May 2002 Monthly Report
by Roger Frymire

The focus of this year's effort, and the bulk of all remaining water chestnuts in the watershed, is Blacks Nook: a pond just off Concord Avenue
on the north side of Fresh Pond Reservation in Cambridge.

Harvests began on May 15 once plants began to reach the surface. So far, eleven days of harvesting have occurred there, two of those with Parth Patwari assisting. Amounts were counted and weighed the first two days to provide guidelines for estimating totals.

Over 1,200 pounds and 23,000 plants have been removed so far. Although the infestation covers a smaller area than that harvested in Blair Pond last year, a much greater density of the plants led to a LARGE underestimate of the amount of water chestnuts in Blacks Nook. In the densest areas, plants are packed closely with thirty to fifty plants in a square foot! I now estimate that this pond will produce over a hundred thousand plants this year, which would weigh at least three tons.

Water Chestnuts resettle in their new home,
the bottom of a recycling bin.

This is SIX times as much as I was expecting, so I am unsure whether this pond will be fully harvested in this first year.

I recently changed tactics here to focus half of each day on elimination of smaller infestations scattered about the pond. The rest I spend slowly reducing the size of the core infestation which now covers about 1/3 of the pond along the center of the South side. Although my permits for this project expire after this year, the Cambridge Water Department is willing to include these harvests in a comprehensive invasives removal permit they plan to take to the Cambridge Conservation Commission this fall, so I will have the time needed to finish this last hotspot in the watershed.

The only other part of the Alewife Watershed I have begun so far this year is Blair Pond. There appears to be quite good news here! Last year almost 32,000 plants weighing +700 pounds was removed to completely clear this pond for the first time. In two hours on May 25th, I cleared the pond completely -- removing 500 plants weighing only five pounds. A few plants remain on mudflats which I can only reach with higher water levels immediately following a rain, and murky water likely hides more plants not yet to the surface, but no great amount of time or effort should be required here.

The first two weeks of June, I plan to revisit Blair, as well as Yates and Spy Ponds. I expect to find very few plants at any of these locations. The
bulk of June will be spent continuing the attack on Blacks Nook. By the end of the month I should know whether a complete harvest will be possible there this year.

Early July, I will harvest the length of Alewife Brook, Little River, Perch Pond, and Little Pond. If there is another 90% drop from last year in these locations, only a handful of plants are expected! Hopefully at least Alewife Brook and Little Pond will remain completely free from Water Chestnuts as they were last year.

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