Safeguarding municipal water supplies at the source

Tackling the issue of watershed protection can be about as much fun as an IRS audit.

At the first hint of possible restrictions on land use, the turf-protection instinct of every interested party kicks in and the battle is joined.

Several jurisdictions with conflicting priorities may be part of the debate, since watersheds often cross political boundaries. And when the topic of money comes up, showing a clear link between watershed protection and cost savings can be tough.

Nevertheless, many local governments and water authorities are taking the plunge, motivated by public concern about water quality and federal actions like last year’s update of the Safe Drinking Water Act (SDWA) to better protect source waters. Although most managers would say their treatment processes are highly effective in meeting drinking water standards, limiting contaminants in raw water before it ever reaches the “end of the pipe” is getting more attention.

“Without a doubt, watershed protection is probably one of the issues that any water provider is dealing with on a daily basis, in one form or another,” says Peter Frost, executive director of the Douglasville-Douglas County (Ga.) Water and Sewer Authority (WSA). “It is becoming increasingly important. If you had talked about watershed protection 10 or 15 years ago, it probably wouldn’t have generated a lot of interest.”

It is a complex, contentious issue, but Jack Hoffbuhr, executive director of the American Water Works Association (AWWA), gets to the point nicely when he says, “It’s a lot cheaper to prevent pollution than to take it out later.”

Some municipalities, like New York City, do not currently filter their water supplies and are not eager to be forced to do so by Congress, so they are striving to better protect their drinking water at the source.

Many more, like Douglasville-Douglas County, which serves a population of around 75,000 residents 20 miles west of Atlanta, are already required to filter drinking water. Still, urban development in such communities and the accompanying non-point source pollutants are major potential threats to the quality of source waters.

These pollutants are the biggest watershed protection challenge for the WSA, which draws its raw water from reservoirs on the Dog River and Bear Creek, as well as from the Dog River itself. Although all of the land in the watersheds is privately owned, and around 90 percent is zoned for residential or commercial uses, it is still largely rural.

However, like much of metropolitan Atlanta, the region has grown, and so has the pressure for development in and around the watersheds. Frost and other officials have recognized the importance of protecting these lands, especially since the area has few other potential water sources — the Chattahoochee River flows along the county line, but, after passing through Atlanta, its water quality is so degraded that the state will not give WSA a withdrawal permit, according to Frost.

That is not to say the growth has been unwelcome. Frost’s argument is that a balance of development and source water protection is possible.

“What we’ve tried to sell to the public and elected officials is that we can have both growth and protection. I don’t think you necessarily have to give up one for the other,” he says.

The authority and city and county officials decided a zoning ordinance for any development in the watersheds should be a part of this balance. The ordinance requires:

• buffer setbacks from 100 to 300 feet along Bear Creek, the Dog River and their tributaries;

• no industrial, commercial or high-density residential development along these streams and no industrial development in the rest of the watersheds (projects existing or pending when the ordinance passed were not affected); and

• various minimum lot sizes, such as five acres for projects along the waterways and for high-density residential units in areas of the watersheds with no sanitary sewer.

Protection guidelines

The Douglasville-Douglas County WSA’s watershed protection program is one of 24 described in “Effective Watershed Management for Surface Water Supplies,” a study published in 1991 by the AWWA Research Foundation. The report aims to help water utilities and local governments develop their own effective programs and includes a national survey of water utilities and state regulatory agencies.

Survey respondents cite urban development and agriculture most frequently as the land uses that concerned them in terms of their impacts on watersheds. As far as dealing with these potential threats, the report finds watershed protection efforts as varied as the regions in which they were undertaken.

“There seems to be no uniform policy for watershed management,” says Richard Robbins, one of the study’s authors and a watershed hydrologist for the Portland (Ore.) Water Bureau — the city’s water utility. “It’s a battle being fought on the local level.”

Indeed, the local battleground may be most appropriate in many ways, given the differences that can exist from watershed to watershed and community to community. Because of these differences, the report concludes, source-protection plans should be as site-specific as possible.

Thus, the report recommends creating an inventory that characterizes the unique physical features, land uses, land ownership and water quality of the watershed as the first step in developing a program for source protection. Water authorities and local governments can then more effectively pursue the following steps:

• identifying contaminants of concern and the possible sources of these contaminants;

• establishing the goals of the watershed protection program;

• selecting control measures;

• implementing the program; and

• monitoring and evaluating the effectiveness of the program.

