The Management Modes of Seasonal Floods and Their Impact on the Relationship Between Climate and Streamflow Downstream From Dams in Quebec (Canada)

Abstract

The goal of the study was to compare the modes of management of seasonal floods for different dams and to constrain their impact on the relationship between climate variables and streamflow downstream from the dams. At the Rawdon dam, downstream from which the Ouareau River is characterized by a natural‐type regulated flow regime, a ‘type A’ flood management mode prevails, in which the same rainfall and/or snowmelt events account for seasonal floods both in the unregulated (natural) stretch of river upstream from the dam and in the river downstream from the dam. As a result, seasonal floods in the natural setting and downstream from the dam are nearly synchronous. In contrast, downstream from the Matawin dam (Matawin River), which produces an inversion‐type regulated flow regime, the prevalent flood management modes are of types B and D, whereby seasonal floods observed upstream and downstream from the dam are not caused by the same rainfall and/or snowmelt events and, as a result, are not synchronous. This difference in seasonal flood management modes affects the interannual variability of the magnitude of seasonal daily maximum flows related to the seasonal floods. Thus, the interannual variability of these flows downstream from the Matawin dam differs significantly from that of flows upstream. No correlation is observed between climate variables and streamflow downstream from the Matawin dam. This absence of correlation disappears gradually at the annual scale, at which streamflow is correlated with rainfall, as is observed upstream from the dam. Copyright © 2013 John Wiley & Sons, Ltd.

Comparison of the Spatio-Temporal Variability of Annual Minimum Daily Extreme Flow Characteristics as a Function of Land Use and Dam Management Mode in Quebec, Canada

“…For its part, the Matawin River is entirely comprised within the Canadian Shield, where it flows into the Saint-Maurice River. All three rivers show similar physiographic features due to the fact that they all flow through the Canadian Shield [17]. Differences in their physiographic features (elevation, slope, course length, drainage density, etc.)…”

“…The Rawdon dam management mode is of regulated natural-type flow, meaning that downstream from the dam, maximum flows occur in the spring, during snowmelt, and minimum flows occur in winter (Figure 2b), as in natural rivers (Figure 2a). Therefore, the dam does not change the natural annual hydrological cycle of flow [16,17]. Its impact on the hydrologic regime is restricted to a significant increase in flood flows [17].…”

“…Therefore, the dam does not change the natural annual hydrological cycle of flow [16,17]. Its impact on the hydrologic regime is restricted to a significant increase in flood flows [17]. The dam is roughly 15-m high and the total area of its reservoir is on the order of 190 ha, for a total volume of roughly 6,000,000 m 3 [17,18].…”

“…Its impact on the hydrologic regime is restricted to a significant increase in flood flows [17]. The dam is roughly 15-m high and the total area of its reservoir is on the order of 190 ha, for a total volume of roughly 6,000,000 m 3 [17,18]. The second watershed studied is the Matawin River watershed, which is typical of forested watersheds in the Canadian Shield of Quebec.…”

The case of extreme hydrologic drought downstream from reservoirs in Quebec (Canada): The intermittent flow

“…To address this, the following two goals were defined for the present study: To quantify the extent of this extreme altered hydrological streamflow or this intermittent flow phenomenon observed downstream from reservoirs in Quebec. To analyse the link between climate and the extent of intermittent flow, the underlying hypothesis being that downstream from reservoirs that produce an inversion of the natural annual cycle of streamflow, the extent of intermittent flow is independent of climate variability. This hypothesis is based on the fact that in a recent study, Landry, Assani, Biron, and Quessy () showed that, contrary to other types of reservoirs, there is no significant correlation between streamflow and climate variables (rainfall and temperature) downstream from such inversion‐type reservoirs. …”