Ten tributary locations within the Pennichuck Watershed have been continuously monitored for flow and total phosphorus, along with other common contaminants, since 2007. Flow monitoring is performed to obtain an overall understanding of how streams, rivers, and ponds respond to precipitation throughout the watershed. Total phosphorus monitoring is performed because it is a key pollutant that can lead to excess algal growth. Total phosphorus monitoring is also performed at five in-pond locations to evaluate the water supply`s response to the phosphorus loads from the watershed. Groundwater monitoring for total phosphorus at nine of the ten tributary sampling locations or nearby began in 2013 to help determine phosphorus loads coming from groundwater baseflow versus from stormwater runoff. These monitoring sites can also be viewed on the Interactive Watershed Map.