UNIT 1 INTRODUCTION TO IRRIGATION ENGINEERING

Structure 1.1 Introduction Objectives 1.2 Need for Irrigation 1.2.1 Growth of Population and Consequent Strategy 1.2.2 Historical Background 1.2.3 Planning of Irrigation Projects: Inputs 1.2.4 History of Development of Irrigation in 1.3 Advantages and Disadvantages of Irrigation 1.3.1 Environmental Effects 1.3.2 Environmental Issues -Environmental Impact Assessment (EIA) 1.3.3 Sustainable Development 1.4 Summary 1.5 Key Words 1.6 Answers to SAQs

1.1 INTRODUCTION This unit seeks to introduce to you the complexities of irrigation project planning. Objectives After study@g this mlit you should be able to: know as to why irrigation is required, understand the meaning and importance of "Masterplan'; know the history of development of irrigation, understand the impact of irrigation on environment, and get aquainted with the concept of sustainable development.

1.2 NEED FOR IRRIGATION

Food is one of the basic essentials to sustain life. But, growing food needs'water as an Input which is not always and everywhere available in required quantities. Therefore, iirtificial application of water to plants, namely irrigation hecomes necessary. 1.2.1 Growth of Population and Consequent'Strategy You may recall from your earlier studies that India is the extension of one of the oldest civilizations: India of today is at the cross roads due to the exploding population. Today, to sustain development and to progress further, it requires an Herculean effort. The result5 of 1992 census reveal that during the decade of the '80s the average annual growth in population has been 2.11%.Do yoa know that the rate of population growth is not uniform all over the country, and it varies from 4.50%in Nagaland to 1.31%in ? In other words, in absolute terms we were 238 millions in 1901 (undivided India) and now we are 875 millions in 1992 (Table T.1). Table 1.1: Total Population of Indla (In millions) Year 1901 1961 1971 1981 1991 1997* Population 238 43 9 538 683 853 985

The density of population has risen from 216 persons per sq km in 1981 to 267 per sq km in 1991. As you can see in your daily life such a growth has led to the increasing soil - PW - Water pressure on the basic life support systems of land, water, atmosphere, flora, and fauna. R-Inw* DO you how that there is a need to support nearly 2056 of the world's farm animal population that lives in India, and also forests have been dwindling and hardly 23% of the geographic area consfitutes this component? In this context, imgation development has to take place with the following aims: i) Physical access to food, at economical price, for all people at all times -&led Food Security [FAO's resolution on Food Security Act, 1985 of the USA iS an example of legal framework for sustainable use of land and water], and ii) Access to balhced die6 and safe drinking water called Nutrition Security. L The future requirement for Indian irrigation is that we have to develop the limiJed wakr resources at a rate that :-mintaim a "sustainable development". This assumes equity, efficient economic systein, ecological harmony and a stable social system. Knowing that there are many interlinked facets of water resources development, the concept of conservation of land (erosion) and water, intense cultivation, recycling of waste water, and making of a better use of the already created potentials by employing modern water management methods, are to be linked appropriately. Also, experts favour reorientfag the development from macro-system to micro-system, and free surface flow system to pipe (pressure) system. There is basically a need to conserve water, and to increase irrigatib efficiency, and hence, the stress on "sustaining the development".

IBox 1.1 What is Sustainable Development ? t It is the development that meets the need of the present without' compromising the life of the future generation. 1.2.2 Historical Background Records regarding use of irrigation extend back to 3000 B .C. India's early irrigation history ranks with that of Egypt and China; and especially in the past 100 years hdia ha& constructed some of the most magnificent irrigation works to be found in the world.

Indian enterprises with the accompaying thoroughnev with which each detail is , elaborated, and the wonderful performance of all the irrigation structyres bas been highlighted by Wilson (1890). Yo may be aware that the modem development of irrigation has not'oIlly freed 1f;dh !I fro!I the scourge of fearful famines, but also has ushered in confidence and self sufficiency on the food front of the country. Table 1.2 :Food Pductlon Periud I'

'F%e Plan (1951) 52:O I Five Year Plan (195 1 - 1956) II Five Year Plan (1956 - 1961) EI mve Year Plan (196 1 - 1966) Annud Plans ( 1966 - 1969) IV Five Yea! Plan (1969 - 1974) V Five Year Plan (1974 - 1978) . Annual Plan (1978 - 1980) 131.0 1 VI Five Year Plan (1 983- 1985) 152.3 VII Five Year Plan (1985 - 1990) 152.0 1987 - 88 (drought year) 140.0 1988 - 89 169.9 ' 1989-90 170.63 1990-91 ' + a 1?7.q~j . I* 1991,- 92 . , 167.00 ,. , India has done well in most years and could have even exported foodgrdns. To achieve lnt~oductionto nutritional sufficiency, the real stumbling block is the fast rate of growth of population lrllg~tionEngineering which outpaces the increases in agricultural production (Table 1.2). This competitive race continues and India requires a carefully planned strategy for development within this scenario. The art of irrigation management has to be based on past experience and skills employed. For this purpose we must have recorded evidences of the past experiences of eminent engineers. Irrigation comprises a vast field of knowledge. It is a fascinating field since it provides service to the community composed of several individuals having different purposes, different aspirations, different attainments, varying status in life (engineers, agronomists, economists, sociologists, farmers, head enders, tail enders, farm labourers etc.). In short, it is a field which caters to a multitude of people from different cross-sections involving five different aspects, viz., planning, design, construction, management and administration.

BOX1.2 a) What Is Irrigation? Irrigation is the application of water artificially to the soil for the purpose of food production. Thus, the water supplied supplements the water available from rainfall and other sources such as soil moisture. b) Why irrigation? The increase in demand for food requires large area to be brought under cultivation and going in for more intense growing. In other words, extensive and intensive aspects of development have to be addressed to. But, the required quantity of water at the appropriate time may not be usually available in nature; and rainwater is ill distributed both spatially and temporally. Hence, water is to be supplied according to the requirement of crops. ,

Complexlty of Irrigation Planning Irrigation projects are complex agricultural development enterprises which require the distribution of controlled quantities of water to suitable areas of land together with a large %umber of essential complementary inputs to Allow as well as increase crpp production. Successful irrigation planning, development and management include the establishment of firm objectives, direction of planning activities, operation and management of various components (Figure 1.1).

IIrr~gut~onMethods

8 Flgum 1.1; A Schematic Magrun Depleting Orgmlsstlon, Opemtlon md Maintenance Asp& d Idgation Phnning Soil Plant Water - B0$1.3 , , Relatiomhip in Irdgatlon The number of villages in India is 507000 with a nualpopulation *. of 631.22 million as per 1991 census.

The money invested in industrial development provides a higher direct ieturi~~than investments in irrigation (How and why?). Then why should we invest in irrigation'? The prime objectives of irrigation are to provide the basis for economic developil~ei~tand to eliminate hunger and poverty. Full realisation of the benefits from modem irrigation farming depends on the provision of a wide range of services.

Year Percentage -- 1901 1947 1971 1981 1991

100

90 80 70 60 - 50 40 30 20

10 10 17.3 19.9 23.43 2 hC% 0 u u u U u

U = Estimated uhnpopulation Figure 12: VPliaSion of Rural Population over Past 90 Years 'Experience has shown that industrial development does not take place until a nation can provide food, cloth, shelter and water to its pTople, these being the basic needs. Can you imagine that a high proportion of the nation's population lives in rural areas (Figure 1.2) and a major portion of the total national productive effDrt is spent 011 agriculture? Increased agricultural production, therefbre, means much to us, but achieving a substantial increase in agricultural production is not an easy task (Table 1.3). In terms of national gains, increased food production means: i) Insurance against drought and famine. ii) Saving of substantial amounts of scarce foreign exchange and avoidance of import of food. In other words it implies self sufficiency. iii) A higher level of nutrition for the entire population. iv) Exporting of food grains resulting in increased national income, which thereby generates confidence in people. Table 1.3: Projection of Future Food Requirement for Projected Population - - - Year Food Population (A. D.) (million tonne) (million) 2000 250 1000 2010 300 1200 2025 375 2050 460 Irrigation 1s an age old art, in fact as old as civilisauon itself. Adherence to tradition is lotrod~cti~nto prevalent due to high ~~alattachment. Thus, the introduction of new techniques in irrigation Engineering ' the methods of food production is a difficult proposition (Refer Box 1.4 for a contrasting picture). Weshave the tendency to resist any change initially, until we are convinced about the new changes. Thus, the development of new agricultural areas is often more protnising than trying other methods of increasing production of food or fibres. By the introduction of irrigation to new areas, exceptional opportunities are generated for introducing latest equipment. However, maximum agriculturalproduction (Table 1.3) cannot be achieved without adopting modem techniques and services. The introduction of improved irrigation practices will provide higher yield and better liviog conditions even to the farplers who are addicted to century old practices. Also, the size of the land holding matters (Tables 1.4 and 1.5) as regards the methods and techniques to be used. ' In addition to providing accelerated growth and stability at Ifational level, even at local and regional levels irrigation provides relief from shortage of food, and takes care of other social interests. * Construction of storage reservoirs at critical locations (even if it is at a small-scale development level) reduces the cost of water if the project is used for multi-purpose objectives. Table 1.4: Average Size of Land Hoiding (ha) in some Selected

Box 1.4 Picture of a modern enterprising farmer Let us assume a farmer possesses a large piece of land, say, 2000 ha in areq. Managing such a vast area requires a computer and a dish antenna combination to use satellite data, as well as obtain the following,information: i) prospects for rain, and ii) business update such as the market prices of materials, and export opportunities. Moreover, the farmer has to use a walkie-talkie for radioing instructions regarding operation and movement of machines to the workers in the field. He also needs a workshop to repair farm equipment, such as, chemical applicators, machine combinations, farm tools and implements; autowagons to drive with the tractor-harvesting combination to collect the harvested crop (these combinations can harvest an area as much as 50 ha in a day), and to load it onto the trucks for transpotting the material to the market; and bins and silos for storing the harvested material whenever necessary. This is the profile of the typical outfit required by a successful U.S.farmer. Can we, in India, adopt such a developed set-up for our farmer? In this regard consider the phad system of (discussed elsewhere); it has also to be noted that the average size of holdings is very small in India (Tables 1.4 and 1.5). Table 1.5: Operatlonal Land Holdings by Irrigation in India (Status 1985 - 86)

Classifleation Class Total Number Irrigated Ares Number of (in 000) (M ha) Hddi (inmy

76 1

Medium 7.5 to 10 657 & 10 ha to > 4.0 ha) 5.0 to 7.5 1468 4.0 to 5.0 1269 10.360 . 3394 3394 Semi medium 3.0 to 4.0 (< 4.0 ha to > 2.0 ha) 2.0 to 3.0 7684 9.684 5593 Marginal 1.0 to 2.0 8414 (< 2.0 ha to > 0.2 ha) 0.2 to 0.5 16034 8.062 7684 I 24448 Total 40.462 M ha * 41880 * Irrigated Area * Tpe figures are not merely the sum of the figures given above in the respective columns. These figures give idea of total imgated area and total number of holdings. Note: Foodgrains production may be taken as 25tonnes /ha (varying from 1.5 to 3.5 tonnesh) in imgated area, whereas it is about 0.50 tma in dry-land agricultural areas.

1.23 Planning of Irrigation Projects : Inputs Assuming a broad-based need for irrigation, it is, however, essential to answer a few crucial searching questions in order to prepare a ground for appropriate planning of a project when huge investments are involved (Table 1.6). One may summarise these questions as given below: i) Why develop an irrigated agriculture? ii) What crops are to beJshould be pown (Is it vegetables, maize, paddy, citrus, cotton, tobacco and groundnut etc.?)? iii) How much water will be required? iv) When and how much water to apply to a given crop? v) How to apply this water? vi) What will be the source of required water (groundwater and /or surface water - and what should be the mix?)? vii) How will it be distributed over the land? viii) In what way is it to be applied to the field? ix) What complimentaty inputs are required? Figures 1.3 and 1.4 bring out the various components needed for the development of, irrigation projects. Table 1.6: Fiaancial Outlay in Crores of' Rupees for Irrigation Projects (Government Outlays only)

Source :statistics Directorate, Central Water Commission, March 1994. * Figures likely to undergo changes. O This includes the expenditure of states and other institutions, on minor irrigation while expenditure on command area development is not included.

Orvolqpmrnt ot Plan lmgotion Wotrr far 1mgo6on ~rojectt Rcq UI re me nts

Figure 131 Developmet ols Conceptual PI- lor Imigdlon Projects It is highly desirable that, before most of any country's water resources are developed, a comprehensive national policy be established to provide an orderly development and to reduce th-uent conflict between individual (state) users. Integrated river basin . Soil -Rant - Water development can provide a strong rational basis for optimal utilisation of water. Relationship in Irrigation

EZigre 1.4: Management of Imgation P~.ojects

SAQ 2 I aj Define the fbllowing:

1) Master plan. cornpreh~;~slvrplainmg. mcl InteFr lr: <: dp? r .

SAQ 3

Prepare a summary of the matter presenl~:din. '*,\:i;'ir!i:?nr;i !li;7fr:!' I):!!:: f.! 1 ~::,T ,::. Indin, 1987."

Climate is probably the %lostimportant factor in crop production. Measuring the parameters that define a ciirnate is very inqsrtant, as they play an important role in planning process (Table 1.7). Clirnate is an important factor for soil forming processes. Arid and semi-arid zones of the world are characterised by high temperatures, low precipitation, relatively strong winds and high evaporation. Such a situation too provides an extensive choice of crops, but requires irrigation with very little benefit from precipitation. Climatic data most commonly measured throughout the world are daily init~imuniand maximum temperatures and daily precipitation. Climate remains fairly stable within the tropics, whereas outside the tropical climate, due to a twice-a-year swing of the sun across the equator, it is seasonal. The swing of the sun has the effect of shifting the belts of high pressure. When land becomes heated during summer months the air above ten& to rise and surface winds blow h to take its place. This takes place everyday in coastal areas. This is better seen on a larger scale as "the Monsoon", which blows inwards over the Indian subcontinent during summer, and less strongly outwards during winter. . BOX1.5 + Introdaction to Irrigation Eagbeedug What is climate? Climate is defmed as the average conditions of a place witb regard to temperature, precipitation, wind, evaporation, humidity and other atmospheric phenomena. What is weather? Weather on the other hand is day to day climate. 'What is arldlty index? Precipitation - Evapotranspiration = IA (index for aridity) (Here precipitation and evapotranspiration are in cm of water) For arid zone, IA < - 40; For semi arid zone, IA < - 20 to - 40.

