“Who would build a wastewater treatment plant and not operate it, and just let it go?” asks Tom Schueler, executive director of Chesapeake Stormwater Network (CSN). Although it sounds like a rhetorical question, Schueler clarifies its importance. “Basically, we have installed hundreds of thousands of stormwater best management practices across the Chesapeake Bay watershed; they are explicitly designed to trap sediments and capture pollutants, and they require ongoing maintenance to keep them operating as they were originally designed.” Yet, he says, for many stormwater BMPs there is the quandary of who will take on that task of long-term maintenance.
“The fundamental problem is that most stormwater BMPs are triggered by new land development, so we can find a person, in the form of a developer, to pay for their initial construction, but once the developer leaves the scene and homeowners or business owners inherit the stormwater practices, they have no idea what they are and they have no budget to maintain them,” he says. “It’s an issue that has been fraught with problems.”
Nevertheless, he says many of his colleagues believe that maintenance is one of the most important tasks in stormwater management. “We surveyed 10,000 members of our network, and they agreed that stormwater maintenance was the most critical aspect of BMP performance, and that improving maintenance would be more effective than achieving newer levels of design or better construction.”
Schueler, who previously helped establish the Center for Watershed Protection and had a hand in many of the stormwater design manuals used in the Chesapeake Bay region and around the country, may be right when he points out that exactly nobody tells their mom, “I want to be a BMP maintainer when I grow up.” He notes, “There’s very little glory in it, but it is essential to the performance to prevent flooding and keep the pollutants from entering local streams from the Chesapeake Bay. In our profession there is a lot of glory that goes to design and research on improving performance, but there has never been a great deal of work on inspection and maintenance. That’s one of the things we’ve focused on at the CSN.”
BMP Illustrated Manuals
Communities that have MS4 permits have to inspect their entire inventory of legacy BMPs in the Chesapeake Bay watershed, Schueler says. That includes all stormwater practices that were built since stormwater regulations were imposed since the 1970s and 1980s. Communities like Montgomery County, MD, might have somewhere between 10,000 and 15,000 practices to inspect every three to five years.
To make this daunting task more manageable, Schueler says, “What we’ve focused on is how to use technology and how we can identify visual indicators that field crews can use to quickly assess, in a triage-like manner, the condition of a particular BMP and come up with a quick punch list of needed maintenance tasks to restore its function and move on to the next one.”
With Ted Scott of Stormwater Maintenance & Consulting, Schueler developed a manual called Bioretention Illustrated, which featured a series of photographs showing operating and failing bioretention areas. “It was very useful in training a new generation of inspectors in what was working and what was not working and how it needed to be corrected. It also provided numeric triggers for when something was bad enough to require immediate maintenance.”
That publication has been very popular, Schueler says, garnering close to 5,000 downloads. Encouraged by Bioretention Illustrated’s acceptance, CSN has extended similar analyses to other low impact development (LID) practices such as infiltration, permeable pavement, and bioswales, compiling informative manuals of indicators and maintenance procedures for a widening range of practices that are accredited under the Chesapeake Bay total maximum daily load (TMDL). He hopes to add to the bookshelf in the near future with manuals on “things like stream restoration, with indicators that can be used to verify that the practices that are installed for pollutant reduction credit under the TMDL are actually working.”
Schueler says the whole notion of how to inspect and maintain stormwater practices is a national concern that local governments are facing, as evidenced by the increasing focus on the topic by professionals. For example, he says the American Society of Civil Engineers (ASCE) now has an annual stormwater manual conference. He says there are now resources to help prepare landscape professionals for these tasks. One such resource, developed by Beth Ginter, is the Chesapeake Bay Landscape Professional Certification program. It offers training to landscaping contractors, a population of 50,000, in the essentials of stormwater maintenance and certifies professionals who have received that training so that local governments and even homeowner associations can know whom to hire.
Staying Healthy With Checkups
Schueler compares stormwater system maintenance tasks to “daily brushing and then the occasional root canal.” He explains, “The daily brushing is going out to a bioretention area and picking up the trash, making sure the inlets are unobstructed, and relieving clogging. That’s done on a quarterly basis or semi annual basis and is often done by landscaping contractors.”
He continues, “When you have non-routine maintenance, the stuff that would be the root canal, that usually requires engineering and some kind of forensic investigation to figure out what’s really gone wrong with the practice, and it can be very expensive, anywhere from $20,000 to $250,000 to correct something of that magnitude.”
To cite examples, he says that for a pond, a situation could occur where “over the years the pipes going through an embankment have corroded and need to be replaced, otherwise the embankment will fail. That fix is a major re-piping and re-plumbing of the facility.” As another example of a serious problem, he cites the scenario of “an old dry pond that never got mowed, so it’s all grown up in trees and they have to bush-hog it and restore its original condition, or it’s completely filled up with sediment and the sediment needs to be removed.” With bioretention, he says, the major issues are “usually a problem with the underdrain, or clogging, where the water can’t leave the facility, so they need to essentially rebuild or do a big makeover of the facility to restore its function.” However, Schueler says that these problems are not very common. “They may be 5 or 10% of the practices, but they’re big-ticket items, and they take some assessment to figure out what’s really going wrong.” Nonetheless, he says, “They are obviously unexpected to the owner and fairly expensive to redo.”
