Manual regular observation: the base flow in non flood season adopts two-stage system, that is, once at 8:00 and 20:00; in flood season, it adopts 4-stage system, that is, once at 2:00, 8:00, 14:00 and 20:00, and the flood season is from June to September. (1) Water level observation: a side wall type water gauge group is set on the left side of the upper part of the parabolic weir to observe the number and reading of the water gauge. Regular observation of base flow in flood season and non flood season. In flood season or rapid water level change period, under the premise of reading and controlling the water level at the important turning points of rise and fall, peak top, fall level and other water level fluctuation, the measurement times are roughly evenly arranged according to the water level change. There are no less than 3 times near the peak, and no less than 11 times for a single peak. The observation is conducted 30 minutes to 1.0 hours after leveling, and each peak, valley and integrity are required to be measured The water level change process. (2) Sediment Observation: the method of one point at the water edge is used to collect sediment. The principle of sediment sampling times in flood period is to control the change process of sediment concentration. When the water and sediment peaks are inconsistent or the sediment concentration changes sharply, the measurement times should be increased appropriately. All water samples were treated by displacement method.
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CSTR:11738.11.ncdc.HWXFZhan.2020.70
10.12072/ncdc.HWXFZhan.db0002.2020
