Dynamic Monitoring On Bank-collapse Hazards Along Heihe-Fuyuan Segment Of Heilongjiang River By Remote Sensing Technology

Remote sensing technology is a comprehensive technology, which is based onelectromagnetic wave theory．The electromagnetic wave radiated and reflexed by remoteobject is collected, processed and imaged by sensors for detecting and identifying groundobject．Remote sensing geology is a discipline and technology which is based on informationof electromagnetic wave acquired and collected by sensors to research the status and the lawsof geology, mineral and geological disasters．Integrating remote sensing and GIS technologycan achieve the goals of topographic mapping, geological structure analysis, preliminarysurvey to surface and shallow ore zones．With the development of artificial satellitetechnology, getting space picture is becoming more and more easily, using remote sensingtechnology to conduct the work of geology is becoming more and more low-cost and faster.In the middle and lower reaches of Heilongjiang river, because of long time water scouringand erosion, soil loss is serious, which causes economic losses of frontier resident, harmingthe bilateral political relations and long-term stable development between two countries．As aresult, it has significance to study the Heilongjiang bank-collapse hazards, survey the status ofHeilongjiang coastline changes, study the causes and factors of occurrence of bank-collapsehazards, and propose the treatment and measures of preventing such disasters．This paper uses multi-temporal remote sensing images data and topographic maps data tomaking topographic maps DRG and remote sensing orthophoto maps. On this basis, the river shoreline, embankment protection projects, collapse-geological-hazards and fractures along Heihe-Fuyuan section of Heilongjiang river have beeninterpreted． This paper classifies geological landforms, rock and soil types, valleies,embankment protection projects, and counts, juxtaposes, analyzes shoreline changes， thesituation of bank collaps of this segment of Heilongjiang riverThe erosion area of Heihe-Fuyuan section of Heilongjiang is86.583square kilometres,including erosion along the coast lines of41.474square kilometres and45.109squarekilometres along Islands; the accumulation area is115.364square kilometres, including30.637square kilometres along the coast line and84.726square kilometres along islands. Onthe whole deposition is more serious than erosion, but erosion is more serious than cholestasisalong the coast.Bank’s features of shape are the key factor of bank-collapse hazards and the coastlinechanges. The banks can be divided into multiple concave banks, convex banks and straightbanks according to the shape features. Multiple concave banks show a higher level than theconvex banks in the numbers and areas of bank-collapse hazards, the numbers and length ofcoastline changes and coastline change rates. Cholestasis generally occurs on convex banks.Straight shores are poor in the coastline changes, bank collapse and sedimentation. This isbecause the concave banks which are impacted by water from lateral and in which erosion isterrible; however in convex banks, river’s thalweg swings to the opposite direction from theshore levees which leads eroded sediment from concave bank to deposit in the convex bank;straight shores’ thalweg is flat relatively, the river flows are parallel to the river banksubstantially, which causes less erosion, silting and coastline change rate.The rock and soil types of the river bank have significant influence on the occurrence ofbank-collapse hazards and the coastline changes. Rock embankments are less eroded awaybecause of their hardness, erosion resistant ability and having a certain structure; while soilembankments which are soft, have weak erosion resistant ability are easily washed, erodedaway. In the same case of concave bank, coastline changes and collapse geological hazards insoil embankment section are more than that in rock embankment section. Erosion and collapse status of downstream are more serious than that in upstream. Thedownstream flows bring the tributary river together, the total water of rivers increases, thekinetic energy increases, so its erosion capability is strengthened and coastline changes andgeological disasters are more serious. In addition, erosion geology disasters of collapse-bankof mountain valleys are slighter than that of plain valleys. In general, mountain valley banksare made of hard rocks, their erosion resistant ability is strong. In addition, the mountainvalleys banks are generally straight embankments, it’s camber is small, so the erosion collapsegeological hazards are slight in mountain valley.Riparian vegetation has certain influnce on river bank-collapse hazards and the coastlinechanges. Research results show that: in the same case of rock and soil types and river courses,embankments with the original turf and forests have stronger erosion resistant ability andwhich with vegetation of farmland or forests excessive harvested suffers erosion terriblely.