New solutions for remote monitoring of pre-cast concrete service reservoir and sludge lagoon

Abstract

The use of distributed temperature and/or strain measurements for embankment and reservoir monitoring has grown in recent years. The paper elaborates on two different methods applied through two installation examples in the UK. To reduce risk, a leakage monitoring system using distributed fibre optic temperature sensing (DTS) with a spatial resolution of 0.7 m has been installed at the newly constructed 45ML Hanchurch Service Reservoir. The gradient method provides information regarding possible seepage by monitoring absolute temperatures over time. Heat pulse method consists of measuring the temperature changes over time using DTS following heating the hybrid cable with a known electrical power input. Central to the £7 million investment on the century-old Curdworth sludge lagoon is the installation of a novel combined leakage and movement of the early detection system. The system is based on distributed fibre optic sensing methods for measuring strain and temperature, both fully automated with a time resolution of about an hour. Instrumentation can be analysed in real time. Trigger levels are being established during a trial period, linked to an automatic alarm system, which supplements site-based surveillance. This will facilitate the early detection of potential embankment/reservoir integrity issues and, in turn, will enable prompt action to be taken to reduce risk and in an extreme case the implementation of essential repairs in order to prevent a dam failure.