An area of broken, fast flowing water in a stream, where the slope of the bed increases (but without a prominent break of slope which might result in a cascade or waterfall), or where a gently dipping bar of harder rock outcrops
Data Dictionary for rapid_cl: https://docs.topo.linz.govt.nz/data-dictionary/tdd-class-rapid_cl.html
This layer is a component of the Topo50 map series. The Topo50 map series provides topographic mapping for the New Zealand mainland, Chatham and New Zealand's offshore islands, at 1:50,000 scale.
Further information on Topo50:
http://www.linz.govt.nz/topography/topo-maps/topo50
