The study area covers the São Francisco catchment of 641,000 km2 and with 13 million inhabitants it is one of the most important river basins in Brazil (Fig. 7). Much of the area is part of the so called “dry-polygon" of the country. The river is heavily used by dams, river drains and water abstractions. The area of the basin is characterized by intensive agriculture and mining activity, the latter mainly in the upper reaches. 75% of the water flow are generated in the upper reaches of the state of Minas Gerais. This area is relatively densely populated and mining provides long had a major economic factor, making Minas Gerais is characterized by extensive environmental impacts, loss of biodiversity and severe soil erosion. In particular, the high sediment mobility affects the approx. 50 hydropower plants in the river area, which in part has considerable consequences for the local water and electricity supply. So the Cachoeira Dourada -Stausee example, has already lost over the last 50 years, 40% of its storage volume. The sediment deposits ("sedimentation") are a serious problem in almost all dugouts, especially in the lower reaches of São Francisco, where climatic conditions are semi-arid and reservoirs are the most important basis for regional water and electricity supply. In a large, national initiative, the Brazilian Ministério da Integração Nacional (MI 2015) initiated the Basin Interlinking Project, which aims the water supply for 12 million people in the urban and rural areas of the states of Ceará, Rio Grande do Norte, Paraíba and improve Pernambuco by transitions from the Sao Francisco in the local river systems. These areas north of the actual catchment area are connected by a 402km-long northern transition and a 220km long eastern transition. In this way, the river basin of the São Francisco expanded into a larger hydrological system "Extended" São Francisco River Basin.
The proposed here investigation projects in the extended São Francisco River Basin is very promising because it combines the following criteria perfectly:
The São Francisco River Basin extends to a large part in a semi-arid area where about 15 million people are heavily dependent on its water resources. Therefore, the river water use is under a great pressure of demand, both because of the limited natural water availability, as well due to an increase (due to a wide variety of reasons) water demand in recent years.
The São Francisco River Basin is highly complex because different water users compete to affect uses the upper and lower reaches strongly against each other and cause interrelated reservoirs or newly created flow transitions to adjacent basins that are even lower water content than the São Francisco- Territory.
This project was financed by the German Federal Ministry of Education and Research under the financial assistance agreement No 02WGR1421.