Alteration of wetlands or watercourses. In any district, no alteration of wetlands or watercourses, whether by excavation, filling, grading, clearing, draining or otherwise and whether or not incidental to activities otherwise permitted, shall be made in contours (whether submerged or above water level), water levels or flow of such wetlands or watercourses without review as to the effect of such alteration and any related facilities on water recharge areas, water table levels, water pollution, aquatic animal and plant life, temperature change, drainage, flooding, runoff and erosion. This review and approval of such alteration shall be made by the Planning Board.