Assessment of the Impact of the Spatial Distribution of Isolated and Riparian Wetlands on Watershed Hydrology using a Mathematical Modelling Framework

Abstract:

Wetlands play a significant role on the hydrological cycle, reducing peak flows through water storage functions and sustaining low flows through slow release of water. However, their impacts on water resource availability and flood control are mainly driven by wetland types and locations within a watershed. So, despite the general agreement about these major hydrological functions, little is known about their spatial and typological influences. Consequently, assessing the quantitative impact of wetlands on hydrological regimes has become a relevant issue for both the scientific community and the decision-maker community. To investigate the hydrologic response at the watershed scale, mathematical modelling has been a well-accepted framework. Specific isolated and riparian wetland modules were implemented in the PHYSITEL/HYDROTEL distributed hydrological modelling platform to assess the impact of the spatial distribution of isolated and riparian wetlands on the stream flows of the Becancour River watershed, Quebec, Canada. More specifically, the focus was on assessing whether stream flow parameters, including peak flow, low flow and flow volume, were related to: (i) the percentage and the distribution of wetlands in the watershed, (ii) geographic location of wetlands, and (iii) seasons. Preliminary results suggest that: (i) integration of specific wetland modules can slightly improve HYDROTEL’s ability to replicate basic hydrograph characteristics; and (ii) isolated and riparian wetlands have individual space- and time-dependent impacts on the hydrologic response of the study watershed.