Modifications and degradation of habitats

River Channel Modifications

The River Kennet, like most chalk rivers in England is a highly physically modified system

Recent modifications (particularly dredging and channel widening for land drainage or agricultural purposes) have had detrimental impacts on river ecology and navigation.

In urban and sub-urban areas the river is often channelised with no marginal vegetation. Historic structures, for example mill hatches, can impact the river, by impounding upstream sections and obstructing fish passage. The Environment Agency (EA) Water Level Management Plans for the SSSIs on the Kennet and Lambourn identify all these structures and their adverse impacts, and prioritise actions required to address these impacts.

Habitat restoration strategy

The EA’s Kennet Habitat Restoration Strategy identified those reaches of the catchment where morphological restoration and/or improvements to fish passage were deemed to be most important in order to assist recovery to favourable condition for the River SSSIs, and to move towards ‘good ecological status’ under the Water Framework Directive. The Strategy was based on outputs from various studies including relevant Water Level Management Plans, a Kennet Fluvial Audit, River Habitat Surveys, and the in-house knowledge of Fisheries and Conservation staff in regard to the most degraded sections of river.

In order to meet the requirements of recent guidance on the content of SSSI restoration strategies a “whole river restoration plan for the River Kennet and River Lambourn SSSI” has been produced in partnership with Natural England. This plan provides a strategic ‘whole river’ approach to river restoration based upon identifying key habitat features, linking fluvial geomorphology, ecology, and phased implementation of restoration works that encourage assisted natural recovery. This plan is in its infancy, so the timing and extent of any future restoration work is subject to feasibility, funding and landowner agreements.

River restoration work

The programme of river restoration work should be seen in the light of much that has already been achieved in the Kennet, by Action for the River Kennet, EA, Natural England, landowners and fishery interests over the last 15 years or so. It is not possible to predict what scale of work will be required to achieve ‘good ecological status’ under the Water Framework Directive or even favourable condition for the SSSIs. This will become evident once the results of improvements are seen.