Karen Johnson, principal planner with Walnut Creek, Calif.-based Montgomery Watson, describes a similar process for developing a protection plan. However, she puts identifying stakeholders at the top of her list of basic steps. Planners can then proceed with:

• defining watershed problems;

• establishing goals and objectives. Johnson recommends focusing on specific problems such as microorganisms, rather than tackling every potential threat to water quality at once;

• assessing watershed conditions. Studying physical characteristics in the watershed such as soils and topography can help to define “vulnerability zones” (areas where source water is most threatened);

• identifying and evaluating management options; and

• developing recommendations and a plan for implementation.

Control measures are common elements of these approaches and can generally be defined as structural or non-structural. Structural controls are engineered solutions like detention basins and stormwater diversions, designed to intercept pollutants before they enter source waters.

When dense development in watershed areas makes structural controls necessary, the AWWA report finds that an integrated network of large, regional basins is considered more effective than smaller ponds. Smaller, development-scale basins may not be consistently maintained and dredged by the neighborhood associations often responsible for them.

Non-structural controls could be seen as taking watershed protection a bit further. They are intended to control land use in the watershed so that pollutants from sediment to sewage to pesticides are generated or released in reduced amounts, as opposed to intercepting such pollutants after they have been created.

Municipal acquisition of the entire watershed is perhaps the simplest and most complete non-structural solution. In Seattle, for example, the water department began buying land in its Cedar River watershed about 100 years ago. The utility now owns around 80 percent of the watershed and thus has a great deal of control over use of the land.

But most cities and counties did not get quite as early a start, and funds are not likely to be plentiful today for large acquisitions. It may be more realistic to pursue other non-structural measures like zoning restrictions on the density of development in the watershed, impervious surface limits, cluster development (whereby impervious areas are clustered in one portion of a tract, while the rest of the tract remains open) and rules for the siting, design, installation and maintenance of septic systems.

Depending on local circumstances, some of the following measures may also be part of an effective program for watershed protection:

• stream and reservoir buffers. Johnson urges planners to establish a sound technological basis for the size of required buffers;

• trespass controls and restrictions on reservoir use;

• written agreements with landowners. This step is more realistic when the number of property owners within the watershed is fairly small. According to Hoffbuhr, “If you don’t own the watershed, you’ve got to really spend some time with the owners to see if you can arrive at some agreement concerning acceptable and unacceptable practices;”

• encouragement of BMPs for land uses like agriculture and forestry in the watershed; and

• plan review (giving the water utility a place in local governments’ review process for land-use activities.)

Robbins argues that such non-structural measures can enable local governments and water authorities to take the greatest strides in protecting their watersheds. The measures can help to relieve some of the pressure that has built on water treatment processes to ensure adequate drinking water quality.

“The most important role for local governments is zoning the watershed in a manner that is protective of the water supply,” he says. “You can’t rely on filtration and disinfection alone.”

Nor can local governments rely on protection measures to take hold if all interested parties have not been involved from the start. Local utility managers and private consultants alike mention concepts like “stakeholder involvement” and “buy-in” as virtual commandments in planning to safeguard source waters.

The idea is to give all stakeholders from private landowners to environmental groups a voice in the process and ultimate solutions, with the goal of building community support for protection measures. Public meetings, newsletters and education programs on the basics of watershed protection are all vital parts of the mix.

As Johnson puts it, “The more that [citizens] understand, the more supportive they may be of restrictions on their activities. I’ve seen projects go down the tubes because the water purveyors just worked amongst themselves in working out the details.”

Robbins argues that water utilities should be leaders in public involvement and education. “The water utility really needs to be in the forefront and should not abdicate its role in developing a watershed management plan,” he says.

In Douglasville-Douglas County, the WSA has pushed for involvement and education and credits these efforts for much of its success in implementing land use controls.

“It’s not just putting something in the newspaper and hoping people read it,” Frost says. “We’re trying to reach them on every level.”

At one level is a monthly newsletter on issues of water quality which the WSA sends to customers in a mailing separate from bills. To educate future generations, the authority gives presentations in schools on water conservation and protection, hosts field trips and even sends school kids to water seminars.

“We have a very active relationship with the local school system,” Frost says. “It pays dividends like you wouldn’t believe.”

The shrewdest of direct marketers would likely be impressed by another WSA education effort, spurred by a local health department survey. The majority of the survey’s respondents said they were getting most of their health information from pharmacists, so the WSA prepared a water issues brochure that local pharmacists agreed to distribute.

