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Drainage Protects I r r igat ion Investments

International Institute for Land Reclamation and Improvement / ILRI

Colophon

Publisher Alterra

Idea and Supervision Ir. H.P. Ritzema, Alterra-ILRIDr. S. Raman, Gujarat Agricultural UniversityDr. T.V. Satyanarayana, Andhra Pradesh Agricultural UniversityDr.ir. J. Boonstra, Alterra-ILRI

Illustrations Indo-Dutch Network ProjectAlterra-ILRI archive

Design K. Hulsteijn (Team Graphic Design and Desktop Publishing, Alterra)

Printing Drukkerij Kerckebosch b.v. Zeist

For further information:

J. (Hans) BoonstraAlterra - ILRI PO Box 476700 AA WageningenThe NetherlandsPhone: +31 (0) 317 49 55 60E.mail: [email protected] or www.ilri.nl

Drainage Protects Irrigation Investments

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Map of India showing network centres

Co-ordinating Centre

Network Centre

State Boundary

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BACKGROUND OF THE PROJECT

The Indo-Dutch Network Operational ResearchProject on Drainage and Water Management forControl of Salinity and Waterlogging in CanalCommands (1995-2002) was implemented jointly bythe Government of India through the Indian Councilof Agricultural Research (ICAR) and the Governmentof The Netherlands through the Royal NetherlandsEmbassy (RNE) in India. The Implementing agenciesin India were:• Central Soil Salinity Research Institute (CSSRI),

Karnal, Haryana• Acharya N G Ranga Agricultural University

(ANGRAU), Indo-Dutch Network Project, Bapatla,Andhra Pradesh

• Gujarat Agricultural University (GAU), Soil andWater Management Research Institute, Navsari,Gujarat

• University of Agricultural SciencesDharwad(UASD), Agricultural Research Station,Bheemarayanagudi, Karnataka

• Rajasthan Agricultural University (RAU),Agricultural Research Sub-Station, Hanumangarh,Rajasthan

CSSRI, Karnal was the co-ordinating agency andfocal point for all the other Network Centres andtechnical assistance to the project was provided bythe International Institute for Land Reclamation andImprovement (Alterra-ILRI), Wageningen, TheNetherlands.

The Project was carried out with the following fourlong-term, overall objectives:1. Increase of agricultural production from water

logged and salt affected areas throughapplication of proper soil and water managementpractices along with other agro-techniques

2. Prevention of deterioration of productive landsthrough adoption of appropriate soil and watermanagement practices

3. Improvement of socio-economic conditions ofsmall and marginal farmers of these lands

4. Development of expertise for handlingreclamation projects in India.

From these two Project Objectives were derived:• Strengthened research capacity of CSSRI and the

four State Centres, especially in the field of waterlogging and salinity control;

• Enhanced awareness on drainage and relatedwater management for the control of waterlogging and soil salinity at State and Central level.

The overall and project objectives were translated ineight project results:1. A methodology for identification of waterlogging

and soil salinity conditions by remote sensing2. Recommendations on waterlogging and salinity

control based on drainage pilot area research3. Appraisal of irrigation and drainage practices by

computer simulations4. Improved human resources at CSSRI and the four

State Agricultural Universities through training5. Operational Training Centre at CSSRI to conduct

national training programmes6. Enhanced awareness at State and Central Level

on the necessity of an agricultural drainage policy7. Enhanced awareness at farmers' level on

improved irrigation and drainage for control ofwaterlogging and salinity

8. Advice on drainage and related watermanagement

With the intention of developing location-specificdrainage technologies for reclamation of saltaffected and waterlogged agricultural lands indifferent agro-climatic zones in the country, eightpilot areas were selected. The drainage strategiesdeveloped on the basis of the results of theinvestigations are presented in this document.

The technical and financial assistance,encouragement and co-operation extended byvarious organizations and personnel are gratefullyacknowledged.

5

The problem of increasing salinity caused by the riseof water table due to lack or drainage is consideredas a major environmental problem that threatens thecapital investment in irrigated agriculture and itssustainability. Drainage has not been givenimportance as much as irrigation by the individualsas well as the governmental agencies. Sporadicresearch attempts like All India Co-ordinatedResearch Projects on Agricultural Drainage weremade in the past for combatting the landdegradation; however, wide spread adoption ofappropriate drainage measures has not been taken.The situation demands concerted Research andDevelopment efforts to bring all the affected areasback to profitable farming with increasedagricultural production. This document addressesthe following three issues:• Why Subsurface Drainage is needed?• How Subsurface Drainage works?• What Challenges make Subsurface Drainage work?

The recommendations and strategies presented inthis document are based on research conducted ineight pilot areas and one large-scale monitoringprogramme in 5 agro-ecological subregions of India.Basic features of these pilot areas are given below.

