Science, Technology and Development ISSN : 0950-0707 Problems Involved in the Sustainable Water Supply from Annamayya and Mallemadugu Reservoirs in Kadapa and Chittoor Districts of Galeru-Nagari Sujala Sravanthi (GNSS) Project, Andhra Pradesh, India R Balaram* Department of Geology Sri Venkateswara University, Tirupati, Andhra Pradesh, India *Corresponding Author S. Ramanaiah Department of Geology Sri Venkateswara University, Tirupati, Andhra Pradesh, India R. Jagadiswara Rao Retired Principal and Professor of Geology Sri Venkateswara University, Tirupati, Andhra Pradesh, India Abstract – This paper describes the Galeru-Nagari Sujala Sravanthi (GNSS) Project under construction since 1988 to import Krishna River water through Galeru River in Kurnool District to Kadapa and Chittoor Districts, Andhra Pradesh, India by limiting the scope of work to Annamayya Reservoir southeast of Pulangeru River – a tributary of Cheyyeru River in Kadapa district and Mallemadugu Reservoir at Karakambadi village in Chittoor district and the adjoining Tirupati Smart City for sustainable development of water resources of good quality for various uses. Keywords – Water Supply, Surface Water, Ground Water, Water Supply, Gravity Flow, Pumping, Sustainability, Water Quality, Floods, Droughts. I. INTRODUCTION DESCRIPTION OF GNSS PROJECT Government of Andhra Pradesh (AP) took up the Galeru Nagari Sujala Sravanthi (GNSS) Project as per Government Order (GO) dated 22 Sep 1988 to draw 40 TMCft surplus flood water of Krishna River a year from the foreshore of Srisailam Reservoir during August to November every year through Srisailam Right Bank Canal (SRBC) system up to Gorakallu Reservoir and thereafter through an independent flood flow canal canal together with tunnels to feed several reservoirs en route. The water so stored would be used to irrigate one crop by gravity flow in 1.55 lakh acres in Kadapa District, 1.035 lakh acres in Chittoor District and 1.5 thousand acres in Nellore District. As per Government Order (GO) dated 26 Aug 2020, administrative sanction was accorded for over Rs Volume X Issue III MARCH 2021 Page No : 282 Science, Technology and Development ISSN : 0950-0707 10,300 crores for various irrigation projects in Rayalaseema region with lion’s share earmarked to lift water from Gandikota reservoir to a link canal together with tunnels for flow by gravity till Nagari River (Fig 1). The scope of our work is confined to the existing Annamayya Reservoir (Sagar) and Mallemadugu (Mallimadugu) Reservoir together with the Tirupati Smart City. The masonry dam of Annamayya Medium Irrigation Reservoir was constructed across Cheyyeru River downstream of its confluence with Mandavi River at Badanagadda village in Rajampeta Mandal during 1981-2001 at a cost of Rs. 60.44 crores. It is designed to irrigate 13,000 acres in Khariff, 6,500 acres in Rabi and 3,000 acres for stabilization of wet crops under tanks, besides providing drinking water of 190 mcft of water to 140 habitations in Rajampet mandal and 100 mcft to 75 habitations in Kodur mandal by seeking funds under Govt of India's Accelerated Irrigation Benefits Programme (AIBP) for agrarian-distressed districts. The Mallemadugu reservoir was constructed across Rallakalva River with a full reservoir capacity of 505 acres (204.39 ha) and a gross storage capacity of 181 mcft (5.13 million cu m). Its command area is 3954 acres (1600 ha), which includes a direct ayacut of 267 acres (108 ha) and an indirect ayacut of 3687 acres (1492 ha) irrigated by 15 system tanks. Fig 1: Schematic map showing how the Gandikota reservoir water would be lifted into link canals with tunnels and balancing reservoirs to flow by gravity up to Nagari River. Volume X Issue III MARCH 2021 Page No : 283 Science, Technology and Development ISSN : 0950-0707 ANNAMAYYA PROJECT Construction of Annamayya Project posed several problems (Sudarsana Raju, 1989, 1995). Although Bairenkonda Quartzite exposed along the dam axis and the spillway provided good stability to the dam, the reservoir could hold no water at all. An investigation revealed that the entire reservoir water was percolating as deep groundwater owing to the leaky nature of the underlying cavernous dolomite limestone and shale. A subsurface dam with diaphragm wall was then constructed along the dam axis and the spillway. By this, the reservoir could be made perennial round the year to some base level. Thus from the historical Google Earth Pro images generated, the reservoir was not seen at all in the imageries captured on or before 31 Dec 2000. Only after the construction of the subsurface dam, the imageries captured on or after 31 Dec 2001 only show the reservoir (Fig 2). Further investigations revealed that there was leakage of water into the underground as deep groundwater through cavernous dolomite limestone and shale (karst formation) occurring in a large area around the reservoir