First Global Map Reveals Massive Impact of Tidal Pulses on Over 175,000 Kilometers of Coastal Rivers Worldwide

Technical University of Munich releases the first global map showing how tides travel inland, affecting 725 million people and 175,000km of rivers.

By: AXL Media

Published: Mar 18, 2026, 3:04 PM EDT

Source: Information for this report was sourced from Technical University of Munich

Mapping the Hidden Reach of Ocean Tides

Ocean tides do not stop at the coastline; their periodic fluctuations carry significant energy upstream into inland river systems, a phenomenon known as a tidal pulse. Until now, a global and accurate overview of where these pulses occur and how far they travel had never been established. A research team led by the Technical University of Munich (TUM) has closed this data gap by conducting the first global evaluation of coastal rivers using high-resolution satellite data. The findings, published in the journal Nature, provide a vital tool for understanding the intersection of oceanic and riverine hydrology.

A Vital Resource for Global Flood Protection

The newly developed interactive map allows researchers to track exactly where, when, and how high tides propagate in coastal rivers. This information is critical for the more than 725 million people worldwide who live in regions directly influenced by river tides. For these populations, the tidal pulse is a primary factor in both sudden flooding events and the long-term availability of freshwater. By localizing the extent of these river tides, the TUM research team provides a necessary foundation for local governments to implement protective measures and adapt to changing environmental conditions.

Comprehensive Analysis of 3,000 Global Waterways

The research team evaluated data from more than 3,000 rivers across the globe, creating the most comprehensive database of tidal pulses to date. The study determined that over 175,000 kilometers of coastal rivers are significantly influenced by tidal activity. The reach of these pulses varies dramatically by geography; for instance, in the Amazon River, the tidal pulse can be detected up to 892 kilometers upstream from the river's mouth at the ocean. This data quantifies the massive scale at which the ocean dictates the behavior of inland freshwater systems.