1INTRODUCTION

Agriculture is a key sector in India's economy,contributing about 35% of the Gross DomesticProduct and employing 65% of its adult population.Of the total population of over 1000 million, morethan 30% live below the poverty line and about 75%lives in rural areas, depending directly or indirectlyon agriculture. One-third of the agricultural labourforce are women and agriculture is the main sourceof employment for women in rural areas. Annualagricultural growth has been modest at 2.6% perannum over the last 25 years. Development plans ofthe Government of India and State Governments givepriority to alleviating poverty and creatingemployment, particularly in rural areas. Considerableirrigation potential has been created in India tosustain agricultural production against the vagariesof rainfall that is scarce and unevenly distributed inspace and time.

The introduction of irrigated agriculture in arid andsemi-arid regions of the country has resulted in thedevelopment of the twin problem of waterloggingand soil salinization, with considerable areas eithergoing out of production or experiencing reducedyield. It is estimated than an area of nearly 8.4million ha is affected by soil salinity and alkalinity, ofwhich about 5.5 million ha also waterlogged, mainlyin the irrigation canal commands and 2.5 million hain the coastal areas.

Introduction of large scale irrigation

6

Gohana and SamplaThe Gohana monitoring site is located in the WesternJamuna Canal command in Haryana. The climate issemi-arid, monsoon with a mean annual rainfall of550 mm and an evapotranspiration of 1650 m. Themain crops include rice, sorghum, pearl millet andsugarcane during kharif (monsoon season) andwheat, mustard, barley and berseem during Rabi(dry season). The Gohana monitoring site is part ofthe Haryana Operational Pilot Project, a project toinstall a subsurface drainage system in saline andwaterlogged soils of two 1,000 ha pilot sites. Themain problems in the area are saline groundwater,high water tables and surface water stagnationduring kharif.

Sampla pilot area is also located in the WesternJamuna Canal Command in Haryana, just south ofGohana. The pilot area that was constructed in 1984was used to study the long-term effects ofsubsurface drainage.

Islampur and DevapurIslampur and Devapur pilot areas are located in theUpper Krishna Project (UKP) in Karnataka. Theclimate is semi-arid tropical monsoon with a meanannual rainfall of 768 mm and a potentialevapotranspiration of 2176 mm. The area isirrigated with good quality canal water and the maincrops are paddy, cotton, chillies, wheat and Rabi

sorghum. Most farmers are illiterate and poor, landholding varying between 1 and 2 ha. The variouscauses of water logging and salinity are poorlydrainable black soils, seepage from the canalnetwork, lack of land development, inefficientirrigation practices and inadequate drainage.

Konanki and UppugunduruKonanki and Uppugunduru are located inrespectively the Nagarjunasagar Project Right CanalCommand and the Krishna Western Delta in AndhraPradesh. The climate is predominantly semi-arid toarid with a mean annual rainfall of 768 to 844 mmand an evapotranspiration of 1600 mm. The maincrop in the area is rice. Soils are sandy clay to clayloam. The average farm size is about 0.5 ha; themajority of the farmers are illiterate or have onlyprimary education and are relatively poor. Yields arelow due to water logging and salinity problems.

LakhuwaliLakhuwali pilot area is located in the Indira GandhiNahar Pariyojana Command in north-west Rajasthan.The climate is arid to semi-arid with a mean annualrainfall of 297 mm and evaporation of 1560 mm.The area irrigated with good quality irrigation waterfrom the Indira Gandhi Main Canal, the main cropsare cotton and wheat. The soil is a coarse texturedsandy soil; a calcareous layer at shallow depthresults in the formation of a perched water table.

Uppugunduru pilot area Islampur pilot area

7

Segwa and SisodraSegwa and Sisodra pilot areas are located in theUkai-Kakrapar Command in south Gujarat. Segwasituated in the middle branch of the command has amean annual rainfall of 1500 mm and anevaporation of 1765 mm; Sisodra situated in thelower part of the command receives less rainfall(850 mm/year) but has approximately the sameevaporation (1670 mm/year). Segwa is partlyirrigated with good quality canal water and partlywith poor quality groundwater. Sisodra completelydepends on canal water, which is in short supply sothat part of the drainage water is reused. Soils areheavy (black cotton, clay content > 45%); the maincrops are sugarcane and rice. Farmers in Segwaare relatively well-educated and with an averagefarmer size of 3.6 ha well-to-do. In Sisodra, farmersare poorer, have a lower education level and smallerfarmer size (2.1 ha). Both areas have good outletconditions, but suffer from waterlogging andsalinity, partly because of heavy rainfall duringmonsoon and inefficient irrigation methods.

In all these pilot areas, subsurface drainagesystems, consisting of open and pipe drains withdifferent depth/spacing combinations were installedin farmer's fields. The design was based on theresults of comprehensive diagnostic surveys andsoil reclamation criteria. For the construction,whenever possible, indigenous materials (pipes andenvelopes) and equipment were used.

