A. RESEARCH CONDUCTED IN EASTERN DRY AGROCLIMATIC ZONE

TITLE OF THE STUDY: Benefits of Tank Desiltation in Catchment and Command Area of Kolar District - An Economic Analysis

POST GRADUATE STUDENT INVOLVED:
Ms. Ramya R.D.
email: ramya_r_d@rediffmail.com

Preamble

Peninsular India has a large concentration of irrigation tanks. For centuries, these tanks supported agricultural development in rainfed regions. These water bodies are the common property resources owned and managed by village community. Tanks are multifunctional, providing surface and groundwater irrigation and serving water needs of rural households and livestock, besides silt fertilization. Thus, irrigation tanks constructed and maintained by human efforts strengthened agriculture in rainfed regions of south India. Of the total irrigation potential created, tank irrigation contributed 9.4 percent while ground water irrigation contributed to 38 percent during 1998-99.

With access to groundwater irrigation and shift in tank management from village community to government, factors such as siltation, unabated encroachment of tank beds for cultivation, infestation of weeds and inadequate maintenance have been the major issues for the deterioration of tank system.

With severe tank siltation in recent years, there is an increasing realization for rehabilitation of irrigation tanks. Realizing this, Government of Karnataka, initiated the program of desiltation on pilot basis in some of the tanks in Kolar, Bangalore and Tumkur districts in the Eastern Dry Zone.

Desiltation improves groundwater recharge and provides silt as manure and hence be accorded top priority. Recharge of groundwater through irrigation tank could reduce the irrigation cost by 50 percent on per acre basis. When the irrigation cost is considered on the basis of cost per acre-inch of groundwater, the advantage realized by farmers due to the impact of irrigation tank are by way of savings in cost per acre-inch of water used. These advantages are measured in terms of net returns per acre-inch of water (Rs.1866 as against Rs. 1577).

Due to the effect of tank desiltation, the number of functional wells and average age of wells in desilted tank village are higher than in non-desilted tank village. Hence the well failure problem can be controlled by groundwater recharge from desiltation program and also the yield of wells in desilted tank village was greater than in non-desitled tank village.

Objectives of the study

  1. Estimation of economic benefits of tank rehabilitation in command and catchment areas.

  2. To estimate the benefits due to conjunctive use of tank and groundwater.

  3. Estimation of financial feasibility of investment in tank rehabilitation.

Major Findings of the study

Feasibility of tank rehabilitation

B. RESEARCH CONDUCTED IN NORTHERN DRY AGROCLIMATIC ZONE

TITLE OF THE STUDY: Optimal Extraction of Groundwater Resource in Canal, Tank and Well Irrigation Commands in Karnataka- Application of Control Theory

POST GRADUATE STUDENT INVOLVED:
Sri. Rajendra. A.
email: rajvagta@rediffmail.com / rajvagta@yahoo.co.in

Preamble

Property rights to groundwater are obscure. However, as groundwater is indispensable for irrigation, in the absence of alternative sources of irrigation, farmers are desperate in searching alternative sources of groundwater. In the process, farmers in all likelihood cause cumulative interference by drilling additional well(s) and/or deepening existing well(s). In this study, the pattern of extraction of groundwater is being studied under three situations where (i) irrigation wells are located uninfluenced by recharge from any surface water body (GWSI), (ii) irrigation wells are located under the command of tank irrigation (GWTI) and (iii) irrigation wells are located under the command of canal irrigation (GWCI). It has been found that farmers in GWSI have relatively low relative sustainability index since, they compare their economic performance with farmers who have reaped the highest net return per rupee of water.

It has also been found that GWCI farmers with access to larger volume of groundwater, realized higher net return per rupee of groundwater of Rs. 5.30 (Even though high groundwater users of GWTI realized a net return of Rs.5.8 per rupee of groundwater, the net return of Rs. 5.30 per rupee of groundwater realized by GWCI farmers is taken as RSI base, since the recharge potential of GWCI is larger than GWTI and hence the net return of Rs. 5.30 per rupee of groundwater under GWCI is more sustainable than the net return of Rs. 5.80 under GWTI ) and thus have relatively larger relative sustainability index (RSI) (of 1.00). There are no compelling reasons to disbelieve that GWSI farmers with low RSI will not strive towards the performance of farmers in GWCI and in the process contribute to cumulative well interference externality. This study provides an optimal path of groundwater extraction considering the cost of extraction as well as the externality cost.

