Estuarine circulation and sediment transport trends in the lower Saco River
- Boston Univ., Boston, MA (United States). Dept. of Geology
- Univ. of Maine, Orono, ME (United States). Dept. of Geological Sciences
Saco River estuary is located along the southern Maine coast at the southern end of a sandy barrier system within the Saco Embayment. The tidally-influenced portion of the river extends 10 km upstream where it is punctuated by two dams at Factory Island. The mouth of the river is shallow (< 3.0 m deep) and stabilized by two jetties 1.0 km in length. Hydrographic data indicate that the estuary is vertically stratified with middle estuarine locations exhibiting strong salinity gradients from 2 to 12 ppt at the surface to 20 to 29 ppt at the bottom. Within 3 km of the dam, salinities are low throughout the tidal cycle (0 to 4 ppt) which contrasts with the river mouth where salinities range from 10 to 32 ppt and stratification is best developed during early ebb. Water temperatures correlate well with the salinity variations both spatially and temporally. The upper two thirds of the estuary are dominated by seaward flow with stronger average and bottom ebb current velocities. In the lower section of the estuary, average current velocities continue to be ebb dominant, however, the bottom flow exhibits stronger flood currents (by 4 to 16 cm/s). This condition reflects the influence of the saltwater wedge. More than 100 bottom samples collected from the dam to 1 km offshore of the jetties reveal that the estuary is floored by medium to coarse sand with finer-grained sediment occurring in wide tidal flat portions of the river. The coarsest sediment is found in gorges and just downstream of the dams. Seaward of the jetties the sand is fine. These findings indicate that sediment, which accumulates and is dredged at the estuary mouth, has a riverine source. The polishing of turbine blades at the dam, which occurs during periods of high discharge, appears to corroborate this. Most transport to the river mouth occurs during spring freshets and flood events.
- OSTI ID:
- 5878915
- Report Number(s):
- CONF-9303211-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:2; Conference: 28. annual Geological Society of America (GSA) Northeastern Section meeting, Burlington, VT (United States), 22-24 Mar 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
Similar Records
Storm-induced sand transport and bedform genesis at beach and shoreface environments of the Maine Coast
Late Quaternary history of southern Chesapeake Bay
Related Subjects
ESTUARIES
SALINITY GRADIENTS
SEDIMENTS
MAINE
DEPOSITION
ATLANTIC OCEAN
ENVIRONMENTAL TRANSPORT
GEOLOGIC DEPOSITS
SALINITY
SEASONAL VARIATIONS
SEAWATER
STRATIFICATION
WATER CHEMISTRY
WATER CURRENTS
CHEMISTRY
CURRENTS
DEVELOPED COUNTRIES
HYDROGEN COMPOUNDS
MASS TRANSFER
NORTH AMERICA
OXYGEN COMPOUNDS
SEAS
SURFACE WATERS
USA
VARIATIONS
WATER
580000* - Geosciences