Segwa pilot area

Sisodra pilot area

Lakhuwali pilot area

The area has no natural drainage outlet. After theintroduction of irrigation to the area, thegroundwater table rose at a rate of about 1 m/year,resulting in complete waterlogged conditions. Thefarmers are poor and illiterate with an average farmsize of 2.3 ha.

8

Pilot Area

Konanki

Uppugunduru

Segwa

SisodraGohanaSamplaIslampur/Devapur

Lakhuwali

Summary of the various drainage systems in the pilot areas

State

AndhraPradeshAndhraPradeshGujarat

GujaratHaryanaHaryanaKarnataka

Rajasthan

Size (ha)

20

21

188

1601200

100180

75

Type of Drainage System

• Composite pipe drainage• Composite open drainage• Composite pipe drainage• Composite open drainage• Composite pipe drainage• Singular pipe drainage• Composite open drainage• Composite pipe drainage• Composite pipe drainage• Composite pipe drainage• Singular pipe drainage• Composite open drainage• Composite pipe drainage

Outfall conditions

Gravity

Pumped

Gravity

GravityPumpedPumpedGravity

Pumped

Through a monitoring programme, the quality andeffectiveness of the drainage systems wereevaluated. The research programme was conductedin close co-operation with the farmers; farmers werealso advised and supported on the optimumagricultural practices during reclamation.

9

In the monsoon-type climatic conditions in India thecontrol of waterlogging and salinity starts with theremoval of excess water from the land surface bysurface drainage. Timely removal of this excesswater is especially important for non-rice crops.However, surface drainage alone is often notsufficient. It should be integrated with subsurfacedrainage.

In most canal commands of India, the major share ofirrigation water is supplied during the Kharif season(July to Oct) and the remaining part during Rabi (Novto Jan). During the Kharif season, the averagemonthly rainfall is more than the averageevaporation; as a result, the water table starts risingfrom July and comes close to the ground surface atthe end of monsoon.

As mentioned earlier, in addition to rainfall, largequantities of irrigation water are also applied duringJuly to January. To prevent waterlogging conditions,drainage is needed to remove excess water duringthe Kharif season and afterwards till the canalsupplies are completely stopped; otherwise yieldreduction caused by waterlogging will occur.

Irrigation studies conducted in the Segwa pilot area

Segwa Pilot area is irrigated from various sources: 40% by canal water through the Segwa Minor, 37% bywells, 14% by conjunctive use, 4 % by re-using drainage water and the remaining part is not irrigated andused as grassland. Irrigation water supply through the Segwa Minor is abundant and of good quality (ECi =0.3 dS/m). It exceeds the crop water requirements of the main crops cultivated in the area: sugarcane(43%), paddy (21%), fallow (12%) and non-irrigated grassland (25%). The quality of the well water is poorerand is around 1.7 dS/m.

Design and actual canal supplies in the Segwa Minor differ greatly and the actual supplies by far exceed thecrop water requirements for sugarcane:

Actual supply to fields (mm)Effective rainfallCrop water requirements sugarcane (CWRS)CWRS with 65% application efficiency (mm)

Excess/Deficit (= Actual Supply - CWR in mm)

Kharif

1332499400

0

1332

Rabi

779

674

105

Summer

814

1238

-425

Year

2924

1912

1012

Import of excess waterWith a misconception that more they irrigate, moreyields they will get, farmers apply huge quantities ofcanal water. As the canal irrigation water is heavilysubsidised, the withdrawal of ground water forirrigation purpose has almost stopped (as it iscostlier than canal water). Added to this, there arelosses from canals due to seepage. These factorshave disturbed the hydrologic equilibrium of theground water basin and the water table in theseareas has started to rise at an alarming rate.

2WHY DRAINAGE IS NEEDED?

Waterlogging in Rajasthan

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Import of saltsThe introduction of canal irrigation not only bringsthe much needed water, but also imports salts aseven good quality irrigation water containsconsiderable amounts of salts. The import of salts isfurther aggravated because with the introduction ofcanal irrigation system in dry land areas, the farmersstarted growing high water demand crops.Subsequently considerable amounts of salts areadded to the soil profile.

Crop

BananaCabbage CottonOkraPaddySugarcaneSorghum

Irrigationmm/season

1920480280780

12001500

240

Canal waterEC =0.3 dS/m

3.60.90.51.52.32.90.5

GroundwaterEC =1.0 dS/m

11.93.01.85.07.79.61.6

GroundwaterEC =2.0 dS/m

23.86.13.6

10.015.419.2

3.2

Year after year salts are accumulated in the profileand ultimately affecting crop yields. The rise in watertable and build up of salinity reduces crop yields bycausing poor establishment of the crop anddamaging the root system. Yields are reduced inproportion to the increase in the salt build up in theprofile.

Salts added to soil profile through irrigation per season.