He adds, “We put a lot of money into building the practices, but in many areas the practices can fill up and gradually lose their function because they are not maintained.” He says one of the keys is training.
Schueler recalls a workshop with state employees in Pennsylvania who were going to do some inspections. “They all remarked that while they were hired as stormwater inspectors, they had no previous training in how to conduct an inspection. It had always been kind of like a Jedi warrior thing where somebody would say, ‘Oh, yeah, this is what you do.’ That’s why we work so hard here at CSN to work with experts to try develop more structure in training and outreach that people can use to do a good job at inspecting. We’ve done that for ponds and all sorts of things.”
Schueler is optimistic about the prospects of getting personnel trained to perform stormwater BMP inspections. “Generally, they can be trained with two days in the classroom and one or two days in the field. Sometimes it’s a person-to-person training. It doesn’t take a four-year degree.”
Under the Rambling Road
Hot Springs Village, AR, was at one point the largest gated community in the US. The main road through town winds 14.5 miles from the west gate to the east gate, and nearly all the other roads accessing homes and businesses in the community feed off of that, says Jim King, vice president of Krapff Reynolds Construction, a construction contracting firm in the region. It’s not a lonely road, he says. “It is monitored at each end with a guard house where they check every individual coming in.” There are others that work on the road as well. “They have a crew that maintains the road, that goes out in the summer to do mowing and tree trimming” along the thoroughfare. In the winter, when that work slows down, they become the maintenance crew for other local infrastructure in connection with the road.
“They go out and they survey roads and sidewalks and storm drains,” says Tyler King, superintendent for Krapff Reynolds Construction (no relation to Jim King). Recently, he says, these road crews “found a lot of stormwater pipes that had collapsed or were half-full with debris and a bunch of pipe that was rusted and rotted out.”
A visual inspection of all of the stormwater conduits serving DeSoto Boulevard, the main road through town, confirmed the same was true for “pretty much all of the lines,” says Jim King. Corrugated steel pipe, in 60-foot runs, were intended to connect storm drainage ditches across the winding road as it zig-zagged through the town, but Tyler King points out that the road had experienced washouts in a few places because of the decaying 30- to 48-inch-diameter pipes. According to Jim King, local officials were also concerned that if a major washout were to occur on the road, it could be catastrophic for the community, because DeSoto Road is the main access to the village.
In addition, Jim King says town officials had plans to begin resurfacing the road with new asphalt in the coming year and felt that it made sense to rehab the underlying infrastructure before making that investment.
In evaluating how to address the failing stormwater conveyance system, Tyler King says, “A lot of times trees had to be cut out, or the ditches had to be re-established because they had been silted in and filled up.” Ultimately, he says, “We had a flush truck out there to clean the lines up to get all the debris out.”
He described the scenes he encountered. “Every pipe was a little different. If there was silt in it, we’d flush it out and clean the pipe. If the pipe still had a floor, we were good with that, but many times you’d flush it out and realize there’s no floor of the pipe, and you start getting into the subgrade. Then we’d bring in gravel to start smoothing it out. If there were any holes in it, we would fill those in with gravel and get the pipe back to a round shape.” In cases where the ditches had washed out at the ends of the pipe, he says, crews shoveled in gravel to provide a new foundation. “We filled in gravel to give it stability underneath, and poured in Grout 12,000 to cover the void. It’s like a lot of things in rehab work—you spend more time in preparation than you do in actual application.”
Rebuilding the subgrade of each pipeline as they went, Krapff Reynolds crews applied Grout 12,000 from the Strong Company. It sets up at 12,000 psi to provide a foundation to support the pipe. Tyler King explains: “The bottoms of these pipes were completely gone. The beauty of the Grout 12,000 product is that you can apply it on the bottom and establish a good base again, and once you establish the base and have a good surface foundation, you can apply the Storm Seal pipe-lining product. We’d inspect it and make sure it’s all grouted up and looks good. Then we applied the Storm Seal.”
Using the Strong Company’s, trailer-mounted 35D applicator, crews applied Storm Seal pipe liner, which sets up to 9,000 psi when cured, spraying it on the interior of the corroded pipes. Jim King says the product’s 9,000 psi strength rating is critical to the success of the rehab. “You’re putting it on one inch thick, and that becomes your new pipe. You want the strength because you just have it on an inch thick, but it’s able to handle the loads from being underneath the roadbed.”
Pipeline rehabilitation is not all that Krapff Reynolds does. “We’re a full utility contractor with 19 excavators,” says Jim King, but he adds that 30 years ago Krapff Reynolds Construction’s president saw an opportunity for specializing in manhole rehab using Strong Company products. “He became a believer in their technology, and we’ve been an applicator since 1989.”
Jim King says the project on DeSoto Boulevard was completed in 2015 without inconveniencing residents because all of the work could be completed without excavation. “They never closed the road; they did it all off to the side,” says Tyler King. And Jim King notes that the town has since brought his firm in to perform additional work.
