Floating 'water bombs' in the rainy and stormy season

(Baonghean) - Nghe An has over 650 dams, many of which were built a long time ago and have deteriorated. Due to limited funding, annual repairs are only temporary. Difficulties overlap each year, and until this year's storm season, dam safety continues to be a major concern for authorities at all levels and people in some localities.

Don Hung Lake (Hung Thanh commune, Yen Thanh).

Many dams are "old and weak"

For many years, hundreds of households in Hung Thanh commune (Yen Thanh) have always felt insecure about the safety of Don Hung dam every time the storm season comes. Mr. Phan Quang in hamlet 6 near the dam body area worriedly said: "Every time the flood season comes, the dam water rises, so we have to proactively move our belongings to another hamlet to be on guard...".

Through observation, we found that the dam body is quite thin, the breakwater is cracked, and many sections have been infested with termites. Mr. Tran Van Trung - Chairman of Hung Thanh Commune People's Committee said: During the flood season, if an incident occurs at Don Hung dam, it will directly affect the safety of 6 hamlets, with over 700 households, especially hamlets 5, 6, 7, 8 located in the middle of the dam area. In the flood season of 2014, the flood water rose high, and the Bac Irrigation Company Limited had to use measures to break the spillway to protect the dam from breaking. Every year, the company also fixes the problem; opens more spillways, repairs landslides, builds the dike roof, raises the dam body... However, it is still difficult to feel secure.

Don Hung Lake, Hung Thanh Commune (Yen Thanh) was built in 1973 with a capacity of over 5.4 million m3 of water, irrigating 380 hectares and providing water for daily life and flood prevention for people in 4 communes: Hung Thanh, Hau Thanh, Lang Thanh and Tien Thanh. Up to this point, the lake has seriously degraded, the dam body has sunk in many places, causing cracks in the wave-breaking wall and the downstream rock roof.

Bac Irrigation Company Limited is located in the district and manages 17 large and small dams in 4 districts: Do Luong, Yen Thanh, Dien Chau, Quynh Luu. Currently, only 10 reservoirs have been upgraded. The remaining dams have not been upgraded, and the risk of dam failure when the flood season comes is very high.

In Yen Thanh district, there are many locally managed dams in a state of disrepair. Thi Long reservoir in Quang Nhan hamlet, Quang Thanh commune (Yen Thanh) has a capacity of about 700,000 m3 but is mainly made of earth. This dam once broke, causing flooding for many households in Quang Nhan hamlet, and more dangerously, it poured water into Ve Vung lake, threatening the large dam of Ve Vung lake.

In Quynh Luu district, Khe Gang reservoir with a capacity of 1 million m3 of water in Ngoc Son commune, built in the 1970s, is now seriously degraded. Mr. Van Bai in hamlet 4A, Ngoc Son commune shared: During the flood season, villagers stay up all night, and when the water rises close to the dam body, they have to evacuate to another hamlet to take refuge. Mr. Ho Van Lap - Chairman of Ngoc Son commune People's Committee added: In 2005, Khe Gang reservoir was flooded and the dam bank collapsed. In 2006, the commune received financial support from the State to "patch" the downstream and upstream banks. However, the dam body is weak and gradually becomes thinner.

Ho Thanh Dam with a capacity of 10 million m3, in Nam Kim Commune (Nam Dan), built in 1961, serving irrigation for hundreds of hectares of rice, has also leaked many times. Khe Da Dam in Nam Loc Commune (Nam Dan), in 2013, prolonged heavy rains, the overflow of Khe Da Dam caused flooding in the downstream area, affecting nearly 250 households and schools in Nam Loc Commune.

Officers of the Northern Irrigation Company Limited inspect the dam body of Don Hung lake.

Proactively handle construction incidents

In fact, when a reservoir bursts in the localities under their management, some localities are very confused in the response phase. A typical example is the Tay Nguyen reservoir (Quynh Thang commune, Quynh Luu) with a capacity of 1.2 million m3, irrigating over 200 hectares, built in 1966, and repaired and upgraded in 2009. The project was assigned to the Quynh Thang Agricultural Service Cooperative for management. This unit assigned the protection and operation of the sluice gates to a private individual without any training on the use and operation of the reservoir, leading to the reservoir burst in September 2012.

Restoring upstream forests to both preserve water resources and reduce the massive water flow into the reservoir during the rainy and flood season, which can potentially cause dam failure. When constructing and upgrading reservoirs, it is necessary to construct and fill the correct cross-section, design, upgrade the spillway to have enough flow, and handle seepage, leakage, and termite nests to minimize the risk of dam failure... these are tasks that require technical knowledge and qualified legal entities to undertake.

The province currently has 625 large and small lakes and dams. Of these, irrigation companies only manage 60 lakes and dams with a capacity of over 1 million m3, the rest are managed by localities. 48 large-capacity lakes and dams out of a total of 60 have been upgraded to ensure safety before the storm season. In 2015 alone, the central budget invested over 500 billion VND for the province to build and renovate irrigation works such as canals, spillways, river dykes, and lakes and dams. And most recently, the ODA project continued to support over 100 billion VND to invest in and upgrade 5 weak lakes and dams. These works will be implemented next month.

Ho Quan Hai in Phuc Thanh commune (Yen Thanh) is being upgraded.

Mr. Pham Huu Van - Deputy Head of the Irrigation Department of Nghe An province said: The current solution is to direct localities to proactively handle construction incidents; waiting for capital will take a long time and the construction can have dangerous incidents at any time.

Mr. Phan Van Tuyen - Chairman of Yen Thanh District People's Committee: Yen Thanh has over 200 small dams, irrigating over 3,000 hectares of rice concentrated in the communes of Minh Thanh, Quang Thanh, Thinh Thanh... From 2010 to now, with the source of Government bonds, the district has only upgraded and repaired 14 small dams, the rest are due to the localities' own rudimentary maintenance and repair, so most of them are degraded, with a very high risk of dam failure.

Van Truong