Kerala's western coastal belt is relatively flat compared to the eastern region,[1]: 33 and is criss-crossed by a network of interconnected brackish canals, lakes, estuaries,[19] and rivers known as the Kerala Backwaters.[20] Kuttanad, also known as The Rice Bowl of Kerala, has the lowest altitude in India, and is also one of the few places in world where cultivation takes place below sea level.[21][22] The country's longest lake Vembanad, dominates the backwaters; it lies between Alappuzha and Kochi and is about 200 km2 (77 sq mi) in area.[23] Around eight percent of India's waterways are found in Kerala.[24] Kerala's 44 rivers include the Periyar; 244 kilometres (152 mi), Bharathapuzha; 209 kilometres (130 mi), Pamba; 176 kilometres (109 mi), Chaliyar; 169 kilometres (105 mi), Kadalundipuzha; 130 kilometres (81 mi), Chalakudipuzha; 130 kilometres (81 mi), Valapattanam; 129 kilometres (80 mi) and the Achankovil River; 128 kilometres (80 mi).