During the period of 1960–1980, oil and gas exploration and development in Louisiana increased dramatically. Numerous large access canals and pipeline canals were dredged through deep swamp areas, across bayous, and across the Atchafalaya River. In some areas of the Basin, there are or more of access canals to every of natural bayou. These large channels ( wide by deep) have fundamentally changed the hydrology of the swamps. Deep swamp areas that were hydraulically isolated from sediment were connected directly to the river and its sediment and suffered rapid filling. The USGS has measured sediment deposition rates of up to per year where these channels enter open water, and per year on adjacent floodplains. In some places natural bayous have filled in due to flow capture by access canals.