Many types of software are available to stormwater management professionals for monitoring, analysis, and program management related to stormwater and combined sewers. Some of their applications help determine the size and number of best management practices (BMPs) that are needed for a particular drainage area and evaluate their effectiveness. Some track parameters such as the quantity and quality of runoff, and the flow rate, flow depth, and quality of water in each pipe, channel, and lake. Some generate nonpoint-source pollutant loadings associated with the runoff for wasteload allocation studies, and others help municipal permit holders comply with their National Pollutant Discharge Elimination System (NPDES) permits.
The first component of a stormwater management program is collecting data. Water data includes stage, elevation, flow, temperature, specific conductivity, and dissolved oxygen. Weather data includes precipitation, wind speed and direction, humidity, and temperature.
For its continuous hydrologic monitoring program, the city of Lake Oswego, OR, collects time series, or continuous, data at its hydrologic monitoring stations and weather stations every 15 minutes, 365 days a year.
According to David Gilbey, water-quality program coordinator for the city, “Time series data is a sequence of data points, measured typically at a uniform time intervals–every 15 minutes, for example. Examples of time series include hourly precipitation measurements or dissolved oxygen-reading measurements. Time series data collection is made easier through the use of real-time data telemetry, a technology that allows data collection and station management to be made at a distance.”
With real-time telemetry, data are transferred over mechanisms such as radio systems, telephone or computer networks, or optical links. Gilbey uses Aquarius software to collect, store, grade, and analyze the data.
The city of San Francisco Public Utilities Commission uses GIS (geographic information system) software from Esri for its “Only Rain Down the Drain” program. GIS captures, stores, edits, analyzes, shares, and displays all types of geographical data, from multiple sources.
Users may view their data as tables in a database, or as a map. GIS provides users with a set of maps. Each map is a layer of data, for example, the locations of stormwater pipes, lakes, rivers, and monitoring stations. Layered on top of each other, the maps show relationships, patterns, and trends, which allow users to visualize data in a way they can understand easily. GIS maps help users analyze current conditions, anticipate future ones, solve problems, make decisions, and evaluate results, all of which they may easily share.
Users also may view GIS as a model. Because modeling shows data sets in three dimensions, users can calculate the slope, aspect, roughness or smoothness of the terrain, and soil types, all of which affect the amount and direction of the surface flow, as well as the boundaries of the catchment area.
City of Lake Oswego
In the case of the city of Lake Oswego, an illicit discharge into the lake led to a monetary penalty for the water-quality violation. The city offset the penalty by agreeing to fund a supplemental environmental project that would improve its watersheds in some way, says Gilbey.
In the fall of 2007, the city implemented a continuous hydrologic monitoring program. It installed two water-quality gaging stations that assist in the assessment of runoff and pollution in the watershed by collecting dissolved oxygen, specific conductivity, pH, temperature, turbidity, and water level data, every 15 minutes.
“The installation of the hydrologic monitoring stations was only one element of the program,” says Gilbey. “The city also needed an efficient way to collect, grade, analyze, and store the data collected.”
Most municipalities don’t have the time or skill to develop a proprietary tool in-house to perform those functions when they’re associated with time series data, Gilbey says. He chose Aquarius software solutions from Aquatic Informatics Inc. in Vancouver, Canada.
“In 2005, I met the Aquarius people at a conference in Seattle,” he says. “They’d done this kind of fieldwork. They really knew the ins and outs of collecting high-quality water-quality and hydrologic data, including the efficiency issues of dealing with high-frequency time series data. They really knew the value of data–and data of a known quality.”
Aquarius Workstation coupled with Aquarius Server is a data management platform with a Web-based user interface called Springboard that gives users access to their data anywhere, anytime. Aquarius Workstation streamlines the collection, storage, and grading of data from the city’s hydrologic monitoring stations, which allows Gilbey to process data efficiently. Workstation also allows him to use the same methodologies and tools as the US Geological Survey and Water Survey Canada, as well as import data from a wide variety of external databases.
“Having the correct tools to analyze our monitoring data efficiently really makes a difference,” says Gilbey. He uses Aquarius to improve all aspects of the city’s stormwater management program, from detecting and eliminating illegal discharges to minimizing pollutants to creating custom annual reports.
The city of Lake Oswego, approximately 8 miles southwest of Portland, has a population of 37,000. It manages 150 miles of streams and 150 miles of storm pipes. The surroundings are very hilly, and the soils are high in phosphorus, which can lead to excess algal growth.
Oswego Lake has a total maximum daily load (TMDL) for phosphorus. Springbrook Creek, which empties into the lake, has a TMDL for bacteria and phosphorus. Tryon Creek and the Tualatin River, which both empty into the Willamette River, have thermal pollution (high temperatures). “Phosphorus and runoff volume are our hot buttons,” says Gilbey. “Phosphorus is mobilized by soil erosion, which is intensified by the increased runoff from urban development in the area.”
