Tidal Inlet Response to Jetty Construction.

• Main Author: Kieslich,James M
• Other Authors: ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
• Format: Text
• Language: English
• Published: 1981
• Subjects: Physical and Dynamic Oceanography; Civil Engineering; *Inlets(Waterways); *Sediment transport; North Atlantic Ocean; Mexico Gulf; North Pacific Ocean; Coastal regions; Underwater structures; Ocean currents; Sediments; Accumulation; Channels(Waterways); Migration; Cross sections; Modification; *Jetties; LPN-CERC-B31647; Pacific; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/ADA112448; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA112448

Thirteen tidal inlets located on the Atlantic, gulf, and Pacific coasts of the continental United States were selected for a study of the response of inlet ocean entrances to manmade improvements. Inlet entrance behavior following jetty construction were evaluated and guidelines for the functional design of inlet entrance improvements are suggested. The inlets considered in the study were those where a single updrift or downdrift jetty was built first. The construction of single jetties at inlet entrances has resulted in migration of the channel thalweg toward the jetty regardless of the inlet-bay orientation, the jetty angle with the shoreline, the position of the jetty relative to the direction of net longshore sediment transport, the ratio of net-to-gross transport, or the gross transport. In some cases, this has caused undermining of the jetty. For the inlets studied, the annual channel thalweg migration averaged 31 percent of the total distance available for migration following construction of a single updrift jetty, and 49 percent of the total distance available for migration following construction of a single downdrift jetty. The channel cross-sectional area usually decreased following construction of a single updrift jetty; the decrease in area ranging up to 40 percent. Sufficient data were not available to quantify channel area response following construction of a single downdrift jetty.