The following data is downloaded from the MA EEA Data Portal for CSOs. Data in the portal extends backwards to mid-2022. The portal has data on release volumes from specific CSO outfalls by date. Precipitation data is acquired from USGS gage at Fresh Pond, near Alewife Brook.

Totals for Mystic River and Alewife Brook CSOs

OutfallId WaterBody 2023 2022 2024
BOS017 MYSTIC RIVER 601,000 NA NA
BOS019 LITTLE MYSTIC CHANNEL 1,163,000 71,500 NA
CAM001 ALEWIFE BROOK 10,000 NA NA
CAM401A ALEWIFE BROOK 18,472,000 450,000 NA
CAM401B ALEWIFE BROOK 1,010,000 NA NA
CHE003 MYSTIC RIVER 28,000 NA NA
CHE004 MYSTIC RIVER 58,984 NA 10,955
MWR205 MYSTIC RIVER 130,580,000 15,080,000 NA
SOM001A ALEWIFE BROOK 7,019,000 32,000 NA
SOM007A/MWR205A MYSTIC RIVER 43,560,000 2,720,000 NA

CAM401 is responsible for the majority of releases in Alewife Brook.

2023 Summer - Fall Alewife CSOs by Outfall and Date

SOM001A releases only on days on which there is also a release at CAM401A. CAM401A consistently has greater volumes than SOM001A.

Precipitation and CSO volumes

Precipitation rate (right hand column) is a better predictor of CSO volumes than total daily precipitation (left).