Tank Irrigation in Semi-Arid Tropical India Economic Evaluation and Alternatives for Improvement Abstract Resume

von Oppen, M . , and Subba Rao, K.V. 1987. Tank Irrigation in von Oppen, M. et Subba Rao, K.V. 1987. (Reseaux d'irrigation a Semi-Arid Tropical India: Economic Evaluation and Alterna- petits reservoirs dans les zones tropicales semi-arides de tives for Improvement. Research Bulletin no. 10. Patancheru, I'lnde. Evaluation economique et possibilites d'ameliora- A.P. 502 324, India: International Crops Research Institute for tion). Tank Irrigation in Semi-Arid Tropical India: Economic the Semi-Arid tropics. Evaluation and Alternatives for Improvement. Research Bulletin no. 10, Patancheru, A.P. 502 324, India: International Crops A survey of 32 tanks and farm data from Andhra Pradesh and Research Institute for the Semi-Arid Tropics. Maharashtra states was used to assess the economic performance of irrigation tanks in S A T India. District data on cli- L'etude de 32 reservoirs se trouvant dans les Stats d'Andhra matic and Institutional variables were used to analyze the Pradesh et de Maharashtra ainsi que l'analyse des donn6es agri- factors affecting tank-irrigation density. coles provenant de ces regions ont permis d'evaluer la perfor- Results indicate that the spatial distribution of irrigation mance economique de petits reservoirs d'irrigation dans les zones tanks is determined primarily by physical factors—hard rock tropicales semi-arides de I'Inde. La repartition regionale de ces substratum, postmonsoon rains, low moisture-holding capacity reseaux d'irrigation dans ces zones a ete expliquee a l'aide de of soils—and by population density. donnees sur les variances g6ographiques, climatiques et institu- Tank irrigation, formerly a source of relative stability, has tionnelles obtenues au niveau des districts. become a source of instability for agricultural production in Les resultats montrent que I'existence des reservoirs d'irriga- many parts of India. Important factors for the decline in tank tion est determinee essentiellement par des facteurs physiques irrigtion are: environmental degradation such as deforestation, (substrats en roche dure, les pluies apres la saison pluviale, une soil erosion, siltation, tankbed cultivation, and lack of adminis- capacite maximum pour l'eau peu elevee) et par la densite trative setup to provide timely repair and maintenance of tanks, demographique. and to ensure proper water control and tank management. Le systeme d'irrigation avec petits reservoirs, source de sta- Simulation results show that with improved water control bilite relative dans le temps, est devenu maintenant une source and by keeping sluices closed on rainy days, a 20% larger d'instabilite" notable pour la production agricole dans plusieurs command area can be irrigated. A Tank Irrigation Authority is parties de ITnde. Les facteurs importants qui influencent le declin proposed for better water control and management. Another de ce systeme sont : la degradation de l'environnement telle que la concept proposed is Composite Watershed Management on deforestation, l'erosion des sols, I'envasement, ['exploitation au Alfisols involving a system of runoff- and erosion-controlling fond des reservoirs et enfin, le manque d'une infrastructure land management for enhanced groundwater recharge and sus- administrative susceptible de garantir l'entretien et la reparation tained well irrigation. This concept, analyzed at I C R I S A T des reservoirs en temps utile et d'assurer l'exploitation efficace Center in a modeling exercise, has considerable economic des reservoirs visant a la bonne conduite des eaux. potential. Les resultats de la simulation montrent que la conduite ame- lioree des eaux et la fermeture des vannes les jours de pluies permettent d'augmenter de 20% la superficie asservie. On pour- rait envisager la creation d'un Service d'irrigation a petits reservoirs dans le but d'assurer une rneilleure conduite des eaux et une meilleure exploitation des reservoirs actuels. Cependant, il est peu certain que ce Service d'irrigation soil a meme de retourner la tendance des reservoirs qui cedent a la pression demographique sur la terre. Un autre concept est egalement propose : amenagement des bassins versants composites sur les Alfisols. lls'agit d'un systeme d'amenagement des terres comprenant le controle du ruissellement et de l'erosion permettant ainsi l'alimentation arnelioree de la nappe d'eau et l'irrigation par puits continue. Analyse au Centre ICRISAT dans un essai de moderation, ce concept s'avere tres prometteur sur le plan economique.

Cover: Satellite views of tank-irrigated areas in southern India. Shallow, sedimented tanks arc shown in blue, and deep, clear-water tanks are black. Cropland appears in dark and light red. (Courtesy of the National Remote Sensing Agency, Hyderabad, India.) Tank Irrigation in Semi-Arid Tropical India Economic Evaluation and Alternatives for Improvement

M. von Oppen and K.V. Subba Rao

ICRISAT Research Bulletin no. 10 International Crops Research Institute for the Semi-Arid Tropics Patancheru, Andhra Pradesh 502 324, India 1987 About the Authors

M. von Oppen: Previously Program Director, Resource Management Program, I C R I S A T . Presently Professor in Agricultural Marketing, Institute of Agricultural Economics and Social Sciences in the Tropics, University of Hohenheim, Institut 490, postfach 700562, D-7000, Stuttgart 70, Federal Republic of Germany.

K. V. Subba Rao: Senior Research Associate, Resource Management Program, I C R I S A T .

Publication Editor

Madhu Reddy: Previously Editor, Information Services, ICRISAT. Presently at Orient Longman Ltd., 5-9-41/1, Bashirbagh, Hyderabad-29, India.

The International Crops Research Institute for the Semi-Arid Tropics is a nonprofit scientific educational institute receiving support from donors through the Consultative Group on International Agricultural Research. Donors to ICRISAT include governments and agencies of Australia, Belgium, Canada, Federal Republic of Germany, Finland, France, India, Italy, Japan, Mexico, Netherlands, Nigeria, Norway, People's Republic of China, Sweden, Switzerland, United Kingdom, United States of America, and the following international and private organizations: Asian Development Bank, Deutsche Gesellschaft fur Technische Zusammenarbeit (GTZ), Global 2000 Inc., International Development Research Centre, International Fertilizer Development Center, International Fund for Agricultural Development, The European Economic Community, The Ford Foundation, The Leverhulme Trust, The Opec Fund for International Development, The Rockefeller Foundation, The World Bank, United Nations Development Programme, and the University of Hohenheim. Information and conclusions in this publication do not necessarily reflect the position of the aforementioned governments, agencies, and international and private organizations.

Correct citation: von Oppen, M., and Subba Rao, K.V. 1987. Tank Irrigation in Semi-Arid Tropical India: Economic Evaluation and Alternatives for Improvement. Research Bulletin no. 10. Patancheru, A.P. 502 324, India: International Crops Research Institute for the Semi-Arid Tropics. Contents

1. Introduction 5 Irrigation in India 5 Decline of Tank Irrigation 5 Objectives of this Report 5

2. History and Development of Tank Irrigation 7 Historical Records on Tank Irrigation 7 Development of Tank Irrigation Over Time 8 Factors Affecting Regional Distribution of Irrigation Tanks 10 Summary 11

3. Economics of Existing Tank Irrigation 12 Tanks Selected for Farm Surveys 12 Technical Features Determining Costs and Performance of Irrigation Tanks 12 Benefits, Costs, and Benefit-Cost Comparisons of Existing Tank Irrigation 15 Summary 25

4. Deterioration of Tank Irrigation and Need for Remedial Action 25 Tank Irrigation as a Source of Instability 25 Reasons for Decline in Tank Irrigation 27 Remedial Action for the Improvement of Tank Irrigation 27 Summary 29

5. Alternatives for Improving Tank Irrigation 30 The Concept of a Tank Irrigation Authority 30 Composite Watershed Management on Alfisols 34 Summary 35

6. Summary and Conclusions 36

7. References 37

8. Appendix 38 ACKNOWLEDGEMENTS

This research b u l l e t i n summarizes the results of eight years' research on different aspects of t a n k i r r i g a t i o n in the I n d i a n S e m i - A r i d T r o p i c s ( S A T ) . M o s t of the material presented here is taken f r o m o u r earlier reports listed below:

- v o n O p p e n , M., and Binswanger, H.P. 1977. I n s t i t u t i o n a l and physical factors affecting t a n k i r r i g a t i o n density in I n d i a . Presented at the 17th A n n u a l Conference of the I n d i a n E c o n o m e t r i c Society, 19 -21 D e c 1977, T r i v a n d r u m , K e r a l a , I n d i a . - v o n O p p e n , M. 1978, Instability of area and p r o d u c t i o n under t a n k i r r i g a t i o n in selected districts of A n d h r a Pradesh a n d T a m i l N a d u . Economics P r o g r a m Discussion Paper no. 9. Patancheru, A.P. 502 324, India; International Crops Research Institute f o r the S e m i - A r i d Tro p i c s. ( L i m i t e d d i stribution.) - v o n O p p e n , M . , and Subba R a o , K. V. 1980. T a n k i r r i g a t i o n in semi-arid tropical India. Part I. Historical development and spatial distribution. Economics Program Progress R e p o r t no.5. Patancheru, A . P . 502 324, I n d i a : Interna- t i o n a l Crops Research Institute f o r the S e m i - A r i d Tropics. (Limited distribution.) - v o n O p p e n , M . , and Subba R a o , K. V. 1980. T a n k i r r i g a t i o n in semi-arid tropical India. Part II. Technical features a n d economic performance. Economics P r o g r a m Progress R e p ort no. 8. Patancheru, A.P. 502 324, India: Interna- t i o n a l Crops Research Institute f o r the S e m i - A r i d Tropics. (Limited distribution.) - v o n O p p e n , M . , and Subba R a o , K . V . 1982. H i s t o r y and economics of tank i r r i g a t i o n in semi-arid t r o p i c a l I n d i a . Pages 54-75 in Proceedings of the S y m p o s i u m on R a i n W a t e r and D r y l a n d A g r iculture, 3 Oct 1980, New Delhi, India. N e w D e l h i , India: I n d i a n N a t i o n a l Science A c a d e m y . - V e n k a t r a m , B.R. 1985. A d m i n i s t r a t i v e feasibility of a T a nk Irrigation Authority. Economics Program Consultant's Report. Patancheru, A.P. 502324, India: International Crops Research Institute f o r the S e m i - A r i d Tro p i cs. ( L i m i t e d distribution.) - v o n O p p e n , M., Subba R a o , K.V., and Engelhardt, T. 1983. Alternatives for improving small scale irrigation systems in Alfisols watersheds in India - a p o s i t i o n paper. Presented at the University of Minnesota/Colorado University/ U S A I D W o r k s h o p o n W a t e r M a n a g e m e n t a n d Policy, 13-15 Sep 1983, Khon Kaen, Thailand. Patancheru, A.P. 502324, India: International Crops Research Institute f o r the S e m i - A r i d Tro p i cs. ( L i m i t e d d i s t r i b u t i o n . )

T h e authors gratefully acknowledge the c o n t r i b u t i o n s made by M r . H.S. S a n d h u in collecting data and developing some of the methodologies used in this study, and M r . B.R. V e n k a t r a m f o r his report on a d m i n i s t r a t i v e feasibility of a t a n k i r r i g a t i o n a u t h o r i t y . T h a n k s are also due to M r . T. H a n u m a n t h a R a o f o r reviewing earlier parts of this paper and to D r s . J . G . R y a n , T . S . W a l k e r , N.S. J o d h a , and V . S . D o h e r t y f o r their critical c o m m e n t s o n earlier drafts o f this study. W e also thank all the reviewers f o r their useful suggestions. We are grateful to Dr. J.S. Kanwar, Director of Research, I C R I S A T , w h o t o o k interest in c o n d u c t i n g this research. H o w e v e r , the responsibility f o r any shortcomings rests solely w i t h the authors.

M. von Oppen K.V. Subba Rao 1. Introduction

Irrigation in India Decline of Tank Irrigation

I r r i g a t i o n is vital to the I n d i a n e c o n o m y as it helps to S m a l l water reservoirs behind earthen dams are called relieve agriculture f r o m its dependence on the m o n s o o n tanks in I n d i a ( S h a r m a 1981). T a n k s supply many, v i l - rains. Farmers w i t h access to i r r i g a t i o n can stabilize and lages w i t h d r i n k i n g water, but their p r i m a r y purpose is increase f a r m p r o d u c t i o n ; risks of c r o p failure can be i r r i g a t i o n . T a n k i r r i g a t i o n is an established practice in reduced and opportunities increased f o r m a k i n g f u l l use most of the semi-arid tropics ( S A T ) of I n d i a and of some of i m p r o v e d seed and fertilizer. At present a b o u t 2 8 % of other countries. In I n d i a , the m o n s o o n rains f a l l errati- India's cultivated land is under i r r i g a t i o n . cally d u r i n g a few m o n t h s of the year, and i r r i g a t i o n I r r i g a t i o n systems in I n d i a are categorized f o r a d m i n i s - tanks serve to store and regulate waterflow f o r a g r i c u l t u - trative purposes i n t o m a j o r , m e d i u m , and m i n o r irriga- ral use. In southern I n d i a tanks are used p r i m a r i l y f o r rice t i o n w o r k s . M a j o r i r r i g a t i o n w o r k s are generally b u i l t o n c u l t i v a t i o n . T h u s tank i r r i g a t i o n is a water- management perennial rivers, and constitute large dams and canals technology that is ideally suited to the S A T , where p r o v i - that irrigate areas of many thousand hectares. M e d i u m sion of a continuous f l o w of water w i t h l o w m i n e r a l irrigation w o r k s constitute reservoirs of r u n - o f f water, or content permits uninterrupted rice c u l t i v a t i o n year after the so called " l a r g e " tanks. M i n o r i r r i g a t i o n w o r k s year, w i t h o u t ever exhausting or salinifying the soil. include all surface and g r o u n d w a t e r sources w h i c h cost H o w e v e r , despite these advantages the tank-irrigated below Rs 2.5 m i l l i o n per project. Table 1 presents the area area in I n d i a over the past t w o decades has tended to in I n d i a irrigated by m a j o r a n d m e d i u m i r r i g a t i o n sour- stagnate and f a l l . F r o m a source of relative stability, tank ces in c o m p a r i s o n to m i n o r i r r i g a t i o n f r o m surface and i r r i g a t i o n has become m o r e and m o r e unreliable; in m a n y g r o u n d w a t e r sources. areas tank i r r i g a t i o n n o w is a source of increasing insta- Each of these three types of i r r i g a t i o n sources evolved bility in agricultural production. at different times in history to meet man's changing requirements f o r irrigated land and as technologies developed for storing, t r a n s p o r t i n g , and l i f t i n g water. W h i l e i r r i g a t i o n f r o m tanks and d u g wells is a c o m p a r a t i v e l y old Objectives of this Report technology, canal and borewell irrigation with electric- or diesel-powered pumps are relatively recent innovations. These observations p r o m p t e d us to study the factors Figure 1 shows the area irrigated by different sources in c o n t r i b u t i n g to this development and to d r a w inferences I n d i a . These i r r i g a t i o n sources vary in i m p o r t a n c e in that w o u l d p o i n t to future action. T h e study is based on a different regions, depending u p o n factors such as t o p o - survey of 32 surface i r r i g a t i o n tanks spread across the graphy, technology, local administration, and altitude. states of A n d h r a Pradesh and Maharashtra ( A p p e n d i x 1).

Table 1. Gross area irrigated by major and medium and minor irrigation sources in India, 1950-51 to 1977-78.

Gross area irrigated ('000000 ha)

Source 1950-51 1960-61 1968-69 1973-74 1977-78

Major and medium irrigation 9.7 14.3 18.1 20.7 25.0 ( 42.9)1 ( 49.3) ( 48.1) ( 45.8) ( 46.5)

Minor irrigation Surface 6.4 6.4 6.5 7.0 7.8 ( 28.3) ( 22.1) ( 17.3) ( 15.5) ( 14.5) Groundwater 6.5 8.3 13.0 17.5 21.0 ( 28.8) ( 28.6) ( 34.6) ( 38.7) ( 39.0)

Total 22.6 29.0 37.6 45.2 53.8 (100.0) (100.0) (100.0) (100.0) (100.0)

1. Figures in parentheses indicate percentage area irrigated by different sources. Source: 37th All India Agricultural Economics Conference—Presidential Address by M.S. Swaminathan, 1977.

5 55

50 Gross irrigated area

40 Net irrigated area 35

30 Wells

15 Canals

5 Tanks

Other sources 0

Period

Figure 1. Area irrigated by different sources in India.

T h e report has f o u r objectives. izes the factors w h i c h determine the regional d i s t r i b u t i o n 1. To explain the geographical d i s t r i b u t i o n of t a n k irriga- of i r r i g a t i o n tanks in I n d i a . In the t h i r d chapter the t i o n i n I n d i a . economics of tank irrigation is analyzed. T h e f o u r t h 2. To measure the economics of t a n k i r r i g a t i o n . chapter shows h o w at the all I n d i a level, tank i r r i g a t i o n 3. To explore the physical and administrative factors expanded u n t i l the early 1960s, subsequently became affecting the performance of irrigation tanks. stagnant, and presently declined at a rapid rate. The 4. To propose ways to i m p r o v e t a n k i r r i g a t i o n or alterna- reasons f o r this decline are examined. We present in the tive watershed-management systems in I n d i a . f i f t h chapter t w o viable concepts f o r i m p r o v i n g tank- water management on Alfisols. The final chapter sum- T h e second chapter presents a brief account of the marizes the findings and conclusions emerging f r o m the historical development of tank i r r i g a t i o n a n d s u m m a r - previous chapters.

