1. As small towns grow into larger cities, their size continues to expand. Due to the increase in urban population, agricultural land around the original urban areas will inevitably be occupied to form functional urban areas such as residential areas, etc.
2. In the process of transforming small towns into large cities, in order to alleviate the traffic pressure caused by the increase in urban population, urban roads will increase and widen. In order to save the city's precious land resources, urban roads can be developed in a three-dimensional direction, such as elevated roads and subways.
In the first round of regular inspections of hydropower dams beginning in 1995, the Dam Safety Monitoring Center of the National Electricity Regulatory Commission (hereinaftercalled the Dam Center) classified the Manman Dam as a normal dam. During the second regular inspection at the end of 2005, the preliminary opinion of the expert group was that the dam could still be classified as a normal dam. In the document submitted to the National Electricity Regulatory Commission in March 2006, the Northeast Power Grid also indicated its self-assessed safety level as that of a normal dam.
However, the expert group believes that some problems discovered during the first regular inspection have not been significantly improved, including serious problems with leaks and cracks due to frost heaving in the section of the overflow dam. In order to encourage owners to make rectifications, the National Electricity Regulatory Commission published a document at the end of 2007 classifying the Manman dam as a sick dam. This means that it can work with the disease duringant the next three years, but it must be repaired and strengthened to eliminate the “disease”.
During the second regular inspection, the dam center will locate Fengman Dam as a diseased dam or a conditionally normal dam. The main condition is to remedy leaks in the overflow dam section. In order to solve this problem, the Northeast Power Grid commissioned China Hydropower Consulting Group Northeast Survey, Design and Research Co., Ltd. (hereinafter referred to as Northeast Survey Institute) the design of a project to reduce seepage pressure in the overflow dam section. with an investment of around 52 million yuan, the construction has been completed.
At the end of May 2011, Manman Dam ushered in the third periodic safety inspection (hereinafter referred to as the regular inspection) of a group of experts. The conclusion of the regular inspection will have a great influence on the fate of the barraage.