing supplies as noted above, will meet the project service area demand through 2040.
   
   
   
   • The City’s water conservation program includes a program to educate consumers of the importance of water conservation, sets goals for reductions of water use on a day-to-day basis and during times of drought, and implements voluntary and mandatory water use restrictions in times of drought. Based on a review of the City of Raleigh’s recent experience with water conservation efforts, a reduction of at least 6 percent in historical average day water demands is sustainable, and has been used to estimate the impacts of water conservation.
     
     
   • The water reuse program is presented in the Reuse Water System Master Plan prepared for the City of Raleigh in January 2007. It includes recommended reuse water improvements to be implemented within a 30-year planning period. Potential customers for the reuse water system were identified by surveying potential customers, evaluating existing potable water irrigation use, and interviewing prospective customers. Total reuse water demands were then estimated based on the number of customers served by the recommended reuse water distribution system.
   
   The demand projections, including reductions in water demand associated with water conservation and reuse, are shown in Table 2. The total water demand projections, excluding conservation and reuse, are based on a review of water demand projections for the municipalities in the service area from the WQMP, the projections from the merger agreement development, and the merger agreement capacity allocations.
   
   
4. Based on the water demand projections for the project service area, summarized in Table 2, the City of Raleigh proposes to develop a water supply project that would have a 50-year safe yield of 14.6 mgd. This would result in a total 50-year safe yield of approximately 93 mgd, equal to the projected needs from the water demand studies for the 30-year planning period (2010-2040).
   
   
5. An additional water supply source will also increase the water system’s reliability during short-term or catastrophic interruptions in the system due to line break or equipment breakdowns.