Objectives of the study

  1. To document the pattern of groundwater extraction and cropping pattern.

  2. To document the pattern of investment in irrigation wells.

  3. Examine the resilience and strategies of farmers in response to economic scarcity of water in the framework of optimal control theory in exclusive commands of canal, tank, and well irrigation.

  4. Valuation of synergistic role of canals and tanks in groundwater recharge and associated equity implications.

Major Findings of the study

Implications

C. RESEARCH CONDUCTED IN CENTRAL DRY AGROCLIMATIC ZONE

TITLE OF THE STUDY: Valuation of Synergistic Role of Canals and Tanks in Groundwater Recharge in the Framework of Optimal Control Theory

POST GRADUATE STUDENT INVOLVED:
Ms.Chaitra B.S.
email: chaitra_ballal@rediffamail.com

Preamble

The groundwater extraction in pockets of Central Dry Zone dominated by coconut crop, does not seem to be exploitative in nature. This is reflected by the modest amortized cost of groundwater irrigation ranging from Rs. 156 per acre-inch in GWSI (sole wells), Rs. 104 per acre-inch in GWTI (groundwater extraction under tank command) and Rs. 73 per acre-inch in GWCI (groundwater extraction under canal command). The net return per rupee of groundwater is the highest in GWCI (Rs. 4.7), followed by GWTI (Rs. 3.22) and GWSI (Rs. 1.83).

 

The economic access of GWCI farmers was higher by 118 percent over GWSI, and that of GWTI was higher by 50 percent over GWSI. The net returns per acre-inch of groundwater is Rs.337 in GWCI followed by Rs.332 in GWTI and Rs.286 in GWSI. It was found that GWSI had greater diversification of crops compared with GWTI and GWCI. Area under groundwater irrigation formed 85 percent of gross irrigated area in GWTI and 65 percent in GWCI. The focus of the study is to analyse the synergistic effects of canals and tanks in groundwater recharge and to estimate the optimal path of groundwater extraction in Tiptur and Turuvekere Taluks of Tumkur district.

Objectives of the study

  1. Estimation of optimal path of groundwater extraction under exclusive canal, tank and well irrigation commands.

  2. Valuation of synergistic role of canals and tanks in groundwater recharge and associated equity implications.

  3. Examination of emerging economic opportunities for farmwomen in groundwater irrigation.

Major Findings of the study

  • In GWSI optimal extraction extends well life by seven years and net additional benefits over myopic extraction was Rs.36998, while in GWTI (GWCI) optimal extraction enhances the well life by 17 (24) years and present value of net additional benefits were Rs. 85840 (Rs.163653).

  • In GWTI optimal extraction enhances the well life by 17 years and present value of net additional benefits were Rs. 85840.

  • In GWCI optimal extraction enhances the well life by 24 years and present value of net additional benefits were Rs. 163653.

  • The cropping pattern was mainly dominated by commercial perennial coconut plantations in GWSI (88 percent) compared to GWTI (55 percent) and GWCI (61 percent). The paddy crop was prominent in both GWTI (14 percent) and GWCI (20 percent).

  • In the study area, 80 percent of irrigation wells were borewells. Dug wells and Dug- cum- bore wells in GWSI are completely Un-fructuous. On the contrary, all the dug-cum-borewells, 60 percent of dug wells were productive in GWTI, while in GWCI all the dug wells and 66 percent of dug -cum-bore wells were functional. In the case of borewells, rate of failure was higher in GWSI (35 percent) compared with GWTI (12 percent) and GWCI (10 percent).

  • Depth of the bore wells was the highest in GWSI (300 feet) followed by GWTI (200 feet) and GWCI (180 feet). Which reflects relatively higher water table in canal and tank command due synergistic effect of groundwater recharge from surface water bodies.

  • Average yield of wells were comparatively higher in GWCI (2794 GPH) and GWTI (2360 GPH) than GWSI (1692 GPH) due to recharge from surface water bodies.

  • Proportion of area under groundwater irrigation to gross irrigated area was 85 percent and 65 percent in tank command (GWTI) and canal command (GWCI) respectively, thus emphasizing how vital groundwater irrigation is even in command areas of tanks and canals.

  • Net returns from groundwater irrigated area were accounted for 88 percent (67 percent) of total net returns in GWTI (GWCI) and the rest were from surface water irrigated area.

