Evolution Of Qingshuigou Channel Lobe In Yellow River Delta

In this paper, many years of remote sensing, bathymetric data and other information, through the analysis of water flow path,channel lobe on land and evolution of underwater delta comprehensive study of the Yellow River water and then ditch the evolution of lobe, which lobe of the delta and improve the evolution of awareness and communication flow path for the water control the direction of the next step, Shengli Oilfield, and the further development of the Yellow River Delta to provide the necessary information.Since 1855 has carried out 10 times Yellow Tail diversion, water diversion ditch in 1976 and 1996, the Qing 8 Branch, the formation of the present water channel flow path. Through remote sensing image MSS754, TM432 false color composite images, visual interpretation extraction 21 years (22 periods) in the main river channel of water, high tide line and low line.According to river type, length and human control of river water and sediment under the circumstances, may be the main channel water flow path groove on the evolution of 1976-2009 period by 6: 1976-1981 estuary filling stage; 1981-1985, natural state owned shares of a single stage; 1985-1991, the artificial state of the single straight stage; 1991-1996 is not a branch of the Qing 8 before human intervention under the swing phase of the branch; 1996-2004, manual control under a single straight stage; 2004-2009, under the control of a branch of artificial swing phase.Delta land and underwater as the dividing line for the low-water line, so the use of low-water line as shoreline Qingshuigou lobe to the statistical analysis can be obtained: water ditch lobe for the gradual growth of the general trend of shoreline, including from the In the period 1976-1992 is the extension of fast, small downward trend in 1993, and began to climb, then within a very small wavy. After several cycles of shoreline from the lobes can be seen, the general length of the branch current shoreline siltation due to rapid increase in mouth, mouth and the next year due to instability, inadequate supply of water and sediment caused by erosion of shoreline length decreased.Qingshuigou lobe of the evolution of land-based Delta, made by calculating the erosion of land and the net area to be created land area and net land reclamation rate, making every million tons of sediment and comprehensive analysis of land area, etc., can be divided into four stages :1976-1992 years; 1992-1996; 1996-2004; 2004-2009. Each stage of opening up roughly the asymmetric parabola, each stage is a braided river swing due to start, the average annual sediment created land area and the highest rate of land made after the direction of extension of time in the channel stability, sediment supply port Local adequate door, while other parts of the land due to lack of delta sediment supply caused by erosion and therefore sediment created land area and land reclamation rate decreased, and then branch out swinging when the river again, the two once again increased.Collection of the Yellow River water depth measured from the 1976-2005 data year, data on the depth of Kriging interpolation surfer, and then draw the calendar year under the high-low lines, combined with the known high and low tide Laizhou Bay Yellow zero and the ratio between the Yellow Sea each year zero-drawn noodle. Then the study area data for each year of zero water depth above the depth of all the data noodle zero.Depth information through the use of many years, the use of indoor water channel processing software on the Yellow River subaqueous delta lobes calculated scour (sediment dry bulk density approximation to take 1.1t/m3), the study area in different time underwater Triangle 1976-2005 analysis of the evolution of continents, mapping the study area was divided into the underwater delta evolution stages: 1976-1980 multi-center phase deposition; 1980-1991 single stable phase deposition;1991-1996,slow sedimentation period; since 1996, deposition, erosion synchronization phase, there is a subaqueous delta deposits in the body of the accumulation of new centers and the old mouth of the estuary erosion center.Flow of water through the ditch, ditch water delta lobe land coastline, in the erosion area and the evolution of underwater delta analysis, together Qingshuigou lobe can be divided into four stages:â‘ 1976 ~ 1980 years the first stage. Yellow River water diversion ditch early, water scattered, multi-strand into the sea, no steady flow path, when the formation of long and narrow shape of underwater delta, and a number of deposition centers;â‘¡1980 ~ 1991year second phase. Stable distributary channel, forming a single into the sea road, river extension, more stable water channel flow path forward, the trend of the coast and the Coriolis force, the main channel continued to shift to southeast. The subaqueous delta formed during the accumulation of sand irregular oval shape, long axis parallel to the shoreline;â‘¢1991 ~ 1996, the Qing 8 is not a branch before the third stage, late into the lobe development, land reclamation rate slow down, form more stable.â‘£1996 after Qing 8 Branch , since the sand spit extending back down river several times a swing, a new underwater delta estuary Accumulation and erosion of the old mouth of the water body showed oval.The important factors of lobe evolution are: the amount of estuarine water and sediment, human intervention and control, flow, wave and so on. And the amount of water and sediment carried out regression analysis.