preventing any further rise of water level in the reservoir. As a result, no water flowed in the already constructed Right Main Lined Canal of 23.63 km length from the reservoir. The Cheyyeru Riverbed in the downstream looks dry most of the time but for a minor meandered flow for a few km downstream of the dam. The riverbed both in the upstream and downstream of the Annamayya reservoir looks barren of water exposing mostly dry sand with shallow groundwater flowing beneath the channel emerging as surface water only in the Annamayya reservoir and the downstream Somasila reservoir. Fig 2 is the Google Earth Pro image of the Cheyyeru River as on 7 Apr 2019 showing the dry lined supply channel of the Project with extensive crop growth round the year in and around the command area using deep wells. The cultivators in the region were irrigating the arable land on either side of the Cheyyeru River earlier through spring channels by gravity flow and lift (or doruvu) wells in the riverbed, now replaced by shallow tube wells popularly known as filter points. Although the command area of the Annamayya Project gets no reservoir water through gravity flow, the enterprising cultivators in the region could tap deep groundwater through bore wells constructed by rotary percussion method using Down-The-Hole (DTH) rigs to irrigate their lands round the year. This deep groundwater remained sustainable owing to round-the-clock seepage of Annamayya reservoir water through karst formations. Fig 2: Google Earth Pro Image of Annamayya Reservoir as on 7 Apr 2019. Volume X Issue III MARCH 2021 Page No : 284 Science, Technology and Development ISSN : 0950-0707 Fig 3 shows how the riverbed downstream of the Annamayya reservoir looks. Although the Bairenkonda Quartzite with shale interactions occurs along the flanks of Annamayya reservoir with hillocks covered with shrubby forest cover, the riverbed is occupied by a thick substrate of crushed stone of various dimensions interspersed by pools of freshwater where fish grow. Under the influence of cyclonic storms in the Bay of Bengal, there can be cloudburst rains in the catchment generating flash floods for a few days both in the upstream and downstream of the existing reservoirs (Figs 4 and 5). Fig 3: Photo of Cheyyeru Riverbed downstream of Annamayya Dam Fig 4: Photo taken on 3 Oct 2020 showing short-duration flood flow along the spillway of the Annamayya Dam. Volume X Issue III MARCH 2021 Page No : 285 Science, Technology and Development ISSN : 0950-0707 Fig 5: Photo taken on 3 Oct 2020 showing Nandalur-Rajampet Rail Bridge with good water spread shown for short duration in the riverbed serving as a source of recreation. MALLEMADUGU PROJECT Mallemadugu reservoir is an existing reservoir in an area of 505 acres (204.39 ha) constructed across the Rallakalva (Rallamadugu) River with a capacity of 181 mcft to irrigate a direct ayacut of 267 acres (108 ha) and an indirect ayacut of 3687 acres (1492 ha) irrigated by 15 system tanks. In order to store and use the GNSS water expected to flow by gravity from Gandikota lift after some years, the Govt of AP approached the Union Ministry of Environment and Forests for clearance of 1829 acres (740 hectares) of forestland for a 3-fold increase of the Mallemadugu reservoir’s capacity and construction of a new Balaji Sagar Reservoir of 4 tmcft capacity nearby to provide additional drinking water needs of both Tirupati and Tirumala. After over one decade, the Union Ministry consented to the AP Govt’s proposal and asked to pay compensation of Rs 75 crores (Nethaji, 2019). Once the GNSS water fills these reservoirs to the full, there would be seven-fold increase in water filling up these reservoirs. Mallemadugu reservoir as on now carries very little water as shown in Fig 6. But, when it receives cloudburst rains under the influence of cyclonic depressions in the Bay of Bengal during North East monsoon, it looks as in Fig 7 and soon gets back to its normal condition after inflicting extensive flood disaster of short duration in the downstream. Fig 6: Nearly Dry Mallemadugu Reservoir bed. Volume X Issue III MARCH 2021 Page No : 286 Science, Technology and Development ISSN : 0950-0707 Fig 7: Heavy outflows to Rallakalva River and Rallamadugu in Yerpedu mandal downstream of Mallemadugu reservoir on 26 Nov 2020 It is pertinent here to mention the media report on the flood disaster caused by this flow in the downstream (New Indian Express, 2020). Three farmers who went to retrieve their motors from the banks of Rallakalva River in spate on the morning of 26 Nov 2020 were washed away to Rallamadugu in Yerpedu Mandal, Chittoor District. Two of them could be rescued by the National Disaster Response Force (NDRF) Personnel in a speed boat accompanied by the Chandragiri MLA and Government Whip Chevireddy Bhaskar Reddy, who received laurels from the AP Chief Minister YS Jaganmohan Reddy (Fig 8).