Long-term monitoring of the Rhode Island shoreline: Understanding beach cycles, headland and barrier change, and the effects of accelerated sea-level rise
- Univ. of Rhode Island, Kingston, RI (United States). Dept. of Geology
- Applied Science Associates, Inc., Narragansett, RI (United States)
- Baker Environmental, Princeton, NJ (United States)
- The Earth Time Project, Ketchum, ID (United States)
The 33 km long microtidal shoreline of southern Rhode Island is a natural shoreline laboratory that is being used to track the effects of storm-fairweather cycles and extreme storm events, and to model the effects of accelerated sea-level rise due to global warming on barriers and headlands. Thirty years of beach profile monitoring (10 stations) indicates seasonality at some stations, mixed on-off seasonality at some stations, mixed on-off seasonality at others, and five and ten year patterns of variation at most locations. The last ten year cycle reached peak accretion in 1988 with berm widening, eolian dune deposition, and the development of a temporary storage feature termed the backshore reservoir. Most beaches and associated barrier or headland cores have had a net loss of sediment since 1988, with erosion and removal of backshore reservoir material. Mapping from vertical aerial photos indicates that erosional retreat of barriers ranges from 0.4--1.0 m[center dot]yr[sup [minus]1] (1939--85), and headlands from 0.2--0.9 m[center dot]yr[sup [minus]1], accomplished during sou'easter storm cycles and major hurricanes. Field mapping of barrier and headland changes after storm events (5--20 year storms) indicates that frontal erosion combined with washover sand accumulation have been underestimated as agents of change, particularly on headlands. The authors have modified the standard FEMA/NAS storm erosion configuration to better forward-model the effects on the shoreline resulting from projected sea-level rise due to global warming. They presently use an isostatic subsidence of 15 cm [center dot] 100 yr[sup [minus]1] based on Newport, RI gauge records, and accelerated eustatic sea-level rise based on IPCC (1990) predictions that give 1.0--1.45 m rise by 2,100.
- OSTI ID:
- 5934154
- 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
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