“Ground Water” means the water which exist below the surface of the ground at any location. Its occurrence and movement in various litho-units underlying the State are mainly controlled by the physiographic, geological setting and structural features.
The availability of groundwater varies considerably from place to place depending on the factors such as prevailing climatic, geomorphological and hydrogeological conditions.
Even though about 88 percent of the total geographical area of the State is underlain by crystalline rocks with limited groundwater prospects, the majority of households depend groundwater for their drinking and domestic water needs.
The litho-unit which carry groundwater in extractable quantity is termed as ‘aquifer’. The major aquifers in the state are shown in the map.
Judicious and planned development of groundwater and its scientific management have become necessary to ensure its long-term sustainability.
The periodic estimation of groundwater resources is being carried out by the Groundwater Department jointly with the Central Groundwater Board
- Groundwater Resource computations have been made for 152 assessment units (blocks) spread across 14 districts of the State. In addition to that, the ground water resources of urban habitation comprising 6 Municipal Corporations, 87 Municipalities and 1 Township have been combined with the adjoining blocks based on their hydrogeological setup.
- According to the new GEC methodology (2015), the criteria of categorization of assessment unit are as follows
|Sl No||Stage of groundwater extraction||Categorization|
|2||>70% and <=90%||Semi- Critical|
|3||>90% and <=100%||Critical|
|Net Ground Water Availability for the entire State||5211.75 MCM (ranges from 186.14 MCM in Idukki district to 591.44 MCM in Palakkad district).|
|The Annual Ground Water Extraction for all uses||2672.09 MCM (ranges from 56.78 MCM in Wayanad district to 340.56MCM in Thrissur)|
|The Annual Ground Water Allocation for Domestic use up to 2025||1571.28 MCM (ranges from 38.06 MCM in Wayanad district to 254.99 MCM in Malappuram)|
|The Net Ground Water Availability for future||2408.29 MCM (ranges from 77.48 MCM in Idukki district to 267.10 MCM in Alappuzha district).|
|The Stage of ground water extraction of assessment units||51.27 % for the State (highest in Kasargod district (79.64%) and the lowest in Wayanad district (24.51%).|