River restoration

This is an exciting time to be involved in river ecology. Not only is river restoration becoming more research focused but the river itself is now seen as a system directly connected to landscapes by numerous processes and feedbacks. These riverscapes are constantly interacting with landscapes through hydrological connectivity and interspecies relationships meaning that the river is an integral component of the wider ecology of a catchment. More than this the morphology, ecology and quality of a river is governed by processes that work at catchment scales. For example in the headwaters of a stream it is the hydrological flow paths emerging at the upper reaches of the landscape that govern instream flow rates, discharge, sediment and nutrient delivery, river morphology and finally in-stream ecosystems.

In the past this lack of spatial context has often resulted in restoration that fails due to rivers not being viewed as am emergent response of the catchment. Tackling eroding river banks is a case in point. Management and restoration has often focused on the immediate surroundings of the issue, such as putting in place buffer strips, shoring up or reprofiling the bank. This is despite eroding banks being a symptom of upstream processes such as soil compaction, drainage or deforestation which all increase the speed at which water reaches the channel network and thus the erosive power of a river.

Now that these connections are being made river restoration is becoming process orientated and thus more likely to be succesful. Whilst this is exciting it also poses numerous difficulties. One such issue is that working on one location can result in the need to work with multiple land owners (as the focus shifts to upstream processes) some of whom are more receptive then others. This requires skills that go beyond knowledge of river systems into social science and negotiation and may require teams of multi-disciplinary practitioners in order to develop plans and inform land managers. Where such teams are in place river restoration is becoming more succesful and populations of indicator species such as salmon and trout are becoming re-established.