The original plan of the project involved the construction of a 101.2 kilometres (62.9 mi) long aqueduct that diverts water from the Rio Colca close to Tuti and transfers it around Ampato mountain to a canal which ends into the Siguas River.
[4] From the Siguas River a 15.7 kilometres (9.8 mi) long tunnel-canal starting at Pitay delivers the water to the Pampa de Majes.
[5] As part of Majes-Siguas II, another diversion at Lluclla can divert as much as 23 cubic metres per second (810 cu ft/s) in a 15.95 kilometres (9.91 mi) long canal to the Pampa de Siguas.
[5] The irrigated area has been planted with artichokes, avocado, cantaloupe, chili pepper, cochineal, garlic, grapes, kiwicha, onion, paprika, peas, quinoa and tomatoes;[9] also there is a dairy industry at Majes-Siguas.
[22] In November 2018, a commission of the Congress of Peru started investigating events surrounding Majes-Siguas II, including the delay but especially the decision by the Governor of Arequipa Region to modify the construction contract which raised the price of the project and the exact nature of this modification,[23] which involved using pipelines[24] instead of canals at a price exceeding US$100,000,000.
This change known as "Addendum 13" had been proposed after the project had met resistance by the people of Espinar Province which were afraid that the Angostura Dam would impact their own agricultural development.