Water Monitoring Flows Toward High-Tech Solutions

April 14, 2004
A municipality might need to set up a water monitoring program for various reasons–to meet permit requirements, restore aquatic habitat, or monitor pollutant levels–but, increasingly, monitoring protocols are becoming more similar. One common factor is that: more testing is being done with automated systems, which not only save on manpower costs but also allow for the collection of more comprehensive or event-targeted data. In addition, as more oversight agencies want to review the collected water-quality data, computer interfaces that collate the data into reports are becoming standard equipment in many stormwater management agencies.Making Streams Safe for FishConcern for wildlife, and a state ecology grant, prompted the city of Federal Way, WA, to add more equipment and testing sites to its monitoring program.“We received a $500,000 grant from Washington’s Department of Ecology for a stream restoration project on West Hylebos Creek, an important salmon-bearing stream in Federal Way,” explains Dan Smith, Surface Water Quality Program coordinator. “A component of that grant was to monitor water quality in four areas. Although we were already checking dissolved oxygen, pH, specific conductivity, and temperature, we then needed to monitor turbidity, which is critical to salmon habitat. Turbidity is an indicator of sediment in the stream. Nasty particles–heavy metals, for instance–can adhere to sediment, and can obliterate the fish spawning areas. Sediment can also damage salmons’ gills.”Smith’s department, which manages all of Federal Way’s surface water, stormwater pipes, and retention ponds, keeps tabs on all that water before it flows into local streams, creeks, lakes, and ponds and eventually to Puget Sound. Federal Way, a town of approximately 83,000 residents, is located about half-way between Seattle and Tacoma.“We will be under the Phase II permit from the state, probably in 2005,” says Smith. “We have five sites where we have employed YSI’s 600XL water- quality sonde, an automated water-quality measurement device that takes readings every 30 minutes, 24/7. Once a month we go to the sites with an Isco 581 Rapid Transfer Device to download that data. We return to our office and upload the data to our PC for evaluation.”As it’s designed to operate in fresh, sea, or polluted water, the YSI 600XL sonde works well at Federal Way’s various sites; some streams receive influx from Puget Sound. The 600XL measures dissolved oxygen, temperature, conductivity, oxidation-reduction potential (ORP), salinity, vented level, depth, pH, total dissolved solids (TDS), and specific conductance.  The sonde is compatible with the software EcoWatch for Windows to aid with data analysis.Some read times are more important than others. “We are concerned with first flush, as we have really dry summers,” Smith reports. “If we have a rain, we can see temperature increases in streams because the hot asphalt heats the water runoff. Our rainy season starts about October, and the onset of heavy rains can rinse out streets and pipes and push pollutants into waterways–that’s something we can measure. Dissolved oxygen, pH, and turbidity could be affected by those pollutants.”
For the salmon study, Federal Way needed different readings and equipment. “At four other sites in the city we upgraded to a YSI 6920 sonde, which includes the same parameters as the 600XL, but additionally monitors turbidity,” Smith explains. “We are also implementing a rigorous monthly field calibration of YSI equipment to comply with Washington’s Department of Ecology Quality Assurance requirements.”In addition to measuring more parameters (open-channel flow, nitrate-nitrogen, rhodamine, chlorophyll, ammonium-nitrogen, ammonia, turbidity, chloride), the YSI 6920 sonde also has a large memory capacity, with the ability to store 150,000 readings. Its power supply, eight AA alkaline cells, should last 25 to 30 days while taking 15-minute sampling intervals at 25°C. Its turbidity sensor, which is not affected by variations in ambient light, has a self-cleaning feature. For other applications, a self-cleaning chlorophyll sensor may be installed instead of the turbidity sensor. With appropriate add-ons, the YSI 6920 also has the capability to transmit data via radio, phone, or satellite. Smith physically goes to the sites to retrieve the data. “We have a YSI 650 MDS handheld unit that connects by cable to the 6920 and we download the data. The automated samplers give us a continuous record of water quality in our streams that we can track over time–rather than basing assumptions on a few grab samples that might give us just a ‘snapshot’ of conditions. Our program includes monthly laboratory and field calibration; we’re collecting lots of documentation of instrument performance.” With all this automatic collection, are there instances when they’ll still send people out with hand-held samplers? “We have other YSI handheld equipment, and we may have to do the old ‘jar on a string’ sample in stormwater sewers or streams, and then take that to the lab for analysis,” Smith says.