Long-term monitoring and proposed diffuse pollution control of a tropical reservoir

2007 ◽  
Vol 55 (3) ◽  
pp. 161-166 ◽  
Author(s):  
E. von Sperling ◽  
A.D. Souza

This paper presents the results of 30 years of water quality monitoring in a tropical water supply reservoir (Vargem das Flores, Brazil). This water body is subjected to eutrophication problems caused by point sources (discharge of untreated sewage) and diffuse pollution (agricultural use in the drainage basin). Emphasis is given here on the estimation of nutrient loads and on the study of the N/P ratio in the water body. In spite of the prevalence of high N/P values, there is a clear trend in the dominance of cyanobacteria in the phytoplankton, which contradicts results from research in temperate aquatic environments. Some restoration measures for Vargem das Flores Reservoir are currently being implemented: construction of wastewater treatment plants, control of recreational activities, erosion control by hydroseeding and use of natural wetlands. Finally some management strategies in order to prevent algae input in the water abstraction system are discussed. Examples of these techniques are the installation of plastic barriers and the construction of an air curtain device.

2007 ◽  
Vol 55 (3) ◽  
pp. 115-122 ◽  
Author(s):  
A. Erturk ◽  
M. Gurel ◽  
E. Varol ◽  
A. Ekdal ◽  
M. Baloch ◽  
...  

Diffuse pollution is usually temporally and spatially uncertain, and thus hard to analyze. In many cases, discretizing a diffuse source of pollution into individual point sources can ease diffuse pollution modelling and analysis, and therefore reduce high uncertainty especially in the spatial distribution of pollution loads. This is however a difficult task, since quite a number of sub-drainage areas, with complex structures and land-use properties, has to be delineated. Watershed models can be used to delineate the sub-drainage areas in a watershed with high accuracy and locate the related outlets which connect the sub-drainage areas to the main waterbody in a watershed. In this study, such an approach has been used on a case study to model the diffuse nutrient loads carried to streams that reach to a medium-sized lake in Turkey. The annual nutrient loads, which were calculated by using mathematical models, were then converted to a load-map with the help of a geographical information system.


1999 ◽  
Vol 39 (12) ◽  
pp. 299-305 ◽  
Author(s):  
Jan McNitt ◽  
Ron Kepford

To control pollution attributable to livestock operations, the statutory and regulatory scheme of the US Clean Water Act focuses on implementing structural controls to contain animal waste. While the United States Environmental Protection Agency (USEPA) is empowered only to regulate point sources, existing authority may be extended to regulate diffuse runoff associated with certain livestock facilities. Current water pollution abatement programs, however, have not responded to the differences inherent in diffuse pollution and the land management strategies necessary to control and abate its impacts. The Planned Intervention Micro-watershed Approach (PIMA) recognizes this distinction, offering a method of refining land management strategies while keeping existing point source pollution regulation and enforcement mechanisms in place. Within a limited time frame, producers have flexibility to develop and implement cost-effective management practices that achieve environmental goals. Planned intervention is integrated with a micro-watershed approach to watershed management which uses small, hydrologically discrete areas to target diffuse pollution sources and direct intervention efforts. This approach utilizes local stakeholder input and participation to create a bottom-up, community-based institutional framework for addressing diffuse pollution from agricultural sources that satisfies water quality objectives.


1993 ◽  
Vol 28 (3-5) ◽  
pp. 69-78 ◽  
Author(s):  
G. Bendoricchio ◽  
M. Di Luzio ◽  
P. Baschieri ◽  
A. G. Capodaglio

The hypertrophic conditions of several confined areas in the Lagoon of Venice are but one of the consequences of nutrient discharges from its drainage basin. The monthly distribution of these loads, as well as their spacial subdivision among different tributaries of this characteristic water body, directly affect the growth cycle of macroalgae in it. The magnitude of these loads cannot be precisely measured by direct methods, however, it can be estimated by simulation with appropriate models. A comprehensive study aimed at the determination of these loads is under way as part of a larger intervention program to restore the physical and ecological equilibrium of the Lagoon. This paper focuses on the results of the simulation of diffuse loads generated in the Lagoon watershed. These results were obtained by interfacing a geographical information system (GIS) of the watershed and two models simulating respectively urban and agricultural diffuse pollution. Diffuse loads are then compared with the corresponding point sources to evaluate their relative contributing role in the dystrophic behavior of the Lagoon. The relative importance of diffuse sources is discussed with particular reference to time and space variability of the loads.


