Keeping Tabs on the H2O
Protecting creeks, patrolling bays, and evaluating low-cost BMPs
Water monitoring has a wide variety of applications, from determining amounts of foreign matter in potable water supplies to diagnosing the long-term health of an ocean or a marsh. State and federal officials must be concerned about runoff, as governing bodies negotiate with private concerns to develop guidelines and regulations. But behind all the practical reasons for and ramifications of water monitoring lies scientific query that seeks to use data as its own platform for continuing hypothesis and research.
Francesco Peri, managing director for the Center for Coastal Environmental Sensing Networks (CESN), is an electrical engineer specializing in software engineering. As chief engineer for the department of environmental earth and ocean science at the University of Massachusetts, Boston, he provides technical and engineering support to projects. “I transform dreams,” Peri says.
One such dream was the brainchild of scientists at the UMass Boston CESN, who, under the leadership of Dr. Robert Chen, have developed and deployed five environmental monitoring buoys in Boston’s Neponset River watershed as part of a two-year program funded by the Department of Energy and the Office of Naval Research. The buoys are tracking near-shore climate conditions and measuring colored dissolved organic matter (CDOM) content as part of CESN’s Boston Environmental Area Coastal Observation Network (BEACON) project.
The Neponset River, a relatively small 20-mile waterway that forms the southern boundary of Boston, is fed by a drainage basin of approximately 130 square miles that is home to some 250,000 people.
“The project is a test bed,” Peri says. “In the Neponset, we have a small, self-contained waterway, manageable in size, which allows us to create a networking platform that is applicable in scale to larger projects. By adding a sensory layer to the environment, we are able to create a sensory network that perceives real-time phenomena.”
Peri says that while monitoring buoys in themselves are already in use across the country, this project is unusual in that it provides a “technological playground” that allows any number of additional scientific entities to interface with its network, providing additional information and feedback on a continual basis. “It will provide a good interface for decision makers,” he says.
By combining monthly in situ water monitoring from a research vessel with data from satellite imagery, it has been possible to correlate the two and establish a calibration curve, Peri says. “On days when it is not feasible to enter the area physically, we can make inferences.”
In setting up the project, the group divided the watershed into subwatersheds of predominant land-use type. After identifying 10 such types, they determined that the three most significant were forest, urban, and golf courses, in that order. “Our goal was to determine the major contributors to the overall carbon cycle in order to acknowledge the effect of changes produced by colored dissolved organic matter,” Peri says, adding that the focus was not to concentrate on pollutants as such, but to create a model for this and other applications. “We want to keep the model open.”
Fluorescence detection of CDOM takes advantage of CDOM’s natural fluorescent property of absorbing UV light and fluorescing blue light. Also known as gelbstoff, CDOM occurs naturally in aquatic environments as a result of tannins released from decaying plant material. As a byproduct of photosynthesis, chlorophyll is a key indicator of phytoplankton activity. However, while CDOM and chlorophyll absorb in the same spectral range, selective sensoring can discriminate between them, Peri says.
Working with a cellular-based telemetry system provided by Onset, a Cape Cod-area company that manufactures data loggers and other measuring equipment, CESN placed five solar-powered environmental monitoring buoys and three fixed, electrically powered monitoring stations in the watershed, at depths ranging from 1 to 30 feet. The foam buoys, measuring 30 inches in diameter at the main barrel, weigh between 80 and 100 pounds each and have instruments mounted on them to detect measurements from both water and air.
As part of the project, which currently is funded through 2012, a scaled-down version has been extended to the Hudson River. “We did a subset of Neponset,” Peri says, “placing buoys in the major tributaries of the river and surveying them both with satellite and in situ. We received the same degree of correlation that we had seen in the Neponset.”
Peri says the group is pleased with the initial results. “We can see immediate application to a larger watershed,” he says. With a testbed of innovative sensor technologies, the future holds promise for technology to advance. “With a sensory network that perceives natural phenomena, we can send that information to a cellular network’s servers where the data can then be stored and programs can be written and delivered to software agents, which can then transfer the data to provide information not only to a web page but to a computer-based database that can be accessed by other scientists.”
In other words, what happens in Boston today can be experienced immediately in cyberspace and applied: science gone global.
