Riparian Area Integrity
Distribution of C1 and C2 streams in the Raritan River watershed
Riparian areas are transitional areas that lie between terrestrial and aquatic ecosystems (NRCS, 2007). As a result, riparian areas contain both the characteristic of upland as well as aquatic ecosystems. These areas are vital for healthy watersheds as they: protect streambanks and remove sediments and nutrients from runoff; reduce flooding and protect aquatic ecosystems; and provide habitat as well as food to terrestrial and aquatic organisms. Most researchers use the condition of riparian areas as an index to measure stream health.
Even though riparian areas provide a myriad of benefits to our society, these areas have been converted into agricultural land as well as urban land. Agricultural land can generate nonpoint source pollution that degrades water quality; urban land can increase impervious surfaces causing more runoff that can erode stream health. In our investigation of riparian areas, we assumed forest and wetlands to be natural land cover, suitable for habitat and characteristic of supporting good water quality while agricultural land, urban land, and barren land would have negative impacts on stream health. Apart from the above land use parameters, we also investigated the pattern of impervious surface inside riparian areas.
Approximately 2/3rds of all riparian buffers in the Raritan were in natural cover. Class 1 stream buffers showed an increase in altered land uses in the Upper Raritan and a decrease in altered cover for the Millstone and Lower Raritan. Conversely, Class 2 stream buffers showed a decrease across most of the Raritan basin. Overall, trends were mixed and impacts to water quality are inconclusive.
Read more about Riparian Area Integrity starting on page 47 of the State of the Raritan Report, Vol. 1