Water conservancy facilities require reliable position feedback under humidity, splashing, sediment, and temporary immersion. A corrosion-resistant linear displacement sensor converts the linear movement of gates, penstocks, valves, or dams into a stable electrical signal. Most modern models use a non-contact magnetostrictive or LVDT principle to avoid wiper wear. In a magnetostrictive sensor, a current pulse travels along a waveguide and creates an axial magnetic field. A permanent position magnet attached to the moving part interacts with this field and generates a torsional strain wave. The wave returns at a fixed speed, and the time difference between transmit and echo is proportional to displacement. An LVDT design uses a movable iron core and primary/secondary coils; core movement changes differential induced voltage, which is demodulated into distance. The electronics then filter, linearize, and convert the signal into 4-20 mA, 0-10 V, or RS485 output for PLC/SCADA systems. For water conservancy, the housing is sealed to IP68 and made from 316L stainless steel, PVDF, or PTFE-coated parts. Welded flanges, cable glands, and pressure-balanced connectors resist corrosion and leakage. Temperature compensation and surge protection ensure accuracy in outdoor dams and pump stations. Regular calibration keeps long-term stability. Its compact probe fits gate frames and penstock brackets, while shielded cables reduce electromagnetic interference in pump stations. Routine zero and span checks support safe reservoir operation.