Hydrology is the scientific study of the movement, distribution, and quality of water on Earth and other planets, including the water cycle, water resources and environmental watershed sustainability. A practitioner of hydrology is a hydrologist, working within the fields of earth or environmental science, physical geography, geology or civil and environmental engineering. Using various analytical methods and scientific techniques, they collect and analyze Information to help solve water related problems such as environmental preservation, natural disasters, and water management. Such Information is known as Hydrological Data.
Hydrological data has to be obtained from the data owner. National agencies have networks throughout India, and web-sites that provide data to download and information on the meta-data for detailed data-sets held. In addition, States have more detailed monitoring networks, and data from these sources have to be obtained from the State themselves.
The National data owners are India Meteorological Department (IMD) for climate and rainfall data, the Central Water Commission (CWC) for information in lakes and rivers (and they also have some climate data) and Central Ground Water Board (CGWB). The IMD database can be accessed through their web-site: imd.gov.in . Recent data is available free to download, but long time-series for data are sold. Details are provided on the web-site.
Central Water Commission Data Dissemination portal is the WRIS system, accessed through the web-site: india-wris.nrsc.gov.in This site continues to be developed, and it is intended to allow most persons wishing to use hydrological data for India catchments to download data needed directly. There are some restrictions on data availability, and more detail is available on the web-site and in the data dissemination policy of MoWR. Basically, unclassified river basins have data that can be downloaded, but those classified basins (international rivers) permission to use data is needed, forms have to be filled (see Data Dissemination Policy for the procedure) and fees may be applicable. Central Ground Water Board data is basically accessible through the web portal: gis2.nic.in/cgwb
For data from networks operated by the States, the Hydrology Project web-sites can be used as a preliminary source of information. Usually, at the moment, personal visits are needed to State Data Centres, but this does vary from State to State. Contact details for the key persons are provided within the web-sites.