The WSA is also making progress in watershed protection thanks to:

• state law that now allows the authority to enforce rules for septic tank maintenance;

• efforts by the county to address erosion from earth-disturbing activities, which Frost cites as the authority’s biggest challenge in protecting source water. The county has hired an inspector whose full-time job is to check development sites for proper silt-fencing; it has also changed its regulations to allow for stiffer fines and project shut-downs until erosion-control measures are in place.

In addition, citizens have volunteered to monitor streams and watch for potential threats like soil runoff. “It has helped us to have a lot of eyes out there that we wouldn’t normally have,” Frost says;

• watershed monitoring by the authority, including weekly collection of grab samples at 28 stream stations in the watersheds; and

• deliberate efforts to steer development away from the watershed by not extending sewer service to those areas. The authority instead focuses spending for new service in areas more appropriate for growth.

Watershed protection efforts like those in Douglas County will become even more important if federal regulations are further strengthened. Local suppliers may have a good opportunity to get started in the updated SDWA, which now requires the states to delineate and assess source water protection areas. A guidance document for meeting this requirement is expected from EPA later this year.

In complying with the act, states can set up voluntary, incentive-based programs for watershed protection in which local agencies can participate. Local partners will likely have access to maps and other data they could not tap into previously, according to Preston Luitweiler, chairman of the AWWA’s technical advisory committee for source protection.

So both the incentive and the resources (otherwise known as the stick and carrot) for local governments and water authorities to better protect surface water and groundwater sources seem likely to increase in the next few years. Pursuing effective measures now may lead, in the long run, both to improved drinking water quality and to better public perception of this quality.

Island gets water service

The Charleston, S.C., Commissioners of Public Works (CPW), the largest water supplier in the state, currently provides potable water to more than 450,000 residents in Charleston, North Charleston, West Ashley, plus Johns and James islands.

In 1995, the CPW had to look beyond the traditional cut-and-cover method of pipe installation to extend potable water service to a growing community on Daniel Island. The island was being developed for commercial and residential use, and a capacity of four million gallons a day was needed for an island population projected to reach 21,000 by 2015.

The island’s master zoning plan included a large number of public access points to the Wando and Cooper rivers, a variety of parks, a town center meant to attract corporate headquarters and fully-connected neighborhoods.

Traffic on the Cooper River was too heavy for the waterway to be shut down for digging to the island, according to Tony Maglione, director of design and construction for the CPW. In addition, the new pipe could have been pulled out of the riverbed during the frequent dredging of the river.

Finally, the cut-and-cover method would have put the pipe at the northern end of the island. The agency needed the shortest, most cost-effective route.

“The rapid growth of Charleston and the surrounding areas means we’re under pressure to complete larger jobs faster and with less money,” Maglione says.

The solution was to use directional drilling techniques to pull about one mile of 24-inch HDPE pipe 30 feet under the riverbed, reaching from the Charleston Peninsula to the southern tip of Daniel Island.

“Using HDPE pipe is the most economical option on long drill jobs such as this one,” Maglione says. “It’s tough and can be fused. This pipe will be under the riverbed, so we can’t have any leaks in the pipe or the joints.”

Houston-based Smit Land & Marine won the project with a $6.2 million bid, according to Maglione. The pipe, manufactured by Phillips Driscopipe, Richardson, Texas, and supplied by Fife Pipe’s Columbia, S.C., office, was heat-fused into a single, 5,200-foot stretch in a cornfield on Daniel Island. It was then sleeved in carbon steel for protection during the pull.

The contractor’s rig was positioned on the Charleston Peninsula and its drilling equipment, capable of 260 tons of pulling force, enabled it to drill under the Cooper River and pull the pipe through.

The contractor gradually enlarged the bore over three weeks from 3.5 inches in diameter to 42 inches, stabilizing it with bentonite pumped through the reamer. At its deepest point, the trench reached 87 feet below the ground.

The Daniel Island project was the first of three under the Smit Land & Marine contract. The contract included a second directional drill of almost 5,200 feet from Sullivan’s Island, southeast of the Charleston Peninsula, exiting into Charleston Harbor.

The final step was a standard cut-and-cover job, completed by Charleston-based subcontractor Parker Marine, in 10 to 20 feet of water along the James Island side of Charleston Harbor.

Videoconference scheduled

The League of Women Voters Education Fund is sponsoring a 90-minute interactive broadcast aimed at mobilizing local residents and their elected officials in drinking water protection efforts.