The city uses total suspended solids (TSS) concentrations and total phosphorus concentrations coupled with the time series data sets of pH, temperature, turbidity, and discharge to better characterize the phosphorus concentrations entering Oswego Lake and the watershed. According the recently updated Oswego Lake TMDL, it is estimated that 65% of the annual source contributions of total phosphorus come from the surrounding watershed, probably from urban pollution sources and bank erosion.
Monitoring. The first step in the city’s monitoring program is collecting data.
Aquarius Workstation was developed for use with time series data. Each of the city’s two water-quality gaging stations, at Springbrook Creek and Lost Dog Creek, contains a datasonde, which records water-quality data; a level measurement device; a staff gage; a cell phone connected to an Internet modem; and a power supply.
“These stations collect stage, or the height of the water; temperature; pH; specific conductivity; turbidity; and dissolved oxygen every 15 minutes, 365 days a year,” he says.
The city has collected grab samples at each station for more than 15 years. It tests them for conventional parameters such as pH, temperature, dissolved oxygen, conductivity, and TSS, as well as for nutrient parameters such as total phosphorus and for metals such as zinc.
The city also has six weather stations in the area, which have an array of sensors that collect information for 36 separate parameters. These also collect data every five minutes, 365 days a year. These stations were installed as part of the city’s Water Conservation Program, but are also being used by the city’s Stormwater Program.
The continuous monitoring stations generate a large amount of time series data. At set intervals, typically daily, the data are downloaded as a flat file (.csv) and the raw data transferred into the Aquarius database. Since the advent of Aquarius 3.0, the city uses the Hot Folders feature to further automate the collection of the raw data and store them in the database.
“The great thing about Aquarius Workstation coupled with the Aquarius database is that it’s very useful for collecting, grading, doing QA/QC [quality assurance and quality control], processing, and storing meteorological, hydrological, and water-quality data for regulatory programs like NDPES and TMDLs,” says Gilbey.
Aquarius also makes it easy to correct for outliers from the remote sensors without losing the original data.
“Time series data typically contains many data points and, depending on the frequency of the data collection, can generate large files quickly,” he says. “Aquarius has the immediate ability to save and store raw data as well as make corrections. It provides the city with the ability to assess the representativeness of the data collected, based on our own criteria, and produce data of a known quality. That is very important. Anyone can put out a sensor, but the key is to collect representative data.”
Assessment. In the past, the city didn’t have time to do much analysis, but most agencies and EPA want to know what information the monitoring data is providing, Gilbey says. With Aquarius, collecting, grading, reporting, and storing time series data is made simple.
“Aquarius lets you pull the exact data you need from your database and perform most analyses very quickly and efficiently. For example, you can select data from the database, select a descriptive statistics toolbox, calculate medians and skewness, and with a few button clicks, it’s done. You can send the results from this analysis to a report template in the reporting toolbox, and you have your report. Next year we’ll be full-on reporting with Aquarius by developing a series of templates based on our monitoring plan in the reporting toolbox.”
Workstation allows Gilbey to easily compare and analyze data from the water-quality and weather monitoring stations as well as the water grab stations, either separately or in combination. He can develop rating curves that let him estimate flows at different elements of stage, which helps with the implementation and adaptive management of the city’s stormwater programs.
“For our stormwater permit, we need to demonstrate adaptive management and help direct where there may be a need for changes in our infrastructure, for example. When we implement LID [low-impact development], we assume through design that it will lower volume of runoff as well as treat the runoff, but when we collect the data, we can start to estimate the direct impacts of LID on the watershed,” he says.
Based on flow, turbidity, and TSS data, he can estimate changes in pollutant loading almost in real time if needed.
“TSS concentrations are a direct result of the urban flow regimes in our system,” he says. “High flows typically mean higher TSS as a result of bank erosion. Using Aquarius allows us to efficiently analyze and estimate TSS loads using our rating curves. Aquarius has the tools to efficiently collect, correct, grade, analyze, and store at a wide array of hydrologic parameters and make decisions about stormwater and watershed management based on real data.”
Aquarius also has helped the city detect and indentify illicit discharges into its waterways. Before it began using Aquarius, the city was unable to track the sources of illegal discharge because of the time it took to reach the site after being notified by residents. Aquarius has an automated notifications feature through its Springboard interface that sends an e-mail during high-turbidity events, which allows the city to quickly track the source of the illicit discharge.
Communication. Aquarius has helped with communication as well. Within the department, Springboard saves Gilbey time because he doesn’t have to download data for others to use. It also allows him to produce a much more effective annual report, which includes the city’s measurable goals, tracking measures, and analyses of their monitoring data, in much less time than before.
“The annual report includes the monitoring data that was collected as part of our permit compliance,” he says. “A report that typically took eight to 10 hours to complete can now be saved as a template and generated with latest year’s monitoring data already in the Aquarius Server in eight to 10 minutes.”
Aquarius also helps with the city’s education and outreach efforts because it is able to show real, local data to people, he says.
Gilbey is looking beyond meeting permit requirements with Aquarius. He uses it to talk to staff about capital improvement practices and engineering data. It also will help with the city’s master plan in the future.
“They’ve developed into a great system of tools to assist in watershed management,” he says. “Aquarius allows us to do a lot more with a lot less. The efficiency of being able to do it all in one place is amazing.”
