Talk, International Conference of River Restoration and Maintanance 2016, Krakow, Poland: 2016-09-20 - 2016-09-23
Abstract:
The hyporheic zone is an area of ground-surface water mixing within the bed and banks of rivers. It plays an important ecological role as a habitat and region of biogeochemical cycling, and is believed to support water quality improvement (e.g. nutrient and toxin removal). Therefore, a functioning hyporheic zone may be an important component to sustainable river restoration. However, before recommending hyporheic restoration measures, we first need to establish what factors influence the presence and hydraulic functioning of the hyporheic zone, and how existing stream and catchment-scale restoration measures interact to have a cumulative impact. In this study we outline a physical-based framework that links hydrological and geomorphological attributes of the river system to potential hyporheic exchange at a restoration site. From larger to smaller scales, the hyporheic exchange is related to hydroclimatic, hydrogeological and topographical variables that differently enhance or constrain the hyporheic functioning. The framework was developed based on a conceptual understanding of surface-groundwater interactions from recently published reviews, supported by previous studies on hyporheic exchange. The framework was developed and tested by using a range of topographical, geological and hydrological data across restored and unrestored rivers in the UK. Although hyporheic functioning is influenced by numerous variables, multivariate techniques identified the key factors that make the most profound impact on hyporheic exchange. The outcomes of the study directly benefit both our conceptual understanding of the drivers of the hyporheic exchange, and how they interact across spatial and temporal scales. Also it provides a method to preliminarily predict hyporheic exchange and raising the opportunity for targeting restoration sites, methods and criteria for maximizing hydrological and ecological benefits. Finally, the hierarchical approach of the framework would help restoration practitioners approaching the hyporheic zone for a cross-scale perspective, with possible catchment-scale solutions to reach-scale problems.