Water, water everywhere?
WHAT ARE THE best methods to ensure that canal water supplies keep pace with demand over the next 35 years in the face of possible increases in usage, climate change and new legislation? That is the question that a Water Resources Strategy launched by the Canal & River Trust will be aiming to answer between now and 2020.
The strategy is a five-year plan which will: Define a target ‘level of service’ whereby canals shouldn’t be closed (or reduced to lower than five hours’ opening per day) by a drought more often than once every 20 years (known as a five percent probability), and assess which parts of the system do not achieve that level. Assess the potential impact of climate change (using water companies’ modelling); possible funding shortages resulting in increasing leakage; new legislation (for example the need to apply to the Environment Agency for abstraction licences when the current exemption runs out), and increased boating. Identify all possible ways of saving water or securing extra supplies, estimate their benefits in megalitres per day against their costs, and identify which ones represent the best value. Plan a schedule so that for any given ‘hydrological unit’ (a waterway or number of waterways supplied by the same sources) the proposed improvements will be implemented just before it falls below the five percent threshold. Implement the schedule over the following 30 years.
Some proposals have already been made: for example, no permission for new marinas if they would mean extra usage that would breach the five percent threshold; assessment of restoration schemes for impact on existing supplies; prioritisation of lock gate replacement based on water impact rather than just on condition.
In addition, two areas have been identified for detailed study. All existing out-of-use water-saving sideponds are to be recorded and assessed to estimate their possible contribution to water saving if used correctly ( perhaps under supervision of volunteer keepers) or wastage if used wrongly. And dredging will be looked at from a water-saving point of view: not just normal main-line and spot dredging, but also specific sites where extra depth could help – such as summit levels, as was often historically the case. See canalrivertrust.org.uk for the full report.