Mystic Daily Boating Advisory

How safe is it to boat today?

These estimates of water quality conditions are generated by an automated bacteria prediction model and by additional cyanobacteria testing during boating season.  For more on what the estimates mean and how they are arrived at, see the questions below.

Mystic River

Mystic Valley Parkway (Rt 16)


Malden River

Revere Beach Parkway (Rt 16)


Upper Mystic Lake

Shannon Beach


What do the categories mean?


Boating is probably safe! The chances that E. coli bacteria levels exceed state recreational standards are low, and there is no evidence of a cyanobacteria bloom.


The chances that E. coli bacteria levels exceed state recreational standards are high, or there is evidence of a cyanobacteria bloom with concentrations exceeding state safety guidelines.


There is no evidence of elevated bacteria levels, but screening values indicate a possible cyanobacteria bloom.

Not Available

Current predictions are not currently available due to missing data or other system error.

How does it work?

Whether you’re rowing, kayaking or swimming, we want users of the Mystic to be able to make informed decisions about their activity. The Recreational Risk Assessment Project is all about communicating water quality conditions in a way that’s easily understood.  

In the first stage of this project, we collected and analyzed water quality samples for bacteria (Enterococcus or Escherichia Coli) and other parameters.  80 bacteria samples were collected from each of six sites between April and September in 2015 and 2016. We then used this data, along with additional bacteria data from the municipalities and the state, to develop models to predict water quality conditions in four areas of high recreational use. The models use real-time precipitation data and other variables to generate twice-daily predictions of conditions.

We share these predictions with the public in a few ways:

  • via a Twitter feed @SafeMystic
  • On electronic signs at key locations
  • And on this webpage!

What causes these health risks?




  • Dr. Jeffrey Walker (Walker Environmental Research LLC), Model and Website Developer
  • Dr. Nathan Sanders, Project Statistician & Mystic River Watershed Association Policy Committee Co-Chair

This project is funded by Massachusetts Environmental Trust.