18-12, Nishiochiai 2-chome,
Shinjuku-ku, Tokyo 161-8575, Japan
Phone: +81-3-5906-0211
FAX: +81-3-5906-0112

Water Resource Development

BACKGROUND & PURPOSE OF PROJECT

For this project we carried out investigations regarding type comparisons and design conditions and drew up execution designs it terms of water-intake installations and water-use discharge equipment to be used in the Obara Dam.

CHARACTERISTICS, CONCEPT, STANCE & SKILLS OF PROJECT

For this project, we adopted a "continuous siphon type water-intake installation", which is a new type of selective water-intake installation that uses air to stop water. This installation can intake water through the selected water-intake pipe without the use of a steel gate or a separate switchgear.

We adopted the use of a continuous siphon type water-intake installation to operate as a selective water-intake installation, a worldwide first. We conducted analysis using the finite element method to verify that the continuous siphon type water-intake installation could safely bear operating loads. Water-use discharge equipment was split into two 2 discharge gate systems (for large and small amounts of water) in order to ensure the safe discharge of predetermined water loads.

EFFECT OF PROJECT

Construction costs were reduced by approx. 50% through the adoption of the continuous siphon type water-intake installation. This also saved on labor with regards to maintenance, and the impact on the surrounding scenery was lessened by eliminating protruding structures on the dam crest.