Measuring spatial variability of land use associated with hydrological impact in urbanised quaternary catchments using entropy

Ilunga, Masengo; Singh, V. P.

doi:10.4314/wsa.v41i1.7

Cited by 3 publications

(3 citation statements)

References 20 publications

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“…The vast majority of studies on entropy of streamflow/run-off the river have not dealt specifically with uncertainty associated with MAR. Nonetheless, in a recent study a relationship between the change in runoff and entropy has been established [59]. Moreover, the entropy concept has been used to assess uncertainty associated with MAR for QCs in the Upper Vaal catchment, between 1989 and 2004 [46].…”

Section: Entropy and Mean Annual Runoffmentioning

confidence: 99%

Assessing Catchment Resilience Using Entropy Associated with Mean Annual Runoff for the Upper Vaal Catchment in South Africa

Ilunga

2017

Entropy

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Abstract:The importance of the mean annual runoff (MAR)-hydrological variable is paramount for catchment planning, development and management. MAR depicts the amount of uncertainty or chaos (implicitly information content) of the catchment. The uncertainty associated with MAR of quaternary catchments (QCs) in the Upper Vaal catchment of South Africa has been quantified through Shannon entropy. As a result of chaos over a period of time, the hydrological catchment behavior/response in terms of MAR could be characterized by its resilience. Uncertainty (chaos) in QCs was used as a surrogate measure of catchment resilience. MAR data on surface water resources (WR) of South Africa of 1990 (i.e., WR90), 2005 (WR2005) and 2012 (W2012) were used in this study. A linear zoning for catchment resilience in terms of water resources sustainability was defined. Regression models (with high correlation) between the relative changes/variations in MAR data sets and relative changes in entropy were established, for WR2005 and WR2012. These models were compared with similar relationships for WR90 and WR2005, previously reported. The MAR pseudo-elasticity of the uncertainty associated with MAR was derived from regression models to characterize the resilience state of QCs. The MAR pseudo-elasticity values were relatively small to have an acceptable level of catchment resilience in the Upper Vaal catchment. Within the resilience zone, it was also shown that the effect of mean annual evaporation (MAE) was negatively significant on MAR pseudo-elasticity, compared to the effect of mean annual precipitation (MAP), which was positively insignificant.

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Section: Entropy and Mean Annual Runoffmentioning

confidence: 99%

Assessing Catchment Resilience Using Entropy Associated with Mean Annual Runoff for the Upper Vaal Catchment in South Africa

Ilunga

2017

Entropy

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“…To z kolei przynosi zmianę stopnia niepewności wyrażonego entropią Shannona (np. Zang, Singh, 2012;Fan i in., 2013;Wrzesiński, 2013aWrzesiński, , 2016Ilunga, Singh, 2015;Pan i in., 2017). Czynniki naturalne i antropogeniczne mogą wpływać pozytywnie lub negatywnie na wielkość i zmiany odpływu rzecznego.…”

