This paper addresses problems associated with fishways in flow control structures at low head dams on small watersheds (i.e., between 3 and 50km(2), between 1 and 20 sq mi). Guidelines and rationale are given for design of fishways for commonly used flow control structures in this category in the Maritime Provinces on Canada's east coast. Information takes into account the size of the drainage area, anticipated flows and provisions for accommodating flood flows, the proposed head at the dam, the types of fish species to be passed and the timing of the upstream fish migration at the location of the barrier.