Salts imported (t/ha)

Salt build-up in Rajasthan

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Change in Cropping PatternIn the canal command areas, where the importedsurface water is made available at a highlysubsidized price, the farmers have not followed thecropping pattern as suggested by the projectauthorities and started growing water loving cropslike paddy. Before the introduction of canal irrigationmainly rainfed crops like cotton, chillies, groundnut,coriander, bajra and jowar were grown duringsouthwest monsoon (Kharif) and lands were keptfallow during Rabi and summer. Once the goodquality irrigation water became available by theintroduction of canal irrigation, farmers were able togrow paddy besides the above crops. Farmers,however, did not follow the recommended croppingpattern, and ceased to cultivate water-saving cropslike sorghum in favour of water-loving crop likepaddy. The high yielding water-loving rice alsoreplaces rainfed varieties of rice. Subsequently, theimport, including the dissolved salts, hasconsiderably increased.

Drainage Protects IrrigationInvestmentsAlthough the benefits of the introduction of canalirrigation are without dispute, it is clear that the twomajor site-effects (waterlogging and salinization) areserious threats to the sustainability of irrigatedagriculture. For example, in the Surat Branch of theUkai-Kakrapar Command (36 000 ha) the abovementioned site-effects have seriously increased thearea affected by high water tables and the areasaffected by salinity is about 33% of the totalcommand area.

Suggested0

45403530252015105

1957 - 61 1991 - 94

Paddy Sugercane

Combine harvesting rice crop

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The rising trend of the groundwater and the increasein soil salinity clearly indicates that drainage isneeded to sustain agriculture in irrigated lands.Besides sustaining agriculture, drainage will alsoimprove health conditions for the rural population asit will increase food security, reduce flooding (andthus improve access to fields and farmhouses) andreduce the occurrence of vector-born diseasesthrough the elimination of standing-water. Evenmore than irrigation, drainage is a communal activityand can not be effective as long as farmers do notco-operate. Furthermore, the drainage infrastructureespecially the main drainage system will not only actfor the disposal of excess water from the farmersfields but also serves rural residents as well asindustry: drains and drainage water can be used asa source of water, not only in the area itself but alsodownstream. Drains also serve to disposewastewater from rural settlements, cities andindustries, thus should be considered as publicgoods.

Rice crop after introduction of subsurface drainage

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Subsurface Drainage as a Measure toCombat Waterlogging and SalinityThe studies conducted at the various pilot areasclearly proved that, under the prevailing soils, agro-climatic conditions and social settings found in theproject areas, subsurface drainage, either by pipe oropen drains, is a technically feasible, cost-effectiveand socially acceptable technology to reclaim waterlogged and saline lands and to sustain agriculture inirrigation commands. Significant increases in cropyield were obtained within one or two seasons afterthe installation of the subsurface drainage system.

The significant increase in crop production can beattributed to the direct effects of the introduction ofsubsurface drainage, i.e. the control of the watertable and a decrease in soil salinity. Monitoring theperformance of subsurface drainage systems clearlyshowed that the system effectively controls thewater table and the soil salinity in the root zone. Thewater tables can be controlled at a relatively shallowdepth: 0.5 - 1.5 m (depending on the crop) or evenshallower in paddy fields. These shallow water tablesavoid excessive drainage while at the same timeharmful salts that are brought in by the irrigationwater are effectively removed.

3HOW DRAINAGE WORKS ?

Wheat (Gohana)

Rice (Islampur)

Wheat (Sampla)

Wheat (lakhuwali)

Cotton (Devapur)

Rice (Sisodra)

Sugarcane (Segwa)

Rice (Uppugunduru)

Rice (Konanki)

Post drainage

Pre drainage

Relative yield (%)

0 20 40 60 80 100

Open drain (A) or pipe drain (B) can effectively controlwaterlogging and salinity

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Apart from the increase in yields of the traditionallygrown crops like wheat, sugarcane and rice, theintroduction of subsurface drainage has also lead toincreasing cropping intensity: highly renumerativecrops were introduced like brinjal, blackgram,chillies, greengram as a second crop.

Subsurface drainage is also an eco-friendlytechnology. The pilot area studies revealed that:• Drainage effluent does not contain excessive

amounts of nitrate or other toxic elements;• Drainage water can be re-used for irrigation either

directly or in conjunction with good qualityirrigation water;

• During Rabi and summer, drainage water has ahigh salt concentration, making it often unsuitablefor re-use. In such cases, the option to temporallystop the discharge for disposal at a later stageshould be considered;

• During the monsoon (Kharif) season, drainagewater quality is much better, because of thedilution effect of the rains. At this time the water isnot required for irrigation in many cases. In suchcircumstances, excess water can be disposed offin the natural drainage system.