~adle1.7: Importance of Measurement of Climatic Parameters

2) Precipitation supplies, Knowledge of these 3) Wind for the determination

4) expected 4) Evaporation consumption of water.

";4Q 4 I ) Cc\llecr tllr relevant information regarding the measuring devices for the parametelk mdic: d in Table 1.7. L~stthe title and number ot the codes and St:lr~J;rrJspublished by the Beaurau of Indian Standards (BIS) dealing with Il1zsc. Plot rile 1 ari&rion(11 ahwe parameters for your home tohtor one-year period. i !bran ti]? anthmet~cmean, p, and standard deviation, a, and . coefticient 01 variation. C,. They are defined as tollows:

1 Arithmeticmean: f=- X, N ,=I

Stzndard deviation. o~ , = tN- 1) . (1.2)

Water as we how is necessary to a11 forms of life including plant life. Precipitation is the firimary source of water whether it be surface water or subsurface water. A successful irtigated agriculture can exist only by finding, developing and maintaining suitable water 9s pplies. Gauging of stream flows provide basic information for surface water supply studies. Such stream flow information is essential for deciding upon the required storage. Periodic or annud flow may indicate the need tb supplement diuect diversion. The probable occurrence, in successive years, of low flows in a river indicates the need for sufficient storage to provide water for several growing seasons. Similarly, the extent &" ground water supplies and the feasibility of their recovery requires investigations (gravimetric, electrical logging, seismic or similar surveys).

Boxl.6 Gauglng (Measurements) :Surface water measurement can be carried out using the following devices: i) Current meter, ii) Weirs and flumes (for small streams), iii) Moving boat method, and iv) Ultra- viole$ray techniques. .. SAQ 5 a) Expldinmoving boat method and ultra violet ray tecmque of me:lsurincr flow in a stream. - b) List the B.1.S Codes for measuring the flows in stream and study the sane and compare.

Land levelling can be done ushi laser controlled land levelling equipment.Topographic map with contours at close interval (Figure 1.5) is required for computing earth removing requitements for purposes of land grading, or choosing suitable surface irrigation systems, e.g., land with steep slope is suitable for sprinkler irrigation (Table 1.8). Inegular shaped field is very difficult to manage for cultivation, and hence, individual rectangular shaped field is taken as an ideal situation. Further, proper slopes are also required for controlling surface water flow. Initial aerial photographs will reveal whether the given topography of an area is suitable for irrigation or not. Table 1.8: Land Slopes for Dltrerent Metbods of Idgation

SAQ 6 i) How do you get an aerial photograph'? ii) Write a note on remote sensing technique and its applications in irrigation. iii) How could the flow volume be measured in pipe water distributicm rletwork ~ the field? iv) What devices could be used for measuring flow in a field channel'? Soil serves to support the growing plant and is the medium through which plants obtam nutripnts and water, A knowledge of the soil characteristics, texture, structure, consistency and depth is necessary, for proper soil and water management. The ideal agricultural soil is a combination of sand, silt and clay so that enough water is held (stored) in soil for the use of plant. The presence of salt in excess quantity in ground affects the growth of the crop and the yield. To avoid injury to crop and to prevent accumulation of salts in soils, to allow the planting of crops in time and to reclaim the arable low lying area drainage is very essential. You will be reading more details about these aspects in the subsequent Units. I In addition to these, some of the other essential information are 1 i) best adopted crop variety, 1 - . ii) potentialcroppests, iii) availability from authentic source of quality seed, fertilizers and pesticides, 4 iv) hobable yield of the crop and expected price, v) local production methods and costs, vi) availability of transportation facilities and farm machinery, 1 i vii) labo~and animal power, I viii) cost of labour, financial support and prevailing interest rates, I ix) land texture details, and I x) availability of construction materials and equipments. Figure 1.3 shows the various components of development of irrigation plans. 1.2.4 ktory of Development of Irrigation in India Water resources have been a decisive factor in the growth and development of human civilisations, throughout history. As agriculture developed and become the mainstay of &he economic life of people, they migrated to river valleys in search of fertility of soil, congenial agro-climate adsources of water which they oould manipulate for irrigational and related requirements. These rivers played a key role in the life and living of those people, and consequently r civilisations. For example, Egyptian (along Nile River), Mesopotanian (Euphrates), Chinese (Huang-Ho river) civilisations flourisbed during 3000 B C to 1700 B C, and agriculture was the basic avocation.

Box 1.7 After independence nearly 640 reservoirs, and 20000 km of new canals were developed by 1981. Tamilnadu itself has developed 32 major and medium projects, and about 289000 ha-area has been provided irrigation during five year plans. Definitions of Major, Medium and Minor Projects Eatlier the classification of jectswas done, based on the capital outlay, as major, medium &minor projects. Classification of Irrigation projects in India based on the criterion laid in 1st Five Year Plan, was done in 1950-51: Major, costing > Rs 5 x lo7; Medium, costing between < 5 x lo7 - > 1 x lo6; Minor, costing < 1 x-10%But in 1978 it was reviewed and modified by National PlanniElgComrnission based on the cultivated area. However, in 1987 in view of the change in monetary value due to inflation,'the classification was refined as follows: Major > 1OmO ha CCA, Mediu~2000 ha < CCA < 10000 ha, and Minor < 2000 ha. Note :CCA : Culturable Command Area.

Development of irrigation can be studied for better understanding over the following periods : Sdl - Plant Water i) Ancient Indian River Valley Civilisation (3200 BC - 320 BC). Relntiomhlp m Inigstioo ii) Medieval and Modem India (320 BC - 1947 AD). iii) Water Resources Development in contemporary India after 1947. The origin irrigation in India is buried in the hoary past, and we have no way of ascertaining at what period of time organised irrigation came to be practised by various communities, kingdoms (big and small), which dotted this vast subcontinent in the early centuries. It is believed that irrigation was practised extensively in the Punjab and Sind in the Indus Valley in the north, and the Cauvery delta in the south; and this practice compared favourably with the then contemporary irrigation practices in Nile Delta in Egypt and the Euphrates and l3gres Valleys in Mesopotamia in the Middle East. Excavations in Mohanjodaro and Harappa have confirmed the existence of extensive irrigation systems in the Ind $ Valley. In fact, the political and economic power of the Harappans is known to have+b een based on their successfu! agriculture and vast stores of grains. P This civilisation disappeared due to the supposed invasion by the Aryans. However, the other reasons quoted are indiscriminate irrigation, migration of rivers (for example, river Kosi has migrated by nearly 100 km over 100 years), floods, and rising of salinity of the surface soil. In fact, the major cause attributed for the destruction of Mohanjodard civilization is the repeated occurrences of high floods. Indus river is an unpredictable, immensely destructive river. Indus carries down 207 x 109 m3 in a year. Its peak can be 11327 m3 s-', and the lowest flow 566.3 m3 s-'. Finally, the supposed foreign invasion sealed the fate of this civilisation. Study of archaeology reveals that Chalcolithic and Megalithic people were the earliest to build reservoirs in prehistoric . Reservoir near Inamgaon (near Puile) has been estimated to have been built during 1500 BC.

1 Box 1.8 Q@ A Foggara or Qanat is a tunnel which carries water for some distance underground to the place where it is to be used. The length of tunnels could be more than 16 krn. The uppermost catch pit is known as the "mother well" or "Mader Chah". Other than dug wells the water supplied for irrigation was from ground water source through horizontal wells called "Qanats" (Figure 1.6) in the south western Ash and Norih Africa (Afghanistan to Morocco). A mild slobing channel leads the water by gravity from beneath the water tablk at its upper end to the ground surface outlet and the downstream injgation canal. Vertical shafts were dug at very close intervals. This practice dates back to 1000 BC. Some of the qanats are as long as 29 km with wells of 96 in depth with 966 shafts. Iran possesses the maximum number of qanats and some of them can yield very huge quantities of water (100000 Vhour). These are also known as Karef (in Pakistan) and as Foggara. Flow rivers do flow right across a given desert belt. These are called exotic rivers as they originate outside the &sea zone, e.g., Nile, Indus, Tigris, Euphrates and Oxus (Amu Darya), Colorado River, Snake, Rio Grande River, Orange and Vaal rivers of South Africa, H Wang Ho River, Volga, Ural, Don. Sur Darya, Niger etc. Some of those streams that come into a desert area usually dry up before getting far. In Atacama desert, for example, hundreds of small streams flow down from the Andes, but none of them penetrate more than a few kilometre into the arid zone. Exercise i) Trace the history of migration of river Kosi. Why is it called "River of Sorrow"? ii) Why did "Saraswati" disappear from '? Introduction to Irrigation Engineering

Figure 1.6: Vertical Cross-sdon along a Qanat (After Beaumodt) RePereqee: Ground WaCsr Hydrology, 2nd edn by D. K. Todd.

The migration of Aryans to north Indian river valleys of Ganga has been the process of initiation for the current civilisation in north and central India. History reveals that Ganga Valley has been the melting pot of socio-religious and political practices that . shaped India. RigVeda (1100 BC) refers to the agricultural processes, rice cultivation, use of iron ploughs and related operations. The very development of cities, such as, Ayodhya, Varanasi, Patiliputra reveals the three major roles of rivers in Indian economy viz., agrarian, urban, mercantile. At this stage the people started worshipping the rivers and treated them with reverence, There is evidence that during the Vedic period (400 BC) people used to irrigate their crops with dug wells or with inundated water. Ganga valley was the cradle for several mighty dynasties such as Maurya (about 320 BC) mainly due to life supporting fertile land and abundant water resources. The definitive evidence of the existence of canals and tanks is found in the Magadh region of Bihar. At the foot of Girnar mountains a sweet water lake - "Sudarshan Lake" - was built. Chandragupta Maurya (322-298 BC) constructed this lake, and canals were executed during Ashoka the great. The dam collapsed due to a very heavy rainfall in 150 AD. The repair works were carried out during the reign of king Mahakshatrapa Rudradaman I in 151 AD. Junagadh inscription provides a complete history of the earlier reservoir and the description given reveals the details about the cyclonic destruction that overtook it. The d'un after restoration again collapsed in 455 AD, during Skanda Gupta's period. Famous Arthnshastra by Kautilya (Chanakya) reveals the levying of taxes based on the proportion of rainfall received by a given cultivated area. Water harvesting system aspects are also indicated in this book.

Box 1.9 The device for the measurement of rainfall (Varshamana) used during Chanakya's Period : Volume = 51 1 in3 (8373 cm3), Surface area = 254.3 sq. inches (1640.64 cm2 ). 16 Dronas = 32 inches of rain (812.8 mrn of rain) . 1 Drona = 50.8 mrn of rain Ref: History of Hydrology by Biswas, A.K., Am. Elsevier N.Y. 1970. pp.76

It was the pinnacle of development in the management of wate source and practice of agriculture for that period. All the so called modern concept ?such as introduction of new crops to suit the agroclimatic conditions, repair and maintenance of canal systems, export of food products, and fallow land cultivation were practised with success. Such a prosperous scenario later got reduced to a condition that was next to nil. In the Chaulukyan period (942 AD - 1304 AD) sever2 types of reservoirs, viz, Sara (lake), Vapi (step wells), Kypa (well), Tadaga, tataka in swkrit, (pond or tank) were in aistence. Vapis are classified as Nanda (3 storied with one entrance), Bhadra (6 storied and two entr'ances), Jaya (9 storied, three entrances).,vijaya (12 storied and four soil - Plant -Water entrances). Vav (one more type of a step well prevalent in ) may vary from one Relationship in Irrigation storey (eka Kuta) to seven stories (Saptakuta). Vavs listed in Box 1.10 heldng to the Nanda type. These Vavs are decorated with beautiful paintings of gods and goddesses on the roof, No wells can be compared with these beautiful works either structurally or in respect of decoration of these step wells.

Box 1.10 Stepped Well The earliest known step well in Gujarat is the Rani Vav step well (constructed by Udayamati, Queen of King Bhimadeva I, 1022 - 1063 AD). Other lcnown step wells are: Madhav Vav (14U1 century AD), Adalaj Vav (irrigation shaft is 518.2 cm dia, 65.53 rnm length, nearly 16.76 m deep, 1499 AD), Dada Hari's Vav (1499 AD). Vav is also lcnown as Vavadi in Gujarat. > Siglar wells ark found in , e.g., Musikina Bavi (where three flights of steps lead to the water covered by a structure built in Jakanacharya's style). There are several such wells built during Chalukya period at Lakkundi having projecting small canopied niches on one side. Irrigation was later extended during the later Hindu, Muslim, and British periods. Any development in the country is possible only if there is a stable political system. In particular, in Northern India for about six centuries since the 9th century there were frequent foreign incursions and internal disturbances. Inspite of this situation agriculture remained the backbone of Indian economy. Dug wells with water lifting devices, ' supporting the practice of agriculture, were developed. In the 14th century two reservoirs and a very elaborate canal network were constructed by Tughluq rulers in the Gangetic plains and water tax was levied.

