The Western Ghats have several manmade lakes and reservoirs. The well known lakes are the Ooty (2500 m altitude, 34.0 ha) in Nilgiris, and the Kodaikanal (2285 m, 26 ha) and the Berijam in the Palani Hills. The Pookode lake of Wayanad in Kerala at Lakkadi is a beautiful scenic one with boating and garden arrangements. Most of the bigger lakes are situated in the state of Tamil Nadu. Two smaller lakes, Devikulam (6.0 ha) and Letchmi (2.0 ha) are in the Munnar range.
The majority of streams draining the Western Ghats that join the rivers Krishna and Kaveri carry water during monsoon months only and have been dammed for hydroelectric and irrigation purposes. The major reservoirs are: Lonavala and Walwahn in Maharashtra; V.V. Sagar, K.R. Sagar, Bhadra, Lingamakki in Karnataka; Mettur, Upper Bhavani, Lower Bhavani, Mukurthi, Parson’s Valley, Porthumund, Avalanche, Emerald, Pykara, Sandynulla, Karaiyar, Servalar, Kodaiyar, Gadananathi River, Manimuthar and Glenmorgan in Tamil Nadu; and Kundallay and Maddupatty in Kerala. Of these the Lonavla, Walwahn, Upper Bhavani, Mukurthi, Parson’s Valley, Porthumund, Avalanche, Emerald, Pykara, Sandynulla, Glenmorgan, Kundally and Madupatty are important for their commercial and sport fisheries for rainbow trout (introduced), mahseer (native) and common carp (introduced).[17]
The Western Ghats form one of the four watersheds of India, feeding the perennial rivers of India. Important rivers include the Godavari,[18]Tungabhadra, Krishna, Thamiraparani and Kaveri. These rivers flow to the east and drain out into the Bay of Bengal. The west flowing rivers, that drain into the Arabian Sea and the Laccadive Sea, are fast-moving, owing to the short distance travelled and steeper gradient. Important rivers include the Periyar, Bharathappuzha, Netravati, Sharavathi, Mandovi and Zuari. Many of these rivers feed the backwaters of Kerala and Maharashtra. Rivers that flow eastwards of the Ghats drain into the Bay of Bengal. These are comparatively slower moving and eventually merge into larger rivers such as the Kaveri and Krishna. The larger tributaries include the Tunga River, Bhadra river, Bhima River, Malaprabha River, Ghataprabha River, Hemavathi river, Kabini River. In addition there are several smaller rivers such as the Chittar River, Gadananathi River, Manimuthar River, Kallayi River, Kundali River and the Pachaiyar River.
Fast running rivers and steep slopes have provided sites for many large hydro-electric projects. There are about 50 major dams along the length of the Western Ghats with the earliest project up in 1900 near Khopoli in Maharashtra.[19] Most notable of these projects are the Koyna Hydroelectric Project in Maharashtra, the Parambikulam Dam in Kerala, and the Linganmakki Dam in Karnataka.[12] The reservoir behind the Koyna Dam, the Shivajisagar Lake, has a length of 50 km (31 mi) and depth of 80 m (262 ft).[20] It is the largest hydroelectric project in Maharashtra, generating 1,920 MW of electric power.[21] Another major hydro electric project is Idukki dam in Kerala.
During the monsoon season, numerous streams fed by incessant rain drain off the mountain sides leading to numerous and often spectacular waterfalls. Among the most well known is the Jog Falls, Kunchikal Falls, Dudhsagar Falls, Sivasamudram Falls, and Unchalli Falls. The Jog Falls is the highest natural plunge waterfall in South Asia and is listed among the 1001 natural wonders of the world.[22] Talakaveri wildlife sanctuary is a critical watershed and the source of the river Kaveri. This region has dense evergreen and semi-evergreen vegetation, with shola-grassland in areas of higher elevation. The steep terrain of the area has resulted in scenic waterfalls along its many mountain streams. Sharavathi and Someshvara Wildlife sanctuaries in Shimoga district are the source of the Tungabhadra River system. The Netravathi river has also its origin at Western Ghats of India flowing westwards to join Arabian sea at Mangalore.