Flooding and channel morphology are the result of many factors. Land use is considered one of the major factors in flood genesis and, consequently, in the morphological evolution of river channels. Much work has already been devoted to the impacts of land use on river floods (e.g., Acreman and Holden, 2013; Archer, 2003; Bandyopadhyay and De, 2018; Blöschl et al., 2007; Brandolin, Avalos, & De Angelo, 2013; Bronstert, Niehoff, & Bürger, 2002; Brown et al., 2005; Bullock and Acreman, 2003; Buytaert et al., 2004; Caissie et al., 2002; Cooper et al., 2013; Fashae and Olusola, 2017; Lane et al., 2005; Li et al., 2007; Nabegu, 2014; O’Connell et al., 2007; Ott and Uhlenbrook, 2004; Petersen et al, 2017; Pfister et al., 2004; Poff et al, 2006; Robinson and Dupeyrat, 2005; van Roosmalen et al., 2009; Shepherd et al., 2010; Storck et al., 1998; Tan and Gan, 2015; Wang and Hejazi, 2011; Zhang et al., 2018). Several studies have studied the impacts of land use on the morphological evolution of channels (e.g., Clark and Wilcock, 2000; Gordon and Meetemeyer, 2006; Kasai, 2006; Lu, 2005; Towsend et al., 2004; Vanacker et al., 2005; Yan et al., 2019; Zeiger and Hubbart, 2019). However, the latest studies focus mainly on deforestation, urbanization and agriculture. No study has yet examined the impacts of wetlands on channel morphological evolution. However, much work has already been devoted to the hydrological impacts of these wetlands. In their almost exhaustive summaries, Bullock and Acreman (2003) as well as Acreman and Holden (2013) have shown that these hydrological impacts induced by wetlands can vary from one watershed to another depending on several following factors: landscape location and configuration, soil characteristics, topography, soil moisture status, etc. Morphological, these conclusions suggest that wetlands can induce different morphological impacts. It therefore becomes extremely important to determine the impacts induced by wetlands on the morphological evolution of the river channels according to the hydrological changes they induce. This problem has never been analyzed in the scientific literature to our knowledge, particularly in Southern Quebec. It is therefore imperative to fill this gap with regard to Quebec, because for two last decades, like many regions in the world, this province of Canada has been facing several catastrophic floods which have causes extensive and expensive material damages. These floods are obviously attributed to climate change. One of the solution mentioned in public opinion is the restoration of wetlands, the area of which has significantly decreased over time in Quebec due to the intensive development of agriculture and urbanization. To validate this thesis, it is therefore important to determine the impacts of these wetlands on the high and low intensities flood flows and, by incidence, on the morphological evolution of the river channels.
In Quebec, several studies have already been done on the impacts of agriculture on river flows (e.g., Assani et al., 2016; Hadeland et al., 2007; Lavigne et al., 2014; Muma et al., 2011, Muma et al., 2016; Quilbé et al., 2008; Sylvain et al., 2015). Others have examined the impacts of wetlands on the hydrology of small headwaters basins (e.g., Branfireun and Roulet, 1998; Devito et al., 1996; Fraser et al., 2001; Quinton and Roulet, 1998; Roulet, 1990a, 1990b, 1991; Roulet and Woo, 1986). However, no study yet exists that examines how these wetlands impact channel morphology in relation to flood characteristics. To fill this gap, this study will compare the annual flood characteristics and morphology (bankfull width and sinuosity) of two watersheds, which differ mainly in wetland area, in southern Quebec. The purpose of this study is to determine whether wetlands can mitigate or amplify the intensity and/or duration of high and low flood flows and their impacts on channel morphology.