Box 1.11 Some Examples of Inter-Basin Transfer of Water through Canals Karnool, Cuddappa (1860 - 1870) Periyar Vaigai (1896) Rajasthan Canal (Indira Gandhi Nahar) Pararnbikulam Aliayar 'Sarada Sahayak Ramganga - Ganga Beas - Sutlej Nagarjunasagar Right Bank Canal Tungabhadra High Level Canals Telguganga Canal Sardar Sarovar Canal

Activity 1.1: Write a note on inter-basin transfer proposals such as : i) Ganga Cauvery Li ii) Garland Canal Scheme iii) Niharika Sarovar Nigam iv) National Pipe Line Water Grid Suggested Reference :Proceedings of the 2nd National Water Convention 17-19, Jan, 1991, National Water Development Agency, New Delhi. In arid and semi-arid areas of North India it was easy to divert water, through canals, from perennial rivers like Ganga and Indus during floods to the fields. These canals are called inundation canals. Table 1.9: important Canal Systems Introduction to Irrigation Engineering

Betwa Canal 1881 - 1886 Eastern Canal 1953 B hakra 1875 - 1879 B ikaner Canal - Sarada Canal 1915 - 1927 Sone Canal (Col. C.H. Dickens) 1869 - 1875 Tribeni Canal 1897 - 1914 Kosi Canal (2481 canal structures) 1955 - 1971 Chambal System 1960 - 1970 Mu yarakshi 1946 - 1956 Damodar Canal 1935 Tandula Canal 1925 Mahanadi Canal 1927 Godavari Delta Canals ICrishna'Delta Canal System 1855 - 1898 Cauvery Mettur 1934 Perivar Svstem of Canals 1897 Krishnaraja Sagar Canals 1930 Kuttanad 1956 Lower Bhavani 1956 Ghataprabha Canals 1958 - 1959 Nira Canals 1906 - 1938 Martand Canal 1905 1)udi Canal 1936

Zainger Canal 1931 ' I Mandi Canal 1 1936 . I

Lolkuhl Canal 1903 A Rariabir Canal 1905 Pratap Canal 1904 Uj h Canal 1923 Basantar Canal 1917 Note: In Hirnachal Pradesh: Channels with a supply of water are called Kuhls. Seasonal supply canals are called Katds. Ref: Report of Inigation Commission, 1972. In South India due to insufficient fertility of land and poor agroclimate, water resources development was badly needed to sustain agriculture. Besides, in South India where there are no perennial rivers and areas receive scanty ininfall, water was collected in tanks by

I Soil - Plant - Water . tapping the streams for domestic and agricultural purposes. At places with higher ground Relatiowhlp in Irrigation . water table lift irrigation wells were commonly used. Farmers took to irrigation by talk5 and wells to overcome the vagaries of monsoon. Anicuts (type of weir) were constructed. Few dams such as at Madag lake and at Dhebar lake were constructed during 15th and 16th centuries. Similarly, Udai Sagar was constructed during the 17th century in Rajasthan, and Jaisrnand lake in 1730 AD. There are references in Tamil Sangam literature (before several centuries of Christian era upto 300 BC) to show that rainfed tanks existed and irrigation canals were dug ill the Cauvery delta. hefarmers dug wells to tap ground water. In many areas lo'' -a1 c-1 lieftains with the active cooperation of the beneficiaries have created systems of si~lallt;u~ks over a long period of time. Very old structures built across several streams of Tainil Nddu over rocky base like the Kodaimelazhagan and Nadiunni anicuts in Tambraparani systein, Kodiyeri and Kalingarayan anicuts of Bhavani system and so on are still i'uiictioilirrg well. Production based tax reformation was practised; and there were attempts to m~lodicythe revenue structure and the regulations for owning land. But no commensurate efiort was made either in extending or developing irrigatioii facilities. Gradually productiou declined and the rulers, hence, resorted to excessive taxation. To.maintain the revenue collection, repressive measures were adopted. Thus, dissatisfied farniers led to the decline of Mughal empire which became vulnerable to the traders from Eumpean conlpauies. This adverse effect of the neglect of irrigation development and appropriate water resources management took a heavy toll on the powerful Mughal empire. The arrival of the British re-established the political stability which lasted tor neaily 200 years. In the name of trade the French, the Dutch, the Portugese and the British dominated over the Indians either by exploiting their weakness (viz., lack of unity and selfishness) or by capturing power by force. Tank irrigation is prominent in the semi-arid part of western and central India. viz., ~aja'sthanand Malwa and entire southern India. Ti11 the initiation of five year plans m India, tank irrigation was practised with emphasis. There was consistent effort for kuilding up water works over many centuries to hold the runoff water and llarvest for the benefit of the citizens. Royal patronage and peoples participation made the system a. success and sustainable. Development of water resources seems to combine a sense of fulfilment of basic needs, love for nature and devotion to religion, God and sentiments. Kings constructed tanks and temples and donated in the name of their parents or children. Beginning of the destruction started during 1636 AD following series of Mysore wars. Purnaiya, Dew an of Mysore (1800 - 1812 AD) put in special efforts to restore reservoirs in Karnataka where there came into existence 14803 tanks and 8562 Kuntes in 1806 AD. Tanks are concentrated in the Telangana region of Andhra Pradesh, old Mysore region of Karnatakaisee Box 1.13) and in the eastern parts of Tarnilnadu. Cholavarani and Redhills tanks (during Cholas or Pallavan time) raised and strengthened during 1872. Raja Raja I11 (1216 AD) initiated the excavations for Narayana Putteri at Puttur and the largesl irrigation tank viz, Chembarambakkam tank (26 km west of Chennai city; 88 ~111" 6192 ha) .in Chengleput district. There are several tanks such as Mahendravadi (600 - 639 AD) by Mahendravarma and Kairerpauk (one of the largest tanks) in 846 - 869 AD by Nandivarman in Palar basin believed to hve been constfucted by the Pallavan dynasty and Raja Singamangalam. Big tanks of Ramanathapuram perhaps buiIt by Pandyan in Ramanathapuram area are serving well even now. The period of 937 A.D to 1336 AD can be called the golden age of ranks in south India. ' Note: Kere, Kunte, Kola, Talab, Kalyani connote different sizes of tanks. Kupa;Baavi are local terms for wells. The inscription of Porumamilla of 1369 AD in Cuddappah district is like a handbook on the methodology of construction of tanks. Bukka I1 and Jala Sutrada Singaya Bhatta are credited with having diverted river water. Inundation canals (Vellakkal) were popular during the Pallava period. Sahsra Lingam, a big reservoir was constructed by the Chalukya Queen, Vaayamati . The arrangement of stone sluice gates shows a high degree of technical skill of those days. Chalukyas created a separate water works departiilent (Vari-Griha-Karana). Chola Kings also did not neglect the tank construction. Krishisukti of Parasara describes the krishi (farming, agriculture) as early as 1000 AD. Similarly, books like Lokqpakara (1025 AD), and Rattamata (1300 AD) provide an account of . I traditional infdrmation available about agriculture. 1 Box 1.12 Introduction to Irrigation Engineering In ~ovemblr,1858 AD, one of the most severe floods, but of upown magnitude, occurred. Similarly, in July 1896 (15862 m3 s- ); November, 1906; July, 1911; November, 1920; in 1924 at Mettur (12900 m3 s-' ), in 1961; and in 1977: and in 1991 floods have passed over the Grand Anicut on Cauvery.

Tamil Nadu had 22 reservoirs, 30 canal projects, 33086 tanks and 728092 wells to irrigate 11 to 12 million acres (4.45 to 4.85 million ha) of land during British period (1943 - 44). I Till the first half of 19th century, irrigation in the areas of Andhra Pradesh was practised thiough large number of tanks and wells. Construction, by Sir Arthur Cotton, of the Godavari and Krishna anicuts in 1850s heralded a new era of large scale irrigation development through anicuts. Structures built during this period were run-of-the-river I schemes and did not involve large scale impounding of river waters behindstorage dams (barrages). Some of the irrigation projects developed between 1900 AD to 1951 AD in Andhra ~radeshare given in Table 1.lo. I Table 1.10 :Development Irrigation Projects In A.P.

Nizamsagar (Manjira) 1935 111290

Lakhnawnrm (Salivagu) , N.A 2873 - * N.A: Not available. Rayalaseema area has been irrigated for centuries by 17 canals laid through the rocky banks of Tungabhadra up to the fields. These canals helped in sustaining water inlhe wells as well. But, by the middle of 16th century this system could not be sustained. Almost till 1863, no development took place. However, a new canal, Karnool- Cuddapaha Canal was constructed by a private company, viz, The MadrasJrrigation Company. This canal was designed for inland navigation and for irrigation also with a designed capacity of 45 m3s-'. However, navigation was not successful due to poor design of the system. This system was taken over by the Government in 1882 AD. Pennar Anicut across river Pennar was constructed in 1887 AD. The deltaic canal systems were developed next: Krishna Anicut near Vijayawada and Godavary Anicut at Dowlaiswaram. The Dowlaiswaram micut (4 km long weir, 2.4 km long embankment, 3 sets of canal head works) was the longest in the world executed by Sir Aurthor Cotton, (construction period : 1847 - 1852 AD). FCrishna Anicut was replaced by Prakasarn barrage (constructed just upstream of the former). Numerous big tanks and irrigation works in the lkngabhadra region existed as far as 1369 AD during the reign of Prince Bhaskara ofthe Vijayanagar dynasty. For nearly 300 years, this river acted as a bmier against the invasion of the Muslim sultans from Delhi, but in 1565 AD Viajayanagara was ovemn and destroyed. In 1800 AD, the Nizam of Hyderabad ceded tl~earea to the soutt~of the river to East India Company. Progressive deterioration of erstwhile irrigation works in the country and occurrence of successlve famines in the closing years of 19th century made the British rulers take stock of the situation which led to the setting up of the first Famine Commission in India (1878 - 1880). In 1891 First Irrigativn Commission was set up. The second Famine Commission after the drought of 1896 .. 97 reconmended that first priority be given to works of irrigation amongst the various measures adopted for giving protection against the ill effect of drought. However, emphasis was still on digging of new tanks and the repair of existing tanks. It was only after the appointment of the First Irrigation Commission, that some ambitious construction programmes were planned in 1901. This Commission recognised the importance of the development of Tungabhadra rivet. . Soil - Plantr Water - Krishna Raja Sagar in Karnataka was completed in 1930. Later Tungabhadra Reservoir Relationship in Imgation project was jointly developed by Karnataka and Andhra Pradesh. A 20-year plan I envisaging a huge public expenditure to irrigate 2.6 million ha was drawn with a view to control, conserve and utilise water wealth of the rivers by means of storages. But. still the approach was essentially location specific and project specific. Taccavi 10x1was recommended by the Irrigation Commission, but the development between 1901 to 195 1 was only of the order of 0.18 million ha. However, as a consequence of this, several major storage works in south India and tubewell specific irrigation schemes in western UP were implemented. During this time some helpful developments also took place such as, the establishment of Thomson College of Engg, Roorkee (1850 AD), and Central Water and Power Research Station, Pune (1916 AD). At this stage some of the pioneering engineers such'as Sir A* -ther Cotton, Sir Praby Cautley, Kennedy, Lacey, Sir M.Visvesvaraya, were responsible for developing major irrigation works in Ind~a.In this period several legislative Acts were also passed (Refer Box 1.13). Similar Acts and laws were brought to apply in Bombay, Bengal, and Punjab regions. However, the organisational structure that was responsible for the operation and maintenance of these irrigation systems and the authority vested with them, various Acts and Statutes that empowered them, all vary fromstate to State. Many of the States do not l~avea comprehensive irrigation law. The traditional procedures linger on, of course greatly eroded by the local political and other pressures, water being a state subject as per Indian Constitution. Some of the good developments that took place were concentrated in south India, UP aqd Maharashtra.

Box 1.13 Madras Compulsory Labour Act, 1858 (Kudimaramath) Madras Imgation Cess Act, 1865 Northern India Canal and Drainage Act, 1873 For Punjab, UP, Hariyana, Rajasthan. Several modification - introduction of warabandi system to get fixed quota of water to individual holdings of the block under the outlet, for a fixed time. Amended in 1958 and 1965 Bengal Irrigation Act (West Bengal, Bihar), 1876 Bombay Irrigation Act (Gujarat, Maharashtra), 1879 Madras Land Encroachment Act, 1905 Tank Panchayat Regulation, 1911 Madhya Pradesh Irrigation Act (Vidharba, Marathwada Region) Mysore Irrigation Act, 1932 (Modified in 1952,1965) Madras Irrigation Voluntary Cess Act, 1942 Madras Irrigation Works (Repairs and Construchons) Act. 1043 Madras Irrigation Works (Construction and Levy Act applicable to Mallabar), 1947 Madras Irrigation Levy and Betterment Contribution Act, 1955, Travancore, Cochin higation Act, 1956 Madras Irrigation Works (Construction of Field Bothies), 1959 Mysore Imgation Act (modified earlier situations after reorganisation of States), 1965 Formation of Zilla Parishad, 1987 I

In 1882 there were about 30000 tanks (with only 4106 l&ge irrigation tanks) i.e., almost one tank per every sq mile, and 40000 small river channels in old Mysore State alone. Tank construction in Mysore State gxeatly added to the quality of life in the land (Table 1.11). Some of the famous tanks are listed in Box. 1.14. A pathetlc point to note is the. encroachment on these facilities; for example, there were nearly 40 tanks m and around Bangalore in 1940s, and now *e number has been reduced to less than 10 in 1990s. has been a pioneer state in India and as much as 47.5% of the culuvated area in tha state is irrigated which makes it the best Irrigated state of the country next tn Introduction to Punjab. The people started lifting water for their use from streams and rivers or dug wells Irrigation Engineering utilising lifting mechanism like the yickota; diversion structures (for harnessing river waters for farming) were also built long before the Christian era. Irrigation has a very ancient history in this state and in the Cauvery Delta. The Grand Anicut was originally built by the Chola kings. The kings of Chola, Pandya and Pallava dynasties have together built a large number of irrigation works. In Vaigai and Tambraparani basins even today one can see large number of anicuts, channels built by Pandya kings. The Korambus were built in the river beds to direct water to the open head channels Table 1.1 1 :Area under Canals

Source-wise Area (ha) Percentage Irrigation in Mysore (1990 AD) Canals 5624 1 11.16 Tanks 259742 51.55 Wells 60349 11.98 Other sources 127530 25.31 Total 503862 100.00

1 Box 1.14 :Some Important Tanks in Kamataka a) Moh Talab (Tonnurkere) near Srirangapatna (I lth century) across Yadavanadi (a mountain stream) is 24.38 m high, 152.4 m long, 15.24 m wide at the top and 137.16 m wide at the bottom with 2220.35 ha-m capacity, and the area irrigated is only 323.76 ha. ' b) Shantisagara or Sulekere near Channagiri, Shimoga district constructed between (1 336 - 1565 A.D) by Shantawa has a length of its bund equal to 335.28 m, with a height of 18.29 m. Water spread is 25.6 sq km, circumference of water spread is 64 ,km. It is built across Haridra river. A dam wastconstructed 56 lan d/s of this and the dam breached within 14 years and was reconstructed at the present locabon having 60.96 m length with a command area of 2832.9 ha. C) Ramasagar is located 32 km from Kolar across Palar river. This tank has been constructed during Bukkaraya's dynasty. This breached during 1751 - 1782 AD; it was called Bukkasagar. Dewan Purniaya (1 800-1 81 1 AD) restored and changed the name to Ramasagar. d) Sankey tank is named after Major Sankey, chief engineer of Mysore, 1866. e) Kanataka has been a forerunner in managing traditional water harvesting strictures like Arakere, Volakere, Devikere, Katte, Kunfe and Kola. 40000 tanks still exist as on today.