6 2 . H i s t o r y a n d D e v e l o p m e n t o f T a n k I r r i g a t i o n

Historical Records on Tank Irrigation W h i l e studying the c u l t u r a l e c o n o m y o f i r r i g a t i o n i n southern Tamil Nadu, Ludden (1978) observed that tank In the southern states of S A T I n d i a , tank i r r i g a t i o n sys- construction in the past played a key role in the r i t u a l - tems have existed since Vedic times. T w o tanks are m e n t i - based system of entitlement to c o n t r o l land resources. oned in the R a m a y a n a : the L a k e of Five N y m p h s T h r o u g h the c o n s t r u c t i o n of a t a n k the local chief gener- (Panchapsarotataka), associated with Mandkarni or Sat- ated resources f o r d o n a t i o n s to temples, w h i c h in t u r n k a r n i ; a n d the Pampasaras, w h i c h is apparently the same b r o u g h t h i m the support o f the B r a h m i n s . " T h e i r r i g a t i o n as Pampasagar, a tank in Huvimothadagalli taluk, Bel- system as a whole grew in a cellular segmented manner: lary district, on the T u n g a b h a d r a river ( Y a z d a n i 1960). similar, allied but staunchly independent units were There are references to t a n k - i r r i g a t i o n practices in early merely added on as p o p u l a t i o n and irrigated area I n d i a n records d a t i n g back to m a n y centuries before the increased. It was this system—within which irrigation C h r i s t i a n Era. M a n y of the tanks f o u n d in southern I n d i a facilities were constructed, maintained, and regulated by have been in existence for several generations — t w o in the same organizational units that c o n t r o l l e d c u l t i v a t i o n C h i n g l e p u t D i s t r i c t are referred to in inscriptions of the processes as a w h o l e — t h a t c o n f r o n t e d British a d m i n i s - 8th and 9th centuries ( H a r r i s 1923). trators in the nineteenth c e n t u r y " ( L u d d e n 1978). I n the Telengana region o f A n d h r a Pradesh, k n o w n f o r T h e British were highly impressed by the extent of t a n k rice cultivation, tank irrigation developed extensively i r r i g a t i o n in the c o u n t r y . In 1853, R. Baird S m i t h since ancient times. T h e districts of W a r a n g a l a n d K a r i m - observed that " T h e extent to w h i c h t a n k i r r i g a t i o n has nagar have several old i r r i g a t i o n tanks; the lakes of P a k - been carried t h r o u g h o u t a l l the irrigated region of the h a l , R a m a p p a , L a k n a v a r a m , and Sanigaram were M a d r a s Presidency is t r u l y e x t r a o r d i n a r y . An imperfect constructed in the 12th and 13th centuries by kings of the record of the n u m b e r of tanks in the 14 districts shows period ( A l l I n d i a E c o n o m i c Conference 1937). There is a them to a m o u n t to not less t h a n 43,000 in repair a n d system of tanks at K a t t a g i r i referred to in inscriptions 10,000 out of repair or 53,000 in a l l " ( S m i t h 1856). dated 1096 A D . These accounts describe the practice of Some 30 years later, t a n k - i r r i g a t i o n statistics were constructing tanks in a series at different levels of a assembled, and a list of tank-irrigated areas ( M a n u a l of watershed. In 1188 A D , a merchant named Dasi-Setti A d m i n i s t r a t i o n of the M a d r a s Presidency, 1885) in the renovated and increased the size of a t a n k at Banavur. In districts of the M a d r a s Presidency f r o m 1882 to 1883 1201/02 A D , after a famine in T i r u v a n n a m a l a i village, gave a figure of 32000 non-private tanks. W h e n c o m p a r - t w o persons built a tank in m e m o r y of their m o t h e r ing the net areas irrigated by these tanks in 1882-83 w i t h (Appadorai 1936). A Somavaram inscription dated 1213 areas irrigated by all tanks (i.e., i n c l u d i n g the f o r m e r l y AD states that one Racherla Beti Reddi constructed t w o private tanks) in 1969-72 (Table 2) we f i n d that in the tanks. A n u m b e r of inscriptions dated a r o u n d the 11th entire area f o r w h i c h this i n f o r m a t i o n is available, the and 12th centuries describe t a n k - c o n s t r u c t i o n activities extent of tank i r r i g a t i o n today is a b o u t the same as it was in W a r a n g a l ( G o p a l Reddy 1973). a century ago. T a n k - i r r i g a t e d area has decreased in t w o Several southern rulers t o o k an interest in tank c o n - regions i n c l u d i n g the districts of (1) A n a n t a p u r , K u r n o o l , struction. T h e K e s a r i - T a t a k a m T a n k was built by P r o l a I Cuddapah, and Bellary, and (2) Salem, Coimbatore, and of the Kakatiyas. Beta II constructed t w o tanks, Setti- M a d u r a i . O n the other h a n d , t a n k i r r i g a t i o n has Kere and Kesari-Samundra. A n o t h e r K a k a t i y a ruler, increased in t w o other regions, i.e., (1) V i z a g , K r i s h n a , Prola II, built two tanks. The Pratapa-Charitra states and Nellore, and (2) Chingleput, North Arcot, South that the ruler Ganapatideva built tanks at N e l l o r e , G a n - Arcot, Thanjavur, Tirunelveli, and Tiruchirapalli. g a p u r a m , Ellore, G a n a p a p u r a m , and Ekasilanagaram The overall area under n o n - p r i v a t e tanks was reported ( Y a z d a n i 1960). to be 785 000 ha in 1882-83, while the area irrigated f r o m A rock inscription dated 1030 AD praises the local all tanks in 1969-72 was 930 000 ha. This difference is n o t ruler K o t a G o n k a for the m a n y tanks built by h i m very large a n d if the private tanks, excluded f r o m the (Vaidehi Krishnamurty 1970). An inscription from the earlier figures, could be accounted f o r (the present figures Sorali t a l u k i n Shimoga district, dated 1071 A D m e n - include all tanks), it can be concluded that in the f o r m e r tions that fresh land was b r o u g h t under c u l t i v a t i o n by the M a d r a s Presidency there has h a r d l y been any change in c o n s t r u c t i o n of a new tank called Setti-kere ( D e p a r t m e n t the overall extent of tank i r r i g a t i o n d u r i n g the last 100 of Information and Public Relations, Hyderabad, 1953). years. O f t e n tanks were donated to temples, and tank income In contrast to the m a r g i n a l change in t a n k - i r r i g a t e d was used f o r temple maintenance. area in the f o r m e r M a d r a s Presidency, the t o t a l c r o p p e d

7 Table 2. Area irrigated by tanks, and total cropped area in the region of the old Madras Presidency, 1882-83 and 1969-72.

1882-83 Average for 1969-72

Total Net area Total Net area cropped irrigated cropped irrigated (3) (4) area by tanks area by tanks District ('000 ha) ('000 ha) (1) (2)

(1) (2) (3) (4) (5) (6) Anantapur 46 36 910 32 19.8 0.9 Cuddapah 97 76 462 17 4.7 0.2 Kurnool 29 16 1303 13 44.5 0.8 Bellary 29 21 610 8 21.0 0.4 Krishna 116 16 672 36 5.8 2.3 Nellore 91 61 666 92 7.3 1.5 Vishakapatnarn 19 12 529 89 27.4 7.3 Salem 75 39 924 32 12.3 0.8 Coimbatore 57 18 837 5 14.6 0.3 Madurai 94 64 648 53 6.9 0.8 Chingleput 174 127 433 164 2.5 1.3 North Arcot 137 81 643 105 4.7 1.3 South Arcot 161 86 723 108 4.5 1.3 Thanjavur 42 18 875 30 20.8 1.6 Tirunelveli 152 59 557 76 3.6 1.3 Tiruchirapalli 100 53 822 79 8.2 1.5

Total 1421 785 11614 939 8.2 1.2 Source: Tamil Nadu Season and Crop Reports, 1969-72.

area in the region increased about eight times d u r i n g the ever, as is s h o w n below, in the long r u n it is not only last century. T h u s , while tank i r r i g a t i o n was available f o r institutional factors but also population-density factors over 5 0 % of the total cropped area in the past, it is that influence tank development. Differences in develop- available n o w to less than 10% of the t o t a l c r o p p e d area. ment of tank i r r i g a t i o n over time can be largely explained Even t h o u g h other sources of i r r i g a t i o n have become by these variables. a v a i l a b l e - n o w canals and wells, f o r instance, irrigate a p p r o x i m a t e l y another 10% each in this area—the over- Development of Tank Irrigation over all cropped area under i r r i g a t i o n has fallen f r o m 5 0 % to Time a b o u t 30%. In contrast to the situation in the old M a d r a s Presid- ency, there is evidence that tank i r r i g a t i o n in the old There is evidence that this method of u t i l i z i n g r u n o f f H y d e r a b a d State is of m o r e recent o r i g i n . T h e area i r r i - water is deeply rooted in I n d i a n culture and some tanks gated f r o m tanks increased considerably o n l y d u r i n g the have inscriptions d a t i n g back a m i l l e n i u m or more. His- latter part of the 19th century, under the Nizams of torians and anthropologists have pointed out that there is H y d e r a b a d . F r o m 4000 ha in 1895-96, records of the a dialectic relationship between p o p u l a t i o n and tank i r r i - Public W o r k s D e p a rt me n t ( P W D ) o f the H y d e r a b a d g a t i o n , one reinforcing the other ( L u d d e n 1978). State show a r o u n d 40000 ha of t a n k - i r r i g a t e d area However, the relationship between population density a r o u n d the t u r n of the century, and a r o u n d 350000 ha and the intensity of tank i r r i g a t i o n is not necessarily some 40 years later. No estimate is made in the sources of linear, i.e., at different levels of p o p u l a t i o n density the these statistics about the n u m b e r of private tanks that g r o w t h of tank-irrigated area may vary. I n i t i a l l y , where must have existed. T h e fact that the P W D of H y d e r a b a d physically feasible and economically attractive, tank i r r i - State expanded the tank-irrigated area d u r i n g the t u r n of gation systems are expanded till the p o p u l a t i o n density the century, while the British G o v e r n m e n t in the M a d r a s crosses a threshold level. Beyond this level f u r t h e r p o p u - Presidency d i d not do so, indicates that t a n k - i r r i g a t i o n lation pressure m a y tend to adversely affect the existing intensity in different areas was to some extent influenced t a n k - i r r i g a t i o n systems and special measures may be by the governments in those areas and their emphasis on required to preserve the capital invested in i r r i g a t i o n certain types o f capital-development p r o g r a m s . H o w - tanks.

8 T h e historical data on tank development in different T h e p r o p o r t i o n of tank-irrigated area as a percentage of states over the years indicate that the threshold density to net irrigated area in I n d i a declined f r o m 17% in 1950-51 begin intensive tank construction lies between 50 and 60 to 10% in 1978-79, whereas the well-irrigated area persons km"2 . T h e upper l i m i t is n o t clearly discernible -- increased f r o m 2 8 % to 4 3 % of net irrigated area d u r i n g it seems to vary f r o m one region to another — but there is the same p e r i o d . T a n k i r r i g a t i o n decreases w i t h an clearly a decline in t a n k i r r i g a t i o n at very h i g h levels of increase in p o p u l a t i o n ; at the same t i m e canal and well p o p u l a t i o n density. F o r instance, in I n d i a as a w h o l e , the i r r i g a t i o n expand rapidly. absolute area irrigated by tanks increased f r o m a b o u t 3.5 The development of tank irrigation in India after inde- m i l l i o n ha in 1945-50 to over 4.5 m i l l i o n ha in 1960-70; it pendence was also influenced by other factors that are fell to less t h a n 4 m i l l i o n ha f r o m 1973 o n w a r d s ( T a b l e 3), related, t h o u g h perhaps not directly a t t r i b u t a b l e t o , p o p - w h e n the r u r a l p o p u l a t i o n density in I n d i a increased to u l a t i o n density. A b o l i t i o n o f ownership rights f o r private m o r e t h a n 135 persons k n r2 f r o m 100 persons k n r2 in tanks stopped private investment in t a n k i r r i g a t i o n soon 1960. T h e three southern states of A n d h r a Pradesh, after independence. This also decreased the efficiency of T a m i l N a d u , and K a r n a t a k a c o n t r i b u t e m o r e t h a n 6 0 % water c o n t r o l and tank management. On the other h a n d , o f the tank-irrigated area i n S A T I n d i a . T h e t a n k - public campaigns were launched to increase f o o d p r o d u c - irrigated area f o r m s a r o u n d 3 0 % of the net irrigated area. t i o n ; and tank b u i l d i n g was one of the activities v i g o r -

Table 3. Growth of tank irrigation in India.

Total Net Well- Tank- Tank-irrigated Tank-irrigated Well-irrigated cropped irrigated irrigated irrigated area to total area to net area to net area area area area cropped area irrigated area irrigated area Year ...... ('000 000 ha)...... (%) (%) (%) 1950-51 131.9 20.9 5.9 3.6 2.7 17.2 28.2 1951-52 133.4 21.0 6.5 3.4 2.5 16.2 30.9 1952-53 137.5 21.2 6.6 3.2 2.3 15.1 31.1 1953-54 142.3 21.7 6.7 4.1 2.9 18.9 30.9 1954-55 144.0 21.9 6.7 4.0 2.8 18.3 30.6

1955-56 146.7 22.8 6.7 4.4 3.0 19.3 29.4 1956-57 149.1 22.5 6.2 4.5 3.0 20.0 27.6 1957-58 145.4 23.2 6.8 4.5 3.1 19.4 29.3 1958-59 150.8 23.4 6.7 4.8 3.2 20.5 28.6 1959-60 152.1 23.8 6.9 4.7 3.1 19.7 29.0

1960-61 152.3 24.6 7.3 4.6 3.0 18.7 29.7 1961-62 156.2 24.9 7.3 4.6 2.9 18.5 29.3 1962-63 156.8 25.7 7.6 4.8 3.1 18.7 29.6 1963-64 157.0 25.9 7.8 4.6 2.9 17.8 30.1 1964-65 159.3 26.6 8.1 4.8 3.0 18.0 30.4

1965-66 155.3 26.7 8.7 4.4 2.8 16.5 32.6 1966-67 156.8 27.1 9.2 4.6 2.9 17.0 33.9 1967-68 163.0 27.5 9.3 4.6 2.8 16.7 33.8 1968-69 159.7 29.0 10.8 4.0 2.5 13.8 37.2 1969-70 163.9 30.3 11.1 4.4 2.7 14.5 36.6

1970-71 167.4 31.4 11.9 4.5 2.7 14.3 37.9 1971-72 164.2 31.9 12.2 4.1 2.5 12.3 38.2 1972-73 161.5 32.0 13.0 3.6 2.2 11.2 40.6 1973-74 169.5 32.5 13.2 3.9 2.3 12.0 40.8 1974-75 163.9 33.7 14.2 3.5 2.2 10.5 42.1

1975-76 171.0 34.5 14.3 4.0 2.3 11.6 41.5 1976-77 167.1 34.8 14.8 3.9 2.3 11.2 42.5 1977-78 172.3 36.7 15.7 3.9 2.3 10.6 42.8 1978-79 175.2 38.0 16.4 3.9 2.2 10.3 43.2

Source: Indian Agriculture in Brief, Government of India, Ministry of Agriculture.

9 ously pursued in such campaigns u n t i l the late 1950s. N a d u , i n Telengana, the coastal districts o f A n d h r a P r a - Subsequently, the availability of diesel- and electric- desh, in south-central Karnataka, and in eastern powered pumps made well water m o r e attractive as an V i d a r b h a . I n n o r t h e r n I n d i a , there are t w o pockets that alternative, privately controlled source for irrigation . show a h i g h density of t a n k i r r i g a t i o n : northeastern U t t a r Resources were shifted f r o m the development of tanks Pradesh, i n the area o f the f o r m e r k i n g d o m o f O u d h , and towards wells, leading to a massive expansion of well Rajasthan, east of the Aravalli mountain range. Apart i r r i g a t i o n . F u r t h e r , reluctance of the policy makers to from physical factors and population density, it appears raise the water rates made it m o r e a n d m o r e d i f f i c u l t f o r that i n s t i t u t i o n a l factors have also played a role in deter- the P W D to acquire funds to cover the increasing costs of m i n i n g tank d i s t r i b u t i o n . A m a p s h o w i n g the t e r r i t o r y maintenance and repair. T a n k i r r i g a t i o n , f o r m e r l y consi- under British and princely rule in 1890 indicates that tank dered an economically productive and p r o f i t a b l e under- i r r i g a t i o n was p r o m o t e d more under princely rule than t a k i n g , began to be neglected a n d was o n l y half-heartedly under British rule (Figure 3). supported by policy makers and planners. T h e resulting We evaluated the factors affecting regional distribu- decrease in efficiency a n d reliability of the performance t i o n of i r r i g a t i o n tanks using data f r o m 165 districts in of i r r i g a t i o n tanks tended to create the impression that S A T I n d i a in a regression analysis ( v o n O p p e n and tank i r r i g a t i o n was inferior to other types of i r r i g a t i o n . Subba R a o 1980). This analysis showed that b o t h in the f o r m e r princely and British areas, physical factors such as hard rock Factors Affecting Regional substratum, annual average humidity, postmonsoon rainfall, total rainfall, and low soil moisture-holding Distribution of Irrigation Tanks capacity encouraged tank i r r i g a t i o n . Such factors e x p l a i n about 5 0 % of the v a r i a t i o n in tank-irrigated area. A l t h o u g h runoff-collection tanks exist in nearly every F u r t h e r m o r e , the study showed that in the f o r m e r I n d i a n district, t a n k - i r r i g a t i o n density varies considera- princely areas ( b u t not in the f o r m e r British areas) the bly f r o m district t o district. Presently, i n the I n d i a n S A T influence of p o p u l a t i o n on tank i r r i g a t i o n was measura- ( F i g u r e 2), tanks are concentrated in the southern and ble, e x p l a i n i n g another 2 0 % of the v a r i a t i o n in tank central regions, i.e., in the coastal districts of T a m i l density. Keeping all other variables constant, the f o l l o w -

Figure 2. Tank-irrigation density in SAT India. Figure 3. British and princely territories in 1890.

