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| Last Updated:: 17/07/2022

Water

 

         From the point of view of water resources Kerala is having both abundance and scarecity. The average annual rainfall of the state is 3000mm, the bulk of which (70%) is received during the South-West monsoon which sets in by June and extends upto September. The state also get rains from the North-East monsoon during October to December.However the spatial and temporal distribution pattern is mainly responsible for the frequent floods and droughts in Kerala. The average annual rainfall in the lowland of Kerala ranges from 900mm in the south to 3500mm in the north. In the midland, annual rainfall ranges from 1400mm in the south to about 6000mm in the north. In the highland, annual rainfall varies from 2500mm in the south to about 6000mm in the north. Kerala has got 41 west-flowing and 3 east-flowing were originating from the Western Ghats. The total annual yield of all these rivers together is 78.041 Million Cubic Meters (MCM) of which 70,323 MCM is in Kerala. The peculiarity of the rivers flowing across Kerala is short length of the river and the elevational difference between the high and the low land leading to quick flow of water collected from the river basin and quickly discharged into the Lakshsdweep sea, the state has not been able to utilise the river water sources to a major extent. The major portion of the runoff through the rivers takes place during the monsoon seasons. 67.29% of the surface water area of 3.61 lakh hectares is constituted by brackish water lakes, backwaters and estuaries.

 

        On a rough estimate, the source wise dependence by rural households for domestic water supply dependent on traditional ground water systems is 80%, 10-15% use piped water supply systems, and 5% use traditional-surface and other systems.

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  Fresh water availability in Kerala is given here

 

A graphical distribution of the locations of water on Earth

 

 


Surface Water Resources:

 

              Kerala is rich with 44 rivers which together yield 70300Mm³of water annually. However the total utilizable yield is estimated to be 42000Mm³, only 60% of the annual yield. Kerala possess only four medium rivers and 40 minor rivers.

 

                In the all India perspective the rivers of kerala are not so significant than even the largest of them cannot find a place among the major Indian rivers. With respect to the national norm Kerala does not have a single major river and has only four medium rivers. The combined discharge of these four rivers is less than half of that of river Krishna. The remaining fourty rivers are only minor ones, the combined discharge of all of them together is only about one-third of that of Godavari. western ghats from where the river originate is devoid of snow and therefore these river systems do not have the benefit of water supplied during the summer seasons as in the north Indian rivers.


Ground water Resource of Kerala:

 

            Kerala is a tiny strip of land, located in the south-western tip of India between North latitudes 80 18’and 120 48’ and East longitudes 740 52’ and 770 22’, occupying only 1.2 percent of India's land area. Its geographical contours can be described as an elongated strip of land, cushioned between the Western Ghats on the east and the sandy shores of the Arabian Sea on the west. Its land area is 38,863 Sq. Km, stretching 580 Km in length and 30.130 Km in average breadth. In terms of area, though Kerala forms only 1.2% of the total area of India (3,287,263 Sq. Km), 3 percent of country's population inhabits the State. The State is subdivided into 14 districts and 152 blocks for administrative convenience.

 

              The occurrence and availability of ground water vary considerably from place to place within the State depending on the prevailing climatic, geomorphological and hydrogeological conditions. About 88 percent of the total geographical area of the State is underlain by crystalline rocks devoid of any primary porosity, with limited ground water prospects. In the alluvial formations having multiple aquifer systems, quality is sometimes a constraint in the optimal development of available resources. Increasing population, rapid urbanization and industrialization has resulted in increasing use of ground water resources over the last few decades in the State. Judicious and planned development of ground water and its scientific management have become necessary to ensure long-term sustainability of this precious natural resource in Kerala. The dynamic ground water resources of the State are being periodically assessed by the Central Ground Water Board (CGWB), jointly with the State Ground Water Department and other Central Government as well as State Government agencies, according to the methodology recommended by the Groundwater Estimation Committee constituted by Govt. of India from time to time.

 

                  Groundwater has been the mainstay for meeting the domestic needs of more than 80% of rural and 50% of urban population besides, fulfilling the irrigation needs of around 50% of irrigated agriculture. The ease and simplicity of its extraction has played an important role in its development. Recent the problems of decline in water table, contamination of groundwater, seawater intrusion etc. are being reported at many places. 

 

Hydrogeology:

 

          Kerala State is a narrow stretch of land covering 38863 sq.km area bordering the Lakshadweep Sea on the western side and Tamil Nadu Karnataka Station the eastern side. The length of the State from north to south is 560km and the average width is 70km with a maximum of 125km. it lies between North latitudes 08 0 18' and 12 0 48' and east longitudes 74 0 52' and 77 0 22'.

 

The occurrence and movement of groundwater in various litho-units underlying the State are mainly controlled by the physiography, geological setting and structural features.

 

(i) Physiography:

              Physiographically the State is divided into three major units viz. the coastal plains, the midlands and the hill ranges. The coastal plains have an elevation of less than 7.6m whereas the elevation of the midland ranges from 7.6 to 76 m and that of the hill ranges is more than 76 m above mean sea level (amsl). Along the hill ranges two distinct plateau regions are seen, the important being the Wayanad plateau, which covers major part of Wayanad district, the general elevation of which is above 700 m amsl. The other plateau is the Munnar plateau in Idukki district, the elevation of which is about 1000 m amsl.

 

(ii) Rain Fall: 

                Kerala receives normal annual rainfall of 3060 mm, received mainly during the Southwest Monsoon period, extending from May to September, followed by the Northeast Monsoon in the months of November and December. The period between May and October accounts for about 87 percent of the annual rainfall. This period has been considered as monsoon season for computation of monsoon rainfall recharge. The amount of rainfall received shows a gradual decrease from North to South.

