Test run

Tehri Dam, Uttarakhand, India

Our first run. It checked that our processing works from start to finish before we did a full study. It used ready-made, low-detail satellite products from the COMET-LiCSAR service and a simple version of our method.

Rough and not checked

This run only tests the method. It makes no claim that the dam is moving. Most of the up-and-down swing in the chart, about ±30 mm, follows the seasons. That is most likely weather affecting the signal, not the structure moving.

Left: map of how fast the ground moved around Tehri Dam, between -8 and +8 mm a year. Right: chart of movement over time at the fastest-moving point and the dam crest, showing a seasonal swing. — Left: how fast the ground moved around Tehri Dam, Jan 2025 – Jun 2026. Blue is toward the satellite, red is away. Right: movement over time at the fastest-moving point and at the dam crest.

Lessons

What the test taught us

Weather is the biggest problem in mountain valleys. Steep slopes and monsoon moisture create seasonal swings as big as real movement. Correcting for weather is essential.
Ready-made products are a quick first look, not an answer. They are good enough to test our setup, but too coarse to monitor a structure.
Dams need sharper, targeted processing. Measuring the crest and face needs full-detail, point-by-point processing. That is the approach behind the Dalli-Rajhara case study.

Source images: COMET-LiCSAR (contains modified Copernicus Sentinel data 2025–2026).