The Quantity Of Sediment In Dam System And The Reinforcement Of Warping Dam In The Chenggouhe Watershed

As an important engineering measure in the comprehensive management of small watersheds in the Loess Plateau,the warping damis called the“last line of defense”for soil erosion because of its important role in sand silt retention and slow sediment deposition.It is also the“highlight project”that was established by the Ministry of Water Resources in 2003.After the warping dam is in operation,it's an important basic work for the management of the silting period of the silting dam and the danger and dam reinforcement,and the monitoring of the siltation quantity and source of the silo in the reservoir area and the dangerous dam.The dam system safety management and operation has a vital role.In this study,the Yellow River Basin pilot dam system and the key monitoring dam system called the Chenggou watershed were selected.Based on mathematical statistics,remote sensing information technology,and soil and water conservation dynamic monitoring technology,three types of storage capacity curves that were using field measurement,3S technology generation,and original design were compared and analyzed.Investigation on the source of sand interception in the dam system of the Chenggou watershed and investigation on the danger removal and reinforcement of the dangerous deposit check dam.Main conclusions achieved are presented as follows:(1)Analysis of three storage curve.The same silt height,the measured reservoir capacity curve value in the checkpoint dam>the reservoir capacity curve value extracted from the topographic map>the original design capacity curve value,the difference increases with increasing altitude;at the end of 2015,the measured values of the key dam and the topographic map extraction values are 90.31%and 110.06%of the original design value;the measured value of the medium-sized dam and the topographic map extraction value are 135.92%and 110.05%of the original design value;the measured value of the small dam and the topographic map extraction value are 118.33%and129.76%.of the original design value respectively.(2)Analysis of different types of sediment deposition.By the end of 2015,the average silt content of each dam in key dams,medium-sized dams and small dams was 49591 m~3,4187 m~3 and 1715 m~3.The mean value of sedimentation morphological discriminant coefficient was 48.238,which was delta deposition,and some small dams were vertebral deposits.The erosion control modulus of the dam control area ranged from 225 to 2719 t/(km~2·a)with an average of 1382 t/(km~2·a).(3)Analysis of sediment source.Of the 50 silt dams,30%of the silt dam area was gravitationally eroded,and the key dam reached 53%.26.1%of the total dam deposits originate from gravitational erosion;a gravitational erosion forecasting method is given and preliminary validation in this study.(4)The cause of dangerous conditions and the reinforcement of dangers.15%of the warping dams in the whole basin have a dangerous condition.The types of major types of hazards are mainly dam body dangers,draught building accidents and spillway hazards.The main cause of disease risk is due to the seepage of dam body leading to cracks,landslides,cracks and depressions caused by the settlement of culverts and lying pipes.The original design had no spillway or spillway sections with small size,etc;and put forward countermeasures for reinforcement.