Ensuring dam safety at Koldam HPS: Safety compliances & statistical analysis

This paper elaborates the dam safety compliances being followed rigorously at Koldam HPS and conclusion of safe dam condition from the analysis of previous dam failure data. Koldam Hydro Power Station is NTPC’s flagship installation in the hydro sector. It is situated on river Satluj in district Bilaspur, Himachal Pradesh, India.

Koldam HPS is managing its operation and maintenance activities along with the compliances of Dam Safety Act 2021 with man megawatt ratio of approx. 0.1. In fulfilment of provisions of Dam Safety Act 2021, Dam safety unit at Kodam HPS is implementing the dam safety related assignment in true sense. A muti-disciplinary dam safety committee with diversified experienced minds has been set up for holistic-examination and resolution of dam safety related issues at site level. Pre and Post monsoon inspections are carried out with a systematic approach in full details and time bound manner. An SOP has been framed and implemented for regulating the frequency of magnitude and intensity of various inspections. Inspection of all components of dam complex and reservoir rim is carried out after every critical eventuality-e.g. high floods and earthquakes etc.

A comparative statistical analysis of dam failures across the globe is also presented in this paper. The failure phenomenon recorded in the historical data was compared with the parameters prevailing at Kodam e.g. most of the dam failures had occurred in the first two years after construction. Koldam is on-the safer side as it is approaching about 10 years of age. Several such comparisons were attempted with the statistical data regarding type of dam, age of dam, height and storage capacity of dam, Spillway capacity and modernization in design philosophy etc. Based on the Statistical analysis of dam failure data, it can be safely concluded that Koldam is truly safe in all the aspects.

In recent past, the frequency of dam failure related incidents due to inadequate spillway capacity and malfunctioning of hydro-mechanical equipment has been reported from across the world. At Koldam, due care has been taken in designing spillway capacity after detailed hydraulic and hydrological studies, and scheduled maintenance and testing of HM equipment is ensured; to avoid any such untoward event. Proactive measures for dam safety such as information sharing with people downstream of dam, keeping them aware about EAP/DMP, mock drill for safe evacuation, marking of danger water levels, displays at entry points along the river etc. are also summarized in brief.