Variations In Water Quality Parameters Research Articles

Shading solutions for sustainable water management: impact of colors and intensities on evaporation and water quality

This study investigated the effectiveness of suspended shade covers in reducing evaporation rates and improving evaporation suppression efficiency. The experiment tested different shading colors (black, white, and green) and intensities (50, 70, and 90%) while considering ecological and economical aspects. Evaporation was determined using class-A evaporation pans, and various microclimatic variables were measured below the shade covers. Additionally, water quality parameters such as EC, phosphate, nitrate, and chloride concentrations were monitored. The results showed that black covers had the highest evaporation suppression efficiency with values of 56.8, 53.6, and 51.7% observed under 90% shading intensity for the black, green, and white covers, respectively. Despite variations in water quality parameters which all met Jordanian and FAO standards for irrigation water, the economic feasibility of installing these covers was found to be viable due to the resulting benefits in water conservation and crop production. However, selecting the best shading cover should consider the multipurpose use of agricultural reservoirs, including aquaculture, and further studies are recommended to investigate other overlapping aspects on a reservoir scale.

Spatial and temporal distribution of physicochemical parameters of water in Gorgan Bay (the southeast of the Caspian Sea - Iran): Fundamentals for the monitoring of the Caspian Sea coastal areas

Gorgan Bay as a main part of the Miankaleh (a natural biosphere reserve registered by UNESCO) is one of the richest ecological area in the West Asia and very important internationally recognized refuge for the wildlife. To date, multi physicochemical parameters have not been examined on a large scale. To fill this knowledge gap, the present study aimed to explore the seasonal and spatial variability of water quality parameters of the bay. The results showed that except for depth and transparency, there are significant variations in most parameters across the four seasons. The patterns of these changes in the bay vary, as evidenced by a comparison of the distribution maps of the various factors throughout the year. Notably, alkalinity declined from east to west, reaching its highest levels at important entry points such as the Qarasu River, Bandar-Gaz, and the pier. TDS, on the other hand, increased westward, reaching its highest concentration in the shallow western regions. Maximum depth (310 cm) and transparency (250 cm) were observed in the central bay. While the pH was higher in deeper areas, the distribution of PO4 was more uniform. With lower levels in the east (salinity = 0.40 ‰) and higher levels in the west (salinity = 28.9 ‰), the salinity showed a coherent gradient. Agricultural land use in the basin of the bay and fluxes of nutrients and sediments of the rivers entering the bay has significant contribution to the bay pollution situation. These results will serve as a guide for improving our understanding of the Gorgan Bay ecosystem. They also have implications for informed conservation and management plans adapted to the specifics of this special region within the Caspian Sea.

Effect of Rainfall on Water Parameters in Recreational Lakes in Heidelberg, Germany

This study evaluates the impact of precipitation on water quality in Heidelberg, Germany’s recreational lakes during sporadic rainfall events from August to September 2023. Data were collected from five stations, monitoring physicochemical properties and nutrient levels before and after rainfall. Measurements of dissolved oxygen, pH, conductivity, and redox potential were conducted in situ, while turbidity, nitrates, phosphates, sulphates, zinc, and copper levels were analyzed in the SRH Heidelberg water laboratory. Findings indicate pH levels increased due to dilution effects, while conductivity rose due to runoff, enhancing ion concentration in the lakes. Dissolved oxygen levels also increased, attributed to aeration from rainfall-induced surface turbulence. Redox potential decreased, reflecting atmospheric oxygen dissolution. Nutrient concentrations, including nitrates and phosphates, along with sulphates, declined post-rainfall, suggesting a dilution effect without significant impact from surface runoff. This outcome implies the absence of major nutrient and sulphate sources upstream. Heavy metals like zinc and copper also decreased in concentration, indicating no introduction through runoff or sediment transport. The study underscores the variability of water quality parameters across different lakes, influenced by factors such as water sources, surrounding land use, geological conditions, and lake characteristics. Overall, water quality improved post-rainfall, making the lakes suitable for recreational activities, with the study establishing a non-linear correlation among the water quality parameters and deducing the P ratio for each parameter.

