Geophysical Investigation | Damflask Reservoir, Sheffield

Client: Mott MacDonald Bentley, on behalf of Yorkshire Water

Project:  Damflask Reservoir Remediation

Completion:  2016


Met Consultancy Group was employed as Geophysics Contractor to undertake an extensive geophysical investigation of the reservoir structure.

Project Overview

Situated in the Peak District National Park, Damflask Reservoir was completed in 1896 to supply water to the population and industries of Sheffield. The reservoir has a capacity of 1,123 million gallons with a surface area of 47 hectares and is now undergoing an £800,000 spillway improvement project managed by Engineering specialists, Mott MacDonald Bentley.  A spillway is an overflow structure used to control water flows into the area downstream of the reservoir when the reservoir is full. It allows floodwater to pass in a safe and controlled manner downstream so water does not overtop the dam.

Prior to improvement works commencing, Met Consultancy Group was employed as Geophysics Contractor to undertake an extensive investigation of the reservoir structure to identify if any voiding existed within the spillway and tumble bay, and to provide a ground profile model of the rockhead below the spillway and tumble bay.

 Technical Overview 

Met undertook investigations of this remote site using ground penetrating radar and provided a report and drawings detailing the location and characteristics of voiding found; along with a ground profile model of the bedrock below the spillway and tumble bay.  Works involved a range of different GPR antennas and frequencies to provide the required resolution.

Fall prevention measures were required for works to the spillway areas as these feature sloped and stepped surfaces with a gradient of up to 1 in 7.  Works on this challenging project were delivered on time and within budget, successfully identifying areas for remediation and informing the spillway improvement project which will extend the use of this important water infrastructure.

Jordan Langbridge, Yorkshire Water Project Manager said; “The work will ensure that the spillway continues to carry out its role of protecting the reservoir embankment from flood erosion by safely diverting excess water flows away from the site.”