10 2

1.5

0.5

25 75 100 150 200 250 300 Population density (km-2)

Figure 4. Tank irrigation as a function of population density in districts formerly under princely rule (physical factors remaining constant).

ing observations were made: as p o p u l a t i o n density in the by physical conditions such as hard rock substratum, f o r m e r princely states crossed the level of a b o u t 60 per- average h u m i d i t y , p o s t m o n s o o n r a i n f a l l , t o t a l r a i n - sons k m -2, density of tank-irrigated areas began to f a l l , and l o w soil m o i s t u r e - h o l d i n g capacity. H o w e v e r , increase, reaching a m a x i m u m at p o p u l a t i o n density of further study shows that in the f o r m e r princely areas a r o u n d 220 persons krrr2 (Figure 4), and d r o p p i n g w i t h the influence of p o p u l a t i o n density on t a n k i r r i g a t i o n further increase in p o p u l a t i o n density. F o r the f o r m e r is measurable, explaining another 2 0 % of the v a r i a t i o n British districts, there was no statistically significant rela- in tank density. It reveals that tank density increases tionship between p o p u l a t i o n and tank density. These when the p o p u l a t i o n density crosses 60 persons k m- 2 results i m p l y that the institutional e n v i r o n m e n t , to the and reaches the m a x i m u m w i t h a p o p u l a t i o n density extent that it differed between British and princely rule, of a r o u n d 220 persons k m - 2 in princely districts. Since had an influence on construction and maintenance of administration, organization, legal conditions, and i r r i g a t i o n tanks. In fact, this influence may still continue land tenure differed between British a n d princely rule, in the prevailing local customs of water c o n t r o l , tank tank i r r i g a t i o n as a manifestation of the economic management, and maintenance. interests of b o t h public a u t h o r i t y a n d private farmers was certainly affected and may still continue to be so. Generally, with the abolition of fuedal land-tenure Summary systems the small i r r i g a t i o n tanks became c o m m o n p r o p e r t y and suffered the typical fate of inefficient • Historical records give ample evidence of tank irriga- management. t i o n having been practiced f o r centuries in m a n y parts • The percentage of tank-irrigated area to net irrigated o f I n d i a . area in I n d i a fell f r o m 17% in 1950-51 to 10% in • A b o u t 6 0 % of the area irrigated by tanks is concen- 1978-79. Some of the reasons are: a b o l i t i o n of o w n e r - trated i n T a m i l N a d u , A n d h r a Pradesh, and ship rights on private tanks after independence, p o o r K a r n a t a k a . tank-water management, and the increased conven- • Statistical analysis of district data shows that spatial ience of well irrigation with the availability of electric- d i s t r i b u t i o n of tank i r r i g a t i o n is determined p r i m a r i l y and diesel-powered pumps.

11 3 . Economics o f Existing T a n k I r r i g a t i o n

To assess the economics of tank i r r i g a t i o n we require farmers w i t h irrigated areas above 0.5 ha.Those farmers i n f o r m a t i o n o n benefits f r o m t a n k i r r i g a t i o n a n d o n costs w h o owned less t h a n 0.5 ha were not included. o f c o n s t r u c t i o n and operation o f i r r i g a t i o n tanks. I n this Eight farmers were selected at random from the chapter we describe the technical features d e t e r m i n i n g r e m a i n i n g list f o r detailed investigation. If a f a r m e r was the economic performance of i r r i g a t i o n tanks and p r o - not available, the next farmer on the list was selected. vide estimates of benefits, costs, and benefit-cost c o m p a r - Benefits of tank i r r i g a t i o n were calculated on the basis of isons. Q u a n t i t a t i v e estimates are derived f r o m the returns f r o m tank-irrigated crops c o m p a r e d w i t h returns analysis of data collected in special surveys or f r o m from crops without irrigation (rainfed crops). secondary sources.

Data Collection Tanks Selected for F a r m Surveys Primary data on cropping activities, land utilization, A t o t a l of 32 tanks were surveyed. These were selected i n p u t - o u t p u t , etc., were collected on a recall basis f r o m the states of A n d h r a Pradesh, an area w i t h high through personal interviews using a pretested structured tank density, and M a h a r a s h t r a , an area w i t h l o w tank schedule. density. In A n d h r a Pradesh the f o l l o w i n g districts were T h e data obtained f r o m secondary sources ( i r r i g a t i o n chosen: M e d a k and M a h b u b n a g a r representing the Tele- and revenue departments) included 10 years' daily rain- ngana area w h i c h had been under princely rule ( N i z a m s fall for the selected taluks, water levels and actual area of H y d e r a b a d ) and was characterized by m e d i u m r a i n - irrigated f r o m tanks, c r o p p i n g patterns in the village, f a l l , red soils, and high tank density; and A n a n t a p u r and land revenue rates and i r r i g a t i o n charges collected, and K u r n o o l representing the Rayalaseema area w i t h l o w details of the w a t e r - d i s t r i b u t i o n system. These data r a i n f a l l , red soils, and relatively l o w t a n k density. T h i s together w i t h farmer benefits were used in calculating area f o r m e r l y belonged to the Vijayanagara K i n g d o m , benefits of tank i r r i g a t i o n . F o r the A k o l a tanks we could and later to the N i z a m s , but was ceded to become part of not get all the data required, since neither the p a t w a r i n o r the British-ruled M a d r a s Presidency. In M a h a r a s h t r a the officials at the district P W D had kept the necessary state the districts of A k o l a and S h o l a p u r were chosen, records. Therefore, the A k o l a data were analyzed and b o t h w i t h l o w t a n k - i r r i g a t i o n intensity, w i t h m e d i u m and interpreted separately. A l l the tanks selected in this l o w r a i n f a l l , and deep and medium-deep black soils. region are P W D surface-storage tanks of above 40 ha A k o l a belonged to Berar, a British t e r r i t o r y after 1853, command area under gravity-flow irrigation. while S h o l a p u r became a British collectorate in 1838. T h e selection of villages w i t h i n the districts was purposive; Technical Features Determining Costs t w o tanks per t a l u k were selected on the basis of availability of data f r o m i r r i g a t i o n and revenue departments at the and Performance of Irrigation Tanks taluk headquarter; tanks supplied water for at least one season in the year under study. A p p e n d i x I gives the list T h e analysis presented in the previous chapter on the of villages in w h i c h tanks were selected. In each tank area regional d i s t r i b u t i o n of tank density in I n d i a documents eight farmers were surveyed. the importance of environmental characteristics and p o p u l a t i o n density in d e t e r m i n i n g t a n k - i r r i g a t i o n intensity in different regions o v e r t i m e . Consequently, i n d i v i d - Farmer Selection ual i r r i g a t i o n tanks also differ in their economic performance because local environmental conditions A list of beneficiaries ( w i t h their respective holdings) favor one site over another. These factors influence the under the c o m m a n d area of the selected tank was technical design of an i r r i g a t i o n t a n k . obtained f r o m the p a t w a r i (village record keeper). In An understanding of some of the technical aspects of some cases where the c o m m a n d area had not been regu- tank c o n s t r u c t i o n is required to appreciate the a p p r o a c h larly cultivated, a list of cultivators w h o got water d u r i n g we have taken in the economic analysis; gaps in the data 1975-76 was prepared. O u r study aimed at c o m p a r i n g the base on some aspects made it necessary to a p p r o x i m a t e returns f r o m irrigated versus nonirrigated land cultivated some of the required i n f o r m a t i o n . Table 4 gives a sum- by the same farmer, so that the sample was d r a w n f r o m m a r y of various data sets available on i n d i v i d u a l tanks

12 Table 4. Information available from selected data sets on irrigation tanks.

Data sets

Information 1 2 3 4

28 16 Medak, A P Cuddapah, AP Mahbubnagar, AP Anantapur, AP Anantapur, AP Kurnool, AP Number of tanks Kurnool, A P 4 Medak, AP Location 45 Sholapur, Akola, Mahbubnagar, (District, State) Anantapur, AP Maharashtra Maharashtra AP

Variables Submerged area * 1 _2 - - Storage capacity * - - - Bund length * * * * Settled command area * * * * Rainfall and command-area utilization - * - - Costs - - - * Benefits - * * - Size distribution - * * - Cropping patterns - * * - Data source P W D 3 , ID C 4 ICR1SAT survey I C R I S A T survey PWD

1. * indicates information available. 2. - indicates information not available. 3. Public Works Department. 4. Irrigation Development Corporation.

and the type of analysis for w h i c h they were used. Since area". During construction, engineers determine the i n f o r m a t i o n on the costs of tank c o n s t r u c t i o n together c o m m a n d area on the basis of expected r u n o f f f r o m the w i t h i n f o r m a t i o n on bund length and settled c o m m a n d catchment area and storage capacity of the tank. T h i s area was available only f o r 16 tanks ( c o l u m n 4), we used settled c o m m a n d area is generally recorded in official this i n f o r m a t i o n to estimate the costs f o r the other tanks statistics to classify tanks according to size. f o r w h i c h only b u n d length and settled c o m m a n d area were k n o w n . Submerged Area

Bund Length A n o t h e r economically i m p o r t a n t measure related to tank size is the submerged area, that is the area covered w i t h T h e bund of a tank varies in size and shape according to water when the tank is f u l l . T h e submerged land is a t o p o g r a p h y , and constitutes a m a j o r c o m p o n e n t of the d e t e r m i n i n g factor in the costs of tank c o n s t r u c t i o n . costs of an i r r i g a t i o n tank. Therefore bunds have been designed f o r particular locations so as to o p t i m i z e water- storage capacity and m i n i m i z e the e a r t h w o r k require- Technical Relationships ment. Bunds f o u n d i n u n d u l a t i n g terrain — b e t w e e n t w o hills, f o r i n s t a n c e — a r e generally m u c h higher a n d less Table 5 presents i n f o r m a t i o n on technical relationships wide t h a n those f o u n d in fairly flat areas. of 45 tanks f r o m A n a n t a p u r district as averages f o r d i f - ferent size groups. It shows that the r a t i o of settled c o m - Tank Size m a n d area per unit of submerged area increases w i t h increase in tank size. This means that larger tanks w i t h T h e a m o u n t of water stored a n d the i n f l o w d u r i n g the taller bunds generally store m o r e water per u n i t of sub- rainy season are the m a j o r determinants of the area that a merged area. F o r small tanks ( b e l o w 40 ha settled c o m - tank can irrigate. T h e size of a t a n k is generally expressed m a n d area) this ratio is 0.9, while f o r large tanks (above by its irrigated area, the so-called "settled c o m m a n d 400 ha c o m m a n d area) it is 1.5. T h e average ratio of

13 Table 5. Technical relationships for 45 tanks of different sizes in Anantapur district.

Tank size No. of Settled command Submerged area Storage capacity Length of bund SCA/ LB/ STC/ (ha) tanks area (SCA, ha) ( S M A , ha) (STC, million m3) ( L B , m) SMA SCA SCA

Above 400 9 795 625 11.70 3453 1.46 5.1 0.014 Between 200-400 8 287 318 4.08 2883 1.29 6.9 0.014 Between 80-200 13 129 128 1.57 1190 1.29 9.6 0.013 Between 40-80 9 61 80 0.92 790 0.95 13.3 0.015 Below 40 6 29 34 0.35 582 0.90 21.9 0.012 All tanks 45 263 239 3.75 1605 1.20 10.6 0.014

settled c o m m a n d area to submerged area f o r all tanks depends on the water availability at different periods of studied is 1.2. T h e b u n d length per hectare of settled time. T h e factors affecting c o m m a n d - a r e a u t i l i z a t i o n are c o m m a n d area is 5.1 m in large tanks and increases to rainfall, local conditions, and tank-specific informat i o n . 21.9 m in small tanks w i t h an average of 10.6 m f o r all This relationship was established using 10 years' data on tanks observed. T h e average storage capacity of a tank rainfall and tank-irrigated area f o r the 28 surveyed tanks. per unit of c o m m a n d area, w h i c h is m o r e or less constant T h e u t i l i z a t i o n ratio of area actually irrigated over settled across averages of different sizes, a m o u n t s to 1.4 m of c o m m a n d area was expressed as a f u n c t i o n of annual water. rainfall, rainfall squared, and tank dummies to reflect local conditions ( v o n O p p e n and Subba R a o 1980, Part I I ) . T h e results show that in M e d a k , M a h b u b n a g a r , as Command-Area Utilization well as in S h o l a p u r districts rainfall significantly determines command-area utilization ( F i g u r e 5). T h e higher T h e settled c o m m a n d area, conceived as the o p t i m u m the r a i n f a l l , the higher is the u t i l i z a t i o n of the c o m m a n d area a p a r t i c u l a r tank w o u l d irrigate, is almost always area actually irrigated. However, command-area utiliza- underutilized. T h e area actually irrigated by a tank t i o n increases w i t h increasing rainfall at a decreasing rate.

130 Mean utilization

120

110 Medak and 100 Mahbubnagar Anantapur and 90 Kurnool 80 All regions combined 70

30 Sholapur

0 100 200 300 400 500 600 700 800 900 1000 1100 Rainfall ( m m )

Figure 5. Utilization of settled command area and annual rainfall for selected districts.

14 Benefits, Costs, and Benefit-Cost • C o m p u t e gross returns f r o m a ll tank-irrigated plots by Comparisons of Existing Tank a d d i n g m a i n p r o d u c t value plus b y - p r o d u c t value at village prices. Irrigation • C o m p u t e variable costs of c u l t i v a t i o n per p l o t including costs of h u m a n and bullock labor, seed, chemical T h e benefits a n d costs of tank i r r i g a t i o n can be measured fertilizers and f a r m y a r d m a n u r e , insecticides and pes- at three levels: (1) at the farmer's level, (2) at the level of ticides, contract charges, and i r r i g a t i o n fees. the " P r o j e c t A u t h o r i t y " responsible f o r tank construc- • C o m p u t e net returns f o r plots by subtracting total t i o n and o p e r a t i o n , and (3) at the state and n a t i o n a l variable costs f r o m gross returns f o r all plots. levels. • T h e sum of all returns on all irrigated plots, divided by Table 6 indicates the factors c o n s t i t u t i n g the costs and the sum of a l l irrigated p l o t sizes, gives the weighted benefits at each of these levels a n d the source of this data. average net returns f r o m tank i r r i g a t i o n per tank per ha. • F o l l o w i n g the same steps f o r all rainfed plots, the Benefits of Tank Irrigation weighted average net returns from nonirrigated land are c o m p u t e d . Benefits to Farmers • Farmers' net benefits due to t a n k i r r i g a t i o n are calculated as the difference between weighted net returns Financial benefits. In c o m p u t i n g the financial benefits f r o m tank-irrigated crops a n d weighted net returns to farmers, the net benefits o w i n g to i r r i g a t i o n were f r o m nonirrigated crops. derived by c o m p u t i n g differences between net returns • T h e same procedure can be repeated f o r a c o m p a r i s o n f r o m tank-irrigated crops a n d weighted average net of the economics of tanks across regions w i t h i n a returns f r o m all rainfed crops. T h i s m e t h o d minimizes c o u n t r y , but average prices a n d costs should be used the "differences-in-farmer" effect, as the same farmers instead of village prices and costs. provided data on irrigated as well as rainfed l a n d . T h e results of these calculations are presented in T a b l e T h e procedure involves the f o l l o w i n g steps: 7, columns 12 and 13. It is seen that at village prices, tank i r r i g a t i o n produced average net benefits of Rs 818 ha- 1 • Collect i n p u t - o u t p u t data on all t a n k - i r r i g a t e d and f o r 10 tanks studied in M e d a k district, Rs 946 h a- 1 f o r 10 rainfed crops. tanks studied in M a h b u b n a g a r district, and Rs 650 ha- 1

Table 6. Comparisons of costs and benefits of irrigation tanks accruing to different participants.

Comparison Participants Benefits Costs criteria

Farmer Private net returns at village Irrigation charges1 Financial prices due to irrigation1 Obligation to contribute labor3 cost-benefit Increase in land value1 Uncertainty of water ratio Reduction in risk2 availability2

Project Irrigation fees1 Land acquisition1 Financial authority Income from fisheries, Construction1 cost-benefit brick making3 Maintenance1 ratio Water fee collection3

Nation Additional production at Opportunity cost of capital Economic average prices1 invested (Interest)2 internal rate of return Additional employment1 Submerged land2 Safety in food production2 Higher water table (Increased salinity)3 Increased groundwater3 Less soil erosion3

1. Indicates survey data available. 2. Indicates information from other sources available. 3. Indicates data or information not available.