Conservation, One Bay at a Time
Maine’s Casco Bay has one of the busiest oil ports on the East Coast, and its 985-square-mile watershed is home to one-fifth of the state’s population on only 3% of its land area. Home to Portland, by far the largest city in Maine with a metro population of 230,000, the area is experiencing urban and suburban growth that threatens its Atlantic watershed.
Biologist Mike Doan is the research associate for the Friends of Casco Bay (FOCB), a 21-year program with eight staff members and a host of volunteers who sample the bay and conduct outreach programs on its behalf. “We are a nonprofit marine stewardship organization, the seventh Waterkeeper program in existence, and staff member Joe Payne was one of the original baykeepers in the international Waterkeeper Alliance,” Doan says. Founded in 1999 by environmental attorney and activist Robert F. Kennedy Jr. and several veteran waterkeepers, including Casco Bay’s, Waterkeeper Alliance is a global movement of close to 200 on-the-water advocates who patrol and protect over 100,000 miles of rivers, streams, and coastlines in North and South America, Europe, Australia, Asia, and Africa.
The FOCB’s programs range from advocating best management practices (BMPs) for dredging in Portland’s working harbor to providing oil spill response and communicating with homeowners and municipalities in developing better practices to avoid contaminated runoff.
Using 6600 series V2 sondes manufactured by YSI Incorporated, FOCB conducts multiparameter monitoring of the bay. “We can take these handheld data loggers into the field at depths from the surface to 30 meters, lower them into the water by cable, and push a button to record,” Doan says. “We get a baseline by sampling once a month, year-round; we’ve been doing this regularly for a 20-year data set.”
A YSI sonde is also used to sample unattended at sites that demonstrate reduced water quality, Doan says. “Rather than taking the sonde into the field and lowering by cable, as we do in our ongoing baseline monitoring, we may also leave the sonde at a site that has demonstrated poor water quality and program it to automatically collect data every hour for a week or two. In this way, we get a better idea of how the site functions over time. This is a more in-depth look at a particular site and allows us to determine why the site has low water quality.”
Although the organization has collected extensive data on dissolved oxygen, pH, and phytoplankton and chlorophyll levels at more than 50 sites around the bay, the primary focus is nitrogen. Its Nitrogen Pollution Initiative is funded in part by a $10,000 “Minding the Planet” grant from the YSI Foundation. “We mainly look at stormwater runoff containing pesticides and nitrogen,” Doan says.
As Baykeeper, Payne conducts outreach programs to explain the effects of fertilizers and pesticides on the watershed and to suggest alternative practices. “Dosage and timing of application are two major issues,” Doan says.
Another major concern for the group is the Portland area’s combined sewer overflows (CSOs). “Older pipes combine waste with runoff, and large rain events can overwhelm the system,” Doan explains.
While Portland has long been a busy working port, recreational traffic has increased exponentially. More cruise ships, day cruisers, and even live-aboard boaters exacerbate water-quality problems. Although Maine has a ban on overboard sewage dumping for smaller vessels within 3 miles of the harbor, enforcement has been limited, Doan says. Casco Bay’s newly designated no-discharge zone prohibits large passenger ships from discharging both treated and untreated sewage into the bay. “It was a victory for the bay,” Doan says.
|Photo: MIKE DOAN
In addition, an increasing number of marinas have installed pump-out stations, and FOCB also is doing its part. “We own our own pump-out boat that goes from boat to boat in the harbor and provides service,” Doan says. “Our ongoing goal is to change behavior. We are the eyes and ears of the watershed.”
The Hunt for Low-Cost, Low-Maintenance Ditch BMPs
Engineer Jim Crawford and environmental scientist Jason Finlinson work for the King County Department of Transportation’s Roads Maintenance Section Environmental Unit in Renton, WA, about 15 miles east of Seattle. They are two of the principal players in a grant-funded project to develop BMPs for treating stormwater pollutants and controlling flow within roadside ditches, particularly BMPs that could be applied throughout the region.
“NPDES [National Pollutant Discharge Elimination System] municipal permits have placed a new focus on municipalities, seeing cities and counties as sources for unregulated, nonpoint-source discharge of stormwater,” Crawford says. “The Phase I municipal permit issued by Washington State in 2007 focuses on stormwater and covers the largest cities and counties. In anticipation of increasing stormwater regulation, we developed this project to study stormwater BMPs in roadside ditches. We were awarded a grant in 2008 by Washington State’s Department of Ecology under the Stormwater Management Implementational Grant Program. In January 2010, we are midway through our second year of field projects.”
