Implementation challenges of water and land-use plans: a case study on the Guarani aquifer system in Sao Paulo, Brazil

The Guarani Aquifer System (GAS) is considered to be a strategic fresh water reserve in Latin America, occurring in regions of Brazil, Uruguay, Argentina and Paraguay. The east and west zones of the GAS are unconfined and, consequently, more vulnerable to contamination. A lack of adequate planning and management is leading to problems of contamination and intensive exploitation of water. This paper presents findings of a comprehensive study conducted in the unconfined zone of the GAS in the Sao Paulo State (Brazil), which resulted in the Development and Environmental Protection Plan for the GAS (DEPP-GAS) and the Protection and Recovering Area for the GAS (PRA-GAS), both management instruments of the state Act 9866/97. This paper aims to highlight key implementation challenges of the DEPP-GAS and provide recommendations to overcome them. The study utilized the GOD method (groundwater occurrence; overall characteristics of the aquifer; and depth of water) and POSH method (pollutant origin; and surcharge hydraulically) for mapping the groundwater vulnerability to contamination and the potential sources of groundwater contamination. The overlap of these maps generated the hazard of groundwater contamination. The study proposed the first protection and recovering area created for an aquifer. Preliminary findings of this investigation indicate challenges for implementing the proposed DEPP-GAS, since the area has 26,110 km2, several towns and agro-industrial centres, and covers the territory of 105 municipalities and 7 Water Resources Management Units (WRMU). The main challenge of this plan will be articulating the actions which take place at the regional level with local actions. This study also remarks that for an effective protection of the aquifer, other portions of the GAS in Brazil and in other countries should be focus of future researches.