Act, 1971. On 26 January 1972, the district of Idukki was formed by the separation of the three High Range Taluks, namely Devikulam, Udumbanchola, and Peerumede, from Kottayam district. The High Range region was merged with the Thodupuzha taluk of Ernakulam district to form the district of Idukki. It was the largest district of Kerala by area at that time. In 1998, Kuttampuzha village was transferred into the Ernakulam district, making Idukki the second largest district in Kerala, only after to Palakkad. The High Range region is still sparsely populated and various cash crops and spices are extensively cultivated there. Now various hydroelectric power projects in the district of Idukki contributes around 66% of the total power needs of Kerala. The Mullaperiyar Dam still remains as the source of the interstate dispute between Kerala and Tamil Nadu. Geography The Idukki district forms a high altitude plateau with rugged mountainous terrain, several river valleys and deep gorges. The entire northern part of the district forms a sub plateau higher than the rest of the district, this region includes the tallest peaks like Anamudi and includes the areas around Munnar, Pallivasal, Kanthalloor, Vattavada and Mankulam. The Pambar river valley (Marayoor, Keezhanthoor) forms an eastern sloping rain shadow region of the Western Ghats. The eastern frontier of the district (Kumily, Kattapana, Nedumkandam, Rajakumari and Ramakkalmedu) constitutes the Cardamon hills. The western part of the district is covered by forests and hills bordering the eastern regions of Ernakulam and Kottayam district like Neriyamangalam, Vannapuram, Thommankuthu, Moolamattom, Vagamon and Kuttikanam. Places like Thodupuzha, Koothattukulam, Udumbanoor and Muttom are situated in the semi elevated Thodupuzha river plains with scattered hills. The Periyar river basin in the district which includes Vandiperiyar, Ayyapankoil, Rajakkad, Idukki, Cheruthoni and Adimaly is an elevated plateau crisscrossed by river valleys and lies between the high peaks of the western and eastern parts of the district. The southern region is entirely covered with the forests of the Periyar National Park. Anamudi and Meesapulimala, the two highest peaks in India south of the Himalayas, are located in Idukki district. Anamudi is situated in the Kuttampuzha Panchayat of Adimali Block in the Kannan Devan Hills village of Devikulam taluk. Thirteen other peaks in the district exceed a height of . Periyar, Thodupuzhayar, Muthirappuzhayar, and Thalayar are the important rivers of the district. Idukki Dam, Asia's largest arch dam, is located in the Idukki Township. The