 

(iii) Geology:

                As much as 88% of the State is underlain by crystalline rocks of Archaean age comprising schistose formations, Charnockites, Khondalites and gneisses. All these formations are intruded by dykes of younger age. The sedimentary formations of Tertiary age occurring along the western parts of the State comprise four distinct beds viz. Alleppey, Vaikom, Quilon and Warkali. The crystalline and the Tertiary formations are lateritized along the midland area. Alluvial deposits of Recent origin are seen along the coastal plains.

Occurrence of Groundwater:

 

             Ground water occurs under phreatic, semi-confined and confined conditions in the above formations. The weathers crystallines, laterites and the alluvial formations from the major phreatic aquifers, whereas the deep fractures in the crystallines and the granular zones in the Tertiary sedimentary formations form the semi-confined and confined aquifers.Along the hill ranges, the crystalline rocks are covered by thin weathered zone. Thick zones of weathered crystallines are seen along midland region. The depth to water level in the weathered crystallines in the midland area ranges from 3 to 16mbgl. The midland area sustains medium capacity dug wells for irrigation. Mostly dug wells that can cater to domestic needs are feasible along topographic lows. Bore wells tapping deeper fractured aquifer are feasible along potential fractures in the midland and hill ranges. Potential fractures are seen down to 240m and the most productive zone is between 60 and 175m and the discharge of bore wells range between 36,000 and 1,25,000 lph.

 

          Of the four Tertiary beds, the two beds viz. the Vaikom and Warkali beds are potential aquifers. The Alleppey beds at the bottom contains bhrackish water as inferred from electrical logs, whereas, the Quilon beds are poor aquifers. The Vaikom aquifer is seen all along the coast between Quilon and Ponnani and the piezometric surface ranges from 1 to 18 m above msl. The aquifer is extensively developed between Quilon and Kayamkulam. The aquifer contains fresh water south of Karuvatta in Alleppey district and also north of chellanum in Ernakumal district. The Warkalai aquifer is seen south of Cochin . The piezometric head in the aquifer varies from 2.6m above msl to 10m above msl. The aquifer is largely developed in and around Alleppey and in Kuttanad area.

 

              Laterites are the most widely distributed lithological unit in the State and the thickness of this formation varies from a few meters to about 30m. The depth to water level in the formation ranges from less than a meter to 25 mbgl. Laterite forms potential aquifers along valleys and can sustain medium duty irrigation wells with the yields in the range of 0.5-6m3 per day.

 

             The alluvium forms potential aquifer along the coastal plains and ground water occurs under phreatic and semi-confined conditions in this aquifer. The thickness of this formation varies from few meters to above 100m and the depth to water level ranges from less than a meter to 6m bgl. Filter point wells are feasible wherever the saturated thickness exceeds 5m.               


Ground water potential of Kerala:

 

             The ground water potential of Kerala is very low as compared to that of many other states in the country. The estimated ground water balance is 5590Mm³. Dug wells are the major ground water extraction structure in Kerala. The dug wells have a maximum depth of about 10 to 15 meters and have a diameter of about 1 to 2 meters in coastal region and 2 to 6 meters in the midland and high land. The open well density in Kerala is perhaps the highest in the country-200 wells per sq.km in the coastal region, 150 wells per sq.km in the midland and 70 wells per sq.km in the high land. The ground water withdrawal is estimated as 980Mm³ and the State Ground Water Department calculate the effective recharge as 8134 sq Mm³.The ground water level receding drastically during the summer months and drying up of wells are common features of the ground water levels in many parts of Kerala. The ground water replenishment and hence the levels depends also on the geo-morphological, physical and chemical properties of the soil in general, The depth of water level in Kerala state varies from few cm bgl to 56 M bgl and most of the area fall under 0-20 M bgl. The depth of the water level in the weathered crystalline of midland areas in Kerala varies from 3- 16 M bgl. The midland area sustains medium capacity dugwells.

 

           Borewells tapping deeper fractured aquifer are feasible along potential features in the midland and hill ranges. Potential fractures are seen down to 240 M and the most productive zone is between 60 M and 175 M. The discharge of borewells range between 3,600 Iph and 1,25,000 Iph. In laterites, which is the most widely distributed lithological area in the state having a thickness from a 3 M to 30 M, the depth of water level ranges from less than a meter to 25 M.bgl. Lateries from potential aquifer along valleys and can sustain wells with yields in the range of 0.5 M³ to 6 M³ per day. Along the coastal plains the ground water occurs at depth ranging from less than a meter to 6 M.bgl. Filter point wells are feasible wherever the saturated availability indicate that ground water depths are farthest for laterite regions and shallowest for coastal alluvium during all times of the year. The availability of the groundwater level between the post and ore monsoon levels varies widely. The water level fluctuations in the post monsoon and ore monsoon vary between coastal alluvium, river alluvium and valley hills.


Groundwater Availiability of Kerala:

 

               Ground water fulfils the irrigation needs of around 50 percent of irrigated area. The total Annual ground water availability in Kerala State has been computed as 6.620 Billion Cubic Meter (BCM) and the net ground water availability in the entire state is 6.029 BCM. The rainfall recharge accounts for about 82 percent of the annual recharge. The annual ground water draft for all uses in the state is 2.809BCM. The net Ground water availability for future irrigation development in the state as in 2009 is of the order of 3.021 BCM. The overall stage of development of the State is 47 percent. The district wise stage of development is maximum in Kasaragod (71 percent) and minimum in Wayanad district (17 percent). Details are given here  The net annual ground water availability for the state of Kerala during 2009 has reduced to 3.22 per cent compared with the data during 2004. The annual ground water draft for all uses has reduced by 3.80 per cent during the period. The net ground water availability for future irrigation development in the state as a whole shows a decline of 1.74 per cent in 2009 compared to 2004.

 

                As per 2011 census, 65 percent of rural and 59 percent of urban households have wells. The ground water potential of Kerala is limited because 88 percent of the total geographical area of the State is underlain by crystalline rocks devoid of any porosity. There are 10 different principal aquifer systems in Kerala. Groundwater in Kerala has a potential of 34-601 metres below ground level (mbgl) and the yield varies between 0.1 – 38 lps (litres per second) depending on the area.