Linear Progression in Bremerton
Coastal Washington State is a year-round habitat of orca whales andis historically an important hatchery of Pacific salmon. Chance Berthiaume, stormwater permit coordinator for the City of Bremerton, WA, located on the Kitsap Peninsula within view of the orcas’ home base, says, “To meet the goals of trying to recover salmon and to protect the whales, water quality is a big deal. It’s critical. Ifwe don’t improve water quality we’re not going to be very effectiveif we’re trying to restore marine life or mammals.”
Bremerton maintains both its stormwater and wastewater collection system with a crew of about 14 people who, Berthiaume says, split the year between the two tasks, spending “half the year concentrating on stormwater and the other half of the year focused on sanitary sewer maintenance.” He says they are responsible for maintaining basic pipes, catch basins, and manholes, which they service using Vactor cleaning, as well devices such as CDS units, Jellyfish Filters, and other proprietary stormwater treatment systems. He says Bremerton’s technicians perform maintenance “on almost our entire system every year.”
With such a small crew for so many diverse functions, “Our guys have to be pretty diverse in their knowledge set,” he says.
“When you get into the proprietary systems, the manufacturers have come by and shown our guys how to maintain them and how to inspect them so they are familiar with the ins and outs of the proprietary devices, and we’ve been putting in more and more of them.”
Vaulting to Higher Standards
“We’re getting into a lot of different types of treatment vaults. One we’ve been doing for quite a few installations is called a Linear Modular Wetland system.” Berthiaume says it qualifies as a general use level designation (GULD) approved treatment system by the Department of Ecology and is approved by the Technology Assessment Protocol - Ecology (TAPE), a program established by the State of Washington for evaluating and approving emerging stormwater treatment BMPs. “These units provide a basic treatment stage, which is sediments and floatables control, and an enhanced stage, removing metals, oils, and other chemicals and phosphorus reduction,” he explains.
“With the linear Modular Wetlands you have a two-vault system. You have a pre-filter area that collects all the trash and any sediment that is going to fall out. Then the water flows into what I call the magic croutons. They are media inside canisters that have holes in them. That is where the oil and grease and most of the pollutants are filtered out. They are like a sponge, or little pieces of sponges, so that when water flows around them or comes into contact with that, the particulate attaches to those filters. Then the water flows into a large vault where it makes contact with fractured shale or some type of gravel material, and anything that is left, that didn’t get filtered out in the earlier stages, will attach to that second chamber’s media. The effluent from that is pretty well treated, to between 60 and 90% removal for basic and enhanced and phosphorus standards,” he explains.
According to Berthiaume, the manufacturer recommends that for the first year, the units should be inspected once a month “to see how they are performing. When you inspect them for the first year, you’ll get a real good feeling for how often it needs to be maintained to keep it operating.”
Berthiaume says he programs the maintenance schedule for Bremerton’s Linear Modular Wetlands based on these observations. “Essentially, we have three that need to be maintained quarterly. We have four that are semi-annual and four that are annual. It all depends on how much material gets into the treatment system. If you’re in an area that has a lot of leaves, like at the bottom of a hill in a neighborhood, that one is going to require more maintenance, but if you’re in a commercial parking lot, or a road system with no trees and not a lot of sediment, those will last for about a year before you have to clean them and maintain them.”
In selecting the type of treatment system to deploy at each site, Berthiaume uses the water-quality testing at the site for contaminants to identify the system that will treat the water to meet required standards. In addition, he says, it’s important to take into account maintenance requirements. Over the long term, “If it’s pretty simple to maintain, that’s better because it’s typically going to be cheaper, even if it costs more money to install or construct.”
To maintain Bremerton’s Linear Modular Wetlands, he says, “All you have to do is wash out the first area—the pretreatment area—vacuum all the leaves and sediment out, and then remove the croutons or sponges from their containers and put in new ones. It’s a pretty simple process.”
“It’s the best treatment system that we have available at the moment,” he says. The city recently installed 10 units and has scheduled 15 more installations for next year, with five new units going in this summer at sites selected based on their water-quality needs. On one project, Berthiaume says, they will be used to treat runoff from an urban arterial five-lane road that discharges into a closed-off bay that houses a number of shellfish beds. Berthiaume explains the sensitivity of the receiving waters: “It’s in a TMDL area, and the water doesn’t change out very often. It takes a couple of weeks for the water to change out with tide height. I have treatment vaults going in because it discharges into marine water bays.”
Bremerton’s overall philosophy for catch basins in general is to inspect every year regardless of condition. “Among our private property owners, we want to maintain 60% of catch basin capacity for sediment collection, so you have enough room for the water to enter, settle out all the solids, and then discharge or leave the structure,” says Berthiaume. “It’s a requirement from the Stormwater Manual for Western Washington and applies to any of the hard catch basins or manholes or detention systems. In some areas, I’m sure, we go beyond the manual out of concern for the local environment and the orcas. That’s why we clean all of our system once a year. It’s not required that we do that but we do it anyhow.”