The Assessment units have been categorized as “Over-exploited”, “Critical”, “Semicritical” and “Safe” based on Stage of Ground Water Extraction and the long-term decline of average ground water levels in the observation wells in the assessment unit, as per the criteria suggested in GEC-2015 methodology. After that the analysis has to be validated. If in a safe block (SOE≤70%) decadal water level trends are showing falling patterns, then the calculation is unacceptable and re-calculation needs to be made. Again, reassessment is necessary if in an OE block (SOE >100%) long term water level trends in observation wells are showing rising pattern.

                Out of 152 assessed units in the State, 3 blocks (Chittur & Malampuzha blocks of Palakkad district and Kasaragod block of Kasaragod district) have been categorized as “Critical”; 27 blocks are “Semi-critical” and 122 blocks are in “Safe” category. The Stage of Ground Water Extraction and the block-wise long-term (2010- 2021) water level trends of the observation wells being monitored by Central Ground Water Board and the State Ground Water Department for pre and post-monsoon were considered for categorization of the blocks. The spatial distribution of different categories of assessment units is given in Figure below:

Categorization of Blocks in Kerala (As in March 2022)

(Source: Ground Water Resources of Kerala (March 2022), Ground Water Department & Central Ground Water Board)

Groundwater Management

                The National Water Policy of the Government of India states that the non conventional method for utilization of water such as through artificial recharge to ground water and traditional water conservation practices like rainwater harvesting need to be practiced to increase the utilizable water resources. The rainwater harvesting can be effected by in-situ-Harvesting and artificial recharge to ground water is the process of diverting the surface water into suitable geological formation. The common structures are percolation tanks, khadins, check dam/Anicut, sub-surface dams and injection wells. The ground water storage is the best method for water harvesting as it not only involves filtration of surface but is also safe from evaporation losses, natural catastrophes etc. Central Ground Water Board has implemented various artificial recharge schemes in Kerala like surface dykes, percolation tanks, and of top rainwater harvesting. Four sub-suface dams were constructed at Palghat district (Anaganadi, Bhabaji Nagar, Alanallur and Ottappalam), one at Ernakulam (Odakali), one at Kottayam (Neezhir) one at Quilon (Sandanadapuram) and two at Trivandrum district (Mampazhakara and Ayiolam). Central Ground Water Board has constructed two percolation tanks, one at Chirakulam of Kottayam district and another one at Kadapallam of Kasaragod district. Roof top rainwater harvesting schemes were implemented at two places viz. Ezhimala and Mayyilcolony of Kannur district. The artificial recharge structures have given satisfactory results and the groundwater condition in the area has improved considerably.

            Rainwater harvesting is the viable solution in the monsoon rich state of Kerala. The common structures feasible for Kerala are sub-surface dykes, nala bunds, check dams. The traditional water conservation structures like natural ponds, reservoirs should be desilted and cleaned. Participatory watershed development programmes should be implemented in the State. Mass awareness programme on ground water conservation should be arranged at Panchayat level in all districts.

Other Resources:

             Apart from rivers and wells sources like tanks, ponds, springs and surangams are also use in Kerala for providing water for drinking as well as irrigation. It is estimated that Kerala has approximately 995tanks and ponds having more than 15000 Mm³ summer storage. Natural springs occurring in the highland regions of Kerala state have the potential to be developed as good sources for drinking water supply and also for limited small scale irrigation, especially in remote and under developed areas. A total of 236 springs have been identified in the state. Kasaragode district in Northern Kerala has 510 special kind of water harvesting structure called Surangams which have >111pm discharge.

Hydrology Information Systems:
 

                 The State has 41 west-flowing and three east-flowing rivers, and has an average annual rainfall of about 3,000mm. However, the extent to which it can retain, store, and use these for agricultural purposes is still inadequate. In order to have a realistic assessment of water resources in the State, the Investigation Design and Research Board of Irrigation department is in the process of modernising the existing hydrology information system with a Real-Time Data Acquisition System. The core activity of the hydrology wing of the Irrigation department is the collection, validation, and collation of hydro-meteorological data from various gauging stations, established across Kerala river basins. The National Hydrology Project, funded by World Bank, also aims at improving the quality and accessibility of water resources information and to strengthen the capacity of water resources management institutions in the State. The objective is to establish an effective hydrologic database and hydrological information system for effective water resources planning and management.

