Consultant's Biological Survey Report, 1986

LYCOTT ENVIRONMENTAL RESEARCH, INCORPORATED
SOUTHBRIDGE, MA 01550
617- 765-0101

BIOLOGICAL SURVEY REPORT
FOR
FOSTERS POND
ANDOVER, MA

PROPOSAL/CONTRACT NO.: W-490-86
DATE SUBMITTED: August 5, 1986

LYCOTT ENVIRONMENTAL RESEARCH, INC.
600 CHARLTON STREET
SOUTHBRIDGE, MASSACHUSETTS

Biological Survey Report for Fosters Pond, Andover, MA

A biological survey of Fosters Pond in Andover, Massachusetts was conducted by Dr. Alexander Duran of LYCOTT on August 1, 1986. LYCOTT's services were requested by Steven Fey of the Fosters Pond Lake Association. Mr. Fey accompanied Dr. Duran on the survey and pointed out areas of the lake where boating and swimming uses of the lake were impaired by weeds and/or microscopic algae.

Water quality and recreational use of the pond is currently severely impaired due to excessive weed growth and algal blooms. Generally speaking, weeds cover 75 to 100 percent of all cove areas of the lake except where the weeds have been recently harvested. The central portion of the lake, although generally free of nuisance weeds, is a pea-soup green color due to an algal bloom. The major nuisance weed species found in the lake include yellow and white water lilies, Cabomba sp., Elodea sp., Potamogeton sp. and Swamp Loosestrife. The distributions of these weeds is shown on the attached map. Swamp Loosestrife is a rooted emergent type of weed which forms dense thickets in the shallow water near the shores of the land and islands in Fosters Pond. Elodea sp. ("Water Weed") is a rooted submerged type, as is Cabomba sp. ("Fanwort"). Cabomba is a very fast growing weed and if left untreated can often take over the shallow portions of a lake and render it unfit for swimming or boating. This has occurred in the northern, narrow necked cove of Fosters Pond. Potamogeton sp. and yellow and white water lilies are rooted, floating leaved plants which interfere with swimming and render the pond aesthetically unattractive.

RECOMMENDATIONS

To improve the water quality of Fosters Pond, both short term and long term actions are indicated. In the immediate future, only chemical treatments will be effective in reducing weed and algae growth. In the long run, sources of nutrients, principally phosphorus, to the lake need to be controlled. A well regulated program of progressively larger lake drawdown will prove beneficial in enhancing the effectiveness of both short and long term strategies.

The class of compounds called "aquatic herbicides" are an effective non mechanical means of weed control. An herbicide can be applied to the whole lake or only to a well defined cove, for control of weeds lake wide, or within the cove, respectively. For control of algae, copper containing compounds (algecides) must be added to the entire lake. Since the lake has both algae and weeds, optimal treatment would include both herbicides and algecides. An alternative to algecides for algae control is to treat the entire pond with alum. This chemical precipitates all suspended solids, including algae, out of the lake water and also chemically binds the phosphorus, which algae grow on, and keeps it " locked" in the lake sediments. Without phosphorus there can be no algae blooms.