It’s here! Yes we’re talking about the weather, as it seems that we’ve finally shaken off winter with some halcyon spring days. But we’re also celebrating the release of CRWA’s The 2017 Charles River Annual Water Quality Report! Since 1995, CRWA's Volunteer Monthly Monitoring Program has used a corps of over 75 volunteer citizen scientists to collect water samples from 35 sites along the Charles and its tributaries once each month and deliver them to us. We deliver these samples to Massachusetts Water Resource Authority (MWRA) to test for various pollutants and then analyze the results that they send back. We post the E. coli results every month, and while this can provide a quick way to gauge the cleanliness of the river on those days, it is only part of the story. The annual water quality report details results from all the parameters we measure in addition to E. coli: Nitrogen, Phosphorous, chlorophyll-a, Enterococcus bacteria, temperature, depth, and macroinvertebrate biodiversity and abundance. Analyzing all of these parameters across the whole year provides a broader perspective and a more general picture of the Charles River ecosystem’s health.
This year saw nutrient and bacterial pollution remain the most significant water quality issues in the Charles River, especially in the Lower Basin downstream of the Watertown Dam. There, while occurrences of excessive bacterial concentrations are much less common than twenty five years ago, they remain stubbornly similar to those from ten years ago. Throughout the whole watershed, nutrient (Nitrogen and Phosphorous) and bacterial pollution increased immediately after rain events. Most likely this finding results from increases in stormwater runoff across impermeable surfaces such as pavement, and outdated sewer infrastructures that lead to combined sewage overflows (CSOs) into the river.
You can find the whole document, download it, and read it all for yourself below. Thank you to MWRA and all of our volunteers for the work you put in that makes this project work so well.