New seawalls are not permitted if they will adversely affect beaches and dunes. As sea level continues to rise in Maine, there may be places where waves regularly wash up the rocky shore and cause erosion of upland soil. Currently, no clear statutory or rule language exists for seawalls outside of the coastal sand dune system. Existing seawalls located along a rocky shore or on ledge may potentially be expanded in terms of their height with an appropriate permit on a case-by-case basis, if regular flooding and overtopping and subsequent erosion can be proven. The use of rip-rap on a rocky shore may be permitted by the DEP.