“In the field, we also use Hach colormetric handhelds, which contain a reagent kit, with different chemicals for testing,” he explains. “When you add different chemicals to a sample of water, you’ll compare the intensity of the color change to the kit’s chart, which will tell you what contaminant is in the water. We loan these kits out to our Stream Team volunteers, who test water in eight different locations. We track the measurements they take, as well as our own.“We also have an ongoing monitoring program for metals, pesticides, and nutrient levels. We need to educate citizens about nonpoint-pollution sources; lawn fertilizers can get into waters and cause problems, and people shouldn’t wash their cars and let that dirty water run off into storm sewers, as the detergents contain phosphorous. We do monitor for those, but we can’t be the ‘car wash police,'” he concludes.Collection for Compliance
Chattanooga, TN, monitors its stormwater streams at least twice a week, to ensure it’s in compliance with federal and state regulations. The city’s water- quality technicians carry In-Situ  MP (Multi-Parameter) Troll 9000 water-quality monitors.With available options, the monitors can measure dissolved oxygen, conductivity, resistivity, TDS, temperature, pH, ORP, salinity, level, pressure, and depth. It also records open channel flow, barometric pressure, nitrate, chloride, ammonium, ammonia, and turbidity. The models that Chattanooga uses for its purposes measure only barometric pressure and turbidity.“We have a lot of WPA [Work Projects Administration] ditches from the 1940s, which were built to reduce malaria. A lot of them were covered over, but they still produce a lot of groundwater flow. For our current big sampling project, which is monitoring these streams, we try to calibrate once a week,” says Water Quality Coordinator Doug Fritz. “On Tuesday and Thursday, starting around 8 a.m., we do samples. We also take fecal samples, and have those into the office by 11 a.m.“We do our sampling in about 13 locations over two 2 miles,” he explains. “In our testing, we’re mostly looking for fecal, pH, dissolved oxygen O2, and temperature. We’re trying to isolate fecal. In our part of town, the stormwater is separate from sewage. However, we have seven 7 square miles of combined [sanitary] sewer and stormwater. We also monitor to see when streams go below state standards for dissolved O2oxygen limits, and we do ambient monitoring, per NPDES permit requirements. “The Troll 9000s are also used for ambient and fecal monitoring, both baseline and storm events, around the city and its streams–such as the North Market Street branch of the Tennessee River–once a month. If we find illicit discharges, we track them back to the source.”Concerned with first-flush, Chattanooga is also installing an automatic sampling system. “We’re setting up composite samples in the lower watershed, and will have pollution loading readings during storm events. We have ISCO 4250 flow meters and 3700 composite samplers, which are triggered by rainfall amounts and rising water levels. The May ’03 flood took out some of them, so we have to replace some. The total number of monitors will be about 12 around the city, to monitor pollutant loading. We want to be ahead of Tennessee’s requirements. We identify point sources of pollution; in new developments, for example, this is mostly silt, BOD [biochemical oxygen demand], and nitrates from fertilizers,” Fritz saysThe automatic meters also inform Fritz that the stormwater system is working as it should. “The city has a lot of microburst rainfalls. When they line up with our meters, we can pinpoint flow, and know our culverts are running full. Composite readings come to our office through dedicated phone line modems,” he explains. “We currently have hardlines; the next installations will be solar-powered and cellular. However, there are still times when we have to go out and get samples for lab testing.” “After a storm, grab samples have to be done on first flush,” adds Water Quality Technician Jeremy Swilley. “Using the Troll 9000 with turbidity meter, I try to determine pollutant loading off construction sites. We have to determine compliance. We’re currently responsible for monitoring 147 square miles.