When the downstream is ready
In the dry season, Bien Lac Lake is a true natural lake, with little water, despite its position as both a place to receive the natural flow of the lake basin (aquatic) and water from the Ham Thuan - Da Mi Hydropower Plant. According to the dry season water storage plan from the renovation and upgrading project, Bien Lac Lake will have 37 million m3 from the above two sources, but for many years, this amount of water has flowed into La Nga River through Lang Quang Bridge, not into Bien Lac - Ham Tan Canal, because the canal is higher than the water level of the lake. This canal is a channel to transfer water from La Nga River through La Nga Lake 3 to Bien Lac Lake, to provide production water for 1,500 hectares; supply water for industrial parks and clusters of 2,050 hectares for Ham Tan district; supply water for residential areas and services for the industrial park of 120,000 people.
Another canal also located downstream of Bien Lac Lake is the Song Dinh 3 Lake - Nui Dat Lake Water Transfer Canal. This canal supplies water to Tan Tien Water Plant; supplements irrigation water for 3 crops/year for 674 hectares of Nui Dat Lake irrigation area; expands the system to supply water to 1,200 hectares of dragon fruit and upland crops in Ham Tan district and La Gi town. However, even when Song Dinh 3 Lake completes phase 2 of water storage and completes the branch canal, it will not ensure the overall water supply of the project, so it is necessary to transfer water from the La Nga River basin to supplement.
In the original plan, by 2025, when La Nga 3 Lake is built by the Central Government, the province will also construct the Southern Inter-District Canal System consisting of 5 canals, including a route crossing Bien Lac Lake to transfer water to Ham Tan, La Gi, Ham Thuan Nam areas in 2 directions. The first direction, from La Nga 3 Lake through Ka Pet Lake, to Song Mong Lake to Du Du Lake and to Tan Lap Lake. The second direction, from La Nga 3 Lake down to Bien Lac Lake (transfer lake) to Song Dinh Forestry Lake, to Song Phan Lake, to Ta Mon Lake and then to Tan Lap Lake. However, up to now, the procedures for La Nga 3 Lake to be implemented have not been completed. The project to renovate and upgrade Bien Lac Lake has not been started. That means that every year, more than 225 million m3 of water from the basin will flow into the sea. Meanwhile, in the southern region of the province, despite having lakes such as Song Dinh 3, Nui Dat, Song Mong, Du Du..., there is still a serious water shortage in some places.
In mid-2024, the Provincial People's Committee held a meeting to listen to a report on the proposed investment policy for the Bien Lac Lake Renovation and Upgrading Project. In particular, it assigned relevant agencies and units to study and review carefully to clarify issues such as clearly identifying the water source for the lake in the dry season; water storage elevation, useful capacity needed to store water to ensure the task of supplying water to the downstream area according to the design, when the La Nga 3 Lake project has not been invested, what is the investment efficiency of Bien Lac Lake?
Will stabilize water in the south of the province
According to the analysis of the Department of Agriculture and Environment, if investment is made to renovate and upgrade Bien Lac Lake, it will have very important economic and social significance for the southern region of the province.
Because in the irrigation area of La Nga 3 Lake is 78,800 ha, the transfer through Bien Lac Lake is 41,890 ha; water supply of 300,000 m3/day and night for daily life, industry, tourism and services for the province, the transfer through Bien Lac Lake is 120,000 m3/day and night. Therefore, the investment in the Bien Lac Lake Renovation and Upgrade Project is to promote the effectiveness in providing additional water to Ham Tan and La Gi areas for industrial parks, daily life and agriculture in the dry season, while waiting for La Nga 3 Lake.
Accordingly, the investment in the Bien Lac Lake Improvement and Upgrade Project is divided into 2 phases. Phase 1, with the goal of improving and upgrading Bien Lac from a natural lake into an irrigation lake to regulate water sources from the La Nga River basin (with additional water discharge from Ham Thuan - Da Mi Hydropower Plant) to the Dinh and Phan River basins; promoting the objectives of the Bien Lac - Ham Tan water supply canal; supplementing water to the upstream of Dinh 3 River Lake to supply water to the water transfer canal system from Dinh 3 Lake - Nui Dat Lake, Ham Tan District and La Gi Town; supplementing water for the industrial park in Ham Tan District and La Gi Town. At the same time, when storing water from Bien Lac Lake in the dry season, it also creates conditions for pumping irrigation around the lake in Duc Linh and Tanh Linh districts, contributing to changing the crop structure in this area. In addition, it also contributes to the stable development of aquaculture, fishing and ecotourism development...
As for phase 2, after La Nga 3 lake is built, with the goal of investing in completing the project to ensure sufficient water level to transfer water not only to Ham Tan, La Gi, Ham Thuan Nam areas but also to the area of 3 communes in the south of Duc Linh district through Bien Lac - Tan Ha canal according to the plan, extending to Xuan Loc district, Cam My, Dong Nai province in the irrigation area of La Nga 3 lake.
According to the leader of the Department of Agriculture and Environment, after the Provincial People's Council adjusted the investment policy of the Southern Inter-District Water Supply Canal System to a temporary halt, the Bien Lac Lake project, which is included in the Binh Thuan Provincial Planning for the period 2021 - 2030, with a vision to 2050, should soon be implemented in accordance with investment procedures to store water for people's lives and develop the economy in the southern part of the province. The total estimated investment of the project is more than 1,422 billion VND, most of which is compensation for the area of the reservoir. However, according to preliminary economic efficiency calculations, it is expected that after 15 years of operation, the project will recover its capital.
The natural lake Bien Lac has a fairly abundant water source located at a high altitude, so the lake has a favorable water supply control elevation, making it easy to receive water. If it is converted into an irrigation lake, the cost will be the lowest compared to newly invested lakes, so using Bien Lac Lake to regulate the water source of La Nga River, supplying water to the southern region of the province will be the most effective solution.
Source: https://baobinhthuan.com.vn/50-nam-tri-han-cua-binh-thuan-suc-manh-ho-bien-lac-khi-duoc-nang-cap-131091.html
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