15 16 f o r 5 tanks studied in A n a n t a p u r and K u r n o o l districts. R e d u c t i o n in yield risk. T a n k i r r i g a t i o n generally redu- F o r 3 out of 4 tanks in A k o l a district, there were no ces yield risk in c o m p a r i s o n to rainfed c r o p p i n g , b u t benefits due to t a n k i r r i g a t i o n , w h i l e in S h o l a p u r district often brings w i t h it an uncertainty a b o u t the area i r r i - -1 the 3 tanks studied averaged a benefit of Rs 710 ha . gated. T h e irrigated area is adjusted to the water availa- T h u s at village prices, tanks in Telengana are highly ble, and thus the advantage of yield stability is achieved at beneficial to farmers, m o r e so t h a n in A n a n t a p u r a n d the disadvantage of area instability. T h e farmers benefit K u r n o o l . f r o m a lower v a r i a b i l i t y of yields in t a n k - i r r i g a t e d p a d d y T h e S h o l a p u r tanks t o o produced higher benefits at since their inputs are m o r e likely to r e t u r n a p r o f i t . T h i s is village prices t h a n d i d the A n a n t a p u r / K u r n o o l tanks. w h y t a n k - i r r i g a t e d paddy receives higher inputs t h a n T h e picture changes somewhat if average prices instead rainfed crops. of village prices are used to c o m p u t e farmers' benefits. In Table 8 shows the average levels of area, p r o d u c t i o n , that case the average tanks in Telengana and R a y a l a - and yields a n d their v a r i a b i l i t y f o r t w o rainfed crops 1 seema produce benefits of a p p r o x i m a t e l y Rs 1100 h a , in s o r g h u m and pigeonpea - and the m a j o r t a n k - i r r i g a t e d S h o l a p u r o n l y Rs 625 ha ', and negligible in A k o l a . c r o p , p a d d y , in three districts where tanks are the m a j o r source of i r r i g a t i o n . It is seen that the coefficient of yield Increase in land value. T h e increase in land value due to variations f o r rainfed s o r g h u m , and especially f o r i r r i g a t i o n was measured by averaging the reported values pigeonpea, are far higher t h a n f o r p a d d y . F o r v a r i a b i l i t y f o r irrigated and n o n i r r i g a t e d l a n d . Such data c o u l d be of area the opposite is true, i.e., rainfed areas are m o r e collected only in Medak, Mahbubnagar, and Anantapur stable than t a n k - i r r i g a t e d areas. An e x c e p t i o n is the case districts. These figures are also presented in Table 7. They of p a d d y yields in M e d a k district, w h i c h show an unusu- show that on an average, irrigated land is valued 2.5 times ally high coefficient of variation. While seeking to (in M a h b u b n a g a r ) to 3.4 times ( i n M e d a k district) over e x p l a i n this p h e n o m e n o n it was f o u n d that in 1972-73 d r y l a n d . In 3 tanks, 2 in M e d a k district and I in A n a n - very l o w paddy yields ( a b o u t 300 kg ha-1) were reported tapur, the value of irrigated land was reported to be m o r e f o r this district while in all other districts the yield d i d not t h a n 4 times that of n o n i r r i g a t e d l a n d . T h e lowest ratio of deviate m u c h in any year f r o m an average of a b o u t 1000 irrigated land value over n o n i r r i g a t e d was 2 . 1 , reported k g ha-1. f o r one M a h b u b n a g a r tank. Jn this p a r t i c u l a r year, the l o w yields must have been We tried to c o m p a r e the ratios of irrigated over n o n i r - caused by unusually l o w rainfall. T h e tanks were filled rigated land value w i t h net benefits. A c o r r e l a t i o n analy- and p l a n t i n g was done at the beginning of the season over sis d i d not show a n y relationship, possibly because areas that later could not be irrigated when the t a n k s , benefits measured by us reflect o n l y one year's observa- lacking replenishment f r o m rains, ran d r y . A s a result tions while land values take into account the l o n g - t e r m most of the paddy c r o p was damaged. In this p a r t i c u l a r p r o d u c t i v i t y and yield risks of the land. year in M e d a k district, the uncertainty of r a i n f a l l had n o t

Table 8. Variability in area, production, and yields in selected districts of Andhra Pradesh.

Area Production Yiield ('000 ha) ('000 000 kg) (kg ha-')

District Crop Mean CV (%) Mean CV (%) Mean CV (%)

Medak Sorghum 152.3 15.4 79.6 19.9 532 22.0 Pigeonpea 9.0 19.3 2.7 26.4 309 34.1 Paddy 88.1 24.9 111.4 45.7 1195 31.7

Mahbubnagar Sorghum 333.5 10.1 134.9 25.2 407 26.4 Pigeonpea 21.9 17.2 6.0 37.1 296 52.5 Paddy 102.4 17.6 121.7 24.2 1183 13.2

Warangal Sorghum 186.4 6.9 95.6 23.3 514 23.6 Pigeonpea 8.9 15.9 2.9 29.1 331 25.5 Paddy 114.0 27.9 147.3 33.4 1286 13.6

Combined Sorghum 672.2 8.2 310.0 17.9 462 17.8 Pigeonpea 39.8 13.6 11.6 29.9 309 38.4 Paddy 304.6 22.2 380.4 30.8 1223 14.5

Source: Estimates of area and production of ]principal crops in India, 1965-66 to 1974-75.

17 Table 9. Costs and benefits of tank irrigation to the project authority.

Cost

Present value Benefit Total Total ha-1 Total cost ha-1 Settled cost All cost assuming 22- including Benefit- Command of other of Cost ha-1 year life Rs 25 ha-1 Revenue cost Tank code1 Area bund costs project of SCA period at for maintenance collected ratio and district (SCA, ha) ('000 Rs) (Rs) 10% interest and repairs (Rs ha-1) (9)/(8)

(J) (2) (3) (4) (5) (6) (7) (8) (9) 0 0 ) Medak AA 147 1244 575 1829 12385 1521 1546 40.8 0.026 AB 291 1244 801 2044 7025 863 888 30.9 0.035 BA 188 1128 640 1768 9395 1154 1179 35.8 0.030 BB 65 453 286 739 11345 1394 1418 34.8 0.025

CA 202 813 667 1480 7329 899 924 39.5 0.043 CB 104 623 421 1044 10040 1233 1258 34.6 0.028 DA 124 660 483 1143 9195 1129 1154 32.9 0.028 DB 98 762 401 1164 11881 1460 1485 39.0 0.026

EA 90 540 376 916 10149 1245 1270 35.6 0.028 EB 66 866 289 1155 17502 2150 2175 32.1 0.015 Average 138 833 494 1327 10625 1305 1329 35.6 0.027

Mahbubnagar FA 41 254 190 444 10759 1322 1347 36.8 0.027 GA 117 792 462 1254 10682 1312 1337 36.3 0.027 GB 161 724 580 1309 8095 993 1018 40.3 0.039 HA 298 1298 806 2104 7065 867 892 30.1 0.034

HB 43 266 199 465 10744 1319 1344 32.1 0.024 JA 42 256 192 448 10754 1322 1347 34.3 0.025 KA 57 694 253 947 16717 2053 2078 28.4 0.014 KB 65 585 286 871 13366 1641 1666 35.8 0.022

LA 57 456 254 711 12454 1530 1554 29.2 0.019 LB 59 458 264 722 12140 1490 1515 26.9 0.018 Average 94 579 348 927 11278 1384 1409 33.1 0.024

Anantapur MA 450 2258 889 3147 6993 860 885 41.5 0.047 NA 375 2904 866 3770 10050 1236 1260 39.5 0.031 NB 179 983 620 1603 8962 1102 1127 40.8 0.036 Average 355 2049 792 2840 8668 1065 1090 40.5 0.037 Kurnool PA 129 790 491 1286 9961 1223 1248 33.4 0.027 QA 432 1792 887 2679 6205 761 786 33.4 0.042 Average 280 1291 692 1983 8083 992 1017 33.4 0.033

Akola RA 405 1237 882 2119 5231 643 667 52.6 0.079 RB 445 1325 888 2213 4972 610 635 62.3 0.098 SA 307 1275 818 2092 6813 838 862 60.5 0.070 TA 172 713 605 1318 7665 942 966 52.6 0.054 Average 332 1138 798 1936 6170 759 783 57.1 0.071 Sholapur UA 240 1004 733 1737 7238 890 914 84.3 0.092 VA 196 823 655 1478 7544 927 951 33.4 0.035 VB 720 2263 820 3084 4282 526 551 46.5 0.084 Average 385 1363 736 2099 6356 781 806 54.6 0.068 1. For details see Appendix Table 1.

18 o n l y affected the variability in area irrigated (as is usually employed o n tank-irrigated land i n c o m p a r i s o n w i t h the case) but it also drastically reduced yields. nonirrigated land. N o r m a l l y , however, as seen f o r the other districts i n d i - vidually and f o r the three districts c o m b i n e d , tank irriga- Security in food production. I r r i g a t i o n is generally t i o n reduces yield risks while it involves a high degree of associated w i t h security in f o o d p r o d u c t i o n . N o t all tanks area variability. have been equally reliable over the past 10 years. In fact, T h e net effect is often a higher v a ri a b i l i t y of t a n k - there appears f o r some regions a general increase in the irrigated rice p r o d u c t i o n than that of rainfed crops. H o w - instability of tank-irrigated food production, as dis- ever, this varies f r o m region to region and also f r o m year cussed in the next chapter. to year, w i t h an apparent trend towards increasing instability of tank i r r i g a t i o n , as shown in the next chapter. Environmental effects. In a d d i t i o n to the economic aspects discussed above, there would be beneficial envir- o n m e n t a l effects such as increase in g r o u n d w a t e r levels, Benefits to Project Authority and soil retention and a c c u m u l a t i o n in the t a n k beds, thus m a k i n g it possible to reclaim the eroded t o p soils. In I n d i a , at present, tank construction is planned and Unfortunately, the complexities of these more technically executed by the P W D , and tanks are operated by the relevant variables could not be considered in this study Panchayat. I r r i g a t i o n charges are collected by the for lack of measurements and data. Revenue D e p a r t m e n t . There is no T a n k I r r i g a t i o n A u t h o r i t y as yet. If there were such an A u t h o r i t y it w o u l d have to operate on the basis of i r r i g a t i o n fees as major- Tank Irrigation Costs income, but it m i g h t be able to generate some a d d i t i o n a l income by renting the tank f o r fish p r o d u c t i o n or by As in the previous section on benefits, we shall s u m m a r - selling the silt f o r b r i c k m a k i n g . ize the costs of tank i r r i g a t i o n in the same sequence, i.e., T h e patwari's records provided the last 10 years' (1) costs to farmers, (2) costs to the Project A u t h o r i t y , revenue i n f o r m a t i o n f o r 28 tanks (Table 9, c o l u m n 9). and (3) costs to the State and N a t i o n (Table 6). The revenue collected per irrigated hectare in A n d h r a Pradesh was Rs 35 on average, v a r y i n g slightly f r o m tank Costs to Farmers to tank between Rs 27 and Rs 40. In M a h a r a s h t r a , the rates are scaled according to water c o n s u m p t i o n of the Irrigation charges. Farmers' water fees for tank- different crops. On an average, a rate of Rs 56 per i r r i - irrigated land are presented in Table 7 ( c o l u m n 14). In gated hectare was charged. A n d h r a Pradesh, the a m o u n t f o r the first season is a r o u n d Rs 27 to Rs 40 ha- 1 while f o r the second season, half that a m o u n t is charged, i.e., on double-cropped land Benefits to the State and National Economy the annual revenue charged is between Rs 42 to Rs 65 ha-1. T h e net a m o u n t charged f o r water o n l y w o u l d be the Additional food production. The major benefit from difference between revenue f o r irrigated minus n o n i r r i - tank i r r i g a t i o n — as f r o m any i r r i g a t i o n project — is the gated l a n d , i.e., about Rs 27 to Rs 40 ha- 1 f o r one season, a d d i t i o n a l p r o d u c t i o n of f o o d grain it generates. T h e and Rs 42 to Rs 65 ha"1 f o r t w o seasons. T h e water fees c o m p u t a t i o n of farmers' net benefits at average prices are in the f o r m of a tax w h i c h the farmer pays together (Table 7) reflects this benefit. In 1975, the year of the w i t h his other land revenue taxes to the same Revenue survey, a hectare under tank i r r i g a t i o n produced about Department. three times more (in terms of value) t h a n a nonirrigated In Maharashtra, a different system prevails. Here the hectare. water charges are fixed in p r o p o r t i o n to the water c o n - sumed by the irrigated crops. Additional employment. Another important social benefit f r o m tank i r r i g a t i o n is the e m p l o y m e n t it gener- Uncertainty of water availability. Even t h o u g h the ates. Table 10 gives a comparison of the n u m b e r of labor farmer has the benefit of reduced yield risks, he still faces hours per hectare f o r the various tank c o m m a n d areas. It an uncertainty about the amount of water available for shows that the tanks in Rayalaseema and Telengana tank irrigation. Prevailing water-management practices e m p l o y an a d d i t i o n a l 750 to 1050 l a b o r hours h a-1 , or are aimed at adjusting the area irrigated to the actual or about f o u r to five times more than on nonirrigated land. expected q u a n t i t y of water at a p a r t i c u l a r t i m e . Conse- Interestingly, this is not true for the tanks surveyed in quently, the area irrigated varies considerably f r o m year A k o l a and S h o l a p u r districts, where there was a negligi- to year. T h e c o m b i n e d effect is p r o b a b l y a higher variable difference between the n u m b e r of labor hours bility o f paddy p r o d u c t i o n t h a n o f rainfed crops.

19 20 O u r t a n k survey provides ten years' data on the area lected. In order to c o m p a r e costs a n d benefits, cost esti- irrigated by i n d i v i d u a l tanks. T h e coefficients of varia- mates a n d technical relationships were considered to t i o n ( C V ) c o m p u t e d f r o m these data show h o w this varia- arrive at c o n s t r u c t i o n costs of the 32 tanks f o r w h i c h f a r m b i l i t y differs across tanks, d e p e n d i n g u p o n the local surveys had been made. T h e steps t a k e n to arrive at the climate, t o p o g r a p h y , l a y o u t of the catchment and the estimated costs to the t a n k b u i l d i n g a u t h o r i t y are des- c o m m a n d areas, w a t e r m a n a g e m e n t , a n d t a n k cribed below. maintenance. C o n s t r u c t i o n cost details of 16 tanks are presented in We have attempted to understand better the i m p a c t of T a b l e 11. T h e t o t a l costs of c o n s t r u c t i o n were reported these variables w i t h the help of a s i m u l a t i o n m o d e l . T h i s separately f o r five c o m p o n e n t s — bunds, sluices, weirs, exercise shows that at given rainfall distribution (Hyd e - canals, a n d land acquisition. On an average, the b u n d r a b a d , 1901-1970) in the case of t a n k s operated w i t h o u t constitutes 5 7 % of the t o t a l cost of c o n s t r u c t i o n . water c o n t r o l — i.e., the outlet is open t h r o u g h o u t the Since all tanks are located in m o r e or less s i m i l a r year as is, in fact, frequently the case f o r tanks n o r t h of t o p o g r a p h i c e n v i r o n m e n t s , there w o u l d be little v a r i a t i o n H y d e r a b a d — the t a n k - i r r i g a t e d area does v a ry consider- in the distance of earth t r a n s p o r t a t i o n required, so that ably, w i t h a CV of 25%. the b u n d cost largely depends u p o n shape and height of the b u n d . T h e shape and height of the b u n d are a p p r o x i - mately determined by the length of b u n d per u n i t of Costs to the Project Authority settled command area. Therefore, it was hypothesized t h a t the cost per u n i t length of b u n d w o u l d be related to L a n d a c q u i s i t i o n . Table 11 gives the cost of land acqui- length of b u n d per u n i t of settled c o m m a n d area. sition f o r recently constructed tanks. On an average, land In a test of this hypothesis the f o l l o w i n g f u n c t i o n a l acquisition cost per hectare of c o m m a n d area a m o u n t s to f o r m was f o u n d t o fit: Rs 720. This varies between 1 - 2 0 % of the total cost of -1 2 c o n s t r u c t i o n , d e p e n d i n g u p o n l a n d q u a l i t y a n d Y1 = 503.6 + 2598.4 X1 , R = 0.46 ownership. (3.5) where Construction costs. Data on tank-construction costs Y, = cost per length of b u n d (Rs m-1), and f o r 16 tanks recently constructed by the P W D were col- X, = length of b u n d per settled c o m m a n d area (m ha-1).

Table 11. Breakdown of tank-construction costs ('00 000 Rs) for selected districts, 1974-75.

Settled Cost Cost Cost Cost Cost of land command of of of of acquisition Total Village District area (ha) bund sluices weirs canals and misc. cost

Lanjabunda Kurnool 176 4.61 0.20 0.53 1.47 0.44 7.25 Madanantapuram Kurnool 167 14.42 0.01 3.99 5.61 2.08 27.02 Penumadi Kurnool 206 16.80 0.30 2.66 3.26 1.28 24.30 Vengaladoddi Kurnool 212 10.20 0.26 4.07 5.05 2.72 22.30

Khambalampadu Kurnool 212 11.62 0.63 8.31 3.00 3.00 26.56 Dantharvanipenta Kurnool 455 7.01 0.58 10.71 1.77 1.08 21.15 Jalvanur Kurnool 668 20.88 0.32 2.30 6.41 0.53 30.44

Jeedipalli Anantapur 79 2.35 0.20 1.03 0.91 0.88 5.37 Pinnepalli Anantapur 67 5.06 0.13 1.41 1.36 0.79 8.75 Bagiyakinapalli Anantapur 79 4.45 0.19 2.20 1.30 1.20 9.38 Chitraseedu Anantapur 158 9.36 0.51 2.27 1.00 2.68 15.82

Nandyalampeta Cuddapah 232 13.25 0.29 7.75 3.06 0.03 24.48 Kotulabanda Cuddapah 364 24.84 0.64 2.50 1.50 0.50 29.98

Gangaveru Medak 81' 2.56 0.65 0.43 0.68 0.86 5.18 Edakulapally Medak 334 9.97 0.91 2.01 4.21 3.95 20.96

Chinnamadula Mahbubnagar 129 11.80 0.29 3.43 1.02 4.00 20.54

Source: T. Hanumantha Rao, Andhra Pradesh State Irrigation Development Corporation, and Public Works Department, Minor Irrigation Department, Hyderabad.

