Water Quality Data – September 2016

Impacts of the drought include unusually high bacteria levels and dangerously low dissolved oxygen levels.

The Citizen’s Water Monitoring Network (CWMN) took place on Thursday, September 15. 41 sites throughout the watershed were sampled for water quality standards, testing for parameters including E. coli, nutrients, pH, and dissolved oxygen. The below map illustrates the bacteria results for the month, and you can also visit our water quality data page for more details.


Map of October 2016 CWMN Bacteria Results


Orange and red dots indicate sites where E. coli levels were above the swimmable and boatable standard of 235 (MPN/100mL). As has been the case all summer, bacteria levels were unusually high throughout the watershed, and this is likely due to the drought.

Five sites this month were exceedingly high for bacteria, with levels greater than 1000 (MPN/100mL): NER165, PEB008, PQB036, PTB035, PTB047.


Dissolved oxygen map of September 2016 results


Another water quality parameter that we test for is dissolved oxygen (DO), which is essential for fish to breathe underwater. Dissolved oxygen levels below 5 (mg/L) are dangerous for fish and other aquatic life and can result in their suffocation. The below map shows our DO results from September, with the red dots representing the “dangerous” dissolved oxygen levels. Twelve sites fell into this range, which is a much higher count than we usually get in September.

Similar to high bacteria, this is an unfortunate effect of the drought. Dissolved oxygen is influenced by temperature. When water levels are low, water is able to heat up faster and to higher temperatures, which in turn lowers the dissolved oxygen levels.

As of October 1, the watershed has been running an approximate 12 inch deficit of precipitation for the year in comparison to last year. Even though the watershed has received 3.93 inches of rain so far this month, it’s still not enough to bring us out of the deficit. Water conservation efforts remain vital!

As always, thank you to our unstoppable team of volunteers for getting up early to contribute to CWMN. If you are interested in volunteering, please contact Meghan at meghan@neponset.org.

Meghan Rauber
Field Sampling Coordinator
October 2016

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