It should be realised, however, that subsurfacedrainage systems can only be successful incontrolling salinity, if sufficient good quality irrigation

water or monsoon rainfall is available for leachingand that supplementary measures in soil & watermanagement like application gypsum, salt-resistance varieties, irrigation efficiencyimprovement, etc. will enhance the positive effectsof horizontal subsurface drainage.

Brinjal introduced as new crop (Segwa pilot area)

Chillies introduced as new crop (Devapur pilot area)

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Design specifications for subsurfacedrainage systemsHorizontal subsurface drainage systems can beinstalled with either open or pipe drains with drainspacing between 45 and 150 m and drain depthsbetween 0.90 and 1.50 m. The agro-climatic andsoil conditions determine the most appropriatecombination of drain depth and spacing. To avoidcosts for pumping the drainage effluent, gravityoutlets should be preferred by reducing the draindepth and narrowing the spacing.

Singular subsurface drainage systems, with (pipe oropen) field drains directly discharging in an openmain drain or natural stream (Nala) proved to bemore cost-effective than a composite system. Ifsuch outlet conditions are not available, a compositesystem, consisting of field and collector pipe drains,is required. If gravity drainage is not an option,pumping the drainage effluent should be considered.

Horizontal subsurface drainage can be made stillmore effective by introducing controlled systems tohalt the drainage flow in times of water scarcity andto prevent excessive leaching of valuable nutrients.This will also avoid excessive loss of irrigation waterin rice fields.

Subsurface drainage systems consisting of opendrains (depth up to 1.0 m) proved to be the mostcost-effective method. Adverse soil conditions,operation and maintenance requirements, loss ofland, and social settings, however, restrict their use.Alternatively, corrugated, perforated, plastic (PVC)pipes with a diameter of 100 mm or more can beused.

Pilot Area

Konanki/Uppugunduru

Segwa/Sisodra

Gohana/Sampla

Islampur/Devapur

Lakhuwali

State

Andhra PradeshGujarat

Haryana

Karnataka

Rajasthan

Type

• Composite pipe• Composite open• Composite pipe• Singular pipe• Composite open• Composite pipe

• Composite pipe• Singular pipe• Singular ope• Composite pipe

Spacing (m)

6075

45

6750

50

150

Depth (m)

1.01.0-1.2

0.9-1.2

1.61.2-1.5

1.0-1.2

1.2

Costs (Rs/ha)

18,5004,500

20,40017,400

8,300 18,00022,30024,00019,500

8,60021,000

Summary of design specifications based on pilot area research

Manual installation of open drains

For the heavy soils, there is no need for an envelopematerial. Pipe drains with and without envelopesperformed equally effectively in these soils andexcavation programmes, conducted in the variouspilot areas one and two years after installation,showed only traces of sedimentation. For the lightersoils, field tests are recommended to select themost appropriate envelope material. Non-wovenpolypropylene filter material performed best,although it is rather expensive.

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Cost of installation (Rs/ha)Cost of cultivation* (Rs/ha)Yield (t/ha)Gross income (Rs/ha)Net Present Value (Rs/ha)Benefit/cost ratio (-)Internal Rate of Return (%)Pay-back period (years)

Singular open drains

Composite open drainsSingular pipe drainsComposite pipe drains

Rs/m

22 - 33

317785

Rs/m

38

437892

Rs/m

30 - 35

558098

Rs/ha

4,8005,8008,800

13,30016,400

Rs/ha

8,300

9,50017,40020,400

Control plots

--31,286

7863,555

Drained plots

20,40041,143

10585,50075,000

1.7583

Economic returns of subsurface drainage systems in the drainage pilot areas were also calculated.The recommended drain spacing (45 m) has, even for the most costly package (the composite pipedrainage system), positive economic returns:

Cost and Benefit Studies conducted in Segwa and Sisodra Pilot Areas.

For assessing the economic viability of the subsurface drainage systems, the crop yield and cost ofimplementation and cultivation were recorded.

Cost of subsurface drainage

30 m spacing 45 m spacing 60 m spacing

Two methods for the construction of subsurfacedrainage system are available: manual andmechanical installation. The project has developedand successfully tested a combination of these twomethods using conventional machinery. Under Indianconditions, with its abundant labour force, thiscombined method is most promising and needs tobe tried at more places. The presently availableguidelines on the need and selection of an envelopematerial seem appropriate. The only exception isthe coefficient of uniformity, that as a criterion fordeciding on the need of an envelope, should not beused for the Indian conditions.

The installation cost of subsurface drainage systemwith different spacing and envelope material wererecorded for economic viability assessment.Horizontal subsurface drainage systems areextremely benefical. For the most expensive(composite pipe drainage) systems, cost benefitratios are in the range from 1.1 to 3.6, internal ratesof return in the range from 18 to 58%, and pay backperiods in the range from 3 to 10 years.

