Every year, as comprehensive flood preparedness kicks off across the Yangtze River Basin, the Hydrological Telemetry Team of the Three Gorges Cascade Dispatch & Communication Center, China Three Gorges Corporation (“CTG”), embarks on its annual field inspection campaign. Rooted along the frontlines of rivers, the team safeguards the “nerve endings” of the basin’s hydrometeorological sensing system. Splitting into multiple groups, the team members head for five provinces and municipalities: Hubei, Chongqing, Guizhou, Sichuan and Yunnan. They travel deep into mountainous reservoir areas and riverside tidal flats with one single objective: to keep every hydrometeorological telemetry station “keen-sighted and sharp-eared” during the flood season and accurately capture every subtle fluctuation of the rivers.

Hydrometeorological telemetry stations distributed over the upper Yangtze River may look ordinary, yet they act as the “far-sighted eyes and sensitive ears” for flood control that safeguard the safety of the Yangtze River. Operating round the clock, the equipment records water level variations and rainfall changes, aggregates massive volumes of scattered hydrometeorological data in real time, and forms a “smart information network” covering the river basin to support flood regulation of cascade reservoirs. To consolidate this defense line for flood control monitoring, inspection team members trek across mountains and rivers all year round. They follow the requirement to visit every station, inspect every site and check every item, leaving no blind zones and neglecting no single piece of equipment.

At a hydrological station in Yichang City, Hubei Province, inspector XIA Zhe and his colleague are conducting a comprehensive and refined inspection. On the rooftop stands a tipping bucket rain gauge bathed in sunlight. While clearing fine debris inside the bucket, XIA Zhe shares operational experience with his young colleague beside him: “Once the bucket fills up with rainwater, it tips over. The magnet cuts the reed switch to generate a pulse signal, through which rainfall data of 0.5 mm are captured.” After verifying flexible movement of the tipping bucket, he wipes the solar panels and tests the battery voltage to guarantee uninterrupted power supply for the equipment even during successive cloudy and rainy days. Having finished rooftop work, the two walk over to the vertical staff gauge by the riverbank. They record readings, repeatedly compare them with data from the bubbler water level gauge, and conduct calibration and fine-tuning. The complete inspection procedure has long been etched into every team member’s mind, yet each operation must be performed with meticulous attention. Before the flood season each year, they inspect hundreds of rainfall stations and water level stations.

Field inspections are not merely a test of professional expertise, but also a trial of physical stamina and mental will. From the Tanziling Meteorological Observation Station, the highest point of the Three Gorges Dam area, to the remote, sparsely populated Jinsha River Reservoir area, wherever hydrometeorological telemetry equipment is deployed, the busy figures of inspection personnel can always be found. Under the scorching sun, they crouch beside the white thermometer screen to check temperature and humidity sensors; amid wind and rain, they trudge along muddy mountain roads to inspect communication terminals. This is not only the daily routine of XIA Zhe, but also a collective portrayal of the entire Hydrological Telemetry Team.

The team has built a multi-party collaborative O&M mechanism. Every year, it coordinates with 30 maintenance sub-centers and 36 local hydrological agencies to carry out joint operations. It also conducts unified arrangements for station inspections, equipment upgrading and renovation, spare parts inventory verification, and communication link tests, ensuring the redundancy and smooth connectivity of both primary and backup channels. The arduous field inspection journey also serves as a vivid practical training ground for the “mentorship program”. Experienced senior Party members lead young employees to traverse mountains and rivers. They teach staff calibration skills against water level gauges by the river and debug telemetry terminal modules on mountain tops. While passing on professional O&M skills and expertise, they also convey the dedication of rooting themselves in front-line posts and fulfilling duties faithfully, accelerating the growth and professional development of the young telemetry inspection and maintenance team.

Sufficient pre-flood preparations ensure ample composure throughout the flood season. Solid preliminary work enables the hydrological telemetry system to exert core functions during flood periods. At present, the system covers a total of 699 telemetry stations, with the capability to collect hydrometeorological data from all core control stations within 10 minutes. The data pass rate and equipment availability rate remain steadily above 99% all year round, far exceeding industrial standards.

During the 2024 flood season, the Yangtze River encountered its second flood. Relying on massive, high-precision data transmitted in real time by the hydrological telemetry system, forecasters accurately predicted one week in advance that the Three Gorges Reservoir would experience an incoming flood peak of over 50,000 m3/s. Through scientific water dispatch, a total of 5.28 billion m3 of floodwater was impounded, preventing water levels from exceeding the warning standard along the 147-kilometer river section from Yichang to Shashi. This remarkable achievement stems from the solid and precise pre-flood guarantee completed by the Hydrological Telemetry Team through rigorous field inspections. In addition to flood control, high-accuracy hydrometeorological data also support the optimized operation of the world’s largest clean energy corridor. In 2023, the six cascade reservoirs on the upper Yangtze River reached full capacity for the first time. Supported by accurate hydrometeorological monitoring and hydrological forecasting, sufficient water resources were reserved, strongly guaranteeing the sustained and efficient operation of clean energy generation.

As twilight falls, XIA Zhe and his colleagues take a short rest on the stone steps by the river after finishing a full day’s field work. “No matter how exhausting the work is, we must thoroughly visit, check and verify every telemetry station.” he said. This plain remark embodies the bottom-line principle adhered to by all field inspectors. Many team members, just like XIA Zhe, are Party members who always step forward and take on arduous tasks at critical moments. Backed by Party members as the core backbone, the team has kept the Party flag flying high on the front line of Yangtze River flood control through persistent dedication in wind and rain. These tireless “nerve endings” have forged an unbreakable “red defense line” with technology and hard work, safeguarding the peace of the Yangtze River.