Northeast Lake and Pond Classification (Report)

Citation: Olivero-Sheldon, A. and M.G. Anderson. 2016. Northeast Lake and Pond Classification. The Nature Conservancy, Eastern Conservation Science, Eastern Regional Office. Boston, MA.

Abstract

We developed a mapped classification of lakes and ponds based on facors that structure lacustrine ecosystems and that could be mapped consistently across Northeastern US. The classification was based upon four key variables: water temperature, alkalinity, trophic state, and depth. Water temperature was mapped into three classes (very cold, cold, and cool-warm) to reflect the requirements and limits of aquatic organisms. Alkalinity was grouped into three classes (high, medium, low) to reflect how well the lake system was buffered from acidification. Trophic states, representing the productivity of a lake, were mapped into two classes (oligotrophic-mesotrophic and eutrophic-hypereutrophic). Depth was divided into two classes (lake, pond) using maximum depth and trophic status to estimate whether light penetrates to the bottom of the waterbody. A steering committee of state and regional experts contributed sampled data with measured values of these and other variables for waterbodies in their states. To create the mapped classification, we compiled the location of every waterbody in the region (n = 36,675), and for each waterbody we generated over 300 descriptive attributes including: morphology, dams, climate, soils, geology, conservation lands, landforms, and land cover in the watershed. We to develop a predictive model for each variable class based on the sampled data points, and we then extrapolated the model to the unsampled waterbodies used Random Forest software to estimate their class based on their descriptive attributes. All waterbodies were assigned to one of 18 classification types based on the combination of three variables: temperature class, trophic state class, alkalinity class. These types can be further subdivided into lake or pond categories to yield mapped occurrences of 36 waterbody types, for example: cold, oligotrophic-mesotrophic, low alkalinity, lake.