scholarly journals Water Quality Control Options in Response to Catchment Urbanization: A Scenario Analysis by SWAT

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1846
Author(s):  
Hong Nguyen ◽  
Friedrich Recknagel ◽  
Wayne Meyer

Urbanization poses a challenge to sustainable catchment management worldwide. This study compares streamflows and nutrient loads in the urbanized Torrens catchment in South Australia at present and future urbanization levels, and addresses possible mitigation of urbanization effects by means of the control measures: river bank stabilization, buffer strip expansion, and wetland construction. A scenario analysis by means of the Soil and Water Assessment Tool (SWAT) based on the anticipated urban population density growth in the Torrens catchment over the next 30 years predicted a remarkable increase of streamflow and Total Phosphorous loads but decreased Total Nitrogen loads. In contrast, minor changes of model outputs were predicted under the present urbanization scenario, i.e. urban area expansion on the grassland. Scenarios of three feasible control measures demonstrated best results for expanding buffer zone to sustain stream water quality. The construction of wetlands along the Torrens River resulted in the reduction of catchment runoff, but only slight decreases in TN and TP loads. Overall, the results of this study suggested that combining the three best management practices by the adaptive development of buffer zones, wetlands and stabilized river banks might help to control efficiently the increased run-off and TP loads by the projected urbanization of the River Torrens catchment.

2007 ◽  
Vol 56 (1) ◽  
pp. 199-205 ◽  
Author(s):  
J.G. Cooke ◽  
R.A. Petch

The overwhelming importance of diffuse sources as a determinant of receiving water quality has been recognised for over 30 years. Significant research and development on techniques for reducing inputs in the riparian zone has resulted in numerous guideline documents being produced. Yet despite this research effort, and the apparently successful transfer of key results to water resource managers, the public perception in New Zealand is that the quality of receiving waters continues to decline. In this paper we examine the veracity of that perception through examination of state-of-the-environment reporting, discussions with water resource managers, and published literature. Using a case study of Lake Taupo, New Zealand as an example, we discuss the difficulties faced by water resource managers in arresting declines in water quality. We compare the reduction in potential nutrient exports possible between ‘non-invasive’ mitigation techniques such as riparian buffer strips, constructed and natural wetlands and source control measures such as the use of nitrification inhibitors and wintering pads. Finally, we look at options available should voluntary measures or best management practices fail to deliver the nutrient reductions that are necessary to maintain lake water quality.


2013 ◽  
Vol 64 (5) ◽  
pp. 401 ◽  
Author(s):  
Robert J. Wilcock ◽  
Ross M. Monaghan ◽  
John M. Quinn ◽  
M. S. Srinivasan ◽  
David J. Houlbrooke ◽  
...  

Five streams in catchments with pastoral dairy farming as the dominant land use were monitored for periods of 7–16 years to detect changes in response to adoption of best management practices (BMPs). Stream water quality was degraded at the start with respect to N, P, suspended solids (SS) and E. coli concentrations, and was typical of catchments with intensive pastoral agriculture land use. Trend analysis showed a decrease in SS concentration for all streams, generally increasing water clarity, and lower E. coli concentrations in three of the streams. These are attributed to improved stream fencing (cattle exclusion) and greater use of irrigation for treated effluent disposal with less reliance on pond systems discharging to streams. Linkages between water quality and farm actions based on survey data were used to develop BMPs that were discussed at stakeholder workshops. Generic and specific BMPs were developed for the five catchments. The 3–7 year periodicity of major climate cycles, as well as market forces and a slow rate of farmer adoption of simple BMPs mean that monitoring programs in New Zealand need to be much longer than 10 years to detect changes caused by farmer actions. Long-term monitoring is also needed to detect responses to newly legislated requirements for improved water quality.


2006 ◽  
Vol 14 (1) ◽  
pp. 59-87 ◽  
Author(s):  
J C Croke ◽  
P B Hairsine

The opening or removal of forest canopies during harvesting or land clearing results in a predictable sequence of responses, the descriptions of which appear remarkably similar around the world. Such activities are now widely acknowledged to have adverse impacts upon water quality and in-stream ecology. Sediment delivery, therefore, encapsulates the dominant process by which water resources are impacted and the process that can be best managed to limit off-site impacts. This paper is a review of current processes, and perceptions, of sediment delivery in managed forests. We outline the major components of sediment and runoff delivery as they relate specifically to timber harvesting activities. Whilst much existing research has focused upon soil loss as the major component of timber harvesting impacts, this review highlights both the need for, and benefits from, a conceptual advance in our thinking of sediment delivery. We advocate that by managing runoff delivery pathways and the resultant pattern of hydrological connectivity, we can limit the potential adverse effects of forest harvesting on in-stream water quality. Specific attention is given here to the interaction of the forest road and track network with both sediment and runoff delivery. The result is a comprehensive account of how best to manage timber harvesting for both on-site sustainability and off-site water resource protection.Key words: timber harvesting, sediment delivery, road network, connectivity, best management practices (BMPs).


