The Hydrological Functions of a Boreal Wetland

Abstract

Wetlands are important to boreal catchment hydrology and water chemistry regimes because they are often situated at the outlet of headwater basins. There is understanding of runoff and geochemical processes that predominate in these wetlands. However, an investigation to improve understanding of the dynamic of hydrological function is absent. This paper addresses the nature of the collection, storage, transmitting and contributing functions of one typical wetland in Canada's Precambrian Shield. The majority of water enters from the larger upstream watershed. Excess water from this source is stored near the bisecting stream, where it interacts little with water collected from other sources. Outflow from the wetland is dominated by surface runoff. There were two hydrological functional phases during the study. During the first phase, the wetland merely transmitted streamflow from higher parts of the watershed. There was a diversity of hydrological function during the second portion of the study. Outflow chemistry during this second phase indicates that even when the wetland was contributing, outflow was composed of water that had very little residence time in the wetland. These results have implications for how hydrological models represent heterogeneous catchment conditions or how they may be coupled to biogeochemical models.

Hydrological Function of a Mountain Fen at Low Elevation Under Dry Conditions

“…Canopy resistance was calculated using the Jarvis approach (Spence et al, ; Verseghy, McFarlane, & Lazare, ): …”

“…Fen hydrological function was assessed using the Spence () method, with modification, at a daily time step. This method has been employed elsewhere to assess when wetlands are predominantly storing, transmitting, and contributing (Goodbrand et al, ; Spence et al, ). The storage function predominated when the fen outflow rate was lower than the absolute value of daily ΔS.…”

Evaluation of a wetland classification system devised for management in a region with a high cover of peatlands: an example from the Cook Inlet Basin, Alaska

“…Morrice et al (2008) found that a similar classification system using flow path as a hydrologic factor did not define hydrologically distinct groups of Great Lakes coastal wetlands. These classification systems based on flowpath did not produce distinct groups in some regions likely because groundwater flow paths can vary, or even reverse, over time within the same wetland (Siegel and Glaser 1987;Siegel et al 1995;Spence et al 2011). Although shallow flow paths in peatlands can be assigned using the presence or absence of inlet and outlet streams, these relatively small streams may have little effect on the overall hydrodynamics in a peatland (Spence et al 2011).…”

“…The HGM class Organic Soil Flat, for example, is described as bogs with predominantly vertical hydrodynamics, whereas the broad class Slope wetlands includes fens defined as having horizontal hydrodynamics (Smith et al 1995). However, peatlands frequently comprise a mosaic of bogs and fens exhibiting complex interacting hydrodynamics along both horizontal and vertical flow vectors (Ingram 1983;Siegel and Glaser 1987;Siegel et al 1995;Reeve et al 2001;Glaser et al 2004;Spence et al 2011). As a compromise, (Hall et al 2002) hybridized the two classes into a Slope/Flat type while developing the guidebook.…”

A graphical approach for documenting peatland hydrodiversity and orienting land management strategies

“…The hydraulic connectivity between wetlands also significantly influences runoff generation processes, especially in low relief areas such as the Boreal Plain of Canada (Devito et al, ). Spence et al () further stressed that the position of a wetland within a watershed influences its hydrological functions and that regional hydrological models of the boreal region should include an assessment of the position of wetlands within the hydrographic network (i.e., headwater vs. lower reaches). Overall, such studies reveal that climatic conditions and the intrinsic characteristics of peatlands and their position within the hydrogeological environment can influence runoff generation processes.…”