Integrated Assessment of Kirala Kele Wetland Health: Bridging the Gap between Water Quality Parameters and Biotic Components

Abstract The present study was carried out to assess the health of the Kirala Kele Wetland, Sri Lanka, by coupling water quality indices and bioindicators. A total of 12 sampling sites were selected to represent different land-use patterns of the Kirala Kele Wetland using purposive sampling technique, and sampling was conducted from March 2021 to May 2021, on a monthly basis. Triplicated samples (n = 3) were obtained for each sampling event at each sampling site. Aquatic macroinvertebrates were collected from each site to determine the biological water quality using the Biological Monitoring Working Party (BMWP) score. Weighted Arithmetic Water Quality Index (WAWQI) was calculated to understand the physicochemical parameters of water, and the mean values of physicochemical water quality parameters were compared with the Sri Lankan water quality standards. According to the WAWQI for the different sampling sites, water is not suitable for drinking without treatment. The resulted BMWP score (BMWP = 61) shows that the water quality is acceptable (clean but slightly impacted) for biotic components of the wetland in accordance with the aquatic macroinvertebrates present. Spatial variation in water quality parameters and the aquatic macroinvertebrates were taken into account, and the temporal variation in water quality parameters within the 3 months from March to May was considered.

Temporal variation of water quality parameters in the lacustrine of the Thrace Region, Northwest Türkiye.

Thrace is a part of the Marmara Region northwest of Türkiye. This region hosts several lentic ecosystems used for irrigation and drinking water supply. The present study was conducted to analyze the temporal distributions of water quality parameters (WQPs) of lentic ecosystems (lacustrine habitats), including lakes (L1-L2), reservoirs (R1-R12), and ponds (P1-P19) of the Thrace Region. Thirty-three lacustrine habitats were identified in the region. Freshwaters were collected in the wet (end of winter) and dry (end of summer) seasons of 2021-2022 and tested for 12 WQPs. Data was evaluated for the water quality index (WQI) and nutrient pollution index (NPI) and their overall quality level. For the evaluation of non-carcinogenic health risk indices of WQPs, the chronic daily index (CDI), hazard quotient (HQ), and hazard index (HI) were applied. Cluster analysis (CA), Pearson correlation index (PCI), and principal component analysis (PCA) were used to classify the lacustrine habitats and identify the source of WQPs. The average values were as follows: 9.28mg/L for dissolved oxygen (DO), 94.6% for oxygen (O2) saturation, 9.29 for pH, 613 μS/cm for electrical conductivity (EC), 3.96 NTU for turbidity, 358mg/L for total dissolved solids (TDS), 3.17mg/L for nitrate (NO3), 0.05mg/L for nitrite (NO2), 1.01mg/L for phosphate (PO4), 78.5mg/L for sulfate (SO4), and 102mg/L for chloride (Cl). Results showed a significant increase in WQPs, including NO3, NO2, and PO4, in the wet season, while the salinity decreased from the dry to wet season. Results revealed that HI values of water contaminants in lacustrine habitats were noted to be less than one. Based on determined WQPs, the present study recommends using lacustrine water habitats for irrigation, drinking, and other domestic and industrial purposes.

A Study on Seasonal Variations in Water Quality Parameters of Dhaka Rivers

A Study on Seasonal Variations in Water Quality Parameters of Dhaka Rivers

Physiochemical Characteristics Analysis of Garrah River Water at Shahjahanpur, Ganga River Basin, Uttar Pradesh, India

This study focuses on the physiochemical analysis of the Garrah River in Shahjahanpur, within the Ganga River Basin, Uttar Pradesh, India. The research evaluates the impact of various pollutants, including industrial and municipal sewage, on the river's water quality. Water samples were collected from three locations along the river, representing different pollution levels. The analysis included parameters such as pH, dissolved oxygen (DO), total suspended solids (TSS), color, odor, electrical conductivity, temperature, chemical oxygen demand (COD), salinity, and the concentrations of various elements. The findings showed variations in water quality parameters, with DO, TSS, COD, and heavy metals indicating significant pollution, particularly downstream. Color and odor also suggested pollution from nearby industries. The study revealed that some parameters exceeded WHO standards for drinking water, raising concerns about health risks from exposure to contaminants like chromium. Urgent actions are required to treat municipal sewage and industrial effluents before discharging into the Garrah River. This research highlights the need for ongoing monitoring and sustainable management of water resources in the Ganga River Basin to protect the ecosystem and local communities. It underscores the importance of improving water quality in the region.

