Pemaculture - Originally the term was a contraction of “Permanent Agriculture” for that is what it was, the design and implementation of permanent (sustainable) agricultural systems.
Permaculture is a philosophy of working with, rather than against nature; of protracted and thoughtful observation rather than protracted and thoughtless labor; and of looking at plants and animals in all their functions, rather than treating any area as a single product system.
Three core values of Permaculture are:
Care for the Earth. Care for People. Fair Share (or, setting limits on consumption, and returning surplus).
Swales as used in permaculture are designed by permaculturalists to slow and capture runoff by spreading it horizontally across the landscape (along an elevation contour line), facilitating runoff infiltration into the soil.
A permaculture swale builds a self-sustaining ecosystem.Swales catch water and direct it to where it's needed, which is in the soil. Instead of water running off or pooling above ground, swales direct it downward into an underground reservoir. Nature has its own built-in, self-watering system.
Unlike ditches, swales are not deep with straight sides. They have gently sloping sides and are wider than they are deep.
The swale and should be planted with both trees and groundcovers so that the soil is stabilized. The swale also must have a level spillway so that, in times when water is overabundant, it can release safely and passively in an appropriate location without damaging the berm.
Swales are never built in straight lines.
When people play with water withouth knowing or understanding the effects on the ecosystems the ecosystems breaks such as is the case in china.
Many parts of the Yangtze and its tributaries have been straightened, deepened or otherwise altered to make shipping more convenient. But this has made life harder for the organisms that live in it.
“The river’s original meandering form ensured a diversity of habitats, some of which were shallow, or deep, or in fast- or slow-flowing water,” said Wang from the Chinese Academy of Sciences. “Animals like the finless porpoise prefer to live in shallow, meandering waters, and very few can actually survive in deep, straightened channels.”
At the same time, construction along the river’s banks and of hydropower facilities has eaten into natural habitats — a shrinkage exacerbated by the evaporation of water from lakes whose connections to the river have been disrupted by construction.
Between the 1950s and the 2000s, Dongting Lake in Hunan province, one of the biggest lakes in the Yangtze basin, shrank by nearly 40%, according to figures from the Ministry of Water Resources.
The two dolphin species were once commonly sighted along the Yangtze, and fossils suggest that the baiji has existed for over 25 million years, and lived in the river for 20 million. But by the time Chinese researchers began paying closer attention to them in the 1970s, the population of baiji had shrunk to only 400 individuals from around 6,000 just two decades earlier.
The Dujiangyan (Chinese: 都江堰; pinyin: Dūjiāngyàn) is an ancient irrigation system in Dujiangyan City, Sichuan, China. Originally constructed around 256 BC by the State of Qin as an irrigation and flood control project, it is still in use today. The system's infrastructure develops on the Min River (Minjiang), the longest tributary of the Yangtze. The area is in the west part of the Chengdu Plain, between the Sichuan Basin and the Tibetan Plateau. Originally, the Min would rush down from the Min Mountains and slow down abruptly after reaching the Chengdu Plain, filling the watercourse with silt, thus making the nearby areas extremely prone to floods. King Zhao of Qin commissioned the project, and the construction of the Dujiangyan harnessed the river using a new method of channeling and dividing the water rather than simply damming it. The water management scheme is still in use today to irrigate over 5,300 km2 (2,000 sq mi) of land in the regionand has produced comprehensive benefits in flood control, irrigation, water transport and general water consumption.Begun over 2,250 years ago, it now irrigates 668,700 hectares of farmland. The Dujiangyan, the Zhengguo Canal in Shaanxi and the Lingqu Canal in Guangxi are collectively known as the "three great hydraulic engineering projects of the Qin.
Source
https://www.caixinglobal.com/2018-07-21/what-killed-the-yangtze-river-101306836.html
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