Research On Soil And Water Conservation Monitoring On Traffic Contribution Project In Sichuan Province

Soil and Water Conservation Monitoring is one measure that can protect the soil and water resources, improve and protect good ecological environment. And it can provide scientific basis for planning, design, implementation and evaluation of soil erosion control measures through various methods such as investigation and measurement and so on.Soil and water Conservation Monitoring is the basis of macro decision-making that a country starts ecological construction, which is the important part of soil and water Conservation. It is also the basis that we do acceptance of soil and water Conservation Project. And it can promote soil and water conservation information and modernization. It is an important mean that can help us preventing and controlling soil erosion, making evaluation of control and administrative enforcement.Traffic Construction Projects makes the soil erosion problem seriously because it takes long time to be finished, and it will produce much spoil because of its large scale. The ecological environmental problems are particularly serious in Sichuan Province, whose ecological environment is being broken down because of traffic contribution project development. So that we take soil and Water Conservation Monitoring in Sichuan for example will have important significance.This study takes Ya'Shi highway project in Sichuan province for an example. It summarizes characteristics of the soil erosion on highway project, analysis and summarizes methods of the soil and water Conservation Monitoring. In this study we establish a reasonable index-system of Soil and Water Conservation Monitoring, and discuss some problems in our monitoring work. The main conclusions are followings:(1)The total characteristics of Traffic construction project soil erosion are followings:the water erosion occurs primarily with the occurance of mass erosion at the same time, mixed erosion such as mud-rock flow is also very common:it mainly occurs in the construction period; the each prevention district is different from the using way and the original landform type and the soil erosion characteristic is also different; the soil erosion can be reduced if we take soil and water conservation measures in accordance with the Soil and Water Conservation program.(2) We combine the ground method and investigative method to soil and water conservation monitoring of transportation construction project. Ground monitoring methods contain simple observation field soil erosion (Pile nailing), simple slope measurement method, residential runoff method, these methods can meet the needs of soli and water conservation monitoring of traffic construction project. (3) The principles of layout of monitoring sites are effective and complete to monitor soil and water loss, and the effect of various control measures. Mainly to typical soil conservation monitoring, and combine with main and the general method.We laid 23 monitoring points totally in this study, and 3 posts with monitoring of plots on disposal areas,6 plots herb survey,2tree survey plots,3 slope surface runoff plots and 3 simple slope measurement samples, total 17 monitoring fixed-point in Ya'an, YingJing damp and rainy area; And there are 3 simple slope surface soil erosion observation fields on abandon slag fields in each areas, south of Da xiangling with middle rainfall and dry and rainless valley of Dadu river.(4) In the year of 2010, the annual rainfall of Ya'an, YingJing damp and rainy area is 19690.0mm, and the most rainfall is 352.8mm in August, the amount rainfall in rainy season had the 57.3 ration of annual rainfall. The annual rainfall of south of Da xiangling middle rainy area is 962.1mm, and the most rainfall is 264.3mm in June, the amount rainfall in rainy season had the 77.2 ration of annual rainfall. The annual rainfall of south of dry and rainless valley of Dadu river area is 858.4mm, and had the most rainfall in June, the amount rainfall in rainy season had the 76.2 ration of annual rainfall.The rainfall distribution is uneven in the year, we ought to avoid the rainy season to implement strong and large excavation in construction process, layonting the protection measures and enhancing the temporary cut drainage, coverage and other protective measures in rainy season. The area that disturbed and damaged in construction process of Ya'Shi highway is 713.9hm2, and 697.4 million m3 abandon slag, too.(5) The runoff and rate of sediment are increased with the increases of rainfall intensities under different plant measures. The differences are significant under different rainfall intensities in the same plant measure. The greater the rainfall intensity, the more the amount of slope runoff; The difference of sediment in runoff is significant in sediment in runoff is significant clover growing areas, the bigger the rain intensities, the larger the sediments in runoff;Clover growing areas of sediment runoff rates were significantly different, rainfall intensity the greater the higher the rate of runoff sediment; Ryegrass planting vegetation cover was low, prone to soil erosion under rainfall, so the runoff overlying sediment surface area ratio and the new rate of runoff sediment was not significant. Ryegrass growing areas with low vegetation cover, and going with soil erosion easily under rainfall, so the difference is not very significant between Ryegrass growing area and new surface soil.(6) The difference between different engineering measures and amount of soil erosion is not significant under certain rainfall condition and the similar slope conditions. Compared with the usual condition, which is the more engineering measures on side slope, the lower the soil erosion, the result is abnormal. It may be caused by the following reasons:The surround of side slope, without engineering measures, is riche in nature ditches, which can guide the water out of the slope quickly. The soil erosion reduced, because of the reduction of runoff. It led the difference is not significant between slopes with engineering measures and without engineering measures; The catchment area of slope, without engineering measures, is smaller than the two others', which can led the difference significant between the slopes become small too.(7) Via the study of soil erosion characters monitored by simple observation field along the Ya'Shi highway, we know that there are significant differences between different slopes and soil erosion in the same climate area, the larger the slope, the more the soil erosion; There are significant differences between different climate areas and soil erosion in the same slope, too, the larger the amount of rainfall in area, the more the soil erosion.