발파 진동레벨을 이용한 내륙 양식장의 수중소음 추정과 양식어류류 피해기준 제안

Abstract

With the rapid growth of the industrial economy and a growth-oriented economic policy, demands for development of national territory have been increasing annually. In particular, as diverse construction projects such as road construction, tunnel excavation, subway construction in metropolitan cities, and reconstruction of old buildings have been very active, we have suffered from environmental problems such as noise, vibration, fly rock and dust. In fact, of 3045 cases of grievance mediation which were dealt with between 1991 and 2013 by the National Environmental Dispute Medication Commission, about 2600 cases(about 85%) were related with noise and vibration(National Environmental Dispute Medication Commission, 2013). Some dynamic investigations on damage compensation for land based animals have been made, management standards have been enacted, and supplementary measures suitable for real conditions of construction areas have been developed and compensation was given in cases when the damage exceeded the management standards. However, as for noise and vibration occurring due to construction near fish farms, engineering and the technical opinions of experts in different areas were excluded in calculating any damage . The victims tend to present only biological consulting-based opinions while construction companies tend to present information on general construction noise and vibration as they have little biological knowledge on fish. Thus, in most cases, it is difficult even to find common measurements between those concerned as there are few objective and well balanced engineering and technical approaches. So, the National Environmental Dispute Medication Commission presented specific damage standards and compensation calculation standards in 2009 through studies on damage assessments to pond grown fish on farms that was caused by noise and vibration. As farming techniques have developed, the kinds of farmed fish have diversified and the farm sizes and number have increased. Therefore, when civil engineering construction is done near fish farms, there are civil appeals against the noise and vibration coming from the construction projects, and an immediate response to the appeal is difficult because of the poor objective data and this problem will increase the construction period, resulting in the increase of the construction expenses. With regards to the impact on fish in farms, underwater noise is the main source of damage. Existing noise and vibration measurement equipment used are a speed meter for structures and an acceleration-based level meter for human bodies. A speed meter has been frequently used as its use was recognized as natural in blasting and both domestic and foreign-made equipment is used equally. The acceleration-based level meter has been frequently used for environmental studies. However, underwater noise measurement equipment is not normal as it is expensive and its export procedure is complicated. A few articles published recently show that there are methods to predict underwater noise through correlations based on measurement data of blast vibrations and underwater noise collected using a speed meter from test blasting. However, it was reported that there were empirical cases when underwater noise was predicted with the use of an acceleration-based level meter, but there were no relations to estimate blast vibration levels obtained through actual measurements related to underwater noise. To examine existing damage impact assessments by national researchers, there were damage standards citing American and Canadian data and impact assessment methods using Japanese data. It was judged that the impact assessment methods using Japanese data are usually conservative because the Japanese data used R.M.S data of continuous sounds and the American and Canadian data differentiated continuous sounds from the impulsive sounds. So, this study presented a relation to predict the vibration level with underwater sound pressure level to predict underwater sound pressure without measuring underwater noise and examined the problem in that minimum measurment level are different according to the manufacturers in measuring the background vibration with vibration level measurement equipment in the field. This study analysed the problem in existing damage assessment standards for land farmed fish through visual observation in measuring underwater noise in the field. So, the background of this study was to differentiate whether Japanese data based on national farm fish damage assessment standards used impulsive sounds or continuous sounds, and to check whether the fish died through visual observation. This study aimed to develop a base for having fewer disputes by correlating blast vibration level with underwater noise using a vibration level meter when there is a blast near fish farms and there is no underwater sound measurement equipment, or measurements can not be made at farms because of other reasons. Also, our country accepts 140 dB re 1 μPa as a damage standard of underwater noise. This standard is the R.M.S value of continuous sounds for more than one second, not the impulsive sounds. To look up data on existing studies, fish showed different reactions to underwater sounds according to the different kinds of fish such as ostariophysan or non-ostariophysan, and pinnipeds or non-pinnipeds. So, this study will present damage standards for impulsive sounds in consideration of the differences in the characteristics of the impulsive and continuous sounds.