Rosgen Stream Classification, or Rosgen’s index, is a system that classifies streams and rivers by morphology – patterns in the relationship between living organisms and their distinct structural features. Scientists and researchers apply the classification system to understand how streams have changed from their natural state, and what actions will be required for restoring stable stream channels.
Brenden Bixby, an Environmental Management and Fisheries and Wildlife Technology student, is in the Catskills this summer, examining the relationship between stream restoration in the Ashokan watershed and trout habitat. The work takes place in the streams that supply New York City its drinking water, and tests the effectiveness of applying Rosgen’s Trout index to Catskill streams. Geomorphological considerations – those exploring the relationship between streams and the landscapes surrounding them – are central to the research.
Assistant Professor of Environmental Science Dr. Andrew Gascho Landis has earned a Catskill Research Fellowship through the Cary Institute of Ecosystem Studies, allowing Bixby to complete the work. The project links resource managers with academic faculty, and the current research was developed in collaboration with Ulster County Soil and Water Conservation District, Cornell Cooperative Extension (CCE), and the U.S. Geological Survey (USGS). Addressing stream and watershed scale problems requires a team whose members bring a variety of expertise, from stream geomorphology, to fisheries, to habitat and riparian buffers.
Outcomes will benefit future stream restoration efforts by providing information on trout habitat, the effectiveness/ineffectiveness of riparian zones and canopy cover, and in-stream habitat.
Most importantly, the work will explore the relationship between all of these important factors.
Bixby is in the field three days a week. His responsibilities involve sampling – for invertebrates, sediment, and other aquatic vegetation – as well as using a laser level to develop longitudinal profiles to map streams. To chart stream channel shape, he is measuring stream cross-sections to determine elevation of flood events.
Brenden Bixby, seen here onsite in the Catskills.
The degree to which site surveying is involved is new for SUNY Cobleskill’s team members – both Bixby and Dr. Gascho Landis.
“There has been a learning curve for me,” says Bixby. “I had never used a laser level before. I had never used a McNeil core sampler (to measure sediment). I have had to take a lot of mental notes. But it has been a great way to absorb and take in this quality info.”
“It is great learning for me to see these stream assessment techniques in action,” says Dr. Gascho Landis. “Ulster (County Soil and Water) does this work, and we do more of the biota/habitat work – looking at downed trees, riparian zones, vegetation, canopy cover. It is a good blend of collaboration.”
Led by Dr. Gascho Landis, SUNY Cobleskill students performed similar work in 2018, along the eroding banks of Cobleskill Creek. The issue necessitating that endeavor stemmed from high-level flooding in Schoharie County; however, many of the restorative practices carryover into this summer’s project. Bixby and team will be looking at how well materials such as boulders and wood do in forming riparian zones, as well as fostering trout habitats.
Some sites the team has visited so far qualify as stable. For the purpose of this research, that means the stream has little erosion and stable banks (good channel access, or flow) and thriving, sustainable trout populations. Other sites need help in one or both of these areas. Still others have been/are in the process of being restored.
Stream restoration projects are typically conducted to help streams withstand flooding, often feature boulders. Boulders benefit trout by slowing the flow of water, helping juvenile trout maintain their position in the stream. Woody debris is another material commonly found in stable stream habitat. Insects rely on wood debris, — and insects are a major component of the stream trout diet.
That doesn’t mean all materials are created equal. Many of the restored sites the team has evaluated, including many that rely on boulders to withstand flooding, could include features that provide more benefit to aquatic organisms. Ideally, more restoration work could be completed using woody debris to provide fish and invertebrate habitat.
While boulders benefit juvenile trout populations in freshwater streams, woody debris, says Dr. Gascho Landis, fosters insect populations. Trout rely on these insects as a food source.
“Sometimes there are sites where it would be nice to see more wood built into the restoration,” says Dr. Gascho Landis. “That gives some consideration to a major habitat feature for these trout by providing refuge from high flows and supporting insect communities.”
The focus of the research is to secure evidence to support Dr. Gascho Landis’s hope: strong riparian buffers, coupled with healthy insect and trout habitats.
Bixby is a particularly good fit for this type of project. He is a fish enthusiast who says a big part of why he studies Environmental Management is because he doesn’t want to simply turn a hobby (for fish and fishing) into a job. He is spending his summer applying his major to his hobby, which just so happens to be his other SUNY Cobleskill program of study.
Maybe it is the other way around.
“Many times, this is like taking a full course in a day,” says Bixby. “The connection between our water sources, life, and the environment is really important to me. This is the kind of work I always want to be doing.”