Open water data in India: India-WRIS and IMD

A student needs ten years of river levels for a thesis. A district engineer wants to know whether last night's rain was unusual. A consultant needs groundwater levels for a village. All three type the same thing into a search engine: India WRIS. The portal is the main public door to Indian water data, but it is one door among several, and each source has its own rules about what you may download, what you must request and what you should check before trusting a number. This article explains what is available, where it comes from and how to use it.

What is India-WRIS?

India-WRIS (India Water Resources Information System) is a web portal that brings water data from several government agencies into one place. It began in 2009 as a joint project of the Central Water Commission (CWC), the Ministry of Jal Shakti and the National Remote Sensing Centre of ISRO [2]. The Central Ground Water Board (CGWB) describes it as an integrated platform for all water-related information, maintained by the National Water Informatics Centre (NWIC) [4].

India-WRIS does not collect data itself. Field agencies do, and the data are fed into an internal database that only authorised users can enter, the Water Information and Management System (WIMS). India-WRIS is the public face, where the data are "finally shared to end users" [4]. CWC lists the portal's map content as 12 major information systems in five groups: watershed atlas, administrative layers, water resources projects, thematic layers and environmental data [2]. The time-series data most readers want, such as river levels and groundwater levels, sit alongside these maps.

What data can you get, and from whom?

No single agency holds everything. The useful habit is to ask which agency measures the thing you need.

How do I download India-WRIS rainfall data?

The India-WRIS dashboards show rainfall alongside river levels, water bodies and groundwater. For long rainfall and climate records, however, the primary source is IMD. IMD's Data Supply Portal lists a Climate Data Service that is open to all, with climate tables, historical extremes, gridded climatological data and free data series. Other observation, radar and satellite data need an enrolled account, and data charges were revised in the portal's version 4.0; the cost depends on the data and the user [5]. Check the portal's cost page for your case, and note its disclaimer that reproducing published material for commercial purposes needs permission from the competent authority [5].

How do I download India-WRIS groundwater data?

Groundwater is the best-documented case, because CGWB publishes how it collects the data [4]:

• Manual network. CGWB monitors groundwater levels across the country four times a year, in March to May (pre-monsoon), August, November and January, at about 25,000 stations called National Hydrograph Network Stations. These are open dug wells and purpose-built tube wells called piezometers.
• Automatic network. Under the National Hydrology Project, CGWB is installing digital water level recorders with telemetry; 5,260 are proposed. Six-hourly readings go to WIMS and then to India-WRIS.
• State and programme networks. State governments run their own wells, and recorders are also being fitted under Atal Bhujal Yojana.
• Yearbooks and compiled files. CGWB publishes state and national groundwater yearbooks, and has compiled the January, pre-monsoon and August level data since 1994 for download.

A groundwater level is reported as depth below ground level, so a rising water table shows as a falling number. To compare wells, convert to elevation: ground-surface elevation minus depth to water. For example (illustrative), a well whose ground surface is at 850.0 m above mean sea level and whose water is 12.4 m down has a water-table elevation of 850.0 − 12.4 = 837.6 m. For how telemetry changes this picture, see groundwater level monitoring with telemetry.

What does IMD's gridded rainfall data show?

Many studies use IMD's gridded rainfall instead of single gauges. The standard daily product has a resolution of 0.25° × 0.25° and covers 1901 to 2010 in its original form. It was built from daily records at 6,955 rain-gauge stations after quality control, and compared with four other gridded sets [6]. Because it is built from gauges, it is often used as the observed reference. In our study comparing three satellite rainfall products with IMD's 0.25° gauge-based data across India, we found that how well the satellite products captured extremes varied across India [7]. A grid is a statistical surface, not a measurement at your location.

Here is what a cell means on the ground (illustrative arithmetic, near 31.5° N, close to the latitude of Mandi). A degree of latitude is about 111 km, so 0.25° is about 27.8 km. A degree of longitude shrinks by the cosine of latitude, so 0.25° is about 111.3 × 0.853 × 0.25 ≈ 23.7 km. The cell covers roughly 27.8 × 23.7 ≈ 660 km². In a Himalayan valley, where rainfall can differ sharply between a valley floor and a ridge a few kilometres away, a single grid value cannot represent a small catchment. See how many rain gauges a district needs and India's AWS and rain-gauge networks.

Why is some data free and some on request?

