Tampa Bay Water is reaching several significant milestones on a multiyear, multimillion-dollar program to develop, store, treat and transport new sources of potable water. A 66-million-gal-per-day surface water plant started production last month. After breaking ground in August, contractors are marshaling a large heavy equipment fleet to construct a 1,100-acre regional reservoir that will begin storing 15 billion gallons of water when complete in August 2004. A 25-mgd seawater desalination plant is near completion and is to begin production in November despite two bankruptcies on the design-build-operate team. To tie these components together and integrate them into the agency's existing system, contractors are placing some 70 miles of large-diameter transmission pipelines.
ACCESS Pipe work employs different placement methods, including a 40-ft-dia shaft for a tunnel boring machine. (Photo courtesy of Kenko Inc.)
Several interties and pump stations, a wellfield and a 9-mgd groundwater treatment plant round out 11 capital contracts currently under way. Totaling $609 million for design, construction and program management, the work comprises the first and largest phase of Tampa Bay Water's master plan, an ambitious three-stage effort to reduce the water wholesaler's groundwater extraction under permit from 192 mgd at the program's inception in 1998 to 90 mgd in 2008.
"We had to do something. We had over-permitted the system. We were extracting more groundwater than we could replenish," says Jerry Maxwell, the agency's executive director. Tampa Bay Water, which evolved from a regional agency established in 1974, is a wholesale water purveyor for Hillsborough, Pasco and Pinellas counties and the cities of Tampa, St. Petersburg and New Port Richey. The rate base includes about 2.1 million commercial and residential customers.
WATER CZAR Outsourcer Maxwell.
Maxwell calls the vectors that influence Gulf Coastal Florida's water policy "the four D's: drought, drainage, development and drawdown." The agency's power over the first three is minimal. "But we can attack the drawdown. We knew we could cut down on groundwater extraction, develop new sources of water further south, store it until we need it and be able to blend several sources to deliver a product that exceeds Safe Drinking Water Act standards," he says.
A steady rise in population is one factor making water politics as contentious in lush, subtropical Florida as in the arid West. Still, the agency's plans attracted scant public notice until a six-year drought pushed the issue onto front pages and television newscasts. "We normally average 52 to 54 inches of rain a year, but from 1988 to '94, we got numbers in the 30s and 40s," says Maxwell. Suddenly a host of interested parties took a keen interest in Tampa Bay Water's evolving game plan: developers, agricultural interests, the Florida Dept. of Environmental Protection, the South Florida Water Management District, the general public and even a 750-lb rogue alligator.
Maxwell credits the agency's board of directors for looking at the big picture. It consists of nine elected officials: two from each county and one from each city. "Pinellas County is built out--it has a density higher than Miami-Dade. It would be easy for them to balk at spending money to build a reservoir in Hillsborough or lay miles of pipe a long way from their user base," says Maxwell. Pasco and Hillsborough counties have large, rural tracts dedicated to citrus groves and cattle grazing. "In l996 and 1997 there was a huge policy shift. We suddenly had a board that could see beyond their own boundaries. They 'got it' when we started looking at a regional, watershed-based concept," he says. Click here to view map
Tampa Bay Water looked to the consulting engineering community to help formulate a master plan. "We are a lean agency. We had 108 employees at the time," says Maxwell, and 119 now. "We realized we needed outside expertise, and a lot of it, to get to where we wanted to go." Outsourcing also keeps down carrying costs for employee benefits, he adds. Funding the state retirement system costs 16 to 18%, versus a 6% match private companies carry on employee 401(k)s, he says.
The agency hired Kansas City-based Black & Veatch Corp. as program consultant. "We addressed the basic question: 'How can we make the system work hydraulically and maintain a higher water quality standard than the product we're replacing?'" says Helen O. Bennett, the vice president who heads B&V's Tampa Bay Water project work. "On top of that, we had to consider the schedule. That's a major driver." The owner brought on Jacobs Civil Inc., Pasadena, for program management support, with emphasis on scheduling.
A negotiated agreement with the Southwest Florida Water Management District tied funding to groundwater drawdown reductions. SWFWMD offered $183 million in state funds, contingent on the agency cutting groundwater extraction by 18%, to 158 mgd by 2004, and by 2008, to 90 mgd. For the reservoir and eight miles of large-diameter connector lines, the federal government has already committed $36 million toward the $134-million cost. The owner hopes to secure another $21 million before completion.