Tank irrigation in Tamil Nadu accounts for nearly 29% of the total irrigated area, being around 38335 tanks that have been built mainly during British days. ,Delta irrigation presents problems which are unique to itself as geophysical and ihydrogeologlcal aspects differ with respect to non-deltaic schemes. Habitation as well as agricultural operators are the oldest in existence. Growing of food in deltaic regions was ,'easier and, hence, resulted in higher density of population. A river before it enters into sea, due to the higher boundary resistance, splits into several distributaries and frequent inundation of surrounding areas takes place. Over several centuries due to the interaction of sea and littoral drift the delta spreads over several square kilometres. In addition to this, the mouth is subjected to tidal effect causing the salinity to intrude into the'land. This to an extent gets reduced during the, period of floods. Along the east coast of India large deltas have formed near the mouths of Mahanadi, Godavari, Krishna and Cauvery, and of course the famous Sundarbans of West Bengal. These areas are very fertile and !?dI.PS.d-W&r sustain agriculhue satisfactorily. On the other hand, on Malabar and Konkan coasts the R-hMm" land available between the Western Ghats and the sea is only a narrow strip and also , rivers carry very large volume of water during the monsoon; and hence, cc)nditions are 1 --- not conducive for the formation of deltas at the river mouths. Box 1.15 : Cauvery Delta Scheme Grand Anicut : Cauvery delta formed by the river over millenniums is a rich Pluvial tray in the shape of V(De1ta) with its base at the coast measuring 125 lan north south and its appex at the upper alicut, 160 n to the west of the coast. Total area of this triangular zone is 1000000 ha. Cauvery discharges its floods into Colleron, bordering the delta in the north. The delta is known as the granary of Tamil Nadu. The delta constitutes 40.8% of the irrigated area, through canals and rivers, of tbe whole State, and contributes 25% of rice production in the State. Cauvery and Pennar are the maim rivers flowing though the delta, and these divide and subdivide among themselves fonning as many as 36 streams. The river normally cmes a flood during the 1st week of August (during Adi month of Tamil Nadu calendar). This water would be useful in supporting crops through heavy inundation. In addition to the number of streams. several irrigation canals have been created over a long period with wide inlets and large cross sections so as to receive as high a flow during flood period as possible and to cnrry it to inundate the very large flat tract. Due to siltation in the river an uncertainty was introduced in ' regulating the flow distribution. The upper anicut is located at the junction of Cauvery and Colleron. Colleron is wider and carries a major quantity of flow during the floods. Cauvery running parallel to Colleron again branches out into Ullar which confluences back with Colleron at 27th km. In order to provide a continuous input Grand Anicut was built at Ullar head in the second century AD. This was constructed by the great Katikala Cholq of aeChola dynasty. This is one of the unique structures built on a dermeable bed when the science of building on sandy bed had not been developed. The net irrigated areas in the Cauvery-Pennar systems in the delta, at the beginning of 19th $ntury. was aound 242812 ha. In 1924, a peak flood of 12900 m /s.(before Mettur Dam was wnstructed) was recorded. (Also see Box 1.12) In 1800 AD irrigation system had deteriorated due to improper maintenance and neglected repair works. In 1804 Grand Anicut was repaired by Captain Coldwell. The silting of Cauvery continued with its bed steadily rising. In 1829 Major Sim provided four sets of river sluices at various locations in the downstream to divert water from Cauvery to Colleron. To eliminate the sediment Upper Anicut was built by Sir Aurthor Cotton in 1836 - 38. AD.

However, the vast expanse of land near Gujarat coast has lead to the formation Rann and Kutch area. Box 1.15 and Figure l.7give the details of Cauvery delta. This consists of 37 htreams with a total length of 1006 krn. There ate 1505 class "A" channels totalling to a length of 5600 kru, but the total branches put together (28376 in number) it works out to 18000 Irm. There are 22 defined major drains. Grand Anicut is at the head d the delta. The delta thought to be a major source for groundwater; for example. the extractable Water from Cauvery delta is estimated to be 764.55 million m3. 'Rwdbpendence of India's agricqture on south-west monsoon, and its vulnerability have been recognised as the two most crucial factors since the earliest times. As agriculture has always been the principal occupation of the vast majority of people, successive rulers have directed their energies to improving the lot of the farmer. Water was brought from rivers, streams and tanks to the fields in order to afford protection against the failures of -.--A ." .. . .. - ,.,. . ...a .. . . of wells dug by farmers themselves. Int~wductionto Irrigation Engineering

I t7 ~marovathj1956 A.D. A LI v Y ~attaloiBed RegulatoG 1931 A.D. I. Upper ~nycutr1136 A.D. I IB 150 Yards co linagullol)a, 1B36 A.D I \ t t Rood Oamr1925 A.D.

Grand ~nicutr.2nd Crntury t Lowrr Colloron#l836 A,O# ~nicut I---- Vrrranam Lake Figure 1.7; Schematic Sketch of Grand Anicut System - Cnuyery DeltaDevelopment Early irrigation was confined largely to impounding of rain water in tanks and providing canals from these tanks to the parched lands. Some exceptions to this type of development are the Cauvery delta canal system and also a few inundation and diversion canals from other rivers. However, these efforts were limited to irrigating only a small portion of land in the region. Irrigation in India had a boost in late 19th and early 20th century. Several old canal systems were improved, renovated, rehabilitated, and new and more complete canal systems were developed. Some of these canal systems are : i) The Godavari and Krishna Delta systems ii) The upper Ganga, Agra, Sone Canals iii) Cauvexy Mettur iv) Nizanl Sagar 11 ' V) Krishnarajasagar Dam ;I vi) Sutlej Valley Canals ' 1 vii) Sukkur Barrage 1 These schemes helped in extending irrigation over large areas. Ganga - Yarnuna Doab constituting the western part of Uttar Pradesh state contains very fertile tract of land. However, the Doab area faced intense famine in 1783 - 1784 A.D., 1803 - 1804 A.D. and 1837 - 1838 A.D. The first major Upper Ganga Canal was constructed during 1830 - 1854 AD. Its investigatio~land formulation work was done by Sir Proby T. Cautley. The total length of the canal executed (main and including branches) was 1360 km wit? a head discharge of 191.14 m3 s-'. The canal was commissioned on 7-4-1854. Upper Ganga Canal was the largest in the world. It takes off from river Ganga near Haridwar. It has two head works: at Bhimgoda and Mayapuri at Haridwar. The construction of cross drainage works on these canals were remarkable feats of the mid-19th century. Solani Aqueduct (15 spans of 15.24 m each) near Roorkee, is one of the outstanding works founded on wefls-pf 7.01 m diameter. The canal discharge has been increased from 191 m3 6' to 283.2 rn. s . The canal contains several falls; and the full supply level of canal is 1lm above the bed. Pathri (20000 kW) and Moharnmedpur Power Houses (9300 kW) are situated on these canal falls. Modernisation of the canal-has been taken up since 1979. I Soil - plant - Water Western Yamuna Canal was built during 1718 - 1748 by Mohammed Bin Shah. Other Relationship in Imgation system, such as : Upper Ganga (1830 - 1854); Lower Ganga (1870 - 1878); Eastern Yamuna (1830 - 1854); Agra Canal (1868 - 1875); and Sarada Canal (1915 - 1927) added to the irrigated area of the country. Ten medium canal systems were also developed during the same period. Water ~ancha~ats Early in the history of irrigation, most of the irrigation systems were managed by water panchayats (based on collective management concept) as in the Phad system introduced by Queen of Indore, two hundred years ago, and the Khandesh system in western Maharashtra, tank management in Tamil Nadu, Vijayanagar canal system, and systems in Bali (Indonesia) and Valencia (Spain)*. Some of these systems are still active. The colonial rule in India imposed government control on these systems. This change killed the traditional management organization of the farmerslpanchayats. Even after the attainment of political independence, the same practice viz, "government controlled system7'is still practised. The irrigation Acts of 19th century treated irrigation systems d purely as government controlled systems. The Bengal Act, North Indian Irrigation Act, the Bombay Irrigation Act did away with the collective management concept of irrigation. Pani panchayat, is one more management concept that gives an integrated scheme of management of water, land area, and cropping pattern through the ibvolvement of community in which water distribution is effected in proportion to the family size rather than the land size. *Note : This Phad system is observed to have existed in Philippines (being called Zanjaras system), in Indonesia (known as Subaks system), in Pakistan (known as Guls system), in Northern Thailand (called as Mung Fai system). In 1947, Bombay State introduced the concept of canal advisory committees (at canal level) and water Panchayat Committees (at canal inspector's beat level), etc. In 1976, Maharashtra Irrigation Act provided for water users committee (where more than 50% users have come together). Under the command area development programme of 1974, an attempt was made to promote the interest of the farmers. In 1987 the Govenlment of India introduced guidelines for farmers' participation in water management; this system can be classified as per the extent of command area shown in Box 1.16.

Box 1.16 :Extent of Command Area Definition for three tier canal supply system Canal 400 to 10000 ha Minor 40 to 400 ha Outlet c 40 ha Both the area and number of farmers I farms covered would be important for classification- of the operating system (Figure 1.8).

v) crop rototion rehedulrc and vi) crop pottrrn.

Figure 1.8: Clarrsification of Water Panchayat Systems Phad System It is basically a river diversion system. Phad connotes a group of contiguous farms (where each phad is around 50 ha in area), wherein only one crop is grown during a given irrigation season which is decided upon by an assembly of farmers during, say, April-May Herein the canal system is maintained by the irrigators themselves. An irrigators' &rum decides and informs the individual users to provide cash, or support in kind, for the maintenance of the system. The size of the system varies from country to country (in Taiwan the unit size, is 150 ha; Subaks is 41 to 800 ha : in Bali Island, Indonegia - 1072 AD, phad 20 to 200 ha). Introduction to Irrigation Engineering Each phad system usually has a weir. There are, however, a series of weirs on the given river system. The low diversion weir, called bandhara, is the control point on each phad I system. The'bandharas date back to 17th century. Each bandhara is referred to by the 1 name of the village wherein the major portion of the command area lies. The bandhara usually lies at the boundary of the village. The phad system consists of many inter-related elements as outlined below: I I i) Bandharas or low weirs constructed across the river. ii) Kalva or canals that feed the users' fields carrying water from the bandharas. The canal carrying capacity varies from 150 to 400 Us. iii) Charis or distributaries for feeding water from the Kalva to different areas of Ge phad.

5 iv) Sarang or field channel for carrying water to individual fields. I v) Sandam or escapes along the canal and charis for diverting excess water into the It drainage. I vi) Kayam Bhagayat (i.e., command area) is usually divided ink34 blocks (or phads). Now, however, the phad system is under decline. Ref: Proceedings of the 2nd National Water Convention, January 17 - 19, 1991, National Water Development Agency, pp. 32 - 35 Warabandi System Warabandi system of water distribution and management has been practised for over a century in India. The available water is distributed in proportion to the culturable

command area (CCA). In lean years the hardship due to shortage of water is shared by , everybody. Typical allowance of water is 17 lpsl100 ha. This water allowance (the share for the farmer) can be drawn proportionately by the farmers simultaneously. All distributaries operate intermittently, at intervals, through the days of the crop season. Such a rotational system is dominant in Punjab and Haryana. In this context capacity factor is defined as the ratio of the operating period to the crop period Head-end farmers would have all the distributaries operated with full discharge for 8 days at a time. The roster covers all the farmers for 168 hours. Water is allotted to individual farmers based on the culturable command area. Water distribution is from head end to tail end. Mohini Water Cooperative Society - The Mohini 'Cooperative Society was registered, in 1978, in Gujarat under Cooperative Societies Registration Act, 1961. This is located in the Kakrapar compand area. There are four water courses and two outlets commanding a total area of 500 ha. Water is charged on volumetric (consumption) basis, and is supplied accordingly. The management prepares a "wara" (i.e., for a week) programme of irrigation and water allotment and actual supply are supervised. The cropped area has gone up from 350 ha to 1000 ha. The quantum of water involved in this system for sugarcane (CCA 487 ha, cultivated is 374 ha) (@ 2 m of waterlyear) comes to 748 x 10 = 7.5 M m3. However, with the water charges being uniform for the entire period there is no incentive to save water. Water Resources Development in Independent India after 1947 The turning point that ushered in modem developments in India was 1947, when the partition of India took place. This act resulted not only in the division of irrigation systems and irrigated areas, but of the assets as well. Thus, agricultural base of India suffered a severe blow and India was left with 80 per cent of the pre-partition population while losing 31 per cent of the irrigated area which was relatively more productive providing large proportion of cereals, oil seeds and fibres. Nearly 50% of 1340 m3 s" water flowing in the canals of India fell in Pakistan. In the command area of the Indus system the ratio of irrigated land between Pakistan and India was 8.5 million ha: 2.1 million ha (80.19% to 19.81% or 4.05:l ratio). Some of the unique projects such as Sutlej Valley Project (still amongst the largest systems in the world), Sukkur Barrage across the Indus in Sind with its extensive canal system fell in the share of Pakistan. Such a reduction ~JI the major irrigation system led to an immediate impact on India's food problem. Added to this was the disruption in the production in mycountries fdllowing World War 11. Whenever there is scarcity of food in any country either due to natural calamities (such as drought, famine, pests, earthquake or flood) or due to man made hazards such as war it hurts the world economy, health of the public; and these effects persist longer in developing countries. Thus a great necessity and urgency was felt to develop the Indian economy, and, hence, the concept of Five Year Plans was given a practical shape. The thrust of First Five Yeat Plan in ,1951 was on the planned development of irrigation. At the time of independence only 22.6 million ha were under irrigation. Next three plans brought this upto to 37.5 million ha in 1969. It has been a stupendous and staggering national task to build irrigation systems in the country, now the irrigated area being of qeorder of 85 M ha (in 1992).

