Spatial and Temporal Variation of the Hydrological Parameters in the Wouri-Nkam Section of the Cameroon Estuary, Central African Atlantic Coast

Felix Besack,Onguene Raphael,Edikin Roland Dieudonné,Tomedi Eyango Minette,Mbang Essome Junior,Ajonina Gordon Nwutih,Ebonji Seth Rodrigue,Nguekeu Brice,Sone Essoh Willy,Hamadou Toume Michel-Remi

doi:10.4236/ojms.2021.114009

Abstract

This study aimed to provide relevant knowledge about the dynamics of the hydrological parameters in the river-estuary continuum of the Wouri-Nkam river estuary for a sustainable management program. The hydrological parameters were recorded in eleven stations spanned out on the basis of population density and human activities. Water quality parameters (Temperature, salinity, dissolved oxygen, pH, Total dissolved solutes, Redox potential and conductivity) were collected in subsurface water using a multiple parameter. Surface currents and morphometric (depth and width) parameters were recorded using a drifter, sonar depth and GPS. The field measurements took placed between 18/05/2019 to 08/09/2020 and were divided into six (06) cruises. The data were later subjected to an analysis of variance (ANOVA) and Principle Component Analysis using XLSTAT 2017 (2.7 version) software. Results obtained revealed that, the water quality parameters were spatially more stable notsignficant at (df = 9, p 0.05) with a relatively low temperature (25.5°C - 27°C) during the wet period. The limit of the frontal zone extended to S5 (Bonalokan, 8.25 km from S1) during the snapshot of the dry period, spring phase and flood tide conditions. Inversely, during wet period, this extension reduced to S1 (Bridge) and relatively increases slightly to S3 (Bonangang) during the neap phase and ebb tides of this season. This result revealed a change in the axial gradient of about eight (08) and four (04) kilometers during the seasonal and tidal scales (lunar and diurnal periods) respectively. These changes were also accompanied by changes in the water quality signatures, that may affect the fishery distribution and compositions. However, futures studies to buttress the results of this investigation should focus on longer time series sampling methods and model developments.

Highlights

Rivers and estuarine systems around the world have attracted large numbers of people and are today affected by changes in land use, hydrological and biogeochemical cycles mainly driven by the continuous increase in population [1]
This paper focus on the understanding of the hydrological parameters dynamics in the Wouri-Nkam channel of the Cameroon estuary i.e., between the Oligohaline (Bridge) and the Limnic ends (Bona’Anja) from daily to seasonal time scales passing through the lunar cycle
Tidal variability of monitored water quality parameters Secondly, we examined the spatial evolution of the water quality parameters in the channel at different lunar phases (Figure 3)

Summary

Introduction

Rivers and estuarine systems around the world have attracted large numbers of people and are today affected by changes in land use, hydrological and biogeochemical cycles mainly driven by the continuous increase in population [1]. Some studies have shown that, human induced changes in salinity affect aquatic ecosystems and the marine species that dwell within them [4]. In this sense [5] have highlight that, joint changes in salinity and temperature yield a stronger indicator of human impact on climate change than either salinity or temperature alone. These numerous revelations have continuously increased the need for understanding the functioning of estuaries and their relation with the coastal environment

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Conclusion