Hydrological Data Sharing is a key for Sustainable Development and building Early Warning Systems
Authors: Korhonen Johanna , Otieno Washington , Berod Dominique 
Published: February 2023

There are several factors increasing pressure on water resources such as demographic, economic, social, and climatic changes, in addition to the growing demand for energy, food, and water. Water-related hazards, such as floods and droughts, are affecting millions of people&#8217;s lives and will become more frequent, and the need for early warning systems is growing and is being addressed by UN Early Warnings for All initiative. Water is the 6th of the 17 Sustainable Development Goals (SDGs) and impacts on 15 other SDGs. There is a growing demand for water by different sectors.Responding to the above water challenges and related hazards demands hydrological data that is findable, accessible, interoperable, and reusable, sufficient, and useful. Unfortunately, in most countries and regions, management of water resources is mostly addressed without adequate consideration of the inter-sectoral and transboundary implications of planned developments or decisions on different sectors. This is due to lack or inadequate management and exchange of reliable data among various sectors. It is essential that the management and sharing of hydrological data are performed effectively to maximize the benefits of data collection and optimize data reuse, and thus get a return on investment.Data exchange is still a challenge in hydrology from both the technological and policy perspective. The technology challenges include sparse measuring networks and lack of automatic data transmission, inadequate data quality control systems, heterogeneous and incompatible standards and protocols for data and metadata storage and exchange, and the inability to openly publish and maintain data and metadata in a publicly interoperable way. The policy challenges are often related to restrictive national legislation and financial consideration on data sharing. The WMO Unified Data Policy adopted in 2021 and the Earth System approach will help to address some of the issues, while the relevant integrated and interoperable data management and access tools, will support the technical aspects.WMO programmes promote exchange of Earth System data. WHOS (WMO Hydrological Observing System) is the hydrological part of the WIS providing data sharing solutions. It is a system of systems supporting interoperable hydrological data exchange using open standards and web services, and harmonizing the data to meet specific user needs.The goal of WHOS is to make hydrological data accessible through the use of open standards and free open-source tools for the harmonization of data, metadata, protocols, and vocabularies. Due to the diversity in the use of hydrological data and heterogeneous data sources, their effective exchange requires the implementation of interoperability enablers and data exchange mechanisms such as WHOS Discovery and Access Broker (DAB) technology, and development of hydrological terminologiesand Metadata Data Profiles.The WHOS has been implemented in La Plata Basin, Arctic Region, Dominican Republic, UK, and SAVA River Basin. Those regions benefit from a platform that enables interoperable data sharing among different stakeholders and water resources management. With new countries connecting to WHOS each year, there will be a notable improvement in global, regional and national implementation of Early Warning systems and other projects.