Improving the watertightness of Winscar Reservoir

Leakage has been a problem at Winscar dam since it was filled for the first time in the late 1970s. Supplementary foundation grouting was carried out as well as repairs to the upstream facing of dense asphaltic concrete at that time and the reservoir was operated without major problems for 20 years. A pattern of rising seepage was observed during late 2000, which eventually led to the appearance of a large spring at the downstream toe six months later. This paper describes the investigation of the leak and outlines the actions taken to improve reservoir watertightness. A geocomposite liner was installed over the upstream face and the grout curtain was reinforced. Early results show that these works have been effective in reducing water losses.

• INTRODUCTION

• INVESTIGATIONS INTO THE CAUSE OF THE NEW LEAKAGE

• PROCURING AN ENGINEERING SOLUTION

• DESIGN AND CONSTRUCTION OF THE GEOCOMPOSITE LINER

• REINFORCEMENT OF THE GROUT CURTAIN

• MONITORING DURING REFILLING OF THE RESERVOIR IN 2002

• CONCLUSIONS

• REFERENCES

• ACKNOWLEDGEMENTS