The Watershed Alliance of Sandy Springs and eight volunteers, including three students, gathered Sunday afternoon, December 3, to clean up the unnamed creek that runs through Ridgeview Park (essentially “Ridgeview Creek”). Also the site of the fall 2016 clean-up, this time they found nine large bags’ worth of trash, as well as two rusted barrel drums. By far the most interesting finds of the day, reported Sherry Epstein, president of WASS, were the places where two drainage pipes from GA-400 empty into the creek.
WASS, which organizes two creek clean-ups annually, cleaned the stream in October 2016. Then and now, volunteers found large volumes of styrofoam – from cups to trays to the smallest crumbled pieces – as well as great quantities of plastic (bottles, bags, and food packaging) and aluminum cans. After the October clean-up, the stream banks were left significantly cleaner. “Most of it washes down from upstream areas and GA-400 especially,” noted Epstein. “That’s why stormwater mitigation, anti-littering , and these clean-ups are so important.”
During this clean-up, the volunteers tracked litter and erosion upstream to two places where drainage pipes from GA-400 empty into the streamshed (the area where all water flows into a particular channel, or consistently flowing stream). Highways might have occasional litter clean-up services, in addition to signs posted warning motorists against throwing trash on the highway on penalty of fines, but most stormwater drains into pipes that spill directly off the roadway into wooded areas and streamsheds, carrying with it any loose debris and trash.
This is what volunteers discovered at the clean-up: Where the two pipes from GA-400 empty out, stormwater is carving great holes in the stream banks. The banks are steep and the stream bed, deep.When it rains, the creek flow rises rapidly and erodes the banks in a process known as scouring: Sediment and debris scrape the banks, washing away dirt and exposing tree roots. This undermines the stability of the banks and the trees, creating conditions for a repeating cycle where the watershed becomes increasingly vulnerable. As more stormwater rushes in, banks become steeper, roots become progressively exposed and trees tend to fall, and the stream channel becomes even deeper. Creek clean-ups are the most immediate and direct way that community members can impact and observe our local watershed.
UPDATE: The article has been updated to reflect that the stream was last cleaned as part of a WASS event, prior to this day, in Fall 2016.