 

                 As per ground water resource data 2011, the total annual ground water availability and the net groundwater availability in the State is 6.69 Billion Cubic Meter (BCM) and 6.07 BCM respectively. The annual ground water draft for all uses in the State is 2.84 BCM out of which 1.31 BCM is for irrigation purpose. 3.07 BCM is the net ground water availability for future irrigation development in the State. The stage of ground water development of our State is 47%. Among the districts, Kasaragod and Wayanad ranks maximum and minimum with 71% and 18% respectively. Out of the 152 revenue blocks assessed in the State during 2011 for groundwater potential, 1 block (Chittur) is categorized as over exploited, 2 blocks (Kasaragod, Malampuzha) as critical, 23 blocks as semi- critical and 126 blocks as safe. The details of Ground Water Resources of Kerala during 2011 is given here.

 

             As per ground water resource data 2013 assessment, total Annual Ground Water Availability in Kerala State as on March 31, 2013 has been computed as 5.664 Billion Cubic Metre (BCM). Rainfall recharge accounts for about 82 percent of the annual recharge, with the remainder contributed by other sources. The contribution of districts to the total annual recharge of the State is shown below: Contribution of districts to the Total Annual Ground Water Recharge in Kerala is given here.
 

 

              As per the assessment 2013, the Net Ground Water Availability for the entire State is 5.664 billion cubic metre (BCM). The district-wise availability in the State ranges from 200.43MCM in Idukki district to 637.83MCM in Palakkad district. The Annual Ground Water Draft for all uses in the State is of the order of 2.635 BCM and ranges from 54.74 MCM in Wayanad district to 352.85 MCM in Palakkad district. Details of block- wise groundwater draft are given in Annexure IIID. The spatial distribution of ground water draft among districts in the State is given  here. 

 

            The Net Ground Water Availability for future irrigation development in the State as in March 2013 is of the order of 2.94 BCM. The district-wise net ground water availability ranges from 98.65 MCM in Kasargod district to 325.33 MCM in Ernakulam district. District-wise status of Net Ground Water Availability and Annual Ground Water Draft for all uses is shown here. Table 1, Table 2.  

 

              As per the data on Dynamic Ground Water Resources of Kerala (2013), total annual ground water recharge of the State is 6,251.31 MCM and the net annual ground water availability is 5,651.53 MCM. The existing Gross Ground water draft for Irrigation is 1,181.77 MCM and the existing gross ground water draft for all uses is 2,634.91 MCM. The net ground water availability for future irrigation development is 2,944.62 MCM. The stage of ground water development of our State is 46.62 percent. Kasaragod leads with 69.81 per cent followed by Thiruvananthapuram with 60.27 percent. The stage of ground water development is least for Wayanad District (19.48 per cent). Details are given here.

 

           Major schemes implemented by the department are Investigation and Development of Ground Water Resources and scheme for ground water conservation and artificial recharge. In 2017-18, ground water investigation was done for 2,585 dug wells and 10,183 drilled wells. The financial achievement of the scheme is 70 per cent. With the objective of preventing adverse environmental impacts of over exploitation of ground water and to ensure equitable distribution of resources to all, ground water control and regulation is being enforced. In 2017-18, 759 permits were issued and 25 numbers of NOC were issued for groundwater extraction for packaged drinking water units.

 

                 The Groundwater estimation in the State is being done jointly by State Groundwater Department and Central Ground water Board. Under the scheme Investigation and development of Ground water resources, in 2018-19, investigation was carried out for 1884 dug wells and 9088 drilled wells. Ground water department prevents the over exploitation of ground water and ensures equitable distribution of resources. 1171 permits were issued in 2018-19. As per the data on Dynamic Ground Water Resources of Kerala (2017), the total annual Ground water recharge of the State is 5769.23 MCM and the net annual Ground water availability is 5211.75 MCM. The existing gross Ground water draft for irrigation is 1220.57 MCM and the existing ground water draft for all uses is 2652.77 MCM. The stage of Ground water development of our State is 51.27 per cent. Kasaragod continues to lead the list with 79.64 per cent. The stage of Ground water development is least for Wayanad District with 24.51 per cent. Details are given here.

 

                 Sustainable development of groundwater resources require scientific ground water conservation and recharge systems. These recharge schemes are being implemented as a long term measure to overcome the drought situation in the State. The project components include roof top rain water harvesting for ground water recharge through dug wells, recharge pits, bore wells, subsurface dykes and small check dams. Ground water recharge through roof top rain water harvesting is done in public buildings and government schools. Details on the total annual ground water recharge, net annual ground water availability and stages of ground water development in our State is given here.

 

Major and Medium Irrigation Projects 

 

     There are 54 dams in the State. Out of this, 14 dams and 6 barrages are maintained by the Irrigation Department. The live storage of reservoirs under Irrigation Department in the State is estimated as 1431 Mm3. The live storage position of the reservoirs at the beginning and end of the monsoon during the period 2016 to 2018 is given here.

 

                  In 2018, at the beginning of the monsoon (01/06/2018), the total storage was 642.57 Mm3 and at the end of the monsoon October 1, 2018, the level was raised to 1285.73 Mm3, as against the previous year levels of 266.24 Mm3 and 1,111.31 Mm3 respectively. Compared to 2017, the year 2018 is a wet year and hence there is an increase in storage in most of the dams.

 

                   The 4 ongoing projects viz., Muvattupuzha, Idamalayar, Karapuzha and Banasurasagar that commenced in 1970s and 1980s, but still continuing with consequent time and cost over runs. The unprecedented delay in implementation is the result of administrative and technical factors.  