21 T h e relationship explains 4 6 % o f the v a r i a t i o n i n costs. area. T h e relationship was f o u n d to f i t a semi-log f u n c - T h e t-value of 3.5 indicates that it is statistically h i g h l y t i o n as f o l l o w s :

significant. T h i s relationship is p l o t t e d in F i g u r e 6. 2 Y2 = 8.714 - 0.00208 X2 , R = 0.36 Based on this result it is possible to derive the b u n d (2.8) costs f o r a l l tanks in the same region f o r w h i c h i n f o r m a - t i o n o n b u n d length a n d c o m m a n d area exists. These where

derived costs are presented in T a b l e 9. Y 2 = the r e m a i n i n g cost per settled c o m m a n d area ( l o g Rs The remaining cost components (canals, sluice, over- ha-1), a n d

f l o w weir, etc.) depend on the size of the settled c o m m a n d X 2 = settled c o m m a n d area (ha).

2800

2600

2400-

Observed 2200 Estimated

2000-

1800-

1600-

1400-

1200-

1000-

800

600-

400

200

0 0 I 2 3 4 5 6 7 8 9 10 11 12

B u n d length/settled c o m m a n d area (m ha-1)

Figure 6. Relationship between bund length per settled command area and cost of bund.

22 W i t h a n R2 (the coefficient of multiple determination) his services w i t h p a d d y p r o d u c e d . T h e w a t e r charges are of 0,36 a n d a t-value of 2.8, this relationship is statistically collected by the P a t w a r i , a l o n g w i t h the l a n d revenue. significant. Using this relationship, it is possible to derive the n o n b u n d costs of all those tanks in the same region f o r Costs to the State and Nation w h i c h i n f o r m a t i o n on settled c o m m a n d area is available ( T a b l e 9). Opportunity cost of the capital invested. For simplicity By a d d i n g the t w o cost c o m p o n e n t s , an estimate of the o p p o r t u n i t y cost of capital invested was assumed to t o t a l c o n s t r u c t i o n costs is c o m p u t e d . These estimated be 10%. costs vary between Rs 4300 and Rs 16 700 ha"1 w i t h an average of Rs 9000 ha-1. In c o m p a r i s o n the actual data on Submerged land. T h e value of l a n d submerged by an t o t a l costs v a r y m o r e (note that the above estimated i r r i g a t i o n t a n k varies. Generally tanks are located so as to relationships explain only about 50% of the variation). m i n i m i z e their cost, i.e., low-value barren l a n d is pre- O u r estimations l o o k quite feasible w i t h i n the context o f ferred f o r water storage. One u n i t o f c o m m a n d area the actual cost data available. requires a b o u t 0.8 units of land to be submerged, a n d under conditions of growing population and rising land Maintenance costs. I n f o r m a t i o n on maintenance costs values, the cost of submerged land has increasing o p p o r - per tank was not available. H o w e v e r , f r o m P W D records t u n i t y value. M o r e o v e r , silt deposits in the t a n k bed lead on expenditures incurred on maintenance and repairs we to a c o n t i n u o u s increase in n a t u r a l f e r t i l i t y , thereby f i n d the f o l l o w i n g : in selected districts on an average, increasing the value of this l a n d . over the years 1973-77 total e x p e n d i t u r e on repairs varied between Rs 18 a n d Rs 27 ha- 1 (Table 12). While expendi- Level of water table. L o w e r i n g the water table by w e l l tures on o r d i n a r y repairs were between Rs 12 a n d Rs 17 i r r i g a t i o n can lead to g r o u n d w a t e r d e p l e t i o n . It is desira- h a ' , f l o o d repairs ranged f r o m less t h a n R s 5 ha- 1 i n some ble to m a i n t a i n the water table at a higher level f o r districts ( M a h b u b n a g a r , M e d a k , N a l g o n d a ) to nearly Rs p u m p i n g g r o u n d w a t e r f r o m wells. F o r a detailed e x p l a - 7 to Rs 12 h a - 1 in others (Anantapur, Chittoor, Cud- n a t i o n of benefits f r o m g r o u n d w a t e r recharge, see the dapah). These are direct expenditures made on the tanks. discussion o n C o m p o s i t e Watershed M a n a g e m e n t i n T h e costs of overheads, engineering, etc., are not C h a p t e r five. included.

Costs of water control and tank management. W a t e r Benefit-cost comparisons management, as presently practiced by the village c o m - m u n i t y , does not involve any direct costs. F a r m e r s o r g a n - To c o m p a r e costs and benefits we c o m p u t e cost-benefit ize the water c o n t r o l a m o n g themselves. In some tanks ratios at the farmers' level and at the Project A u t h o r i t y there was a water c o n t r o l l e r ( n a i r u d i ) w h o was paid f o r level. At the state level two performance parameters—t h e cost-benefit ratio and the internal rate of return—are calculated.

Table 12. Average annual expenditure (Rs ha-1 command area) by the M i n o r Irrigation Department on tank repairs in selected districts of Andhra Pradesh, 1973 to 1977. Farmer Level

A l l Ordinary Flood Financial benefit-cost ratio. T h e f a r m e r s ' net benefits District repairs repairs repairs due to tank i r r i g a t i o n vary between Rs 650 to Rs 950 h a - 1 Nalgonda 18 17 1 in red-soil areas a n d between zero and 700 in black-soil Mahbubnagar 18 15 3 areas. T h e costs incurred are the water fees, of a b o u t Rs Karimnagar 15 4 -1 19 27 to Rs 40 ha . Consequently, in red soils, f a r m e r s ' Medak 18 14 4 benefits are a b o u t 15 to 25 times the water costs in a Kurnool 18 13 5 n o r m a l year. T h u s in a n o r m a l year, tank i r r i g a t i o n is a Anantapur 19 12 7 highly p r o f i t a b l e p r o p o s i t i o n f o r the farmer. Chittoor 24 13 11 Cuddapah 15 12 27 Farmers' reduced yield risks versus uncertainty of water A l l districts 20 15 5 availability. It need not be stressed that h a r d l y ever is a Source: Government of Andhra Pradesh, Public Works Department, year " n o r m a l " w i t h regard t o r a i n f a l l d i s t r i b u t i o n . W h i l e Minor Irrigation, through personal communication of T. Hanumantha the yields of t a n k - i r r i g a t e d crops ( p a d d y ) are less variable Rao. t h a n the yields of rainfed crops, this yield stability is

23 achieved by a d j u s t i n g the irrigated area to the water T h e l o w average levels of a b o u t 0.03 in a l l districts available, thus affecting area stability. In fact, the result- indicate the h i g h degree of subsidization in t a n k i r r i g a - i n g p r o d u c t i v i t y of t a n k - i r r i g a t e d areas in Telengana is t i o n . At the project a u t h o r i t y level a b o u t 9 7 % of the costs b e c o m i n g m o r e a n d m o r e variable t h a n that o f rainfed of tanks are subsidized. areas. F o r instance, d u r i n g 1977 no crops were g r o w n in some t a n k c o m m a n d areas in Telengana because r a i n f a l l was State Level * so well d i s t r i b u t e d that it d i d n o t generate a n y r u n o f f , and farmers waited in v a i n t h r o u g h o u t the season to plant F o r c o m p a r i n g benefits and costs at the State level, their paddy. At the same t i m e rainfed land had been planted as cash flows over 20 years were analyzed. It was assumed usual w i t h s o r g h u m a n d pigeonpea a n d yielded an excel- that the net benefits f r o m i r r i g a t i o n f o r 1974-75 w o u l d be lent c r o p . T h u s while the yield risk of t a n k - i r r i g a t e d land the same f o r each of the previous 21 years. I n f o r m a t i o n is less, the u n c e r t a i n t y of water a v a i l a b i l i t y — especially was available on area irrigated f o r 10 years, f r o m 1964 to f o r tailenders — makes tank i r r i g a t i o n in Telengana a 1974. A relationship estimated between area irrigated relatively r i s k y p r o p o s i t i o n . and r a i n f a l l permitted an e s t i m a t i o n of the area a n n u a l l y irrigated f o r a n o t h e r 11 years p r i o r to 1964-65, so that a Betterment levy and increase in land value. W i t h the t o t a l of 21 years' data on area irrigated was generated. establishment o f a n i r r i g a t i o n scheme, those w h o o w n T h e flow of a n n u a l net benefits was obtained by m u l t i p l y - land w i t h i n the prospective c o m m a n d area are charged a ing the area (ha) by the net benefits per hectare. so-called " b e t t e r m e n t levy", a one-time t a x collected on T h e cost flow f o r each tank consists of the t o t a l c o n - the presumed increase in land value. T h i s levy generally s t r u c t i o n cost (in the first year) a n d the a n n u a l mainte- ranges between Rs 125 a n d Rs 300 ha-1. H o w e v e r , f o r the nance costs ( i n the f o l l o w i n g 21 years). The ratio of the surveyed tanks no records had been kept on the better- s u m m a t i o n s of the discounted a n n u a l values of benefits ment levy charged at the time of c o n s t r u c t i o n . (B) a n d costs (C) is c o m p u t e d a c c o r d i n g to the f o l l o w i n g If a levy of Rs 250 ha- 1 is assumed, then the increase in f o r m u l a ( G i t t i n g e r 1972): land value (see Table 7) is 26 to 38 times the levy in the t M e d a k a n d M a h b u b n a g a r tanks, w h i l e in A n a n t a p u r it is B t /(1+i) even 40 to 50 times higher. B C R =

t C t /(1+i)

Project Authority Level where t = 1 22 years and T h e benefits accruing to the Project A u t h o r i t y are the i - 10% rate of interest. a n n u a l revenue a n d the one - t i m e betterment levy. T h i s B C R is the benefit-cost ratio. betterment levy can be accounted against the cost of c o n s t r u c t i o n before d i s c o u n t i n g it to its present value: T a n k s w i t h a B C R of 1 or m o r e are supposed to be assuming a 22-year life period (t) a n d a 10% interest rate e c o n o m i c a l l y viable. As Table 10, c o l o u m n 4, shows, (i) on capital invested, the present value ( P ) of the cost per there are o n l y 8 tanks out of 28 f o r w h i c h this is the case. hectare of t a n k - i r r i g a t e d land ( C ) can be c o m p u t e d as A n o t h e r measure of c o m p a r i n g benefits and costs is to f o l l o w s : c o m p u t e the internal rate of r e t u r n — that interest rate at w h i c h the B C R w o u l d be ju s t one. T h i s a p p r o a c h does, of C course, present the same fact, i.e., eight tanks would have P = (1 + i)t i n t e r n a l rates of r e t u r n greater t h a n 10%. If a l o w e r rate of r e t u r n , say 5%, was acceptable to the decision makers as A life-period of 22 years is chosen because longer the c r i t e r i o n f o r economic v i a b i l i t y , then a t o t a l of 15 out periods w o u l d decrease P o n l y m a r g i n a l l y . An interest of 28 tanks w o u l d qualify. T h i s analysis shows that fewer rate of 1 0 % is chosen as it represents the average rate at t h a n h a l f of the existing i r r i g a t i o n tanks are e c o n o m i c a l l y w h i c h capital m i g h t be invested elsewhere. viable. If an a m o u n t P was deposited in the b a n k at interest Sensitivity analysis has s h o w n that the area actually rate i it w o u l d g r o w to the value of C after t years (see irrigated plays a m a j o r role in d e t e r m i n i n g the economic T a b l e 9, c o l u m n 7). To this a n n u a l cost we a d d the performance of irrigation tanks. If a higher utilizatio n of maintenance cost of Rs 25 h a -1. T h e r a t i o of i r r i g a t i o n the c o m m a n d area—at the rate of a b o u t 1 5 0 % — c o u l d be fees over present value of t a n k costs plus maintenance achieved in most years, every t a n k w o u l d be h i g h l y p r o f i t - cost per hectare is the benefit-cost r a t i o w h i c h the project able in terms of benefit-costs as well as internal rates of a u t h o r i t y faces ( T a b l e 9, c o l u m n 10). r e t u r n . Detailed suggestions to achieve a better utiliza-

24 t i o n o f the i r r i g a t i o n facility w i l l b e p u t f o r w a r d i n chap- generally generate higher p r o f i t s in A l f i s o l areas t h a n ter five of this study. in V e r t i s o l areas. I t m i g h t b e argued t h a t the l o w e c o n o m i c returns f r o m • L a n d values under t a n k i r r i g a t i o n are a b o u t 2.5 to 4 t a n k i r r i g a t i o n are offset by social benefits such as times those of drylands i n the A l f i s o l districts o f e m p l o y m e n t a n d f o o d p r o d u c t i o n w h i c h j u s t i f y t a n k i r r i - A n d h r a Pradesh. There is n o t m u c h difference in g a t i o n even where it m a y n o t be e c o n o m i c a l l y viable. In values of d r y and t a n k - i r r i g a t e d l a n d in the V e r t i s o l a d d i t i o n , it should also be considered t h a t the p o o r per- districts of Maharashtra state. f o r m a n c e of most tanks can be a v o i d e d . It is possible to • T a n k i r r i g a t i o n reduces yield risks b u t involves a increase the u t i l i z a t i o n rates in most tanks t h r o u g h better higher level of area variability. t a n k management a n d c o n t r o l . This e f f o r t w o u l d a t the • F o r the project a u t h o r i t y , the benefits are in terms of same t i m e a u g m e n t the social benefits a n d to some extent i r r i g a t i o n fees collected, w h i c h are Rs 35 h a- 1 on an increase the stability of a g r i c u l t u r a l p r o d u c t i o n under average in the A n d h r a Pradesh districts. t a n k i r r i g a t i o n . • At the project a u t h o r i t y level, a b o u t 9 7 % of the costs of t a n k i r r i g a t i o n are being subsidized. • T h e direct benefits of tank i r r i g a t i o n f o r the n a t i o n are Summary a d d i t i o n a l f o o d p r o d u c t i o n a n d e m p l o y m e n t . T h e r e are also e n v i r o n m e n t a l benefits such as rise in g r o u n d - • T h e r a t i o of settled c o m m a n d area per u n i t of sub- water table. T h e tanks in Rayalaseema a n d Telengana merged area increases w i t h increase in t a n k size. On an regions e m p l o y an a d d i t i o n a l 750 to 1050 l a b o r hours average the ratio is 0.9 f o r small tanks of up to 40 ha ha-1, w h i c h is about 4 to 5 times the l a b o r used on c o m m a n d area and 1.5 f o r tanks of above 400 ha n o n i r r i g a t e d l a n d . T h e tanks surveyed i n A k o l a a n d c o m m a n d area. S h o l a p u r districts have o n l y a m a r g i n a l e m p l o y m e n t • In M e d a k , M a h b u b n a g a r and S h o l a p u r districts r a i n - effect. fall significantly determines the percentage u t i l i z a t i o n • T h e cost of the b u n d constitutes a r o u n d 6 0 % of the of c o m m a n d area actually i r r i g a t e d ; as r a i n f a l l total cost of construction and there are economies of increases the u t i l i z a t i o n increases at a decreasing rate. scale in c o n s t r u c t i o n . • Farmers' net benefits f r o m t a n k i r r i g a t i o n at village • The area actually irrigated plays a vital role in determin- prices in the districts studied are Rs 880 h a - 1 in Tele- ing the economic performance of irrigation tanks. O n l y ngana, Rs 650 ha- 1 in Rayalaseema, a n d R s 7 0 0 ha- 1 in 8 tanks out of 28 have an internal rate of return greater S h o l a p u r . In A k o l a district t a n k i r r i g a t i o n has negligi- than 10%, and 15 w i t h 5% and above. W i t h higher ble net benefits. At average prices, Telengana a n d utilization rates tank irrigation can become an e c o n o m i - Rayalaseema regions have higher net benefits. T a n k s cally and socially profitable technology.

4 . Deterioration of Tank Irrigation and Need for Remedi a l A c t i o n

T a n k I r r i g a t i o n a s a S o u r c e o f quently the area irrigated f r o m tanks has been stagnant Instability and has even decreased in m a n y regions (see T a b l e 3). The observed decrease in tank irrigation with popula- Using statewise data f r o m 1956 to 1962 on p r o p o r t i o n of t i o n increase f r o m a certain " o p t i m u m " p o i n t o f p o p u l a - irrigated area and of area irrigated by tanks and wells to t i o n density i n the f o r m e r n o n - B r i t i s h districts o f I n d i a the t o t a l irrigated area, H a n u m a n t h a R a o (1968) f o u n d seems to be related to another p h e n o m e n o n : the increas- that v a r i a b i l i t y of a g r i c u l t u r a l p r o d u c t i o n was affected i n g instability in tank-irrigated areas ( a n d therefore p r o - significantly by tank and well i r r i g a t i o n : the higher the d u c t i o n ) i n certain regions o f I n d i a . D i s t r i c t analysis o f p r o p o r t i o n of irrigated area the lower the v a r i a b i l i t y , b u t the variability of tank-irrigated areas, using a moving the larger the share of i r r i g a t i o n f r o m tanks a n d wells the coefficient o f v a r i a t i o n ( M C V ) over 8 years ( m o v i n g f r o m higher is the v a r i a b i l i t y in p r o d u c t i v i t y . At the a l l I n d i a 1958-65 up to 1968-75), shows the f o l l o w i n g : in the dis- level, t a n k i r r i g a t i o n expanded t i l l the early 1960s; subse- tricts o f Telengana, e.g., i n W a r a n g a l , the v a r i a b i l i t y o f

25 t a n k - i r r i g a t e d area had earlier been w e l l b e l o w the v a r i a - up considerably ( F i g u r e 7). T h i s o b se rv at i on is t r u e also b i l i t y of r a m f a l l w h i c h remained at a b o u t the same level for districts in Rayalaseema, e.g., in Cuddapah (Figure t h r o u g h o u t the entire p e r i o d , w h i l e v a r i a b i l i t y o f t a n k - 8), b u t n o t ( o r n o t yet) f o r districts i n T a m i l N a d u ( F i g u r e irrigated area d u r i n g the second h a l f of the period w e n t 9) ( v o n O p p e n 1978).