The agency is supporting the remainder of the funding, through bonds and rate hikes. When the master plan was put in place, the wholesale rate was 98� per 1,000 gallons, Maxwell says. It is now $1.75 and will be about $2 by 2004, when the first phase is completed. "Our rates are competitive with other purveyors in the Southeast," he says.
On the the same day Black & Veatch was hired in November 1998, Tampa Bay Water signed consultants to oversee all 11 projects. Design engineers, contractors and subcontractors soon followed. From the beginning, "We made the objectives very clear. This is an integrated, complex program. We have to reduce the groundwater 'take' and deliver 65 mgd of new water within the next four to six years," says Kenneth J. Herd, the agency's engineering and projects manager.
The scope of the job forced engineers to rethink strategy. "We had worked on systems consulting, but we decided to go after design work on individual projects," says Douglas W. Fredericks, Camp Dresser & McKee Inc.'s Tampa-based vice president. The bet paid off, as CDM won design work on the entire surface supply system, including two pump stations, connecting pipelines, an intertie and the water treatment plant itself.
The first challenge CDM faced was convincing US Filter Corp. to join forces to land the $96-million surface water treatment plant contract. "We knew their ballasted flocculation process was tailor-made for this job, but they had grown so big so fast that it took us a while to find the right people within their company to convince them that they had a winner," says Fredericks. Palm Desert, Calif.-based US Filter won the DBO contract, with a CDM plant design.
CDM coveted U.S. Filter's Actiflo process because it utilizes a much smaller footprint than a traditional plant. Ballasted flocculation is a two-step procedure that integrates ozone disinfection instead of more a conventional multi-stage system that requires large tanks for coagulation, flocculation, filtration, settling and disinfection. Actiflo uses two parallel process trains, where raw water is loaded with chemical coagulant. Microsand particles and polymer are added to the floc in the same tank. As fluid passes through eight filtration channels into a clearwell, sludge is removed for disposal. Sand is recirculated and clean water is disinfected.
"It's a great technique for treating high volumes of raw water in a small space, in a hurry," says Fredericks. "The loading ratio, compared to a conventional scheme, is 20:1." Plant design saves space through common wall construction, instead of a conventional campus-style layout. To add cost-effective capacity before the reservoir comes on line in mid-2004, Tampa Bay Water decided to increase plant yield by 10%, to 66 mgd. The $5.7-million change order is the project's largest to date. Overall, change orders have accounted for $13.1 million, or about 3% of $426 million worth of construction.
The owner favored a 15-year design-build-operate arrangement, with a five-year extension rider. "We like DBO. It shifts more money into the capital plant, but saves money in the long run by holding down operating costs. If you're driving the same car for 20 years, you want a Mercedes instead of a Hyundai," says Maxwell.
THE BIG POND. A 900-acre above-ground reservoir will supply the new surface water plant. An engineered embankment and access roads stretch its footprint to 1,100 acres. The earthen berm will average 55 ft in height, impounding up to 15 billion gallons of water. Omaha-based HDR Inc.'s design uses a bentonite soil cutoff wall varying in depth from 25 to 70 ft, with a geomembrane liner placed inside the berm from the top of the cutoff wall to the base of the crest road.
The owner spent more than two years on geotechnical work, says C. Edwin Copeland Jr., HDR vice president. Jeff Higgins, vice president and operations manager for prime contractor Barnard Construction Inc., says the extensive upfront information helped his firm put together a winning $86-million bid.
Bozeman, Mont.-based Barnard also tapped the local talent pool, hiring McDonald Construction Co., a Lakeland-based earthmoving contractor with phosphate mining experience. McDonald is providing much of the heavy equipment, 130 pieces in all, that will be needed to move some 12 million cu yd of earth. "In three or four weeks we'll start building the cutoff wall and then remove about 1 million cu yd of waste clay and replace it with competent soil," says Derek Tisdel, Barnard project manager. The workhorses will be Caterpillar 631 scrapers, which can push 18 to 20 cu yd of material, and "a lot of D-8s and D-9s and 740-ton trucks--nothing like the size you'll see in surface mining, but pretty big equipment," he adds.