Note : i) Figures in bracket represent numbers of medium projects. ii) Major projects developed in the pre-Plan period were mainly in: Andhra Pradesh (I I ). Tamil Nadu (17), Uttar Pradesh (15), Madhya Pradesh (6). However, as of (1994) the maximum number of , projects are located in: Maharashtra (272), &ladhya Pradesh (165), Gujaqat and Andhra Pradesh - 28 (163 each) and Uttar Prqdah (120). There were thee aspects of developmental priorities identified in India: Intmanction to Irrigation Engineering i) Development of irrigation to secure a planned increase in the praduction of food, and not just as a measure to counter famine conditions only. ii) To base the development on a careful, selective and extensive footing. iii) Development of irrigation to be part of a comprehensive! planning for water resources development. At the time of iqdependence, India had hardly two big storage reservoirs of a capacity more than 1 km viz, Mettur Reservoir in Tamil Nadu and Krishnaraja Sagar in Karnataka. (Mettur Reservoir - volume is 2.647 kmkishnaraja Sagar - volume is 1.163 km3). Since then 28 more reservoirs of capacity larger than 1km3 have been built. The country has 1428 number of major and medium reservoirs (Table 1.12) 2731 small reservoirs. Besides there are nearly two lakh.smal1 surface water (village) tanks. The total storage in the entire country that has been developed is equal to 372.10 km3. The storage works Out to about 16.2% of the total river flows, Where as in USA it is 700 kmhf storage. The submerged area is increasing ( > 100 sq. km). The area commanded under tank irrigation was 4.5 Mha (in 1960 - 1961) and has got reduced to 3.1 Mha in 1985 - 1986: This is mainly due to siltation, and encroachment of tanks. Planned Development Between 1951 and 1985,246 major, 1059 medium irrigation projects were taken up, of which 65 major, and 626 medium projects were completed by 1985. During the 7th Five Year Plan, 17 major and 66 medium projects have been initiated, and in this period 58 I major and 303 medium projects were expected to be completed. In the 8th Five Year Plan period, 158 major and 226 medium projects were under various stages of development; r and 18 major and 57 medium projects have been initiated during this plan (Table 1.14 to 1.18). I I I Irrigation waters are available from various sources. Canals are the major water conductors from the large and medium rivers. Dams, barrages and anicuts are constructed I (Table 1.13) on the rivers to regulate the flow and excess water is stored in reservoirs to use at the times of deficiency. The storage in different basins varies according to their I respective tlows. Minor irrigation schemes include groundwater development by dug I wells, tube wells, and lift irrigation projects. Among the sources of irrigation in India as on 1985, canals (private an8 iovemment) rank as the foremost (Table 1:17). The ateas irrigated by different sources are as follows : canals 15.3 M ha, tanks 3.302 M ha, tube wells 13.635 M ha, wells 8.927 M ha, and other sources 2.965 M ha, leading to a total of 44.129 M ha. Table 1.13: Major Dams Constructed

Period Total Height > 15 m,

>15m 10 ti 15 m >r3':3 upto 1900 40 . 28 12 29 1901 to 1950 210 116 94 119 1951 to 1960 226 15 1 75 153 1961 to 1970 454 27 9 175 28 1 1971 to 1980 1002 553 449 554 1980 to 1989 740 412 328 412 Total 2672 1539 1133 1548 Date not knhn 266 113 153 113 Under Construction 696 487 209 493

Total 3634 2139 1495 2154 ' Uttar Pradesh has the largest area irrigated by canals, followed by Andhra Pradesh, hhjab and Haryana. Tube well irrigation too is generally high in Uttar Pradesh, Punjab and Haryana. Tank irrigation is highest in Andhra Pradesh, followed by Tamil Nadu, Karnataka and Maharashtra. Wells are common in Rajasthan, Gujarat and Maharashtra. The command area development programme was introduce+ during the 5th Plan,period Soil - Plant - Water - - thrnu~h with the main objectives of better and o~timumutilization of water resources- .------a-- Relatiomhip in Irrigation irrigation project-s. During the 7th Five ?ear Plan more emphasis was laid on improving the system catering to areas already under irrigation. Table 1.14: Planwise Irrigation Potential Created and Utilised (1000 ha) as of 1993 Period Major & Minor Total Medium P* U P U P u Pre - Plan upto 1951 9705 9705 12901 12901 22606 22606 1951 - 195; 2486 1280 1956 - 1966 2143 2067 1830 1830 6469 5177 1961 - 1966 2231 2123 1966 - 1969 1530 1576 4289 4289 8050 7988 1969 - 1974 2608 1937 4380 4380 6988 6317 1974 - 1978 4014 2475 3900 3900 7914 6375

1978 - 1980 1895 ' 1482 2700 2700 4595 4182 1980 - 1985 1083 929 7520 5248 10921 7933 1985 - 1990 2225 1756 9086 7871 11311 9627 1990 - 1992** 821 , 848 3743 3418 4564 4266

1992 - 93** 603 543 1786 1723 2389 2266 \ 1993 - 94** 708 65 1 1977 1745 2685 2396

5088 4252 -- 10709 9360 15797 13612 Ultimate Irrigation Potential: 15615 0000 ha. Total Potential Created (upto '92) : 8 109 1000 ha Total Potential Utilised : 72853000 ha; percentage utilisd 89.84% *P = Potential. U = Utilised Table 1.15: Irrigation using Surface Water (1991 - 92) (A) Major & medium projects for some selected States (1000 ha)

DISIIeS LCeaceo I Andhra Pradesh 5000 347 1 3234 Karnataka 2500 1494 1390 Maharashtra 4100 2p20 1293 Tamil Nadu 1500 1296 1281 Uttar Pradesh 12500 7459 6154 (B) Minor Irrigation* : (1000 ha) I States 1 ~ltimate~oteatial1 Created I Utilised 1 rn Andhra Radesh 2300 1306.18 1120.75 I I 1 Karnataka ! 900 727.80 700.09 I I Mahprasl~tra 1200 I 901.00 702.00 Tamil Nadu 1200 877.01 876.73 I Uttar Pradesh 1200 1018.00 I 975.00 * Minor irrigation includes surface water and groundwater. Table 1.16: Facilities Developed for using Ground Water Items Period Period Remarks 1984 - 1985 1989 - 1990 Dug wells (No) 8726 160 9486950 - Shallow Tube wells (No) 3358960 4754010 - I PublicTube wells (No) 46166 1 63584 1 - Electric Pumpsets (No) 5708570 8226199 - Diesel Pumpsets (No) 3553650 32065069 O(1986-1987) I Wind pump System (No) - 2362+ ( +ason31.3.1989 I Iot~.oductionto Irrigatio~~Engineering

Carlals Government 15872 Private Total 16357

Wells: Tube 13635 Others 8927 Other Sources 2965 L- Total 45 186

1.3 ADVANTAGES AND DISADVANTAGES OF IRRIGATION

Large scale development of irrigation facilities in an area have an impact on the environment (Box. 1.17). 1 Box 1.17 I Over Irrigation is Synonymous with Self Destruction Injudicious management of soil and water, out of ignorance or short sightedness, can destroy the otherwise bountiful soil-water complex. History of civilization shows that excessivt .evelopment of irrigation can ultimately become self destructive. I nShort term goln +Inverse rcttlrment IS not the direct coua I.Long term loss Wotcr Rcrwrce ~ep~etion I Water Resource pollut,'on

Ungauged application of,water to land with little control over quality or quantity is the beginning of harmful processes. In irrigation "Just Enough" is the best policy, neither less nor more. Too little water may fail to produce the expected results. Too much water would lead to flooding and saturation of soil; it impedes aeration, leachs nutrients resulting in greater evaporation and salinization. Groundwater table comes up towards the ground. It results in the need for expensive treatment. 1 Simply dumping back water into river increases salinity in the downstream reaches. Science and art of irrigation help "in gradual but sure acquiring of knowledge, and gaining more precise control over quantity and quality. Soil - Flant - Water 1.3.1 Environmental Effects Relatiomhip in Irrigation Though Nature has worked for millions of years promoting life, yet it has begun to display signs of stress on environment, primarily because of the impact of human activity. In natural state, life-forms live in harmony with their environment. Availability of resources should govern their number and activity. Interaction of species is basic in the food chain. Human beings alone have the ability to acquire resources from beyond their immediate surroundings and to process those resources into different, more versatile forms. But, the natural and manufactured wastes generated and released into the biosphere of increased numbers of human beings have upset the natural ecolugical equilibrium. This overloading of the nature is, however, of recent origin that has upset the equilibrium. Water development projects such as dams, reservoirs and channelisation, dredging, and allied irrigation schemes often cause significant beneficial or adverse impact on various components of environment and the consequences of such an impact on socio-economic, socio-cultural, and hydrological aspects become quite noticeable.

Noting that we can neither ignore the development of water projects nor can we II,I1 OW degradation of environment, harmony with Nature, through philosophical iuld religious appreciatioil (understanding) of the ecological forces that hold nature intact. is iniperative. Box 1.18 I What is Environment ? I In simple words environment can be defined as one's surroundings at local, or regional or global level. Global environment consists of atmosphere, hydosphere (hydrosphere consists of water bodies, such as, lakes, sea, ocean, streams, rivers, and surface and subsurface water) and lithosphere in which life sustaining resources of earth are contained. All the . three spheres put together make our biosphere. In biosphere life fornu of earth, including human life, exist. From the beginning of time, biosphere has received and assimilated wastes generated by plant and animal life. For every natural act of pollution; for every undesirable alteration in the physical, chemical or biological characteristics of environment; and for every incident that erodes the quality of the inmediate or local environment, there are natural assimilative actions that restore the quality of environment. However, the assimilative capacity mil sustaining capacity of nature are not infinite.

Conservation movement started in USA as early as 1872 [National Park System Concept till 1970, and Environmental Movement] with a view to blend "Environmental Welfate" and "National Interest". Environmental problems in India arise from a number of causes (Appendix 1.1). One of the reasons is the growing human and animal populations that are making increasing demands on natural resources resulting in the exploitation of resources in an unsustainable manner. While India has achieved great gains in industry and agriculture, it seems to have failed on the environmental protection front. The environmental problemlimpact can arise at macro-level andlor at micro-level. Box 1.19 Ecology To consider all the organisms, plants and animals living in a given area (or environment) at one time in terms of their total environment and adjustments to both the environment, and to each other is to study the overall ecology of the area. Such a dynamic system is referred to as an ecosystem. Air, water,. nutrients, heat and light are variously utilised, transformed, stored and returned to their respective non-living states. Ecosystem represents the combined use of the resources by plants and animals, that are provided in one place at one time by the surroundings. Quotes Soil, like freedom, is not appreciated until it is endangered. "Accuse not nature ! She has done her part: Do thou but thine!" The earth provges enough to satisfy every man's need but not for anybody's greed. -M. K. Gandhi The development of water resources should be carried out in line with fhe general environmental hygiene, sanitation, clean water for drinking and the protection of water and soil in addition to air. Environment and development go hand in hand if a purposeful life is to be aimed at. Environmental protection involves scrutiny of each aspect of development, and taking up measures for mitigating the adverse effects that cannot be wished away in totality. In fact, there are two view points that are to be reconciled with each other : environmentalists' view point and engineers' hddevelopers' view points. Activity 1.2 Write a note on the following: a) Legislative Acts of India regarding : i) The Wild Life (Protection) Act, 1972 ii) The Forest (conservation) Act, 1980 iii) The Water (Prevention and Control of pollution) Act, 1986 iv) The Env@onment(Protection) Act, 1986 v) Nationalfiver Action Plan, (1992). b) Discuss: i) The Chipko and Appiko movements ii) Kerala Sastra Sahitya Parishad campaigned against the Silent Valley Project, why ? c) What is an environmentally sound sustainable development? d) Nannada Bachao Andolan (Save Narmada Movement) At the planning stage of a project, following important aspects are to be considered with special reference to environment: ' i) Categorisation of environmental impacts commonly associated with the project. ii) The techniques for predicting the magnitude and extent of impact due to a water resources project. iii) Alternative procedures to evaluate competitive proposals in terms of socio-economic and environmental impacts. iv) Character of the implementing agency. In a typical environmental i'mpact assessment the term "environment" is defined broadly to include social effects as well. Mostly, a check list is produced for each of the'contending water resources projects, in particular regarding the impact of impoundment and modifications effected in the water carrying channel. The ecological impacts are to deal with the area of impoundment, downstream of the impoundment and the area where the water is used. Environmental Impact Assessment (EIA) for a pre-and post-situation is very essential. Lack of adequate a data has been the main handicap in such assessment exercises. Environmental impact assessment or analysis, implies a systematic examination of the environmental consequences of projects, policies and programmes so as to facilitate decision making; thus, the process can be taken. as a decision supporting tool. Several methods are available for assessing the environmental impacts : adhoc method, overlay method, checklist method,matrix method and network method. Of these checklist method' and matrix method ue popular. Environmental Impact Assessment lays emphasis on the following wpects: i) identification and quantification of all effects, both favoutable and adverse, ii) expected socio-economic benefits, and costs, iii) identification of activities which have a potential to affect the environment, and iv) identification of the areas of potential vulnerability. The net effect of the first two factors determines whether the overall influence of the project is positive or negative. The areas of concerned activities are; lahd use (agricdtlae, forestry), air quality, micro-climatic influence on meteorological parameters, water resources, ecology (endangereq species, migratory birds), socio-ecanomiC factor that is initiated by the project, reqreation, quality of water that is received. The major aspect of water use quality includesiidentification and quantification of water use for irrigation and domestic purposes. Table 1.49: Itrigated Area and Inputs : Statistics

