『Abstract
　A two-year study was carried out in the lower part of the Palmones River to describe the role of a small dam controlling the nutrient fluxes to the estuary. Results showed an important spatial heterogeneity in the nutrient content and water properties of lowland catchment due to the effects of the small dam and the effluents of a sewage treatment work. Taking into account the values of hydraulic retention time, the dam could be considered as an optimally dimensioned pre-dam. Therefore, it removed on average more than 25％ of total phosphorus (TP) while no net removal was obtained for TN during the studied period. Palmones River exported 11.3 Tons P year^-1 of TP and 72.1 Tons N year^-1 of TN to the estuary showing important seasonal differences. Less than 10％ from the total amount of nutrient was exported during low flow conditions, while in four months with important flooding events, the percentage of total nitrogen exported exceeded 64％.

Keywords: eutrophication; municipal sewage; nutrient forms; Palmones River; pre-dam; self-depuration』

1. Introduction
2. Study area
　2.1. Palmones river
　2.2. Dammed water
　2.3. The Palmones estuary
3. Materials and methods
　3.1. Sample collection
　3.2. Sample processing and analytical procedures
　3.3. Statistical analyses
4. Results and discussion
　4.1. Water chemistry and nutrient concentrations
　4.2. The role of the dam in the removal of nutrients
　4.3. Nutrient export to the estuary
Acknowledgments
References