Switching of the water in a principa1 cana1 to a secondary one for irrigation of the fields. - - Technical Assistance to the Upper and Middle Sao Francisco Irrigation Project: FAO/UTF/BRA/026/BRA. The Sao Francisco Va11ey is located in the north-east part of Brazi1 and occupies an area of 64 mi11ion ha. Its agricu1tura1 potentia1 has been estimated at 3 million ha. of irrigable land and 27.3 million ha. for dry1and crops. The region has potentia1 energy of 13.7 mi11ion Kw. The UN Food and Agricu1ture Organization (FAO) is providing technica1 assistance to CODEVASF - Companhia de Desenvo1vimento do Vale do Sao Francisco - in agricu1tura1 deve1opment, deve1opment p1anning and water resource economics. It is a1so providing expert services in hydrau1ic works, geotechnics, design, operation and maintenance of irrigation and drainage networks and pumping stations.