 

                 Irrigation schemes with ayacut area greater than 10,000 ha are classified as Major Irrigation schemes and those schemes which serve ayacut area between 2,000 ha to 10,000 ha come under Medium Irrigation. The four on-going major irrigation projects in Kerala - Muvattupuzha, Idamalayar, Karapuzha and Banasurasagar – were started in the 1970s and 1980s. However, their construction is still continuing with time and cost overruns. The status of implementation of the four Major and Medium irrigation projects is given below: 

 

 

Status of implementation of the four major and medium irrigation projects in Kerala

Name of Project

Districts Covered

Year of Commencement

Targeted Gross area

(in ha)

Muvattupuzha Valley irrigation project

Ernakulum, Idukki

1974

35619

Idamalayar irrigation Project

Ernakulam, Idukki, Thrissur

1981

29036

Karapuzha Irrigation Project

Wayanad

1978

8721

Banasurasagar Irrigation Project

Wayanad

1979

3825

Source: Technical committee report on major and medium irrigation projects, KSPB

 


Details of ongoing Major and Medium Irrigation Projects in Kerala is given here.

 

 

 Categorization of Blocks

 

                 As per 2013 reports, the assessment units have been categorized as “Over-exploited”, “Critical”, “Semi-critical” or “Safe” on the basis of Stage of Ground Water Development and the long-term decline of average ground water levels in the observations wells in the assessment unit, as per the criteria suggested in GEC-1997 methodology. Decline of ground water levels of 15 cm per year or more has been considered significant in the State while categorizing the blocks. However, in such units where the monsoon recharge has been computed by ad-hoc method on account of the water level data not being representative, categorization has been done primarily on the basis of stage of development and the existing ground situation. Out of 152 assessed units in the State, Chittur block of Palakkad district has been categorized as ‘Over-exploited’ and 2 blocks (Kasargod block of Kasargod district and Malampuzha block of Palakkad district) have been categorized as “Critical”. Out of the remaining blocks, 18blocks are “Semi-critical” and 131 blocks are “Safe”.

 

 • 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 hydro geological 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

1

<=70%

Safe

2

>70% and <=90%

Semi- Critical

3

>90% and <=100%

Critical

4

>100%

Over Exploited

 

 

Stages of Groundwater Development  |  Categorisation of blocks Kerala as on march 2013

 

 

 

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%).

 

 

Depth to Water Levels

 

                 The depth to water level was monitored from 1006 monitoring wells distributed throughout the State during the months of April, August, November and January. The water level measured during the month of April is taken as pre-monsoon water level and the data of November is taken as post-monsoon water level, on the basis of temporal distribution of long-term rainfall in the State. The depth to water level mostly depends on the hydrogeological conditions of the area as well as topography, rainfall pattern, etc. In coastal plains the depth to water level is generally restricted to 6 mbgl. In midland areas, where the undulating topography is seen, the depth to water level generally varies from near ground level to 25 mbgl. The variation is mostly due to topographical variations, thickness of lateritic overburden etc. In areas where laterites are underlain by sedimentary aquifers of Tertiary age, the water level goes very deep, even to the extent of 55 mbgl. In highlands the depth to water level is in the range of few cm to 10 mbgl depending on the topography and thickness of overburden (weathered zone).

 

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.


Major Irrigation Projects and Irrigation Status of Kerala 

 

Karapuzha Irrigation Project:

 

                 Karapuzha Irrigation Project (KIP) is the first medium irrigation project in the Kabini Sub Basin of Cauvery river. Cauvery Water Disputes Tribunal (CWDT) has awarded 2.80 TMC of Cauvery water to Karapuzha. Karapuzha Irrigation Project is one of the 99 prioritised projects under Accelerated Irrigation Benefit Programme (AIBP). This project consists of an earthen dam with concrete spillway across Karapuzha river at Vazhavatta in Vythiri Taluk of Wayanad District for providing irrigation to a net ayacut of 5221 ha Cultivable Command Area (CCA) in Vythiri, Sulthanbathery and Mananthavady taluks of Wayanad District. Reservoir has a gross storage capacity of 76.50 Million Cubic Meter (MCM) with live storage capacity of 72.00 MCM.

 

                 This project was approved by Planning Commission in 1978 and administrative sanction was issued for ₹7.60 crore envisaging irrigation to Cultivable Command Area of 5,600 ha with ultimate irrigation potential of 8,721 ha. Karapuzha Irrigation Project was partially commissioned on 20th June 2010. Rectification of two main bottle necks were completed – (1) Rectification of breach in RB main canal at Edakkaravayal Ch. 7673 m-7888 m completed and is ready for water distribution from 2018 onwards (2) Rock portion in Padinjaraveedu branch canal near Ch. 330 m which off takes from the tail end of Left bank Main canal also cleared and connection made between the existing canal on both sides. From March 2017 onwards, water distribution through Left Bank Main Canal is carried out up to 15.30 km in trial basis. 1st phase of tourism project in Karapuzha was completed and the park and garden were opened to the public in June 2017. The present cost of the project is ₹560 crore (as per DSR 2014). The expenditure incurred up to August 31, 2018 is ₹322.69 crore. The total CCA created is 601 ha and the corresponding irrigation potential is 938 ha.  

 

                 Karapuzha Irrigation Project, a medium irrigation project in Kabini sub basin of Cauvery river, was awarded 2.80 TMC of Cauvery water. The project was approved by Planning Commission in 1978 for ₹7.60 crore and was partially commissioned on June 20, 2010. The project has a Right Bank Main Canal (RBMC) with a length of 8,805 m and Left Bank Canal (LBMC) with a length of 16,740 m.

