section in river Krishna in Vijayawada on the right side upstream off Prakasam barrage through a head sluice at Seethanagaram and joins the Buckingham canal at Peddaganjam Lock near Ongole. The Buckingham canal is a tidal canal stretching from Peddaganjam lock to Chennai and further down south up to Marakkanam. The stretch of the canal from Peddaganjam lock to Chennai for a length of is called "North Buckingham canal" and the canal path from Chennai to Marakkanam for a total length of is called "South Buckingham canal". It was constructed during the 19th century along the Coromandal Coast. Marakkanam is connected to the Sea (Bay of Bengal) at Pondicherry by the Kalluvelly tank. The lengths of the NW-4 in Andhra Pradesh, Tamil Nadu, and Puducherry are as follows: Geographical boundaries Development The concept of National Waterways was introduced in 1982 to promote the development of inland water transport in the country. At present, out of six declared National Waterways, developmental works are being carried out on NW-1, 2, and 3 only by Inland Waterways Authority of India (IWAI). The first three National Waterways (NW-1, 2 & 3) are being developed for shipping and navigation by providing basic inland transport infrastructural facilities, including navigational channel with required depth and width, aids for day and night navigation, and terminals at selected locations for berthing and loading/unloading of vessels. In NW-1 & 2, IWAI undertakes river conservatory works to provide navigational channel of , , and depth in different stretches during the low water period. In NW–3, IWAI is carrying out dredging to provide a navigational depth and width of and , respectively. Development works are being carried out with the objective of making all three National waterways fully operational with cargo and other inland vessels by March 2012. For National Waterways 4 and 5, IWAI initiated the proposals for development in July 2010. Techno-economic studies for establishment of National Waterways NW-4 was done by Water And Power Consultancy Services (WAPCOS), a subsidiary of Ministry of Water Resources The completion period for NW-4 was estimated at seven years by Detailed Project Report prepared by WAPCOS, which is contrary to that of 2002 estimates which indicated five years as completion period. of land are required for NW-4 construction; , , and land has to be acquired in the states of Tamil Nadu, Andhra Pradesh, and Puducherry respectively. Traffic A. F. Ferguson was appointed by