PHE dept launches first scientific flow test to strengthen Gangtok’s water distribution system

LALIT DAHAL

Data-driven study to improve equitable supply, modernise infrastructure and prepare the capital for future demand

GANGTOK,: Seeking to address recurring water shortages through scientific planning, the State Public Health Engineering (PHE) department has launched the first comprehensive flow test of Gangtok’s water distribution network, marking a significant step towards data-driven water management in the State capital.

The exercise aims to study how water moves through the city’s reservoirs and pipelines, identify distribution imbalances, calibrate control valves and generate technical data that will guide future infrastructure development and ensure a more equitable supply, particularly during the lean winter months.

Speaking to media, PHE secretary Sailendra Sharma said the initiative is being undertaken in line with Chief Minister Prem Singh Tamang’s vision of improving the quality of life by strengthening essential public services through scientific planning and modern infrastructure.

He said Gangtok has witnessed rapid urban expansion over the years, with growing population, new residential areas and changing consumption patterns significantly increasing the demand for drinking water.

“While the department has regularly assessed water demand, this is the first comprehensive scientific study of Gangtok’s entire distribution network. The data generated through this exercise will help us plan future infrastructure, optimise water distribution and build a more efficient and resilient supply system,” Sharma said.

He added that the initiative is being carried out under the continuous guidance of PHE minister Sonam Lama, with its progress being reviewed regularly to ensure systematic implementation.

During a field visit to the Chorten Zonal Tank, engineers demonstrated the testing process, which involves measuring water levels before and after operating distribution valves to calculate inflow and outflow in litres per hour. The exercise enables engineers to understand the actual hydraulic behaviour of each reservoir and assess whether water is being distributed proportionately across different service areas.

According to junior engineers Chungkila Bhutia and Mandira Rai, the data collected will help determine the actual demand and supply at each zonal reservoir and support more balanced water distribution during the dry season. They said the monsoon provides the ideal window for conducting such tests, as sufficient water is available to carry out controlled observations without causing prolonged inconvenience to consumers.

Explaining the technical significance of the study, chief engineer Sonam PaldenWangdi said Gangtok’s water supply system operates entirely on gravity. Water sourced from Rateychu is treated before being stored at Selep, the city’s primary storage facility, from where it flows to around 25 zonal reservoirs before being distributed to households.

“The issue is not always the availability of water. Even during the monsoon, when our main storage reservoirs are full, some areas continue to report shortages. That indicates the need to scientifically understand how water is moving through the distribution network before implementing corrective measures,” Wangdi said.

A key component of the exercise is the calibration of control valves, which regulate the volume of water supplied to different localities. Using field measurements, engineers will determine the optimum valve settings to ensure a more balanced and equitable distribution across the city.

The study is also expected to identify ageing pipelines, areas requiring network augmentation and locations where future infrastructure investments will be most effective. Simultaneously, PHE department is working to strengthen the Rateychu water source through the proposed installation of a Tyrolean Weir intake system, which is expected to improve water collection efficiency while reducing sediment-related challenges.

Officials said the findings will further support implementation of the proposed Water Supply Act 2025, which seeks to strengthen regulation of the drinking water system, including the regularisation of unauthorised water connections.

While the department has not yet disclosed the detailed findings of the ongoing study, officials said the data is currently undergoing technical evaluation before operational decisions are taken.

More than a routine engineering exercise, the flow test represents a shift towards evidence-based management of Gangtok’s water supply system. By combining scientific measurements with long-term planning, PHED hopes to improve distribution efficiency, strengthen ageing infrastructure and build a more reliable water supply network capable of meeting the demands of a rapidly growing capital.