Manual installation of pipe drains

Rs/ha

7,200 - 10,80010,20025,70028,300

17

Supplementary activities in soil andwater managementA shallow water table can help to meet part of theirrigation water requirements of crops. Under theseconditions, irrigation water requirements can bereduced by 20-25%. This can be achieved either byreducing the depth of irrigation water application orby reducing irrigation frequency.

Reduction in canal water supply is commonlyadvocated as a mitigate measure to control waterlogging. Although technically sound, the studiesrevealed that:• So far technical and management measures to

improve irrigation water management have notpercolated to the farming community in the pilotareas constructed by the project. Therefore, moresystematic efforts need to be made to generateawareness on irrigation water management amongthe farming community;

• In one command, the water supply on an annualbasis is more than the demand. However, in spiteof the efforts made so far at all levels, it has notbeen possible to reduce water allowance;

• The well-known supply gap between the head-endand tail end farmers is yet unsolved. Tail-endfarmers will never agree to a reduction in theoverall water supply, since they are already short ofwater and any reduction in water allowances wouldaccentuate this gap.

The role of farmersThe farmers’ role in adoption of drainage technologyis very important in command areas as it is acollective effort of the farmers and their spouseswho have to take the responsibility of operation andmaintenance of the subsurface system. In the pilotareas, there were generally no problems inpersuading the farmers to adopt drainagetechnology as the farmers were involved in thedesign, construction, operation and maintenance ofsubsurface drainage system.

The farmers’ confidence in the drainage technologyhad to be sought before implementation of theproject and continuous interaction with the farmersand also with their family members is also importantelement for success of the transfer of thetechnology. At the pilot areas, farmers’ confidencewas first obtained by enlightening the probablefuture benefits the farm families may derive with theinstallation of a subsurface drainage system in theirfields. At some pilot areas, like Uppugunduru, thestructural co-operation of the farmers was relativelyeasy from the very beginning, as there was alreadya co-operative society functioning for the last 75years.

Project staff meeting pilot area farmers

18

Farmers attitude to Drainage as a tool to combat Water logging and Salinity

The attitude of the farmers and farm women was analyzed by conducting base line survey on socio-economicand gender aspects at both the Konanki and Uppugunduru pilot areas. All pilot area farmers and theirspouses participate in the survey. This survey helped very much to understand the attitude of the farmersand farm women towards new technology.

The main observations of the base line survey are:• 90% of farmer's farm holdings were less than one hectare in both pilot areas;• Farmer's literacy was 65%;• Farmers fully agreed that their land needs to be addressed to overcome water logging and Salinityproblems.

And after the installation of the subsurface drainage systems:• Farmers were fully convinced that drainage technology brings prosperity as technology has increased the

yields considerably after system installation;• The improvement in land quality was felt by the farmers;• The land problems such as poor land quality, low yields, less quality of fodder and low cropping intensity

due to waterlogging and salinity conditions were reduced;• Asset values increased by 175 %;• Farmers understood fully the operational and maintenance issues such as maintenance of pipe drain and

open drainage systems, pumping of drainage effluent and that drainage is not an individual responsibilitybut a collective activity in which they have to cooperate among each other.

Gender issues also indicated the following:• Women perception towards technology has changed positively;• Knowledge on waterlogging and salinity consequences like effects on yield, farm income and standard of

living has increased among women;• The drudgery of women in agricultural operations was considerably reduced;• The farm women preferred more and more interactions with scientists as it helped to address some of

their farm and home management problems;• Both farmers and their wives are fully convinced that drainage gives both direct and indirect benefits that

give prosperity in the long run.

19

Institutional and policy issuesThe role of the State Government is crucial sincedrainage requires a regional infrastructure andaffects generally more than one farmer. To reversethe rising trend of land being affected bywaterlogging and salinity the State Governmentshould take the lead and prepare a Drainage Policyemphasizing on a time bound action plan to reclaimthese waterlogged and salt-affected lands and tosafeguard other irrigated lands against these twinproblems.

Implementation of subsurface drainage shouldgraduate from the pilot areas to full-fledged drainageprograms under the relevant Departments. Thebenefits often go beyond the direct interest of theconcerned farmers, therefore the Governmentshould also (pre)finance complete or part of thecosts. Government support is recommended toovercome constraints such as:

4WHAT CHALLENGES MAKE DRAINAGE WORK?

• Limited knowledge on drainage as a tool tocombat waterlogging and salinity within theexisting (government & private) organizationsinvolved in irrigated agriculture;

• Limited capacity to implement drainage projects;• Limited financial resources especially for those

farmers whose land has been gone out ofcultivation due to waterlogging and salinity.

• Reclamation of waterlogged and salt-affected soilsalthough cost effective seems to be beyond thereach of the small and marginal farmers as far asthe initial investments are concerned. Funding ofsuch programmes should come from thegovernment which can be recovered in interestfree instalments along with the land revenue andirrigation water charges.