Gross Area Arb Fertilizer Food Malaria under under Consumption Pro?uced LzdE Incidence Year Area H ation Hi$ (Million (MWon Agriculture (won)* (Mha) (dhaj Yiel ng Tonnes) Tobes) (1000 t) Variety (Mha) 1%0 152 28 Nil 0.2 8.0 I 2.0 Nil 1%6 163 32 1.7 1.1 74 7.4 0.10 1970 165 38 15.3 2.3 108, 10.2 0.60 1975 170 43 31.8 2.9 121 43.4 5.10 1980 175 49 43.0 5.5 40.6 2.80 I-1 2q 1985 175 59 56.0 8.0 153 1989 - - - - 170 *Spread of malaria is on theincrwe ( Down to Earrh, V 6, No. 9, Sept. 1997, pp.29 - 39) Hazardous chemicals used as pesticides, herbicides, insecticides should be identified and their effects are to be evaluated (Table 1.19). Pesticides are also toxic to eart11wo1-~n-a friend of the farmer. Ecological imflact can be considered at the site of impoundnlent, at the downstream, at the diversion arqs, on the areas of water use and i~ the coastal areas; however, it is to be understood that building reservoir projects brings hitherto unavailable water security to semi-arid regions and thereby increased prosperity to the thrget population. Physical, chemical and biological factors influencing water quaiity are interrelated in that a change in any water quality parameter triggers o+er changes in a complex network of interrelated variables. The physical influenw of hydraulic structures constructed for irrigation or multi-purposes are: i) resettlement of displaced population, ii) reservoir sedimentation, iii) waterlogging, iv) deforestation, v) impact on pisciculture, vi) water quality, and vii) impact on kcroclimate. Rehabilitation of persons displaced in the process of creating a project is a very sensitive issue. When a person living for ages in an area is to be shifted to a new environmeM he will have a cultural shocy, ahd a ps~chologicalproblem of adjustment. To lose a land yielding high dividends ahd get compensated by only an equivalent land area is not enough : it is, appropri3te that an environrnentaly equivalent land is made available. The soil fertility, and soil moisture too are to be compensated for. In addition, the gestauon period involv~dfor productionlyield should also be taken into accowt. The economic potential of an aged'person goes down; and for a person to develop a new land, having spent his youthful years, would be a torture, and any form of physical and monetary wmpensatio~would be inadequate. In recent times there is a strong movement launched by several environmentalist groups opposing the construction of big dams, such as, under Narmada Project (Sardar Sarovw, Indira Sagar). One of the major objections projected is the submergence of large agricultural (50 681 ha) and forest land (56 066 ha); and proper rehabilitation of displaced people is yet another point demanding satisfactory solution. Execution of this project results in cutting of 80 million trees. Climate and the rain cycle will be affected due to denudation of the forest. In addition, local oxygen balance and micro-climatic conditions will be affected. Aisb, it is believed that big reservoirs may trigger seismic activities and as well as submerge priceless assets such as shrines, temples and parks, and minerals. The landless category of people are very much affected and it is difficult for them to get the jobs in new environment. Irrespective of the ethnicity each group passively or actively opposes/resists the displacement due to eviction. The submerged areas, in general, include villages, roads, agricultural land, scenic spots, forest land, and private land (Table 1.20). Table 1.20: Reservoir Submergence . I 1 I ( ~ardar~arovar 1 67000 people will be effected I 1 Narmada Sagar ( 90000 people will be effected I Bana Sagar 228 villages, 35534 ha private land, 14777 ha Government land and 4428 ha of forest land. 100000 people will be effected

5200 ha submergence, 96 villages will be effected

Activity 1.3 Write a note on: i) Narmada Water Distribution Tribunal. ii) Sardar Sarovar Rehabilitation Policy. Quotation :Do not throw away the baby along withbhe bath tub Accumulation of water in a reservoir denudes that strip of land of forests, wood, bushes, shrubs and or grass - a process that disturbs the basic ecology and changes the landscape disadvantageously. Fluctuations in the level of the impounded water are produced by the operating conditions of reservoir systems. This could denude Ihe strip of land along the reservok rim. The rim area would be filled with shallower, but muddy water and can often become the breeding place for mosquitoes - a source of infection. The catchment area gets affected due to migration of inhabitants and their resettlement somewhere else. Along with them the grazing area gets shifted and new areas get cultivated. These human activities affect the land gradation and creates new possibilities for soil erosion. Annual migration cycle of wild file is also affected by resettlers' interference. The inevitable acquisition of land for setting up of major water resources development projects may result in the loss of livelihood and uprooting of a large number of people from their traditional homes. People displaced by large projects are forced to relinquish rights to various immovable assets viz, housing, and land, as well as access to econoinic activity, etc, and it is not an easy proposition. Reservoir Siltation Due to the construction activities associated with a project, vegetation is removed and more dust and sediment is generated. The silt content of flowing water is further altered due to change in turbulence characteristics. The amount of sediment carried by a river is a function of the type, size and nature of its watershed and the land use pattern. So far in Indian context no very serious negative impact, namely, serious siltation of reservoirs is reported. Reservoir project costs in some cases also include the cost of catchment treatment; thus it helps improve watershed management, and hence, it enhances the life of the reservoirs Soil - plant - Water due to reduction in soil erosion itself. Relatiomhip in Idgation ' Some of the recommendations of Government of India Committee formed ul 1978 regarding sedimentation of reservoirs are as follows: . . i) Flexible operations of reservoir consistent with the requirements would enable maximum consolidation of deposited sediments : thus prolonging the life of a reservoir; ii) In any iritegrated plan, construction of upstream reservoirs should not be delayed; and iii) More attention to the periodic surveys of existing reservoirs, soil conservation and comprehensive watershed management should be bestowed. Recent survey, in 1984, shows that 58% of the agricultural land (80 million ha), 33% of the forest land (20 million ha), 86% of the culturable waste land etc., are subject to severe erosion. The degradation of forest and pasture lands in river catchments contribute to the disastrous floods and sediment yield. Survey of 21 reservoirs has indicated that they receive sediment at the rate of 8.51 ha m per year per 100 sq km of catchment area against the designed rate of 3.02 ha m per year per 100 sq km of catchment area, which is . equivalent to about 182% more sediment yield than the designed value. Tables 1.21 to 1.23 depict the effects of siltation and Table 1.24 shows the variation of suspended load during monsoon and non-monsoon seaso* in the case of Cauvery at selected locations during the period 1982 - 1989. Table 1.21: The Modification of Reservoir Capacities due to Change in Sediment Rate

Table 1.22: Annual Rate of Silting

Annual Rate of Silting S. No. Reservoir Year of Reservoir Fing Design Rate Observed Rate* , ha mt'100 sq krn ha m/100 km and year of?urvey 1) Bhakra 1958 4.29 5.93 (1973) -----2) Panchet (DVC) 1956 6.67 10.00 (1974) 3) Maithon (D\~C) 1955 9.05 12.38 (i979) 4) Mayurakshi 1955 3.75 16.48 (1969) 5) Tungabhadra 1953 4.29 6.03 (1981) -----6) Mataila 1956 1.33 3.82 (1974)

(Source:Ministry of Water Resources, 1986). Note : * No correction for silt density has been applied. No consideration is given for possible .consolidation of the deposition in the reservoir with the passage of time. Observed rateis over the period from the year of impounding to the year of last survey for which results are presented. ' Table 1.23: Loss of Storage Volume Intmdiction to Irrigation Endnee* Reservoir and Year of Storage Average Rate of Silting, . Total Loss of Impounding Ca ace Storage (9%) (Am ) ha dl00 sq Year of km Survey Nizw sugar 1930, (AP) 841.18 4.891 1975 56.76 Himayah sugar I927 (APJ 107.79 4.467 1976 25.56 Mettur 1934 (TN) 2708.76 2.520 1983 19.69 Dhkwan I 907 (UP) 106.45 . 0.304 1980 44.55 Ramappa sugar Lake 191 9 82.48 2.583 1975 Lakkamavaram 1909 (AP) 60.42 10.650 1975 Shanigram Tank 1891 (AP) 29.08 1.134 1972 Palair 1928 (AP) 56.66 0.146 1977 .Wyra I929 (AP) 24.66 2.870 1977 . .40.00 Manjira 1966 50.94 1977 36.77 Krishnagiri 1957 68.25 1974 26.05 Srirama sa,qar 1970 2171.94 1984 25.05 Kedm I958 124.43 1977 37.10 '.. Matatila 1956 1132.70 1984 30.76 It may tw stressed that Sedimentahon rate, depends on the age and size of the reservoir. Reference :IS: 12102.(1987) : The guidelines for Determination of Effects of Sedimentation on Planning and Performance of Reservoirs. Table 1.24: Seasonal Suspended sediment Load (in 1000 tonnes) Observed ' in River Cauvery at Selected Sltes for the Period 1982 - 89

C = Cauvery, K= Kabini, A = Amaravathy, B = Bhavani Source: C.W.C., Ministry of Water Resources Pisciculture The water resource projects modify the velocity of the flowing water, temperature, other factors, and stream bed configuration which influence the quality of water (Figure 1.9). This affects the life cycle of fish in the new environment. This aspect was clearly established through the studies conducted in Damodar Valley Corporation reservoirs, and Pandoh reservoir of Beas river. ''Indian Shad" production (catch) was reduced as much as from 60% to 5% over years. SOB Plant - Water Box 1.20 Rdotiomkip in ImIgPSiw Fresh water fish gets reduced in number due to the ageing of water in a reservoir, and due to large scale extraction of gravel stones from river bed and dumping of chemicals from upstream. The world famous gare fishes; the Mahseer (Tor Spp) and the Indian trout are victims of dams and weirs constructed in the higher reaches of tributaries of major rivers of India. Y

Reference :Pmreedings of First National Symposium on Envimnmental Hydraulics, .lude 24 - 26, 1992, held at CWPRS Pune.

Solar racaation Phytoplankton Chbrophyl(

f Water temptuture I f ~utricnl I

Jan. Jum Jan. Jan. ~une Jan. Time ot year , Time of year

FSgnre 1.9: Bmic hoeess of Phytoplaokton - nutrient lnterrlction (Tlromann and MwUcr, 1987) Whereas under certain situations there are instances where matly Species hatre taken firm hold and contributed to large fish production, such as, Gangetic CSp has in~re~sedin Krishna and ~au\rer~'reservoirs.The presence of a reservoir, it has been obserqed, has led to increased fish growth and hence to additional income. Fish productivity in reservoir varies from 1 kgkdyear to 115 kg/ha/year. Provision of fish ladder, ps is providtd through dams, barrages, and weirs, helps in easy migration of fish along the coursq of a river. Table 1.25: Heavy Metal Contents (mgg) Found in World's Major Rivers

Heavy metal contents Fe 48.00 Pb 0.150 (mg/g> Mn 1.05 Cd 0.001 CU 0.10 Ni Not detected ' Zn 0.35 Co Not detected A portion of heavy metals (Table 1.25) that is dissolved by the reagents may become bio-available under certain physico-chemical condition, or due to mi~robialactivity, and he,we is very important from the point of view of aquatic life. If fish are affected and later the birds consume them, the birds may die leading to their extinction. Interaction of chemicals can produce more dangerous compounds than original chemicals themselves. Selenium tomicosis of fish occurs due to phosphate poisoning. Due to the presence of pesticides, snails, oysters, crabs, shrimps, frogs and other aquatic creatures tend to disappear in the zones bounding the reservoir. Every lake goes through a life cycle and this period may vary from a few days to few decades. Lakes are likely to become shallower because of the progressive deposition of inorganic and organic matter brought in by the runoff that also gets consolidated with time. The contribution from the adjoining areas ~wuldbe in colloidal, suspended or dissolved form. Algae and other plant proliferate under these conditions and often appear as a green scum. Various stages in the life cycle or operational cycle of the lake: from having fresh, clear, sparkling water to shallow, growth chocked, scum surfaced, or turbid muddy water are a common experience. These changqs occur because of multi-directional interaction of physical and biological factors that are involved. Schistosomiasis (Bilharzia) is one of the diseases'whose transmission is helped by the.. . creation of water bodies; there has been an increase in the incidence of such cases in introduction to Africa amongst the people living around the shores of reservoirs and lakes. Snails (which lmgntieh Engineering require a stagnant pool of water to live) act af parasitic hosts for the above mentioned I disease. Onchocerciasis (river blindness) is also due to man made lakes in tropical regions. Excessive fishing in the lakes may lead to the generation of leaches like Erpodella and Herpodella (as happened in the case of Ramgarh water reservoir in 1972) due'to the increase in molluscan. This increase in molluscan is due to overfishing of certain kinds of I fish which thrive on it. The fish management to be practised depends on the critical ratio of water, nubient density, and biotic index. Genu Vulgunl (knock linee) was caused due to the presence of soda alkaline fluoride-rich water and molybdenum-rich food grains along the shores of Nagarjuna Sagar affecting thousands of children. Water level management during a season is an important aspect in this respect and is to be considered with regard to operational aspects of reservoirs as linked with irrigation requirements. Phosphorous load monitoring in lakes is also very important. Transmission of water-home diseases (gastro-enteritis, amoebic dysentery, cholera, typhoid fever) is common, and the modes of transmission of pathogens are through ingestion of contaminated water, food and expqure to infected persons. Infections of skin, eyes, ears, nose and throat may result from immersion of a person in water for purposes of bathing. The impact by pathogenic bacteria, viruses and parasites is caused during shell fishing also, such as harvesting for calms and oysters, and moreover, through secondary contact while boating and fishing. Table 1.26: Examples of Communicable Disease Indicators and Organisms

Indicator Viruses Bacteria Total Coliform Hepatitis A Fecal Coliforn~ Enteroviruses Fecal Streptococci Polioviruses Obligate anaerobes Echoviruses Bacteriophages Coxsackieviruses Pathogenic Bacteria Pathogenic Protozoa and Helminths (Intestinal Worms) Vibro Choleras Giardia Lambia Sa1mc)nella species Enameoba histolytica Shigella species Facultatively parasitic amoeba Nematodes

Some of the physical effects of storing water in reservoirs are : light attenuation, hydrothennal behaviour, convective heat transfer, wind sheltering, han e in water colour, suspended material, n~orphometry,modification in evaporation, etc.

