scholarly journals Impact of Urban Stormwater Runoff on Cyanobacteria Dynamics in A Tropical Urban Lake

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 946 ◽  
Author(s):  
Talita F. G. Silva ◽  
Brigitte Vinçon-Leite ◽  
Bruno J. Lemaire ◽  
Guido Petrucci ◽  
Alessandra Giani ◽  
...  
Keyword(s):  
Water Quality ◽  
Hydrological Model ◽  
Integrated Modelling ◽  
Wet Season ◽  
Lake Water Quality ◽  
Runoff Water ◽  
Large Lakes ◽  
Wide Range ◽  
The Impact ◽  
Modelling Approach

Worldwide, eutrophication and cyanobacteria blooms in lakes and reservoirs are a great concern for water resources management. Coupling a catchment hydrological model and a lake model has been a strategy to assess the impact of land use, agricultural practices and climate change on water quality. However, research has mainly focused on large lakes, while urban reservoirs and their catchments, especially in tropical regions, are still poorly studied despite the wide range of ecosystem services they provide. An integrated modelling approach coupling the hydrological model Storm Water Management Model SWMM and the lake ecological model DYRESM-CAEDYM is proposed for Lake Pampulha (Brazil). Scenarios of increased imperviousness of the catchment and of reduction in the load of nutrients and total suspended solids (TSS) in dry weather inflow were simulated. Runoff water quality simulations presented a fair performance for TSS and ammonium (NH4+) while the dynamics of total phosphorus (TP) and nitrate (NO3−) were poorly captured. Phytoplankton dynamics in the lake were simulated with good accuracy (Normalized Mean Absolute Error, NMAE = 0.24 and r = 0.89 in calibration period; NMAE = 0.55 and r = 0.54 in validation period). The general trends of growth, decline and the magnitude of phytoplankton biomass were well represented most of the time. Scenario simulations suggest that TP reduction will decrease cyanobacteria biomass and delay its peaks as a consequence of orthophosphate (PO43−) concentration reduction in the lake surface layers. However, even decreasing TP load into Lake Pampulha by half would not be sufficient to achieve the water quality objective of a maximum concentration of 60 µg chla L−1. Increased imperviousness in the catchment will raise runoff volume, TSS, TP and NO3− loads into Lake Pampulha and promote greater cyanobacteria biomass, mainly in the beginning of the wet season, because of additional nutrient input from catchment runoff. Recovering Lake Pampulha water quality will require the improvement of the sanitation system. The lake water quality improvement will also require more sustainable and nature-based solutions for urban drainage in order to reduce non-point pollution through infiltration and retention of stormwater and to enhance natural processes, such as chemical sorption, biodegradation and phytoremediation. The integrated modelling approach here proposed can be applied for other urban reservoirs taking advantage of existing knowledge on Lake Pampulha.

scholarly journals Citizen Science Tools Reveal Changes in Estuarine Water Quality Following Demolition of Buildings

2021 ◽  
Vol 13 (9) ◽  
pp. 1683
Author(s):  
Nandini Menon ◽  
Grinson George ◽  
Rajamohananpillai Ranith ◽  
Velakandy Sajin ◽  
Shreya Murali ◽  
...  
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Citizen Science ◽  
Secchi Depth ◽  
Lake Water Quality ◽  
Demolition Waste ◽  
Water Colour ◽  
Water Quality Variables ◽  
The Impact

Turbidity and water colour are two easily measurable properties used to monitor pollution. Here, we highlight the utility of a low-cost device—3D printed, hand-held Mini Secchi disk (3DMSD) with Forel-Ule (FU) colour scale sticker on its outer casing—in combination with a mobile phone application (‘TurbAqua’) that was provided to laymen for assessing the water quality of a shallow lake region after demolition of four high-rise buildings on the shores of the lake. The demolition of the buildings in January 2020 on the banks of a tropical estuary—Vembanad Lake (a Ramsar site) in southern India—for violation of Indian Coastal Regulation Zone norms created public uproar, owing to the consequences of subsequent air and water pollution. Measurements of Secchi depth and water colour using the 3DMSD along with measurements of other important water quality variables such as temperature, salinity, pH, and dissolved oxygen (DO) using portable instruments were taken for a duration of five weeks after the demolition to assess the changes in water quality. Paired t-test analyses of variations in water quality variables between the second week of demolition and consecutive weeks up to the fifth week showed that there were significant increases in pH, dissolved oxygen, and Secchi depth over time, i.e., the impact of demolition waste on the Vembanad Lake water quality was found to be relatively short-lived, with water clarity, colour, and DO returning to levels typical of that period of year within 4–5 weeks. With increasing duration after demolition, there was a general decrease in the FU colour index to 17 at most stations, but it did not drop to 15 or below, i.e., towards green or blue colour indicating clearer waters, during the sampling period. There was no significant change in salinity from the second week to the fifth week after demolition, suggesting little influence of other factors (e.g., precipitation or changes in tidal currents) on the inferred impact of demolition waste. Comparison with pre-demolition conditions in the previous year (2019) showed that the relative changes in DO, Secchi depth, and pH were very high in 2020, clearly depicting the impact of demolition waste on the water quality of the lake. Match-ups of the turbidity of the water column immediately before and after the demolition using Sentinel 2 data were in good agreement with the in situ data collected. Our study highlights the power of citizen science tools in monitoring lakes and managing water resources and articulates how these activities provide support to Sustainable Development Goal (SDG) targets on Health (Goal 3), Water quality (Goal 6), and Life under the water (Goal 14).