“We had used other samplers in the past, to routinely run dissolved O2oxygen, pH, and other parameters. The Troll tells us the turbidity along with those, so we only have one handheld unit to carry around.”Part of Tennessee’s water-quality standards mentions “objectionable color,” but, Fritz says, “that doesn’t help us with compliance. We have to find acceptable aesthetic standards within the community and government. Even with a silt fence, stormwater can come through cloudy, especially in areas of clay soil, so we’re trying to come up with standards of turbidity and suspended solids. In the past, we’ve had citizen complaints, but couldn’t find a violation.”Monitors will be installed in each of the city’s 10 watersheds, and two others will be installed at jurisdictional boundaries, so Chattanooga can measure what is coming into the city from someplace else. What can they it expect to find?“We’re not so much worried about mercury; it’s only when we get into industrial samples that we look for metals. We have a lot of zinc issues. Industrial plants are probably the main source, although zinc comes out of autos’ brakes, too. We’ve had some evidence of atmospheric deposition, but we don’t know yet if the zinc is coming from the air. Background levels of zinc are high in some parts of the state,” Fritz says. “As the Tennessee River bisects the city, we’re looking to keep that clean.”Watching Only the Water
Sometimes it’s primarily the quantity of water that’s of concern. In Hawaii,department of transportation workers use a solar-powered rain gauge to constantly monitor rainfall amounts at multiple construction sites, without leaving their desks. “Hawaii Department of Transportation [HDOT] uses the rain gauge data for its monthly summary of compliance inspections for construction activities’ general permits,” says HDOT Resident Engineer Tom Jenkins.Durham Geo Slope Indicator’s solar-powered Cyber Rain Gauge, with a self-emptying tipping bucket, automatically reports rainfall amounts every 15 minutes to a secure Web site through a wireless, global satellite communications network. Subscribing customers can access the data through a common Web browser and download it to their desktops for manipulation and graphing.In one Hawaii application, the Cyber Rain Gauge monitors rainfall on road construction sites in Hawaii–data required both for NPDES permits and for scheduling construction activities. The process has helped minimize workers’ costly trips to job sites while still providing good documentation for the state.The state’s rigorous inspection schedule requires inspections to take place at least once a week or within 24 hours of any rainfall 0.5 in. or greater within a 24-hr. period. That means that if more than half an inch of rain falls on every day of the month, an inspection is conducted every day. All sediment-control measures are checked weekly in dry periods but within 24 hours after any rainfall of 0.5 in., so during prolonged rainfall, daily checking is necessary. The state also has requirements to record 24-hr. rainfall data each day.Remote Readings, Downloadable Data
“We’re not testing for water quality but water quantity,” explains Jim Bruce, general manager of Hardin County (KY) Water District #1. “We’re monitoring rainfall and stream flow at three locations in Radcliff for a future request to the Kentucky Division of Water to increase our water withdrawal permit amount. We’re hoping to expand our water treatment plant, but until we know how much total raw water we have available at the site, and how much the state will allow for a withdrawal permit, we cannot proceed with our plant expansion design.”The district is using solar-powered automatic samplers from High Tide Technologies in Bowling Green, KY, to check continual flow. The samplers use an ultrasonic depth-level device, which reflects off the stream surface; the machine then interpolates that data to a gallon-per-day flow rate. High Tide uses GEO and LEO satellite, AMPS and GSM cellular, and RF network communications, combined with off-the-shelf hardware and software, to deliver data. “Devices were installed at the Rough River in southwest Kentucky, Hardin County, at the Head of Rough stream that flows into Rough River, and at Pirtle Spring, which flows at our water plant site–our main source of water. All these sites are within a mile of each other; the daily flow rate comes out in millions of gallons per day,” Bruce says. “The High Tide equipment transmits to a satellite, and down to their Bowling Green offices. The calculations are all done at High Tide’s office; although the data is coming in all the time, they average the data for a 24-hour period, and load it to the Web, so we can get the data from our assigned site. After two years, we will get the full report on a spreadsheet, so we can petition the state to allow us to take more water than our current permit allows.”None of Bruce’s people needs to take readings with hand-held samplers. “That’s what’s nice about it,” he concludes. “Another water company in the area did a study like we are doing, and they had to go out every day to check the water–ours is done automatically. We have already met with the state once, and it was impressed with the information.”

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