Making The Most of A Rainy Day
Localities are learning to capitalize on nature's own plumbing system.
The torrential rains that fell in Indianapolis on Labor Day might have devastated the city. A small stream called Pogues Run usually backs up where it flows into tunnels that carry it beneath city streets. That can send floodwater laden with mud, motor oil and sewage pouring into the heart of downtown--through the RCA Dome, Conseco Field House and the Indianapolis-Marion County government headquarters.
For decades, Indianapolis faced that risk every time it rained heavily. But this summer, the city finished building a $12 million project that channels the stream through 44 acres of parks and engineered wetlands upstream from downtown neighborhoods. When the 7.2-inch deluge hit on the holiday weekend, the basin's cattails and reeds soaked up 150 million gallons of runoff, filtered the pollutants out and then released the water slowly enough to flow gently into Pogues Run. "It worked exactly as it was intended to work," says John Oakley, the city's senior project engineer.
The outcome demonstrates what cities and counties hope to accomplish as they spend $40 billion a year--and quite possibly much more--to improve municipal sewage treatment, handle stormwater runoff safely and, at the same time, provide enough clean drinking water to growing populations. The task is becoming an expensive balancing act: Not only must local officials figure out how to dispose of water when it rains too hard, they're beginning to worry whether enough water will be available for people to drink the next time surfeit turns to deficit.
Just a year ago, in fact, much of the nation was suffering through an extended drought that threatened to dry up municipal drinking water reservoirs. This fall, in contrast, Midwestern thunderstorms and an East Coast hurricane caused damaging floods. Solving those problems will undoubtedly require heavy investments in steel and concrete and plastic pipes, along with treatment systems to remove contaminants from water supplies. But with improvements such as the Pogues Run basin, localities are learning they can spare themselves future water woes by making use of nature's own plumbing systems.
If they don't, warns former Maryland Governor Parris N. Glendening, "even as we spend some very serious money to correct existing problems, we'll be creating new problems" for the future. The way most communities and their water infrastructure are currently constructed "has actually reduced our water supplies in the long run and increased the fury of downstream flooding," he adds.
THE REPAIR BILL
The way things stand, state and local officials have their hands full just fixing a daunting backlog of decaying water infrastructure. Local communities have spent $1 trillion since the 1970s to comply with federal Clean Water Act and Safe Drinking Water Act standards. Even so, a number of studies by the federal government and water industry groups have made it clear that municipal systems that supply drinking water and remove wastewater are falling apart.
In some cities and counties, municipal utilities must extend service to growing populations living in newly built neighborhoods, even as they face a replacement problem: Underground pipes in some central cities are 200 years old. Some of the nation's oldest and largest cities are under court orders to replace antiquated combined sewers that funnel rainfall through the same pipes that carry household wastewater, discharging raw sewage when storms overwhelm treatment plant capacity. At the same time, federal regulators are cracking down on sanitary sewer overflows that also spill raw waste when rain seeps into cracked or rusting pipes that carry wastewater.
On the regulatory front, the pressure continues. U.S. Environmental Protection Agency regulations now require cities with populations of 50,000 or more to develop stormwater management plans so that "non- point" runoff from streets, parks and lawns will not transport motor oil, pesticides and other pollutants into nearby bodies of water. In addition, federal limits for 80 drinking water contaminants are getting more stringent. Even though virtually all the nation's sewage plants have installed secondary treatment systems for processing wastes, many bays, lakes and streams still don't meet water-quality standards.
EPA estimates that it will cost local governments $150 billion to improve pipes and disinfection plants for delivering drinking water and another $156 billion to correct sewage and stormwater deficiencies by 2020. Unless governments come up with those funds, EPA warned in a "gap analysis" study, "by 2016 pollution levels could be similar to levels observed in the mid-1970s." That would wipe out the hard-won gains of the past 30 years--gains that have markedly improved water quality. But as Trenton Mayor Douglas H. Palmer, who chairs the Urban Water Council for the U.S. Conference of Mayors, told Congress last year, "there is not enough local, state or federal money available to satisfy all the water infrastructure needs in the nation."
