St. Petersburg — Anticipated shortfalls are uppermost in the minds of many water officials across the nation. While most are scratching their heads wondering what to do, one unruffled Water Utilities Manager is not shy about explaining how trenchless technologies, polyethylene pipe and a well orchestrated plan will not only conserve water, but save his city untold millions.
Joe Towry, the Manager of the Water Systems Maintenance Division for the City of St. Petersburg Florida is at present in the process of implementing an 18-year $100 million program to replace and upgrade the city’s aging water system infrastructure. His mission is the result of several years of research with attention focused on the future of St. Pete’s water system.
Towry has taken a methodical approach to the project and uses his background as an analyst to better dissect and understand the city’s infrastructure.
To compare HDPE with other materials solely on price per linear foot is not a proper comparison
“It makes more sense to have an organized plan than it does to spend all of your time chasing and putting out fires,” says Towry. He proudly points to a map of the city hanging in his office on an easel as if it were a work of art. The multi color-coded map displays detailed information including the age of the infrastructure in each neighborhood along with projected cost for replacement and linear foot descriptions. A quick scan places the totals of pipe in the range of 3 million linear feet. Pipe in the target areas ranges from 2 inch to 12 inch in size. He points to a red area on the map and says, “Some of the pipe in this area is over a 100 years old, but in the overall scheme of things, it’s not necessarily the highest priority area requiring immediate attention. Some of it is actually performing quite beautifully.” He slides his finger to another portion of the map like some General in a war movie and says, “Here is where we have the more prevalent concern and need.”
Towry has systematically gathered information through his citywide Leak Management Program for each quadrant of the city. He knows exactly how many times his repair crews have been in each neighborhood to fix leaks and concentrates on replacing the pipe in the problem areas. “Once I determined where our greatest problems existed, it was easy to prioritize the long and short term replacement and construction phases of the 18 year program.”
The overall leak rate for the city’s entire system is currently 6.5% (well below the national average.)
St. Petersburg has a history of being farsighted. The city is home to the nations first urban reclaimed water project and citizens who participate in the program have the ability to irrigate their landscape, without restriction, most of the year. Other uses include, cooling tower make-up water, fire suppression, air scrubbers, machine cooling and other industrial applications.
The reclaimed water project is a big part of the water conservation efforts in St. Pete but number one on Towry’s list is the preservation of the drinking water system. This goal is imperative to the city’s future and one of the tools that is playing a significant role in protecting every drop, is High Density Polyethylene (HDPE).
HDPE was first developed in the late 1960’s for the gas industry because of its leak proof qualities. Today 90% of all new underground gas lines installed are HDPE. According to 1999 Gas Facts there are 380,000 miles of HDPE main gas lines and 28 million service lines in the U.S. Of these, there is an average of fewer than 10 leaks a year caused by something other than third party damage.
While incremental improvements to the nations water distribution systems have been made over the last 100 years, many like Towry feel it is time to aggressively implement the latest technologies like trenchless construction and HDPE to the water industry. St. Pete is aggressively applying this technology in three activities within the utility beginning with the potable water system, reclaimed water system and the wastewater collection system.
For instance, it is commonly believed that a leak rate of 10 to 15% is a normal acceptable level. Times have changed since the first half of the twentieth century, when populations were smaller, labor was cheaper, and water was relatively plentiful. City officials like Towry are now directed more towards conservation, cost, and safety. As such, governmental regulatory agencies, and conservationists are reviewing water distribution systems and paying heavy attention to leak management; and, they are finding the costs staggering.
According to the Community Water System Survey, water utilities self reported leak rates average 13%. One study by the International Water Supply Association states that 20 to 30% of water never reaches its intended destination. Whichever number one believes, the effects of such high leakage are taking their toll.
For example in 2002, the governor of New Jersey declared a Water State of Emergency; Dallas reported a 26 billion gallon infrastructure water loss; Colorado experienced the worst drought in the history of the state; and, Atlanta issued boil water advisories for the areas of its city that have the worst infiltration problems.
While the problems are commonly blamed on drought, the state of New Jersey announced that their water distribution system has a leak rate of 25%. It is doubtful the problem would be as severe, if their system did not leak.
