USGS NAWQA: The Ecological National Synthesis (ENS) Project

Four Primary Objectives of the ENS Project:

Assess the status and trends of aquatic ecological conditions (invertebrates, fish, algae and habitat) in rivers and wadeable streams.

Relate ecological conditions to chemical stressors (such as nutrients and pesticides), physical disturbances (such as habitat and hydrologic alterations) in the context of different environmental settings and land uses.

Enhance understanding of factors that influence the biological integrity of streams and how these stream ecosystems may respond to diverse natural and human factors.

Develop key ecological indicators of aquatic health.

Consequences of land-cover misclassification in models of impervious surface

McMahon, G.

Photogrammetric Engineering & Remote Sensing, v. 73(12), p. 1343-1353

ABSTRACT.— Model estimates of impervious area as a function of landcover area may be biased and imprecise because of errors in the land-cover classification. This investigation of the effects of land-cover misclassification on impervious surface models that use National Land Cover Data (NLCD) evaluates the consequences of adjusting land-cover within a watershed to reflect uncertainty assessment information. Model validation results indicate that using error-matrix information to adjust land-cover values used in impervious surface models does not substantially improve impervious surface predictions. Validation results indicate that the resolution of the landcover data (Level I and Level II) is more important in predicting impervious surface accurately than whether the land-cover data have been adjusted using information in the error matrix. Level I NLCD, adjusted for land-cover misclassification, is preferable to the other land-cover options for use in models of impervious surface. This result is tied to the lower classification error rates for the Level I NLCD.