Are streams sampled by the NAWQA study representative of all streams in the conterminous United States?
No. Aggregation of NAWQA findings for streams across all land-use categories would not accurately represent all streams in the conterminous United States. The NAWQA study placed greater emphasis on sampling streams that drain agricultural and urban watersheds relative to those in undeveloped watersheds. Streams sampled by NAWQA include a higher proportion of agricultural (27 percent) and urban (11 percent) streams and lower proportions of undeveloped (32 percent) streams compared to the proportion of agricultural (16 percent), urban (1 percent) and undeveloped (61 percent) streams represented by all streams in the conterminous United States.
