«by: MA. ALETHA A. NOGRA Civil Def fense Offic III cer Office of Civil D e Defense-Departmen of Natio Defen nt onal nse R Republic o the Philippines ...»
Osaka Gas has three basic disaster prevention measures for earthquakes namely 1) preventive measure by ensuring a strong facility against earthquake; 2) emergency measure or preventing the occurrence of secondary disaster; and 3) restoration measure or early resumption of gas supply after a disaster impact.
This company is an outstanding example where safety is a priority thereby contributing to resilience of communities to disasters. Safety measures at LNG Terminals is also anchored on bolstering earthquake resistance facilities. Osaka Gas major LNG facilities including LNG tanks are earthquake proofed to withstand strong magnitude earthquakes such as magnitude 7 on the seismic intensity scale. This is one of the most notable information that none of the Osaka Gas LNG was damaged during the Great Hanshin Awaji Earthquake. But to minimize possible damage in the event of an earthquake, LNG tanks are constructed on foundations supported by hundreds of steel piles that are driven into solid earth and the tanks are of double-shell construction.
The central control rooms at LNG terminals carry out around-the-clock monitoring and operation of all processes from receipt of LNG to production and delivery of gas.
Emergency detectors are installed throughout the LNG terminal. Should a detector detect an abnormality, an alarm will be sounded in the central control room and staff will rush to the scene and respond to the problem.
To safeguard the tanks against natural disasters, surrounding dikes are built around the LNG tanks to prevent LNG from flowing out in case of an unexpected LNG spill. Even if LNG spills out inside the dike, high-expansion foam discharge devices and water curtain facilities can prevent LNG from spreading.
In order to make the gas pipelines earthquake proof, Osaka Gas uses polyethylene (PE) pipes when installing new low-pressure pipes. These PE pipes have high earthquake resistance and corrosion resistance. PE pipes had almost no damage during the Great Hanshin-Awaji Earthquake. Now over 80% of Osaka Gas pipeline network has been earthquake-proofed.
Osaka Gas is currently promoting the widespread use of micro-computer controlled meters. With the use of micro-computer controlled meters, gas use is monitored around the clock. The microcomputer controlled meter automatically shuts off the gas supply should it detect an earthquake or large gas leak. One hundred percent of residential customers in Osaka Gas supply area are now equipped with the meters. This is the best example of preventing secondary hazard such as fire after the occurrence of a strong earthquake.
The company has installed seismographs and remote monitoring devices throughout its service areas to enable quick determination of seismic intensity and collection of information on state of gas supply. To prevent secondary disaster, the company has divided its supply area into blocks. In each block, an automated seismic shutoff devices and remote shutoff devices are strategically installed. If a disaster occurs and the gas supply is temporarily shut off, working on each subdivided block will make it possible to restore service promptly while ensuring safety.
Osaka Gas Company actively conducts joint disaster drills with local governments and fire departments with the aim of improving security awareness and disaster response capabilities of all its employees. The company also conducts education and training programs to ensure that advanced knowledge and skills regarding safety and disaster prevention are passed on to future generations.
The company believes that through safety drills will lead to an effective and efficient response to an emergency. Osaka Gas conducts more that 2,000 disaster drills (including small-scale drills for a few people) yearly at its business bases such as at the Senboku and Himeji LNG Terminals and Pipeline Business Units. This is done to ensure that all employees can exercise prompt and proper judgment in the event of a disaster such as earthquake and fire. The company has also concluded certain disaster risk reduction and management agreements with local governments and companies including the conduct of joint disaster response drills.
In October 2011, Hyogo Prefecture Comprehensive Disaster Drill for Petrochemical Complexes, etc., organized by the Hyogo Prefectural Government, was held at the Himeji LNG Terminal. The comprehensive disaster drill for petrochemical complexes is held annually. The 2011 drill was conducted under the scenario based on the probability of major earthquakes, causing damage to land and sea. A total of 140 people from 13 organizations participated in the drill, including the Maritime Safety Agency, Self Defense Force, fire departments and police stations, and neighborhood companies. In the drill, which simulated an oil spill from heavy oil tanks and ensuing fire, our LNG terminal workers practiced their initial response procedures. This annual drill helps reinforce collaboration among participating organizations.
The company is also committed to passing on advanced knowledge and skills for safety and disaster prevention to future generations. Osaka Gas strives to develop human resources with advanced knowledge and skills in safety and disaster prevention. In preparation for the retirement of experienced technicians, the Human Resources Development Center of the Pipeline Business Unit launched a new human resources development system in fiscal 2008. To establish a system that does not allow an accident to happen (i.e. safety culture), the Center has been promoting human resources development in an organized, systematic manner, and "know-why" education to ensure that employees understand the meaning and theoretical background of operational procedures. In an effort to enhance employees' safety awareness and performance, an experience-based training facility has been established that enables them to simulate a variety of problems that have occurred in the past, so that lessons learned from past failures are shared among employees.
Various training courses are also offered by the Human Resources Growth Center, which provides safety and disaster prevention education to LNG terminal workers, and the Human Resources Development Centers of the Residential Energy Business Unit and the Commercial & Industrial Energy Business Unit, which provide services relating to gas pipes and gas appliances at customer sites.
E. Protecting Communities from Flood: The Management of Lake Biwa Lake Biwa is one of the oldest lakes in the world and is a habitat for a diversity of creatures. According to the Lake Biwa River Office data, Lake Biwa is one of the oldest lakes in the world which was formed four million years ago in Ueno Basin, Mie Prefecture, eventually shifting until it reached its current location. With its rich ecosystem, Lake Biwa, was designated as a registered wetland under Ramsar Convention or the Convention on Wetlands of International Importance especially as Waterfowl Habitat in June 2003. The lake has an area of 670 square kilometer, one-sixth of Shiga Prefecture, and a volume of 27.5 billion cubic meters.
