| Abstrakt: |
Irrigation and drainage engineering encompasses the human-made supply of water as well as the artificial drainage of excess water. A basic feature of many historical and modern irrigation and drainage systems has been the integrated use of hydraulic structures, most often low-head structures. These structures play a key role in water storage, conveyance, flow control and measurement, and energy dissipation. Yet, most systems are often designed assuming relatively simplistic design flow conditions. In this contribution, a number of relevant key challenges for hydraulic structures used in irrigation and drainage systems are discussed, using the operation of minimum energy loss weirs, the nonlinear behaviors of circular-crested weirs and the instabilities in fish-friendly box culverts equipped with sidewall baffles as examples. Altogether, the design approach of many hydraulic structures needs a rethink, far beyond the naive optimization for simplistic design flow conditions, with a greater focus on the safe and efficient operation across a broad range of less-than-design discharges, to be embedded in the design optimization approach. [ABSTRACT FROM AUTHOR] |
