Lyman Pond, Middlefield
Lyman Pond is a 0.6-acre water body bordered to the south by Lyman Golf Course and to the north by the access road to Lyman Orchards Farm Store at the Apple Barrel. The pond provides sediment retention to protect the larger downstream farm store pond which provides a tranquil setting for the customers. Our July 8, 2020 survey found the pond’s shoreline to be completely vegetated with shrubs, small trees, a patch of cattails, and arrowhead. Lyman Pond is very shallow with a maximum depth of less than one meter. The substrate is mainly organic muck likely derived from a combination of upstream sediment, decayed leaves, and aquatic plant remnants. A sparse coverage of duckweed and watermeal was present on the surface. Patches of native coontail and western waterweed were randomly distributed through the pond as well as invasive curlyleaf pondweed. Often these plants reached the surface. The shallowness of the pond may be limiting its effectiveness in catching upstream sediment and preventing it from moving in the Farm store pond.
Our water tests found an extremely very high pH and alkalinity of 9.7 and 173 mg/L respectively. A high pH often occurs when algae and plants are conducting photosynthesis and creating oxygen by removing carbon dioxide. This is confirmed by the observed extremely high dissolved oxygen concentration of 14.5 mg/L. The water temperature was very warm (29.3 °C) which also speeds photosynthesis. Total phosphorus is a key indicator of the eutrophic (fertility) state of a water body. Oligotrophic (low fertility) ponds (<10 ppb) are typically clear free nuisance algae. Lyman Pond had a total phosphorus concentration of 50 ppb which classifies the pond as hypereutrophic and very prone to algal problems. The ponds duckweed and watermeal population could utilize the phosphorus and cover the pond which would limit algae and rooted plants.
|Species recorded in our 2020 survey of Lyman Pond.
|Arrowhead||Curly leaf pondweed*|
|Common duckweed||Western waterweed|