side channel spillway
траншейный водосброс
A spillway whose crest is roughly parallel to the channel immediately downstream of the spillway.
SourceSide channel spillways are located just upstream and to the side of the dam. The water after flowing over a crest enters a side channel which is nearly parallel to the crest. This is then carried by a chute to the downstream side. Sometimes a tunnel may be used instead of a chute.