Impact of rainfall events on suspended sediment load and water quality and links to sediment management in Dzindi River Catchment

MESHWR === Department of Hydrology and Water Resources Management === This research was aimed at determining the impact of rainfall events on suspended sediment concentration (SSC) and water quality and links to sediment management in Dzindi River Catchment, Limpopo Province. Rainfall events of diff...

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Main Author: Nemapate, Muthuhadini
Other Authors: Odiyo, J. O.
Format: Others
Language:en
Published: 2017
Subjects:
Online Access:http://hdl.handle.net/11602/890
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spelling ndltd-netd.ac.za-oai-union.ndltd.org-univen-oai-univendspace.univen.ac.za-11602-8902020-05-07T03:17:20Z Impact of rainfall events on suspended sediment load and water quality and links to sediment management in Dzindi River Catchment Nemapate, Muthuhadini Odiyo, J. O. Makungo, R. Rainfall Sediment Water quality Sediment management MESHWR Department of Hydrology and Water Resources Management This research was aimed at determining the impact of rainfall events on suspended sediment concentration (SSC) and water quality and links to sediment management in Dzindi River Catchment, Limpopo Province. Rainfall events of different magnitudes and duration erode different sediment volumes resulting in significant variation in sediment loads of receiving water bodies. This affects the water quality of such water bodies. Water samples for water quality and suspended sediment measurements were collected after each rainfall event for periods of six and five months, respectively, in two consecutive rainy seasons. The periods were from October 2012 to March 2013 and December 2013 to April 2014. The samples were collected from selected cross-sections at four sites along Dzindi River. Physical water quality parameters or water quality indicators (pH, Electrical conductivity (EC) and turbidity) were measured with multi 340i/set multimeter and Orion Aqua Fast II turbidity meter, as they are the indicators of the overall status of the water quality. Suspended sediment concentration (SSC) for each sample was measured using evaporation method. SSC at each cross section was computed using the mean discharge-weighted formula. Field survey was undertaken to identify land use activities that promote erosion and hence sedimentation. The relationship between SSC and rainfall magnitude was determined using sediment rating curves. Water quality and sedimentation status at each cross-section together with the information from the GIS map aided in identifying and recommending the best sediment management strategies for different sites in the study area. pH values for October 2012 to March 2013 and December 2013 to April 2014 were both higher in the downstream site of the river catchment, which is Manamani site. Lowest pH was found in the upstream and mid-stream sites, which were Dzindi water treatment works (DWTW) and Tshisaulu, respectively. Tshisaulu had highest EC value and Lwandani had lowest value, respectively, for the period of October 2012 to March 2013. DWTW had the highest EC value and Tshisaulu had the lowest EC value, respectively, for the period of December 2013 to April 2014. Manamani had high turbidity value and Lwandani had low turbidity value for October 2012 to March 2013. Turbidity for DWTW for the period of December 2013 to April 2014 was the highest and Tshisaulu had the lowest turbidity value. Sediment rating curves for DWTW, Tshisaulu and Manamani, respectively, had coefficient of determination (R2) values of 0.185, 0.53 and 0.99, respectively. Different sediment management strategies, including slope and bank protection and minimum and mulch tillage, were recommended based on topography and land use activities and these strategies can prevent soil erosion and minimize transport of sediments into the river. 2017-10-23T05:45:56Z 2017-10-23T05:45:56Z 2017-09-18 Dissertation http://hdl.handle.net/11602/890 en University of Venda 1 online resource (xi, 89 leaves : color illustrations, color maps
collection NDLTD
language en
format Others
sources NDLTD
topic Rainfall
Sediment
Water quality
Sediment management
spellingShingle Rainfall
Sediment
Water quality
Sediment management
Nemapate, Muthuhadini
Impact of rainfall events on suspended sediment load and water quality and links to sediment management in Dzindi River Catchment
description MESHWR === Department of Hydrology and Water Resources Management === This research was aimed at determining the impact of rainfall events on suspended sediment concentration (SSC) and water quality and links to sediment management in Dzindi River Catchment, Limpopo Province. Rainfall events of different magnitudes and duration erode different sediment volumes resulting in significant variation in sediment loads of receiving water bodies. This affects the water quality of such water bodies. Water samples for water quality and suspended sediment measurements were collected after each rainfall event for periods of six and five months, respectively, in two consecutive rainy seasons. The periods were from October 2012 to March 2013 and December 2013 to April 2014. The samples were collected from selected cross-sections at four sites along Dzindi River. Physical water quality parameters or water quality indicators (pH, Electrical conductivity (EC) and turbidity) were measured with multi 340i/set multimeter and Orion Aqua Fast II turbidity meter, as they are the indicators of the overall status of the water quality. Suspended sediment concentration (SSC) for each sample was measured using evaporation method. SSC at each cross section was computed using the mean discharge-weighted formula. Field survey was undertaken to identify land use activities that promote erosion and hence sedimentation. The relationship between SSC and rainfall magnitude was determined using sediment rating curves. Water quality and sedimentation status at each cross-section together with the information from the GIS map aided in identifying and recommending the best sediment management strategies for different sites in the study area. pH values for October 2012 to March 2013 and December 2013 to April 2014 were both higher in the downstream site of the river catchment, which is Manamani site. Lowest pH was found in the upstream and mid-stream sites, which were Dzindi water treatment works (DWTW) and Tshisaulu, respectively. Tshisaulu had highest EC value and Lwandani had lowest value, respectively, for the period of October 2012 to March 2013. DWTW had the highest EC value and Tshisaulu had the lowest EC value, respectively, for the period of December 2013 to April 2014. Manamani had high turbidity value and Lwandani had low turbidity value for October 2012 to March 2013. Turbidity for DWTW for the period of December 2013 to April 2014 was the highest and Tshisaulu had the lowest turbidity value. Sediment rating curves for DWTW, Tshisaulu and Manamani, respectively, had coefficient of determination (R2) values of 0.185, 0.53 and 0.99, respectively. Different sediment management strategies, including slope and bank protection and minimum and mulch tillage, were recommended based on topography and land use activities and these strategies can prevent soil erosion and minimize transport of sediments into the river.
author2 Odiyo, J. O.
author_facet Odiyo, J. O.
Nemapate, Muthuhadini
author Nemapate, Muthuhadini
author_sort Nemapate, Muthuhadini
title Impact of rainfall events on suspended sediment load and water quality and links to sediment management in Dzindi River Catchment
title_short Impact of rainfall events on suspended sediment load and water quality and links to sediment management in Dzindi River Catchment
title_full Impact of rainfall events on suspended sediment load and water quality and links to sediment management in Dzindi River Catchment
title_fullStr Impact of rainfall events on suspended sediment load and water quality and links to sediment management in Dzindi River Catchment
title_full_unstemmed Impact of rainfall events on suspended sediment load and water quality and links to sediment management in Dzindi River Catchment
title_sort impact of rainfall events on suspended sediment load and water quality and links to sediment management in dzindi river catchment
publishDate 2017
url http://hdl.handle.net/11602/890
work_keys_str_mv AT nemapatemuthuhadini impactofrainfalleventsonsuspendedsedimentloadandwaterqualityandlinkstosedimentmanagementindzindirivercatchment
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