Concept of rainwater harvesting area of reservoir

1, the concept of rainwater collection area: the surface size of rainwater per unit length and width is called rainwater collection area. It is also called water area, such as a courtyard surrounded by dikes. The area within the dike line is a rainwater collection area. If there is no flood drainage ditch in the courtyard near the hilly area, in addition to calculating the plain area within the dike, the water area in the hilly area should be added. When the courtyard of the flood drainage ditch is excavated, the inflow area in the hilly area outside the flood drainage ditch is not calculated, and the rainwater collection area is in square kilometers.

The rainwater collection area of a river is not only its basin area, but also the rainwater collection area of a reservoir is the sum of the rainwater collection areas of all rivers that converge to this reservoir. A sub-basin refers to a tributary basin of a river or water system.

2. Rainwater collection area of the reservoir: it is the inflow area of the reservoir, and any area where water can flow into the reservoir is a range on the plane.

3. Sketch of rainwater collection area

Determining the catchment on the topographic map usually has the following characteristics:

The (1) boundary starts from a designated point on the river and finally returns to the origin, forming a closed loop.

(2) The boundary line passes through each saddle that separates different watersheds.

(3) The boundary line should be perpendicular to the contour line everywhere.

(4) The boundary line often coincides with the ridge line.

(5) The boundary line can suddenly change direction only at the top of the mountain.