Flannagan Pond
Flannagan Pond
(aka Fletcher's Pond, Flanagan's Pond, Lower Flannagan Pond)
- 87 acres
- A shallow pond with a maximum depth up to approximately 5 feet and average depth of 3 feet
- Artificially created by the impoundment of water via the East Main Street Spillway (aka Balch Dam), located off Central Avenue and near the Rotary, hence a ‘flooded wet meadow’
- Perimeter 2.7 miles
- Part of the 538 square mile Nashua River Watershed
- Located within the Petapawag ACEC (Area of Critical Environmental Concern)
- Receives its water from Sandy Pond at inlet at eastern end (via culvert underneath Snake Hill Road), and from Pine Meadow Pond at northwestern end (via culvert underneath Oak Ridge Drive)
- Water flows from Flannagan Pond at southwestern end through culvert under Central Avenue into Balch Pond
- A flooded wet meadow created by the impoundment of water via the East Main Street Spillway (aka Balch Dam), located off Central Avenue and near the Rotary
And if you want to learn more…
General Description and History
Flannagan Pond is part of the chain of hydrologically-connected ponds and streams that bisect Ayer and eventually convey their waters into the Nashua River: Long Pond > Sandy Pond > Flannagan Pond (fed into also by Pine Meadow Pond) > Balch Pond > Grove Pond > Plow Shop Pond > Nonacoicus Brook > Nashua River.
Flannagan Pond attained its pond status as a result of human intervention in the 19th century. Left in its natural state, it would have remained a brook (draining from Sandy Pond), swamp and meadow, but this changed with the construction of a dam. The area encompassing Flannagan Pond was purchased by Calvin Fletcher in the mid-1800s, and the dam was constructed to provide power for his sawmill. In the 19th century in particular, a number of dams were constructed throughout what became the Town of Ayer (in 1871) in order to provide water power to run mills (for lumber, grist, textiles, etc.). Dams along this chain of ponds and streams led to the creation of not only Flannagan Pond, but also Balch, Grove, and Plow Shop ponds. It is also reported that during this time period, these ponds were periodically flooded (or “flowed”) during the winter months to provide a source of ice for the ice industry and were then drained in spring and summer in order to graze livestock.
Most of Flannagan Pond is now surrounded by residential development along its shoreline. This pond is also relatively densely vegetated. Unlike Sandy Pond, which is a much deeper and natural kettle pond formed by retreating glaciers, Flannagan Pond will always be shallow and therefore will always have more aquatic vegetation present. The Ayer Conservation Commission includes this pond within its annual aquatic vegetation maintenance program, along with Sandy and Pine Meadow ponds. For Flannagan Pond, this program focuses on the eradication of non-native aquatic plants (especially fanwort, but also variable leaf milfoil and curly-leaf pondweed) as well as the control of the excessively dense overgrowth of native species like water lilies, especially at the eastern end of the pond near the inlet from Sandy Pond.
Of historical interest, at one time, a local icehouse company (in addition to the Boston Ice House and the Ayer Ice Company that used neighboring Sandy Pond) operated on ‘Fletcher’s Pond’. This icehouse, however, was destroyed in a fire in 1885. It is reported that some years later, a clubhouse was built at the site of the previous icehouse, offering dinner, dancing, and a steam launch. The steam launch, departing from the dock behind John Flanagan’s house, would cruise up Fletcher’s Pond, cross under a then hand-cranked drawbridge at Snake Hill Road, then cruise around Sandy Pond before returning to the clubhouse. Over time, the reference to this pond as ‘Flannagan Pond’ became the dominant usage, replicated on area maps and referenced as such in modern State records. Nevertheless, you will find lifelong Ayer residents who still prefer to call this pond “Fletcher’s!”
Trophic Status
Ponds, lakes and other surface waterbodies can be evaluated on scales that rate their trophic status. This status indicates the amount of ‘biological productivity’ (or total weight of living biomass at time of measurement) that a waterbody sustains. Biomass in a waterbody is usually dominated by either aquatic vegetation or algae. Waterbodies can range from oligotrophic – less biomass/’good’ water quality; mesotrophic – moderate biomass/’fair’ water quality; and eutrophic to hypereutrophic – high/dense biomass/’poor’ water quality. Too many ‘nutrients’ in a waterbody (especially from phosphorus and nitrogen runoff from stormwater, nearby fertilizer use, septic systems, etc.) will lead to an increase in plant and/or algae growth and a decrease in water quality as the process of eutrophication continues. While eutrophication is a natural process of nutrient enrichment in aquatic ecosystems that takes place gradually over time, it can be dramatically accelerated by the impact of human activities that increase the flow of nutrients into waterbodies and their surrounding watershed.
According to the Geosyntec Consultants study of Ayer Ponds completed in 2016, as measured by the Carlson Trophic State Index (TSI) model, Flannagan Pond rates as eutrophic. The Carlson TSI uses water clarity and measurements of Total Phosphorus (TP) and Chlorophyll-a to make its assessment. A different model for evaluating eutrophication is the Vollenweider model which uses measurements of a pond’s ‘flushing rate’, the TP load entering the pond from external sources, and the internal TP concentration already there [i.e. from sediment and plant decomposition]). Like the Carlson TSI, the Vollenweider model also assesses Flannagan Pond as eutrophic. For a variety of reasons, this is why efforts are made to control aquatic vegetation and to reduce external sources of runoff into ponds like Flannagan Pond, in order to maintain a water quality that allows for fishing and boating.
Impairment
The Federal Clean Water Act (effective in 1972) governs water pollution in the United States, and requires states to identify waterbodies that do not meet EPA standards and are designated as “impaired.” Flannagan Pond is listed as a Category 4c impaired waterbody whose impairment is not caused by a pollutant. In the most recent report, Flannagan Pond is listed as impaired due to the presence of non-native aquatic vegetation (primarily fanwort and variable leaf milfoil), a level of impairment that does not require a specific pollution control plan. (By contrast, Grove Pond, Plow Shop Pond, and Nonacoicus Brook are all listed as Category 5 level impaired waterbodies due to the presence of pollutants.)
This sign project was funded by a community grant from the Nashua, Squannacook, and Nissitissit River Wild & Scenic Stewardship Council.