Valuation of Atlantic Forest environmental services in the water quality and quantity of the Sana EPR. / Valoração dos serviços ambientais da Floresta de Mata Atlântica associados à qualidade e quantidade da água na APA do Sana.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The study evaluated the relationship between soil coverage and the quality and quantity of water in watersheds in order to assess the environmental services of the Atlantic Forest in two micro basins. The micro basins Palmital and Glória are located in the Sana Environmental Protection Area (EPR), municipality of Macaé (RJ). They are covered by different percentage of Atlantic Forest and pasture, and the water is used for public supply without any physical or chemical treatment. Environment properties of the micro basins were surveyed, and the water quality monitored monthly for one year, and thereafter daily for another year. The water flow and precipitation were measured daily for one year, through devices installed in the microbasins. The sediment loss was measured locally and the soil loss was estimated by the Universal Soil Loss Equation (USLE). The environmental services of the Atlantic Forest in the water production were valuated based on the users potential to pay for these services. The cost of water treatment was used to evaluate the cost for suppliers of environmental services, and to compare the services provided by the Atlantic Forest in terms of the water quality. The environment diagnosis of Palmital micro basin showed that most of the area is covered by well preserved Atlantic Forest (61.58%). Comparison of divergences between the recommended and the actual land usage showed that pasture was the biggest disparity in the Glória micro basin (44% of the EPR). The monthly monitoring of the water quality did not show difference between the micro basins. The hydrological pattern was similar between the micro basins; however the Palmital, with largest area covered by Atlantic Forest (61.58%), presented a water flow higher than the Gloria micro basin (51.06% of the area with pasture). The total solids in the water of the two microbasins was low, and the values were within the allowed limit for water Class I (300 mg L-1). The turbidity of Palmital water was below the limit required for Class I potable water (5 NTU). In the Gloria micro basin, the turbidity values were above that limit in four months of the year. The sediment production measured directly showed values close to the soil loss estimated by the USLE (10 t ha-1 year-1). The environment valuation, based on the cost of water treatment, showed that the Palmital micro basin was able to maintain good water quality, without physical or chemical treatment for its usage; while in the Gloria micro basin the water treatment was necessary for its consumption. In the Glória micro basin, the cost of reforestation of the pasture plus the opportunity cost of water service providers, considering the willingness of local users to pay for the environment services, was cheaper than the cost of water treatment. The valuation of the environmental services of the Sana EPR, through users contribution, would allow the reforestation of the riparian area of Sana River in a period of about 2.2 years.

ASSUNTO(S)

water quality indicators engenharia agricola forest microbasins microbacias florestais. indicadores de qualidade de água manejo de bacias watershed management

ACESSO AO ARTIGO

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