Indices Variability t a n k - i r r i g a t e d area tank-irrigated area 120 45 rainfall r a i n f a l l 115- 40-

110- 35-

105 30- Mean rainfall 1015mm 100 25 Mean tank-irrigated area 79900 ha 95- 20-

90- 15^

85- 10

80 5-

0 0

8-year m o v i n g average period

F i g u r e 7. Indices ( m e a n area a n d r a i n f a l l =. 100) a n d va ri a b i l i ty of r a i n f a l l a n d t a n k - i r r i g a t e d area, W a r a n g a l district, Andhra Pradesh, India.

Indices Variability 120 45 tank-irrigated area tank-irrigated area 115 rainfall 40 r a i n f a l l

110 35

105 Mean rainfall 30 647 mm 100 25 M e a n tank-irrigated area 95 24640 ha 20

90 15

85 10

80 5

0 0

8-year m o v i n g average p e r i o d

Figure 8. Indices (mean area and rainfall = 100) and variability of rainfall and tank-irrigated area, Cuddapah district, Andhra Pradesh, India.

26 120 Indices 45 Variability tank-irrigated area tank-irrigated area 115 40 rainfall r a i n f a l l 110 35

105 Mean 30 rainfall 1117 mm 100 25 Mean tank-irrigated area 95 168790 ha 20

90 15

85 10

80 5

0 0

8-year m o v i n g average period

Figure 9. Indices (mean area and rainfall - 100) and variability of rainfall and tank-irrigated area, Chingleput district, Tamil N a d u , India.

T h e increase in the v a r i a b i l i t y of t a n k - i r r i g a t e d area is • Increase i n p o p u l a t i o n densities ( v o n O p p e n a n d p r o b a b l y a f u n c t i o n of physical as well as i n s t i t u t i o n a l Subba R a o 1980, Part I). variables, w h i c h are directly and i n d i r e c t l y related to population pressure (erosion, encroachment), and also a t t r i b u t a b l e to changes in the i n s t i t u t i o n a l e n v i r o n m e n t . Remedial Action for the Improvement A f t e r the a b o l i t i o n o f the z a m i n d a r i system, t a n k m a n - of Tank Irrigation agement, organization, maintenance, repair, water co n - t r o l , etc., ceased in most cases to be u n d e r private c o n t r o l and became the responsibility of different bodies of p u b - T a n k i r r i g a t i o n in parts of I n d i a is decreasing in extent lic a d m i n i s t r a t i o n . a n d reliability a l t h o u g h it has the p o t e n t i a l to be socially and e c o n o m i c a l l y beneficial. T h e concern is to ensure that the existing capital of i r r i g a t i o n tanks is preserved, R e a s o n s f o r D e c l i n e i n T a n k I r r i g a t i o n better utilized, a n d possibly e x p a n d e d . In the light of the i n f o r m a t i o n presented, it is clear that T h e i m p o r t a n t reasons for the decline in extent and relia- the performance of tank-irrigation technology depends b i l i t y o f tank i r r i g a t i o n i n the s o u t h e r n states o f S A T not o n l y u p o n the farmers on whose land the r u n o f f to f i l l I n d i a are: the tank is being generated and on those whose land is being irrigated, but also upon the government agencies • L a c k of soil conservation and afforestation in the w h i c h are largely responsible f o r the a d m i n i s t r a t i o n of catchment areas leading to flash r u n o f f a n d increase in tanks. This includes water distribution, maintenance, tank-bed siltation. a n d collection of water fees. Generally, the smaller tanks • Inadequate maintenance of bunds, waste weirs, a n d are governed by i n d i v i d u a l farmers' decisions w h i l e larger d r a f t channels; tanks depend u p o n g o v e r n m e n t agencies o p e r a t i n g the • Decline in the effectiveness of t a n k - a n d t a n k - w a t e r system. management (Meinzen-Dick 1984); The improvement of tank-irrigation efficiency for all • Unauthorized cultivation, tank- bed cultivation, and t a n k sizes w o u l d require a m o r e balanced i n t e g r a t i o n of foreshore encroachments; farmers' involvement, and government commitment and • Secular shift in the seasonal d i s t r i b u t i o n of r a i n f a l l participation in activities such as control of water di s t r i - ( B a n d a r a 1977); bution, maintenance and repair, revenue collection, an d

27 m a n a g e m e n t of the t a n k a n d t a n k bed as w e l l as of the the t a n k runs d r y d u r i n g the c r o p p i n g season ( v o n c a t c h m e n t areas. Oppen, Subba Rao, and Engelhardt, 1983). It should be possible to i m p l e m e n t this type of a simple c o n t r o l f u n c - t i o n by a p u b l i c a u t h o r i t y at relatively l o w cost.

C o n t r o l o f W a t e r D i s t r i b u t i o n

T h e water-use efficiency ( W U E ) of a t a n k depends largely R e g u l a r M a i n t e n a n c e a n d R e p a i r u p o n water management. J u d i c i o u s water use a n d d i s t r i - b u t i o n d u r i n g the t w o g r o w i n g seasons w o u l d result i n A n y t a n k constitutes an a r t i f i c i a l obstacle to a n a t u r a l larger areas being served f r o m a p a r t i c u l a r t a n k . Even a w a t e r w a y a n d is p e r m a n e n t l y subject to destructive f o r - h i g h water c o n s u m p t i v e c r o p such as p a d d y c o v e r i n g the ces w h i c h w o u l d eventually lead to its breaching a n d entire t a n k c o m m a n d area does n o t require the same w a s h i n g a w a y , unless it is c o n t i n u o u s l y repaired a n d well a m o u n t o f water every day. Instead, the water required m a i n t a i n e d . T h u s tanks, as o l d as some of t h e m m a y be, varies w i t h the c r o p - g r o w t h stage a n d w i t h weather a n d c a n n o t be regarded as permanent a n d stable features per wind conditions. Theoretical calculations (see followin g se. chapter) s h o w t h a t t a n k c o m m a n d area can increase T h e a m o u n t o f m o n e y available t o the P W D f o r t a n k significantly when a 'tank controller' allocates water repairs has always been claimed to be insufficient f o r o p t i m a l l y by t a k i n g these variables i n t o account. proper maintenance. Considering the Revenue Depart- N a t u r a l l y , if crops t h a t require less water are g r o w n — ment's water rates (calculated as the difference between g r o u n d n u t , s o r g h u m , c o t t o n , etc. — the W U E can be l a n d revenue f r o m d r y vs wet land) are o n l y a r o u n d Rs 35 f u r t h e r increased. H o w e v e r , such a step to increase W U E ha- 1 o f c o m m a n d area, the level o f maintenance e x p e n d i - entails considerably higher costs of o r g a n i z i n g a m o r e tures p r o b a b l y can n o t be expected to increase unless the sophisticated water-allocation system; for instance, to water rate is increased. On the o t h e r h a n d , as the capital p r o v i d e supplementary i r r i g a t i o n f o r irrigated d r y crops cost of one hectare of c o m m a n d area is a b o u t Rs 5000 to the entire canal system of a t a n k w o u l d have to be laid o u t Rs 10000 (average of Rs 7500) a n d maintenance rates so as to a l l o w f l o o d i n g of the entire c o m m a n d area w i t h i n range between Rs 17 to Rs 27 ha"1 (average of R s 2 1 ha-1) a few days w h e n a d r y spell occurs. Because of the larger this a m o u n t s t o o n l y a b o u t o n e - t h i r d o f 1 % o f the capital a n d w i d e r c o m m a n d area, longer channels w o u l d be value, w h i c h , j u d g i n g f r o m all practical experience, is not required w h i c h w i l l have t o b e lined a n d p r o v i d e d w i t h likely to be e n o u g h . adjustable outlets. S t a f f w o u l d have to be p r o v i d e d d u r - D i r e c t investigations d o not indicate h o w the s i t u a t i o n i n g those days to supervise the flushing o p e r a t i o n . i n T a m i l N a d u differs f r o m that i n A n d h r a Pradesh. It is n o t likely that radical shifts a w a y f r o m p a d d y c a n H o w e v e r , f r o m other accounts ( C h a m b e r s 1977) it w o u l d be achieved easily, because of these relatively h i g h physi- seem t h a t in T a m i l N a d u the village t a n k has often been cal a n d i n s t i t u t i o n a l investments. I n s t e a d , water alloca- regarded as c o m m o n p r o p e r t y w i t h maintenance based t i o n by a t a n k c o n t r o l l e r , a n d a system of fixing water o n c o m m u n i t y a c t i o n . " K u d i M a r a m a t h (cooperative charges a c c o r d i n g to actual water use m i g h t a l l o w less repair w o r k ) is older t h a n the B r i t i s h A d m i n i s t r a t i o n . extreme a n d therefore m o r e feasible s o l u t i o n s , i.e., a W h e n the B r i t i s h began to administer M a d r a s P r o v i n c e , change in land-use patterns, where perhaps the o u t e r they f o u n d that it was c u s t o m a r y f o r village c o m m u n i t i e s fringes of a c o m m a n d area w o u l d be planted to irrigated i n m a n y districts t o c o n t r i b u t e labor t o w a r d s repairs o f d r y crops while the areas near the t a n k are cultivated to minor irrigation sources." (Baliga 1960). p a d d y . D e p e n d i n g u p o n w a t e r a v a i l a b i l i t y f r o m year t o A gradual erosion of the capital of irrigation tanks is year, farmers c o u l d be induced to shift t o w a r d s irrigated the consequence o f inadequate maintenance. T a n k c o n - d r y crops so as to achieve better water a n d land use. s t r u c t i o n t o d a y is regarded as a welfare a c t i v i t y , a n d in A cost-efficient s o l u t i o n has to be f o u n d f o r m a x i m i z - the field of m i n o r i r r i g a t i o n , p u b l i c decision makers as i n g p r o d u c t i v i t y t h r o u g h i m p r o v e d water management. w e l l as farmers a n d private entrepreneurs often pay m o r e H o w e v e r , a n o p t i m a l p o i n t , where m a r g i n a l costs o f a t t e n t i o n t o the expansion o f p u m p i r r i g a t i o n t h a n t o i m p r o v e d water management are equal to its m a r g i n a l maintenance (not to mention expansion) of irrigation benefits, is d i f f i c u l t to determine as it varies f r o m year to tanks. year. M a i n t e n a n c e o f i r r i g a t i o n tanks requires a n n u a l M o d e l calculations using 70 years' d a i l y r a i n f a l l data to inspection and regular repair w o r k . T h e a m o u n t s spent simulate a water-storage system have s h o w n t h a t f o r an f o r repair have to be kept at levels sufficiently high to average t a n k , a simple rule of keeping the sluice closed on preserve the capital value of a newly constructed t a n k , 1 rainy days w o u l d p e r m i t a 2 0 % increase in the irrigated w h i c h n o w costs a b o u t Rs 6000 to Rs 10000 h a ' of area a n d reduce by a b o u t h a l f the n u m b e r of years that c o m m a n d area.

28 R e v e n u e Collection a n d T a n k M a n a g e m e n t m u n i t y wells below the t a n k outlets lead to a g o o d internal rate of r e t u r n ( P a l a n i s a m i a n d Easter 1984). W a t e r rates levied in the tanks under study a m o u n t to Measures f o r r e h a b i l i t a t i n g i r r i g a t i o n tanks are a b o u t Rs 35 ha-1. These water charges are collected by the required. Wherever irrigation tanks are operative under Revenue D e p a r t m e n t as a t a x on people w h o o w n i r r i - g o o d management, they show h i g h levels of p r o d u c t i v i t y gated l a n d . R e p a i r w o r k b y the P W D ( i n five-year cycles) and considerable e c o n o m i c benefits. It is w o r t h w h i l e to is financed out of the water charges previously collected. maintain this capital, with relatively small investments I n the past zamindars, w h o collected u p t o 5 0 % o f the for rehabilitation (Palanisami 1981). p r o d u c t i o n under tanks, are likely to have spent a m u c h higher a m o u n t on c o n s t r u c t i o n as well as on maintenance and repairs t h a n is spent n o w by g o v e r n m e n t agencies. S u m m a r y A l s o , the p r o v i s i o n that the same person, i.e., the z a m i n - d a r or his equivalent, was responsible f o r maintenance as • Tank irrigation, formerly a source of relative stabil i t y , well as revenue collection a l l o w e d f o r m o r e direct atten- has become m o r e a n d m o r e unreliable. It is n o w a t i o n to urgently needed repairs t h a n is possible in the source o f instability f o r a g r i c u l t u r a l p r o d u c t i o n i n present system in w h i c h t w o separate G o v e r n m e n t m a n y parts o f I n d i a . departments are responsible f o r revenue c o l l e c t i o n a n d • M a j o r factors causing the d e t e r i o r a t i o n of t a n k i r r i g a - maintenance. tion include: environmental degradation such as deforestation, over grazing, soil erosion, siltation, etc., all of w h i c h are related to increases in p o p u l a t i o n density; lack of administrative structures for tank maintenance A v o i d i n g T a n k - b e d C u l t i v a t i o n a n d repair, a n d t o p r o v i d e p r o p e r water c o n t r o l a n d general tank management. T a n k beds should be kept free f r o m c u l t i v a t i o n so that • Remedial measures for improvement of existing tanks desiltation is not i n h i b i t e d ; they c o u l d be used f o r grazing include: increase in efficiency of water use by c o n t r o l or to g r o w trees in the upper fringes. T a n k - b e d c u l t i v a - of water distribution and management, regular and t i o n and the subsequent acquisition of o w n e r s h i p rights t i m e l y maintenance and repair, regular desiltation of by individuals is likely to reduce storage levels of tanks. tank beds (beneficiaries should share the responsibility), avoidance of tank-bed cultivation, creation of an agency responsible f o r revenue collection a n d t a n k management, soil conservation and afforestation mea- Desiltation o f T a n k Beds sures to c o n t r o l erosion, l i n i n g of field channels to avoid transit losses, and farmers* cooperatives at the T h o u g h c o n t r o l l e d erosion minimizes t a n k - b e d s i l t a t i o n , tank level f o r efficient water management. it does n o t entirely eliminate it, and over t i m e , the a c c u m - ulated silt w i l l reduce the effective storage capacity of the t a n k . Regular desiltation of existing tanks should be the responsibility of a public body. T h e fertile silt can be d u g up and redistributed on the uplands f r o m where it o r i g i - nated, thereby u p g r a d i n g the value of these uplands. At the same time, the storage capacity of the t a n k w o u l d be restored.

L i n i n g o f I r r i g a t i o n Channels a n d F a r m e r Cooperation

A study o f t e n tanks of v a r y i n g sizes in R a m a n a t h a p u r a m district i n T a m i l N a d u clearly indicates the i m p o r t a n c e o f farmer cooperation for efficient management of tank i r r i g a t i o n . T h e government departments should encour- age such organizations a n d help in i d e n t i f y i n g a strong local leadership. Studies have s h o w n that investments in l i n i n g i r r i g a t i o n channels and the i n s t a l l a t i o n o f c o m -

