Avaliação da influência das descargas fluviais na distribuição da salinidade no estuário Bons Sinais - Zambézia

Abstract

The river discharge is responsible for the entry of fresh water into the estuary, since the discharges depend mostly on rainfall, which is conditioned by the seasons of the year. which governs the distribution of salt and primarily regulates the extent of saline intrusion. in studies made in the estuary of the good signs were limited to describing the scope of the saline intrusion without observance of seasonality. This aspect raises the question of the reach of salt during the year. For to answer this question, 7 campaigns were carried out along the Bons Sinais estuary 11 stations including the rivers Cuacua 5 seasons and Licuari 6 seasons in the months of April 2019 (rainy season), July 2018 (intermediate season), September (2017 and 2019) and November (2017) (Dry season), through of profiles using CTD a topography using a probe. Results indicate the incursion of salt in an extension of 20 km to 40 km along the Bons Sinais estuary when the river flow is 811 m 3/s and 777 m3/s fact recorded in the rainy season, the In the intermediate season the distribution reaches more 60km on the Cuacua River, while in the dry season the incursion of salt reaches more than 60 km. The level of salinity varying from 8,006 PUS to 22.8 PSU, 29.17 PSU to 33.52 PSU and 0.043 to 7.85, at the times intermediate, dry and rainy areas of the Cuacua and Licuari rivers, respectively. whereas at the time rainy season the average salinity level in the mouth is 14.70psu and saline wedge ends at 19.64 km this at 782 m before station 5 (in the region of Porto de Quelimane). These results lead us to conclude that the distribution of salt in the estuary increases by 30 km and 40 km in the intermediate seasons and dry, respectively.