Introduction – World Hydrography Day is celebrated every year on June 21 to spread awareness about the importance of hydrography to improve understanding and knowledge of the oceans and seas worldwide.  The main aim of this international day is to highlight the important role of hydrographers in understanding and mapping rivers, lakes, and oceans for efficient and safe navigation, rapid climate change, and environmental protection.

Hydrography is a branch or subject of applied sciences, which mainly deals with the explanation and measurement of the physical features of seas, rivers, oceans, lakes, and coastal areas.  The main responsibility of hydrographers is to predict or forecast changes in the water bodies for the safety and protection of navigation and support of all marine activities. 

History – World Hydrography Day was established by the International Hydrographic Organization (IHO) in 1921 which works on the problems of marine life. International Hydrographic Organization proposed the idea of celebrating this international day to commemorate the work of hydrographers across the world. The United Nations approved the concept of the International Hydrography Organization in 2005 and announced that World Hydrography Day is celebrated every year on June 21, which was selected to commemorate the anniversary of the International Hydrographic Organization. Thus, World Hydrography Day was first celebrated on June 21, 2006, all around the world.

Significance – Hydrography is the subject or science of describing and measuring the physical features of huge water bodies including oceans, seas, rivers, and many more Hydrographic surveys help in providing important data on the tides, climate change, depth, bottom type, and many more characteristics of rivers, seas, oceans and many more water bodies. This data may be beneficial in making nautical charts that are indispensable to avoid potential hazards and save navigation at huge water bodies such as oceans, seas, rivers, and many more.

The hydrographic data is also important for resource management and environmental protection. It is also essential for maintaining biodiversity, protecting ecosystems, and ensuring of the long-term health of waterways, oceans, seas, rivers, and many water bodies worldwide. The main work of hydrographers is to identify and predict the effect of human activities on the environment, make strategies for sustainable resource management, and protect marine habitats by understanding the physical features of huge water bodies. Thus, the main goal of this global day is to raise awareness about the safe navigation and marine practices of sailors worldwide.

This International Day provides an opportunity to share the importance of hydrography and honors the work of hydrographers all around the world. Several activities to celebrate this international day including conferences, workshops, group discussions, public events, and many more across the world.