Unincorporated King County has nearly 2,000 miles of county roadways, where the surrounding property generally ranges from rural to suburban land uses. Some of the stormwater in King County’s roadside ditches enters receiving waters and eventually drains to Puget Sound.
The project, comprising eight distinct studies around King County, was intended to evaluate the effectiveness of simple, low-cost, low-maintenance BMPs placed in existing roadside ditches as an alternative to traditional stormwater treatments such as retention ponds and sand-filter systems. One goal has been to utilize the existing right of way for stormwater treatment. Half of these studies evaluated water-quality BMPs, and the other half focused on controlling flow. “There have been many studies on large highway systems but few on ditches along smaller county roadways within limited rights of way,” Crawford says.
“The project involved designing and developing a set of roadside ditch BMPs that were low-cost and easily installed by road crews,” Finlinson says. “In the design phase, from 2008 to 2009, we contacted local experts in stormwater management and low-impact development [LID] for input and guidance. Common themes [of their responses] were to minimize design complexity and to consider the use of compost as a treatment medium. Some concerns were raised about the tendency of various filter media to blind-off. We were also advised to consider the potential maintenance needs of the media and/or the BMP structure.”
At 148th Avenue SE, which Crawford calls “last year’s winner,” the new BMPs resulted in an average 50% reduction in total suspended solids (TSS). “In the course of the first year of the project, we learned that BMPS were reducing sediment loads, measured as TSS and turbidity,” Crawford says. “We didn’t know that to begin with; it was part of our goal to characterize the stormwater in our ditches and find out what we were dealing with.”
Flow measurements and water-quality samples were collected upstream and downstream from water-quality BMP project sites. Flow composite samples were collected for TSS, total Kjeldahl nitrogen (TKN), nitrate-nitrite, orthophosphate phosphorous, dissolved metals, and polycyclic aromatic hydrocarbons (PAHs). Grab samples are used to determine total petroleum hydrocarbons (TPHs) and fecal coliform. Water temperature was measured continuously in the roadside ditch.
To measure the flow, trapezoidal flumes were placed in the ditch at upstream and downstream monitoring locations, with Isco bubble meters used in conjunction with the flumes to log data and convert water level to flow in gallons per minute. An Isco 6712 autosampler, receiving flow signals from the bubble meter, collected upstream and downstream flow composited samples. Temperature measurements were collected using an Onset HOBO Pro v2 water temperature logger.
“For our BMP, we are using a modified rock check dam with a treatment cell inside,” Crawford says.
“For the first-year studies, we used a geotextile fabric filled with compost. We needed to meet county road design standards to ensure continued function of the ditch to convey stormwater flow while minimizing the potential for flooding, maintaining the structural integrity of the roadway, and making sure certain overall public safety goals were accomplished,” Finlinson says.
|Image: King County, Washington
Total suspended solids monitoring data from King County’s BMP project
Treatment of stormwater in roadside ditches is difficult because no two ditches are the same, Crawford says. “It depends on traffic and land use in the surrounding area. Governing bodies would like a one-size-fits-all solution, but it’s more a site-by-site prescription.”
Another predominant issue is the Seattle area’s proclivity for extreme weather patterns. “Seattle dries out dramatically in summer,” Crawford says. “There is virtually no rain in July; then if we get a storm in late August, the water sinks into the soil. In winter’s wet season, the ground is saturated and the stormwater runoff is significant, with high flows frequently overtopping the BMPs.”
Finlinson adds, “The BMPs originally were designed to capture first-flush events after a dry spell and low storm conditions while allowing higher storm flows to pass. So far, the BMPs have held up to high flows without failure.”
“Our goal originally was filtration,” Finlinson says. “We are seeing that the BMPs are reducing energy of the incoming storm flow. They create pools upstream of each BMP, thereby reducing the scouring velocity and creating small settling basins for sediment deposition. By increasing the number of BMPs in the second year, we are increasing the storage capacity and treatment.”
