This report describes flow-control methods for reducing ice problems in rivers. Objectives include reducing ice interference with winter hydroelectric production and navigation, ice jam flood mitigation, as well as ensuring minimum winter flows for fish and water supply. The winter season is divided into three periods. During early winter, the main objective of flow control is to promote the rapid formation of a smooth, stable ice cover. For the midwinter period, the aim of the river regulation is to maintain an intact ice cover and avoid premature ice breakup. During the final winter period, the goal is to minimize adverse effects of ice breakup. Examples illustrate the methods and objectives, emphasizing innovative approaches. Available flow regulation planning tools are described and valuable research directions identified.

This report describes flow-control methods for reducing ice problems in rivers. Objectives include reducing ice interference with winter hydroelectric production and navigation, ice jam flood mitigation, as well as ensuring minimum winter flows for fish and water supply. The winter season is divided into three periods. During early winter, the main objective of flow control is to promote the rapid formation of a smooth, stable ice cover. For the midwinter period, the aim of the river regulation is to maintain an intact ice cover and avoid premature ice breakup. During the final winter period, the goal is to minimize adverse effects of ice breakup. Examples illustrate the methods and objectives, emphasizing innovative approaches. Available flow regulation planning tools are described and valuable research directions identified.

"Specifically, this study has examined the impacts of winter ice formation on flow regulation and water supply requirements from Gavins Point Dam to the confluence of the Missouri and the Mississippi Rivers."--P. [1]

Describes the effects of flow regulation on the freeze-up processes of part of the Peace River downstream of the Bennett Dam, which has regulated the river flow since 1972. Ice modelling and a review of ice observations and other field data were used to characterise the extent of flow regulation and its effects on ice in the river channel. Explicit equations and algorithms are presented that quantify the processes by which an ice cover forms on large regulated and non-regulated rivers. Work previously undertaken on the Peace River is also described to provide a framework for the calibration of these algorithms for the river in both its regulated and non-regulated condition. A procedure was developed for forecasting freeze-up on a non-regulated river and a stability relationship was derived that uses both air temperature and discharge to determine whether a juxtaposed or consolidated ice cover will form. In addition, the hydraulic characteristics of the Peace River were evaluated for six reaches using the existing data base.