Relation Of Engineering Failures To The Siltation History Of Reservoirs

The reservoir was equipped with a pumping system to lift the water to a reservoir at the highest point in town. The pipes were wooden pipes. The dam was equipped with a bottom outlet system (1 scour and 1 pipe outlets) located next to the left bank. A crane was installed at the dam crest to facilitate the outlet operation and to assist in clearing the outlet intake.

Flushing sediments were not successful. Indeed, the scour outlet system was small compared to other structures and its location is far from optimum. In particular, it does not compare with the large scour system of Illalong Creek dam built by the same organization and located less than 30km away. The reservoir become silted very rapidly and the siltation history was well documented by the Swedish researcher Hellstrom (1941). During the first ten years of operation, the silt was deposited at a rate of 49,000m3 per annum. The reservoir was 90% full in 1929, being filled primarily by suspended-load.

Several reservoirs became fully-silted rapidly including Cunningham creek dam. The latter was subjected. Such engineering failures might be related to a change in railway design organization in new south wales. This reservoir attributed sedimentation to several factors, including extreme climate conditions, ignorance of sediment processes, poor catchment and design mistakes.

Remedial actions suggested

Firstly it was suggested it was suggested that the catchment of the reservoir should be treated, this is basically a soil prevention measure for prevention of or minimizing sedimentation in the reservoir, then removing the sediments there after the continue the removal of the sediment using the hydro-aspirator from time to time.

When we consider about the Cunningham Creek dam which was built in 1912 has supplied water to the steam locomotives for main southern railway, this reservoir came up with rapid siltation with the annual rate of 49,000 m3 and 90% of the dam was fully filled in 1929. Siltation of reservoir may affect the safety of dam in adverse way by creating an extra heavy load on dam wall, Sediment materials are lead to streams due to soil erosion and water runoff from catchment areas. Before construction of a dam, it is very important to consider about the soil erosion and the sediment transportation processes of the catchment area and proper soil conservation practices must be introduced.

The failures of dams and reservoirs is great embarrassment for engineers and scientists in that country. Hence as upcoming civil engineers we have learnt a great lesson from the siltation of this reservoir about the things we need to consider before the construction of a reservoirs and the things we need to do after the construction such as the regular checks on the rate of siltation and how and what remedial actions to take in case siltation.