The council is backing congressional legislation to address the shortfall by reviving federal grants for hard-pressed communities, extending the duration of federal water infrastructure loans to 30 years and establishing new incentives for public-private partnerships between municipal agencies and private water and wastewater service companies. Under pressure from EPA and federal lawyers, big-city governments in the meantime have no choice but to forge ahead with some costly water-system improvements.
A MULTI-PRONGED PROJECT
Indianapolis is a case in point. It started building the Pogues Run basin in 1998. The project was part of a comprehensive $1 billion plan to both control stormwater runoff and stop the city's old combined sewers from overflowing during heavy rains, overwhelming wastewater- treatment capacity.
Even with the Pogues Run project on line, Indianapolis still released 350 million gallons of untreated wastewater during the Labor Day storm. Heavy runoff surged down street drains into a century-old combined system that flushes stormwater through the city's human sewage system. To fix the mess, Indianapolis is building a 3 million gallon storage tank and converting a concrete tunnel (built in 1915 to carry Pogues Run under downtown) to store stormwater surges. As part of the multi-faceted program to mitigate both combined sewer overflows and stormwater damage, the city plans on upgrading sewage-treatment capacity, separating some combined sewers and adding relief interceptor sewers. It will install an inflatable dam that can temporarily block heavy flows and lay pipes to divert other runoff to limestone mines beneath the city.
Two years ago, the city set up a Storm Water Utility funded by $1.25 monthly fees for each home, generating $10 million a year to improve drainage at 350 sites now prone to flooding. In consultations with nearby neighborhoods, city officials are offering to install park-like wetlands as alternatives to standard mechanical runoff control devices such as swirl concentrators and vortex separators.
Indianapolis also plans to spend $11 million on new management practices to prevent some of the polluted runoff from reaching the sewers in the first place. Those measures include doubling street sweeping efforts in nearby neighborhoods, stabilizing stream banks by planting vegetation and rehabilitating natural wetlands, forests and prairies within city limits so trees, grasses and soils can absorb instead of repel precipitation.
A HOLDING OPERATION
Some communities are starting to go even further to mimic the ways natural hydrological systems operate. Rain that falls on hard-surfaced rooftops or pavement rolls rapidly away, and engineers traditionally have designed stormwater systems and flood-control projects to straighten out meandering streams, line their banks with concrete and funnel surging waters through sewers and send it downstream as swiftly as possible. But some municipal officials are concluding that it makes more sense to redesign how neighborhoods are laid out so rain and snow soaks into soils or vegetation, then seeps slowly into groundwater aquifers as well as surface streams.
To deal with Philadelphia's sewage overflows, "we know we can build more BATs--big-ass tanks--and we can spend a lot of money and disrupt a lot of city parks," says Howard Neukrug, the city water department's watershed director. "But that would take the mistakes made 100 years ago and add to them." Instead, Philadelphia is spending $54 million to correct combined-sewer overflows, much of it on treatment improvements, inflatable dams and hydraulic gates. But Neukrug's office also is using state grants to promote innovative landscaping to keep precipitation from ever reaching sewer grates. In one project, the city installed 18 inches of gravel laced with drainage pipes capable of absorbing 45,000 gallons of rainwater into the ground.
Some major cities are encouraging developers and residents to put rain barrels under gutter downspouts, plant water-retaining "rain gardens," and landscape lawns and parking lots to hold precipitation on site and out of stormwater systems. Near Boston, the Charles River Watershed Association has been working with federal, state, and local officials since 1995 to monitor river conditions and identify pollution sources. The organization now has designed a "SmartStorm" device for retrofitting homes with backyard tanks that can store 400 gallons of rainwater from gutters and filter debris and contaminants. Some of the water will be used to water lawns; the rest will be released to infiltrate into the ground.
Portland, Oregon, has several similar efforts underway. Ten years ago, the Oregon Museum of Science and Industry redesigned the parking lot at its Portland building to filter runoff through vegetated swales. More recently, a new Portland State University student housing complex built in soil and vegetation planters to catch water from the roof; the water is then pumped inside to flush toilets.
