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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Sediment management and morphodynamics : The use of erosion models to predict the influence of land use changes on urban impoundments
The use of erosion models to predict the influence of land use changes on urban impoundments
Author : R GILAU(1), PROF C JAMES(2)
The impact of soil loss from urban erosion processes is a major problem confronting decision makers on a national and
local level. One such resource is the Boksburg Lake in the Eastern Service Delivery Region of the Ekurhuleni
Metropolitan Municipality of the Gauteng Province, South Africa.
The purpose of the study was to quantify what impact soil erosion, as a result of changes in land-use, had on the urban
impoundment. There is a close relationship between how land is managed and the impact erosion may have on instream
health. Increased erosion as a result of catchment changes increases the loads of phosphorus introduced into
streams (Croke, 2002) and subsequently increases the occurrence of eutrophication. The management of sediment
levels combined with reduced catchment phosphorus load is viewed as the most viable option in eutrophication
abatement. (This paper will only focus on soil loss modeling done for the study).
Available soil erosion models and methods were compared and the most suited selected for the study. The study used a
modified approach of the Universal Soil Loss Equation and the Soil Loss Estimation Model for Southern Africa, adjusted
for urban conditions. Various simulation models were run and the results indicated that simple application without
considering land uses
Results from five of the models yielded results within 85% confidence, of the measured results. Four of these models are
however not generally proven methods but was only be used as indication. The USLE method utilizing the Vanoni SDR
equation is the preferred method and was applied in subsequent modelling.
The simulation results of the phosphorus loading, although not within a 10% accuracy, relates to the observed loadings
of 2008. By observing a similar trend as the sediment loadings, as a result of the development, it was concluded that the
phosphorus loadings relate to the soil loss models which was related to changes in the catchments as a result of
changes in land usage (imperviousness as indicator).
File Size : 650,609 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Sediment management and morphodynamics
Date Published : 28/08/2015
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