Author(s):  
Félicien Majoro ◽  
Umaru Garba Wali ◽  
Omar Munyaneza ◽  
François-Xavier Naramabuye ◽  
Concilie Mukamwambali

Soil erosion is one of the main factors causing land degradation. Furthermore, loss of soil nutrients ultimately causes worldwide reduction of agricultural productivity and water quality deterioration. Therefore, soil erosion control measures are required as an aspect of catchment management. The general purpose of this paper review is to make an overview of soil erosion throughout the world in order to highlight required studies on which to be based when proposing appropriate erosion control measures for agricultural fields. Different scientific documents including journal articles, internet materials, conference papers and books were used as research materials to achieve the objectives of the present work. This methodology enabled the researcher to make a synthesis of various researchers’ views on this topic. Principally, this review focused on the effects and remedial measures of soil erosion. The research findings highlighted that soil erosion affects greatly the agricultural land, human properties and aquatic ecosystem. Both on-site and off-site effects are analyzed. Sediment transport in rivers resulted from soil erosion impacts on bridges, hydropower plants, water treatment plants and water bodies such as lakes and water reservoirs. The present review article strongly recommends the followings: (1) Performance improvement of the existing erosion control measures; (2) Promotion of new soil erosion adaptive measures; (3) Farmers trainings on Best Management Practices of soil erosion control and (4) Sensitization of governmental institutions and Non-governmental organizations (NGOs) to be extensively involved in soil erosion management. Keywords: Erosion causes, erosion effects, erosion control measures


SIMULATION ◽  
2011 ◽  
Vol 88 (3) ◽  
pp. 365-380 ◽  
Author(s):  
Margaret W Gitau ◽  
Li-Chi Chiang ◽  
Mohamed Sayeed ◽  
Indrajeet Chaubey

Models are increasingly being used to quantify the effects of best management practices (BMPs) on water quality. While these models offer the ability to study multiple BMP scenarios, and to analyze impacts of various management decisions on watershed response, associated analyses can be very computationally intensive due to a large number of runs needed to fully capture the various uncertainties in the model outputs. There is, thus, the need to develop suitable and efficient techniques to handle such comprehensive model evaluations. We demonstrate a novel approach to accomplish a large number of model runs with Condor, a distributed high-throughput computing framework for model runs with the Soil and Water Assessment Tool (SWAT) model. This application required more than 43,000 runs of the SWAT model to evaluate the impacts of 172 different watershed management decisions combined with weather uncertainty on water quality. The SWAT model was run in the Condor environment implemented on the TeraGrid. This framework significantly reduced the model run time from 2.5 years to 18 days and enabled us to perform comprehensive BMP analyses that may not have been possible with traditional model runs on a few desktop computers. The Condor system can be used effectively to make Monte Carlo analyses of complex watershed models requiring a large number of computational cycles.


Agriculture ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 69
Author(s):  
Jing Zhang ◽  
Peiqi Zhang ◽  
Yongyu Song

Carbonate rocks are widely distributed in southwest China, forming a unique karst landscape. The Lijiang River Basin provides a typical example of an area with concentrated karst. Research on the laws of hydrology and water quality migration in the Lijiang River Basin is important for the management of the water resources of Guilin City and similar areas. In this study, we combined three meteorological data with the soil and water assessment tool (SWAT) model and the hydrological simulation program-Fortran (HSPF) model to simulate the hydrological and water quality processes in the Lijiang River Basin separately. We chose the Nash–Sutcliffe efficiency (NSE) coefficient, coefficient of determination (R2), root mean square error-observations standard deviation ratio (RSR), and mean absolute error (MAE) as the metrics used to evaluate the models. The results, combined with the time-series process lines, indicated that the SWAT model provides a more accurate performance than the HSPF model in streamflow, ammonia nitrogen (NH3-N), and dissolved oxygen (DO) simulations. In addition, we divided the karst and non-karst areas, and we analyzed the differences between them in water balance, sediment transport, and pollution load. We further identified the key source areas of pollution load in the Lijiang River Basin, evaluated the pollution reduction effect of best management practices (BMPs) on surface source pollution, and proposed some pollution control countermeasures. Each scenario, especially returning farmland to forest and creating vegetation buffer zones, reduces the NH3-N and DO pollution load.


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