Assessment of physico-chemical parameters of freshwater in the Sidi Abderrahmane reservoir, Safi, Morocco

• Published in: African journal of aquatic science Vol. 45; no. 3; pp. 259 - 268
• Main Authors: Belokda, W, Damsiri, Z, Natij, L, Khalil, K, Loudiki, M, Dahbi, A, Achtak, H, Richir, J, Sabour, B, Elkalay, K
• Format: Journal Article Web Resource
• Language: English
• Published: Grahamstown Taylor & Francis 02-07-2020; Taylor & Francis Ltd
• Subjects: Ammonium; Ammonium compounds; Anoxia; Arid climates; Aridity; Autumn; Body temperature; Chlorophyll; Chlorophyll a; Dissolved oxygen; Electrical resistivity; Environmental sciences & ecology; Fertilizers; Freshwater; Homogeneity; Inflow; Inland water environment; Life sciences; Mineral nutrients; Nitrates; Nitrites; Nutrient concentrations; Nutrients; Orchards; Oum Er-Rabia Basin; Outflow; Oxygenation; Parameters; physicochemical; Quality assessment; Reservoirs; Residence time; Safi region; Sciences de l’environnement & écologie; Sciences du vivant; Semiarid climates; Stratification; Temperature; Transparency (optical); Water analysis; Water bodies; Water circulation; Water column; Water properties; Water quality; Water quality assessments; Water sampling; Water stratification; waterway; Wind effects; Morocco
• ISSN: 1608-5914; 1727-9364; 1727-9364
• DOI: 10.2989/16085914.2019.1692777

The purpose of the study was to assess the water quality in the Sidi Abderrahmane freshwater reservoir (Safi, Morocco). The monitoring data used in the study included physical, chemical, and biological characteristics. The spatial and temporal characteristics of these parameters was evaluated by collecting water samples fortnightly from May 2011 to December 2012 in three stations chosen to represent different parts of the reservoir. Ten parameters considered as indicators of water properties were analysed: temperature, dissolved oxygen, pH, electric conductivity, transparency, orthophosphorus, ammonium, nitrites, nitrates, and chlorophyll a. The results show that nutrient concentrations were among the highest (mean concentrations: PO
3−
= 0.64 mg l
−1
, NH
4+
= 1.08 mg l
−1
) recorded for Moroccan freshwater reservoirs. Our data indicated that the Sidi Abderrahmane is a destratified reservoir that it is relatively warm (mean temperature: 22.42 ± 4.88 °C); a polymictic reservoir in a semi-arid climate. Fertilisers applied in the surrounding orchards affect significantly affect nutrient levels in the waterbody, particularly PO
3−
and NH
4+
in autumn. The water column is seasonally homogeneous, as a result of wind-induced mixing, and our tests showed no anoxia throughout the study period. With suitable hydraulic conditions (short residence time, short outflow/inflow ratio, good oxygenation, and homogeneity), the Sidi Abderrahmane water body could reduce the stratification time and improve water quality.