The weir in Lake Biwa reduces flood damage and secures water for living and industrial use. The lake regulates pond for flood control in the downstream and serves as reservoir in times of drought. Lake Biwa provides an important source of water for 17 million people in Kyoto, Osaka, and Kobe. About 60% of the flow quantity in the downstream of Yodo River depends on the discharge water of Lake Biwa.
The Seta River Weir was constructed because of a devastating flood in the late 19th century. This was then an important project especially on its set up along with the dredging of Sea river among Yodo River Improvement Construction Works in 1900 to
1908. The improvement of the flow by dredging Seta river causes a flood in the downstream of Yodo river. To reconcile the conflicting interests of both communities, upstream and downstream communities, the Seta River Weir was constructed. The weir was also designed to control water level of the Lake Biwa, the reduction of flood discharge, and the upkeep of the normal function and the flow in Uji and Yodo rivers which are the downstreams of the weir. The weir likewise strategically controls the supply of public water, industrial water, and agricultural water. The weir constructed through Yodo River Improvement Work was completed in 1905, and is called “Nango weir”. The construction the new weir in 1961 complements its ultimate purpose.
However, a part of the Nango weir is still preserved as a historical value which decorates one page of the flood control history in Seta river. The present weir consists of the main weir completed in March 1961 and the bypass channel constructed in March 1992 as part of the Lake Biwa Development Project. In September 1896, a great flood occurred in Lake Biwa basin inundating almost all the surrounding districts which lasted to more than 200 days according to records. According to the records of Lake Biwa River Office, Kinki Regional Development Bureau, Ministry of Land, Infrastructure, Transport and Tourism, the great flood which occurred in September 1896 was caused by heavy rains that continued for ten days from September 3 to 12, with a total rainfall of 1,008 mm or more than half of the annual precipitation of 1,900 mm in Shiga Prefecture, especially with torrential rains of 597 mm in a single day of September 7.
The heavy precipitation raised the water level of Lake Biwa to pus 3.76 m at the Torii River Observation Station, near Karahashi, and caused disastrous floods all around the Lake Biwa. To educate the future generations on this disaster, stone monuments were built and traces were preserved to record the flood stage. In front of the memorials, visitors can learn how devastating and terrible floods were.
Under rainfall conditions, Lake Biwa, by virtue of its terrain characteristics, is very vulnerable to flooding which could last for a long period of time. This characteristics is due to the fact that as many as 118 Class A rivers such as Ane, Ado, and Yasu rivers are flowing into Lake Biwa. It was believed that as early 8th century, communities began to tackle the problem on flooding themselves with a Buddhist priest who came up with an idea of dredging the bottom of Seta river to lower down the water level of Lake Biwa.
The then early local rulers named Tairano Kiyomori, and Hideyoshi Toyotomi of the 12th and 16th centuries respectively, tried to drain water from the lake to the Sea of Japan but In the 17th to 19th century or from 1603 to 1868, it was said that citizens living failed.
around the lake dredged the river at their own expense but said engineering work did not prevent the flooding of Lake Biwa. Suuccessive devastating floodings occurred along Lake Biwa and in 1889 paddy fields in the area were badly inundated that farmers could not plant seedlings. In 1896, the entire country of Japan suffered severe flood damages which prompted the enactment of the River Law. The River Law enabled the national government to carry out large scale river improvement projects but the Yodo River Improvement Work started 1980 based on the nation’s first river plan. From 1900 to 2009, the Yodo River improvement work is dredging of Seta River including its development. The comprehensive development projects of Lake Biwa is not only from the viewpoint of flood prevention and water utilization but also from the perspective of environmental preservation and had been implemented for 25 years from 1972 to 1996.
There are three pillars on the project plan namely, preservation measure to conserve the water quality of the lake and its affluent environment, the flood control measure to address the problem on floods, and the water use measure to utilize effectively the water of Lake Biwa. The projects carried out by the Water Resources Development Public Corporation or presently called Japan Water Agency are the lake embankments, drainage from protected lowland, southern lake dredging, the Seta River dredging, improvement of the Seta River weir, and management facilities. The national or municipal government carry out the construction of dams, Sabo works, erosion control, afforestation and forest road, sewage works, night soil treatment, making the land public belongings for preservation of the national environment, facilities for provision of the environment for livestock, facilities for processing drainage in agricultural villages, garbage processing facilities and facilities for monitoring water quality. Project conducted by both Japan Water Agency and the national and municipal government are construction and management of roads, rivers, water supply, industrial water supply, land improvement, fisheries, ports and harbors, fishery ports, urban parks, and facilities for natural parks.
Heavy rains for long period brings up the water level at the Uji, Kizu, Katsura and Yodo rivers. Increase in Yodo river discharge increases the water level of Lake Biwa. As the water level continues to rise, the weir is opened to bring the water level down. On August 17, 2007, the decision of the Yodo River System Improvement Basic Policy was established and on March 31, 2009, the Decision of the Yodo River System Improvement Plan was established.
In the past, the water at Yodo river was mainly used for agricultural water and transportation services. In 1890, the first water utilization canal of Lake Biwa was constructed which paved the way for the hydroelectric power generation at Uji river, transportation, irrigation and public water usage. The first term Yodo River Water Control Work was implemented to cope with the increasing demand of water in line with the development of industrial economy, and with the control of water level of Lake Biwa, efficient and effective water utilization and management became possible. With the enactment of Water Resource Development Promotion Law in 1961, various projects were conducted under the Yodo River Basin Water Resource Development Basic Plan or the so called “Yodo River Full Plan” to cope with the demands of social and economic recovery.
Structure and Function of Seta River Weir