Wetland biodiversity of Ramaroshan Lake complex: a need for conservation

The Ramaroshan Lake Complex, situated in the mid-hills of Sudurpaschim Province, is renowned for its scenic beauty, yet there is a notable dearth of information regarding its biodiversity and ecological status. This study represents the first systematic examination of seasonal variations in water quality parameters and biodiversity encompassing aquatic macroinvertebrates, fishes, birds, herpetofauna, mammals, and macrophytes, as well as the surrounding vegetation within the complex, spanning the winters and summers of 2018 and 2019. Among the twenty water quality parameters investigated, thirteen displayed significant seasonal differences across the lakes (p <0.05), with Batula and Ramaroshan lakes exhibiting elevated nutrient levels. Lamadaya Lake stood out with a highly diverse macroinvertebrate community compared to other lakes, while overall, the study recorded 45 aquatic macroinvertebrate families, three fish species, 79 bird species, 12 herpetofauna species, 12 mammal species, and 26 macrophyte species within the complex. Additionally, the surrounding vegetation comprised 193 distinct plant species. Notably, the complex currently hosts 14 IUCN Red List species, including Near Threatened (5), Vulnerable (5), Critically Endangered (1), and Endangered (3) species, as well as five migratory wetland bird species, underscoring its significance for wildlife conservation. Given the diverse and cross-cutting nature of wetlands, the development of science-based policies and coordinated efforts among central, provincial, and local governments are essential for the preservation and sustainable management of these vital ecosystems.

A Comprehensive Study of Variation in Water Quality Parameters to Design a Sustainable Treatment Plant

In this paper, greywater samples are collected from the kitchens of different types of buildings (residential and commercial) located in different districts within the city of Jeddah, Saudi Arabia. The collected samples are analyzed and compared with the potable water from the same region. The parameters investigated are pH, conductivity, total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), total hardness, temporary hardness, permanent hardness, alkalinity, chloride, and biochemical oxygen demand (BOD). It was found that the amount of total suspended solids is very high in the greywater samples. It shows the presence of both temporary and permanent hardness. Their alkalinity values are greater than hardness. It may be due to the number, lifestyle, age of the occupants, presence of children, and social and cultural behavior of residents. The concentration of BOD level is very low, which shows that the greywater samples have lower concentrations of organic compounds. Design details of the greywater treatment plant are suggested based on the results of the analysis. This includes a screening chamber, grit chamber, settling tank, and filtration unit. The treated greywater is recommended for reuse for gardening, landscaping, and toilet flushing purposes.

Seasonal differences in water quality of highland lakes and its influencing factors: A case study of Dianchi Lake

Abstract Water quality is of great significance to human survival and development. It is of good theoretical value to study seasonal water quality variation and driving factors in plateau lakes. This paper studied the variation of water quality parameters in different seasons and their relationship with land use and climate factors in Dianchi Lake, Yunnan Province from 2001 to 2019. The results show that the factors restricting water environment in different seasons are different, but basically close. The water quality parameters of multiple water quality monitoring stations in different seasons showed a decreasing or insignificant trend. In the rainy season, the temperature and precipitation were positively correlated with most water quality parameters, while the driving effect of climate factors was not significant in the dry season. Different land types have different effects on water quality indexes in different seasons. The water quality score was higher in the rainy season than in the dry season. The scores of water quality stations in the south and middle of Dianchi Lake are higher than those in the north. In this study, the relationship between climate, land, and water quality is established, which provides a way for the research of water quality parameters.

Efficient purification of high-salt rural groundwater in the areas along the Yellow River in Henan Province, China, by hollow fiber membrane distillation process

The vast rural drinking water sources along the Yellow River basin in Henan Province mainly come from the local high-salinity groundwater, which cannot be directly drunk. Zeolitic imidazolate framework-71/polyvinylidene fluoride hollow fiber composite membrane was applied to treat rural groundwater through membrane distillation technology. The variations of water quality parameters from 12 different rural regions after membrane distillation treatment were well analyzed and compared. Membrane separation performance for water samples from different regions during the membrane distillation process was investigated, including water flux and salt rejection. During a continuous 24-h membrane distillation process for the treatment of these water samples, hollow fiber membrane exhibits high solute retention rates (>99%) for salt ions, suspended solids and total dissolved solids, which are within the limits of national standards (GB 5749-2006), meanwhile membrane permeation water flux can remain stable. After the acid-cleaning for 180 min, all hollow fiber membranes can recover water flux well with a flux recovery rate above 98%. Even if the concentration ratio continued to increase, the water production rate of membrane distillation was basically maintained between 50% and 60%, which was obviously higher than the 30% of the reverse osmosis process. The economic analysis confirmed that the water production cost varied between US$0.45 and US$0.29/m3. With the extension of membrane service life, the specific membrane cost decreased rapidly in the first 6 years and then leveled off. The proposed vacuum membrane distillation process proved to be a promising water purification method for treating rural high-salinity groundwater.

