Geography
The Bhima River on which the Ujjani Dam has been built rises from Bhimashankar hills in the Western Ghats, also known as the Sahyadri hill range. The river flows for a length of till it meets the Krishna River (one of the two major river systems in Maharashtra, the other being theClimate
The basin experiences tropical monsoon climatic conditions. The rainfall is dictated by the southwest monsoon, which varies from (from South to North) near the North–South trending mountain range of the basin but drastically drops to within a distance of towards the east. The average annual precipitation of the basin above the dam in the Upper Bhima River Basin (UBB) has been assessed as out of which (87%) occurs during the four monsoon months (mid June to mid September). Thereafter, the basin falls under the rain shadow area towards the east with rainfall incidence ranging between and is thus under drought conditions quite frequently.Hydrology
Based on rainfall data and other characteristics of the basin, the average annual yield of the Upper Bhima River basin has been assessed as . Since the Bhima River which is a major tributary of the Krishna River is an interstate river, the flows are shared by the Upper riparian state of Maharashtra with the lower riparian Karnataka state. The Krishna Water Disputes Tribunal, in its award in the year 1976 permitted Maharashtra to use only from the Upper Bhima River Basin. The Bhima or Ujjani dam has planned annual utilization of (including evaporation losses).Features
The Ujjani Dam commissioned in June 1980 is an earth cum concrete masonry dam, which has created a multipurpose reservoir. The total length of the dam is , which comprises a central portion which is the spillway dam of length, of concrete gravity section of (maximum height above the deepest foundation level). The spillway is flanked by Non Overflow (NOF) concrete gravity dams of length. Earth dam sections flank the NOF dams on the left and right banks. The volume content of the dams is . The gross storage capacity created is at the Full Reservoir Level (FRL) of . The spillway, structure has an Ogee shaped downstream slope designed to dispose a design flood discharge of (the maximum probable flood discharge of and a breaching section is provided between the NOF block and the earth dam section, controlled by 41 radial gates of x size erected over the crest of the dam. In addition, four river sluices (gate controlled) are also provided in the body of the spillway pier numbers 3, 4, 5 and 6 with outlet level at , with each sluice designed for a discharge capacity of for silt flushing. The energy dissipation arrangements on the downstream slope of the spillway is in the form of high level and low level slotted roller bucket type. Measuring instruments have been installed in the body of the dam to record and analyse various parameters related to the behaviour of the dam over the years as part of the dam safety programme The dam is founded on massive basaltic rock formations.Reservoir
The reservoir created by the dam has a water spread area of at the High Flood Level (HFL) and at Full Reservoir Level causing submergence of land and houses in 82 villages. The reservoir stretches upstream of the dam to a length of around 50 km, and the maximum width of the reservoir is . The rim of the reservoir periphery measures . As a result of reservoir submergence, realignment of railway line (of the Daund Solapur section) to a length of , realignment of National Highway No. 9 between Pune and Solapur sector over a length of , and the State Highway between Tembhurni andBenefits
The Ujjani Dam and its large reservoir provide multi-purpose benefits of irrigation,Irrigation
Irrigation from the storage created in the reservoir are provided via two irrigation canal systems originating from the dam – The Left Bank Main Canal (LBMC) and The Right Bank Main canal (RBMC) – the LBMC is long, designed to carry a discharge of and provides irrigation to a command of while the RBMC, which is long, designed to carry provides irrigation benefits to an area of through its network of canal system. Bhima to Sina interlink (Jod Kalava) with 21 km long tunnel from Ujjani reservoir is constructed to supply water for vast lands in catchment area of Sina tributary. The storage created by the Ujjani Dam has resulted in the irrigation of , particularly in Solapur district, resulting in doubling the yield ofHydropower
A pumped storage type powerhouse has been built at the toe of the dam with an installed capacity of 12 MW (one unit of vertical Francis-reversible pump turbine) on the left bank of the dam, downstream from the axis of the dam. It operates below 20 percent load factor under a range of maximum head of and minimum head of . The hydropower component involved construction of a high weir, below the Ujjani Dam to control the lower pond for operation during the pumping mode. A penstock pipe of diameter ( thick) and length embedded in the dam diverts the flow of from a gate controlled trash racks (15 panels) covered intake into the powerhouse. The lower pond in the pumped storage scheme of operation was built initially itself, soon after commissioning of the dam. The power plant is reported to be providing benefits since then. However, the power generation estimated initially at 105 GWh was expected to reduce to 21 GWh, as water was utilized for irrigation through the RBC and LBC canal systems. During the drought year 2015, the inflows into the reservoir were very meagre due to the failure of rains in the catchment area. However, nearly 36 tmcft dead storage water available in the reservoir could not be used for the dire needs. With minor external modifications to the exiting reversible hydro turbine unit, all the dead storage water can be put to use during the drought years by using the hydro power plant for pumping water into the nearby left canal. Water would be released downstream into the tail pond through the existing river sluice gates. The pen stock of the hydro power unit is extended (less than 100 m long) to connect to the nearby left canal. The hydro power unit is operated in pumping mode to pump water from the tail pond to the left canal when the reservoir level is below the canal's minimum draw down level (MDDL). The pen stock extension piping is detached when water pumping to the canal is not required to restore its normal power generation when the reservoir level is above the left canal's MDDLOther benefits
The high density of phytoplankton (of many species) in the Ujjani Reservoir is conducive to proliferation of fish species. Production of fish resources from the reservoir has been estimated at 712 tonnes per year, and 19 percent of the catch consists species of major carps. Fish yield is reported to be 2450 kg/km2 of the water spread area of the reservoir.Bird watching
With the water reservoir of Ujani Dam, Bhigwan is a small town developed on the Pune-Solapur Highway around 105 km from Pune which is on the backwaters of Ujani dam. Bhigwan is famous for birdwatching especially flamingos and wild life photography. It is also known as mini Bharatpur. Many kinds of Ducks, Herons, Egrets, Raptors and Waders along with flocks of hundreds of flamingos can be seen. Variety of birds at Bhigwan gives of sighting of almost all the prime bird species there and also creates great photographic opportunities for wildlife photographers. At times, 1,000-1,200 flamingos are seen. The low rains and low water level has now reduced the number of flamingos over some years. It is a favorite spot for migratory birds, with more than 230 species found here. One can see flamingos, painted storks, bar-headed geese, demoiselle cranes, etc. These birds can be seen in the winter season between December and March. The bird generally migrates via marine routes and adult females depart from the breeding grounds .See also
* List of dams and reservoirs in Maharashtra * List of dams and reservoirs in India * Krishna Water Disputes TribunalReferences
{{Authority control Dams completed in 1980 Energy infrastructure completed in 1980 Dams in Pune district Hydroelectric power stations in Maharashtra Pumped-storage hydroelectric power stations in India Dams on the Krishna River Masonry dams 1980 establishments in Maharashtra