A variable turbidity maximum in the Kennebec estuary, Maine

A turbidity maximum has been observed in the Kennebec estuary during modera te and low flow conditions near the upstream limit of salinity intrusion. H ydrographic, ADCP, and transmissometer data were collected at different riv er flow levels and seasons during 1995-1998. The location of the tip of the salt intrusion changes dramatically and during high runoff may be flushed from the channel of the estuary along with the accumulated particles in the turbidity maximum. It is hypothesized that the estuarine turbidity maximum (ETM) was absent 18% of the time with occurrences in all seasons during 19 93-1999 based on river flow volumes from the Kennebec and Androscoggin Rive rs throughout the study period. When the flow is moderate and low, which oc curred 73% of the time on average, a region of high turbidity can be found as far as 40 km upstream of the month. Suspended particulate loads are low in the ETM, on the order of tens of mg l(-1) and may vary with the length o f time that the ETM has been present.