scholarly journals Seasonal changes in water quality and macrophytes and the impact of cattle on tropical floodplain waterholes

2012 ◽  
Vol 63 (9) ◽  
pp. 788 ◽  
Author(s):  
N. E. Pettit ◽  
T. D. Jardine ◽  
S. K. Hamilton ◽  
V. Sinnamon ◽  
D. Valdez ◽  
...  
Keyword(s):  
Water Quality ◽  
Seasonal Changes ◽  
Aquatic Macrophyte ◽  
Plant Cover ◽  
Critical Role ◽  
Dry Season ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Dry Tropics ◽  
The Impact

The present study indicates the critical role of hydrologic connectivity in floodplain waterholes in the wet–dry tropics of northern Australia. These waterbodies provide dry-season refugia for plants and animals, are a hotspot of productivity, and are a critical part in the subsistence economy of many remote Aboriginal communities. We examined seasonal changes in water quality and aquatic plant cover of floodplain waterholes, and related changes to variation of waterhole depth and visitation by livestock. The waterholes showed declining water quality through the dry season, which was exacerbated by more frequent cattle usage as conditions became progressively drier, which also increased turbidity and nutrient concentrations. Aquatic macrophyte biomass was highest in the early dry season, and declined as the dry season progressed. Remaining macrophytes were flushed out by the first wet-season flows, although they quickly re-establish later during the wet season. Waterholes of greater depth were more resistant to the effects of cattle disturbance, and seasonal flushing of the waterholes with wet-season flooding homogenised the water quality and increased plant cover of previously disparate waterholes. Therefore, maintaining high levels of connectivity between the river and its floodplain is vital for the persistence of these waterholes.

scholarly journals Climate-dependent propagation of precipitation uncertainty into the water cycle

2020 ◽  
Author(s):  
Ali Fallah ◽  
Sungmin O ◽  
Rene Orth
Keyword(s):  
Hydrological Model ◽  
Water Cycle ◽  
State Of The Art ◽  
Rain Gauge ◽  
Multiple Sources ◽  
Current State ◽  
Wide Range ◽  
The Impact ◽  
Conceptual Hydrological Model

Abstract. Precipitation is a crucial variable for hydro-meteorological applications. Unfortunately, rain gauge measurements are sparse and unevenly distributed, which substantially hampers the use of in-situ precipitation data in many regions of the world. The increasing availability of high-resolution gridded precipitation products presents a valuable alternative, especially over gauge-sparse regions. Nevertheless, uncertainties and corresponding differences across products can limit the applicability of these data. This study examines the usefulness of current state-of-the-art precipitation datasets in hydrological modelling. For this purpose, we force a conceptual hydrological model with multiple precipitation datasets in > 200 European catchments. We consider a wide range of precipitation products, which are generated via (1) interpolation of gauge measurements (E-OBS and GPCC V.2018), (2) combination of multiple sources (MSWEP V2) and (3) data assimilation into reanalysis models (ERA-Interim, ERA5, and CFSR). For each catchment, runoff and evapotranspiration simulations are obtained by forcing the model with the various precipitation products. Evaluation is done at the monthly time scale during the period of 1984–2007. We find that simulated runoff values are highly dependent on the accuracy of precipitation inputs, and thus show significant differences between the simulations. By contrast, simulated evapotranspiration is generally much less influenced. The results are further analysed with respect to different hydro-climatic regimes. We find that the impact of precipitation uncertainty on simulated runoff increases towards wetter regions, while the opposite is observed in the case of evapotranspiration. Finally, we perform an indirect performance evaluation of the precipitation datasets by comparing the runoff simulations with streamflow observations. Thereby, E-OBS yields the best agreement, while furthermore ERA5, GPCC V.2018 and MSWEP V2 show good performance. In summary, our findings highlight a climate-dependent propagation of precipitation uncertainty through the water cycle; while runoff is strongly impacted in comparatively wet regions such as Central Europe, there are increasing implications on evapotranspiration towards drier regions.

scholarly journals Exploring the water quality driving mechanism in Poyang Lake, the largest freshwater lake in China

