The Lower Hop Brook is a core aquatic site in Domain 01 Northeast in Massachusetts. HOPB site is a 3rd-4th order wadeable stream that flows into the Quabbin Reservoir in central Massachusetts. The section of stream selected by NEON flows from Shutesbury Road to the inlet of reservoir. Several beaver dams and ponds characterize the area upstream of Shutesbury Road. The Lower Hop Brook site is a clear-water, moderate gradient stream with gradient increasing as the stream approaches the reservoir. Minimal beaver activity (dams, ponds) is anticipated in the upper portions of the reach during the life of the NEON project. Large debris dams characterize the reach downstream. Substrate ranges from sand to cobbles, boulders, and finally bedrock outcrops downstream. The stream canopy is predominantly a mixed deciduous, northern hardwood forest with beech trees near the stream. Total data products collected at this site 78.