About 1 million years ago to 0.7 billion years starting in the late Cretaceous Yanshan movement, began to constitute a lake landscape background, with the Xuefeng Mountain uplift, the basin north of the ordinary peach to accelerate settlement, the rapid eastward expansion of the scope of depression , Romania and the eastern basin of tears connected forming a west Shihmen, Guanxian, east Yueyang, Xiangyin north, Ann Township, Tainan County, south of Yiyang, Ningxiang inland lake Dongting. Mufu peripheral uplift Lake, Wuling and Xuefeng uplift uplift uplift difference occurred, with the Dongting basin formation marked depression topographic contrast. Peripheral bulge formed by these mountains, in an intense erosion, erosion of a large amount of debris, the accumulation of short-distance transport to the basin of accumulation. Therefore, the Dongting basin sediments to coarse clastic piedmont alluvial accumulation phase features. With the accumulation of sediment filling, the lake is shrinking, the lake basin around and raised the sub-terrain and gradually leveled by erosion, strong evaporation basin runoff to import become very weak . To the late Tertiary, the basin has been completely dried up, this is the first time the Dongting Lake was reduced.
into the Quaternary crustal movements and activities together, inherited the early Tertiary period of features of the Himalayan movement, the difference between sinking down and block off the main access to the lake as Na Xiang, Zi, Yuan , Li River, the North injection of fresh water lakes of the Yangtze, also received a total area of more than 1200km2, more than 300m thick lacustrine, fluvial, lacustrine sediment, forming a lake as the center of convergence to the heart of the Water and broad low-lying plains of the Lake. Up to 200 years in the Quaternary, although the magnitude and strength of the subsidence occurred over many times, the lake many times to expand, reduce, or even leveling of warping, but the general trend of crustal movement Lakes continued settlement .
the early Pleistocene, the lake basin due to fault activity again, differentiation of a series of bumps and depressions, especially in the central lake Chishan longitudinal raised connected with the Huarong uplift north and south, separated by the lake to the East and western parts, respectively, Yin Shen Jiang Yixiang Muping Depression Depression and the two pieces as the main lake.
the early Middle Pleistocene, Lakes, where a strong difference in movement at the lake periphery strongly increased, the lake continues to settlement, topography contrast increases. As early as the late Pleistocene settlement in eastern xiangyin pouch further expansion of the north this Yueyang Kwong Hing Chau and the Early Pleistocene lake through convergence, it is in the early Pleistocene, mid-range expansion of water for the lake since the Quaternary development zenith.
early Late Pleistocene, with the worldwide emergence of low sea level, under the Yangtze River bed, where a strong cut, the old riverbed of the Yangtze river has been lifted for the distribution of Yuhuatai gravel platform. As the water level of Dongting Lake exports decline, leading to the lake rapidly drained and the rapid decline of the lake, the lake into the bottom of most of the exposed land, the formation of a lakeside terrace surrounded by the river plain. Late late stage due to the edge of the lake, the hills further elevation, especially in the central basin and the northern part of Huarong Chishan uplift raised further uplift, surrounded on both sides of the Muping Chishan South Lake two sag basin become the confluence of the rivers into the lake area, and in some settlement centers, such as Xiangyin west, Shen Jiang Huangmao Zhou, tea tray Chau, North City and Ann Township, Tainan County northwest to form a small number of shallow lakes. East and West Dongting Lake area south to north flow of water each, the East branch by Chun-shan. Mausoleum City alum empties into the Yangtze, to the north west branch first stone by An Xiangdong Mission Hill, Ouchi from this flow into the Yangtze River mouth area of the north. West branch may also be through Fairy Lake County Third, the fish population in the area and the East branch connected. Last couple of years since the Holocene period, the lake still has a sinking trend. Modern repeated leveling data show that the lake has still an annual rate of 6.4-11.4mm sink.
from the lake evolution, under natural conditions, the lake has been repeatedly expand and contract, and even the basic die off, mainly due to geological subsidence, the Yangtze River floods, sediment deposition and the evolution of the Yangtze River, etc. , compared with the age of the Yangtze River, Dongting Lake and the much shorter life cycle.