Total coliform could be found from both polluted 'and unpolluted soil samples in addition to other sources of feces. Degrec of horizontal and vertical stratific:ation in lakes have significant effect on other aspects of water quality. Dissolved Oxygen (DO) depends on thermal stratification. The thicknesses of layers change depending on the temperature variation -if surface temperature falls then the hypolimnion layer comes up and vice versa. Due to low conductivity. of heat and absorption of heat in the top few meters, vertical temperature gradients are caused. Eutrophicution is the excessive growth of aquatic plants, hot11 the planktonic aquatic plants (move freely with nature) and those that remain attached or fixed, are considered as an interference with desirable water uses - it occurs in reservoirs; and proper,. effective management is required to control it. One of the principal stimulants in this regard, is an excess level of nutrients such as nitrogen and phosphorus (Tables 1.27 and 1.28). In recent years this problem has become acute due to the discharge of such nutrients from sources such as agricultural waste water, urban runoff, ~nunicipalrunoff, industrial runoff. The important variables in the analysis of eutrophication are : Soil - PI& - Water a) solar raa~auoe; Relatiomhip in Imgstioo b) geometric characteristics of the water body: surface area, depth profile. volume; c) velocity of flow, flow rate, dispersion; d) water temperature; e) nutrients (N, P, Si); f) phytoplankton (Chl-a). Table 1.27: Trophic States of Lakes (Reference :Thomann aud Mucller)

* "Chlomphyll-a"concentration (gfl) is a measwe of the gross level of phytoplankton. The basic process of phytoplankton - nutrient interaction is shown in Figure 1.O. Nitrogen occurs in four major forms: ammonia, nitrite, nitrate and organic form. The first .three are the inorganic part of nitrogen which are used for growth of phytoplankton. N1 P ratio also plays an important role. Water quality modelling of reservoirs under changing conditions (air temperature: humidity, precipitation, wind, watershed runoff quantity and quality) poses' a challenge. Impact of projected climatic changes 011 reservoirs is a growing concern. The triodels which forecast temperature, dissolved oxygen, as well as their impact on the sulvival and. good growth jmtential of fish are of primary concern. Reservoirs are classified according to surface area, maximum depth and trophic level expressed as Secchi depth (Figure 1.10 and Table 1.29). Seechi depth (depth at which the target just disappears) represents the coefficient of extinction of the seechi disk. . Table 1.28: Parameters under Trophic States '-.

\ Akrage Plytoplankton BOD Chlorophyll , Trophic Status (CLg 1 -I1 C~I-a (p g L

1. 6 I Mesotmphic / 0.75 I Oligotrophic 0.50

~lo~sificot~on

Maximum Ocpth (m) Table 1.29: Production-based Classification of Reservoirs Int~wductionto Irrigation Engineering Clear, low productivity lakes Oligotrophic Intermediate productivity'lake Mesotrophic High productivity lake relative to basic natural level Eutrophic The impact of environment on food production, and production of egg, on sugar industry and milk production%& been positive due to inprovement in agricultural practice. Ijowever, intense cultivation of land without conservation of soil fertility and soil structure would ultimately lead to desertification. Irrigation without proper drainage would result in soils getting alkaline (pH>7) or saline. lndiscriminate use of pesticides, fungicides and herbicides could upset the biological balance, and the presence of toxic residues in the food grains or other edible parts may lead to the incidence of cancer. The improper cultivation induces increase in sediment erosion; it may, here, be pointed out that contour cultivation reduces runoff and prevents soil erosion compared to cultivation done across the contours - more and more agricultural development requires better top soil. Soil fertility as well as soil moisture are also conserved by adopting contour cultivation, and obviously heus to increase the life of reservoirs. Deforestation brings lot of sediment into reservoirs. The impact of reservoir on forest submergence is negligible when compared to the deforestation that is taking place due to cutting of timber for industrial requirements. Infact forests must be developed if agriculture is to a survive on the existing extensive scale. Therefore, scientific forest management implies proper planning. Lastly, it may be said that even the quality of groundwater cannot escape the impact of on-ground factors. Increase in nitrate concentration in groundwater is attributed to the use of fertilizers and poor agricultural practices. Nitrate solute has been traced upto 8 m depth of soil. Similarly, traces of pesticides are foundin groundwater. Waterlogging Agricultural land is said to be waterlogged when the soil pores in the crop root zone become saturated with water. This is usually caused by high subsoil moisture and accompanied by periodic flooding, overflow of runoff, seepage from canals, over irrigation, impeded surface drainage conditions. As a consequence osmotic pressure in the root system does not function properly, thereby affecting the growth and yield of the crop. Waterlogging is generally experienced during the initial phase of development of irrigation. During the initial phase of irrigation, the drainage system is usually not ready. , The adverse effects of waterlogging could be taken care of by adopting following measures : i) conjunctive use of water, ii) lining of canals and field channels, iii) levelling ofirrigated lands, and iv) adopting water resistant crop varieties. In India, the percentage of waterlogged land in command areas of grojects ranges between 1.5'to 10% : Nagarjuna Sagar 7%, Mula Project 7%. Prolonged waterlogging in many projects like in Westen) Yamuna Canal area that has resulted in an increase in the incidence of malaria. Box 1.22 Lack of drtinage, control structure, and unlined canal system aggravate qeproblem of waterlogging. If tanks (i.e., depressions etc.) had formed a part of the command area, and their beds are encroached upon for cultivation by irrigation, the practice leads to the destruction and disintegration of once existing drainage, such as what happened in the semi-arid area of Chambal canal system. Health hazard, in general, is another important issue. A badly managed irrigation project system often spreads pesticides and insecticides, nitrates, toxic salts (degraded saline or sodic water) in the command area, thus polluting the ground water too. Too much of water may creap certain species of birds to disappear and certain other types of birds Sa4t - Plant - Wnter may migrate. Further, the polluted retum flow to river may endanger certain species of Relmthskip in brigation fish as well. Box 1.23 Continuoros waterlogging favours 1) Preservation rather than decomposition Gf organic matter. 2) Deterioration of soil structure : This may take place by allowing nitrogen, present as nitrate nitrogen, to detrify and get lost to the atmosphere as nitrogen and lead to the formation of nitrites, hydrogen sulfide, ferrous iron which are toxic to the roots of plants. This affects the soil fertility aid in rum affects the yield. Accumulation of rain water, and retum flows from farms, combined with choked drains due to weed growth are additional factors that cause rise in water table level. The presence of clay with low permeability in the near surface layers precludes effective drainage of water. Such high water level, say in monsoon season, may prevent planting of crops such as wheat, mustard (as in Chambal system). Land levelling may cause reduction of fertility due to top soil dislocation/disruption in the initial two year period and putting extra financial burden on the farmers, particularly sinall land holders. Over irrigation is yet another cause for lower irrigation efficiei~cyand it is conducive to waterlogging in case of flat terrain. However, while on one hand our country is progressing towards the achievement of self sufficiency in food, but on the other hand the development of new land areas may result in denuding our valuable forests. During 1951 - 1976 alone 476.1 x lo3 ha of forest area have been shbmerged due to river valley projects. This way our forest cover is fo~undto disappear at the rate of 1.3 M ha per year, mainly due to change in landuse. This causes soil erosion in watersheds. In fact forests must be developed if agriculture is to survive on any extensive scale to take care of our food requirements. The annual soil erosioi~is estimated to be 6000 million tonnes including the removal of 6 million tonnes of nutrients which is more than the 50% consumption of chemical fertilizers. Nearly a tenth of the soil eroded gets deposited in the reservoir, and river courses; thus, the estimated life of reservoirs gets reduced. This, in effect, causes reduction in storage and tlood absorption capecity. 13.2 Environmental Issues - Environmental Impact Assessment (EIA) Escalation of environmental degradation and the resultant hazards from over exploitation I of natural resources to satisfy the ever increasing demands of increasing population, particularly on the food front, has created lot of concern. Recently several organisations have betn tk~~y~.;ingthe construction of large reservoirs such as Tehri, Bodhgat. Narmada Sagar. In fact, 26 international environme~ltalprotection groups have questioned the wisdom of tlie World Bank for financial support to Narmada River Development scheme. When we talk about impact it has two facets: positive as well as negative; and human tendency is to exaggerate the negative aspects. Submergence of forest area may cause the loss of flora and fauna of several centuries and the suggested compensatory activity of afforestation may not be feasible due to non-availability of suitable land. Historically, many cities, towns, and civilisatioils are known to have been victims of negative impact. If there is no intervention and skilful1 operation and maintenance of reservoirs. they will be loaded with sediment and groundwater tables will rise, salinity would spread destroying the very base of agriculture. Environmental Impact Assessment (EIA) and Environmental Impact Statement (EIS) are required to be prepared; UN Conference held at Stockholm in 1972, advocated that. requirement. EIA is an exercise to evaluate the potential dangers inherent in a project which may cause damage to environment. During the 7th Five Year Plan, the Ministries of Irrigation both in the Central Government and the State Governments were advised to establish Technical Cells for EIA. The selected indicators for EIA are listed as under : Extent of forest cover denudation, Introduction to i) Irripntiw Endneering ii) Rate of desertification, iii) Waterlogging, iv) Salinity and alkalinity of soil, v) Modification of water tables, vi) Rate of change in the population of endangered species, vii) Residues of pesticides in water bodies, viiij Submergence of cultivated and uncultivated water land, and . ix) Submergence of forest. . An impact qatrix (Box 1.24) may include environmental, socio-economic, river morphology, water quality, and coastal hydraulic aspects.

Box 1.24: Impact Matrix Physical Impact a) Sedimentation b) Increase in seismicity c) Submergence of land d) Degredahon of forest e) Change in hydrological regime of river - i) river morphological changes due to committed downstream release ii) permanently taking away (diverting) water causes higher sedinient deposition in the downstream portion of the river, sea water intrusion etc. iii) increases recharge over some areas f) Impact on other resources g) Increase in irrigated area, hydro-power generation h) Submergence of historical monuments and archeological structures ' i) Salinity intrusion in deltatic areas j) Waterlogging k) Salinity in irrigated lmd 1) Quantity of water diverted from river and its effects m) Drinking water availability Biological Inlpact a) Public health b) Wild animals and bids c) Important local species d) Availability of biomass Impact on Human Life a) Sociocultural aspects b) Resettlement requirements c) Tourism d) Land acquisition e) Number of farmers benefited Soil - Plant - Water A case study of Indira Gandhi Canal (Naharj project has brought out the eilvironmental Relatiomhip in Irrigation effects of water resources developmeilt in the conceped region (Appendix 1.1). The widespread use of chemicals in agriculture and industry has introduced inany new compounds into the environment. Some compounds get diffused throughout the environment but some get concentrated near the disposal sites. Such chemicals spread through air, water and soil as well as through the food chain. Use of pesticide such as DDT has adversely affected many "non-target" species, and almost in all living organisms throughout the world this effect could be found. Clean air and water are an aesthetic delight and a birth right of human beings. The fertilizer nitr~genhas started appearing in the ground water in some areas of -jab. Ratio of fertilizer to pesticide remained nearly constant at 100 : 1. Moreover, water in an irrigation system is drawn from its source and diverteo for erse in food production. 'This has a direct impact on the downstream releases. Certain nlinimum water is usually required to flush out the pollutants in the downstream and particularly in coastal areas. Planning is to be carried out so that "the annual draftof water that can be withdrawn is limited to avoid undesirable effects" Depletion of both surface water and occurs due to its use in agriculture. Because of the high withdrawal and consumption, the need for conservation in * agriculture is very high - conservation and reuse of irrigation water mean development of more productive and/or salt tolerant crops, and also increased use of chemical fertilizers, pesticides, herbicides; lining of irrigation canals or the use of pipelines to prevent seepage loss; trickle or drip irrigation; and reuse of irrigation water. However, introduction of high yielding varieties changed the agricultural environment leading to numerous pest problems affecting the economics of agriculture. Many of these pests were unlplown during the sixties. Increased irrigation, higher use of fertilizers and high yielding varieties led to the resurgence of pests. The increased irrigational facilities in traditional rainfed areas led to the upsurge of jassids in Saharsha district of Bihar, cut-worms throughout the northern belt of Gandak command areas and army worms on * winter maize of Gujarat, Maharashtra and Delhi. High yielding varieties and monocultu~practices led to a material change in pest infestation. Pests and diseases such as of all midge, brown plant hopper, bacterial blight, turgro virus of paddy which were of minor importance have become major concerns after the Green Revolution in our country.

Offstreamuse : withdrawal of water and consumptive use. Instream use : water used without removing it from the source,.for such purposes as navigation, recreation. Plus and Minus of Development Water resources develclh?~;ira!tin general is the surest path aimed at poverty Jleviation md ilnprtjvement of quality of life. It affwds flood protection in Ule downstrea~n,increases production of oxygen due to increase in the growth of vegetation; provides transition opportunities to i~dc~ptto new life style during the gestation period; and helps in the "fixation of CO2". Protection ' against advancing of That desert to Rann of Kachch is attributed to water resources development. Improved habitat for water birds, non-migratory fish. In Bhakra reservoir fish production went up by 6 times 'the average, 14.6 kgha (in 1991).

great concern; mosquitoes have

No doubt imgation provides water for parched land but it is to be recognised that the situation becomes distressing when the same land runs the risk of losing its productivity as a result of this very facility, mostly because enough attention was not paid to the drainage requirements of the land. Therefore, the latest suggestion is to encourage minor irrigation only; and the idea of restoring tank irrigation is gaining acceptance in this Introduction to context. Irrigation ~nineerin~ The supply of irrigation water provides higher rechqge opportunities; sometimes it is nearly three 'times more than that "under natural rainfall". The increase in salinity and waterlogging, as pointed out earlier, depends on the intensity of irrigation, type of soil and its drainability which is the charachteristic of the geological formulation, topographic conditions and the status of surface drainage. In upper Ganga, the canal system (commissioned nearly 135 years ago) has been operating as an unlined system down to the minors and water courses, and has been delivering nearly 294 m3 si' water to the command.-Intensive irrigation (as high as 180%) is practiced, even then no problem of waterlogging and salinisation is reported. The ground water table has, no doubt, gone up but due to conjunctive use in the command area under private minor irrigation works, the rechargi? has sustained this system well, otherwise with the formation of high water tables, when water evaporates from soil, dissolved salts left behind in the soil concentrate new the surface (salinisation of land). Similarly, in lower Ganga canal system (100 years old) and Sarada canal system (60 years old) these problems are not faced except in some pockets. And, in Haryana and Punjab canal network has been working on a sustained groundwater use (1.2 million tube wells) without any trouble. Otherwise, salinisation affects the growth of crops in two ways: i) reduction in absoqition of water by the roots due to increased osmatic pressure of the solution. ii) adverse modification of the physical properties of the soil, forming materials which are toxic to roots.

