As an important artificial lake in Fuzhou, Qinting Lake has become increasingly serious since it was basically completed in 2009. Especially after the typhoon Sudiro last year, the silt at the bottom of Qinting Lake, which originally designed a total storage capacity of 710,000 cubic meters, increased significantly, seriously affecting capacity of flood storage. The reporter learned from the urban construction department of Fuzhou yesterday that Qinting Lake recently launched the “desilting back to the Lake” for the first time. It is expected that desilting will exceed 80,000 cubic meters and strive to be completed within the year.
In the reach east of the Dragon Head Road, the water level drops, revealing a large amount of silt.
Large excavator has entered the site to remove silt
There are many sediment collected in the upstream, and the lake bottom is seriously silted.
Qinting Lake is a comprehensive utilization project of water body mainly based on water conservancy and flood detention, supplemented by urban landscape. It plays an important role in flood control and drainage of surrounding areas, covering a total area of 31.6 hectares and a total Lake storage capacity of 710,000 cubic meters, the flood volume is 576,000 cubic meters.
“After it was basically completed in 2009, it has not been desilted.” The relevant person in charge of the general manager of urban and rural construction in Fuzhou said that there were many rivers in the upper reaches of Qinting Lake, many of which originated from the mountain and the water contained a lot of sediment. Nowadays, the situation of siltation at the bottom of the lake has been very serious, especially after Typhoon Sudiro last year, capacity of flood storage has been greatly affected, and dredging has become imminent.
It will be completed by the end of next month in three areas.
The reporter learned that the scope of this lake dredging includes Qinting Lake and some upstream rivers, and the dredging construction will be carried out in three areas. Among them, Area 1 is the river from the government of Xindian town to the leading road, Area 2 is Qinting Lake west of qinting viaduct, and area 3 is Qinting Lake east of qinting viaduct.
At present, Area 1 has entered the site for construction and the construction of access roads is under way. Yesterday, the Haidu reporter saw at the scene that the water level in this area had dropped very low, revealing a thick layer of silt.
According to previous calculations, the depth of Qinting Lake silt ranges from tens of centimeters to about two meters, and the total silt clearance will exceed 80,000 cubic meters. The person in charge of site construction said that in order not to affect flood discharge in flood season, Areas 1 and 2 will strive to complete dredging before the end of June. Due to the deep water in Area 3, the construction is more difficult and will strive to be completed within the year.
Qinting Lake is far more difficult to clear silt than left Sea
In recent years, Zuo Hai of Fuzhou has also carried out dredging. The reporter learned that the difficulty of dredging Qinting Lake is far more than that of Zuo Hai.
“Zuohai desilting can be completely closed. After the water is completely drained, it can be excavated and cleaned. While clearing siltation, Qinting Lake must ensure the mobility of the water body to ensure that normal flood discharge will not be affected when it rains.” The relevant person in charge of the general manager of urban and rural construction in Fuzhou said, therefore, the construction of the cofferdam should not be too large, and special diversion ditches need to be excavated on the bank of the river. In sunny days, the flow can go through the diversion ditch. Once it encounters heavy rain, they withdraw all the equipment to free up the river to meet the needs of flood discharge.
In addition, the revetment needs to be reinforced and protected during the dredging process to prevent the stability of the revetment from being affected after construction. At present, the reinforcement construction of diversion ditch and revetment is in progress, making preparations for the formal dredging.
Water quality of Qinting Lake and Jin’an River or affected
What impact will this dredging construction have on the surrounding areas? According to the person in charge of the on-site construction, since desilting is carried out within the water body, it will not have any impact on the surrounding traffic. However, because large machinery needs to be constructed in water, it is inevitable to stir the silt at the bottom of the lake, and the water body of Qinting Lake may be turbid.
In addition, the water quality of the downstream Jin’an River may also be affected. In this regard, the relevant person in charge of Fuzhou Urban and Rural Construction said: “The impact is only temporary. After the dredging is completed, the water quality of Qinting Lake will be improved. The problem of the smell of silt in summer reflected by the surrounding residents will also be greatly alleviated.” (Reporter Wang Lincheng/Wen Baohua/picture)