since the dawn of humanity, human factors impact on the lake sedimentary environment caused by tectonic subsidence gradually over the natural factors that make the Jingjiang River and Dongting Lake water level relations have undergone many changes in contrast. Jingjiang flood diversion into the lake during the deposition of sediment into the volume, have been far better than the Xiang, Zi, Yuan, Li-based Dongting Lake water system water into the sediment deposition itself. And human cultivation in the Lake District around the lake, and the corresponding different time constraints and limited natural lake and the deposition zone distribution area. Early Holocene, mid-lake sediments,Discount UGG boots, expressed as the natural factors still play a major role in the feature. The late Holocene, especially during the almost 2,500 years, human factors are increasing.
archaeological data to show that, at the latest dating back 10 million years ago, human activities in Hunan Province have so far found in the Neolithic lake has reached 40 multiple sites, reflecting the middle of the Holocene , human activities have generally entered the Lake District. In about 9000 years ago to 7,000 years, hunting and fishing and gathering economy, though still occupies an important position, but to cultivate the raw rice-based agriculture and cattle, pigs and other animal husbandry industry has generated.
Qin and Han Dynasties, the lake also known as Area of the lake was more than 6000km2. Qin Shi Huang Tongyiliuguo, Wuling obstacles to overcome to ensure the smooth transport rations, orders and transportation in-depth history of the more Drainage Paul chisel, the use of Hunan, Guangxi, an ancient carved valley canal Lingqu, communication dihydrate Xiang Li River, connecting the Yangtze River Pearl River System. Eastern Han Dynasty, Northern frequent wars and turbulence, Dongting Lake and Xiangjiang River population growth, the development of the natural vegetation reclamation has been a certain degree of damage. West Lake due to the long slow deposition, coupled with artificial lake reclamation to reduce the lake level Yong reason why they are high above the Jingjiang, resulting in the original lake water flows northwest and south of the tiger to cross the river Dengjun Jingjiang flood diversion gradual blockage. Three Kingdoms period of Water from
Southern and Northern Dynasties, the Dongting Lake area reclamation activities have begun to take shape. Hunan Dongting has All the other edge of the lakes near the surface 6000 km2.
Jingjiang dike began in the Eastern Jin Yong years, so Mr Chan Huan Wen was the provincial governor in the Jingjiang River above the Jingjiang River north of Gangneung build Gimje, tired after a plus repair. Five, the high season Hing separatist Jingnan will Jing Jiangnan, northern embankment is integrated and north to the drag from Mao Dangyang port,UGG shoes, south to the city from the hills Songzi alum, the length of six or seven hundred years, but the south bank of the dike is more thin . The south bank of the Jingjiang levee breach often burst, so that they accept the Jingjiang flood of Dongting Lake sub-water sand, the lake into the river over the last few minutes the river, then also the river into the lake leaked into a watercourse. Originally leaked water into the Yangtze River in the Ouchi River Northern Song Dynasty was from embankment separating the two: Songzi County upstream into the river directly downstream of the oil belongs to the tiger to cross the river mouth of Dongting Lake has become a diversion Xuekou Jing Jiangnan one pass.
from Sui to the Tang, the Jingjiang River and Dongting Lake kept the Northern and Southern Dynasties, End of Tang Dynasty, the gradual improvement in Jingjiang dike, and also will raise the flood level, so that Wei has been the Tang and Song Dynasties, the country's economic center of gravity shift from the Yellow River to the Yangtze River. After the Tang dynasty, Hunan pay forest vegetation cutting firewood mining, slash and burn while the situation has become serious damage, the slow deposition of sediment in lakes, the lake gradually silting shallow lake of Reclamation has entered a new peak period. Northern Song Dynasty, the North turmoil, the Central Plains population across the border again, the lake area reclamation activities in the private sector development, the government also conducted a large-scale reclaim the land, so that the lake water area is further reduced. Reduce the expansion of Dongting Lake and the Bamboo Tang, two lake is almost equal. Sum of two lakes, with a total area of only 2350km2, with red edges of Sand Lake and other lake, the Dongting Lake area was an area of 3300 km2 of natural lakes around the lake area when compared to Mitigation of reducing by nearly half.