The program, Tools for Drinking Water Protection: A Community Call to Action, will be telecast on local Public Broadcasting Service stations March 19 at 2:30 p.m. It is designed to provide the practical planning and management tools necessary to create successful pollution prevention programs.

Participants will be able to question some of the country’s top drinking water experts via phone, fax and the Internet. Site facilitators will receive a guide with basic information about hosting downlink sites and suggestions for activities to accompany the videoconference.

The program will focus on both regulatory and non-regulatory tools. Topics will include:

• Making land-use decisions and identifying permitted and prohibited uses within designated areas;

• Organizing public education and awareness efforts;

• Creating monitoring programs;

• Involving a broad range of local entities in preparing contingency plans in case of contaminant release or other emergency; and

• Building leadership and securing funds for land use, education, monitoring and contingency planning.

For more information, contact the LWVEF at 1730 M St., N.W., Washington, D.C. 20036, (202) 429-1965. To register, call the PBS Adult Learning Satellite Service at (800) 257-2578 or visit the Internet at http://www.drinkingwater.org.

Slow sand filtration facility helps lower costs

Rutland, Vt.’s new 4.8 million-gpd slow sand water filtration facility is an example of simple, efficient and effective water treatment at a capital cost comparative to other technologies, but with significantly lower O&M costs.

The facility, serving Vermont’s second largest city, is entirely gravity driven and is only minimally reliant on electrical power. The plant, which went on-line in September 1995, has an estimated design life of 100 years and is built to withstand seismic forces.

The slow sand filtration process uses natural organisms in raw water to filter disease-causing organisms including Giardia cysts and Cryptosporidium oocysts.

The first slow sand filter in the country was installed in Poughkeepsie, N.Y., in 1872, and dozens of similar installations followed throughout the northeast.

During the early twentieth century, however, slow sand was overshadowed by rapid rate filtration technology, which could be used with a wider range of raw water quality and required significantly less space. By the 1950s, engineering textbooks referred to slow sand filtration only in a historical light.

Rutland took a fresh look at slow sand technology after passage of the Surface Water Treatment Rule. The city eventually based its decision to switch to a slow sand process, rather than to the rapid rate process recommended by two previous studies, on the projected low O&M costs and the proven longevity of slow sand systems.

Prior to design, the city emphasized the need for:

• a system driven by gravity;

• a facility that would be operable by a single person working a single shift; and

• low maintenance costs.

In 1993, after a one-year pilot study, locally based Wright Engineering began design of the new facility and eventually helped the city meet these goals.

The facility includes three filters, each 56 feet by 300 feet, with a total of 50,400 square feet (1.16 acres) of filter area. All filters operate entirely by gravity with a minimum of controls, and flow through the facility is continuous.

A 4,000-square-foot control building houses an office, a water quality laboratory and post-filtration chemical feed equipment (sodium hypochlorite, fluoride and zinc orthophosphate) and provides access to the filters and pipe gallery.

The city installed a finished water storage tank manufactured by Natgun, Wakefield, Mass., with a capacity of 2.5 million gallons — 50 percent less volume than that required for a conventional treatment facility, for a savings of over $500,000. A state waiver allowing less storage was obtained because of the simplicity of the design, the continuous operation and the reliability of gravity flow. Other highlights of the project include:

• no increase in city staff. The plant is staffed on a part-time basis during the day only, so that operators are free to attend to other responsibilities;

• maintenance of water rates below the state average, including debt associated with the facility;

• development of an emergency raw water intake in a separate watershed, including permanent piping to the filtration facility. In the event of watershed contamination, the city now has an alternative source to tap;

• the facility’s ability to operate on only a single phase, 400-amp electrical service. The only electricity needed during a power outage is to drive a small diaphragm pump feeding sodium hypochlorite; the rest of the process can operate without power; and

• simplicity of control. If the control system is out of order, the plant can be operated by manual valves.

The facility also has a SCADA system, supplied by LCS Controls, Rochester, Vt., for continuous data collection and reporting of facility operation and alarm functions.

Finally, the new filtration plant has enabled Rutland to meet its goal of reducing the use of chlorine in water treatment. Prior to construction of the facility, the city injected 2.5 to 3.0 ppm of chlorine into the distribution system to maintain adequate disinfection residual throughout the system. This led to ongoing complaints from customers, especially during summer months.

Now, however, the city adds less than 1 ppm of chlorine at the plant while maintaining the same distribution system residual. Rutland’s residents are better assured of a reliable, high-quality supply of water.