India's National Data Sharing and Accessibility Policy (NDSAP), issued by the Department of Science and Technology in 2012, applies to shareable, non-sensitive data produced with public funds by Government of India bodies. It defines three types of access [1]:

1. Open access: easy, timely and web-based, with no registration or authorisation.
2. Registered access: available to recognised institutions or users through a defined procedure.
3. Restricted access: data declared restricted by Government of India policies, available only under authorisation.

Each department also prepares a "negative list" of data that are not shareable. The policy says shareable data are provided on an "as-is where-is" basis, that users should acknowledge the ministry or department in all publications, and that metadata are to be placed on data.gov.in [1].

The water agencies follow the same logic. CWC releases hydrological data under the Hydro-Meteorological Data Dissemination Policy, 2018. For data that are not freely downloadable, you send a Hydrological Data Request Form and a secrecy undertaking to the concerned field Chief Engineer, stating the purpose, study area, duration and method. Data go to central and state bodies, academic institutions and research organisations in India after the justification is checked, and any postal or media charges are notified on approval [3]. A request is a normal route, not a refusal, but allow time for it.

How to use these data well

Open data are not the same as ready-to-use data. A short routine avoids most of the usual problems:

1. Read the metadata. Find out who measured the data, how, at what interval and over which period. The NDSAP expects metadata to cover citation, access and contact information [1].
2. Check the datum. A river level may be relative to the gauge zero or to mean sea level. See gauge zero, datum and benchmarks.
3. Look for spikes, gaps and flat lines before computing anything. See data quality control for hydromet time series.
4. Match the time basis. A daily rainfall total and a daily river level (one reading or a mean?) are different things. Note which you have.
5. Respect resolution. Grids and sparse wells describe regions, not sites.
6. Cite the source and the access date. The policy asks for acknowledgement [1], and portals change.
7. Keep raw downloads as read-only copies in an open format such as CSV; see open formats for hydrological data.

Where open data stop

Open portals give you the regional picture and history. They rarely give you a reading from the bridge near your village, at ten-minute resolution, now. Official stations are few, and for a flash-flood catchment a gauge in the next district is not a warning. Open data work best as context, for background rainfall, past events and baseline groundwater, while local sensors supply what is happening at the site. Understanding measurement uncertainty lets you combine the two honestly.

Key points

• India-WRIS is the public portal of a system maintained by NWIC; it shares data collected by agencies such as CWC and CGWB.
• IMD is the source for rainfall and climate data; some series are open to all, others need enrolment and may carry charges.
• CGWB measures groundwater four times a year at about 25,000 stations, plus telemetric recorders; levels are depth below ground, so convert before comparing wells.
• NDSAP defines open, registered and restricted access; CWC data that are not freely downloadable are released on request under its 2018 policy.
• A 0.25° rainfall cell covers hundreds of square kilometres, so it cannot stand in for a gauge in a small hill catchment.
• Always check metadata, datum, gaps and time basis, and cite the source.

Where ClimMaTech fits

Open datasets tell you what happened on average and in the past; they cannot tell a district what the river is doing now. At ClimMaTech we build the field side: monitoring stations that record on board and report over GSM to our cloud platform, Visiflow (Device Cloud). Our real-time data acquisition and hydromet telemetry solution describes how station data can sit beside the open national datasets described here.

References

1. Department of Science and Technology, Government of India, National Data Sharing and Accessibility Policy (NDSAP) 2012, March 2012. PDF (state-government hosted copy)
2. Central Water Commission, Water Resources Information System (WRIS), official page. cwc.gov.in
3. Central Water Commission, Hydrological Data (release of data under the Hydro-Meteorological Data Dissemination Policy, 2018), official page. cwc.gov.in
4. Central Ground Water Board, Ministry of Jal Shakti, Ground Water Level Monitoring (monitoring networks, WIMS and India-WRIS), official page. cgwb.gov.in
5. India Meteorological Department, Data Supply Portal. dsp.imdpune.gov.in
6. D. S. Pai, L. Sridhar, M. Rajeevan, O. P. Sreejith, N. S. Satbhai, B. Mukhopadhyay, Development of a new high spatial resolution (0.25° × 0.25°) long period (1901-2010) daily gridded rainfall data set over India and its comparison with existing data sets over the region, Mausam 65(1), 1-18, 2014. doi:10.54302/mausam.v65i1.851
7. V. Gupta, M. K. Jain, P. K. Singh, V. Singh, An assessment of global satellite-based precipitation datasets in capturing precipitation extremes: a comparison with observed precipitation dataset in India, International Journal of Climatology 40(8), 3667-3688, 2020. doi:10.1002/joc.6419