                   The consecutive floods of 2018 and 2019 necessitated an early flood warning system for the State. Flood Forecasting and Early Warning System (FFEWS) integrated with reservoir operations for Periyar and Chalakudy basins were initiated during the 13^th Five-Year Plan period under the National Hydrology Project. FFEWS acts as an end-to-end system for issuing timely warning against disaster. The accuracy of the forecast depends on the real time hydro-met data received, and the quality of topographical features.

Overview of the 13^th Five-Year Plan

                The 13^th Five-Year Plan focussed on expanding agricultural productivity by expanding area irrigated, and increasing the irrigation potential and efficiency. There was special focus on canal modernisation, drought management, and the completion and commissioning of ongoing major and medium irrigation projects. Though the share of minor irrigation outlay has increased during the Plan period, major and medium irrigation continued to play a dominant role in the sector outlay. The total budgeted outlay for the sector during the 13^th Plan period was ₹2,682.15 crore. Major and Medium irrigation had the largest share (51.79 per cent), followed by minor irrigation (33 per cent), flood control measures (14.46 per cent), and command area development (0.74 per cent).

Irrigation Status: 

                 As per the assessment of Directorate of Economics and Statistics, the net irrigated area in the State in 2021-22 was 4.03 lakh ha, whereas the gross irrigated area was 5.61 lakh ha. There has been an increase in the net and gross irrigated area in 2021-22, compared to the previous year. The percentage of gross irrigated area to gross cropped area increased from 20.30 per cent in 2020-21 to 22.25 per cent in 21-22, which is significant. The gross irrigated area shows a consistent increase from 5.17 lakh ha in 2019-20 to 5.21 lakh ha in 2020-21, and further to 5.61 lakh ha in 2021-22. Source-wise, the net area irrigated through wells leads with 1.66 lakh ha, followed by other sources (1.16 lakh ha), and small streams (thodu) (0.72 lakh ha) in 2021-22. Details on the source-wise and District-wise net area irrigated are given below:

District - Wise Net Area Irrigated (Source Wise) 2021 - 22 are given here.

              Crop-wise, paddy and coconut are the major crops most benefitted though irrigation. However, the extent of gross irrigated area under paddy and coconut shows a decline in 2021-22 compared to the previous year. The gross area irrigated under paddy declined to 1.54 lakh ha in 2021-22 from 1.59 lakh ha in 2020-21 and that of coconut declined to 1.52 lakh ha from 1.58 lakh ha during the corresponding period. Percentage of irrigated area under paddy to total irrigated area has fallen to 27.44, as against 30.61 per cent in 2020-21. A sharp fall is seen in the gross area irrigated of banana. In 2020-21, the gross area irrigated under banana was 0.52 lakh ha, which reduced to 0.37 lakh ha in 2021-22. A similar declining trend is seen in the irrigated area of vegetables, marking a fall from 0.28 lakh ha in 2020-21 to 0.25 lakh ha in 2021-22. Details on gross area irrigated and crops benefitted are given here.

Highlights of the Department during the 13^th Five-Year Plan Period

Thrust on Major and Medium Irrigation Projects

                    The Government decided to examine the works of four major and medium irrigation projects-Muvattupuzha, Idamalayar, Karapuzha, and Banasura Sagar. These projects have been under implementation over several decades. The Kerala State Planning Board constituted a five-member Technical Committee in the first year of the 13th Plan period to evaluate these irrigation projects. After understanding the hurdles in implementation, the Committee defined certain targets and timelines for the completion/commissioning of these projects, and they were funded accordingly during the Plan period.

