The control of a small dam in nutrient inputs to an hypertrophic estuary.
2007
Avilés-Benítez, Antonio | Niell, F Xavier
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 dammed water 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) reaching during the dry season values of 55 %. Total nitrogen (TN) showed higher seasonal variability than TP, ranging between a removal of 79.8 % and an increase of 41.2 %. Palmones River exported 11.3 TonsP y-1 of TP and 72.1 TonsN y-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 three months with important flooding events, the percentage of total nitrogen exported reached 64.5 %.
显示更多 [+] 显示较少 [-]This research was supported by the projects AMB99-1088 and REN2002-00340/MAR of the Spanish Commission of Science and Technology Inter-Ministry. We wish to thank the Agencia Andaluza del Agua and mainly, German Ríos for providing data on river flow and water quality. We are also grateful to the Consejería de Medioambiente de Cádiz for providing data on sewage inputs. Thanks also to Eduardo Briones for his help on the sampling trips.
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