 

Achievements during 13th FYP:

 

                 A major setback to the Karapuzha Irrigation Project occurred due to Canal breach during floods in 2018 at Ch: 4,800m of Left Bank Main Canal reducing the ayacut area of LBMC from 245.17ha to 71.29ha. The rectification work of this major breach at Ch: 4,800 m is in progress and is proposed to be completed by November 2021. After completing these works the entire LBMC up to tail end ie; up to Ch: 16,740 m can be made functional for irrigating a total ayacut of 245.17 ha. During the floods in 2019, Canal Breach occurred at Ch:1,800 m of Kariambady Branch Canal which off takes from the tail end of the Right Bank Main Canal. The design of the structure has to be revised as this breached Canal was passing over an embankment of about 8m height and soil exploration work has been arranged in this reach. Land required for the construction of Ponginithody, Arimula, Vallipetta, Cheekkallura and Manivayal distributaries off-taking from the Right Bank Canal system are in the possession of the department and works in these reaches are proposed in 2021-22. This will provide irrigation to an additional ayacut of 459ha.

 

Muvattupuzha Valley Irrigation Project (MVIP):

 

              The Muvattupuzha Valley Irrigation Project (MVIP), one of the major projects in Kerala envisages the utilisation of the tailrace discharge2 from the Moolamattom power House of the Idukki Hydro-Electric Project and the dependable runoff from the catchments of Thodupuzha river. MVIP was started in 1974 with an estimated cost of ₹20.86 crore and was approved by the Planning Commission in June 1983 at an estimated cost of ₹48.08 crore. The project was partially commissioned in 1994. Out of the total ayacut of 35,619 ha, an ayacut of 32,627 ha was created up to August 2018. 100 per cent works of main canal and branches and 90 per cent works of distributaries have been completed. Two works viz., construction of Ezhuthonipadam aqueduct over railway portion and Manjoor distributary pipeline crossing in railway portion has been completed this year. Water distribution will be commenced this year itself, and an ayacut of 1,335 ha can be utilised for irrigation. The estimated cost of the project based on 2015 Delhi Schedule of Rate (DSR) is ₹945.00 crore and the expenditure up to August 31, 2018 is ₹970.58 crore.

 

                 The Muvattupuzha Valley irrigation project envisages the utilisation of tailrace discharge from Moolamattom powerhouse of the Idukki hydroelectric project and the dependable runoff from the catchments of Thodupuzha river. Muvattupuzha Valley Irrigation project was commissioned on July 10, 2020 by completing the works of Main Canal, Branch Canals and Distributories except Edayar distributory and few reaches of Karikode Distributory. This Irrigation Project, started with an initial estimate cost of ₹20.86 crore, has Right Bank Main Canal (RBMC-28.339 km) and Left Bank Main Canal (LBMC-37.1 km). The branches of RBMC and LBMC have a total length of 57.154 km, while the distributaries have a total length of 213 km.

 

Progress of the project during the 13th Five Year Plan Period

 

• Completion of aqueduct at the railway crossing portion in Ezhuthonippadam, (between Ch.18,238m and 18,261m) created 796 ha, out of which 11ha was benefitted through Ettumanoor branch canal and 785 ha through Kurumulloor distributary

 

• Anicad East (Nadukkara) minor distributary (1620 m) length was completed and an ayacut of 196 Ha achieved during this year.

 

• With the completion of Madakkathanam Minor Distributary Painkulam aqueduct, an ayacut of 561 Ha was achieved during this year.

 

• With the completion of the lift of Koothattukulam distributary 450ha has been achieved during 2020-21. Koothattukulam lift was completed on May 28, 2020 and achieved an ayacut of 1,080 ha.Karikode 1st reach (0-1210m) provided an ayacut of 250ha.

 

• The envisaged ayacut of MVIP was 35,619ha (Gross) and 18,173ha (Net). As on date of commissioning, the total ayacut achieved from this project is 33,905 ha (Gross) and 17,342ha (Net). The cumulative expenditure incurred for the project as on March 31, 2021 is ₹1,100.88 crore.

 

Project Benefits: Main crops irrigated include paddy (3,364 ha), banana (2,126 ha), pulses (930 ha), tapioca (448 ha), ginger (14 ha), pineapple (790 ha), coconut (6,354 ha), arecanut (548 ha), rubber (3,868 ha), pepper (281 ha), vegetable (1,765 ha), coffee (16 ha), nutmeg (78 ha), turmeric (35 ha), cocoa (40 ha), miscellaneous trees (380 ha) and tubers (520 ha). This project also helps in desalination of low level paddy fields in Kottayam district and benefits the drinking water supply schemes of Idukki, Ernakulam and Kottayam districts. It helps in enhancing the ground water levels of nearby wells. Hindustan News Print Factory is one the beneficiary of the project. It also helps in the generation of hydel power of 10.5 MW.

 

Idamalayar Irrigation Project (IIP):

 

               Idamalayar irrigation project (IIP) is a scheme for diverting water of Periyar river for irrigating 14,394 ha of cultivable lands in Periyar and Chalakudy basins. The work commenced in 1981 at an estimated cost of ₹17.85 crore. Main components of the project are – (1) A head regulator across the main canal at its starting point. (2) Canal system consisting of – Main canal (32.278 km), low level canal (27.25 km), and link canal (7.575 km).

 

                 Main Canal for a full length of 32.278 km had been completed. Works of low level canal is completed up to 15th km except at MC road crossing (Ch. 10,490 m to 10,599 m) and Railway crossing (Ch. 13,818.5 m to 13,879.50 m). After completing these two works, water distribution is possible upto 15th km of Low level canal which will benefit the agricultural and drinking water need of Angamaly Municipality and Nedumbassery Panchayat. Construction works of link canal is completed from Ch. 445 m to 608 m. The total ayacut achieved is 3,048 ha and the expenditure up to August 31, 2018 is ₹350.83 crore.

 

                Idamalayar irrigation project, which commenced in 1981 with an estimated cost of ₹17.85 crore, aims at irrigating 14,394 ha of cultivable lands in Periyar and Chalakudy basins. Main canal works were completed for the full length of 32.278 km. The length of the Low level Canal is limited to 15 kilometers, wherein there were two bottlenecks – MC road crossing and railway crossing.