29 5. Alternatives for Improving Tank Irrigation

W a t e r m a n a g e m e n t holds one o f the m o s t i m p o r t a n t keys i r r i g a t i o n a n d the present o r g a n i z a t i o n o f t a n k manage- t o i m p r o v e d p r o d u c t i v i t y o f a g r i c u l t u r a l l a n d use i n the m e n t were studied in the states of A n d h r a Pradesh, S A T . As has been s h o w n a b o v e , t a n k i r r i g a t i o n is a Maharashtra, Karnataka, and Tamil Nadu. The w a t e r - m a n a g e m e n t t e c h n o l o g y w h i c h can p r o d u c e c o n - expected costs a n d returns of a T I A were assessed to siderable economic and social benefits. Its present decline assure a d m i n i s t r a t i v e as w e l l as e c o n o m i c feasibility i n I n d i a u n d e r the influence o f g r o w i n g p o p u l a t i o n pres- ( V e n k a t r a m 1985). sures a n d i n c o m p e t i t i o n w i t h alternative technologies (such as w e l l i r r i g a t i o n ) is a fact w h i c h calls f o r r e m e d i a l measures. S o m e measures, m a n y of w h i c h have also been Present Situation suggested by o t h e r a u t h o r s , are presented in the previous chapter. These represent " s o f t " measures f o r r e m e d i a l The organization and management of tank irrigation a c t i o n . I n f o r m a t i o n on such remedial measures is rele- differs across states. H o w e v e r , generally f o r s m a l l t a n k s vant n o t o n l y t o preserve the " c a p i t a l " o f i r r i g a t i o n t a n k s the responsibility f o r maintenance a n d repairs a n d w a t e r in I n d i a w h i c h is in danger of being fast depleted. Lessons r e g u l a t i o n rests w i t h village a u t h o r i t i e s , w h i l e f o r larger learned f r o m the I n d i a n experience w i l l also be of use to tanks the M i n o r I r r i g a t i o n D i v i s i o n o f the P u b l i c W o r k s areas where t a n k i r r i g a t i o n is b e c o m i n g feasible n o w , i.e., Department (PWD) is responsible. Revenue collection where p o p u l a t i o n densities have reached t h r e s h o l d levels f o r a l l tanks is in the hands of the Revenue D e p a r t m e n t , o f 5 0 t o 100 persons k m2 a n d where g e o g r a p h i c a l c o n d i - except in M a h a r a s h t r a ( T a b l e 13). T h i s d i v i s i o n of tions are c o n d u c i v e to the m o r e intensive land-use system responsibilities leads to a d i f f u s i o n of a c t i v i t y . Better o f t a n k i r r i g a t i o n . S u c h regions exist i n West A f r i c a linkage between decision makers a n d c o o r d i n a t i o n o f ( n o r t h e r n N i g e r i a , M o s s i Plateau i n B u r k i n a Faso, etc.) decisions regarding o p e r a t i o n a n d m a i n t e n a n c e o f irriga- a n d i n north-eastern T h a i l a n d . t i o n tanks c o u l d b r i n g a b o u t m o r e effective t a n k manage- H o w e v e r , it appears that in m a n y cases a n d u n d e r m e n t a n d water c o n t r o l . A t present i n most o f the tanks, p a r t i c u l a r c o n d i t i o n s such " s o f t " measures are not suffi- p a r t i c u l a r l y the smaller ones, the w a t e r flow is either cient to cope w i t h the s i t u a t i o n . O f t e n m o r e decisive c o n t r o l l e d very c r u d e l y or not at a l l by keeping the outlet a c t i o n is r e q u i r e d , d e m a n d i n g s o m e w h a t m o r e far- c o n t i n u o u s l y open. In such cases, once it is opened there reaching decisions t h a n merely the advice to do m o r e or is h a r d l y any i n t e r m e d i a t e a d j u s t m e n t of the f l o w accord- Jess of one or a n o t h e r type of a c t i v i t y . In those cases ing to water requirements. " s o f t " measures m a y have to be replaced by " h a r d " T h e rates charged f o r t a n k water v a r y considerably a c t i o n . f r o m state to state and w i t h i n states f r o m region to W e present b e l o w t w o alternative concepts f o r region, owing to historical developments and past pract i - i m p r o v e d w a t e r m a n a g e m e n t . ces. Generally, the rates charged f o r t a n k water are o n l y a b o u t one t h i r d to one f i f t h of w h a t they o u g h t to be if (1) T h e concept of t a n k m a n a g e m e n t t h r o u g h a T a n k they are to cover the discounted costs of t a n k construc- Irrigation Authority (TIA). This concept is still aim- t i o n a n d maintenance. H o w e v e r , drastic increases in i n g a t the preservation o f tanks t h r o u g h better m a n - water rates w o u l d be p o l i t i c a l l y d i f f i c u l t to enforce; there- agement of t a n k water, but by w a y of a definitive f o r e , instead of c h a r g i n g higher water rates, increased administrative infrastructure. p a r t i c i p a t i o n o f farmers i n t a n k m a i n t e n a n c e a n d o r g a n i - (2) T h e concept o f C o m p o s i t e W a t e r s h e d M a n a g e m e n t z a t i o n should be envisaged. ( C W M ) o n A l f i s o l s . T h i s concept i s m o r e r a d i c a l i n The state governments continue to invest in physical the sense t h a t it accepts the fact that t r a d i t i o n a l maintenance and even e x p a n s i o n o f t a n k i r r i g a t i o n . i r r i g a t i o n tanks w i l l become technically obsolete i n G o v e r n m e n t expenditures recorded d u r i n g 1951 to 1980 the w a k e o f new technologies f o r water l i f t i n g a n d for minor irrigation (gravity flow) show that in the states water management. f o r w h i c h i n f o r m a t i o n was available, Rs 3000 to Rs 3500 was spent per hectare of new area u n d e r i r r i g a t i o n , a m o u n t i n g to a b o u t 1 m i l l i o n hectares in the three states The Concept of a Tank Irrigation o f A n d h r a Pradesh, K a r n a t a k a , a n d T a m i l N a d u ( T a b l e A u t h o r i t y 14). H o w e v e r , such physical investments are n o t likely to p r o d u c e returns if they are not supplemented w i t h T h e concept o f a T a n k I r r i g a t i o n A u t h o r i t y ( T I A ) was appropriate organizational structures for efficient opera- e x p l o r e d a t the state level. T h e e x i s t i n g c o n d i t i o n s o f t a n k t i o n of t a n k - i r r i g a t i o n systems. A l s o , a c o m p a r i s o n of

30 Table 13. Responsibilities for irrigation-tank management in four Indian states.

State Tank command area Public Works Department Revenue Department Village

Andhra < 40 ha in Telengana na1 Revenue collection Maintenance and repair Pradesh < 80 ha in Andhra Water regulation 40-400 ha in Telengana 80-400 ha in Andhra Maintenance and repair Revenue collection na Water regulation > 400 ha Maintenance and repair Revenue collection na Water regulation

Karnataka < 4 ha na Revenue collection Maintenance and repair Water regulation 4-80 ha Maintenance and repair Revenue collection Water regulation under Supervision of water supervision regulation > 80 ha Maintenance and repair Revenue collection na Water regulation

Maharashtra < 100 ha na Revenue collection Maintenance and repair Water regulation > 100 ha Maintenance and repair na na Water regulation Revenue collection

Tamil Nadu < 40 ha na Revenue collection Maintenance and repair Water regulation > 40 ha Maintenance and repair Revenue collection na Water regulation

I. na = not applicable.

different sources of statistical i n f o r m a t i o n shows that in The Organization of a Tank Irrigation most states accurate and consistent data on m i n o r irriga- A u t h o r i t y t i o n are not always available; f o r e.g., the Revenue De- partments report tank-irrigated areas to be considerably lower than w h a t the Public W o r k s D e p a r t m e n t s show. In order to achieve better tank management w i t h m o r e intensive farmers' participation, a Tank Irrigation A u t h o r i t y ( T I A ) i s proposed. Essentially the T I A w o u l d integrate the village-level tank-irrigation committees Table 14. Total government expenditure on minor irrigation, 1951 to 1980. along w i t h the water regulators a n d / o r supervisory staff i n t o the existing hierarchy of the m i n o r i r r i g a t i o n a d m i n - Expenditure New area Total istration (Table 15). The administrative structure that per unit area under irriga- expenditure evolves by establishing close links between the existing State (Rs tor') tion (X)00 ha) ('000 000 Rs) organization and the new village-level irrigation commi t - Andhra Pradesh 3382 346 1170 tee may b r i n g a b o u t a greater degree of agreement a m o n g Karnataka 3331 437 1455 farmers, b o t h on water-management practices a n d their Tamil Nadu 3049 218 665 enforcement. Farmers w o u l d m o r e easily accept a village-

Table 15. Organizational pattern of the Tank Irrigation Authority ( T I A ) at different administrative levels.

1. Tank level Tank Irrigation Committee or Village Irrigation Committee employing Tank Water Regulator (TWR) 2. Taluk level Junior Engineer, Minor Irrigation, and Assistant Agricultural Officer 3. Divisional level Assistant Engineer, Minor Irrigation, and District Agricultural Officer 4. District level Executive Engineer, Minor Irrigation, and Deputy Director of Agriculture 5. Regional level Superintending Engineer, Minor Irrigation, and Joint Director of Agriculture 6. State level Chief Engineer, Minor Irrigation, and Director of Agriculture 7. Government level Secretary, Public Works Department

31 level a u t h o r i t y to assure i m p r o v e d water-management A s i m u l a t i o n m o d e l was b u i l t ( v o n O p p e n et a l . 1983) practices if it was apparent that the ensuing benefits to c o m p u t e the a m o u n t of water w h i c h c o u l d be saved if w o u l d be higher. the sluice remains closed on rainy days. Based on 70 years' d a i l y rainfall data at H y d e r a b a d , the m o d e l c o m - putes the effect of different water-control rules. It calcu- I m p r o v e m e n t o f W a t e r C o n t r o l i n Existing lates (1) the chances f o r successfully g r o w i n g a c r o p in the T a n k s rainy season (there is still water in the t a n k in the 4 3 r d week) a n d (2) the a m o u n t of water available f o r g r o w i n g a Research on i r r i g a t i o n tanks in s o u t h e r n I n d i a has s h o w n second c r o p (at the end of the 4 3 r d week). T h e 43rd week t h a t t a n k i r r i g a t i o n can be p r o f i t a b l e ( v o n O p p e n a n d is assumed to be the end of the first season f o r a rice c r o p Subba Rao 1980). In actuality, however, most irrigatio n w h i c h takes a b o u t 120 days to m a t u r e . tanks p e r f o r m p o o r l y . T h i s is reflected in the overall T h e results are presented in Table 16. T h e y show that decline of tank-irrigated area a n d the g r o w i n g instability. in a c o m m a n d area of 10 ha, a w a t e r - c o n t r o l rule of W a t e r d i s t r i b u t i o n in some tanks m a y be managed in a closing sluices on rainy days w o u l d reduce the n u m b e r of r u d i m e n t a r y m a n n e r by c o n t r o l l i n g the date on w h i c h the years d u r i n g w h i c h the tank runs d r y before harvest f r o m sluice is opened, but once this is d o n e , the water is gener- 50 years to 40 years, i.e., the p r o b a b i l i t y of c r o p failure f o r ally let out continuously. W a t e r controllers w h o were this particular tank w o u l d f a l l f r o m 0.69 to 0.56. These once in charge of operating the sluice have n o w almost probabilities of c r o p failure are relatively h i g h because of completely vanished. Better water management could be the small tank size assumed. Larger tanks have relatively achieved by very simple measures, such as: (1) c o n t r o l l i n g lower evaporation losses and therefore would benefit the o u t f l o w at night, thereby reducing e v a p o r a t i o n over- even m o r e f r o m w a t e r - c o n t r o l methods that help water n i g h t , (2) keeping the sluice closed on r a i n y days (assum- storage over longer periods. A s s u m i n g a 2 0 % increase in i n g that rainfall w i l l be sufficient to supply the the c o m m a n d area, water c o n t r o l w o u l d decrease risk of requirement on a r a i n y day), a n d (3) a c o m b i n a t i o n of c r o p failure f r o m 0.73 to 0.59. these t w o . I n s u m m a r y , water c o n t r o l o f the k i n d described w o u l d N o n e of these measures w o u l d require any physical permit i r r i g a t i o n of a 2 0 % larger c o m m a n d area at a 17% change for the t a n k as such. T h e structures of the water lower risk of c r o p failure ( f r o m 0.69 to 0.59), and the outlet w o u l d r e m a i n as they are since outlets in most water left in the tank at the end of the first season w o u l d tanks are t r a d i t i o n a l l y fitted w i t h a r o u n d hole i n t o w h i c h be 2 4 % m o r e t h a n the a m o u n t stored w i t h no water a conical w o o d e n p l u g can be pushed f r o m the t o p of the c o n t r o l . b u n d . There w o u l d be no need f o r i m p r o v e d d i s t r i b u t i o n The increased irrigated area w o u l d generate a d d i t i o n a l channels nor for new cropping systems; paddy irrigation revenue to the g o v e r n m e n t , as higher rates w o u l d be and field-to-field f l o w w o u l d continue. collected f r o m the larger areas. T h i s w o u l d be sufficient

Table 16. Results of the Simulation Model of Tank Operation with Irrigation on Alfisols (Basis: 1901 to 1970 daily rainfall data for Hyderabad).

Command Area 10 ha 12 ha

Water requirement 1000 m3 d - 1 outlet 1200 m3 d-1 outlet

Daily No outlet Daily No outlet outlet on rainy outlet on rainy Control days days

Case (1)1 (2)2 (3)1 (4)2 No. of years with empty tank at the end of the 43rd week (end October) 48 39 51 41

Probability of empty tank (%) 69 56 73 59

Average volume of water remaining in tank after 43rd week (m3) 23800 33000 22200 29600

Relative water saving (%) 100 139 100 133 100 139 93 124

1. Without water control. 2. With water control.

32 Table 17. Expected returns and expenditure (000 000 Rs) from improved water-management alternatives in tank-irrigated areas of selected Indian states.

Alternative expected expenditure

Supervision and water regulation

Grant for Government6 Expected returns water regulator Inspectors Govern- Govern- and Super- Farmers1 ment2 Farmers3 ment4 Farmers5 supervisors visors

Andhra Pradesh 140.0 6.8 24.0 6.0 30.0 6.24 4.80 Karnataka 65.6 5.2 19.2 4.8 24.0 3.12 2.40 Maharashtra 19.3 6.2 N A7 NA NA NA NA Tamil Nadu 129.7 9.4 9.9 6.6 16.5 4.78 3.67

1. From 20% additional irrigated area at average farmers' net returns. 2. From 20% additional irrigated area at present water rates. 3. Farmers pay 80% of salary (Rs 100 month-1) for water regulators. 4. Government pays 20% of salary (Rs 25 month-1) for water regulators. 5. Farmers pay full salary (Rs 125 month-1) for water regulator. 6. Government pays for special supervisory staff, either a) inspectors (one per 50 tanks) and supervisors (one per 20 inspectors), or b) supervisors (one per 100 tanks). 7. NA = data not available. Source: BR. Venkatram (1985).

to e m p l o y the tank managers required. Substantial extra these committees w o u l d e m p l o y a water regulator f o r income w i l l also accrue to those cultivators w h o w o u l d every tank. C o n d i t i o n s in the states of M a h a r a s h t r a , b r i n g a d d i t i o n a l land under i r r i g a t i o n (Table 17). Andhra Pradesh, Karnataka, and Tamil Nadu were stu- M o r e o v e r , farmers w i l l derive benefits d u r i n g those years died to propose the most feasible o r g a n i z a t i o n . T h e costs w h e n the t a n k does not r u n d r y p r e m a t u r e l y (as w o u l d of the w a t e r - c o n t r o l systems projected f o r each state were have happened w i t h o u t water c o n t r o l ) . These benefits are c o m p a r e d w i t h the expected returns f r o m a 2 0 % larger less visible but amount to another 5% of total irrigated tank-irrigated area. These comparisons are presented in area. T h a t is, if a water regulator controls the f l o w , a n d T a b l e 17. It shows f o r each of the states included in the instead of r u n n i n g d r y every 10 years w i t h o u t water study the expected t o t a l returns to farmers a n d to the c o n t r o l the t a n k runs d r y o n l y every 20 years, then instead state governments from a water-control system. The of 10% the loss is o n l y 5% w h i c h implies a gain of 5% in returns to farmers of course exceed those to the state the a n n u a l net returns f r o m the irrigated area. T h i s stabil• governments by a m u l t i p l e of over 15, as the farmers' ity gain w o u l d p r o v i d e the m a j o r a r g u m e n t to convince average net returns from tank-irrigated agriculture all farmers that they w o u l d have to c o n t r i b u t e to s u p p o r t exceed the presently paid water rates by the same such a water regulator. In a d d i t i o n , the general a r g u m e n t m u l t i p l e . holds that water rates are n o t being increased even T h e t w o alternatives envisaged f o r f i n a n c i n g the though costs have increased. Water control will, of schemes in the different states, and expenditures required course, not be free of cost. An o r g a n i z a t i o n to e m p l o y are also presented in Table 17. O n e , a state government and supervise t a n k controllers has to be set up. T h i s grant would cover 20% of the water regulator's salary, o r g a n i z a t i o n has to be planned f o r i n d i v i d u a l states in while the remainder w i l l be paid by the farmers, w h o w i l l I n d i a in such a way that it fits into the existing structure also provide supervision. T w o , the farmers w o u l d be of the d e p a r t m e n t responsible for t a n k i r r i g a t i o n . entirely responsible for the salary while the g o v e r n m e n t w i l l p r o v i d e supervisors a n d / o r inspectors. T h e e x p e n d i - ture f o r farmers w o u l d in all cases be o n l y a f r a c t i o n of Expected Costs of W a t e r R e g u l a t i o n their returns f r o m a 2 0 % a d d i t i o n a l c o m m a n d area; the expenditure f o r the government w o u l d in no case exceed T h e government and farmers, w i t h their investments their returns f r o m increased income f r o m water charges p o o l e d , should be able to achieve t h r o u g h the T I A m u c h on the 2 0 % a d d i t i o n a l irrigated area. m o r e t h a n c o u l d be effected by either p a r t y separately. This exercise is indicative of the feasibility of the T a n k - i r r i g a t i o n committees w o u l d have to be f o r m e d scheme at the aggregate level; the scheme is feasible a n d at the village level a c c o r d i n g to certain statutory rules; economically highly profitable to farmers w h i l e also