  • Net returns obtained per acre of gross irrigated area was found to be highest in the case of GWCI (Rs.4582), followed by GWTI (Rs.4096) and GWSI (Rs.2915).The net income received per acre inch of water in GWCI (Rs.337) was the highest followed by GWTI (Rs.332) and GWSI( Rs.286).Thus, synergistic effect of surface water bodies facilitated realization of higher incomes over GWSI due to recharge of wells, which dampen the failure of wells.

  • Cropping intensity and irrigation intensity was found to be increasing from GWSI to GWTI to GWCI.

  • The amortized cost per well was higher by 25 percent and 35 percent for GWSI farmers compared with GWTI and GWCI farmers. While, amortized cost per functioning well in GWSI was nearly twice (Rs.8067) than that of GWCI (Rs.4850).

  • In GWTI (GWCI) amortized cost per acre-inch of groundwater was lower by 34percent (54 percent) compared with GWSI which reflects positive externality due to synergistic role of canals and tanks in groundwater recharge.

  • The failure rate of irrigation wells being modest in GWTI (12 percent) and GWCI (10 percent), the externality cost per well is Rs.387 and Rs.422 respectively, while in GWSI it is Rs.2051.

  • The synergistic effect of surface water bodies has reduced the investment per functioning well to the extent of 27 percent and 28 percent for GWTI and GWCI farmers respectively compared with GWSI farmers.

  • Economic access in terms of groundwater used per rupee of amortized cost was relatively higher for GWCI farmers (0.0137 acre-inches) than GWTI (0.0096 acre- inches) and GWSI (0.0064 acre -inches) farmers.

  • In sole well regime (GWSI). HWU incurred relatively lower (Rs.132) amortized cost per acre- inch of water than MWU (Rs.167) and LWU (Rs.156). Thus, HWU had greater economic access (0.00759 acre- inches) compared with LWU (0.00641 acre- inches) and MWU (0.00591 acre - inches).

  • In GWSI, HWU realized higher net returns (Rs.309) per acre- inch of water compared with MWU (Rs.274) and LWU (Rs.288).

  • In GWTI, LWU realized highest net returns (Rs.346) per acre-inch of water followed by MWU (Rs.287) and HWU (Rs.241).

  • In GWTI, MWU had greater economic access to groundwater (0.0102 acre inches) than HWU (0.0098) and LWU (0.0089 acre inches) as cost incurred per acre- inch of groundwater was lowest for MWU (rs.98) followed by HWU (Rs.102) and LWU (Rs.113).

  • In GWCI, eventhough HWU had greater economic access to groundwater ,net returns per acre inch of water was higher for LWU to the extent of 7 percent (45 percent) compared with MWU(HWU).

  • Increased well life, negligible well failure and increase in the water yield of the wells are some of the main physical impacts of the synergistic effect of surface water bodies in groundwater recharge. The economical impacts are in terms of lower irrigation cost and higher income from their irrigated lands.

  • Percentage of woman labour employed was higher (34 percent) in GWSI compared with GWTI (31 percent) and GWCI (25 percent) as crop diversity was better in GWSI. While percent female labour employed in surface water irrigated farms was higher because, large portion of cropped area was under paddy crop where as in groundwater irrigated area, cropping pattern was dominated by coconut gardens.

Implications

  • As discounted net returns and well life are improving in the optimal extraction compared with myopic extraction, withdrawal of groundwater based on optimal control results in sustainable extraction.

  • Rainwater harvesting for recharging groundwater in non-tank or canal command reduces the groundwater extraction cost. Hence efforts be made in this direction.

  • Farmers need to be motivated to invest on backstop technologies like drip irrigation rather than investing on new wells which is increasingly becoming a risky venture.

  • Since installation of electrical meter on IP sets is inviting resistance from farmers, water meter can be fixed initially to educate farmer regarding the volume of extraction of groundwater on their farm. This helps in budgeting groundwater for different crops. Later, farmer can be convinced to defray electrical charges.

This research paper is published in Water Policy Journal, IWA Publishing, 2005.

Click here to Download this paper: Chaitra, B.S. and Chandrakanth, M.G. (2005), Optimal extraction of groundwater for irrigation: synergies from surface water bodies in tropical India.Water Policy Journal, IWA Publishing, 7: 597-611. .