Investigating river water quality assessment through non‐parametric analysis: A case study of the Godavari River in India

AbstractThis study examines temporal variations in water quality parameters of Godavari River. The present study examines the concentrations of seven water quality parameters, namely total alkalinity (Alk), calcium (Ca), chlorine (Cl), total hardness (Hard), magnesium (Mg), sodium (Na), and sulfate (SO4), using data from 1981 to 2005 at seven gauging stations, that is, Mancherial, Pathagudem, Nowrangpur, Jagdalpur, Perur, Konta, and Polavaram. A seasonal analysis (pre‐monsoon, monsoon, and post‐monsoon) is conducted to detect trends in water quality parameters. The study also uses normality tests Kolmogorov–Smirnov (K–S) and Shapiro–Wilk (S–W) which reveals nonnormal distribution in the majority of datasets, necessitating non‐parametric analysis. The concentration of Alk, Ca, and Hard is found to be significantly increasing trend at some stations during all three seasons, along with significantly decreasing trend found in the concentrations of Cl, Na, and SO4 using non‐parametric Mann–Kendall's (M–K) and Sen's Slope test. The concentration of Mg depicts mixed trends at different stations which may be due the variation in agricultural practices or industrial activities surrounding the stations. It is evident that none of the parameter exhibits statistically significant trends across all seasons at any station. The results of Sen's Slope test are found to be in good agreement with Mann–Kendall's test statistics. A second order auto‐regressive model (AR (2)) is successfully employed to predict and forecast the water quality parameters in present and future time steps. The authenticity of AR (2) model is assessed using Nash‐Sutcliffe (NSE) efficiency and coefficient of determination (R2). The values of NSE and R2 are found to be more than 0.85 for all parameters during all the three seasons, along with, the values of mean square error (MSE), root mean square error (RMSE), and mean absolute error (MAE). The results of coefficient of variation (CV) and persistence‐criterion (PC) also depicts that AR (2) can successfully be utilized in forecasting the water quality parameters. The research contributes insights for effective water resource management in Godavari River basin.

Spatial-temporal variability analysis of water quality using remote sensing data: A case study of Lake Manyame

Worldwide, the quality of freshwater in inland water bodies has been a major issue of concern due to the negative impact of human activities. With the increase in global population, it is projected that the quality of the water resources will deteriorate. Quantitative information on the state of water quality is quite crucial in water resources planning and conservation. Conventional or ground-based measuring tools are more time demanding, expensive for monitoring water quality parameters of inland water bodies, resulting in incomprehensive coverage in time and space. Due to the paucity of images with fine spatial and temporal resolution like Sentinel 2, provides invaluable information at a fine spatial scale for water quality monitoring to supporting progress towards achieving Sustainable Developments Goals (SDGs). This study quantified the spatial and temporal variations of water quality parameters of Total Nitrogen (TN), Turbidity, Chlorophyll-a (Chl-a) and Total Suspended Matter (TSS) derived from cloud free and remotely sensed Sentinel 2 satellite data for a period from 2017 to 2022 for Lake Manyame in Zimbabwe. Furthermore, the research developed empirical models based on the linear regression between in-situ water sample data and water quality indicators of Sentinel 2. The results showed that between 2017 and 2022, the water quality in Lake Manyame significantly fluctuated. The regression coefficients (R²) between remote sensed water quality parameters and field or sample water data ranged from R² = 0.63 to R² = 0.95, providing a promising possibility for operational use of freely available remote sensing data in water quality monitoring in data constrained countries.The study demonstrated the importance and capability of using freely available Sentinel 2 data, with fine spatial and temporal resolution in providing invaluable information and evaluating on the state and indicators of water quality in inland water bodies in space and time. Such information is crucial in informing resource managers and decision makers in conserving water resources.