"We're not experimenting anymore; these things actually work," says Tom Liptan, a Portland Environmental Services Bureau landscape planner. Still, Portland must spend $1 billion to correct problems in its existing sewer network, and Liptan acknowledges that "it hasn't been proven yet" that cities can save huge amounts in the long haul by substituting landscaping for infrastructure investments.
One study by American Forests, a conservation group, attempted to assign a value to what governments might save if natural systems absorb rainfall. The group calculated that the Philadelphia region will need to spend an additional $105 million to handle 53 million cubic feet of additional stormwater because development has intruded on Delaware River watershed forests, reducing their capacity to capture and hold on to that much precipitation. As Neukrug notes, "one gallon saved by keeping water on the land in the first place is one gallon less that you need to put in a tank, so that's some value to the city."
The Maryland-based Low Impact Development Center calculates that innovative designs can cut development costs 25 to 30 percent. That's because builders spend less money clearing trees, grading slopes, laying pipes and paving streets and parking lots.
The U.S. General Accounting Office reports that 36 states expect that some regions will experience water shortages in the next 10 years even if rainfall stays at normal patterns. Beyond drought problems, the fastest-growing urban complexes in the West and parts of the South are bumping up against water-supply limits. Tampa has begun desalinating seawater to fill the gap. San Diego plans to buy up farmers' irrigation rights as California is forced to cut back withdrawals from the Colorado River. Albuquerque is contesting court decisions that may divert its water allocations to support endangered minnows in the Rio Grande.
In Georgia, smaller cities worry that they'll lose their own future water resources to fast-growing Atlanta and its suburbs. As growth fills up the surrounding Chattahoochee River Basin, "Atlanta is going to start looking elsewhere for water," says Augusta Mayor Bob Young, co-chair of the Urban Water Council. Although Augusta now has surplus water from the Savannah River, "if our city evolves the way we want it to, we'll need that capacity," the mayor adds.
Those trends may set the stage for political and economic battles as population centers spread through dry regions. Even in areas that get much more rain, however, some communities are facing long-term water deficits. "My area of the country gets nearly 4 feet of rainfall a year, yet sections of eastern Massachusetts are literally running out of water," says Robert Zimmerman, the Charles River Watershed Association director.
The problem, he concludes, is "dewatering." The way cities have been built, he explains, is disrupting natural water cycles. At one time, rainfall soaked into forest and grassland soils and seeped into wetlands and groundwater aquifers that connect with surface streams and lakes. As more roads, parking lots, malls and homes are built, however, impervious surfaces repel the water; then conventional stormwater systems channel it straight into water bodies and release it to flow downstream.
The way municipal building codes and stormwater rules are written, "we send water someplace else and then wish we had it back when it's dry," says James M. Patchett, an Illinois-based stormwater consultant. "They're not written to get water back in the ground, and the cumulative effect is chronic problems in almost all of our watersheds."
In a study published last year, three environmental organizations-- American Rivers, the Natural Resources Defense Council and Smart Growth America--contended that sprawl compounds water-supply problems by keeping rain from recharging groundwater and surface reserves. According to their models, Atlanta's growth between 1982 and 1997 depleted local water supplies by as much as 132 billion gallons, enough to supply 3.6 million people for a year. Boston may have lost 102 billion gallons, and Dallas 14 billion. Maryland's Glendening, a champion of smart-growth policies, concludes that "if sprawl and impervious paving continues, the next drought will be significantly more severe."
To prevent future shortages, governments will be looking at how to tap brackish water and import water from other regions. But some public officials think communities also need to make better use of the water that, quite literally, falls on their own backyards. "The big- pipe solutions will cost hundreds of billions of dollars, and investing in technologies that reconnect rainwater to groundwater might save the U.S. tremendous amounts of money," Zimmerman says.
The way the federal Clean Water Act and Safe Drinking Water Act are set up, state and local governments now handle stormwater flooding, sewer overflows, and water supply issues through separate regulatory programs. But in the natural world, Zimmerman points out, "there are connections between stormwater and rainwater and groundwater and recharge to rivers. If you could re-create the way it used to work, a lot of problems would go away."
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