The vital sign selection process of the NPS Inventory and Monitoring Program (I&M) identified fish, macroinvertebrates, and physical habitat characteristics as a critical need for the parks of the National Capital Region Network (NCRN). In 2005, the National Capital Region Inventory and Monitoring Network (NCRN) initiated a long-term water quality and quantity monitoring program, funded in part by the National Park Service Water Resources Division. The Biological monitoring portion of the program is carried out every 6 years at 37 sites within 10 of the NCRN parks. The data collected using this protocol will provide much needed baseline information on the stream biological resources in the NCRN, particularly in terms of community structure and composition. The information will also be used to determine long term trends in community composition, as well as trends in the abundance and distribution of individual species.