The works at Gouthwaite have been required to bring an excellent example of Victorian engineering and heritage in line with modern safety standards. Gouthwaite Reservoir possesses the largest dammed catchment in Yorkshire, totaling 115km2; approximately 1% of Yorkshire. The ramifications of this is that given the catchment size, the flows the channel is required to withstand are greater than any other spillway the region. The safety standards require that the dam is safe under even the maximum possible outflows (PMF), which for Gouthwaite is around 920m3/s; equivalent to the daily peak flow of the River Tyne.
This project has required the delivery of an efficiently designed and executed construction to minimise disruption to; stakeholders, the construction programme and risk to the project. The reservoir is situated in the Nidderdale AONB and a SSSI, requiring works to of the highest quality. The works have taken place under the dam’s overflow and given the catchment size and lack of control the water levels this has led to a significantly reduced protection when compared with standard reservoir safety works. Should the reservoir overflow there is a risk that the works
could have been destroyed and the dam’s support exposed. The work has been required to minimise impact on the SSSI of the reservoir, reliability and quality of compensation water to the River Nidd; a main river which holds significant ecological, commercial, social and sporting value. Added to this was the requirement to compensate at all times as dictated under an Act of Parliament.