 

D. RESEARCH CONDUCTED IN NORTH EASTERN DRY AGROCLIMATIC ZONE

TITLE OF THE STUDY: Dynamics of Access to Groundwater in Exclusive Commands of Canal, Tank and Well Irrigation in Karnataka - an Optimal Control Theory Approach

POST GRADUATE STUDENT INVOLVED:
Sri. Bittira Ullas Kusha
email: email: kusha@yahoo.co.in

Preamble

The groundwater extraction in pockets of North Eastern Dry Zone dominated by cotton, does not seem to be exploitative in nature. This is reflected by the modest amortized cost of groundwater irrigation ranging from Rs. 156 per acre inch in GWSI (sole wells), Rs. 79 per acre inch in GWTI (groundwater extraction under tank command) and Rs. 82 per acre inch in GWCI (groundwater extraction under canal command). The net return per rupee of groundwater is the highest in GWCI (Rs. 1.25), followed by GWTI (Rs. 1.31) and GWSI (Rs. 1.56). The economic access of GWCI farmers was higher by 62 percent over GWSI, and that of GWTI was higher by 64 percent over GWSI. The net returns per acre inch of groundwater is Rs. 128 in GWCI followed by Rs.121 in GWTI and Rs. 161 in GWSI. It was found that GWSI had greater diversification of crops compared with GWTI and GWCI. Area under groundwater irrigation formed 82 percent of gross irrigated area in GWTI and 88 percent in GWCI.

Property rights to groundwater are obscure. However, as groundwater is indispensable for irrigation, in the absence of alternative sources of irrigation, farmers are desperate in searching alternative sources of groundwater. In the process, farmers in all likelihood cause cumulative interference by drilling additional well(s) and/or deepening existing well(s). In this study, the pattern of extraction of groundwater is being studied under three situations where (i) irrigation wells are located uninfluenced by recharge from any surface water body (GWSI), (ii) irrigation wells are located under the command of tank irrigation (GWTI) and (iii) irrigation wells are located under the command of canal irrigation (GWCI). It has been found that farmers in GWSI have relatively low relative sustainability index since, they compare their economic performance with farmers who have reaped the highest net return per rupee of water. It has also been found that GWCI farmers with access to larger volume of groundwater, realized higher net return per rupee of groundwater of Rs. 1.56 and have a comparable relative sustainability index (RSI) (of 1.00). The RSI of GWSI farmers is 0.8 and that of GWTI farmers is 0.84. This shows that farmer in all the three situations are closer to realizing the same net return per rupee of groundwater. This is an exception to other two studies reported by Rajendra and Chaitra in this report.

Objectives of the study

  1. Social mapping of groundwater extraction path with equity consideration.

  2. Estimation of the optimal control path of groundwater extraction under exclusive commands of canal, tank and well irrigation.

  3. Estimation of the value of groundwater for irrigation and compare it with different prices charged for groundwater in groundwater markets.

Major Findings of the study

  • In GWSI, 77% of borewells were functioning and in GWTI, 82 per cent of borewells were functioning. In GWCI, 88 per cent of borewells were functioning. Thus the failure rate of borewells was the highest (23 per cent) in sole well situation as there is limited recharge.

  • In GWSI, 67 per cent of dug wells were functioning and in GWTI, 75 per cent of dug wells were functioning and in GWCI, 91 per cent of dug wells were functioning. Thus the failure rate of dug wells was the highest (33 per cent) in sole well situation as there is limited recharge.

  • Yield of borewell ranged from 2500 to 3300 gallons per hour (GPH) while that of dug wells ranged from 925 to 1330 GPH.

  • In tank and canal command 81 per cent and 54 per cent of Gross Irrigated Area (GIA) is irrigated by groundwater respectively.

  • Since groundwater irrigation formed more than 75 per cent of irrigated area in all the three situations, farmers cultivated mainly light water crops. In the GWSI, cotton occupied 33 per cent of gross irrigated area followed by jowar (20 per cent), sorghum (14 per cent), maize (13 per cent) and groundnut (13 per cent). In the GWTI, cotton occupied 38 per cent of gross irrigated area followed by maize (17 per cent), sunflower (16 per cent), groundnut (12 per cent) and paddy (5 per cent). In the GWCI, cotton occupied 40 per cent of gross irrigated area followed by maize (25 per cent), jowar (14 per cent), sunflower (14 per cent).

  • In GWSI, low water users (LWU) formed 50 per cent of all users. In GWTI, high water users (HWU) formed 53 percent and in GWCI, high water users (HWU) formed 80 per cent.

