What types of natural lakes were sampled? What types of reservoirs were sampled?
The NLA sampled all types of natural and man-made lakes as long as they met the definition of lakes developed for this study (see above). This included lakes formed by glacial, volcanic or tectonic action and oxbow lakes formed from meandering river channels. It also included large and small man-made reservoirs created for energy production, drinking water supply and other purposes.
