Waterworks
2025
Located in the heart of Yunnan Province in southwestern China, the city of Yuxi is an industrial and ecological hub surrounded by three vital freshwater lakes: Fuxian, Xingyun, and Qilu.
In recent years, these lakes have suffered from declining water levels and increasing pollution, threatening both the environment and the communities that rely on them.
To address this, the Yuxi East Area Bulk Water Supply Project, a.k.a. the “Three Lakes Project”, was established with a total investment of 1.89 billion Yuan (approx. US$263 million). The project aimed to deliver clean spring water from Dalongtan Spring to ecologically improve the lakes’ water and ensure water supply for rural areas, as well as irrigation needs and industrial development of over 1.5 million residents across five administrative districts. In doing so, the project fosters environmental sustainability and contributes to the preservation of natural ecosystems in the region.
Managing Extreme Elevation and Surge Risk
The project required lifting water across a 941-meter elevation from the Dalongtan spring to uphill reservoir. In order to achieve this, a series of three pump stations were designed and built. Each pumping station composed of six parallel high-capacity pumps (four of which active at a time), delivering water through 1,200 mm metal pipeline over a total distance of more than 6.5 kilometers.
The table contains the main technical info about the system:
| System Parameter | 1st Pump Station | 2nd Pump Station | 3rd Pump Station |
| Number of Pumps | 6 (4 Active + 2 Standby) | ||
| Single Pump Flowrate (m^3/h) | 2250 | ||
| Total Flowrate (m^3/h) | 9000 | ||
| Pump Head (m) | 237 | 356 | 356 |
| Mainline Pipe Diameter (mm) | 1200 | ||
| Mainline Length (m) | 1415 | 2663 | 1957 |
Such a system, while powerful, is highly vulnerable to hydraulic transients, especially during power failures or emergency pump shutdowns, when fluid in motion is forced to stop or change direction suddenly. These events can trigger dangerous pressure surges, risking damage to pumps, pipelines, valves, and other system components, as well as risk for burst, flood and loss of human life. Therefore, surge protection solutions must be implemented after conducting comprehensive surge analysis.
Surge Analysis and Simulation
A detailed surge analysis was conducted by BERMAD experts. Using KY Pipe software, the simulation modeled worst-case scenario, including uncontrolled pumps trip.
The surge analysis showed:
- Results without protection: both negative & positive pressure surge occurs in all three pumping stations and along each discharge pipeline in a scenario of all pumps trip due to power failure.
- Results with surge protection solution: by implementing BERMAD’s surge protection solutions the surge phenomena is mitigated so the pressure profile present a controlled transient scenario and safe operation across all pumping stations and along each discharge pipeline.
The graph below illustrates the pressure behavior (head in meters vs. time in sec) in one of the 3 pumping stations during power failure:
- The red line presents the pressure behavior during power failure without any surge protection solution being implemented. The significant pressure surge is clearly presented.
- The green line presents the pressure behavior during power failure with BERMAD’s surge protection solution implemented.
The analysis confirmed that the selected solution of surge anticipating valves & combination air valves effectively mitigate the surge phenomena & surge risks, ensuring long-term reliability and system resilience.
Surge Anticipating valves & Combination Air Valve Integration
Surge protection solution includes surge anticipating valves & combination air valves with surge protection feature.
1. Surge Anticipating Valves Each pump station was equipped with three hydraulically operated, piston actuated off‑line surge anticipating valves for high pressure (PN40). These valves, sensing main line pressure, open in response to the pressure drop associated with abrupt pump stoppage. The pre-opened valves dissipate the returning high pressure wave, eliminating the surge.
- Pump Station #1: 3 units of WW-12”-835-M
- Pump Stations #2: 3 units of WW-16”-835-M
- Pump Stations #3: 3 units of WW-16″-835-M
2. Combination Air Valves Strategically placed along the pipeline and within the pump stations, these valves release trapped air during startup and admit air during shutdowns, preventing vacuum conditions and water column separation.
Using BERMAD Air software & the surge analysis software, BERMAD’s experts allocated and sized the required air valves in the pumping station and along the main line. The air valves are a crucial part of the complete surge protection solution allowing sufficient air intake into the main pipeline, preventing vacuum conditions and pipe collapse, mitigating the negative pressure surge during pumps trip, as well as cushioning the positive surge allowing restrained air release when the wave returns towards the pumping stations. The air valves are installed at each of the pumping stations, at high points and at critical points along the mainline, based on the surge analysis & BERMAD Air software.
Based on the analysis BERMAD recommended to install combination air valves as follows: per each pumping station, model WW-C70-AC (4”) on each pump discharge line and on each rising main model WW-C70-SP (6″). The customer accepted most of BERMAD air valves recommendations.
WHY BERMAD
The 3 lakes ecological restoration project is a perfect example of how BERMAD’s advanced, smart and efficient hydraulic control solutions aim to protect critical water systems infrastructure, even in challenging topography. By ensuring system stability and reliability, the project not only secures water delivery but also supports the ecological restoration & sustainability of Yunnan’s iconic lakes.
This case study serves as a valuable reference for similar bulk water supply systems worldwide, where elevation, distance and other environmental local issues raise the need for efficient, sustainable, and robust solutions as BERMAD designed & implemented in this outstanding project.
