RESOLVING STORM INTENSITY FROM OVERWASH DEPOSITS: A CASE STUDY AT BALD HEAD COVE, MAINE

Although many storms impact the New England coast, events large enough to breach and reshape a barrier's morphology are relatively rare. New England experiences 15-20 extratropical storms (northeasters) annually, but hurricanes occur much less frequently (1 every 4 yrs). Still, hurricanes are the storms of record in New England in terms of storm surge magnitude, sediment transport, and changes in coastal morphology. In the Gulf of Maine the Great Colonial Hurricane of 1635 is the storm of record. Along the peninsular coast of Maine, this storm resulted in widespread overwash into backbarrier ponds and wetlands. Radiocarbon and optically-stimulated luminescence techniques date a 1635 overwash feature at Seal Cove. At adjacent Bald Head Cove, ground-penetrating radar surveys and 10 sediment cores indicate that the barrier lithosome is up to 4 m in thickness overlying an irregular bedrock surface. The washover has aggraded the rear of the barrier by 1-2 meter and unconformably overlies a 5 to 30 cm-thick freshwater peat. Topographic surveys coupled with wave run-up and inundation models are used to determine the minimum energy necessary to transport sand from the beach and dune system into the backbarrier pond. Constraining the storm surge height, storm duration, and wave energy provide parameters that are inputted into a SLOSH model to investigate the paleo-meteorological conditions of the Great Colonial Hurricane as it transited through the Gulf of Maine. This type of analysis can be used to reconstruct the magnitudes of past storms and extend historical records of major meteorological impacts.