Finlinson and Crawford emphasize that the present BMPs are just one tool in a “toolbox” of possibilities. “This is the set we picked to study,” Crawford says. “For example, in our current study, there is one ditch with flashy flows and a steep gradient resulting in scouring effects. A traditional solution would be to protect the ditch by rock-lining. These BMPs, which contain compost socks, created a step-pool effect that knocks out the energy from the storm flow, while the compost provides a filtering effect. Continuous turbidity monitoring, along with flow-weighted composite samples, are showing a measurable sediment reduction across the BMPs.”
King County Roads Maintenance has used monitoring equipment from YSI since 2001 for various water-quality monitoring projects and is now deploying YSI 6920 and 600OMS sondes for continuous monitoring of turbidity levels. “In general, stormwater monitoring programs focus on collecting flow-weighted composite samples to characterize stormwater chemistry,” Crawford says. “The sampling is costly, labor-intensive, and difficult, with a high failure rate. Grab samples provide only snapshots that tend not to be representative of the storm. A continuous monitoring sonde, like the YSI, can be set up to measure the turbidity at regular intervals. We can deploy the sondes upstream and downstream of the BMPs for extended periods of time before we pull the information.”
The new BMPs appear to be doing their job. “After 18 months of studies, we have learned that our BMPs reduce TSS and turbidity,” Crawford says. “From a treatment perspective, with the reduction of solids, we are seeing a reduction in associated metals and PAHs. From an erosion control perspective, if we can reduce the energy of the storm flows, we can reduce scouring and improve the stormwater quality in roadside ditches.”
Saving a Creek Becomes More Than a Job for Motivated Crews
Tokul Creek in King County, WA, long has held the interest of widely divergent entities, from the Tulalip Tribes to forest products company Weyerhaeuser. The Washington Department of Fish and Wildlife (WDFW) has operated a fish hatchery on the banks of lower Tokul Creek since the early 1900s. And in September 2010, the creek was the starring character in a 30-day collaborative effort by the Washington State Department of Transportation (WSDOT) and Northwest Construction, who worked as quickly as possible to remove debris and to repair scouring that was threatening the bridge abutments under SR 202 near Snoqualmie Falls.
“Tokul Creek would be called a river in any other state,” says Maroa Velice, WSDOT’s environmental compliance inspector. “The average daily flow of Tokul in September was reputed to be roughly 22,000 gpm [gallons per minute], with a peak flow of 44,883 gpm. In comparison, the flood flow in October commonly exceeds 131,500 gpm, so we were well motivated to get the job done quickly.”
Located in a deep, 100-foot-wide canyon with a 50-foot-wide streambed and 40-foot slopes averaging 1.5:1, the creek offered several challenges. “This was not your typical linear construction job, because crews had to divert the creek in order to get equipment into the creek bed,” Velice says. “The bypass system was composed of four 400-foot, 24-inch HDPE pipes selected for their strength and flexibility. They had to curve to the streambed and be strong enough to contain the flow, which was 50 to 75 cubic feet per second. These pipes were welded together at the top of the canyon, then passed down one side of the wall, pulled and pushed downstream with an excavator, then pulled back upstream and positioned.”
Once the pumps were in place, a large (8-foot high by 20-foot wide by 80-foot long) aqua dam was dropped into the canyon by crane and unrolled across the streambed. Meanwhile, a bench was excavated below and alongside the bridge to provide a site for five Godwin Dri-Prime pumps needed for emergency bypass. A block wall was installed behind the pumps. Two additional 24-inch pipes were added for the emergency diversion system in case of flash-flooding. Cranes set filters into the streambed and redundant pumps were placed downstream to collect seepage. A second downstream aqua dam and redundant pump system also were installed.
|Photos: KING COUNTY, WASHINGTON
Trapezoidal flumes placed in ditches helped to measure the flow.
Next came the fish removal. “A team of fish biologists came for two days and stunned the fish, then counted them and released them downstream,” Velice says. “Half a mile down from the job site is a Tokul Creek Fish Hatchery, so we had to be really careful with turbidity. The hatchery was grateful for the fish count; it had been too costly for them to undertake the job.”
Fish removal was a team effort, Velice says. “The really cool part of this fish exclusion was that the contractor’s crew, who really couldn’t pursue any construction work until the fish were out of the creek bed, pitched in to help the biologists pick up all the little fish. Here were all these burly guys playing in the puddles like a bunch of school kids – laughing and joking and enjoying every minute of it. It was hilarious.”
