What are the bases for determining minimum flow in Vietnam in 2024?
What are the bases for determining minimum flow in Vietnam in 2024?
Pursuant to Clause 4, Article 24 of the Law on Water Resources 2023, bases for determining minimum flow are composed of:
- Hydrological characteristics, flow regime and functions of water sources; status and demands for exploitation and use of water resources;
- Requirements for protection and prevention of deterioration, depletion and pollution of water sources; protection and conservation of aquatic ecosystems and biodiversity; natural disaster management; assurance about national defense, security and other requirements related to water source protection;
- Scale, scope of impact, exploitation method and ability to regulate water for dams and reservoirs;
- International agreements and treaties related to water resources with countries sharing water sources to which the Socialist Republic of Vietnam is a signatory.
Pursuant to Clause 3, Article 4 of Circular 64/2017/TT-BTNMT, the comprehensive consideration of the following factors is required to determine the minimum flow at each location for suitability:
- Hydrological characteristics, flow regime, flow distribution in rivers and streams, water contribution ratio of rivers and streams in the river system, and the functions of the water source.
- Current status and water utilization needs of water exploitation and direct water use on rivers and streams.
- Requirements for protection and prevention of water depletion, water source depletion, and meeting minimum water usage needs in cases of drought, severe water shortage, requirements for protection and conservation of aquatic ecosystems, biodiversity, national defense, security, and other requirements related to water source protection.
- Scale, scope of impact, exploitation methods, arrangement of project items, and water regulation capacity for reservoirs.
- Provisions of international conventions to which the Socialist Republic of Vietnam is a member, in cases related to transboundary water sources.
What are the bases for determining minimum flow in Vietnam in 2024? (Image from the Internet)
What are the locations for determining minimum flow in Vietnam?
Pursuant to the provisions of Article 6 of Circular 64/2017/TT-BTNMT, the minimum flow is determined for specific locations on rivers, streams, or downstream of reservoirs and is implemented as follows:
(1) For rivers and streams:
- The position for determining the minimum flow rate on rivers and streams is at the river or stream mouth before it joins another water body. If there is a hydrological station on the river or stream that represents the flow regime, the hydrological station is chosen as the position to determine the minimum flow rate.
- In addition to the designated positions above, if there are specific requirements to ensure water exploitation, water use, cultural, sports, or tourism activities, or requirements for the protection of aquatic ecosystems, biodiversity, economically valuable aquatic species on one or more sections of the river or stream, the competent state agency shall consider and decide on additional positions to determine the minimum flow rate as stipulated in Article 9 of this Circular.
(2) For reservoirs:
- The position for determining the downstream minimum flow rate of a reservoir is immediately after the dam. If there is a hydrological station controlling the flow regime of the reservoir downstream, the hydrological station is chosen as the position to determine the minimum flow rate. The minimum flow rate at this position includes the regularly and continuously maintained minimum flow rate, as well as the minimum flow rate appropriate to the requirements of the regime and the time of water use downstream.
- For reservoirs that interrupt the flow of rivers or streams, in addition to the designated positions mentioned above, the minimum flow rate must also be determined immediately after the project item that restores the flow into the river or stream or immediately after the hydropower plant. The minimum flow rate at this position is maintained in accordance with the requirements of the regime and the time of water use downstream.
Vietnam: What are the cases in which minimum flow has to be determined under the Law on Water Resources 2023?
Pursuant to the provisions of Clause 18, Article 2 of the Law on Water Resources 2023, “minimum flow” means a flow at the lowest level necessary for maintaining a river or river section in order to assure the normal development of aquatic ecosystems and maintain a minimum level for the exploitation and use of water.
Pursuant to Clause 1, Article 24 of the Law on Water Resources 2023, cases in which minimum flow has to be determined:
- Rivers and streams in which water transfer structures, large dams, reservoirs and water exploitation structures exist, potentially affecting people's livelihoods, socio - economic development, and aquatic ecosystems.
According to local resources and conditions for socio - economic development, importance of water sources, requirements for natural disaster management and requirements for water source protection, the competent authority specified in clauses 6 and 7 of this Article shall decide the order of priority, locations where minimum flow needs to be maintained on each river or stream for which minimum flow needs to be determined.
- Dams and reservoirs built in rivers and streams, except for the dams and reservoirs which have been put into operation, making it unable to adjust or add any minimum flow discharge structure item.
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