This chapter presents a discussion of various types of river engineering structures. The aim of this chapter is to familiarize the reader with solutions to a wide spectrum of river engineering problems. This chapter covers an overview of the following types of river engineering structures: (1) flood control in Section 9.1; (2) river closure and local jet scour in Section 9.2; (3) canal headworks in Section 9.3; (4) bridge crossings in Section 9.4; (5) navigation and waterways in Section 9.5; and (6) dredging in Section 9.6.

River flood control

This section discusses river engineering solutions to flood control. The methods include flow regulation with reservoirs in Subsection 9.1.1, floodways in Subsection 9.1.2, channel conveyance in Subsection 9.1.3, and levees in Subsection 9.1.4.

Reservoirs

The most direct method of flood control is the storage of surface runoff. Flood control with reservoirs redistributes floodwaters and attenuates floodwaves. A reservoir fills up when the inflow exceeds the outflow, and water storage acts as a buffer to decrease the peak discharges and increase the low discharges. An increase in low discharges is beneficial to hydropower, navigation, and irrigation. It is best to keep the reservoir as full as possible in order to maintain sufficient storage capacity to increase the low discharge reserve in periods of drought. For flood control, however, the reservoir should be kept as low as possible to store unexpected large floods and decrease flood peaks.