하천과 연안 지형측량 DB구축 및 활용

Abstract

Decades later, many countries in the world will be expected to be ones with water shortages. These days, the need of water resources management is getting much higher every day and stream, coast, dam, river, and reservoir are to be one of the main infrastructures for water resource management. For example, river has positive roles for damage prevention and nature protection, so it is very important to figure out the current state of water resources. Especially, surveying techniques which furnish the basic data of current state of water resources are significantly important. The objectives of the study is to investigate and analyze the latest techniques of river topography data sounding operation technique for the construction of stream and coastal topographical data which is a base of hydrological investigation, and set the direction available to apply the sounding operational techniques for the practical usages. Accordingly, the methodology and range of this research can be summarized as below. a) The accuracy and economic efficiency is analyzed after conducting investigations such as the current state of sounding techniques and domestic examples which utilized those techniques. b) The desirable optimum operational technique is proposed for water resources such as stream, coast, river, dam and reservoir. c) The direction of database construction of topographical data is suggested for the improvement of efficiency and security.

This research drew some results from the investigation of the state-of-practices and the principles of surveying techniques and made some conclusions as follows. a) Single Beam Eco Sounder (SBES) which has been generally used is efficient from the equipment’s economic feasibility and operational availability perspectives especially for the cases of stream and coast, the availability of running ship and the necessity of lateral-profile. b) The use of Multi Beam Eco Sounder (MBES), a precise terrain observation equipment that has higher point density than plane unit, is a reasonable technique for the precise grasp of topographical state of deep level water resources such as reservoir, and etc. c) The use of total station is an efficient way, if water level is partially low. Total station can also be used for general purposes in precise terrain observations in small areas, such as lateral-profile outcome on each certain section, installation of water intake station, and aggregate extraction. d) A connecting process between water flow rate and topography survey is required to observe the rate of flow. Acoustic Doppler Current Profiler (ADCP) is a representative survey technique to observe those two at the same time. When the equipment is operated properly after considering the work field conditions and the state of flow, ADCP will be a very efficient survey method as the river topography survey for the river flow rate measurement. e) Land topography data are dependent on a digital topographic map or a leveling outcome, but there is a limit. The water level survey could furnish only rough topographic cross-section but could not reflect the frequently changeable river topography after flood. Therefore, it is reasonable to make a connection to the water level topography by making an aerial laser scanning survey (LiDAR) for topography data construction on surrounding area. f) Scanning Hydrographic Operational Airborne Lidar Survey (SHOALS) makes it possible to have coherence in the data by obtaining topography data of land and river in large area at once. SHOALS is more economical and efficient than MBES. Also, SHOALS is to make it possible to obtain uniform topography data even in the large area where it has big topographic undulating of water level. Therefore, in an area whose river topography has big undulating like lakes and marshes or where has a low water level, a water flow rate and a high transparency of water.