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1] Previous studies of river hydrometric records and Indigenous Knowledge holders claim that floodinduced recharge of ecologically important perched basins decreased across the Peace-Athabasca Delta after 1968 due mainly to hydroelectric regulation of Peace River flow. Natural deltaic processes and climate are acknowledged as additional, lesser contributors, but are challenging to evaluate. We use sediment records spanning ∼115 years from nine perched basins across the Athabasca Delta to test if unidirectional drying coincides with river regulation. Results show bi-directional hydrological changes since the early 1980s, not 1968, to reduced flooding in areas east of the Embarras River confluence with Cree/Mamawi creeks and increased flooding northward along the Cree/Mamawi distributary. The timing and pattern pinpoint the 1982 Embarras Breakthrough, a natural avulsion that diverted flow northward and away from the Athabasca Delta terminus, as the principal cause. The results demonstrate the need to factor natural deltaic processes into impending decisions on the delta's UNESCO World Heritage status and implementation of a federal Action Plan to mitigate widespread drying.

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Quantitative techniques, statistical methods and mathematical rules make the geospatial analysis more systematic, accurate and precise. In order to measure the intensity of the ongoing processes on the earth surface, evaluate the spatio-temporal changes in geographical attributes, highlight the principal factors for any geographic events and to identify the future possibilities, quantitative techniques are for most dependable. In the present article sequential changes of the shoreline, spatio-temporal extent of erosion and depositional processes of Sundarban region, West Bengal, India, have been measured following the selected quantitative techniques. The Sundarban is one of the most dynamic geomorphic units in the earth surface, situated in the northern apex of Bay of Bengal. The region has formed, sculptured and modified due to continuous sedimentation of the Ganga and the Brahmaputra systems, intense tidal hydro dynamic behavior, climatic disturbances and anthropogenic activities. In the last two century most of the parts of the active Sundarban delta has being reclaimed and occupied with dense rural settlements, most of the peoples are engaged in agriculture based rural economy, hence substantial erosion and successive regressive changes in the area have an unconstructive impact on the dwelling communities. In order to examine the net shoreline changes, average rate of end point changes and extent of erosion and depositional processes