MONITORING OF THE NORTH RIVER WATERSHED IN PEABODY, MASSACHUSETTS

The North River drainage basin is the largest urban watershed emptying into Salem Sound in northeastern Massachusetts. The drainage basin consists of the Goldthwait, Strongwater, and Proctor brooks that converge in the vicinity of downtown Peabody, MA to form the North River. Much of the North River system has been modified to flow through culverts and channels to suit the needs of factories, houses, and railroads. Through the years, the North River system has caused wide scale flooding during moderate rain events. The city of Peabody has started a project to modify the culverts and channels to decrease the potential for flooding. However, very little data on the current behavior of the North River system has been collected to date.

A station was selected along the North River downstream of the convergence of the three brooks and downtown Peabody. At the station, stream discharge, water chemistry, and stream slope were measured to provide data needed to compare to that collected after the modifications are complete. A Swoffer flow meter was used to collect water velocity data in order to compute the river discharge. A YSI multiparameter geochemical probe was used to collect data on water temperature, conductivity, pH and dissolved oxygen. An auto level and surveyor's rod was used to determine the stream bed and water surface slopes while bank full stage was estimated through observations of bank scouring. The measurements were taken over several months in order to capture some seasonal changes to river behavior.

Overall, discharge in the North River during the monitoring period was relatively low. However, two small rain events were captured resulting in elevated discharge. Increases in discharge of the North River are rapid consistent with the highly developed drainage area in the urban watershed. Although flooding did not occur during these rain events, the discharge in the river reached bank full stage. Stream bed slope is relatively shallow but does increase downstream. A tidal effect on discharge and water chemistry was observed just downstream of the station where the stream bed slope begins to increase. Currently, the full extent of the effect of the tides on stream discharge and flooding is not well understood. A permanent station should be established after the modifications to the drainage basin are complete.