 

Some of the notable achievements of the project during the 13th FYP

 

• In 2020-21, Push Through construction was carried out for clearing the bottleneck at the MC road crossing portion in the Low Level Canal, the first of its kind in the history of Irrigation Department. This helped in augmenting drinking water and providing agricultural benefits to Nedumbassery panchayat. An additional ayacut of 1,035 ha was achieved subsequent to the push through construction.

 

• 99.5 per cent of Low Level Canal (LLC) has been completed. The construction of balance 74 m of the proposed low level canal includes a railway crossing work. Completion of MC road crossing and the above said stretch of the canal facilitated water distribution upto Ch.12540m, thereby meeting the drinking water and agriculture needs of Nedumbassery Panchayat.

 

• The land acquisition process for the Kanjoor Thekkumbhagom branch canal is in progress. SIA study for 1.333 KM has been completed.

 

• The construction of flush escape at the tail end of Low Level Canal at Ch14,623 is pending due to delay in land acquisition.

 

• DPR for inter basin transfer of water from Periyar basin to Chalakkudy basin by means of link canal has been submitted to Government.

 

• An ayacut of 128 Ha and 396 Ha has been achieved from Manappatuchira and from completion of link canal respectively

 

• The financial expenditure upto March 2021 is ₹507.99 crore and the gross physical achievement is 4,195 Ha.

 

Banasurasagar Irrigation Project:

 

               Banasurasagar Irrigation Project is the second irrigation project in Wayanad District. This Irrigation Project is in the Karamanthodu basin which is a tributary of Panamaram river. The project commenced in 1979 to irrigate an area of 2,800 ha (net) agriculture land for the second and third crops in two taluks of Wayanad District.

 

            The main canal is 2.73 km long and there are two branch canals – Padinjarathara branch canal having a length 9.030 km and Venniyode branch canal with a length of 5.390 km. Of the total main canal, 2,360 m canal works were completed. Works of both branch canals – Padinjarathara and Venniyode are in progress. The revised estimate of the project as per 2016 DSR is ₹165.98 crore and the total expenditure up to August 31, 2018 is ₹59. 18 crore. Table 1, Table 2. 

 


             The overall performance of the major and medium irrigation sector during the initial years was not encouraging.  The cumulative area brought under irrigation through major and medium irrigation projects is 29346 hectares (gross).  The details of the progress of implementation of ongoing projects as on March 2010 are given here. 


                 Banasurasagar Irrigation project, in the Karamanthodu basin, envisages to irrigate an area of 2,800ha (net) agriculture land for the second and third crops in two taluks of Wayanad district. It consists of a main canal having a length of 2.73km and two branch canals - Padinjarathara (9.030km) and Venniyode (5.390km).

 

Achievements in the 13th Five Year Plan

 

• Diversion Chamber completed between Padinjarathara and Venniyode branch Canal

 

• 15 per cent of the work of Venniyode Branch Canal (Ch:20m to Ch:570m) completed and 35 per cent of Ch:4,325m to Ch:4,620m work completed.

 

• Kappumkunnu distributary Ch:3,005m to Ch:3,205m work completed.

 

• Venniyode Branch Canal Ch: 570m to 1715 m work is under progress. 18 per cent of the work completed.

 

• Kappumkunnu distributary Ch:1,480m to 1,565m work is under progress. 40 per cent of the work completed.

 

• In 2019-20 Re investigation of distributaries, reformation of inspection road near diversion chamber works were completed.

 

• 95 per cent of the Investigation works of distributaries completed

 

Flood Management Programmes in Kuttanad: Major flood management works in Kuttanad include strengthening and raising the outer bunds of padasekharams and allied works such as construction of motor thara, shed, sluice, and pipe and box culvert. Notable achievements could be attained in flood control activities through Government of India approved schemes KEL I, KEL II, KEL III and KEL IV thereby protecting 574.83ha, 3,262.91ha, 2,818ha and 5,834ha respectively.

 

Achievements in the 13th Five Year Plan

 

1. Flood Management Programme (FMP) - Mitigation of flood in Kuttanad region-Phase-1 (Group 2-5, 7-8,10-19), 231 padasekharams in kottayam, Alappuzha Districts. The scheme includes flood management works of 231 padasekharams in Kottayam and Alappuzha districts. By completing the outer bunds of 46 padasekharams, it could be possible to conduct second paddy cultivation and agriculture in these padasekharams, and thereby increasing agricultural production. The major achievements include the following:

 

        •   Protected area - 2,818 Ha

        •   Total length of completed bund -128.636 Km

        •   Total No. of Motor thara /shed constructed- 61 Nos

        •   Total No. of Sluices Completed -68 Nos

        •   Total No. of Box / pipe culverts constructed -36 No

 

2. Mitigation of flood in Onattukara region comprising of 12 Watersheds in Kerala. The major achievements include the following.

 

        •   Total area protected- 5834ha

        •   Total length of bunds completed- 33.2km

        •   Total No of motorthara/shed constructed-1no

        •   Total No of culverts constructed- 11nos

        •   Total No of foot bridge constructed- 17 nos

        •   Total No of Vented cross bar (VCB)- 3 no

 

3. Mitigation of flooding 397 padasekharams of Kuttanad Taluk and 14 padasekharams of Veeyapuram Panchayat.By completing this scheme it is possible to do paddy cultivation twice in a year in all the above padasekharams. The major achievements include the following:

 

        •   Total area protected - 3871.75 Ha

        •   Total length of bunds completed -177.64 Km

        •   Total No of motorthara /shed constructed - 166 no

        •   Total No of Sluices Completed - 29 nos

        •   Total No of Box/Pipe culvert constructed- 24 no

        •   Total No of Thoombu - 587 nos

 

4. Reconstruction of bund at Puthenarayiram Padasekharam in D block: This Padasekharam in Pulinkunnu Grama Panchayath of Kuttanad Taluk, having an area of 211 ha, experienced a breach in the western bund during 2015 and 2016 because of high tides. Latest technology of precast pile and slab was adopted at the breached portion. Three layers of precast piles were driven in to the ground and connected by Tie Beams. Precast slabs were inserted in between precast piles and the bund was made by filling kayal clay in between piles. To reinforce this, 120 metre long new bund and extra berm was constructed using three rows of coconut piles. Kayal clay was used to fill the berm along the inside and outside of the breached portion. In 2020-21, 42 new works were taken up, which includes construction of outer bund for a length of 47.09 KM and desilting of thodes for a length of 50.84 KM. Out of the 42 works 23 were completed.

