[ 2010-08-10 ]
The river flow is uncertain – particularly during monsoon transition months in all rivers and is true for Bhote Koshi river too. The river flow may spill from headworks discharging into river direct during the period. Bhote Koshi Power Company (BKPC) arranged for demonstration of warning sirens on January 31, 2010 targeting the communities in the river proximity stretching from the project’s head work to tailrace. The demonstration targeted to raise awareness in the community about flood related natural disasters, uncertain river flows and the safety measures thereof, The program was conducted at 6 different locations starting from Jhirpu School, moving on to Sri Chaur, 108 Kilo, Larcha, Guye Odar (between Larcha & Van Park), and ending at Van Park.

Two types of sirens are installed in the stretch - one for Glacier Lake Outburst Flood (GLOF) warning system and another for Spillway opening in the event of powerhouse shutting down. The GLOF warning system consists of two sensor stations at Friendship Bridge at Kodari border. In the event of GLOF, these sensors will transmit warning to other sirens installed in the downstream of the river including at Headwork, at Hindi village and warning cum monitoring stations at the powerhouse. Estimated time for GLOF to reach to headwork from Friendship Bridge is five minutes. The Spillway warning systems are manually operated and controlled from both the powerhouse and the headwork for respective locations. Warning sirens are sounded in the event of spillway opening that result in sudden flash flood downstream of Headworks. For safety purpose in both cases, the communities are advised to keep away at least 20m above the normal river bed level. Warning signs were installed at four different rivers crossing as suggested by the local community members who actively participated in the event.

Similar awareness program of the sirens warning was last conducted on 10th August 2007. Between the two periods an incident occurred whereby a person from Dumithang was swept along with his motorcycle by the rising river flow while crossing the river . Fortunately, there was no casualty by the flow, but it resulted in partial damage of his bike and sweeping away some of his belongings. BKPC is conducting such awareness campaigns at regular intervals to keep the community aware of changes in river flow and the risk of crossing the river at all times. It was also felt that due to increase in settlements along the river stretch the current Spillway warning siren system needs to extend its coverage area, and to increase its reliability. BKPC is currently seeking proposals from qualified contractors for this extension for earliest implementation.

Since the UBKHEP is a run-of-river project which only divert the river flow, and does not have a storage reservoir, BKPC is not able to control river flow if one or both units of the plant is shutdown. The Units can shutdown at any time due to system disturbances or faults thereby water flowing over the dam even if the gates are not opened, irrespective of controlled Spillway gate openings. The Spillway warning siren was installed at BKPC’s own initiative to caution local communities about such impending flows. The local communities need to understand that Sirens are a warning to stay away from the river in such cases and not to come to the river for fishing.
Crossing or fishing in the river at all times is risky and BKPC shall not be responsible for any such accidents. BKPC is not liable if people fail to take precautions, or willfully cross the river leading to such unfortunate accidents.