General Resource Status of Dhone and Kalyandurg
Total Page：16
File Type：pdf, Size：1020Kb
General resource status 4 of Dhone and Kalyandurg 4.1 Groundwater resources Well statistics Figures 18 and 19 show the locations of wells in Kalyandurg and Dhone respectively. These data were collected as part of the well survey carried out by the Andhra Pradesh Groundwater Department. The wells surveyed included open wells, inborewells and borewells. Wells that were defunct but still intact were included in the survey, whereas open wells that had been completely abandoned and borewells that no longer had headworks were not included in the survey. These figures show the preference for siting wells near to drainage lines. In general, the absence of wells in certain areas can be explained in terms of either unfavourable geological conditions or poor groundwater quality. 40 Figure 18. Location of wells in Kalyandurg Figure 19. Location of wells in Dhone 41 Figure 20. Well construction timeline for Kalyandurg 250 200 150 100 Well construction (wells/year) 50 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Openwell Inborewell Borewell Figure 21. Well construction timeline for Dhone 250 200 150 100 Well construction (wells/year) 50 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Open well Inborewell Borewell Figures 20 and 21present the number of of the century are, therefore, misleading and the wells of different types constructed during the reality was that the rate of well construction was 20th Century in Kalyandurg and Dhone more uniform during these decades. In contrast, respectively. As information on date of peaks during the last 25 years were related construction of wells was elicited in part from primarily to government grants and loans that local villagers, information for the first part of encouraged sudden spurts in well construction. the century is presented on a decadal basis. The peaks in well construction during the first part 42 The following points relate to the history and pattern of well construction in these mandals: Box 8. Driving forces behind well construction . There has been a dramatic increase in well construction and groundwater extraction Factors that have encouraged the increase during the last 15 years primarily for in well construction include: groundwater-based irrigation; . Official statistics on well construction . Markedly higher and more reliable underestimate the current number of wells returns that farmers get from by a factor of two. This finding has major irrigated cropping as opposed to implications for estimation of groundwater rainfed cropping; draft that is based on well statistics . Government programmes that have (e.g. the GEC-97 Methodology); provided grants or soft loans for well . At the mandal level, there was reasonable construction; agreement between water audit well . Government policies that have led to statistics and statistics provided by Transco the cost of electricity being subsidised; on the number of pump connections; . Improved drilling technology and . In recent years, groundwater extraction per competition between contractors. well has increased substantially as a result Both have ensured that the cost of of the availability of submersible pumps borewell construction is relatively low; and electricity; . Competition for water between . The shift in well construction from open farmers accessing the same aquifer. wells to borewells, in Kalyandurg in This has led to competetive particular, represents a shift from deepening of wells and/or construction groundwater extraction that exploited of new borewells. shallow regolith aquifers to extraction from deeper bedrock aquifers. Figure 22 presents the status of wells surveyed in Kalyandurg. It can be seen that in early 2001, 31% of the wells surveyed had either failed completely or were unreliable. The wells that were completely defunct were predominantly open wells. Similar analysis of survey data for Dhone indicated that less than 1% of wells were defunct and 7% of wells failed routinely. Although the number and density of wells in Kalyandurg and Dhone was similar, this difference in well failure was explained by the fact that levels of groundwater extraction for irrigation, domestic use and livestock were around 30% higher in Kalyandurg as compared to Dhone. In both mandals indications were that competition for water between farmers was intensifying. The prognosis is therefore for an increase in well failure in both mandals and a more marked shift from open well to borewell construction in Dhone. Figure 22. Well failure rates in Kalyandurg 43 Domestic water use Net groundwater extraction for irrigation, rainfall for Kalyandurg and Dhone respectively. domestic and livestock use for Kalyandurg and If annual domestic and livestock use are Dhone was estimated at 11.0% and 8.4% of mean considered in terms of average annual annual rainfall respectively. As the Andhra Pradesh groundwater recharge, it is apparent that Groundwater Department estimate of