 

5. Modernisation of Thanneermukkom Barrage: Thannermukkam barrage, a Salt water barrier structure located at Thannermukkam, is built at the narrow region of Vembanad lake. Construction of bridge was (3rd phase-middle portion) completed with 28 stainless steel shutters and allied lifting mechanisms and opened for traffic on July 31, 2018. Radial gates and hydraulic system of 46 feet lock (14M) had 62 old shutters in the 1st and 2nd phase were replaced with stainless steel shutters. The work related to the hoisting mechanism of these shutters are completed, Renovation of 20 feet and 30 feet locks has been completed. After the completion of modernisation of Thannermukkam barrage, the flood water can easily drain out towards the estuaries.

 

6. Improving the efficiency of Thottapally Spillway: Thottapally spillway was constructed to expel the flood water to sea from Kuttanad areas. The actual design capacity of Thottappally spillway is 1800 cubic metre per second, but it got reduced to 600 cubic metre per second because of the reduced width of estuary from 380m to 150m. This reduction in the width of estuary was because of the formation of sand bars and casuarina plantation. The reduced width at the mouth, having decreased the efficiency of draining out flood waters in to sea, became a crucial factor for the floods in 2018. Therefore, to reinstate the width of 360m at the estuary mouth, 2,42,831.25 cubic meter of sand and obstructions were completely removed before July 23, 2020.

 

Kerala Water Resources Information System (Kerala-WRIS): Kerala-WRIS, is a web enabled platform wherein data related to water and its allied sectors are integrated, has been developed utilising funds under the Rebuild Kerala initiative (RKI). Kerala-WRIS acts as a single authoritative digital platform with specific modules such as weather, water Availability, water demand, water budgeting and auditing and the software development of all these modules have been completed.

 

Flood Forecasting and Early Warning System (FFEWS): Development of a system for coordinated operation of reservoirs integrated with flood forecasting and early warning system for Periyar river basin is progressing under National Hydrology Project (NHP). First Deliverable, viz ‘Submission of inception Report’ has been completed and second Deliverable, viz. ‘Report on Optimized RTDAS Network’ has been received and its evaluation is progressing. Establishing a

 

Real Time Data Acquisition System (RTDAS): Establishing of RTDAS progressing under NHP comprises of real time stations, such as 99 Tipping Bucket Rain Gauges (TBRGs), 56 Radar Level Sensors (RLSs) and 13 Automatic Weather Stations (AWSs). The contract value of the project is ₹12.50 crore. Installation of 91 Tipping Bucket Rain Gauges, 43 Radar Level Sensors and 12 Automatic Weather Stations has been completed.

 

 

Irrigation Status: As per the assessment of the Directorate of Economics and Statistics the net irrigated area in the state as on March 2010, is 3.86 lakh ha. and the gross area irrigated is 4.54 lakh ha. The net area irrigated has declined from 3.99 lakh ha during 2008-09 to 3.86 lakh ha in 2009-10. Only 16.34 per cent of the net cropped area is irrigated. The percentage of net area irrigated to net area has declined and percentage of gross irrigated area to gross cropped area records a slight increase during the year compared to the last year. During 2009-10 the net irrigated area registered a decline of 10.75 per cent and gross irrigated area by 0.64 percent compared to the previous year. During 2009-10, among the crops, paddy tops among the major crop supported by irrigation. It accounted for about 37 per cent followed by coconut (33%), banana (8%), arecanut (8%) and vegetables (4%) is given here.              

 

                 The source-wise area irrigated as on March 2013 is given here . As per the assessment of the Directorate of Economics and Statistics the net irrigated area in the state as on March 2013, is 3.96 lakh ha. and the gross area irrigated is 4.58 lakh ha. There is a decrease of 3.2 percent in the net irrigated area of the state in compared to the previous year of 2011-12. Gross irrigated area also decreased 6.7 percent during the period. Gross irrigated area to Gross Cropped Area in the period is 17.67 percent. During 2012-13, among the crops, coconut tops among the major crop supported by irrigation. It accounted for about 36 percent followed by paddy 32 percent, banana 10 percent, arecanut 8 percent and vegetable 4 percent. Details are given here. There has been a good progress in irrigated area under vegetable cultivation during the year and also an increase in the area under irrigation for banana cultivation compared to the previous year.

 

                  The source wise irrigation status as on March 2014 and 2015 are given here[PDF1, PDF2]. As per the assessment of the Directorate of Economics and Statistics, the net irrigated area in the State as on March 2015, is 4.14 lakh ha. and the gross area irrigated is 4.69 lakh ha. The percentage of increase is not significant compared to the previous year. During 2014-15, the percentage of Gross Irrigated Area to Gross Cropped Area was 17.80. The crop which benefitted the most during the period is coconut. It accounted for about 35.18 percent followed by paddy (32 percent), banana (10.19 percent), arecanut (7.2 percent) and vegetable (5.21 per cent). The details are given here.  There has been an increase in irrigated area for vegetable cultivation during 2014-15 compared to the previous year. Source-wise net irrigated area in 2017-18 is given here.

  

Net Area Irrigated  (Source-wise) 2017-18(in ha) in given here.