to the Song Dynasty, especially the Southern Song Dynasty, the rapid development of the lake reclamation greatly reduced narrow lake, Dongting Lake area of natural lakes smaller than the Tang Dynasty. Song of Dongting Lake water due to the impact of Jingjiang flood diversion, lake water regime and sedimentation occurred in three significant changes. First, the water level of the East Dongting Lake flood Jingjiang Hong effects of backwater from the water level gradually evolved to flow backward into the lake. Five Sun Guangxian first mentioned by the Yangtze River and Dongting Lake and Xiangjiang River flood runoff leaving the lake to expand each backwater: runoff begins each backwater Five Dynasties and Song appear three to five days on the river flow backward into the lake, the Southern Song Dynasty in June and July has reached ten years of intrusion, the intrusion of September there are also three days. Second, seasonal changes of flood dry lake, and the constant increase in flood season. Third, the Jingjiang River sediment into the lake, lake sediment more rapidly, increasingly shallow water depth.
Yuan and Ming dynasties, Jing Jiangnan shore levee breach often, flood Jingjiang flood into the lake, the amount of increase, while the lake is at a low stage of reclamation, flood embankment caused by natural waste is also widespread occurrence of the lake, so lake area is expanding and increasing silt shallow lake. Yuan, Jing Jiangnan decision shore embankment tired tired building. Ming, Dongting Lake water disrepair, Jingjiang burst, lake embankment collapse situations occur. particularly Jiajing thirty years (1560) from the upper reaches of the Yangtze River floods, the Jingjiang break dozens of West Bank, including The breach is the most crucial Zhijiang Barry Island, Songzi mouth toward the British, Gangneung tiger crossing, police shops and Ai Jia Yan shaking his head, mouth, etc. Shishou Ouchi, Jingjiang Hong water which dropped from the Huangshan mountains on both sides of overland flow into Dongting Lake Deer Lake Lakes region. Jiajing forty-five years since (1566), the Jingjiang levee repair and one by one, and set Polder is only to be repaired late Wanli recovery. Longqing years has opened along the Xuekou proposed, in fact, the only tuning a dredging, flood water only by Tiger crossing Jingjiang Hong, tuning two spilled into the south to the lake. Lake flooding was aggravated widespread waste fields and lakes. caused flood water level elevation lake causes flood can be divided into two. the one hand,UGG boots cheap, Jingjiang Hong uplift water level, resulting in the backwater of the lake. On the other hand, due to lake bottom sediment into the lake caused the rapid increase in silt pad, thereby reducing the volume of the lake, the lake water level has also led to the uplift of the flood season. Yuan and Ming Dynasties natural lake Dongting Lake area, according to research, estimated at around 5600km2.
early Qing Dynasty, only the tuning of Jingjiang, tiger crossing the two flood diversion into the lake. Ouchi 1852 and 1870, Songzi breach, the formation of a four Nanliu situation, the amount of Jingjiang River diversion into the lake increased sharply on the Dongting Lake Evolution of the immediate impact is once again rejuvenate and grow. Guangxu print and publish the 5400km2.
the four sub-entrainment into the lake, a large number of flood sediment into the lake, the lake and keep silt into the shallow water channel, the lake to the continuous deposition of high, they will build a new embankment and rolled. According to the Lake District 1 / 25000 topographic map and calculating, the lake area in 1949 4350km2, 1978 was accordingly of the lake area has been reduced to 2691km2,UGGs, former 八百里洞庭 Great Lakes landscape, has been lined with large dike project is divided into flat plains, South Dongting and three from the East Dongting lake associated Hung Road. At present the lake area of 2625km2, less than 40% in 1949, also by the lake volume of 29.3 billion m3 in 1949 to the current reduction of 16.7 billion m3, a decline of 43%. < br>
Lake Dongting, becomes large or small before human activity is a natural process of evolution, as the Jingjiang River flow capacity constraints, excess flood is not the north into the Yunmeng Ze is the south into the lake . But the man in the lake reclamation and the construction of the Jingjiang levee after the flood way is no solution, resulting in frequent flooding of the Yangtze River and the complex relationship between rivers and lakes. Jingjiang, Jianghan Plain and Dongting Lake is not only reflected the complex relationship between the natural context, also because of their different interests, resulting in both Hubei and Hunan flood control strategy and the different point of view, disputes and conflicts over the centuries has always existed, so the rivers and lakes of the Yangtze River and coordination between the need to study natural and human double complex.
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