DEEP Staff Pioneer Innovative Method to Monitor Stream Connectivity
Staff successfully deploy trail cameras to monitor stream levels, proving cost-effective method that will help inform stream management efforts.
For all living organisms on Earth, the presence of water means life, and the absence of it means death. That’s especially true for organisms that spend their entire lives in water.
For many fish species, like the brook trout, a healthy stream provides the setting for the full range of its life activity- shelter, food, and reproduction. They require the whole stream to provide the right setting for each activity, from deep slower-moving pools, to shallow, fast-moving “riffles,” and for there to be enough water in the stream to connect all of these habitats. When a stream becomes too dry, the habitats shrink and become disconnected. Fish might not be able to perform critical life functions and will die or fail to reproduce. The cause of the low water levels can be man-made interventions such as dams or water withdrawals, or natural phenomena such as the significant drought we are currently experiencing.
Stream connectivity during droughts is one of many concerns for staff in the Connecticut Department of Energy and Environmental Protection (DEEP)’s Water Planning and Management Division. When a stream is completely dry, the impact is obvious, but in areas where there is some flow but not as much as should be there, the impacts become harder to quantify. One way the United States Geological Survey measures streamflow discharge is through operating gaging stations that cost approximately $20,000–$25,000 to install with an annual operation and maintenance cost of $15,000.
Because of the limited network of these gaging stations, DEEP staff came up with an interesting (and less expensive) workaround in 2017—from July to October, at a cost of roughly $500 per unit, they deployed digital “trail” cameras at seven “study” streams around the state, and set them to take a photo every hour. The photos were saved to a memory card, and collected by staff every 3-5 weeks.
The images were then evaluated and placed into one of six categories of connectivity established by staff, who were trained in order to standardize image interpretation. Categories 1-3 represent streams at different levels of disconnected flow, with Category One being completely dry. Categories 4-6 represent streams at different levels of connected flow, with Category Six representing healthy flows above “bankfull” discharge. From these images, staff were able to calculate an average daily stream connectivity category for each study stream. Using these categories, staff also developed 30 metrics to describe the magnitude, frequency, duration and timing components of stream connectivity.
Believing that the methodology they’d established was so innovative, thorough, and most importantly, proven, staff sought publication of their method in hopes that it might prove useful to others working in the field of stream management. After more than a year of effort that included an extensive, rigorous peer-review, the paper was published in August in the journal “Rivers Research and Applications.”
Staff involved in the creation of the method call it a significant, and potentially game-changing tool to help inform approaches to stream management.
“It’s a method that allows us to begin to identify the issues,” Corinne Fitting, a Supervising Environmental Analyst with DEEP, and one of the paper’s co-authors, said. “Once you’ve documented impact, the next steps are to figure out why and how we can deal with it, but the first step is saying ‘there’s a problem here,’ and the trail cameras are allowing us to do that.”
Philip Trowbridge, Assistant Director of DEEP’s Water Planning and Management Division, said that having a process to objectively identify areas where there isn’t enough water and streams are going dry will better inform planning documents such as the State Water Plan and decisions about managing water balances. Trowbridge said that of the three main stressors that contribute to stream impairment—nutrients, urban run-off, and flow—flow had been the most challenging for DEEP staff to gauge prior to establishing the new monitoring method.
“I’d say this was a gamechanger in our ability to investigate and follow up on localized issues for one of our major stressors,” he said.
Christopher Bellucci, the primary author of the paper, noted that the method has enabled staff to add—backed up by objective reasoning—several miles of streams to the state’s “Impaired Waters List,” a list that is updated by DEEP and approved by the U.S. Environmental Protection Agency every two years as required under the Clean Water Act.
“We’ve increased the miles that we attribute as flow-impaired substantially in part because of this method, and now we can feel fairly confident that yes, we have evidence, we have metrics that we’ve calculated,” he said.
Bellucci, along with paper co-authors Melissa Czarnowski and Mary Becker, have shared the method with peers at science conferences over the last several months, and some states, including Vermont, have adopted aspects of the method for their own research. At DEEP, staff continue to employ the new methodology. Currently, staff have about 30 trail cameras deployed, capturing photos every hour of every day. Given the considerable time investment required to process this data (the cameras have captured some 60,000 photos this year alone), staff are continuing to innovate by experimenting with machine learning techniques, training computers to review photos and categorize them.
Staff are excited for the continued possibilities this method and this type of data capturing allow. From continued documenting of stream connectivity, to monitoring ice cover on lakes, to counting anglers at remote fishing areas.
Water is critically important, whether you’re a brook trout trying to perform your basic life activities, or a human in need of water to drink, to shower with, cook with, do laundry with, wash your hands with during a pandemic, or to help put out a forest fire. Understanding this, DEEP encourages you to Imagine a Day Without Water, a national education campaign that highlights how water is essential, invaluable, and in need of investment. This year’s day of action and awareness takes place on October 21, 2020, and will include events, resolutions, student contests, social media engagement, and more, across the country. Unfortunately, the ongoing drought makes imagining a day without water easy to do this year.
See attached photos, which depict examples of the six different stream connectivity categories:
Category 1 (completely dry), taken at the Mill River in Cheshire, 9/25/20 (This stream was not included in the method paper as one of the study streams, but is being shown here for reference. None of the study streams were Category 1).
Categories 2-6, were taken on different dates at Pendleton Hill Brook in North Stonington, which was one of the study streams:
Category 2: 8/27/2020
Category 3: 7/15/2020
Category 4: 6/10/2020
Category 5: 6/30/2020
Category 6: 4/27/2019
More at: portal.ct.gov/deep| Follow on Facebook at CTDEEP| Follow on Twitter @CTDEEPNews