Another software success story is the San Francisco Public Utilities’ use of GIS software from Esri, based in Redlands, CA, for its “Only Rain Down the Drain” program. This program began in early 2005 as part of the city’s stormwater management plan.
“One of the requirements of the stormwater management plan is public outreach and education, and another is the elimination of illicit discharge,” says Audie Ilejay, wastewater control inspector with the city. The goal of the program is to keep contaminants out of the stormwater system through outreach, inspection, and monitoring.
The program involves placing plastic curb markers that read “No Dumping: Only Rain Down the Drain” on approximately 23,000 catch basins and storm drains in the city’s densely populated 49 square miles. The markers include a phone number for residents to call to report clogged drains and illegal discharge.
“Our curb markers send a message,” says Ilejay. “We want to install them on all our curbs. Currently, we have covered 51% of the catch basins in the city.”
During the installation of the curb markers, San Francisco Public Utilities Commission (SFPUC) field crews inventory the catch basins, and there’s more to that than meets the eye. First, location coordinates are verified for mapped catch basins. Second, locations are added or modified to reflect catch basins that have been moved to comply with ADA regulations or road repairs.
One way to inventory the catch basins is to use GIS, says Lily Dryden, the enterprise GIS coordinator for the SFPUC. GIS gives the SFPUC the ability to see where the catch basins are, where markers need to be placed, and where they already have been placed.
“Our role here at Information Technology Services is to find solutions that meet more than one organization’s or division’s needs,” says Dryden. The needs of the approximately 2,200 SFPUC employees are varied. Esri’s solutions of Web-based, mobile, and desktop applications afford capabilities of working on multiple levels for sophisticated analysis projects and customization.
The curb marker program connects 21st century technology with San Francisco’s 19th century infrastructure. Some of the city’s sewer infrastructure dates back to the 1890s, says Ilejay; stormwater or street runoff and commercial, industrial, and sanitary wastewater flow into combined sewer system (CSS). More recently developed areas have separate systems for stormwater and wastewater.
The catch basins provide primary treatment for runoff, trapping heavy debris such as leaves and sticks. Pollutants including motor oil, grease, fertilizer, and pesticides are removed at one of the city’s treatment plants. This secondary treatment includes screening, sedimentation, and coagulation of floatables.
In 1992, the city redesigned the CSS to minimize flooding during storm events. “We built a series of transport and storage boxes below street level at various locations around the city,” says Ilejay. These concrete tunnels were built to contain stormwater runoff for a 10-year storm event, with capacity to hold approximately 197 million gallons. During heavy rainstorms, excess stormwater is diverted to the storage boxes. When the rains abate, the stormwater is pumped back to the treatment plant for treatment.
The Curb Marker Program. Although SFPUC has been using Esri solutions for years, this is the first time for fieldwork. For this project, Trimble GeoXH handhelds were selected for the mobile device, says Dryden.
Software includes Esri’s ArcPad to capture data, Trimble’s GPScorrect for ArcPad, and Trimble’s GPS Analyst extension for Esri’s ArcGIS desktop. The data collection forms and ArcPad toolbars were customized to simplify data capture.
Before the field crews head out into the field in the morning, the data steward uses ArcGIS desktop to define their work area for the day and loads the relevant data layers onto their handhelds. These layers include reference features such as street centerlines, parcel maps, and aerial imagery. Another layer allows crews to enter two street names and quickly zoom into a map.
Field crews verify and enter data on their handheld devices while they’re standing in front of the catch basins. If corrections are needed, they enter them into ArcPad. They also monitor the condition of the basins. If they’re damaged or need cleaning, this information is captured as well.
At the end of the day, the data steward processes the data. “GIS started as a way for us to inventory the curb markers,” says Ilejay, “but now we also use it to inspect and inventory the condition of the catch basins.” This helps manage workflow, and it also help crews repair and clean the catch basins quickly because current field conditions are known.
Asset Management Capabilities. The Sewer Operations of the Wastewater Collection division uses IBM’s Maximo for its work order management system, says Dryden. In September 2012, it implemented Maximo Spatial as the GIS component. This solution integrates Esri’s ArcGIS and Maximo to geospatially view service calls from the city and County of San Francisco’s 311 customer service and dispatch center, as well as for managing preventative maintenance work and assets.
When residents call to report illegal dumping or a clogged catch basin, a map displays their location by cross-referencing the asset, street address, or intersection so a maintenance crew can be dispatched quickly to the site. If there is a concentration of calls from a specific neighborhood reporting illegal discharge, SFPUC sends employees to the area with door hangers and flyers to educate residents about the importance of keeping pollutants out of the storm drains.
During storm watch events, the mapping capabilities will be invaluable, she says. SFPUC can quickly visualize areas of high service calls and enable them to deploy field personnel rapidly, therefore increasing responsiveness to their customers.
In the future, these applications also will help if there is a major toxic spill, says Ilejay.
“Based on GIS, we’ll know where to go and what part of the sewer lines we have to monitor.” It will be possible to trace the spill’s route to a treatment plant and warn personnel there before it arrives.