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Feasibility and Site Selection Studies In April 2000, Tampa Bay Water's board of directors authorized PB Water, a division of Parsons Brinkerhoff Quade & Douglas to evaluate the feasibility of developing a second seawater desalination plant along the coast of the Gulf of Mexico in Pasco and/or Pinellas counties. The preliminary feasibility study evaluated 94 preliminary sites based on available information such as site size, available utilities, land use, zoning, ownership, and site development. The analysis, conducted for plants ranging from 10 to 25 million gallons per day (mgd), considered sites that met the following requirements that are essential to a desalination plant:
The study concluded that it would be environmentally and economically feasible to build a seawater desalination plant. The study identified several favorable project locations in Pinellas and Pasco counties, depending on plant size. Much of the coastline in the study area was ruled out in the feasibility study because it has already been developed. Other areas were eliminated because they were designated as ecologically sensitive. Still others were deemed too close to residential areas or too far from the Gulf. Eventually, the preliminary list was narrowed to the following 14 sites:
The study found that the drinking water distribution system in southern Pinellas County is limited to receiving about 10 mgd and that a larger capacity plant could be built in northern Pinellas or southern Pasco counties. Therefore, several sites from the preliminary list were subsequently eliminated (sites 11 through 14). Brownfields were also eliminated from further consideration, which removed sites 6 and 9. The study also estimated the costs of producing desalinated water and delivering it to Tampa Bay Water's transmission system. Preliminary calculations showed that costs to produce drinking water could range between $2.86 and $5.27 per thousand gallons depending on the site location and source water and concentrate discharge configuration. Costs escalated significantly the farther away the sites were from existing power and water sources and potential water delivery point(s). Therefore, sites 1, 2, 3, 5, 7, and 8 were not recommended for further analysis. Site 10 was considered less favorable and costly because it required piping water through a highly populated area. Following the preliminary screening process, researchers recommended a more detailed site-specific investigation of several locations in the Anclote River area Detailed Site Evaluation Between July 2001 and January 2002, Tampa Bay Water conducted a comprehensive detailed site evaluation study of 13 possible locations near the Anclote area from Tarpon Springs to Holiday. See Detailed Site Evaluation Study Area. The following technical criteria were used:
Public Input The team solicited and utilized public input in the evaluation of site criteria and, later, to rank the sites. In addition to meeting with various citizens, fishing, environmental and government groups, Tampa Bay Water mailed more than 11,700 newsletters with a questionnaire asking residents to provide input on site-selection criteria and their concerns about the plant's location. The newsletter also invited them to public meetings held in October 2001 to provide further input and discussion. When asked what benefits the plant would bring to the community, the majority of survey respondents and meeting attendees cited a new water supply and reduced dependence on groundwater as benefits. When asked about the special or unique qualities of the community that should be considered in siting a plant, most respondents mentioned marine resources, such as sponging, fishing and seagrass beds.
When asked to prioritize concerns in selecting a plant site, survey respondents cited the following:
Go to Public Input for the results of the October 2001 and January 2002 Surveys and Meeting Summaries. Public input played a significant role in the site selection process. For example, while environmental impact was already an important technical criterion, it received a higher weighting factor in the ranking process due to public concern. Also, in response to the public input, differential costs were added to the evaluation criteria. Differential costs are those that vary from site to site, such as the length of piping and pump size. The drinking water quality from the Gulf Coast Desalination will be very high and would be the same for each site under consideration. Therefore, noise and air pollution, odor, visual and aesthetics, and drinking water quality were not added to the list of evaluation criteria.
In January 2002, Tampa Bay Water presented a proposed detailed site ranking to the public through newsletters, news releases and subsequent stories in newspapers and on television. The proposed site ranking was presented in two public open houses on Jan. 29, 2002 and Jan. 30, 2002. In addition to offering verbal feedback, residents filled out forms, providing comment on the top-ranked sites. The agency also solicited input on the top-ranked sites through a survey that was mailed to more than 9,000 area residents and marine-oriented businesses. Some 156 survey responses were received by the end of January 2002. See Site Ranking Survey for details. The majority of the public considered Site A to be the most favorable. The second-most favorable site, according to public input, was Site C. Sites A and C were also the project team's first and second-ranked sites by the project team. Site Ranking In conducting the site evaluations, each site was given a score of 0 to 5 under each criterion. The criterion was assigned a weighting factor from 1 to 3 based on its level of importance from marginal to very important in the consideration of the site for a desalination facility. Each criterion score was multiplied by the criterion's respective weighting factor to compute a final weighted score. A matrix was created from the scores for each criterion, as shown in the Site Ranking Table. The weighting factors are described below:
The criterion and its level of importance are listed, as follows:
A site's total possible score was 100 points. Sites A and C ranked the highest with a total point value of 88 and 76, respectively. Sites B (75 points) and D (73 points) were the next most favorable locations.
All of the top-ranked sites can support near-shore or offshore intake of the source water and near-shore or offshore discharge of the concentrate. A brief description of the four, top-ranked follows.
Site A – On-site at the Anclote Power Station This site ranked #1. Power and seawater for intake and blending are readily available and it may be possible to share the power plant intake and discharge systems. This would significantly reduce costs. The site is cleared of vegetation and away from residential developments. Site C - North of the Power Substation (76 Points) This site ranked #2. This privately owned parcel is located on the east side of Baillies Bluff Road just north of the power substation across from the power plant. Approximately one-fourth of it is grazing land; the rest is heavily forested. The land would need to be rezoned from Residential to Industrial use. Site B - Across the Anclote Power Plant Discharge Canal (75 Points) This site ranked #3. It is northeast of the power plant, between the power plant canal system and Baillies Bluff Road. It is already zoned Heavy Industrial and its owner, Progress Energy (which was Florida Power), has indicated a willingness to negotiate. However, the size just meets the plant's minimum acreage requirement. Site D - South of the Power Substation (73 Points) This site is ranked #4. Located south of the power station on Baillies Bluff Road, this site is directly across the street from the Anclote Power Plant. There is a nearby residential neighborhood about one-fourth mile south of the parcel. Land use classification would have to be changed form Residential to Industrial. However, the site offers easy access from Baillies Bluff Road for construction and operation. Status After incorporating public input, the project team presented the final site ranking to Tampa Bay Water's board of directors. The board unanimously approved the site ranking for the proposed Gulf Coast project on Feb. 25, 2002. The agency is negotiating a lease contract with Progress Energy, the owner of the top-ranked site, and expects to finalize the agreement in early 2004. |
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This page was last modified: 4/28/2006 4:22:15 PM
