In the past few decades, approaches to the restoration of rivers have increased enormously in scope and sophistication. Although the vast majority money spent on river management is related to what is seen in the UK as a very ‘traditional engineering enterprise’,
The value of multi-disciplinary and multipurpose intervention in river works in now apparent (Whelan, 1991).
Modern approaches to river systems and restoration increasingly stress the multiple forms of coupling between river flows and ecology (Clifford, 2011). The flow regime is regarded by many aquatic ecologists to be a key driver of river and wetland ecosystems (Bunn and Arthington, 2002), and Bunn and Arthington (2002) now claimed there to be an increasing awareness of the pivotal role flow regime as a key driver of the ecology of rivers and their associated floodplain habitats (Bunn and Arthington, 2002). Indeed, a new science of eco-hydraulics or eco-hydrology is now developing where all attributes of the flow hydrograph – once interpreted purely from a water resource or geomorphological (channel forming) perspective – are seen to have ecological potentials and controls. Represent, perhaps, the newest paradigm in academic and practitioner literature dealing with river restoration, eco-hydrology have become more prominent in the international scientific literature over the last decade. Such a paradigm can be seen to represent an attempt to have a move towards a holistic view of the way in which rivers and managed, whilst still trying to identify a fundamental science (and thus providing a foundation for the sustainable management of water resources; Hannah et al., 2007).
, claimed by Hannah et al. (2007) to have been stimulated by a wider realization of the need for ‘hybrid science’ and inter disciplinary approaches.
River flows show marked variability in time and space (Poff, 2002) and the Eco-hydrology paradigm ultimately rests upon the assumption that such variation of river flows have both direct and indirect controls on the character of aquatic biodiversity. In particular, these controls operate over a series of nested and hierarchical feedback systems (the fluvial hydrosystem; Petts and Amoros, 1991) and thus require, as a response, a form of holistic streamflow management.
To date, the identification of minimum flows required to maintain aquatic and riparian species at critical stages of their lifecycles has represent the most popular hydrological determinants in restoration efforts, but simplistic formulae developed for low flows miss the important of periodic (hydrological) disturbances (Borschardt, 1993). More recent approaches thus strive to incorporate these disturbances (both forced and cyclic events) into channel designs and modified