Water watch: Swimming advisories issued on Winni, Wentworth

There was one fecal bacteria advisory on Lake Winnipesaukee and one on Lake Wentworth, as well as a cyanobacteria report on Lake Winnisquam on Thursday morning, as residents and visitors to the Lakes Region geared up for another warm weekend.

Winnipesaukee

New Hampshire Department of Environmental Services staff issued a fecal bacteria advisory for Ellacoya State Park at the RV beach in Gilford on July 16, following sampling there the day before. Results indicated the presence of fecal bacteria to the tune of 172.2 parts per 100mL, well above the state standard of 88 parts per 100 mL.

Resampling was scheduled for July 17, with results expected to be available on Friday, July 18.

It’s the first time in July a fecal bacteria advisory was issued by the state at that beach, but not the first occurrence of the season: an advisory was in effect June 25-27. An advisory does not close the beach, it’s meant to warn the public regarding potential risks of recreation. When an advisory is issued, NHDES staff recommend not swimming or wading into impacted waters. 

To stay up-to-date on water quality all weekend, use the NHDES Healthy Swimming Mapper at des.nh.gov/water/healthy-swimming/healthy-swimming-mapper. 

Water samples are taken along the beach during routine inspections — NHDES staff sample Ellacoya State Park twice each month — and analyzed for the presence of E. coli. Results are generally available within 24 hours of collection. If two sample results from any one beach indicate E. coli presence above 88 parts per 100 mL or one sample above 158 parts per 100 mL, NHDES leaders issue an advisory.

Wentworth

At Lake Wentworth State Park Beach in Wolfeboro, a fecal bacteria advisory issued on July 9 was still in effect on Thursday. That beach was most recently sampled on July 14, and results indicated the presence of E. coli far beyond the state standard in three locations.

Resampling there occurred Wednesday, with results expected as early as Thursday. It’s the second fecal bacteria advisory issued at Lake Wentworth State Park, the first was between June 10 and June 18.

Winnisquam

And a member of the public observed and reported a cyanobacteria bloom on Lake Winnisquam on July 15 while boating, according to NHDES staff, which noted it’s a specific cyanobacteria bloom location, and more blooms could be present in other areas of the lake.

Bloom material can quickly move around a waterbody based on wind, wave and boat action, according to NHDES. Avoiding contact with areas experiencing blooms and keeping children and pets out of affected waters is recommended. 

The observer described the material as appearing heavier deeper down in the water column, resembling a snow globe.

Sampling conducted on July 15 there indicated the presence of 20,000 cells per mL, much lower than the state standard which triggers, when breached, NHDES staff to issue a cyanobacteria watch. 

A watch may be issued based only on a photograph of a suspected bloom, when the cyanobacteria density is approaching 70,000 cells per mL, when only one sample exceeds 70,000 cells per mL, or if the bloom material has passed. A cyanobacteria warning is issued when samples exceed 70,000 cells per mL at multiple locations.