Order Received for Renovation of Otsuka Drainage Pumping Station in Yamanashi Prefecture [Orders Received in October 2025]

The Otsuka Drainage Pumping Station is located in Ichikawamisato-cho, Yamanashi Prefecture, a town famous for its great scenic hot springs. For over 45 years, this facility has played a vital role in protecting the lives of local residents and agricultural land.

Originally constructed in 1979, the station is equipped with two 900 mm diameter horizontal mixed-flow pumps to prevent flooding during heavy rains. However, due to long-term operation, the equipment has aged, leading to concerns about future drainage performance. Additionally, recent flooding analysis based on climate change and land development showed that increasing the drainage capacity is now necessary to meet current environmental demands.

To address these challenges, we conducted a health survey of the pump interiors using 360-degree cameras and endoscopes during the design phase. The results confirmed that the pump bodies remain in good condition. Consequently, we determined that the facility can continue to be used through partial renewals and overhauls rather than a full replacement or rebuilding the concrete foundations, which helps to minimize costs. We also confirmed that by manufacturing new rotors and increasing their rotation speed, we can achieve the requested increase in discharge volume.

Furthermore, we will convert the pumps from the conventional gland packing system to a mechanical seal system. This modification aims to improve maintainability and reduce the labor required for inspections. In addition to the pumps, this project includes updating the diesel engines, gearboxes, and electrical systems. Since construction will take place while keeping the existing equipment operational, we will proceed with the utmost care regarding scheduling and safety to ensure that drainage functions remain ready for immediate use
during rainfall.