When accurately obtained and analyzed, water-quality data has the potential to drastically influence our daily lives by identifying problems, verifying solutions, and fueling scientific revelations. Understanding how water moves through our society and how our society affects its condition can improve conservation and management of this necessary global resource. Every day and all around the globe, scientists and everyday citizens participate in monitoring projects to advance their water resource understanding.
The diversity of monitoring projects rivals that of monitoring equipment, which offers a dazzling array of possible tools to measure flow rates, level, temperature, pH, and dissolved oxygen, or to screen for possible contaminants like mercury and fecal coliform. Should the sensors be ultrasonic, take automated readings, be portable, or take grab samples? Considerations include how data will be transferred for analysis, what maintenance the equipment requires, and if vandalism or animal tampering must be considered. Any project proposal requires careful thought and planning, particularly when researching and selecting appropriate and cost-effective equipment to employ.
The considerations seem endless, but fortunately plenty of scientists—like those in the following case studies—have previously deployed projects, learned from the experiences, and shared their insights.
Automated Loggers Verify Citizen Science
The 220-square-mile Kathmandu Valley seethes with humanity. Growing at 4% per year, its Nepali population of roughly three million people has consumed all desirable open land and joins the population density ranks of US cities like Chicago, Philadelphia, and Miami. As in these western cities, rapid urbanization and development of the basin has created a sea of hardscapes to intercept falling rain and has left few open spaces for groundwater infiltration. Further, the seemingly plentiful 55 inches of rain that falls each year comes primarily during a condensed monsoon season from June to September. “It’s really a timing issue,” says Jeff Davids, founder and president of Smartphones4Water (S4W), a US-based nonprofit organization. “When the monsoon comes for four months, there’s a ton of water, but during the other eight months all that water has run off. It’s gone [downstream] to India and the ocean.”
This collision of urbanization and climate causes water withdrawals to exceed replenishment. The nine tributaries that have replenished the valley’s Bagmati River for millennia now frequently run dry before contributing any flow. The dominant waterway no longer teems with fish and macroinvertebrates, instead serving more as a polluted, stagnant sanitary conveyance. Failing surface water supplies drive the population to rely more heavily on groundwater, while urbanization carries away almost all replenishing falling rain. Even capture and storage of monsoon rains presents problems. “There are very few suitable reservoir sites geologically stable enough to build an impoundment,” says Davids. “We’re also paving over all the potential recharge areas, so we’re decreasing our infiltration capacity.”
Although the water resource problems are painfully evident, a lack of accessible data exists to contextualize the severity or timing of depletions, or to serve as a basis for policy discussion or problem solving. That’s where Davids, Smartphones4Water, and a cadre of citizen scientists hope to be of service. Backed by collaboration with the Himalayan Biodiversity and Climate Change Center, Kathmandu Institute of Applied Sciences, Delft University of Technology, the Swedish International Development Agency, and Stockholm University, the S4W team recruits and trains local citizens to collect water-quantity data. Many of the valley’s residents do not have computers or internet access, but they do have smartphones, which can be quickly formatted to input rainfall, groundwater level, and river level observations.
“We just completed an initial campaign evaluating different approaches to citizen scientists taking water level observations,” says Davids. For roughly six months, a few local citizens collected daily observations of precipitation and of water levels in nearby streams. Each citizen scientist water level observation entails recording the date and time and the GPS coordinates, entering the value from a staff gauge, and taking a picture of the staff gauge (for validation of the citizen science entry) with a smartphone. At key locations, several Onset water level sensors, including the HOBO MX2001 Water Level Data Loggers, were installed to automatically record water level and temperature every 15 minutes.
The continuous water level data from the Onset sensors was then compared to the less frequent (e.g., daily) citizen science observations to document the reliability of citizen science for the measurements involved in the Nepal project. The S4W team also recently explored the impacts of lower-frequency water level observations on the accuracy of streamflow statistics like maximum flow, minimum flow, and runoff, as detailed in a paper titled “Continuity vs. the Crowd—Tradeoffs Between Continuous and Intermittent Citizen Hydrology Streamflow Observations,” recently published in Environmental Management.
The HOBO MX2001 can be wirelessly set up and data downloaded via Bluetooth Low Energy technology, which simplifies collection of field data. “What I like about that sensor is you use the smartphone’s telemetry,” says Davids. “Data downloads over Bluetooth, then you can walk away and send the file over your cell network whenever you have a connection.” Sensor configuration, operational status checks, graphical data views, and data download are all made possible by installing the HOBOmobile app on a mobile Apple or Android device, including smartphones and tablets. Starting at $600, the MX2001 offers several models with sensors of increasing water depth range that can be deployed in fresh or saltwater.
