Rock House Reservation - Carter Pond

Carter Pond

Carter Pond is a relatively shallow pond, with an area of about 2.5 acres and a watershed of about 8 acres. The pond has a healthy riparian zone (characterized by woody trees and shrubs) and healthy shoreline vegetation (characterized by sedges, grasses, rushes). Both of these areas provide important habitat for dragonflies, damselflies, mammals and amphibians.

The pond has an average depth of 1 meter and soft substrate that is characterized by inorganic sediment and undecomposed organic matter. Sunlight reaches the bottom of the substrate 40% of the time. The pond has a healthy pH and alkalinity, low levels of nitrates, phosphates and dissolved oxygen and high levels of suspended solids. Biologically, there is a high diversity of macroinvertebrate and fish populations but a low diversity and of submerged and floating aquatic plants.

It is unusual that Carter Pond has a low diversity of submerged aquatic plants, because shallow ponds usually have plants growing from shore to shore. In the case of Carter Pond, plant growth and reproduction might be limited by low levels of nitrogen and phosphorus. These nutrient deficiencies may be caused by the pond’s small pond-to-watershed ratio and/or lack of nutrient inflow from an upstream source. In addition, it is possible that the spring that feeds Carter Pond is nutrient-poor, although additional water quality testing will be needed to confirm or disprove this theory.

Carter Pond’s low abundance of aquatic plants may be contributing to another problem the pond is experiencing: low dissolved oxygen. This is because dissolved oxygen often enters the water as a byproduct of aquatic-plant photosynthesis. Thus, low numbers of aquatic plants can limit the amount of dissolved oxygen that enters the water. Lack of aeration due to stagnant water and/or warm water temperatures could also contribute to the low levels of dissolved oxygen in Carter Pond.

Carter Pond is also experiencing high levels of inorganic sediment in the water column. A visual observation of sediment deposition on the north bank suggests that sediment might be eroding into the pond from the north shore after heavy rains. This deposition could be a problem because it limits transparency, decreases benthic habitat diversity, and builds up on the bottom of the pond.

Carter Pond is also dealing with a build-up of organic matter, such as leaves and sticks, on the bottom of the pond. It is currently unclear why this accumulation is greater than decay, but it could be a result of low pond turnover rates, low numbers of decomposer in the benthic environments, or low dissolved oxygen