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

Abstract

This study presents a comparison of the spatio-temporal variability of characteristics (magnitude, duration and timing) of annual minimum daily extreme flows (AMEF) as a function of land use and the mode of management of dams. Streamflow measured at stations not affected by dams at Joliette, along the L'Assomption River (agricultural watershed, 1340 km 2 ), and at Saint-Michel-des-Saints, on the Matawin River (forested watershed, 1390 km 2 ) on one hand, and downstream from the Rawdon dam (regulated natural-type management mode), on the Ouareau River (1260 km 2 ), which is the main tributary of the L'Assomption River, and from the Matawin dam (inverted-type management mode), on the Matawin River (4070 km 2 ), on the other hand, were compared over the period from 1930 to 2010. As far as the spatial variability of natural rivers is concerned, the magnitude and duration of AMEF are higher in the forested watershed than in the agricultural watershed. In regulated rivers, AMEF magnitude is higher downstream from the dam characterized by a natural-type management mode than downstream from the dam characterized by inversion-type management. However, downstream from the latter, AMEF occur much more OPEN ACCESSWater 2015, 7 1233 frequently and very early in the year. As for temporal variability, the Lombard method did not reveal any influence of land use differences on the stationarity of series of AMEF characteristics. In contrast, differences in dam management mode result in occurrences of AMEF downstream from the inversion-type dam progressively earlier in the year. The duration and timing of AMEF are not correlated with the same climate variables, be it in natural rivers or downstream from dams.

Effects of Land Use on Flow Rate Change Indices

“…In other words, variations in streamflow increase significantly over time in both watersheds. In the agricultural watershed, this increase may be related to increasing rainfall [18,22], while in the forested watershed, only summer rainfall has increased significantly. In addition, minimum temperatures have also increased significantly in the four seasons [18].…”

“…Two watersheds met these three criteria, namely the adjacent L'Assomption River and Matawin River watersheds. These watersheds have already been described in detail in some of our previous work [18,22]. The Matawin River watershed is fully contained within the Canadian Shield.…”

“…As a result, the watershed climate and physiographic factors that affect the spatial and temporal variability of this component of the flow regime remain unknown, as do human factors. In Quebec, although several studies have analyzed the hydrologic impacts of deforestation and agriculture on various components of flow [18][19][20][21][22], none has looked at the impacts of these two human activities on flow rate change. The goal of the present study is to fill this gap.…”

The Usefulness of the Lombard Method for Analyzing the Hydrological Impacts of Dams: The Case of the Manouane River Diversion Dam, Quebec, Canada

“…Hydrological changes induced by the diversion dam built on the Manouane River are different from this general scheme, because that dam did not affect maximum daily flows, but produced a significant decrease in minimum daily flows. Previous work looking at the hydrological impacts of dams in Quebec distinguished three types of impacts, each corresponding to a specific dam management mode [1,[29][30][31][32][33][34]. The first type of hydrological impact is characterized by a decrease in annual and seasonal maximum and minimum daily flows.…”

Analysis of the Influence of the 2007–2008 La Niña Events, Land Use, and Dam Management Modes on the 2008 Spring Freshet Characteristics in Quebec, Canada

“…As far as human factors are concerned, many dams have been built in Quebec since the nineteenth century to develop natural resources and fulfill the demand for both domestic and industrial hydroelectric power [4]. Many studies have looked at the impacts of these works on streamflow [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and have shown that the extent of changes in streamflow downstream from these dams depends, among other things, on the dam management mode. Four management modes have been identified and described, each corresponding with a specific regulated hydrological regime downstream from dams.…”