  • There was inequality in access to water and inequality in area irrigated. Tank and canal command farmers had improved access to surface water and devoted more than 60 per cent of GIA for water intensive crops. Sole well irrigation farmers were more diversified compared to tank and canal command farmers.

  • Rate of failure of bore wells was the highest in GWSI (23 per cent) compared with GWTI (18 per cent) and GWCI (12 per cent ). In the case of dug wells, 33 per cent of dug wells were non- functioning in GWSI.In GWTI and GWCI failure rate among dug wells was 25 per cent and 9 per cent respectively.

  • Of the groundwater used per acre, groundwater formed 83 per cent in GWTI and 97 per cent in GWCI and the total water used by GWCI farmers the highest (11.76 acre inches) followed by GWTI (9.40 acre inches) and GWSI (8.88 acre inches) farmers.

  • The highest net returns per acre inch of was realized by GWSI farmers (Rs.161) followed by GWCI (Rs.128) and GWTI (Rs.121) farmers.

  • Cropping intensity (irrigation intensity) in GWSI was 186.35 per cent (213.75 percent) compared with GWTI and GWCI where it was 180.76 (256.42) pert cent and 155.78 (212.20) percent respectively.

  • Even though number of wells possessed by GWSI farmers was higher (54) compared to GWTI (46 ) and GWCI (43 ) farmers, there was an even distribution of functioning wells among farmers of different irrigation regimes and this difference was mainly due to high well failure rate in the GWSI where there is no recharge support from surface water bodies.

  • The economic access to groundwater is reflected in terms of groundwater used in acre-inch per rupee of amortised cost. This is relatively higher for GWCI (0.0128) farmers compared with GWTI (0.0127) and GWSI (0.0078) farmers.

  • Farmers were classified based on water use per acre, those using 11.5 acre inches as low water users, 11.5 o 13.5 acre inches as medium water users and more than 13.5 acre inches as high water users.

  • Amortised cost of irrigation per acre inch of groundwater was high in GWSI (Rs.128.4) compared to GWTI (Rs.78.91) and GWCI (Rs.78.29). The economic access to groundwater was less in GWSI (0.0078) compared to GWTI (0.0127) and GWCI (0.0128).

  • The annual net returns from groundwater per acre inch of water across different water use systems,GWSI realized higher returns of Rs.161 compared to GWTI (Rs.104) and GWSI (Rs.124).

  • In GWSI optimal extraction extends well life by 12 years and net additional benefits over myopic extraction was Rs.12421.In GWTI optimal extraction enhances the well life by 14 years and present value of net additional benefits were Rs.90266. In GWCI optimal extraction enhances the well life by 26 years and present value of net additional benefits were Rs.86707.

  • The number of water sellers and water buyers was higher in GWSI, compared to GWTI and GWCI.

  • The groundwater market structure was a bilateral monopoly, with similar pricing across all the three groundwater situations with free entry and exit.

  • The economics of groundwater transaction indicates that, groundwater irrigation from the well owners had greater impact on productivity of paddy, as a greater proportion of groundwater was allotted towards cultivation of paddy. The productivity of paddy was higher for groundwater sellers by 25 per cent over groundwater buyers.

  • The water markets are influenced by both demand and supply induced factors. The demand for water is a function of the price of water, technology adopted and returns from crops. Similarly, supply factors influencing groundwater include availability of surplus water for marketing, extraction. Further, small and fragmented holdings were also responsible for water sale, which acted as a constraint to expand the irrigation area.

Implications

  • The cost per acre inch of groundwater is lower in canal regime due to synergistic effect of surface water recharge. It is imperative that the optimal extraction will not only promote sustainability of groundwater extraction, but also dampens the groundwater cost.

  • The projected net returns under optimal rule are increasing over the life horizon of irrigation well. This optimal extraction is around 35 acre-inches per well per annum. Obviously this calls for coping mechanisms inter alia reduction in gross irrigated area with existing cropping pattern or installation of water saving devices like drip/ sprinkler irrigation.

  • Farmers need to be motivated to invest on back stop technologies like drip / sprinkler irrigation rather than investment on new wells which are increasingly becoming risky venture.

  • There has been increased exploitation of groundwater in this region. This has several repercussions on sustainability of groundwater use. Hence to promote sustainability of groundwater use and thus increasing accessibility of water to farmers, efforts be made to improve groundwater recharge.