Assessment of Temporal Variation of Water Quality Parameters and the Trophic State Index in a Subtropical Water Reservoir of Bangladesh

Abstract

This study was conducted to determine the suitability of water quality for fisheries management in Kaptai Lake from February 2019 to January 2020. Results showed that the temperature, transparency, TDS, pH, DO, EC, alkalinity and hardness were 20.9 to 31.8°C, 17 to 303 cm, 40 to 105 mg/L, 6.82 to 7.96, 6.1 to 7.65 mg/L, 75.33 to 172.33 µS/cm, 37 to 83 mg/L and 35 to 190 mg/L, respectively. However, nutrients as NH3, NO3-, NO2-, PO43- and SO42- were 0.01 to 0.05, 0.03 to 2.21, 36 to 96, 0.01 to 0.04 and 0.3 to 1.9 mg/L, respectively. Chlorophyll a and trophic state index (TSI) were 0.70 to 2.12 µg/L and 27.43 to 37.79, respectively. Study revealed that SO42-, DO and TDS were higher than the standard of ECR. On the other hand, NH3, NO3-, NO2-, PO43-, temperature, transparency, pH, EC, total hardness, total alkalinity, Chlorophyll a and TSI were within the standard levels. Concentrations of NO3-, NO2-, PO43-, Chlorophyll a and TSI (CHL) showed no significant variation with seasons. Conversely, TDS, transparency, EC, alkalinity, hardness, and SO42- were lower in monsoon compared to pre-monsoon and post-monsoon seasons. Besides, temperature, NH3, DO and TSI (SD) were higher in monsoon season. Results concluded that the Kaptai Lake is in mesotrophic condition with TSI (CHL) less than 40, and prominently there was a positive relationship between Chlorophyll a and Trophic State Index (TSI). In this regard, major nutrients and Chlorophyll a concentration in the Kaptai Lake may have an impact on the aquatic environment.

Assessment of the Seasonal Variations of Lakes Water Quality in Bangladesh

“…The higher EC is attributed to the high degree of anthropogenic activities such as waste disposal and runoff. The St-1 and St-5 showed the highest and lowest TDS content in both seasons, respectively where TDS content was higher in post-monsoon than monsoon that supported by [23]. and the CV showed positive relationship between variables.…”

Effect of environmental drivers of fish assemblage and diversity patterns in temporal scale in Mongra Reservoir: A case study from one of the tributaries of Mahanadi Basin, Central India

“…The runoff from the attachment area contributed a lot of dissolved solids (Kumari et al, 2019). Transparency was recorded maximum in 1.85 ± 0.33 m in the pre‐monsoon season and 1.1 ± 0.5 m the monsoon season, which indicates the rapid increase in suspended matter (silt, clay and organic matter) and sediment from the catchment areas during the monsoon season resulting in rise in turbidity (Halder et al, 1990; Islam et al, 2021), and high values occurred during summer due to lack of rain, runoff and flood water as well as gradual settling of suspended particles (Saxena & Saksena, 2012). Rahman (1992) suggested that productive water bodies have a transparency of no more than 0.4 m. similar seasonal trends were found in the Tono reservoir (Akongyuure & Alhassan, 2021), Raipur reservoir (Saxena & Saksena, 2012) and Sardar Sarovar reservoir (Koushlesh et al, 2022).…”

“…in rise in turbidity (Halder et al, 1990;Islam et al, 2021), and high values occurred during summer due to lack of rain, runoff and flood water as well as gradual settling of suspended particles (Saxena & Saksena, 2012). Rahman (1992) suggested that productive water bodies have a transparency of no more than 0.4 m. similar seasonal trends were found in the Tono reservoir (Akongyuure & Alhassan, 2021), Raipur reservoir (Saxena & Saksena, 2012) and Sardar Sarovar reservoir (Koushlesh et al, 2022).…”