四六分水 二八分洪是什么意思

Dujiang weirs constructs in 256 B.C., is the world until now, the age is most long, only preserves, take the non-dam pilot as the characteristic great hydraulic engineering.2000 for many years, it has been playing the flood prevention irrigation role continuously, causes the Chengdu plain to become the flood and drought from the human, the vast fertile area land of abundance.World culture inheritance - Dujiang weirs tourist area for national AAAA level traveling scenic area, state-level scenery scenic spot area.
The Minjiang River is upstream a Yangtze River's big branch, originates north Sichuan the mountain area.Whenever spring summer mountain flooding, river water galloping under, enters the Chengdu plain, because the river course is narrow, as soon as the ancient times cause the flood disaster frequently, the flood draw back, also is the grit great distance.East but the Guanxian Minjiang River east bank jade builds the mountain to hinder east the river water to flow, creates west the drought the waterloggingNo matter what the Suchuan county grand minister superintendent of KULUN, he benefits the people, removed trouble of the flood disaster, the management has constructed the famous Dujiang weirs hydraulic engineering.
Dujiang weirs's principal part of a project is divides into the Minjiang River current of water two, current of water introduces the Chengdu plain, like this both may reduce the flood reduces disaster, and had achieved channels water to irrigate fields, turns bad to good.Moreover converges Yangtze River.Dujiang weirs hydraulic engineering most main part for Dujiang weirs headwork, this is in the Dujiang weirs irrigation system is most essential, the most important facility.The Dujiang weirs headwork mainly by the fish mouth divergence dike, flies the weir on sand spillway and the valuable bottle mouth drainage project three major part is composed.It solved the river water automatic divergence, the automatic discharge of silt scientifically, has controlled questions and so on discharge of water, three head and tail docking, took care of mutually, the day becomes quite the same as, wonderful workmanship.

都江堰排洪的比例
是四六分洪，二八排沙

不知道