Water is necessary for survival. Humans have long been collecting rainwater and creating irrigation systems to redirect water and manage excess water. Societies from the Mesopotamian to Incan civilizations used irrigation systems to ensure reliable water sources. Today, hydraulic structures play a key role in managing flow control and measurement, storage, conveyance, and energy dissipation of water. Low-head hydraulic structures such as culverts, canals, sills, weirs, gates and outlets are often the structures of choice, and their design can be based upon theoretical, physical, and numerical modeling, or a combination. In a recent state-of-the-art review paper in the Journal of Irrigation and Drainage Engineering, researcher Hubert Chanson explored current practices for applications of three low-head hydraulic structures and their viability.
In “Low-Head Hydraulic Structures in Irrigation and Drainage Engineering: Challenging Operation and Design Implications,” the three applications that Chanson describes are 1) the operation of minimum energy loss weirs, 2) the nonlinear behaviors of circular-crested weirs, and 3) the instabilities in fish-friendly box culverts equipped with sidewall baffles. Understanding the role that a particular hydraulic structure plays within the entire water infrastructure network is critical to ensure reliable and sustainable water management. Chanson’s work highlights challenges in current systems and future things to consider. Learn more about the relationship low-head structures have within irrigation and drainage engineering at https://doi.org/10.1061/JIDEDH.IRENG-10288. The abstract is below.
Abstract
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.
Read more about why low-head hydraulic structure designs such as weirs and culverts needs a rethink in the ASCE Library: https://doi.org/10.1061/JIDEDH.IRENG-10288.