Section: Wstępunclassified

Niepewność reżimu odpływu rzek w Polsce w warunkach ocieplenia klimatu

Wrzesiński,

Brzezińska

2024

Czasopismo Geograficzne

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Obserwowana od końca lat 80. XX w. zmiana klimatu w Polsce polegająca na istotnym wzroście temperatury powietrza prowadzi do zmiany funkcjonowania środowiska hydrologicznego, w tym sposobu zasilania rzek i wysokości oraz rozkładu odpływu w cyklu rocznym. Celem pracy jest przedstawienie przestrzennego zróżnicowania niepewności reżimu odpływu rzek i jej zmian w Polsce w latach 1951–2020 na podstawie miary opartej na teorii entropii informacji Shannona. Ustalono stopień niepewności odpływu w cyklu rocznym w całym wieloleciu 1951–2020 oraz w dwóch podokresach: przed silnym wzrostem temperatury powietrza (1951–1988) i w jego czasie (1988–2020). Po roku 1988 nastąpił wzrost niepewności i wyrównanie rozkładu odpływu rzek w przypadku 86% przekrojów wodowskazowych w dorzeczu Wisły, istotny statystycznie we wschodniej części dorzecza. Natomiast odpływ większości rzek w dorzeczu Odry (61%) wykazał nieistotny statystycznie spadek entropii rozkładu odpływu. Do przyczyn takich zmian należy zaliczyć przestrzenne zróżnicowanie zmian wysokości odpływu i jego struktury w okresie ocieplenia. Entropia rozkładu informująca o sezonowości odpływu może być przydatną miarą charakteryzującą reżim odpływu i jego transformację w warunkach zmiany klimatu. Na zmianę reżimu odpływu najbardziej narażone są rzeki o reżimie niwalnym, zwłaszcza niwalnym silnie wykształconym, oraz reżimach złożonych: niwalno-pluwialnym i pluwialno-niwalnym.

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“…In the light of the above, this study investigates preliminarily, the change in uncertainty of MAR for a given QC with respect to the change in MAR of another (other) QC(s), hence cross MAR elasticity of entropy. Climatic conditions and human activities may cause changes in hydrological variables such as streamflow (runoff) [ 20 , 22 , 23 , 24 , 25 , 26 ], which has been associated with a degree of uncertainty expressed as Shannon entropy, e.g., [ 23 , 25 , 27 , 28 ]. As mentioned earlier, natural climatic conditions [ 7 , 8 , 9 , 11 , 29 , 30 , 31 ] and/or human activities [ 10 ] may influence positively or negatively streamflow elasticity.…”

Section: Introductionmentioning

confidence: 99%

Cross Mean Annual Runoff Pseudo-Elasticity of Entropy for Quaternary Catchments of the Upper Vaal Catchment in South Africa

Ilunga

2018

Entropy

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This study focuses preliminarily on the intra-tertiary catchment (TC) assessment of cross MAR pseudo-elasticity of entropy, which determines the impact of changes in MAR for a quaternary catchment (QC) on the entropy of another (other) QC(s). The TCs of the Upper Vaal catchment were used preliminarily for this assessment and surface water resources (WR) of South Africa of 1990 (WR90), of 2005 (WR2005) and of 2012 (WR2012) data sets were used. The TCs are grouped into three secondary catchments, i.e., downstream of Vaal Dam, upstrream of Vaal dam and Wilge. It is revealed that, there are linkages in terms of mean annual runoff (MAR) between QCs; which could be complements (negative cross elasticity) or substitutes (positive cross elasticity). It is shown that cross MAR pseudo-elasticity can be translated into correlation strength between QC pairs; i.e., high cross elasticity (low catchment resilience) and low cross elasticity (high catchment resilience). Implicitly, catchment resilience is shown to be associated with the risk of vulnerability (or sustainability level) of water resources, in terms of MAR, which is generally low (or high). Besides, for each TC, the dominance (of complements or substitutes) and the global highest cross MAR elasticity are determined. The overall average cross MAR elasticity of QCs for each TC was shown to be in the zone of tolerable entropy, hence the zone of functioning resilience. This could assure that water resources remained fairly sustainable in TCs that form the secondary catchments of the Upper Vaal. Cross MAR pseudo-elasticity concept could be further extended to an intra-secondary catchment assessment.

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Measuring spatial variability of land use associated with hydrological impact in urbanised quaternary catchments using entropy

Cited by 3 publications

References 20 publications

Assessing Catchment Resilience Using Entropy Associated with Mean Annual Runoff for the Upper Vaal Catchment in South Africa

Assessing Catchment Resilience Using Entropy Associated with Mean Annual Runoff for the Upper Vaal Catchment in South Africa

Niepewność reżimu odpływu rzek w Polsce w warunkach ocieplenia klimatu

Cross Mean Annual Runoff Pseudo-Elasticity of Entropy for Quaternary Catchments of the Upper Vaal Catchment in South Africa

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