Inter-reservoir operation in the Ca River basin: Harmonizing interests

(Baonghean) - For the first time, Nghe An has taken on the task of commanding the flood discharge operation of the Ban Ve and Khe Bo Hydropower Reservoirs. This is a huge responsibility. However, with the timely participation of relevant levels and sectors, and regulations on assigning tasks to implementing units, the initial results have shown effectiveness in the operation of inter-reservoir flood discharge.

Previously, Ban Ve and Khe Bo Hydropower Plants applied the reservoir operation process approved by the Ministry of Industry and Trade, in which the priority order was: Construction safety - Power generation - Flood control for downstream areas. Because the goal of power generation was more important than flood control for downstream areas, and the process applied the operation of a single reservoir, there were times during the implementation that flood discharge caused flooding and damage to downstream areas... Therefore, on August 11, 2014, the Prime Minister issued Decision No. 1337/QD-TTg, promulgating the Inter-reservoir Operation Process on the Ca River Basin during the annual flood season. In which, the priority order was changed to: Ensuring construction safety - Flood control for downstream areas - Power generation; and assigned Nghe An province to directly command the operation of flood discharge for the inter-reservoir of Ban Ve and Khe Bo Hydropower Plants.

Ban Ve - Tuong Duong Hydropower Dam Project

Mr. Hoang Hieu - Deputy Director of the Department of Agriculture and Rural Development, Chief of Office of the Provincial Steering Committee for Flood and Storm Control said: “This is the first time Nghe An has been assigned the task of commanding the operation of flood discharge between the Ban Ve and Khe Bo Hydropower reservoirs, so it requires great responsibility. However, practical experience is not much, so the Provincial People's Committee assigned the Steering Committee for Flood and Storm Control to coordinate with relevant levels and sectors to develop an implementation plan and draft the assignment of tasks for relevant units to implement. With active participation, relevant levels and sectors have contributed many practical ideas. Currently, we have completed the regulations on assignment of tasks to units".

Taking on important responsibilities in commanding the operation of the inter-reservoir flood control is the Office of the Provincial Flood Control and Search and Rescue Steering Committee. In addition to advising the Provincial Flood Control and Search and Rescue Steering Committee and the Provincial People's Committee on the operation and regulation of Ban Ve and Khe Bo reservoirs, it is also responsible for inspecting and supervising the implementation of reservoir operation orders and notifying relevant levels and sectors; in case of unusual incidents, it must be promptly reported to ministries and sectors for direction on handling measures... According to the province's assignment of tasks, the North Central Hydrometeorological Station will strictly implement the regime of monitoring, forecasting, providing information, consulting on calculating the total value of flood reduction, flood discharge volume and determining the water level of the reservoir receiving the flood, and the time of flood discharge. Along with that, the Director of Ban Ve Hydropower Company, Vietnam Electricity Development Joint Stock Company (Khe Bo Hydropower) is responsible for implementing the reservoir operation orders in accordance with regulations. Relevant departments and branches such as: Agriculture and Rural Development, Industry and Trade, Natural Resources and Environment, Information and Communications, downstream districts... based on their specific functions and tasks, coordinate to synchronously implement tasks related to operating procedures, flood reduction, and overcoming consequences of flood discharge...

Mr. Nguyen Quoc Toan - Deputy Director of Ban Ve Hydropower Company said: "The total capacity of Ban Ve Hydropower Reservoir is more than 1,834 million m3, the normal water level is 200 m and according to regulations, the highest water level before the flood of the reservoir during the flood season is 192.5 m. In normal weather conditions, the company proactively operates and regulates, ensuring that the water level in the reservoir does not exceed 192.5 m and when there is an emergency storm, tropical depression near the shore or weather that is likely to cause rain and floods that in the next 24 - 48 hours are likely to directly affect localities in the Ca River basin, the Head of the Steering Committee for Disaster Prevention and Control and Search and Rescue of Nghe An province decides to operate the reservoir. Following this procedure, on September 23, the upstream water level at Ban Ve Hydropower Reservoir only reached 199.48 m (50 cm lower than the normal water level), the flow to the reservoir is about 550 m. m3/h, the Provincial Steering Committee for Flood and Storm Control has directed the plant to discharge a total volume of about 460 m3/h, of which, discharge through the generator is 300 m3/h, discharge through the spillway with a flow of 160 m3/h". Khe Bo Hydropower Plant has also strictly followed the inter-reservoir operation process. Mr. Do Van Manh - Deputy Director of Khe Bo Hydropower Plant said: "The total capacity of Khe Bo Hydropower Reservoir is 97.8 million m3 and has a normal water level of 65m. During the process of Ban Ve Reservoir participating in cutting and reducing downstream floods, Khe Bo Reservoir operates to regulate the discharge flow equal to the flow to the reservoir. Therefore, recently Khe Bo Hydropower Plant discharged about 800 m3/h equal to the amount of water coming in". It is known that Khe Bo Hydropower Plant also has to regularly coordinate closely with Nam Mo Hydropower Plant to operate the reservoir properly.

The coordination between the Provincial Steering Committee for Flood and Storm Control and the two Hydropower Plants in the past time has shown clear effectiveness in the operation of the inter-reservoir. According to Mr. Hoang Hieu - Chief of Office of the Provincial Steering Committee for Flood and Storm Control, "The province's proactive ordering of the operation of inter-reservoir works in situations of rain and flood will find the most beneficial solution to limit damage to the downstream in limiting artificial floods when releasing floodwaters, harmonizing the interests between the locality and power generation; at the same time, retaining water in the dry season. However, in order to effectively carry out the command and operation of inter-reservoir works, in the coming time, coordination and drills between relevant levels, sectors and people in the downstream area will be strengthened. At the same time, investing in modern equipment and machinery for hydrological work and increasing human resources...". To serve the command and operation of inter-hydropower reservoirs and the synchronous and timely coordination between relevant levels and sectors, as well as in the downstream area, the province has supported 100 million VND to pilot the application of providing information via the messaging system of the Telecommunications sector...

However, the current concern regarding the operation of the inter-reservoir in the Ca River area is that there is only an operating procedure for the rainy season, but there is still no operating procedure for the dry season. Mr. Phan Van De - Deputy Director of the Department of Agriculture and Rural Development said: "The Ca River originates from Laos, so it is very complicated to grasp information about water flow and weather developments in the dry season. Therefore, if there is no inter-reservoir operating procedure, the downstream area in the dry season will face difficulties in water resources for production and people's daily life. Currently, the Department of Agriculture and Rural Development is guiding irrigation companies and downstream districts to give their opinions on the draft operating procedure for the inter-reservoir in the Ca River basin in the dry season".

Article and photos:Hoang Vinh