To put this into a different perspective, consider the US water distribution system in the aggregate. There are 54,000 water systems in the US processing nearly 34 billion gallons of water per day. A 25% loss is equivalent to 8.4 billion gallons of water produced, but never delivered. To have a better understanding of the amount of water involved, consider that about 6.9 billion gallons of water passes over Niagara Falls every day. Even using the consensus on acceptable levels of leakage, there is almost as much water leaking from our piping systems on a daily basis, as the amount that pours over Niagara Falls each day.
It is certain that a percentage of the water loss is due to fires and flushing water lines. However, the majority of the water loss comes from worn, broken pipes and joints caused by corrosion, aging, ground shift and loading (water hammer).
The high cost of premature replacement or repair of failed or leaking pipe systems has a big impact on the economics of distribution systems. More than 25% of publicly owned systems serving up to 50,000 connections reported economic losses.
U.S. Community Water Systems reported a capital investment of $32.6 billion from 1993 through 2000. Of that amount, 30.6% was spent on repair and replacement of failing pipelines instead of much needed new infrastructure.
The city of St. Petersburg is protecting the future of their water distribution system by replacing their lines with PE wherever it is economically possible. PE has a reliable service life of more than 100 years and is impervious to almost all of the problems that plague pipelines across the nation.
“To compare HDPE with other materials solely on price per linear foot is not a proper comparison,” says Towry. “Other items should be taken into consideration like the long-term investment. Leaks are expensive, if I can spend an extra three dollars today that will save the city $100 in the future, I have done my job well.”
Perhaps the strongest advantage of PE is how it is joined together. The pipe is heat fused together creating a joint that is stronger than the pipe itself. With no joints, the pipeline becomes a true monolithic structure that has no weak link. The life cycle of the system is then based on the material and not the connecting points. The only chance for leakage comes from third party damage.
Towry’s crew uses McElroy fusion equipment to heat fuse the pipe. McElroy has been designing fusion equipment for over thirty years and has distributor locations worldwide.
“McElroy fusion equipment is the toughest on the market,” said Frank Lopez HDPE Product Specialist of Hughes Supply, a McElroy distributor based in Tampa Bay. “The training is relatively simple and most fusion technicians can become proficient in a short amount of time.”
Lopez has been instrumental in advising Towry in the technical use of HDPE. As an expert in HDPE applications, Lopez and other Specialists write specifications for municipalities and engineers with an eye toward getting HDPE incorporated into projects. He has been the point man on all HDPE projects and supplied the pipe as well as the training on fusion equipment for the city. “The city of St. Pete is ahead of the curve when it comes to water infrastructure,” said Lopez. “They are looking into the future and designing a system that will withstand the test of time.”
Towry explained there is a considerable laundry list of concerns associated with residential neighborhood pipeline construction. Many of the areas in St. Pete have been classified as historical preservation areas with brick streets, granite curbing and hex block sidewalks. Removal and restoration of these assets using conventional open cut construction techniques within historical areas, comes with a considerable price tag. Adding to the costs formula are; million plus dollar homes, expensive landscape, well manicured lawns and designer driveways; this is where Towry uses trenchless technology to his advantage. Thus reducing the number of concerns from area residents and area homeowner associations.
“Everywhere it is feasible, we use HDD procedures,” said Towry. “Not only is it the least intrusive, it is the most economical.” HDD techniques provide little disturbance to streets or sidewalks and eliminates much of the expense of replacing asphalt.
HDD is performed by drilling a hole down for a distance and then horizontally for however far the pipeline needs to travel. Polyethylene pipe is then pulled into the hole.
“PE is tough enough and flexible enough to withstand the stresses placed on it during the pull back,” said Towry.
St. Petersburg owns two directional boring machines. The smaller machine is used to install 2-inch water lines and service lines, Â¾ inch through 4 inch. The second machine is designed to install 2 inch through 12-inch water mains and has been used to pull short runs of 16-inch pipe. The two machines give the Water Systems Maintenance Division greater flexibility and more opportunity to deal with sensitive issues, unusual and sometimes complex problems, in a timely fashion.
To ensure effective use and operation of the equipment, specialized teams have been developed within the ranks to deal with the new technology. The vision for the future suggests that with the addition of new equipment, more teams will be developed from within to increase productivity, efficiency, maintain costs and accelerate the replacement schedule of the long term program.