currently 6% and 8% of average annual recharge groundwater recharge in this area is approximately is being used to meet these needs in Kalyandurg 10% of annual rainfall, this suggests that current and Dhone respectively. Taking a population levels of extraction in Kalyandurg are not growth rate of 2.5% and assuming that current sustainable. Analysis of villagewise groundwater per capita levels of water use are maintained, it extraction showed large differences between can be estimated that groundwater extraction for villages in both mandals. These were attributed in domestic and livestock use will double in the next part to more favourable hydro-geological 30 years to 12% and 16% of average annual conditions in some villages and in part to groundwater recharge. In many village areas, variations in the historical pattern of development meeting this increased demand will not be of both ground and surface water resources. This possible without a commensurate reduction in finding, coupled with the results of analysis of groundwater use for irrigation. There is cadastral information, illustrates the fact that there considerable variability in domestic water use is neither equitable access to irrigation between with some revenue village areas (e.g. Dhone town, villages nor between households within villages. Kalyandurg town and Duradakunta) having Figure 23 gives an indication of the number of current levels of use well in excess of 20% of wells per revenue village in Kalyandurg that were average annual recharge. being used as sources of water for irrigation and domestic supply. As might be expected, the number of “irrigation” wells now far exceeds the number of “domestic supply” wells. Annual groundwater extraction for domestic and livestock use was estimated at 0.6% and 0.8% of annual Figure 23. Use of wells in Kalyandurg 44 Figure 24. Automatic groundwater level data from Dhone Groundwater levels Figure 24 presents data from two of the three watershed development programmes. automatic groundwater level recorders installed in Information showing: changes in access and Dhone as part of the National Hydrology Project. entitlements to water, changes in time taken by Although these provide a useful insight into the women and children to fetch and carry water, dynamics of groundwater level change, the data are changes in the number of villages requiring not easy to interpret without accurate information tankers or with water markets and changes in on levels of groundwater extraction in the irrigated cropping intensity provide more immediate vicinity of the observation wells. At compelling evidence as to whether or not best, groundwater levels are a crude and unreliable programmes are successful. indicator of the localised success (or otherwise) of 45 Figure 25. Groundwater level data from Golla and Data from the groundwater level Kalyandurg (Source: Andhra Pradesh Groundwater recorders at Golla and Kalyandurg Department) (see Figure 25) do not correlate well 300 with the findings of the Groundwater Department’s survey in this mandal. 250 In the case of Golla, this can be explained by the fact that the recorder is sited ) 200 in a locality with a relatively low level of groundwater extraction. Also the actual 150 site of this recorder (as with many others) was chosen primarily on the basis of the 100 Monthly rainfall (mm rainfall Monthly security of the equipment. The wider implication is that water-level recorder 50 information should be used with extreme caution when assessing regional impacts 0 Jan-97 Jul-97 Jan-98 Jul-98 Jan-99 Jul-99 Ja n-00 Jul-00 Ja n-01 Jul-01 Ja n-02 Jul-02 of, say, watershed development. 300 250 Small tank near Gosanapalli, Dhone 200 150 100 Monthly rainfall (mm) 50 0 Jan-97 Jul-97 Jan-98 Jul-98 Ja n-99 Jul -99 Ja n-00 Jul -00 Ja n-01 Jul-01 Ja n-02 Jul-02 Goat drinking from a hand pump Box 9. Electricity tariffs for irrigation wells One-off connection charges include: a Rs.25 application fee, a Rs.100 security deposit and a development fee of Rs.1,000 per HP of the pump. Once connected, the electricity tariff is an annual charge that depends only on the rating of the pump. Pumps with ratings of up to 3 HP, 3-5 HP, 5-10 HP and more than 10 HP have annual tariffs of Rs.225, Rs.375, Rs.475 and Rs.575 respectively. Farmers with small and marginal holdings can opt for unit payment or optional tariff of Rs.0.2 per unit up to 2,500 units and Rs.0.5 for consumption in excess of 2,500 units. 46 Figure 26. Stage of groundwater development in Kalyandurg Figure 26 presents stage of groundwater development in Kalyandurg as estimated by the Andhra Pradesh Groundwater Department using data collected during the Water Audit survey. This figure shows that groundwater development has reached the “critical” or “over-exploited” stage in two thirds of the villages in this mandal. Subsequent and more detailed water-budget investigations carried out by the DFID-supported WHiRL project in four villages in Kalyandurg supported the findings presented here.