“I’ve used Onset equipment over the last 10 years, including hundreds of different data loggers, and I’ve loved working with their team,” says Davids. In addition to the HOBO MX2001, S4W has been using roughly 10 of Onset’s older non-Bluetooth water level sensors to help with data verification. The S4W team is also considering adding Onset tipping bucket rain gauges to their data collection portfolio for the coming monsoon season.
With the reliability of citizen scientists supported and measurement collection approach refined at the end of the six-month trial, the S4W team has started recruiting roughly 100 Kathmandu residents for further data collection across the entire basin during the monsoon. Thanks to donor funding, the S4W team compensates its citizen observers with 25 rupees (roughly $0.25 USD) per observation, per day—which in some cases can be 10% of their daily income. Most observers monitor a single location where they live, although a few have multiple locations.
To contribute observations, their smartphones are outfitted with a preformatted, Android-based data entry application called Open Data Kit, “an open-source suite of tools developed by University of Washington researchers that helps organizations author, field, and manage mobile data collection solutions” according to its website. Since 2009, ODK-powered digital forms have facilitated public and private projects around the globe including national election fraud prevention, documenting archaeologic site data, mapping soil conditions, and collecting socio-economic data on flood victims. A smartphone, equipped with ODK, camera, microphone, GPS, accelerometer, touch screen, and Wi-Fi capabilities, can suddenly become an invaluable, lightning-fast research tool even in untrained hands.
“The traditional [data collection] culture would be to download logger data to a computer and email or transfer data,” says Davids. “Using the smartphone to do that job is easier, lower maintenance, and cheaper.” But he recognizes collecting data is only the first step. “Collecting good data is necessary for understanding any problem, but just because we collect data doesn’t mean we’ve arrived at a solution.”
Davids doesn’t feel S4W and its data collection efforts will immediately reveal answers to Kathmandu’s water resource problems, but that the efforts help characterize the nature of those problems. “It brings a level of credibility. We’re trying to collect the vitals of the valley to see trends: how quickly groundwater is depleted, how quickly streams and springs dry up, and how climate change affects precipitation.”
Kathmandu’s water resource issues have needed a solution for many decades. Currently under construction, the 17-mile Melamchi River water supply tunnel will divert almost 45 million gallons of freshwater into the Kathmandu basin from an adjacent watershed. “The public opinion is that once the Melamchi water gets here, everything will be resolved and our rivers will be clean again,” says Davids. “It’s really oversold. Because it was designed in the 1980s, it appears to be undersized and doesn’t meet the current demand, so it’s already behind.” Perhaps realizing this shortage, the Melamchi Water Supply Project website mentions ongoing investigations into diverting an additional 45 million gallons from the Yangri and Larke Rivers.
Davids also mentions that supporters of the Nepali project can contribute by donating their used smartphones. Although most Nepalis have their own, S4W occasionally supplies them to the most remote and underprivileged of their citizen scientists. “We’ll ship unlocked Androids with a working GPS and camera directly to Nepal,” says Davids. “If it’s not an appropriate phone, we send it to a US recycler and use the proceeds for project funding.”
Improving the Saint Lawrence River One Beer at a Time
As if the craft breweries popping up in local neighborhoods like hop vines in springtime wasn’t enough evidence, the Brewers Association recently released 2016 data indicating that craft breweries continue to be a skyrocketing industry segment. In the US alone, 5,200 craft brewers produced 24.6 million barrels, each requiring an average of five freshwater barrels to produce. At 31 gallons per barrel, that means US craft breweries consumed 3.8 billion gallons of freshwater to produce roughly 763 million gallons of beer, leaving roughly 3 billion gallons of wastewater for treatment and discharge. By contrast, Canadian craft breweries consume even more freshwater, averaging five to eight barrels per single barrel of beer.
To help breweries in their region become better water stewards and make informed decisions about wastewater treatment, the Saint Lawrence River Institute of Environmental Sciences, based in Cornwall, ON, aims to develop monitoring systems to quantify wastewater volumes and the byproducts it contains as the brewing process unfolds. “When you know how much water you’re using and what is in it, then you can consider what to do with it,” says Louis Savard, program leader of the institute’s River Labs division. He and institute colleagues have been working in conjunction with Michael Fagan, senior vice president at BLOOM, another Ontario-based not-for-profit organization that has been working with craft breweries to improve their water management practices. BLOOM has been working with Ontario Craft Breweries over the past years and they have developed a website called Water & Beer (waterandbeer.bloomcentre.com) to consolidate key “why, what, and how” insights.
Institute staff initially investigated a few monitoring options, considering sensors both internal and external to the transfer system. “There are mechanical flow meters that can be installed inline in the transfer pipe, but brewery water varies from 20 degrees Celsius (68 degrees Fahrenheit) to boiling, a pH from 3 to 13, and chock full of sugars,” says Savard. “The filters on mechanical flow meters would clog and stop working very quickly. They’re just not built for that abuse.” Instead, institute staff opted to install Greyline Instrument’s Transit Time Flow Meters on the outside of the pipes.