2005 ◽  
Vol 51 (3-4) ◽  
pp. 309-317 ◽  
Author(s):  
A. Vassiljev ◽  
P. Stålnacke

Implementation of the Water Framework Directive calls for methodologies and tools to quantify nutrient losses from diffuse sources at a river basin district scale. Here, we examine the possibility of using a statistical model for source apportionment and retention of nutrients in a large transboundary drainage basin (44,000 km2). The model approach uses non-linear regression for simultaneous estimation of e.g. source strength, i.e. export coefficients to surface waters, for the different specified land-use or soil categories and retention coefficients for pollutants in a drainage basin. The model was tested on data from 26 water quality stations with corresponding sub-basin data, i.e., land cover, point sources and atmospheric deposition, from the Estonian part of the Lake Peipsi drainage basin. The model showed that it was statistically possible to derive reliable export coefficients (i.e. unit-area loads) for nitrogen on agricultural land and forests. Moreover, it was shown with simple empirical functions that lake retention was approximately 30-35% for both nitrogen and phosphorus and that the riverine retention was low for both nitrogen and phosphorus (approx. 10%). Results show that the MESAW model is a simple and powerful tool for simultaneous estimation of sources and retention of nutrient loads in a river basin.


Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 457
Author(s):  
Raju Sekar ◽  
Xin Jin ◽  
Shuang Liu ◽  
Jing Lu ◽  
Jianwei Shen ◽  
...  

Freshwaters in China are affected by point and non-point sources of pollution. The Wujiang District (Suzhou City, China) has a long history of canals, rivers, and lakes that are currently facing various water quality issues. In this study, the water quality of four rivers and a lake in Wujiang was assessed to quantify pollution and explore its causes. Seventy-five monthly samples were collected from these water bodies (five locations/samples per area) from August to October 2020 and were compared with nine control samples collected from a water protection area. Fifteen physicochemical, microbiological, and molecular–microbiological parameters were analyzed, including nutrients, total and fecal coliforms, and fecal markers. Significant monthly variation was observed for most parameters at all areas. Total phosphorus, phosphates, total nitrogen, ammonium–nitrogen, and fecal coliforms mostly exceeded the acceptable limits set by the Chinese Ministry of Environmental Protection. The LiPuDang Lake and the WuFangGang River were the most degraded areas. The studied parameters were correlated with urban, agricultural, industrial, and other major land use patterns. The results suggest that fecal contamination and nutrients, associated with certain land use practices, are the primary pollution factors in the Wujiang District. Detailed water quality monitoring and targeted management strategies are necessary to control pollution in Wujiang’s watersheds.


1998 ◽  
Vol 38 (11) ◽  
pp. 141-148 ◽  
Author(s):  
P. Marjanovic ◽  
M. Miloradov

The new National water policy will change the way water quality is managed in South Africa. The paper considers the water policy and the repercussions it will have for water quality monitoring in South Africa. Using the systems approach the paper discusses an integrated water quality monitoring system for ambient water quality and point and non point sources of aquatic pollution. The proposed methodology makes possible continuos assessment of water quality in an efficient manner so as to support water quality management in South Africa.


2021 ◽  
Author(s):  
Russell Adams ◽  
Donnacha Doody

<p>Northern Ireland has been somewhat overlooked in terms of water quality modelling in the past. Many of its catchments have consistently failed to meet Water Framework Directive targets especially due to high levels of dissolved nutrients and poor ecological status. A catchment based modelling study to address this issue has not been undertaken here previously and the approach described here uses two water quality models to achieve this aim. The objectives of the modelling were firstly to identify the total load reductions (in terms of Phosphorus (P)) required to reduce in-stream loadings sufficiently for concentrations of soluble reactive P (SRP) to be reduced to achieve the WFD “Good” status levels, and secondly to split these loadings into diffuse and point components. The third objective was to identify the most likely flow pathways for the transport of the diffuse component of P to the watercourses particularly for the agricultural (mostly intensive grassland farming) land use which dominates in almost all NI catchments.</p><p>The first model applied is the Source Load Apportionment Model (SLAM) developed by the Irish EPA. This model provides a large-scale assessment of the point and diffuse load components across catchments where multiple pressures are occurring. The second model us the Catchment Runoff Flux Assessment Tool (CRAFT) which is able to back-calculate nutrient loads associated with three major flow pathways. SLAM is a static model which uses averaged loadings from diffuse agriculture and non-agricultural land uses, and point sources (where information can be obtained from various sources) to calculate N and P exports. For P, the agricultural diffuse load component uses an enhanced version of the export coefficient approach based on combining the sources of P from applied nutrients (slurry and fertiliser) and soil P. A modelling tool allows the user to evaluate load reduction scenarios where one or several components of P (both point and diffuse) are adjusted downwards to achieve the catchment’s required load reduction. The CRAFT model works on a dynamic (daily) modelling scale and has simulated sub-catchments where the SLAM model has identified the need for significant load reductions. It identifies the different reductions (P export) that are required for each flow pathway, which will then inform on the type of additional measures (e.g. sediment traps, riparian buffer strips and wetlands) that may also be required.</p><p>The initial aim of this study is to complete a pilot application to the trans-border (UK and ROI) Blackwater catchment (1360 km<sup>2</sup>). Through a review of alternative modelling options for the whole area of NI, an assessment of whether this approach is suitable for application to the entire territory can be made.</p>


2018 ◽  
Vol 1 ◽  
Author(s):  
Sanda Iepure ◽  
Nicolas Gouin ◽  
Angeline Bertin ◽  
Ana Camacho ◽  
Antonio González-Ramón ◽  
...  

