Nghe An: Severe drought and saltwater intrusion threaten summer-autumn production
(Baonghean) - The intense heat since the beginning of the season has caused many dams in Nghe An to run out of water. The risk of severe drought and saltwater intrusion are worrying realities that require urgent solutions to prevent and combat right from the beginning of the summer-autumn crop.
Many dams do not hold enough water.
Before the summer-autumn crop, the water level in Khe Dua Lake (Thai Hoa Town) is currently less than 50% of its capacity. With a capacity of 0.5 million m3The lake is responsible for providing irrigation water for 60 hectares of rice in Nghia Thuan commune.
Mr. Hoang Tran Lam - Director of Phu Quy Irrigation Company Limited is concerned: Not storing enough water, water sources falling lower than the average of many years is a common situation of many dams in the area even before entering the peak period of providing irrigation water for summer-autumn production.
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| Ve Vung reservoir in Dong Thanh commune (Yen Thanh) is dry, even some areas of the lake bed have green grass. Photo: Van Truong |
If there is no additional rain in the coming time, it will be very difficult to ensure enough water for production, because when the water source drops below the dead water level, there will be no way to supplement the water source to irrigate the dry rice fields.
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| In the 2019 summer-autumn crop, many areas in Nam Dan had to harvest early due to crop failure caused by drought. Photo: Phu Huong |
Nghe An currently has more than 1,060 dams, 615 pumping stations and 5,950 km of canals. Of these, enterprises manage 96 lakes and localities manage 965 lakes. As of May 8, of the 96 lakes currently managed by enterprises, only 1 lake is full of water. The number of reservoirs with a capacity of 50% - over 70% is much smaller, while the number of lakes with water below 50% of the design capacity is 39. Meanwhile, 965 small reservoirs managed by communes and cooperatives all only reach 50% - 65% of the design capacity. The water level at key works such as the upstream of Nam Dan sluice, Nghi Quang sluice (Nghi Loc) ... are all lower than the design water level; Ban Ve lake is in a similar situation.
According to Mr. Nguyen Truong Thanh - Head of the Irrigation Sub-Department, with the current water resources situation and meteorological and hydrological forecast information, if the weather in the coming time is unfavorable for agricultural production, with no rain, hot weather and early southwest winds, drought will occur on a large scale. In particular, this year has two Aprils (lunar calendar), so the drought situation is forecasted to be more severe.
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| Many items at Nghi Quang bar have seriously degraded, not meeting the requirements of preventing salinity and preserving freshwater. Photo: Phu Huong |
Preventing the risk of saltwater intrusion
Bara Ben Thuy has the function of preventing salinity, preserving fresh water, draining waterlogging and preventing floods for more than 3,000 hectares of rice in the Nam - Hung - Nghi region. For the past 5-7 years, salinity has penetrated early in the spring crop due to low rainfall, and from April and May the water level in the fields has dried up.
“We strictly follow the operating procedures, regularly check the quality of water sources, and block off locations with saltwater to minimize saltwater intrusion. This year, the salinity has increased, and since the beginning of May, the downstream area has been salty, so every morning and afternoon we have to measure the salinity concentration at many different points to get accurate results, and recommend that people use water reasonably to minimize the harmful effects of saltwater intrusion.”
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| Ben Thuy Bara has the function of preventing salinity, preserving fresh water, draining waterlogging and preventing floods for more than 3,000 hectares of rice in the Nam - Hung - Nghi region. Photo: Phu Huong |
Severe heat, low water levels in fields and rivers are factors leading to the risk of seawater intrusion, affecting agricultural production. However, there are still many difficulties in preventing and combating saltwater intrusion. With the task of preventing saltwater intrusion, keeping fresh water and serving irrigation for the Southern Nghe An region with 23,000 hectares of rice, industrial zones and people, the Bara Nghi Quang project has now seriously degraded.
The entire automatic door system, flat valve doors, arc doors, and automatic door locks have all been broken since 2015; the traffic bridge is degraded, the bridge beams are broken. Saltwater infiltrates through the door leaks; during the drainage season, the locking system is broken so it cannot actively drain the flood.
In fact, from 2010 until now, due to the Lam River water level being too low, there is no fresh water in the downstream area of the Cam River, so from the end of the spring crop to the beginning of the summer-autumn crop, every year there is salt intrusion, especially from the Nghi Quang sluice to Phuong Tich bridge, causing the agricultural production area at the end of the Cam River to have no water for production.
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| Checking and maintaining machines serving to prevent saltwater intrusion and retain freshwater at Nghi Quang sluice. Photo: Phu Huong |
Faced with this reality, regular salinity checks, temporary repairs to works, damming of rivers, and crop restructuring are solutions being implemented jointly by localities and irrigation units. In addition to directing the adherence to fields and water channels to ensure irrigation water supply, irrigation units focus on monitoring and updating water quality, regularly measuring and checking salinity levels at construction sites; and daily monitoring and organizing salinity checks on rivers and pumping stations at risk of salinity.
At the same time, notify the local authorities about the water quality, request inspection before, during and after pumping, absolutely do not pump when the salinity concentration is >= 1%o. Update the water level line of each tide and measure the water quality, squeeze and discharge salinity appropriately.
When the water level at Nam Dan sluice gate drops from 1.15m to 0.7m, the total area likely to be affected by drought is nearly 5,862 hectares, and in the final situation when the water level at Nam Dan sluice gate is < 0.7m, the water shortage is at an emergency level, the area affected by drought can reach up to 8,754 hectares.
In the 2020 Summer-Autumn crop, Nghe An has planned to irrigate nearly 114,059 hectares, including 85,092 hectares of rice and 8,542 hectares of vegetables. To minimize the adverse impacts of drought, localities need to urgently organize and seriously implement urgent solutions to prevent and combat drought, water shortage, and saltwater intrusion according to the direction of the Provincial People's Committee.
Review, evaluate, and rebalance actual water resources to arrange summer-autumn crops in accordance with specific local conditions, on that basis, direct the conversion of crop structure appropriately, areas that do not have enough water for irrigation throughout the season must be converted to other crops, in order to ensure the entire area and food output are planted as planned. Direct strict management of water resources, prevent water leakage and loss, and distribute water reasonably and economically./.
