and the Palni Hills in Dindigul District form the Aanaimalai Conservation Area. The Steering Committee of Project Tiger granted approval in principle to inclusion of Indira Gandhi WLS and NP under Project Tiger in 2005. IGWS was declared a Project Tiger sanctuary in 2008. Continuance of 'Project Tiger' in Anamalai Tiger Reserve for FY 2010/11, at the cost of 23,547,000 was approved by the National Tiger Conservation Authority on 31 August 2010. This tiger reserve, together with the several other contiguous protected forest and grassland habitats, is the core of the Parambikulum-Indira Gandhi tiger habitat landscape complex, with tiger occupancy area of about and an estimated metapopulation of 42 tigers. Geography Mean annual rainfall is between in the south western fringes and on the north east. This Sanctuary is an important watershed for the agricultural economy and power supply in other parts of Tamil Nadu. Major reservoirs like Parambikulam Reservoir, Aliyar Reservoir, Thirumurthi Reservoir, Upper Aliyar Reservoir, Kadambarai, Sholayar Dam and Amaravathi Dam are fed by the perennial rivers which originate from the Sanctuary. The sanctuary has six administrative ranges; Pollachi: a southern suburban town of Coimbatore, its range headquarters at Anaimalai Farm: Valparai Water Falls: Ulandy Top Slip: Amaravathi Reservoir: Amaravathi Nagar: Udumalpet: . IGWLS is adjacent to Parambikulam Wildlife Sanctuary to the west. The core area of Manjampatti Valley is a with a drainage basin at the eastern end of the park. Manjampatti Valley is contiguous with Chinnar Wildlife Sanctuary to the south and the proposed Palani Hills Wildlife Sanctuary and National Park to the east. The National park enters Ernakulam district and Idukki district of Kerala (the Pooyamkutty forest), from the tribal settlement of Edamalakudy, Idukki. Elevation ranges between and . Flora The park is home to a wide variety of flora typical of the southern Western Ghats. There are over 2000 plant species, of which about 400 species are of prime medicinal value. The diverse topography and rainfall gradient allow a wide variety of vegetation comprising a mix of natural and human-made habitats. The former includes tropical and subtropical moist broadleaf forests and East Deccan dry evergreen forests, montane shola-grassland, tropical and subtropical dry broadleaf forest, Deccan thorn scrub forests and marshes. South Western Ghats montane rain forests occur at higher elevations and are interspersed with montane grasslands, forming the shola-grassland complex. Much of the original forest now contains introduced teak plantations. Bamboo stands and reed