By transmitting 1 to 2 MHz ultrasonic pulses from one transducer, the flow meters record the time it takes the signal to travel across the pipe interior, bounce off the opposing interior wall, and to be received by a second transducer positioned on the same exterior side. Signals are transmitted both directions between transducers, permitting comparison of upstream and downstream time measurements and determination of flow rate and volume. Greyline recommends its three transit time models, PTFM, PT400, and PT500, for monitoring of clean fluids virtually devoid of air bubbles or solids, such as water, water and glycol solutions, oils, and most chemicals.
“We wanted to see if transit time meters could be used on smaller-diameter stainless steel pipes to quantify the volume of water coming through the different processes: mashing, boiling, fermenting, clarifying, and packaging,” says Savard. He and the institute team knew there might be obstacles within the brewery setting. “The sensors are very [motion] sensitive,” says Savard. “Any vibrations will potentially throw off readings.” He also notes that the stop-and-go nature of brewing can pose difficulties for sensor operations. “The meters are built for constant-flow, constant-filled pipes,” he says. “That’s why we wanted to test meters and see what challenges we had.”
During meter testing, institute staff manually collected wastewater samples for lab analysis of pH, biochemical oxygen demand, chemical oxygen demand (COD), and nutrient contents to quantify water quality at different transit points. “That’s another area we’re looking into to see if there’s available technologies to monitor those in real time,” says Savard, referring to their initial experiment with MANTECH’s PeCOD Analyzer, capable of measuring chemical oxygen demand in approximately 15 minutes. Instead of using traditional hazardous reagents in
a laboratory setting, the onsite peCOD measures the photocurrent charge emitted by oxidizing organic species within a sample.
The electrochemical potential of the peCOD’s UV-activated nanoparticle titanium dioxide photocatalyst far surpasses that of typical dichromate testing, making it an extremely effective oxidizer and more accurate for a broad range of organics. MANTECH recommends the PeCOD COD analyzer for use in both wastewater and drinking water applications. The institute will compare traditional lab results obtained from the grab samples with the PeCOD real-time results to evaluate efficacy and be able to offer informed recommendations to brewery operators.
Savard and the institute plan to continue brewery experiments this year, trialing additional monitoring equipment and comparing results. “We’re going to take it a bit further this year and use different technologies from Greyline,” says Savard. For instance, the Transit Time Flow Meter will be replaced by Greyline Instruments’ Doppler Flow Meter, which similarly calculates pipe flow by transmitting high-frequency sound (640 kHz) emitted from the meter positioned on the external pipe surface. Instead of observing the transit time of sound pulses, the meter transmits continuously and measures any shifts in frequency of returning echoes that bounce off solids or bubbles in the flowing liquid. As liquid moves, the echo frequencies shift in proportion to flow velocity.
The Doppler Flow Meter may be better suited to brewery fluid transits because it specifically measures dirty or aerated liquids externally. Greyline suggests the Doppler works with “difficult” liquids including slurries, sludges, and corrosive chemicals that would normally damage internal flow meters. “Breweries, being stop-and-go operations, experience frequent pulses and loading becomes a bigger issue. If they’re sending out low-strength, high-volume wastewater, it’s not as much of a concern as a low volume of super-high-strength wastewater.” He hopes the institute’s experiments will improve both water use and wastewater handling within brewery settings, along with refinement of monitoring equipment better suited to the brewery industry.
Evaluating Drywell Recharge in the Los Angeles Basin
According to the US Geological Survey, groundwater supplies almost 40% of consumption by four million people residing in California’s Central and West Coast basins. Although the abundance of precipitation during the recent winter season has brought surplus water to these regions and either extinguished or lessened the drought conditions, the groundwater can’t recover so easily. Moving on a geologic time scale and impeded by alterations like paving and construction within potential recharge areas, groundwater continues to be an ever-shrinking resource.
In the city of Los Angeles, the Department of Water and Power partnered with the Department of Public Works to undertake a drywell project at the foot of the San Gabriel mountains to investigate the feasibility of restoring the link between precipitation and groundwater recharge. “Drywell systems are effective at getting water into the ground,” says Eric Noreen, engineering geologist associate with Los Angeles’ Department of Public Works. “The City wants to capture as much runoff as possible and save every possible drop of water.”
The development intensity within the greater Los Angeles basin means few groundwater recharge areas remain for installation of additional spreading basins, a traditional recharge method of drawing water into a shallow impoundment with a large surface area and high-infiltration soils. Over time, the water percolates back into the water table below. “Unfortunately, there’s a limited amount of land left for spreading centers,” says Noreen.
