Why is phosphorus so important?
Phosphorus (P) is a naturally occurring and essential nutrient for both plant and animal growth. Phosphorus is found in the soil, animal manure, most fertilizers, storm water runoff and human waste products. It is often found to be the plant growth-limiting nutrient in lakes. As long as phosphorous is unavailable or in low amounts, plant growth in aquatic systems will stay in check. Once it is freely available, plants can grow to excessive levels. This potentially severe increase in plant growth (algae and rooted plants) is usually associated with a condition known as 'eutrophication,' which eventually leads to declining water quality.
Again, what is eutrophication?
According to the Oxford Dictionaries, eutrophication is “excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.” The process of decay can deplete the water of oxygen and may give rise to algal blooms and reduction of fish species.
Spofford Lake exhibits three characteristics of eutrophication: oxygen impairment, the reduction in fish stocks and, if not an algae bloom, the appearance of cyanobacteria in 2020.
How does phosphorus contribute to eutrophication?
Phosphorus entering lakes and other waterbodies will accumulate in the sediments. When eroded soil enters the Lake, both phosphorus and the nitrogen that is released from the soil contribute to eutrophication. The Spofford Lake Watershed Management Plan estimated total phosphorous loading by source to be: 50% watershed, 25% atmospheric, 15% septic systems (likely underestimated), 6% internal loading, and 4% waterfowl.
What can be done to reduce phosphorus levels in the Lake?
We must work to manage: 1) stormwater runoff, 2) eliminate shoreline erosion and 3) curtail household run-off into the Lake. Moreover, we must eliminate the introduction of new sand to beaches as this sand may contain unwanted nutrients, like phosphorous. To the extent not already done, eliminate the use of phosphates in fertilizers and household products.
What is the SLA doing to reduce run-off into the Lake?
SLA has sought out NH DES two grants to reduce runoff rom major sites, e.g., the boat ramp, Camp Spofford, the Spofford Yacht Club and from number of private residences around the Lake.
How do these grants work?
NH DES offers grants as part of its Watershed Assistance Program. Known as Section 319 or 319 grants, the State solicits projects to address “nonpoint source pollution (NSP)” through the implementation of watershed-based plans in priority watersheds. Projects must address NPS problems and must have a measurable way to assess progress and determine success.
The watershed-based plan must have a clear water quality goal and meet a number of EPA requirements. Funded programs must make reasonable progress toward achieving the water quality goal established in the watershed plan.
How did SLA first receive its first grant?
As a prerequisite, the Spofford Lake Watershed Management Plan was completed in the 2018. With this done, the first grant was applied for and received in late 2019.
How were candidate properties chosen?
Properties were chosen by Dover NH-based FB Environmental Associates after an analysis of estimated stormwater runoff of all lake shore properties. FB Environmental then visited the nine properties in early 2020 to produce a specific plan for each location. As of this writing, two projects are complete with the remaining scheduled to be completed in 2021.
The total project is valued at $133,333 of which the grant provides $80,000 (60%) in financial support, i.e., for consultants and remediation materials. Local groups are responsible for providing the remaining 40% or $53,333 in the form of volunteer time or expenses related to 'improving the water quality of Spofford Lake'.
Is SLA applying for additional grants?
After a very positive first experience, the SWRPC and SLA have applied for a second similar grant. This project will again include helping shoreline property owners reduce runoff and will work to better direct water flow from Route 9 at and around the boat ramp. Grant approval decisions will be made later this spring.
What can I do to minimize runoff from my property?
There are a number of simple steps that homeowners can take to help. The state offers a free "Soak Up the Rain" guide with tips and strategies.
Also, reach out to the SLA to see if your property might be eligible for grant subsidies.
How else can I assist?
Page updated May 9, 2021