Highway Construction in Coastal Areas. Part III. Effects of a Culvert on the Hydrography and Biology of a North Carolina Salt Marsh

摘要

A three year study of the effects of a culvert on the biota and tidal regime of a high, regularly flooded salt marsh showed the major hydrologic impact was to retard both the ebb (up to 7h) and flood (up to 3h) cycles and to decrease the maximum depth of water (up to 30 cm) in the marsh. The normal salinity cycle may be changed if there is significant freshwater input. Snails (Littorina irrorata) were restricted to the inundated surface, hence areally restricted by the culvert. Maximum abundance in the impacted (study) marsh (170/sq m) was about half of that in the adjacent control marsh (300/sq m).