VARIETY Contractors can choose iron, steel or concrete pipe. (Photo courtesy of Tampa Bay Water)
The contractor has allowed for some lost time to rain, but "usually we can knock off when the rain comes and then be back at it by mid-morning the next day, " Tisdel says. Embankment construction will move in tandem headings, starting at the center of the northern section and moving east and south and west and south. Wetland mitigation will proceed concurrently and pipeline work will start in about four months. Once the embankment work is well along, crews will construct an interior compacted soil cement liner, timing work to finish within a month or two of the containment wall.
Some 42,000 ft of 84-in.-dia steel pipe will connect the reservoir to its intertie. "Pipe used to be the most expensive way to provide water," says Copeland. "With development and environmental concerns shifting priorities, now it's one of the cheapest."
Some 70 miles of new transmission mains are tying together the new production, storage and treatment components. The project has been a boon to pipe vendors, who have supplied 33 miles of ductile iron, 36 miles of welded steel, 1 mile of prestressed concrete cylinder and a half-mile of fiberglass reinforced pipe, in diameters between 30 and 84 in. To increase competition, the owner specified ductile iron, steel or concrete, but let each contractor choose its preference. Tampa Bay Water buys the materials because it is exempt from Florida's sales tax. "We also carry all the insurance, because we can get a comprehensive rate cheaper than the contractors," says Maxwell. "Those measures save about $8 million."
Contractors are using five methods of pipe placement: pipe ramming, microtunneling, jack-and-bore, liner plate with hand-tool drilling and directional drilling. One of the most complicated segments, the Alafia River crossing, involves 900 ft of 96-in.-dia steel casing. To cross the river, Minneapolis-based Kenko Inc. constructed two secant pile shafts on either side of the river. An earth pressure balance tunnel boring machine cuts through soft limestone varying in compressive strength from 400 to 12,000 psi.
NO SALT. The 25-mgd desalination plant is also on time for a November start-up, despite initial opposition by environmentalists and bankruptcies on the DBO team. In many ways, the $108-million plant is the master plan's cornerstone (ENR 10/16/2000 p. 46). Touted as the largest capacity reverse osmosis desalination drinking water unit in the western hemisphere, the plant takes raw water from the cooling water intake at an adjacent Tampa Bay Electric Co. 1,800-Mw powerplant. The facility draws 15 Mw and produces water for about $2.02 per 1,000 gal. "It only makes sense to site this plant next to its power source," says Maxwell. "Reverse osmosis is power-intensive. The process is more efficient using warmer water from the plant's cooling water intake stream. Discharging the brine back into the plant's cooling water discharge stream, at a 1:70 ratio, minimizes the salinity load." Tides induce more of a change in salinity levels than the brine discharge, Maxwell says.
A carefully constructed 30-year DBO contract protected the agency against damage from bankruptcies on the team, first at Stone & Webster Corp. and then at Covanta Energy Corp. (ENR 4/15 p. 29). Maxwell credits project procurement manager R.W. Beck Inc., Seattle, with providing expert guidance.
"For us to negotiate on our own without good advice would be like going to bat against a major league pitcher and expecting not to strike out--next to impossible," he says. When Covanta went into Chapter 11, Tampa Bay Water exercised a buy-out option to isolate the project from bankruptcy proceedings. As a result, the job remains on course.
LATER, GATOR Crew removes rogue alligator from pipeline trench. (Photo courtesy of Kenko Inc.)
Other challenges are more mundane, but no less tangible. One morning, a pipeline worker encountered a 12-ft, 10-in. bull alligator. Workers wrapped the gator's jaws and eyes with tape, hoisted him out of the ditch in an improvised sling and had the state Fish and Wildlife Dept. remove the animal.
Tampa Bay Water now is turning toward configurations 2 and 3, which call for an additional 49 mgd of water by 2009. "Right now, we're trying to fine-tune our demand forecasting," says Herd. Plans call for additional wellfields and transmission mains, a 5-mgd brackish water reverse osmosis unit and another 25-mgd desalination plant. The trick is to balance demand growth, political support and available funding, Herd says.