Water monitoring was continuous on the site. “We monitored three to five times a day, and we had an inspector on at night,” Velice says. ”Putting in the pipes disturbed the creek, so every time pipes were maneuvered in the water, either I or my associate went downstream and tested the water quality. When we cut through the logjam, wood chips floated down to the hatchery, but that was a minimal disturbance. Precautions were extraordinary: All the construction equipment had vegetable-based lubricant, even the chain saws. They drained out the petroleum, put in vegetable oil, and drained out the equipment once or twice more until it was clean. All of the rocks placed in the stream were washed over and over to remove any soil.”
Velice, who inspects DOT construction sites in several Washington locations, uses Hach’s 2100P portable turbidimeter and sensION 1 pH Meter. “The 2100P holds calibration really well,” Velice says.
“The hydrologist placed three-man rock in a pattern resembling the dots on a five die, with approximately 15 feet between them. This deflected the water’s energy in the scour area and provided better spawning habit for
Velice explains, “Washington allows only 5.0 NTUs [nephelometric turbidity units] above the background water of this creek. When we tested upstream, the water was ‘clear,’ at 1.3 NTUs. Two hundred feet down from the work zone we tested again; we did not go over the limit throughout the scour work.”
Once the 1,500-plus fish had been counted, the creek was armored with huge boulders. “These were huge, six-man rocks; only two or three would fit on a trailer,” Velice says. “A large excavator was posted at the top of the canyon. They would run another excavator down to the bottom of the creek bed with a cable; then yet another excavator was cabled down to a bench. Finally, the rocks would be removed from the truck, handed off from one excavator to another, and positioned tightly in the streambed. But first crews had to scrape the bank clean and lay down fabric before positioning the rock in the bank.”
Over time, three different bridges have spanned Tokul Creek. The first was a wooden trestle bridge and the other two were concrete. Remnants of the first two were still in the creek, with the second bridge’s concrete piers causing the logjam that was tearing at the most recent bridge and scouring the creek banks. All of the detritus had to be removed.
“We reintroduced the water very slowly in order to avoid turbidity rushes,” Velice says. “It took two days to cut through all of the pipes, with the emergency system going full blast. At dawn on the second day of decommissioning the bypass system, we could see that the downstream dam had collapsed. We built backup pea gravel dams for the downstream dam first thing in the morning, before we cut the last two gravity-flow pipes. (The first two pipes had been cut the first day of decommissioning.)
|Photos: Washington State Dot
Tokul Creek in King County, WA
“Then it happened. The upstream aqua dam, held up with guy ropes and tied off to trees, collapsed when the guy lines snapped. The dam rolled over and almost killed a crew member working downstream. We got a huge wash of dirty water from behind the dam. It wasn’t until after the last of the four gravity pipes had been cut that the large upstream dam collapsed. We thought we were home free, and then disaster struck. It was a miracle, but thanks to the rock-washing throughout the construction process, the event lasted less than 30 minutes before the turbidity went down to 28 NTUs. In another half hour it had cleared to background. We never exceeded 263 NTUs. We have had much worse in major storm events; 263 was not bad, and it cleared rapidly. It was heartbreaking, but it could have been much worse.”
The fishery staff, contacted at once, did not panic. “Actually, they were ready for us to decommission the bypass system, so they had already moved their fish to tanks,” Velice says. “They told us they had expected high turbidity off and on during our job and had only experienced one plume, which was not as bad as they got during an average rainstorm. They complimented us on a remarkable job.”
Velice says that everyone on the job was “crestfallen” when the dams collapsed. By this time in the project they had become a team, if not a real family. “Our contractor, Northwest Construction, knew all about compliance and was determined to have this be a landmark job. This crew was expert at stream bypass, and they were handpicked for their positive attitudes and stellar records. They worked with me every step of the way and would do anything I asked in the way of compliance.”
Velice says working on Tokul Creek was a spiritual experience. “That gorgeous stream thanked us for the job we did, but she also showed us who was boss.”
Months later, Velice was speaking on another matter with the project superintendent for the Tokul job. “He actually said, ‘I am really proud of that job. It was like working in Nature’s Cathedral.’”
Author's Bio: Mary Ellen Hare is a frequent contributor to Forester Media publications.