                   The commissioning of Muvattupuzha valley irrigation project in July 2020 was a notable achievement during the period. With a cumulative expenditure of ₹1,083.64 crore, as on date of commissioning, the project benefitted ayacuts of 33,670 (ha) (gross) and 17,179 ha (net). The hindrance in the MC road crossing in the Low-Level Canal of Idamalayar Irrigation project was cleared by adopting the push-through mechanism, the first of its kind in the Department. Thus, the water distribution through this stretch of Low-Level Canal helped meet the agricultural and drinking water requirements of Nedumbassery Panchayat and Angamaly Municipality. For the construction work in the railway crossing portion of the Low-Level Canal, ₹3.06 crore was deposited to the railway authorities.

                 In the Karapuzha project, the breach rectification works carried out in the Left Bank Main Canal (LBMC) and Right Bank Main Canal (RBMC), would enable water distribution through the entire main canals for the total length of 25.54km from 2022 onwards, which would benefit an ayacut of 636.48 ha. Thus, main canals could be made operational for the first time since the inception of the project. The Karapuzha mega tourism project in the dam premises, inaugurated in 2017, also contributed to the development of the region. The rectification works in the main canal of Banasurasagar project have begun for clearing the major bottleneck from Ch.1130m to 1,500m. Land acquisition processes for Venniyode and Kappumkunnu distributories were also initiated during the period.

Dam Rehabilitation and Improvement Project (DRIP): The Dam Rehabilitation and Improvement Project (DRIP) aims at improving the safety and operational performance of sixteen dams/barrages/regulators of Irrigation department with the financial assistance from World Bank. Phase I of the project, initiated in 2012, got extended up to March 2021. Major achievements of DRIP Phase I are- (1) Rehabilitation works of 13 dams, including civil, mechanical and electrical works (2) Renovation works of Moolathara regulator (3) Hydro mechanical renovation works of 14 dams (4) Strengthening works of eight dams – Chimoni, Kallada, Kanjirapuzha, Kuttiyadi, Malmapuzha, Malankara, Pazhassi and Pothundy (5) Approval of Emergency Action Plan of 14 dams by CWC (6) Web-based software package to support the effective collection and management of dam safety data. Kerala Water Resources Department is now part of DRIP Phase-II (2021-2027) for improving the safety and operational performance of 15 dams/barrages/regulator of Irrigation department.

Improved focus on Minor Irrigation:  Greater efficiency in irrigation could be achieved through proper designing of irrigation systems for reducing water conveyance loss. Minor irrigation schemes are intended for irrigating smaller command areas by way of diversion of water from rivers and canals and by effecting proper drainage by constructing sidewalls, sluices and crossbars. The minor irrigation census provides a comprehensive data base on the irrigation potential created and utilised, water distribution practices, and sources used for energising the schemes. Efforts are needed for the efficient management of water resources in a sustainable manner. Micro-irrigation can play a vital role in improving the water use efficiency. As on March 31, 2021, the area covered under micro irrigation in Kerala (Drip and Sprinkler) was 33,264 ha.

(Source: Ministry of Agriculture and Farmer’s Welfare Department; Indiastat).

                    Adoption of water-saving technologies like sprinkler and drip irrigation systems have proven to be efficient not just in water conservation, but also in increasing the yield. As part of promoting the same, the Irrigation department has initiated the implementation of community micro-irrigation projects across the State with the assistance of other stakeholder Departments. Based on the joint inspection by the Departments of Agriculture and Irrigation, twenty-one project sites were identified. Among these, six projects identified in the districts of Pathanamthitta, Idukki, Wayanad and Thrissur are taken up in the first phase, and are in design and implementation stages.

Minor Irrigation Schemes During the 13^th Five-Year Plan Period: One of the major objectives during the 13^th Five-Year Plan period was the shift of focus from major and medium irrigation to minor irrigation. Physical achievements of minor irrigation (surface water) during the period 2017-18  to 2021-22 are given below:

Physical achievement of Minor Irrigation, 2017-18 to 2021-22 (in ha)