Box 1.26 ~estl~isease,and the Crop Affected i)' Spodoptralitura: Cotton Maize Tobacco ii) F'yrill. Wheat Maize Sorghum iii) Apple Scab: Codlingmath Apple iv) KarnalBunt: Wheat

Box 1.28 Efficient use of land and water resources through irrigation is, to a great extent, dependent upon solving the problem of salinization control. Out of the total area under active farming over 50 x lo6 ha is salinised world wide.' Average damage due to under harvesting in these areas amounts, as per even a modest estimate, to Rs 9600 crores. Sdl - Plant - Water Weed Infestation ReUhmhip in Irrigation The belt adjoining the water conveyance system could be the breeding ground for weeds. Even conveyance system itself may be chocked with aquatic weeds resulting in insufficient flow due to reduction in flow area as well as increased resistance. Over intensive cultivation due to "two" or "three" crops may not provide sufficient time for the nature to restore its biotic balance, and also destruction of pests and pathogens may lead to disastrous consequences. The increase in yield per unit area has given rise, at several places, to soil health problems such as deficiency in micro-nutrients and organic matter. There are instances of damage to the physical structure of the soil in the intensively cultivated areas in addition to soil salinity that has taken place. Soil Health Care of Water Quality Denudation of vegetation and over grazing have made large areas vulnerable to drought and floods. The consequent loss of infiltration resblts in flash floods scouring away good top soil. Such avoidable damage is accompanied by more disastrous sheet erosion of precious soil which has been formed on geological time scale. Neglect of land, therefore, irrevocably erodes the foundation of agriculture over large areas. Mesopotamian irrigation system was wiped out because of such deterioration occurring with no corrective measures having been taken. Command area development (CAD) projects have bben taken up to retrieve large chunks of cultivable land which had gone waste due to waterlogging, salinity of soil 'and infestation by weeds. This (CAD) includes proper levelling, management of erodible land and providing appropriate drainage of land. Initiatives in this respect were taken urn 5th Five Year Plan through six pilot projects in Rajasthan (Chambal river command), Madhaya Pradesh, Andhra Pradesh and Bihar. It is estimated that only 60% of the chemical fertilizers that are applied is actually utilised; the rest of it gets into surface and subsurface water as contaminants and may find their way into drinking water. Health risks arising from the use of waste water obtained from irrigation systems also pose a problem that needs attention. The Ganga Action Plan (GAP) is one of the national projects intended to improve the quality of the river water. A large number of industries along the river have contributed to the general deterioratiqn of the quality of its water. Now the Central Government has initiated National River Conservation Plan to conserve the quality of river waters. Impact on Climate Impact of water resources projects on climate should be viewed separately for different climatic zones of India. Increase in humidity and reduction in maximum temperature in arid and semi-arid regions may be welcome. Heat storage action of a reservoir, uld lag in the time required for heat transfer tend to reduce summer temperatures uld increase winter temperatures. 1.3.3 Sustainable Development .Unfortunately the concept of sustainable development is quite vague. The existing literature does not clarify the term in an unambiguous manner. However, in general terms, sustainable development can be said to be an interface between environment and development. Sustainability has to be based on scientific technological concepts, as well as on the influence of market mechanism. The economic use of the existing resources (Appendix 1.2) alone will not entirely help in sustainable development. As the demand increases, cost will increase and sustainable development will also become costlier. The market mechanism has multiple inputs into the scheme of sustainable development. Further, a set of given parameters nlay make it imperative to choose between feasible technology and viable techlaology. lllese are the problems that the concept of sustainable development has posed to us. Elite consumptio;? has become a problem and cannot be sustained even at the present level. Sustainability is not just an issue of technology or market but it as an ethical issue also. Sustainable development has also to consider the following aspects : a) Equity, both at national and international level. b) Institutions regarding the decision making mechanism, and levels of decision making. Cooperative endeavours - what induces the people to participate'! lntmducnon tn c) Irrigation Engineering d) Political value system. Earth Summit at Rio in 1992 was a serious stock taking effort at global agriculture and food security. The idea was to review the sustainability of approaches adopted to improve crop, animal and aquatic productivity. The conference concluded that the present approach should be changed in the context of the fact that the irrigated agriculture utilises 80% of the water, out of which 60% is wasted. This implies a necessity for laying stress on conservation of water and improving irrigation efficiency by proper management. Agriculture production in India has come down to 167 million tonnes against an estimated target of 182.5 Mt in 1991 - 1992. Though the per capita food production had increased to 119 in 1989 - 1990 on a base level of 100 in 1979 - 1981, the real challenge now is to further increase the per capita production level and to plan for better distribution. Sustainable development must, in fact, be preceded by the strategy for sustainable life, in which every individual is accounted for. A system which tries to survive by ignoring inequalities in a huge society like existing in India will neither be tenable nor sustainable. / 1.4 SUMMARY This unit discusses, in brief, the need for irrigation; and, also the essential elements of planning in this regard. Later on, the thrust of the presentation is directed towards giving a bird's eye view of the history of development of irrigation in India, particularly since ancient times. Further, advantages and disadvantages of irrigation, and the ecological changes brought about by the construction of water resources projects are dealt with in detail. In this .regard assessment of impact on environment assumes its own importance, and this aspect has also been dwelt on. Lastly, an important facet of all our efforts to usher in progress, namely, the concept of sustainable development has been presented in order to emphasise the importance of a balanced perspective about total economic progress of the country.

Sustainable Development : A long-range development aiming at the betterment of I both the present and future genertions I Land Holding : Land held by a tenant (or owner) 1 = Communicable Disease : A diseases that can be transmitted through several (or I one) nodes I 1.6 ANSWERS TO SAQs

For answers refer to the relevant portions of the text, as well as the relevant reference , material mentioned under section "Further Reading" at the end of the block. Soil - Hant - Water qppendix 1.1 :Some Aspects of Environmental Changes in Command Area Re1aliomhIp Injgation ReservoirlArea : Affects existing settlements in the submergence area. Accumulated water, as well as the fluctuating water levels could denude a strip of forest land, bushes, grassland, etc., and disturb the local ecological balance.

Water quality changes, particularly elevated.levels of nuturients in water due to excessive use of the former, may cause plantation bloom. Stratification of tempeiature and dissolved oxygen, and growth of aquatic weed, however, support better growth of forest aid providb assured water for wild animals.

Accumulation of mud and shallow water regions near the rim of the reservoir causes mosquito menace. Dm to shallow pool fishery, recreation, etc get affected near the rim. However, the formation of reservoir over wide-spread area may bring tourists, create facilities for water sports such as skiing, boating. Irrigated Area : Conversion of non-agricultural area to agricultwable area may change the landscape through the growth of new plantation on irrigated soil, transformation of forest and woodland into agricultural land.

Chemical Fertilizers bring in change in the quality both in surface and groundwater. The contaminmt may render water unpotable. Catchmen Area : Migration of people, and their resettlement in the 't catchment area, and also the use of animals, for tilling agricultural land, and other activities affect land gradation. Consequently, increased soil erosion, and pollution affect the life to reservoir, and quality of water in storage. Migration of wild animals due to the disturbance caused by resettlers adds to the ecological imbalance already triggered off by the water resources project per se. Categorisation of Total Impact on Environment by the Construction of a Dam (Reservoir) 1) Direct loss of land andlor productivit$ a) Specified land uses i) Agricultural or grazing land ii) Forests and timberland iii) Weff ands or marshlands b) Commercial productivity i) Mineral Resources (gravel, limestone, oil & Natural gaq) ii) Commercial fisheries 2) Losslrelocation of structures, archaeological and historical sites, and built up areas a) Archaeologicalihistorical monuments, etc b) Cemeteries * c) Homes or villages d) Highways, railroads and other means of transportation e) Recreation facilities 3) Loss of wid life habitat a) Desired specification of the habitat b) Loss of hunting opportunities a. -. *. .. I a) Decreased aesthetics Introduction b I Irrigation Eogiworiag I b) Increased aesthetics 5) Loss or inundation of natural streamlstreams a) Loss of the stream fishery b) Loss of recreation potential I 6) Environmental impacts due to the reservour per se l a) Substitution of a lake environment for a stream environment b) Creation of a warm water fishery c) Creation of wild life habitat 7) Alterations in water quality due to impoundment a) Thermal stratification b) Growth of algae I c) Impoundment of nutrients and wastes - i) Decrease in water quality ii) Increase in rate of eutrophication 8) Impact resulting from a dam acting as a barrier to the river it obstructs a) Increased sediment depostion b) Loss of anadrowus fish runs 9) Impact due to spillways 10) Downstream effects a) Decreased silt or sediment in downstream channel -

I i) Increased erosion downstream ii) Improved water quality in the downstream reaches b) Improvement or enhancement of fisheries, water quality, recreation, mosquito menace etc. in the downstream c) Flow regulation for the augmentation of flow in the river 11) Effects on groundwater recharge . 12) Effects of periodic inundation or a fluctuating shoreline of impounded water a) Adverse effects on wildlife b) Adverse effects on nearby vegetation c) Decreased aesthetics at low reservoir storage. Sd- Plant - Water Appendix 1.2 :Important Statlsttcs of Indian Rtver Basins RetPtionahip in Irrigation (A): Discharge Available from Major River Basins

Name of River Len@ of Area AnnualAverage hver . Discharge Orm) (sq km) *cum)

The Indus ' 1,114 (468,068) (207,800) 321,289 41,955 I

Brahmapu tra Barak and other rivers Sabannathi ~ahi ~&mada . Tapti 724 65,145 17,982 I I I I Subamarekha 395 19.296 7.940 I Brahmani 799 39.033 18,310 Mahanadi 85 1 141,589 66,640 Godavari 1465 312,812 1OS,OOO Krishna 597 258,948 67,675

Cauvery 800 87,900 20,950 Total 2,528,084 143,945 -- , . (B): Discharge of Medium Rivers in India

Name of River Source Area Average (sq km) Discha e (Mm% WEST FLOWING:

Aj i Gujarat 106 2,139 N.A. Ozat Kathiwar 128 3.189 N.A. Shetrunji Village of Dalkahrania 182 5.514 280 Bhadar Rajkot Distt. 198 7.094 350 Dhadhar Panchmahal Distt. 135 2,770 690 Burhabalang Mayurbhank Distt. 164 4,837 2.177 Bantarani Keonjhar Distt. 365 12.789 5,755 Puma Dhulia Distt. 142 2.431 1.093 Ambica Dangs Ilistt. 142 2.715 1,247 Vaitama Nasik Distt. 126 2,572 4,350 Ulhas Poona Ilistt. 122 4,637 3,014 Savitri Kolaba Distt. 80 2.257 1,467 Mandavi Belgaum Distt. 87 2,032 1,320 Washishti 48 2.239 N.A. Kalinadi Belgaum Distt. 153 5,179 6,537 Gangavas or Bedti Dharwar 152 3.902 4.925 (in upper reaches) Sharavathi Shimoga 122 2.209 4.545 Netravati Canara 103 3,657 4,615 Chhar or Bey ore Elamtalvi Hills 169 2.788 5,200 Bharatpazha Palso Anamalai Hills 25 1 5.397 8,800 known as Poonami) Periyar Sivajini Hills 228 5,243 12.300 Pamba - 177 1.96 1 6,300 EAST FLOWING: Burhabalang Orissa 164 4,837 N.A. Baitarani Orissa 365 12.789 N.A. Bahuda Orissa 73 1,248 N.A. Rushikulya Phulbani Distt. 146 7.753 1,800 Varmsadhara Phulbani 22 1 10,830 3,500 Nagavali Kalahandi 217 9,410 2,400 Sarda Vizag Distt. 104 2,725 700 ' Yeleru Vizag Distt. 125 3,809 900 Vogarivagu Andhra Pradesh 102 1.348 N.A. Gundalakamma Karnool Distt. 220 8,494 1,ooo Musi Nellore Distt. 112 2,219 260 Paleru Nellore Distt. 104 2,483 300 Muneru Nellore Distt. 122 3,734 450 Swamarnukhi Palka 130 3,225 500 Kandateru Velikonda Distt. 73 3.534 420 Karotaliyar Chinglepet 13 1 3,521 350 Palar (including Kolar Ilistt. 348 17,87 1 1.780 Tributary Cheyyar) Gingee North Arcot. 94 3.044 300 Ponnaiyar Kolar Distt. 396 16.019 1,600 Varahanadi Tamil Nadu 94 3,044 N.A. Vellar Chithri Hills 193 8,558 850 Vaigai Madurai Distt. 258 7,74 1 770 Varshalli Madurai Distt. 125 3,104 3 10 Gundar Madurai Distt. 146 4.838 480 Vaippar Tirunilveli Distt. 130 5,288 520 Tamaraparam Tirunilveli C'istt. 130 5,482 1,370 FLOWING INTO OTHER COUNTRIES Kamaphali Mizoram 144 3.999 2,600 Kaldan Mizoram 290 7.933 5,160 Imp ha1 Mizoram - 7,255 4.7 16 Tixu Nanitaluk Nagaland 148 6.449 4,200

River Basins Total Rungff Percentage (biion m ) 14 major river basins (A pendix 1.2 A) 1406 85 .O 44 medium river basins rwhich do not 112 - 7.0 include last four in the above list) Minor rive? basins 117 7.4 ,Desert river basins 10 0.6 Total 1645 100.0