20

The most important policy measure could be aGovernment decision to treat the reclamation ofwaterlogged and salinity-affected areas in irrigationprojects as equivalent in importance to the creationof fresh irrigation potential or its utilisation. Anotherpolicy decision is required to provide for drainagerelated needs in all new projects right at the time ofinception of the projects, eg. designing the maindrainage systems in such a way that later onsingular subsurface drainage systems can beinstalled.

An approach, which involves location specificsolutions and technologies being employed byintegrated multi-disciplinary organisations of theState Government working jointly with the WaterUsers Associations who have fully adoptedparticipatory irrigation water management, shouldbe adopted. It is also recommended to formulate aState-level Advisory Group on Drainage to suggestremedial measures on situation basis from time totime.

Pre-drainage investigationsDrainage measures are generally location specificand vary according to soil, climate, irrigation,cropping pattern, socio-economic conditions of thefarmer etc. It is advisable to foresee the minimumdata requirements for the design and monitoring theperformance of drainage systems and plan forobtaining these data for each specific project. Thefollowing information need to be collected/considered before drainage systems are executed:• Remotely sensed data to identify salt affected

soils and waterlogged soils on large scales. Atleast 1:50000 scale should be made availablewhich is found to be economically feasible.

• Topographic maps to collect ground truth.• Information on hydraulic conductivity, soil porosity,

infiltration rate, salinity, depth to impermeablelayer, quality of ground water and irrigation water.

Mapping by Remote Sensing

• Existing performance of irrigation and drainagesystems in detail.

• Ground water data including fluctuations, qualityand degree of exploitation over years.

• Provision for the disposal of water from the maingravity/pumped outlet.

• Information on the mode of availability andtransport of the equipment and materials requiredfor laying the system.

• Agro meteorological data consisting of rainfallpattern, evapotranspiration losses, croppingpattern.

• Detailed information on yields, cost-benefit studiesof similar type of experiment elsewhere.

• Socio-economic conditions of the farmers in termsof willingness to participate and contribute todrainage works and forming a co-operative groupfor better performance of the system in future.

Godavari Delta: Restoration of the natural drainage network

After independence the main drainage system in the Godavari Delta gradually deteriorated: bunds werewidened to be used for shelter and the cultivation of tree and major open drains were poorly maintained. Dueto this poor maintenance, heavy rains in 1986 caused severe flooding and most crops were lost. The mainreason attributed to these floods was the blocking of major open drains. After the floods, the Governmenttook up a large scale rehabilitation project to dig out and widen the open drains to restore their original crosssections. As a result of the rehabilitation of the main drainage system, the heavy monsoon rains of 1996 (thesame order of magnitude in 1986) did not result in serious flooding and the standing crop was saved.

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Drainage system requirementsIn irrigated areas, the restoration of the (natural)drainage capacity, which is generally disrupted bythe construction of the irrigation canal networks orother development activities, will considerablyreduce the need (or intensity) of the subsurfacedrainage and will furthermore be needed to providesave outlet conditions. The availability of a goodoutlet for safe disposal of the drainage effluent(including the leached salts) is a prerequisite tomake subsurface drainage a success. In land lockedareas, 10 to 17 % of the land area can be convertedinto an evaporation/storage tank to store anddispose off the water at a later stage.Investments in subsurface drainage should go handin hand with investments in improving irrigationefficiency. Reducing irrigation water losses can not

only reduce the problem of waterlogging and salinitybut will also reduce the overall cost in subsurfacedrainage. Subsurface drainage can be made stillmore effective by introducing controlled systems tohalt the drainage flow in times of water scarcity andto prevent excessive leaching of valuable nutrients.This will also avoid excessive loss of irrigation waterin paddy fields.

Post-drainage investigationsContinuous monitoring should be carried out for 10-15 years after installation of systems to assess theperformance of the system and to refine designcriteria whenever needed. As a part of themonitoring the performance of drainage systems,the arrangements should be made to measure/studythe following: water table fluctuations, dischargefrom pipe and open drains, changes in soil salinity,changes in crop yields and cropping pattern, regularmaintenance of open drains.

Computer models can be used to calculate the saltand water balance of the systems and to predict andoptimize the performance of system which in turncan influence the payback periods.

Reconstruction of natural drainage.

Monitoring of depth to water table

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Analysis of Salt and Water Balances at Konanki by Computer Simulation

Long-term field experiment are required to develop suitable salt and water balance strategies, but areexpensive, site specific and time consuming. Simulation models, however, can be used to test a wider rangeof conditions than met in the field. Once calibrated using experimental information, models could aid asmanagement and decision making tools to obtain quantitative guidance in developing and evaluating drainageand irrigation strategies.

