Built in the 1930s, Cheddar reservoir is a 1.1km diameter embanked reservoir south of the Mendips. Fed by water from Cheddar Gorge, it forms a vital part of Bristol Water’s supply infrastructure for the area, and it is planned to augment this infrastructure by building a second reservoir nearby.
MJ Rees worked with the consulting engineers for the project to design a bespoke topographic survey for the site, including the existing reservoir embankment and the area proposed for the new reservoir. Additionally, a survey of a 3.5km reach of the nearby River Cheddar Yeo was required, for the purposes of flood modelling.
To meet these requirements a 1:500-scale survey was undertaken, with high-resolution cross-sections at 100m intervals along the river. This survey was largely undertaken with network RTK GNSS, with high-accuracy total stations being used for areas within woodland and hard detail along highways. Network RTK is a relatively recent innovation, allowing installation of control in a fraction of the time taken using previous methods and permits GNSS survey work to be conducted without having to use a local base station, vastly improving work-rate efficiency on site.
