The whole of the Maduru Oya basin and a portion of the Mahaweli basin are covered by the system. The supplies of water to these lands are by Maduru Oya reservoirs. Left and Right bank canals supplies the entire water requirement. The Maduru Oya reservoir in addition to regulating the yield from its catchment will be augmented by the right bank trans-basin canal. The general topography of the area is flat with maximum slopes of 2%. (in 1968 report)
The Maduru Oya project, a component of the Mahaweli Development Scheme, is located in the basin of the Maduru Oya, which lies to the east and is separate from that of the Mahaweli Ganga itself. The first major project taken up for construction under the Accelerated Programme of Mahaweli Development was the Maduru Oya Project.
Construction work was ceremonially inaugurated on this Project by President Jayawardana on August 14, 1978.
The Maduru Oya has its source in the Uva hills east of Bibile at an elevation of 274 m. (900 ft.) above sea level. It flows north-eastwards covering a distance of about 136 km. (80 mls.) and disgorges into the Vandaloos bay near Kalkudah on the east coast.
Apart from the Northern plains, the flat littoral to the east of the Mahaweli, drained by the Maduru Oya and other streams rising in the Uva hills received the attention of our tank building kings. This is attested to by major works lying in disuse on the Maduru Oya basin itself.
The Maduru Oya basin, now in thick jungle, adjoins the Mahaweli basin on the eastern side and has an area of 453 sq. kms. (175 sq.miles). The Maduru Oya project envisage the construction of a 40 metre (131 ft) high and 1080 metre (3280 ft.) long rockfill dam across the Maduru Oya to create a reservoir of 467 million cubic metres (379,000 ac.ft.) capacity. The reservoir will be augmented by Mahaweli flows diverted from the now Minipe anicut. Three 2.4 MW turbines will be installed at the sluices for generation of hydro-power, at a later date.
The purpose of the project is to provide irrigation water to the System B area, so as to facilitate the ultimate settlement of some 35,000 farming families.
The total area of System B is approximately 135,000 ha. The present population is 26,000.
The climate is typical of the “Dry zone” of Sri Lanka, with 75 percent of average annual rainfall occurring in the Maha season.