2019 ◽  
Vol 20 (2) ◽  
pp. 700-711 ◽  
Author(s):  
Hua Wang ◽  
John Paul Kaisam ◽  
Shaowen Fang ◽  
Yanqing Deng ◽  
Bao Li ◽  
...  
Keyword(s):  
Water Quality ◽  
Atmospheric Deposition ◽  
Poyang Lake ◽  
Freshwater Lake ◽  
Driving Mechanism ◽  
Ecosystem Structure ◽  
Lake Water Quality ◽  
Sediment Release ◽  
The Impact ◽  
Boundary Input

Abstract Poyang Lake, the largest freshwater lake and typical river-connected lake in China, was selected as a research area. A method was first proposed to quantitatively explore the mechanisms driving water quality evolution, in which the weights of horizontal boundary input, self-purification, vertical atmospheric deposition and sediment release could be determined. A two-dimensional water environment model for Poyang Lake was developed in the framework of the Finite Volume Method and calibrated against the field investigated data. Four typical months in a common-water year were determined for numerical experiments to investigate the temporal and spatial water quality driving mechanisms in Poyang Lake. The results suggested that boundary input and self-purification have the greatest effect on dominating the water quality in Poyang Lake, followed by atmospheric deposition and sediment release. The driving weights of these four factors are 57.2%, 26.5%, 9.3%, and 7.0%, respectively. However, the impact on lake water quality of external water quality, aquatic ecosystem structure, precipitation distribution, and meteorological conditions, which are attributed to the disparities in geographical situation, varied significantly with seasons and locations.

Wet weather water quality modelling of a Portuguese urban catchment: difficulties and benefits

2002 ◽  
Vol 45 (3) ◽  
pp. 131-140 ◽  
Author(s):  
L.M. David ◽  
R.S. Matos
Keyword(s):  
Water Quality ◽  
River Flow ◽  
Integrated Approach ◽  
Integrated Modelling ◽  
Sewer System ◽  
Deterministic Modelling ◽  
Short And Long Term ◽  
Long Term Impact ◽  
The Impact

This paper discusses the use of water quality deterministic modelling together with an integrated approach to assess the impact of urban stormwater discharges into ephemeral watercourses, based on the study of a Portuguese catchment. The description of the main aspects, difficulties and benefits found during data collection and model calibration and verification is presented, and the associated uncertainties and errors discussed. Experimental results showed a strong short- and long-term impact of sewer discharges on rivers, and confirmed deposition, resuspension and transport of pollutants as important processes for the water quality. However, the resuspension of riverbed sediment pollutants during storms was probably more significant than the direct impact of the urban discharges. The HydroWorks™ model was used since it allows for the calculation of pollutant build-up on catchment surfaces and in gully pots, their wash-off, and the deposition and erosion of sediments in sewers. However, it uses several constants, which could not be independently calibrated, increasing the uncertainty already associated with the data. River flows have quite different magnitude from the sewer system overflows, which, together with the difficulties in evaluating river flow rates, makes the integrated modelling approach rather complex and costly.

Sediment content and chemical properties of water runoff on biocrusts in drylands

Biologia ◽  
2014 ◽  
Vol 69 (11) ◽  
Author(s):  
Roberto Lázaro ◽  
Juan Mora
Keyword(s):  
Dry Matter ◽  
Chemical Properties ◽  
Soil Surface ◽  
Water Erosion ◽  
Rainfall Simulation ◽  
Water Runoff ◽  
Protective Capacity ◽  
Runoff Water ◽  
Wide Range ◽  
The Impact

AbstractIn drylands, water erosion can be a process with important economic and ecological implications, and is very dependent on the soil surface cover. There is broad agreement that biocrusts protect the soil from erosion in a wide range of circumstances. However, there is little information available on the effect of rain and biocrust types on this protective capacity and there is particularly very little knowledge on the erosive effects of runoff on biocrusts, which are expected to be larger in larger drainage areas, on the resistance of biocrusts to the combined effect of raindrops plus runoff flow and on the solute mobilisation by runoff in biocrusts. To answer these questions, we performed 96 rainfall-simulation in situ factorial experiments, including two biocrust types (cyanobacteria and lichens), three rain types (42, 63 and 77 mm h−1, always 20 min rain), four plot lengths (1, 2, 3 and 4 m long) and four replicates. In each experiment, runoff volume was measured and a runoff sample was taken to determine (i) the amount of dry matter in runoff, (ii) the amount of organic matter among the dry matter, (iii) the electrical conductivity, pH and alkalinity in runoff water. The main findings were: biocrusts strongly protected soil against water erosion, even under the most erosive conditions, and the protection increased with the successional development. Biocrusts were very resistant to the impact of raindrops and also to runoff flow, although an emergent hypothesis arose: under the most erosive conditions, a threshold of erodibility could be reached at the cyanobacterial biocrust. The lichen crust also protected the soil against the removal of soil soluble substances. The development of a biocrust could change the chemical composition of the solutes in runoff.