33 moderately remunerative t o governments ( V e n k a t r a m basis to the extent of a n n u a l recharge of g r o u n d w a t e r 1985). replacing the amount withdrawn. T h e i m p l e m e n t a t i o n of the scheme at the village level Research at I C R I S A T Center was initiated in 1981 to m a y i n i t i a l l y pose some p r o b l e m s , as those w h o n o w have assess the p o t e n t i a l of this concept, keeping in view the access to sufficient water m i g h t have fears a b o u t its avail- cost factors listed above a n d c o m p a r i n g these w i t h the a b i l i t y w h e n the c o m m a n d area is extended. T h e i r expe- expected advantages i n a n o p t i m i z a t i o n f r a m e w o r k ( f o r rience, however, of better stability of water supplies f o r details see Engelhardt 1984). the first season a n d having 2 4 % m o r e water f o r the T h i s research was based on field surveys a n d a discrete second season ( w h i c h has not been accounted f o r in terms stochastic linear programming model. The model allows of a d d i t i o n a l irrigated area) should convince the reluc- the user t o assess the impact o f C W M o n S A T agricul- t a n t ones to collaborate. ture, w h i c h is constrained by the stochastic nature of its T h i s concept o f establishing a T I A w o u l d fall i n t o the water supply. Parametric changes a n d sensitivity analysis category of indirect investment approaches, w h i c h of critical technical a n d economic parameters such as C o w a r d (1985) favors as a measure f o r i n d u c i n g farmers' well density, factor cost, and product prices permits iden- p a r t i c i p a t i o n a n d m o b i l i z a t i o n of local resources. tification of a promising natural and socioeconomic Nevertheless, further study and experimental research environment for implementation of the new concept. in villages is required to decide h o w best a n d where to Results f r o m the m o d e l runs have been summarized in i m p l e m e n t this concept. A p r o p o s a l f o r such e x p e r i m e n - Figure 10. T h e benefits f r o m water management were t a l research on t a n k c o n t r o l was s u b m i t t e d to and calculated in terms of net returns ( R s ha-1) a n d e m p l o y - accepted b y the G o v e r n m e n t o f A n d h r a Pradesh, C o u n - ment (man-days ha-1). For comparison, the benefits of cil f o r Scientific Research, in 1984. five different systems were calculated, r a n g i n g f r o m a s i t u a t i o n of rainfed agriculture w i t h o u t any wells to systems w i t h wells (at three levels of well densities), but w i t h little or no groundwater recharge. Composite Watershed Management R a i n f e d agriculture w i t h o u t wells produces net returns ( C W M ) o n A l f i s o l s of Rs 200 ha- 1 and provides e m p l o y m e n t of a b o u t 30 man-days ha-1. In contrast, well irrigation drastically H i s t o r i c a l l y one can observe a n o n l i n e a r relationship increases benefits to twice (at 5 wells per 100 ha) or m o r e between p o p u l a t i o n density a n d t a n k i r r i g a t i o n in large t h a n thrice (at 15 wells per 100 ha) the levels of rainfed parts of I n d i a ; tanks tend to be established at p o p u l a t i o n agriculture. However, especially at higher densities, well densities of 50 to 60 persons k n r2 a n d higher p o p u l a t i o n irrigation is restricted by limited groundwater recharge. densities b r i n g a b o u t m o r e tanks up to a m a x i m u m of Substantial increases in net returns can be generated at a b o u t 220 persons k m "2 , beyond w h i c h tanks tend to h i g h well densities t h r o u g h artificial g r o u n d w a t e r decrease ( v o n O p p e n and Subba R a o 1980, Part I). T h i s recharge. At o p t i m u m levels of g r o u n d water recharge the observation is based on the simple t r u t h that w i t h increas- increase in p r o d u c t i v i t y w o u l d be a b o u t 3 0 % at l o w well i n g p o p u l a t i o n pressure the value of the land w h i c h a tank densities of 5 wells per 100 ha but 7 0 % at densities of 15 occupies increases. Consequently, the rationale of the use wells per 100 ha. a n d maintenance of the t a n k as a c o m m o n property T h i s concept o f C W M attains a d d i t i o n a l significance i f resource is increasingly being questioned by farmers and we l o o k at it in the context of developments in water- landless people. Private claims on the fertile t a n k land are lifting technology. Groundwater-exploitation technolo- f o l l o w e d by encroachments, w h i c h in t u r n lead to lower gies such as locating g r o u n d w a t e r , d r i l l i n g deep wells, water levels a n d decreased i r r i g a t i o n efficiencies. and energized p u m p i n g have become increasingly access- At the same t i m e , wells in the t a n k c o m m a n d area do ible to farmers. Credit institutes t o o are encouraging use p r o v i d e water f o r i r r i g a t i o n . I f tapped a n d recharged o f g r o u n d w a t e r f o r i r r i g a t i o n . efficiently, this g r o u n d w a t e r reservoir can irrigate a l l or N e w technologies such as solar-powered p u m p s are m o r e of the land f o r m e r l y served by the t a n k , assuming likely to be available in the near future. A study by Sir favorable hydro-geologic characteristics. William Halcrow (1983) states that: "Solar pump costs T h e a p p r o a c h proposed here aims at i n c o r p o r a t i n g the have declined appreciably and w i l l p r o b a b l y continue to entire watershed, i.e., the traditional catchment of a tank do so. At the cost levels w h i c h it is predicted w i l l a p p l y by plus its submerged and c o m m a n d areas. F o r such an area 1987, the Specific C a p i t a l Cost of systems designed to a management system is envisaged w h i c h combines p u m p t h r o u g h static lifts of 7m a n d 2 0 m are estimated to erosion- and runoff-controlling land management (i.e., be in the band $0.9 to $ 1.5 k J-1 d -1, c o m p a r e d w i t h a r o u n d t h r o u g h vegetative cover, b u n d s , check d a m s , small per- $2.8 k J-1 d - 1 f o r w e l l designed systems at prices current in c o l a t i o n tanks, etc.) w i t h i r r i g a t i o n wells f o r l i f t i n g Phase I. As the price of p h o t o v o l t a i c arrays continues to g r o u n d w a t e r . T h e well water is being lifted on a sustained fall and systems become more efficient and manufactured

34 1 2 3 4 5 1600 160 N o Wells w i t h o u t Wells w i t h one Wells w i t h c o n - Wells w i t h wells structures for percolation tank stant area under optimal area 1400 groundwater per well percolation under perco- •140 recharge tanks lation tanks 1200 120

1000 100

800 80

600 6 0

400 4 0

200 •20

0 • 0 10 ■10 20 2 0 30 ■ 3 0

Man-days ha-1 Rs ha-1 % area N o . o f submerged wells (100 ha)-1

Figure 10. Net returns and employment on an Alfisol watershed under alternative water-management systems (results based on a model).

in greater v o l u m e , the specific capital costs should f a l l to Simulation results show that with the improvement of a r o u n d $0.5 k J-1 d - 1 by 1993." T h e specific capital cost is water c o n t r o l , e.g., by closing sluices on r a i n y days, a the capital cost of the system per u n i t of h y d r a u l i c energy 2 0 % larger c o m m a n d area can be irrigated. A c c o r d - o u t p u t over a standard solar day of 5 K W H m-2. ingly, creation of a T a n k I r r i g a t i o n A u t h o r i t y ( T I A ) is Solar p u m p s require relatively shallow water tables proposed f o r t r a i n i n g a n d supervising the water c o n - f r o m w h i c h t o lift water; C W M w i l l b e o f help t o ensure trollers and f o r being responsible f o r revenue collec- sustained i r r i g a t i o n by means of solar energy f r o m water t i o n as w e l l as repair a n d overall t a n k management. tables maintained at reasonably shallow levels. This wi l l Investment required to set up a n d operate the T I A is yield not o n l y economic benefits but also a socially desir- j u s t i f i e d by the expected returns f r o m increased a n d able effect of equitable access to water, since f a l l i n g m o r e stable p r o d u c t i o n in the t a n k c o m m a n d areas. groundwater levels call for deeper wells and larger capac- T w o concepts are being e x p l o r e d , one being conserva- ity p u m p s w h i c h o n l y the richer farmers can a f f o r d . A t i o n of tanks a n d the other, m o r e radical, a i m i n g at solar-powered groundwater-managed system of well irri- C W M . These concepts should be tested e m p i r i c a l l y in g a t i o n w o u l d provide m o r e even access to well i r r i g a t i o n field experiments. f o r all farmers. T h e concept o f C W M o n Alfisols involves a system o f r u n o f f - a n d e r o s i o n - c o n t r o l l i n g land management f o r enhanced g r o u n d w a t e r recharge a n d sustained w e l l irrigation. This concept was analyzed at ICRISAT S u m m a r y Center a n d was f o u n d to generate considerable gains in net returns a n d e m p l o y m e n t . F u r t h e r research on • T a n k - w a t e r controllers c o u l d be reintroduced at the C W M i s presently u n d e r w a y a t t w o locations, A u r e - village level to increase the water-use efficiency. palle and Anantapur, to substantiate these findings.

35 6. S u m m a r y a n d Conclusions

T a n k - i r r i g a t i o n technology has had a deep influence on w h i c h generate internal rates o f r e t u r n o f 2 3 % . H i g h the c u l t u r a l development i n m a n y regions o f I n d i a . Spa- water-use efficiency and command-area utilization are t i a l d i s t r i b u t i o n of t a n k i r r i g a t i o n has been determined the m a j o r factors associated w i t h h i g h rates of r e t u r n p r i m a r i l y by physical factors such as h a r d r o c k substra- from tank irrigation. t u m , v a p o r pressure, p o s t m o n s o o n rains, l o w moisture- Since tank i r r i g a t i o n has potentially high economic h o l d i n g capacity of soils, and by p o p u l a t i o n density. payoffs, means to rehabilitate i r r i g a t i o n tanks should be T a n k i r r i g a t i o n , especially in southern I n d i a , is very f o u n d . In order to increase water-use efficiency, t a n k - closely i n t e r w o v e n w i t h settlement p a t t e r n and village water controllers should be reintroduced at the village o r g a n i z a t i o n . Nevertheless, in m a n y parts of the c o u n t r y , level, a n d a u t h o r i z e d to operate the water sluices f o r especially in areas of h i g h p o p u l a t i o n density, i r r i g a t i o n better water c o n t r o l . F o r m a t i o n of a T a n k I r r i g a t i o n tanks are in decay a n d the area irrigated by tanks is A u t h o r i t y ( T I A ) at the state level is r e c o m m e n d e d . T h e declining. T I A w o u l d t r a i n a n d supervise the water controllers a n d There are three reasons f o r this decline in tank irriga- be responsible for improved tank management. Cost cal- t i o n . (1) T h e h u m a n pressure on l a n d transforms the culations show that the investment required to set up and environment and affects the performance of irrigation operate a T I A in the three southern states of A n d h r a tanks; vegetation in the catchment areas decreases Pradesh, K a r n a t a k a , and T a m i l N a d u is j u s t i f i e d by the because of o v e r - u t i l i z a t i o n ; subsequent erosion a n d flash expected returns f r o m increased stability a n d increased r u n - o f f cause siltation of the tank beds and breaches of area under tanks. tanks. (2) A l t e r n a t i v e sources f o r i r r i g a t i o n water have The concept of composite watershed management been developed, especially well water lifted by mechani- ( C W M ) on Alfisols proposes a system of r u n o f f - and cal devices. P u b l i c as well as private investments tend to erosion-controlling land management for enhanced favour these options over the traditional tank-irrigati o n groundwater recharge and sustained well irrigation. Thi s schemes. (3) T h e a d m i n i s t r a t i o n of i r r i g a t i o n tanks is concept was analyzed at 1 C R I S A T Center in a m o d e l i n g neglected, leading to increasingly inefficient water use exercise, and it was f o u n d to have considerable economic w h i c h in t u r n accelerates the redirection of private invest- p o t e n t i a l . F u r t h e r research o n C W M i s underway. ments. I r r i g a t i o n tanks are increasingly being treated as I n a d d i t i o n t o its economic p o t e n t i a l , C W M w i l l have common property resources, exploited without proper the socially desirable effect of p r o v i d i n g m o r e equitable management, a n d degraded. access to water. It w i l l also be beneficial to use the antici- Nevertheless, a survey of 32 tanks in A n d h r a Pradesh pated technology of solar- powered water l i f t i n g by a n d M a h a r a s h t r a shows that there is p o t e n t i a l f o r eco- ensuring relatively shallow water tables f o r effective n o m i c a l l y beneficial t a n k i r r i g a t i o n . There are tanks exploitation.

36 7. References

All India Economic Conference. 1937. Economic life of Hyde- Palanisami, K. 1981. Irrigation tank rehabilitation. New Irri- rabad. Hyderabad, India: Government Central Press. pp 117. gation Era 19(3):36-37.

Andhra Pradesh: Department of Information and Public Rela- Palanisami, K., and Easter William, K. 1984. Irrigation tanks tions. 1953. History and legend in Hyderabad (Dn). Hyde- of South India: management strategies and investment alterna- rabad, A.P. Department of Information and Public Relations. tives. Indian Journal of Agricultural Economics 34 (2):214-223.

Appadorai, A. 1936. Economic conditions in southern India Sharma, P.N. 1981. Optimization of small reservoir irrigation (1000-1500 A D ) . University of Madras pp.202-203. system for semi-arid tropics. Ph.D. thesis, University of Cali- fornia, Davis, California, USA. Baliga, B.S. 1960. Studies in Madras administration. Vol.11. Madras, India: Government of Madras. Smith, B.R. 1856. Irrigation in southern India. London, U.K: Elder and Co. Bandara, C.M. 1977. Hydrological consequences of agrarian change. Pages 323-339 in Green revolution? (Farmer, B.H., Vaidehi Krishna Murty, A. 1970. Social and economic condi- ed.), London, UK: The MacMillan Press. tions in eastern Deccan (1000-1250 A D ) . Madras, India: Kabeer Printing Press. Chambers, R. 1977. Men and water: the organisation and operation of irrigation. Pages 340-363 in Green revolution? Venkatram, B.R. 1985. Administrative feasibility of a tank (Farmer, B.H., ed.), London, UK: The MacMillan Press. irrigation authority. Economics Program Consultancy Report. Patancheru, A.P. 502 324, India: International Crops Research Coward, E. W., Jr. 1985. Traditional irrigation systems and Institute for the Semi-Arid Tropics. (Limited distribution). government assistance: current research findings from South- east Asia. Pages 1-30 in Traditional irrigation schemes and von Oppen, M. 1978. Instability of area and production under potential for their improvement. Proceedings of Irrigation tank irrigation in selected districts of Andhra Pradesh and Symposium, 1985, Deutscher Verband fur Wasserwirtschaft Tamil Nadu. Economics Program Discussion Paper no. 9. und Kulturbau vcrlagpaul parey (Mock, J.F., ed.), Hamburg, Patancheru, A.P. 502 324, India: International Crops Research Berlin Bulletin 9. Institute for the Semi-Arid Tropics (Limited distribution).

Davies, C.C. 1976. An historical atlas of the Indian peninsula. von Oppen, M . , and Subba Rao, K.V. 1980. Tank irrigation in 2nd edn. Madras, India: Oxford University Press. 73 pp. semi-arid tropical India. Part I. Historical development and spatial distribution. Economics Program Progress Report no.5. Engelhardt, T. 1984. Economics of traditional small-holder Patancheru, A.P. 502 324, India: International Crops Research irrigation systems in the S A T of South India. Ph.D. thesis, Institute for the Semi-Arid Tropics (Limited distribution). University of Stuttgart-Hohenheim, Federal Republic of Ger- many. 173 pp. von Oppen, M . , and Subba Rao, K.V. 1980. Tank irrigation in semi-arid tropical India. Part II. Technical features and eco• Gittinger, J.P. 1982. Economic analysis of agricultural pro- nomic performance. Economics Program Progress Report jects. 2nd ed. Baltimore, USA: John Hopkins University Press. no.8. Patancheru, A.P. 502 324, India: International Crops 505 pp. Research Institute for the Semi-Arid Tropics (Limited Gopal Reddy, Y. 1973. Agriculture under Kakatiyas of Waran- distribution). gal. Itihas, Journal of Andhra Pradesh Archives. 1: 56-65. von Oppen, M . , Subba Rao, K.V., and Engelhardt, T. 1983. Halcrow, Sir William. 1983. Small-scale solar-powered pump- Alternatives for improving small scale irrigation systems in ing systems: the technology, its economics and management. alfisols watersheds in India: a position paper. Presented at the World Bank, U N D P Project GLO/80/003. University of Minnesota/Colorado University/USAID Workshop on Water Management and Policy, 13-15 Sept 1983, Hanumantha Rao, C.H. 1968. Fluctuations in agricultural Khon Kaen, Thailand. Patancheru, A.P. 502 324, India: Inter- growth. Economic and Political Weekly 3(I-2):87-94. national Crops Research Institute for the Semi-Arid Tropics. Harris, D.G. 1923. Irrigation in India. London, UK: Oxford (Limited distribution). University Press. Yazdani, G. (ed.). 1960. The early history of the Deccan. Lon- Ludden, D. 1978. Ecological zones in the cultural economy of don, UK: Oxford University Press, Parts 1-4, pp. 8-9. irrigation in southern Tamil Nadu. South Asia 1(NS): 1-13. Yazdani, G. (ed) 1960. The early history of the Deccan. L o n - Madras Presidency Report. 1885. Manual of administration of don, UK: Oxford University Press, Parts 7-11, pp.667-680. the Madras Presidency. Vol. 1(A). pp. 319-406.

Meinzen-Dick, R.S. 1984. Local management of tank irrigation in South India: organization and operation. Cornell Stu- dies in Irrigation no. 3. Ithaca, New York, USA: Cornell University.

37 8 . A p p e n d i x

Appendix 1. Codes used for selected taluks and villages in Andhra Pradesh and Maharashtra where tanks were surveyed.

SI. Taluk Village1 no. District code Taluk name code Village name

1. Medak A Medak AA Borugpally 2. Medak Medak AB Rayanpally

3. Medak B Narsapur BA Narsapur 4. Medak Narsapur BB Rustumpet

5. Medak C Andole CA Andole 6. Medak Andole CB Annasagar

7. Medak D Siddipet DA Raghavapur 8. Medak Siddipet DB Rajakapet

9. Medak E Gajwel EA Gajwel 10. Medak Gajwel EB Pregnapur

11. Mahbubnagar F Mahbubnagar FA Tankara 12. Mahbubnagar G Wanaparthy GA Rajanagar 13. Mahbubnagar Wanaparthy GB Wanaparthy 14. Mahbubnagar H Gadwal HA Sangal 15. Mahbubnagar Gadwai HB Parmal

16. Mahbubnagar J Nagarkurnool JA Chirikipally 17. Mahbubnagar K Shadnagar KA Motighanapur 18. Mahbubnagar Shadnagar KB Raikal 19. Mahbubnagar L Atmakur LA Madepalli 20. Mahbubnagar Atmakur LB Erladinne

2 1 . Anantapur M Anantapur MA Singanamalla 22. Anantapur N Gooty NA Gooty 23. Anantapur Gooty NB Pathakotacheru

24. Kurnool P Dronachalam PA Veldurty 25. Kurnool Q Atmakur QA Siddapuram

26. Akola R Washmi RA Borala 27. Akola Washmi RB Shirupati 28. Akola S Mangrolpur SA Wathod 29. Akola T Murtizapur TA Karanza

30. Sholapur U Mangalwade UA Talsangi 31. Sholapur V Sangola VA Achakandi 32. Sholapur Sangola VB Chincholi

1. Villages AA to QA belong to Andhra Pradesh state, and RA to VB belong to Maharashtra state.

38 RA-00121 ICRISAT

International Crops Research Institute for the Semi-Arid Tropics Patancheru, Andhra Pradesh 502 324, India

ICR 86-0048 Printed at ICRISAT Center ISBN 92-9066-121-6