What Is a Sump Drain?

Drainage ditch refers to the drainage ditch that draws the water collected near the side ditch, cutoff ditch and subgrade, in crop fields, and low-lying areas near houses to the subgrades, crop fields, and residential sites. Design of drainage ditch According to the drainage system engineering layout and engineering standards, determine the depth and spacing of field drainage ditch, and analyze and calculate the flow, water level, section size and engineering volume of drainage channels and buildings at all levels.

1 Drainage ditches are generally arranged at the two ends or lower ends of the intercepting ditch on the slope surface to exclude surface runoff that the intercepting ditch cannot accommodate. The end of the gutter is connected to a cistern or natural drainage channel ^[1]

(1) Section A _{2 of the} drainage ditch. Calculate the maximum runoff on the sloping surface according to the design frequency according to the open channel uniform flow formula ^[1]

Design of drainage ditch According to the drainage system engineering layout and engineering standards, determine the depth and spacing of field drainage ditch, and analyze and calculate the flow, water level, section size and engineering volume of drainage channels and buildings at all levels.

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Generally, the depth of the drainage ditch is initially determined according to the buried depth H of the groundwater required by the crop and the construction conditions, and then the corresponding drainage ditch distance is determined. Due to the complex hydrogeological conditions in the drainage area, the depth and spacing of drainage ditches need to be selected through experimental data and successful experience analysis in similar areas. Drainage design flow Design flow is divided into two types: drainage flow and rehearsal flow.

When calculating the design flow, first determine the design drainage modulus for these two cases (see Drainage Modulus and Rehearsal Flow t), and then multiply by the corresponding confluence area corresponding to the drainage ditch section, that is, the drainage design flow and the drainage design flow . Drainage ditch water level and cross-section drainage ditch shall have sufficient water carrying capacity and appropriate design water level.

The design water level of the drainage ditch is divided into two types: the drainage level and the drainage level. The rehearsal level is the level that the drainage ditch should normally maintain, and it mainly meets the requirements for controlling groundwater. In order to ensure that the water level of the agricultural ditch is not high, the drainage water level of the bucket, branch and dry ditch must be gradually lowered. In addition to the vertical slope of the water flow, there must be a proper water level drop at the confluence of the channel at all levels, generally 0.1 One 0.2 meters. The drainage water level is also called the highest water level, which is the water level when the drainage ditch passes the drainage design flow. At the time of drainage, the water level of the trenches at all levels should not be higher than the elevations of the fields on both sides of the trenches, and preferably 0.2 to 0.3 meters below the fields. In the case of pumping and waterlogging, the drainage ditch section receiving the drainage pump or the drainage ditch section through a small depression allows the levee to be built so that the water level in the ditch is higher than the elevation of the fields on both sides. The section size of the drainage ditch is determined by hydraulic calculation. First select the vertical slope at the bottom of the drainage ditch, the slope coefficient of the cross section and the roughness of the ditch bed. Drainage ditch slopes tend to collapse due to groundwater escaping, so slower slopes are often used. Because the drainage duration is short, the ditch slope is easy to grow grass, and the roughness of the ditch bed is large, so the impact resistance is strong, and a steep vertical slope can be selected.