 

               The net irrigated area has fluctuated during the period 2015-16 to 2017-18. The net irrigated area that was 4.13 lakh ha in 2015-16, declined to 3.77 lakh ha in 2016-17 and showed an increase of 4 per cent to 3.92 lakh ha in 2017-18. During the period under review, wells contributed the major source of irrigation benefiting 1.23 lakh ha followed by irrigation canals which served an area of 0.76 lakh ha.

 

                 The gross irrigated area increased from 4.83 lakh ha in 2015-16 to 4.97 lakh ha in 2016-17 and further showed an increase of 8.4 per cent to 5.39 lakh in 2017-18. Details of Gross Irrigated area and the crops benefited out of this are given here. Gross Area Irrigated (Crop-wise) are given here. Source-wise net irrigated area in 2018-19 is given here.


Net Area Irrigated  (Source-wise) 2018-19(in ha) in given here.

 

                 The net irrigated area continues to expand over the period from 2016-17 to 2018-19. From 3.77 lakh ha in 2016-17, it increased to 3.92 lakh ha (2017-18) and to 4.04 lakh ha (2018-19). The main sources of irrigation are small stream, pond, well, bore well, lift, and minor irrigation. Wells provide irrigation to 1.24 lakh ha, whereas all other sources together (bore well, lift and minor irrigation, rivers, lakes, etc.) irrigates 1.47 lakh ha. The gross irrigated area has declined from 5.39 lakh ha (2017-18) to 4.89 lakh ha (2018-19). Details of gross irrigated area and the crops benefitted are given here. Table II.

  

            Even though coconut is the most irrigated crop, the extent of increase in area under irrigation is nominal i.e., the irrigated area has risen from 1.58 lakh ha (2017-18) to 1.59 lakh ha (2018-19). This should be viewed in tune with the area under coconut cultivation which continued to remain the same at 7.60 lakh ha during 2017-18 and 2018-19. But, the extent of irrigated area under paddy cultivation, the second most irrigated crop, shows a steep increase from 1.31 lakh ha (2016-17) to 1.45 lakh ha (2017-18) and to 1.54 lakh ha (2018-19). This increase in the irrigated area may be due to the increase in area under paddy cultivation.

 

          Acknowledging the fact that the net irrigated area reflects an increasing trend over the years, the decline in the gross irrigated area from 5.39 lakh ha (2017-18) to 4.89 lakh ha (2018-19) also needs to be cited. It may be inferred that this decline may be either due to non provision of irrigation facilities for the second crop or because of the absence of second crop itself. The decline in the total cropped area from 25.79 lakh ha (2017-18) to 25.68 lakh ha (2018-19) underlines the above point.  Details on net irrigated area (source-wise) in 2019-20 is given here.  Net Area Irrigated (source-wise)- 2019-20 is given here.

 

               The net irrigated area showed an increase over the period from 2017-18 to 2019-20, from 3.92 lakh ha (2017-18) to 4.04 lakh ha (2018-19) which further increased to 4.09 lakh ha (2019-20). But the gross irrigated area after having declined from 5.398 lakh ha (17-18) to 5.153 lakh ha (18-19), did not fluctuate much with the area remaining at 5.156 lakh ha in 2019-20. Details of gross irrigated area and the crops benefited are given here. Table II. 

 

               Though coconut and paddy continued to be the major benefited crops even in 2019-20, the irrigated area of both these crops has declined than the previous year. Gross irrigated area under paddy declined from 1.54 lakh ha (2018-19) to 1.50 lakh ha (2019-20) and the irrigated area of coconut fell from 1.59 lakh ha (2018-19) to 1.58 lakh ha (2019-20). The reduction in area under wetland paddy from 1.98 lakh ha (2018-19) to 1.91 lakh ha (2019-20) needs to be mentioned in this context. In 2019-20, the area under banana cultivation as well as the irrigated area showed an increase. While the area under banana increased from 0.52 lakh ha (2018-19) to 0.60 lakh ha (2019-20), the irrigated area of banana increased from 0.44 lakh ha (2018-19) to 0.52 lakh ha (2019-20). Vegetables also had a nominal increase in their irrigated area from 0.30 lakh ha (2018-19) to 0.31 lakh ha (2019-20). There is no change in the percentage of gross irrigated area to gross cropped area (20 per cent) in 2018-19 and 2019-20. 

 

                 As per the assessment of the Directorate of Economics and Statistics the net irrigated area in the State is 3.897 lakh ha and gross irrigated area is 5.215 lakh ha. The details of net irrigated area (source wise and district wise) during 2020-21 are shown below:  

 

                                         Net Area Irrigated (Source wise) (in Ha.)

Source

2018-19

2019-20

2020-21

Government canals

82975

85358

81801.33

Private canals

513

635

694.53

Tanks

49376

46779

43434.58

Wells

124020

117875

114121.37

Other sources

147512

153455

149741.87

Total

404396

404102

389793.68

Gross irrigated area

515388

517642.04

521478

Net area irrigated to net area sown (%)

20

20

19.50

Gross irrigated area to gross cropped area (%)

20

20

20.30

Irrigated area under paddy to total irrigated area (%)

30

29

30.61

Source: Directorate of Economics & Statistics Gok

 

Net Area Irrigated (Source Wise) - 2020-21 is given here.

 

                 The net irrigated area shows a decreasing trend from 4.043 lakh ha (2018-19) to 3.897 lakh ha in (2020-21). But, the gross irrigated area showed a marginal increase from 5.153 lakh ha (2018-19) to 5.215 lakh ha (2020-21). Details of gross irrigated area and the crops benefitted are given here.

  

 

Gross Area Irrigated (Crop-wise) (in ha.)

Crops

2018-19

2019-20

2020-21

Paddy

154138

150009

159639.54

Vegetables

30112

31256

28844.56

Coconut

159492

158584

158834.38

Areca nut

33353

33093

31902.86

Nutmeg

19840

19861

19861

Clove

113

110

121

Banana

44820

52044

52365.64

Betel leaves

236

252

252.43

Sugarcane

1012

950

920.73

Others

72272

71484