Corumbatai River (Brazil)

Basin Overview

Within the Piracicaba, Capivari and Jundiaí river Water Resources Management Unit (UGRHI 5 – PCJ), the Corumbataí River is located in the central region of São Paulo State (Brazil), constituting none of the most important tributary of the Piracicaba River. The basin extends over about 1,700 km² distributed among 9 municipalities, representing source for water supply for more than 600,000 inhabitants, of which more than half reside outside the limits of the basin. Elevation ranges from 900 meters in the northern portion to 600 meters in lowland of the basin. Higher zones are occupied by outcrops of sandstones related to Guarani Aquifer System, representing an important recharge zone for this aquifer. The middle and lower portion of the basin are occupied by glacial and fluvial deposits associated to the Tubarão Aquifer System, as well as mudstones from the Aquiclude Passa Dois.

 

Facts and Figures

Country:  Brazil
State: São Paulo
Major Population Centers (people in 2017): Rio Claro (186,253) and Piracicaba (364,571)

River Length: 66 km
Watershed Area: 1,679 km2
Köppen Climate Classification: dry-winter (April to September) subtropical

Source: Guarani and Tubarao aquifers
Mean annual precipitation: — cm/yr

Mouth: Piracicaba river
Mean annual precipitation: 14.6 cm/yr
Mean annual discharge at mouth: 144 m3/s

People and Land Use

Major land use in the basin is related to agriculture, that represents 79% of the total area. Only 17% of the total area is occupied by forested areas and 4% by urban zones. The main agricultural product is sugar cane, that represent the most important economic activity in the basin followed by mining activity to supply the ceramic pole located in Santa Gertrudes.

Major Issues

Demand for water resources to supply urban areas is more than 95% of the total water extracted from the Corumbataí river. The volume extracted surplus the total water availability (less than 1,500 m3.hab-1.year-1) and the tendency for the future is an increase in water demand to support the economic development of the basin. This increase in water demand tends to be supported by groundwater, and wells have been drilled to supply water for private users, without a knowledge about groundwater availability in the basin and specific management policies. Another issue is related to the protection of the Guarani Aquifer System recharge areas against pollution sources associated to agricultural practices and impacts related to climate changes, since recent intense droughts have impacted negatively in water availability.

Research Questions:

  • How does recent and past industrial development and urbanization processes impact on the urban hydrological cycle? Can these impacts be tracked using stable isotopes or different environmental tracers?
  • What is the extent of the recent uncontrolled increase in groundwater extraction in the watershed on water availability? Establishment of groundwater conceptual models using multiple tracers (geochemical evolution and dating tracers)
  • What is the spatial-temporal variability of isotopic composition of rainfall (high spatial and temporal sampling procedures)

Skillset: Physical hydrology, isotopes, geospatial analyses.