Temporal Variation of Water Quality Parameters during COVID-19: A Case Study of River Yamuna

Temporal Variation of Water Quality Parameters during COVID-19: A Case Study of River Yamuna

Mapping of tide-dominated Hooghly estuary water quality parameters using Sentinel-3 OLCI time-series data.

The study explores the spatio-temporal variation of water quality parameters in the Hooghly estuary, which is considered an ecologically-stressed shallow estuary and a major distributary for the Ganges River. The estimated parameters are chlorophyll-a, total suspended matter (TSM), and chromophoric dissolved organic matter (CDOM). The Sentinel-3 OLCI remote sensing imageries were analyzed for the duration of October 2018 to February 2019. We observed that the water quality of the Hooghly estuaries is comparatively low-oxygenated, mesotrophic, and phosphate-limited. Ongoing channel dredging for maintaining shipping channel depth keeps the TSM in the estuary at an elevated level, with the highest amount of TSM observed during March of 2019 (41.59g m-3) at station A, upstream point. Since the pre-monsoon season, TSM data shows a decreasing trend towards the mouth of the estuary. Chl-a concentration is higher during pre-monsoon than monsoon and post-monsoon periods, with the highest value observed in April at 1.09 mg m-3 in station D during the pre-monsoon period. The CDOM concentration was high in the middle section (January-February) and gradually decreased towards the estuary's head and mouth. The highest CDOM was found in February at locations C and D during the pre-monsoon period. Every station shows a significant correlation among CDOM, TSM, and Chl-a measured parameters. Based on our satellite data analysis, it is recommended that SNAP C2RCC be regionally used for TSM, Chl-a, and CDOM for water quality product retrieval and in various algorithms for the Hooghly estuary monitoring.

Depth profile of reservoir water quality in the Southwest of Ethiopia

The objective of this research was to investigate the variation of water quality parameters at different depths of the Gilgel Gibe I reservoir in Oromia Jimma zone during wet seasons. Five stations within the reservoir were selected, and water quality parameters were determined at four different depths (surface, 5 m, 10 m, and 15 m). Water quality parameters were analyzed on-site using a HACH, HQ40d portable multi-meter, and turbidity was measured using Wag tech turbidity meter and in the laboratory using the standard method. Comparison of water quality parameters among depths were conducted using one-way ANOVA and Tukey's pairwise comparisons with 5% significance level. The probable contributing source of the investigated physicochemical water quality parameters at different depth was identified using Principal components analysis. The results show that depth wise except for total suspended solids (TSS), total dissolved solids (TDS), total phosphorus (TP) and soluble reactive phosphorus (SRP) the rest showed statistically significant difference at p < 0.05 level. Negative correlations were found between depth and dissolved oxygen (DO), water temperature, pH, nitrate (N03-) and chlorophyll a (Chl.a) while positive correlations were found between electrical conductivity (EC), biochemical oxygen demand (BOD5), turbidity and N03-. The study revealed that the release of nutrients associated with increased concentration of BOD5 at the bottom depth caused low concentration of dissolved oxygen due to oxygen consumption. This was further aggravated through the decomposition of organic matter, indicating organic pollution resulting from runoff from the catchment. The presence of dense masses of blue-green algae in the pelagic zone of Gilgel Gibe I reservoir suggested the presence of ample nutrients for its blooming and significant reduction of water quality, indicating possible eutrophic conditions. Therefore, catchment management is required to protect aquatic life and the reservoir function as a whole from reservoir water quality degradation.

Interaction of physico-chemical parameters with Shannon-Weaver Diversity Index based on phytoplankton diversity in coastal water of Diu, India

Phytoplankton acts as carbon sinks due to photosynthetic efficacy and their diversity is expressed by SWDI (Shannon-Weaver Diversity Index), which depends on water quality parameters. The coastal water of Diu was studied for three seasons, and the relationship between different parameters and SWDI was established. Subsequently, an attempt was made to build up a prediction model of SWDI based on multilayer perceptron Artificial neural network (ANN) using the R programme. Analysis shows interrelationship between the water quality parameters and phytoplankton diversity is same in linear principal component analysis (PCA) and neural network model. Variations of different parameters depend on seasonal changes. The ANN model shows that ammonia and phosphate are key parameters that influence the SWDI of phytoplankton. Seasonal variation in SWDI is related to variation in water quality parameters, as explained by both ANN and PCA. Hence, the ANN model can be an important tool for coastal environmental interaction study.

