Summary
CRWA
conducted water quality monitoring on Cheesecake Brook on three occasions: 1)
November 29, 2006 – a dry weather
monitoring event, 2) May 9, 2007 – a dry weather monitoring event
and 3) June 4, 2007 – a wet weather monitoring event.
Samples
were collected at ten sites along Cheesecake Brook.
Click here for a site
map. Samples were analyzed for
several pollutants of most concern in the watershed: E. coli bacteria, total suspended solids, and total phosphorus. CRWA also measured several in
situ parameters including pH, dissolved oxygen, specific conductivity
and water temperature.
E.
coli levels in many locations during all monitoring events
exceeded the State surface water quality criteria for swimming, 126 cfu/100mL.
The wet weather E. coli levels greatly exceeded the boating limit of
630 cfu/100mL, peaking at 71,000cfu/100mL. However, only a few of the dry
weather events exceeded the criteria for boating.
During the two dry weather events in November and May, bacteria
concentrations ranged from 10 to 2,000 cfu/100mL. In contrast, the wet weather levels
in June ranged from 18,000 to 71,000 cfu/100mL. Click
here
for the water quality results tables.
During the June storm event,
the extremely high levels of bacteria
(18,000 - 71,000 cfu/100mL) may be indicative of sanitary sewage
discharging to the stormwater drainage system through Newton's underdrain system
and of polluted stormwater runoff. The elevated total suspended
solids (TSS) concentrations during wet weather, which were as high as 256
mg/L,
exceeded CRWA's action limit of 30 mg/L. The total phosphorus levels
were also higher than dry weather, ranging
from 0.22 to 0.57 mg/L and exceeding the 0.024 mg/L limit (US EPA’s recommended
total phosphorus criteria in our ecoregion). These
results show how the water quality of
the river is impaired during wet weather by stormwater runoff and illicit
discharges.
See
sampling
map ,
sampling site descriptions , Cheesecake
Brook photos , and
water quality monitoring
results for further information about Cheesecake Brook.
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WATERSHED INFO
