June 15, 2016
Unquity Brook is one of the hotspot streams that has been identified as an area that has chronic pollution issues and needs to be addressed immediately. Water quality data collected by our CWMN volunteers have documented the long history of pathogen and nutrient pollution issues that the brook has suffered.
Unquity Brook holds a special importance in our watershed because it is provides spawning grounds for the migratory Rainbow Smelt. The once common Smelt, have been in decline over the past decades because of over fishing and loss of spawning habitat.
Recognizing the need for urgent action, NepRWA partnered with the town of Milton to secure funding through the Department of Coastal Zone Management to closely monitor water quality within the stream and to find locations within the watershed where stormwater management devices could be used to improve water quality by reducing the negative impact of stormwater runoff.
Past efforts to address the water quality issues in Unquity Brook have failed mainly because they were unable to locate where the contamination was coming from. This spring, with the help of a newly developed technology called “Microbial Source Tracking,” we were able to locate two major points of sewage contamination, and we are now one step closer to resolving the pathogen problem within the brook.
Over the course of this project we conducted 3 rounds of sampling (2 during dry weather, and 1 during wet weather), surveyed 14 potential stormwater runoff treatment sites, and developed conceptual designs for the top 3 sites. After sampling, we held a meeting with the Milton DPW to present our water quality data and to discuss our ideas for potential stormwater management improvements.
Water Quality Data
The water quality data from our sampling missions suggested that there are two major points of sewage contamination along Unquity Brook. Once notified of the two trouble areas, Milton DPW was able to develop a short list of likely sources of contamination. One of the sites is a municipally owned building that has suffered from chronic sewage backup in its basement. The other site is less obvious. Further tracking within the stormwater infrastructure by town staff will be needed to locate the sources of the sewage pollution and ultimately fix the problem. While the grant funding for this project ends June 30th, we will continue to work with the Town of Milton to resolve the identified issues, and will provide updates on the progress.
Stormwater Management Improvements
After a long discussion with Milton DPW about proposed stormwater management sites, we were able to reach an agreement on the top three sites: the Milton Police Station, Cunningham Elementary School, and the intersection of Brook Road and Centre Street. We are now in the process of writing a follow-up grant to hire an engineering consultant to develop detailed plans that could be used to implement these projects in the future. If all three projects were implemented, runoff generated from an estimated 1,049,455 ft² of impervious surfaces would be treated before reaching Unquity Brook.
The combination of improved stormwater management and eliminated sewage contamination will lead to massive improvements in the brook’s water quality, and to the restoration of the prized Smelt breeding grounds.
For more information about the project, contact Chris Hirsch at Hirsch@neponset.org