Chile has large extensions of arid and semi-arid regions throughout the whole country, where the intensive demands and use of water resources, especially groundwater for irrigations and mining activities, increased dramatically over the last decades. The aquifer depletions due to water abstraction for irrigation and nutrient loads, exert major alterations of water quality, groundwater recharge and the natural renewal rate. All these factors diminish the aquifer value for the users and contribute to the degradation of groundwater as environment and habitat for fauna. This intensive use of groundwater resources in Chile brought to significant social and economic benefits, but their inadequate management resulted in negative environmental, legal and socioeconomic consequences. In this study, we aimed at providing a first assessment of environmental alterations of groundwater ecosystems from agricultural watersheds in northern Chile by specifically evaluating the effects of nitrogen and pesticide loads on groundwater communities and identifing the ecosystem service alterations due to agricultural activities. The study has been performed in a glacial aquifer from Coquimbo region; 250 km north of Santiago de Chile, the floodplain of which is dominated by agriculture (fruits tress, vineyards). Due to low regional precipitations (100-240 mm/year) the aquifer is primarily recharged by snowmelt from the Andean chain and surface runoff. The relative groundwater levels, groundwater temperature, chemical analysis of nitrogen and total phosphorus and pesticide concentrations were examined, along with the evaluation of crustacean biodiversity and spatial distribution pattern. Stygofauna taxonomic richness and the presence of stygobites have been related more to groundwater level stability than to chemical water parameters indicating that over-exploitation has a negative impact on habitat suitability for groundwater invertebrates. Groundwater biota assessment is essential in understanding the impact produced by agriculture activities on groundwater as a resource and as ecosystem, a nexus that becomes more and more widely recognized. The rationale and the preliminary results of this study are summarized in the Suppl. material 1.


2016 ◽  
Vol 5 (1) ◽  
pp. 110 ◽  
Author(s):  
Eva Pip ◽  
Kimber Munford ◽  
Lindsay Bowman

Seasonal fluctuation patterns of the neurotoxic amino acid β N methylamino L alanine (BMAA) were examined at four-day intervals during the ice-free season in water at three nearshore stations in the south basin of Lake Winnipeg, Canada. BMAA patterns were significantly exponentially correlated with concurrent phaeophytin, and inversely with chlorophyll a, indicating that free BMAA concentrations increased as blooms declined. BMAA was also significantly related to preceding microcystin concentrations, and as chlorophyll a declined, the proportion of BMAA relative to microcystin increased. Cross correlations identified significant relationships between BMAA and immediately preceding nitrate-N/inorganic phosphorus ratios, nitrate-N, rainfall, and a marginal inverse correlation with inorganic phosphorus. Total suspended solids levels were also significantly associated with BMAA, likely due to shading effects. A very high BMAA concentration was found under collapse of intense bloom conditions. These results have implications for water quality monitoring, nutrient management strategies and public health.


Author(s):  
L. O. Bobor ◽  
C. M. Umeh

The indiscriminate disposal of industrial effluents and solid wastes in surface water bodies is detrimental to humans and aquatic organisms. Water quality monitoring is critical to identify pollutants of concern and develop effective management strategies. Hence, this study was conducted to assess the impact of waste disposal on the water quality of Aba Waterside River, Ogbor hill, Aba. Grab samples were collected upstream, midstream and downstream and some physicochemical and microbiological parameters were analyzed in accordance with standard methods for the analysis of water and wastewater. The results were compared with the Nigerian standard for drinking water quality and the national environmental effluent limitation regulations. Turbidity levels (10 -31mg/l) exceeded the maximum permissible levels for drinking water (5mg/l) and may be associated with higher levels of embedded disease-causing microbes and potentially harmful organic and inorganic substances. The biological oxygen demand midstream (1960mg/l) was remarkably high due to the effluent discharged from the abattoirs at that point. Fecal coliforms (3-198MPN/100ml) were detected in all samples, indicating the presence of other potentially harmful microorganisms. The findings of this study indicate that the water is unsuitable for direct drinking water purposes and stringent water quality control measures should be implemented.


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