Support and development of international database on hydrology of lakes and reservoirs are most important HYDROLARE´s functions.
Formation of the HYDROLARE database had been begun with data of the former Soviet Union available at the State Hydrological Institute (SHI). It was data on 697 lakes and reservoirs and 1242 gauging stations (both operating and closed down).
Since 2010 the process of adding and updating of data on former Soviet Union states has started, and also acquisition of data from other WMO members which agreed to collaborate with HYDROLARE (See Data acquisition and accept).
Database content and structure
When the composition of the database was being designed, the significance of data for users, availability of data and the willingness of WMO member-countries to provide their HYDROLARE were being considered. Capabilities of HYDROLARE to collect, store and process data were also taken into account.
The first stage structure of database was proposed, discussed and accepted on the first meeting of the HYDROLARE International Steering Committee in June 2007. This structure includes:
"passport data" (metadata) on lakes and reservoirs;
"passport data" (metadata) on gauging stations;
annual data on regime of lakes and reservoirs, including water level, water temperature and ice thickness.
"Passport data" on a lake or reservoir comprise water body code, name and type, its location (coordinates of the centre and country code), length, width, elevation, mean and maximum depth, surface area and volume, catchment area. For reservoirs, design specifications are also indicated, such as normal storage level (NSL), dead storage level (DSL), surface areas and storages at NSL and DSL, reservoir regulation type, start of filling and start of operation (years).
"Passport data" on a gauging station comprise station code and name, its location (coordinates, water body code and country code), gauge datum, operation period, observation program, name of data provider.
Annual data at stations are presented as follows:
mean monthly water level;
mean monthly water temperature;
highest water temperature per year, its first and last dates, number of cases;
maximum ice thickness per year, its first and last dates, number of cases.
In addition there are provided following water body averaged data:
mean monthly water level;
water level at the first date of each month.
Moreover, the database contains information on WMO member-countries and data holders.
The HYDROLARE encoding system is based on six WMO geographical Regions, each of which has Subregions. Each water body has been assigned a numerical code of a constant length (7 positions)
T Type of water body;
R Code of WMO Region;
SS Code of WMO Subregion;
NNN Number in WMO Subregion.
Each gauging station has been assigned a 9-position code, the first seven positions indicating code of a water body and the last two the gauging station number (number assignment on a first-come basis, in case of simultaneous income by the date of its opening).
Database management system (DBMS) Firebird was chosen as the main software for HYDROLARE database.