A hydro salinity model SALTMOD was used to analyze salt and water balances at Konanki pilot area to makelong-term predictions of soil salinity and depth to water table. For calibration the leaching efficiency in respectto root zone salinity was simulated and compared with observed data. The model predicts that due to theexistence of drainage system, the root zone soil water salinity will be reduced to 4, 3 and 2.5 dS/m (from aninitial value of 11.5 dS/m) during the first, second and third seasons within six years, with is in goodagreement with the measured data. Next, the model was used to simulate different drain depth scenarios. Italso predicts that closer than the present spacing will not be of any advantage and further deepening of thedrains from the present depth of 1 m to 1.4 m will not have any better influence on reduction of the root zonesalinity than in the present situation.

14121086420

5

4

3

2

1

0

0

1 2 3 4 6 8 9 10

3 8 12 15 20 24 27 32

Fir = 0.2Fir = 0.4Fir = 0.6Fir = 0.8Fir = 1.0

Soi

l wat

er s

alin

ity, d

S/n

Soi

l wat

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alin

ity, d

S/n

Time after installation of drains (months)

Time after installation of drains (years)

Root zone salinity during second (paddy crop) seasons as influenced by drain depth

Dd = 0.6Dd = 0.8Dd = 1.0Dd = 1.2Dd = 1.4

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Capacity buildingThe project enhanced the capacity building at thefour State Agricultural Universities by adopting astep-wise approach in technology transfer throughtraining:• Basic training by sending project staff to regular

training courses at specialised centres in Indiaand abroad;

• Advanced training by sending project staff andselected university staff of the four NetworkCentres to tailor-made training course on subjectmatters in India;

• Project expert meetings in which project staffexchanged experiences, discussed andsynchronised their research activities;

• In-depth training by sending project staff forcollaborative research programmes atUniversities and specialised researchorganisations abroad.

These training activities were supplemented by in-service training of visiting consultants at theNetwork Centres; study tours to acquaint seniorproject staff with practices from elsewhere and todisseminate the knowledge and experiencesobtained in the project to a broader audience byparticipation in international workshops andsymposia; and National Training courses to

Tailor-made training of project staff

Scale model of Konanki pilot area for farmers’ fair

disseminate the knowledge and experiencesobtained by the project within India.

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Participatory approachThe universities created awareness on the need fordrainage in their states by:• Conducting farmers' days to promote the benefits

of drainage• Publishing leaflets, folders and training manuals in

local language• Making broadcasts on radio and television• Excursions for government officials to the various

pilot areas• Organising state level workshops.

The above has resulted among others thatprogressive farmers have approached theuniversities for technical advice to install subsurfacedrainage in their own lands at their own costs.

Group action is very essential in implementation ofdrainage system as drainage involves more thanone farmer. Drainage requires also a regionalinfrastructure to safely discharge the excessdrainage water, thus farmers should realize thatthey have to co-operate with each other and withregional agencies. In canal command areas paddyis a principal crop and it warrants a mutual co-operation between the farmers on every aspect ofcultivation which requires collective effort inimplementation of drainage system.

Impact analysisAfter the implementation of subsurface drainagesystems surveys were conducted to assess farmer'sviews on the technical feasibility and economicviability and perceptions towards subsurfacedrainage. The survey revealed that:• Farmers favour system installation on large scale;• Farmers feel that there is a need for Government

intervention in solving the problems;• Farmers are willing to participate in future

drainage projects, but expect that a fair share ofthe costs is paid by the Government;

• Farmers are willing to take up the operation andmaintenance of the field drainage systems, butfeel that the maintenance of main drains is theresponsibility of the government.

Support a Farmer's Initiative in Subsurface Drainage

The ultimate goal of conducting research or developing improved technologies is that the findings shouldreach the farmers and that they should be able to adopt them in their fields. By going through the successstories of Konanki and Uppugunduru published in the news papers, seven farmers of Doppalapudi village inPonnur mandal of Guntur district approached the Indo-Dutch Network Project in May 2002 and sought theassistance to reclaim about 5 ha of land of salt-affect land. The situation was so severe (yields from 1.0 to1.2 t/ha) that the farmers were not willing to harvest the crop as it was not economical to do that. Thefarmers request technical assistance and expressed their willingness to bear the entire expenditure.

After carrying out pre-drainage investigations, an interceptor open drainage system was proposed. The costof construction of the drainage system and the expenditure incurred for the maintenance of the systems bythe farmers was worked out to be Rs. 3,600 per ha. With supervision of the IDNP project staff, the drainagesystem was installed by the farmers. After installation, the farmers took every care in maintaining the systemproperly. The saline seepage water from the uplands was intercepted effectively and disposed safely intothe natural drain. As a result, crop has established very well in almost all the fields and a remarkable increasein the yields of paddy was obtained, the average yield increased from 4.0 to 5.2 t/ha.

Drainage Protects I r r igat ion Investments

International Institute for Land Reclamation and Improvement / ILRI

irrigation investments drainage protects - wur · drainage protects irrigation investments. 2 cssri...

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