National Aquatic Resource Surveys

Coastal Plains Ecoregion - NLA 2012 Results

A total of 24,928 lakes in the Coastal Plains ecoregion are represented in the NLA. Of these lakes, 26% are natural and 74% are man-made.

Key Results

Trophic State and Key Stressors: The NLA uses trophic state as an important indicator of lake condition and assesses the extent of key stressors in the nation’s lakes.

  • In the Coastal Plains, 28% of lakes are rated as most disturbed based on trophic state, 49% are eutrophic, 21% are mesotrophic, and 1% are oligotrophic.
  • The most widespread stressors assessed are phosphorus (50% of lakes), lake habitat complexity (37%), and nitrogen and riparian vegetation cover (both 33%).

Human Use Condition: Cyanobacteria is one of three algal toxin related indicators assessed in the NLA (see also chlorophyll a and microcystins). It serves as a proxy for the presence of algal toxins.Photo of a lake in the Coastal Plains ecoregion that was sampled during the National Lakes Assessment 2012Lake sampling in Texas for the NLA 2012. Photo: Texas crew.  

  • Based on cyanobacteria cell counts, 23% of lakes in the Coastal Plains are in the most disturbed condition (i.e., pose a high risk of exposure to algal toxins).

Change from 2007 (for lakes >4 hectares)*:

  • For the Coastal Plains, no indicators showed a significant change in most disturbed condition between 2007 and 2012

To access more indicator graphics please visit the interactive NLA Dashboard.

* The change analysis is based on information from two points in time – 2007 and 2012.  The change in condition analysis only considers lakes 4 hectares and larger because smaller lakes were not sampled in 2007.