ABSTRACT
The fundamental concept in the approach to the design of a fishway to overcome a natural obstruction is different from that in the case of a dam. The natural obstruction to migration is in most cases a part of the natural environment of the fish it affects. The population of migrating fish has presumably become adjusted to some extent to natural environment. With a fishway at a dam, the primary aim is usually the ultimate one of providing for no delay and no physical impairment of the fish, will in all probability inevitably result in depressing the population. Hydraulic conditions at a natural obstruction are not normally subject to any degree of control as they are at a dam. Many fishway designers have expressed the view that fishways with staggered orifices or slots in the weirs or baffles are not entirely satisfactory. Having selected the functional dimensions and the location of the fishway, the structural design can proceed.
