Recently, an FHMNA member requested updates from Raymond Jack, Public Works Director for the Town of Falmouth, on the water quality this summer in Little Pond.
Below is the text of an email which Mr. Jack sent to our member. We appreciate the time Mr. Jack took to respond and wish to share this thorough assessment with our members.
“I personally conducted a site visit today to observe current conditions at Little Pond. The inlet channel and culvert depths appear normal and flushing velocity appears normal on an outgoing tide. There is some shoaling on the pond side of the inlet, but not sufficient to impact tidal flow. Thus, there are no maintenance activities to be performed at this time that would increase either velocity or volume.
The trophic (or health) level of a pond or estuary at any given time is dependent upon a variety of factors such as:
- Water temperature – higher temperatures result in increased biological activity and a reduced capacity of the water body to maintain dissolved oxygen.
- Ambient air temperatures – the higher the ambient temperature, the higher the water body temperature.
- Nutrient load – results in algae proliferation and corresponding reduction in dissolved oxygen
- Rainfall – normal rainfall introduces fresh, oxygenated water to the water body by virtue of runoff throughout the watershed area
- It is noted that we have had very little rainfall this season
- Certain species of algae produce unpleasant odors.
- Algal blooms consume oxygen. The algae then die and settle to the bottom where they decompose resulting in greater oxygen depletion and odors.
- Organic matter – leaves and other organisms decompose in the benthic (bottom) zone and produce sulfide compounds (odorous compounds) as a result of natural decomposition
- Seasonal turnover – this phenomenon occurs when surface water temperatures approach 39 degrees F. (usually in the Spring and Fall). Water is then at its greatest density and the pond literally “turns over” and stirs up decaying matter on the bottom which causes high turbidity (suspended materials that reduce clarity) and results in obnoxious odors. The effects can be pronounced and last for days or weeks.
- Note: the same phenomena can occur during high-wind events whereby the water body is “wind-stirred”.
Healthy pond systems are generally very resilient and adapt well to variations of the above factors without exhibiting deleterious effects. Ponds that are weakened with excessive nutrient loading however are not so resilient. Such is the case with Little Pond (and others as well).
There is no quick-fix to the conditions Little Pond is experiencing. During my visit, there was a discernible odor in the area and an alga was present along cove areas. It is not possible to determine whether the odors are algae related or a result of decomposition (sulfur gases), but likely a combination of both. It appears that the condition is being exacerbated by lack of rain – drought conditions impart tremendous stress on water courses and water bodies.
I would not minimize the beneficial effects of sewering the area – this single effort will dramatically improve the overall health of the pond in a relatively quick timeframe. As previously indicated, a healthy pond system is highly adaptive to changes of natural environmental conditions.
Widening of the inlet can provide some measure of improved tidal flushing, but will not solve the problem.”