Needing creative, compact options specifically designed to capture urban runoff, a pilot project of 45 drywells was installed in the San Fernando Valley’s Pacoima neighborhood, an approximately 80% residential area, to test their effectiveness. Each drywell has three components: an inlet catch basin, a settlement chamber, and an infiltration chamber with injection well. Runoff collected from the streetscape funnels into the catch basin as in a traditional stormwater collection system. However, the flow then diverts by pipe connection into a 10-foot-deep settlement chamber to trap any debris, leaves, and sediment before sending the flow through a second pipe connection to the injection chamber. There, the water fills the chamber before flowing into a perforated PVC gravel-packed infiltration pipe that extends into the subgrade below.
“My primary interests were researching how fast water was getting into the ground and evaluating the overall design,” says Noreen, who installed two types of monitoring sensors to collect water level observations in the three chamber components. At four drywell locations, he placed a water level sensor in the settlement chamber and two sensors in the injection chamber—one in the upper collection chamber and one in the bottom of the infiltration pipe. At an additional nine drywells, Noreen placed water level sensors in only the injection chamber and infiltration pipe. At each drywell monitoring location, all sensor transmitters were located within the catch basin for easy street-level telemetry.
Sensor locations were spread across the project area to represent varied conditions, with a few placed in adjacent drywells to also evaluate effectiveness of drywell spacing—whether there were too many or too few in each area. Additionally, to aid real-time monitoring during storm events, one drywell system received three In-Situ Rugged TROLL 200 Data Loggers equipped with Tube real-time cellular data transmission capability to track water level, pressure, and temperature. When a storm event occurred, the system texted an alarm to Noreen, facilitating his real-time observation of data as runoff collected and moved through the drywell. “When the water level reached a foot above the sensor, I’d receive a text message that the storm was happening, and I’ve been able to monitor the rain events immediately,” he says.
With remote telemetry staged from a separate manifold box outside the drywell system, the In-Situ sensors ran smoothly for the duration of Noreen’s observation project. The other sensors, with more traditional onsite telemetry, experienced collective losses of roughly 20% over the two-season monitoring project, as water levels sometimes exceeded their staging site within the catch basins. Some of the drywells happen to be in flood-prone areas. By installing a series of drywells in such areas, the city’s Department of Public Works hopes to eliminate flood events and prevent future road shutdowns.
Noreen views the monitoring project as a success. “I was able to evaluate how well they functioned individually and how they functioned as a group,” he says. Because there were multiple locations of drywells installed in series, Noreen collected solid data on their larger performance as a series. “Multiple sensors show the water was dropping off,” he says. “Maybe the first drywell was overwhelmed, but the second or third levels dropped off, so I was able to look at flow patterns in these areas.”
Overall, he determined that both the individual drywell system and the collective drywell network was overdesigned. “Monitoring gave me evidentiary backup to make my claims,” says Noreen. “Now the data is there to provide information for future design.” Because the City hopes to install thousands of dry wells over the coming years, Noreen thinks the data will help get the water into the ground as quickly and cheaply as possible. “More pathways for getting the water into the ground need to be developed, because we could lose the capacity of the aquifer.” Should additional monitoring happen in the future, he would hope to employ sensors to further refine the design and siting of drywells.
Noreen expects that the drywells will require minimal maintenance for up to 10 years, aside from periodic trash and sediment removal by vacuum truck. Eventually at each drywell, fine particles unable to be trapped by the settlement chamber and filter system will choke the infiltration chamber and well. At that time, they’ll be converted to serve as settlement chambers for new infiltration components constructed adjacent to the original installations. In this manner, infiltration can continue indefinitely.
Advancing the Monitoring Science
Just like the S4W and Saint Lawrence River Institute of Environmental Sciences teams, those monitoring and studying water resource issues learn from their experiments and adapt their next round of studies. In Nepal, S4W attempts to understand large-scale water dynamics within a large basin receiving seasonal rains and so opted for inexpensive equipment requiring minimal maintenance with limited vandalism and theft risk. On the other hand, examination of brewery wastewater by the institute staff requires a more accurate, detailed analysis on a significantly smaller scale. These demands require more costly equipment capable of fine measurements.
Each team adapted its strategy and tools to match project end goals, but both recognize that immediate results do not necessarily precipitate an immediate change. The information collected informs and expands current understanding, setting the scene for initial discussions and decision making within the team and, if unveiled to the public, within policy circles. Davids hopes that at some future point if S4W concludes its work in Nepal, the data collection will continue. “In a perfect world, it would continue as a grassroots project and build an open-source database that would grow over time and move out into other regions,” he says.
Similarly, Savard and the institute hope all of their research projects advance scientific understanding and environmental stewardship, not just within the brewing industry. “Research is lost if you don’t share it, so we have a very strong outreach component to engage the community and organizations to collaborate and share information, provide workshops and public seminars,” he says. “It’s important for us to share.”