The channel approaching a H flume should be at least 3-5 times the maximum anticipated head at the point of measurement of the flume (Hmax).
Approach sections can be provided with Openchannelflow H flumes. They can be integral with the flume - forming one continuous piece - or they can be fabricated separately and bolted to the flume prior to shipment.
Alternatively, approach sections can be formed onsite out of available materials (plywood is common in field run-off applications - concrete is common at treatment plants).