scholarly journals Assessment of the Impact of Land Cover Type on the Water Quality in Lake Tondano Using a SWAT Model

2021 ◽  
Vol 56 (1) ◽  
Author(s):  
Moh Sholichin ◽  
Tri Budi Prayogo
Keyword(s):  
Water Quality ◽  
Land Cover ◽  
Agricultural Land ◽  
Assessment Tool ◽  
Swat Model ◽  
Coefficient Of Determination ◽  
Organic N ◽  
Lake Water Quality ◽  
Total N ◽  
The Impact

Lake Tondano is the largest natural lake in North Sulawesi, Indonesia, which functions as a provider of clean water, hydroelectric power, rice field irrigation, inland fisheries, and tourism. This research aims to determine the effect of land cover types from the Tondano watershed on the lake water quality. The Soil and Water Assessment Tool (SWAT) model was used to evaluate the rate of soil erosion and the pollutant load of various land types in the watershed during the last ten years. Rainfall data is obtained from two rainfall stations, namely Paleloan Station and Noonan Station. The model is calibrated and validated before being used for analysis. We use climatological data from 2014 to 2019. The process of the SWAT model calibration and validation was carried out with the statistical formulas of the coefficient of determination (R2) and Nash-Sutcliffe efficiency (NSE). The results show that the potential for pollution load from the Tondao watershed is organic N of 0.039 kg/ha and organic P of 0.006 kg/ha coming from the agricultural land. The results of this study conclude that the fertility conditions of Lake Tondano are at the eutrophic level, where the pollutant inflow is collected in the lake waters, especially for the parameters of total N (1503697.44kg/year) and total P (144831.36kg/year). The SWAT simulation results show deviation between the modeling and field data collected with the value of R2 = 0.9303, and the significant level ≤ 10.

scholarly journals Impact of Encroachment and Hyderabad City Effluents on Pinyari Canal

2020 ◽  
Vol 10 (3) ◽  
pp. 5784-5789
Author(s):  
A. A. Mahessar ◽  
K. Ansari ◽  
A. L. Qureshi ◽  
K. C. Mukwana ◽  
A. A. Pathan ◽  
...  
Keyword(s):  
Water Quality ◽  
Socioeconomic Development ◽  
Left Bank ◽  
Wet Season ◽  
Wastewater Disposal ◽  
Untreated Wastewater ◽  
Quality Issue ◽  
Drinking Purposes ◽  
Growth Changes ◽  
The Impact

Pinyari canal off-takes from the left bank of Kotri barrage with a design discharge of 13,636 cusecs which passes through the ridge of Hyderabad city along with New Fuleli Canal and Akram Wah on its left side. Its water is used for irrigation, agriculture, industrial, domestic, and drinking purposes in Hyderabad and Sajawal districts in Sindh. This canal is non-perennial. Water is being released with low discharge only for drinking purposes during the dry season and with full supply in the wet season. The global water quality issue reflects the major impact of socioeconomic development and population growth changes on freshwater resources including canals and rivers. This paper presents the impact of untreated wastewater disposal to the canal. The practice of disposing of untreated effluents has created serious health and environmental problems for the locals. The statistical and geospatial tool GIS has been used for the assessment of water quality with visualization of wastewater behavior in the canal. The results of the statistical analysis showed that pH was within the permissible limits but Electric Conductivity (EC), Total Dissolved Solids (TDS), Sodium (Na), and Hardness exceed them. The Water Quality Index of the samples rated from very poor to unsuitable for drinking, hence, canal water is unfit for domestic use or drinking purposes.

scholarly journals Modelling a river catchment using an electrical circuit analogue

1998 ◽  
Vol 2 (1) ◽  
pp. 9-18 ◽  
Author(s):  
C. G. Collier
Keyword(s):  
Input Data ◽  
River Flow ◽  
Hydrological Model ◽  
Analytic Solution ◽  
Electrical Circuit ◽  
Physical Processes ◽  
River Catchment ◽  
Analogue Research ◽  
The Impact ◽  
Modelling Approach

Abstract. An electrical circuit analogue of a river catchment is described from which is derived an hydrological model of river flow called the River Electrical Water Analogue Research and Development (REWARD) model. The model is based upon an analytic solution to the equation governing the flow of electricity in an inductance-capacitance-resistance (LCR) circuit. An interpretation of L, C and R in terms of catchment parameters and physical processes is proposed, and tested for the River Irwell catchment in northwest England. Hydrograph characteristics evaluated using the model are compared with observed hydrographs, confirming that the modelling approach does provide a reliable framework within which to investigate the impact of variations in model input data.

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