Studies on Seasonal Variation of Water Quality Parameters of River Mara Bharali in Sonitpur District of Assam

Background: Freshwater is not only a finite resource but also essential for agriculture, industry and even human existence. The present investigation on seasonal water quality parameters was conducted in the remnants of old channel of river Jia Bharali called as Mara Bharali at Tezpur in the Sonitpur district of Assam from December, 2017 to November, 2020. Methods: Five sampling stations were selected that covers a stretch of 16.5 km. Physico-chemical parameters were determined seasonally by following the standard methods of APHA (1998) and Trivedy et al., 1987. The statistical analyses of the data were done by one way ANOVA using Statistical Package for Social Scientists. Result: TDS in monsoon in all the locations remained lowest (171.33a±3.059 mg/L at MB2) and highest in winter (320.11c±2.441 mg/L at MB3). The pH value is within the permissible limit except for site MB4 during the winter and post monsoon when the values were 6.38±0.146 and 6.44±0.039 respectively. Maximum DO of 7.878d±0.074 mg/L was observed at site MB1 during the winter season and minimum DO of 5.444a±0.047 mg/L was observed at site MB4 during the monsoon season. BOD was recorded below the tolerance limit of 3 mg/L in all sampling stations.

Spatiotemporal Variations in Water Quality of the Transboundary Shari-Goyain River, Bangladesh

This study aimed to investigate the seasonal and spatial variations in water quality parameters and determine the main contamination sources in the Shari-Goyain River, Bangladesh. Therefore, surface water was sampled monthly from six sampling sites, where six water quality parameters were evaluated. Data were analyzed by applying the Canadian Council of Ministers of the Environment (CCME) water quality index (WQI) and multivariate statistical methods. The results reveals that most of the examined water quality parameters crossed the acceptable range, and significant variations were observed spatiotemporally (p &lt; 0.05). Based on the CCME WQI value, the water quality of the river is classified as poor to marginal with a score range between 33.40 and 51.30. This range of values demonstrates that the river’s water quality is far from desirable for aquatic life and that it is being impacted and deteriorated by external drivers. Principal component analysis (PCA) retained two principal components (Factors 1 and 2), explaining about 79.17% of the total variance in the studied parameters and identified acidic pollution sources. Cluster analysis also reveals relative differences in water quality throughout sites and seasons, which supported the CCME WQI and PCA. Finally, Kruskal-Wallis one-way analysis of variance by ranks has identified coal mine drainage (CMD) as the main pollutant source for the Shari-Goyain River. In order to mitigate the CMD impact on land and water, different nature-based solutions are proposed, particularly passive mine water treatment approaches through constructed wetlands that could also mitigate the transboundary waters problem.

Multivariate Analysis of the Dynamics in Water Quality and Trophic Status of the Crocodile River and Hartbeespoort Dam

Economic expansion coupled with population growth and associated anthropogenic activities are a threat to water resources globally. This study assessed the dynamics in water quality and trophic status of one of South Africa's hyper-eutrophic reservoirs, the Hartbeespoort Dam. Spatio-temporal variability in water quality parameters was determined on historical data spanning a period of forty years (1980-2020), with the aim of determining decadal changes in the Water Quality Index (WQI), the Water Pollution Index (WPI), the Canadian Council of Ministers of the Environment-Water Quality Index (CCME-WQI) as well as the Nutrient Pollution Index (NPI) and TN:TP ratios in the Hartbeespoort Dam as well as the Crocodile River. The calculated indices provide a single aggregated standardized score of water quality. The efficiency of a bioremediation programme (2007-2012) implemented as a mitigation measure to combat eutrophication in the dam was assessed. The study also investigated the impact of rainfall on the variability of the concentration and level of selected physico-chemical parameters. The results of the study revealed that apart from turbidity, rainfall has no significant impact on the variability of other water quality parameters studied. Furthermore, the WQI, CCME-WQI, WPI, as well as the NPI classified the general water quality of the dam as extremely poor and highly polluted. Moreover, TN:TP showed an increase in TP over time, further exacerbating hypereutrophic conditions in the catchment. The study also showed that the bioremediation programme was effective in reducing external P loading, however, bioturbation resulted in the resuspension of historical internal P loads, thus maintaining high phosphate concentrations at the site downstream from the Hartbeespoort Dam.