ORCID Profile
0000-0003-4243-0781
Current Organisation
International Islamic University, Islamabad
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Publisher: Elsevier BV
Date: 10-2019
Publisher: Copernicus GmbH
Date: 21-03-2023
DOI: 10.5194/NHESS-2023-4
Abstract: Abstract. The impact of drought on environmental flow (EF) in 27 catchments of the Indus basin is studied from 1980–2018 using the Indicators of Hydrologic Alterations (IHA). The standardized Precipitation Evapotranspiration Index (SPEI) was systematically propagated from one catchment to another using principal component analysis (PCA). Threshold regression is used to determine the severity of drought (scenario-1) and month (scenario-2) that trigger low flows in the Indus Basin. The impact of drought on low EFs is quantified using the Range of variability analysis (RVA). The hydrological alteration factor (HAF) is calculated for each catchment in the Indus basin. The results show that most of the catchments are vulnerable to drought during the periods 1984–1986, 1991/1992, 1997 to 2003, 2007 to 2008, 2012 to 2013, and 2017 to 2018. On a higher time scale (SPEI-12), drought is more severe in Lower Indus Basin (LIB) than in the Upper Indus Basin (UIB). IHA pointed out that drought significantly impacts the distribution of environmental flow components, particularly extreme low flow (ELF) and low flow (LF). The magnitude and frequency of the ELF and LF events increase as drought severity increases. The threshold regression provided useful insights indicating that moderate drought can trigger ELF and LF at shorter time scales (SPEI-1 and SPEI-6) in the UIB and Middle Indus Basin (MIB). Conversely, severe and extreme drought triggers ELF and LF at higher time scales (SPEI-12) in LIB. The threshold regression also ided the entire study period (1980–2018) into different time zones (scenario-2), which is useful in quantifying the impact of drought on low EFs using the SPEI coefficient. Higher SPEI coefficients are observed in LIB, indicating high alterations in EF due to drought. HAF showed high alterations in EF in most of the catchments throughout the year except in August and September. The alterations are subject to several factors, including climate change, seasonality of the river flow, land use changes, topography, and anthropogenic activities. Overall, this study provided useful insights for analyzing the effects of drought on EF, especially during low flows.
Publisher: Periodica Polytechnica Budapest University of Technology and Economics
Date: 05-08-2020
DOI: 10.3311/PPCI.15966
Abstract: Pier modification countermeasures are essential as they play a vital role in protecting pier against local scour action. Current study investigates experimentally the scour around vertical pier of octagonal cross section with pier modification such as newly proposed octagonal hooked collar is explored, in steady uniform state, under clear water condition. The results of pier scour without any modification were used as a reference to compute the efficiency of hooked collar provision around octagonal pier. The results show that by increasing the hooked collar width up to 2.5 Wp reduced maximum scour depth significantly. However, the experimental investigation revealed that the best combination to be with a hooked collar width of 2.5 Wp, having sidewall height 0.45 Wp. The best combination minimized around 73.3 % of scour hole depth, compared to octagonal pier without any modification. Using experimental results, a new equation is proposed to predict the scour depth around a bridge pier fitted with hooked collar. Moreover, a relation was developed for maximum scour depth and scour hole volume. Results indicate that the scour hole volume around a bridge pier increases quadratically with maximum scour depth.
Publisher: Elsevier BV
Date: 12-2017
Publisher: Wiley
Date: 07-01-2019
DOI: 10.1002/JOC.5968
Publisher: Copernicus GmbH
Date: 26-10-2017
DOI: 10.5194/HESS-21-5375-2017
Abstract: Abstract. A substantial interpretation of electromagnetic induction (EMI) measurements requires quantifying optimal model parameters and uncertainty of a nonlinear inverse problem. For this purpose, an adaptive Bayesian Markov chain Monte Carlo (MCMC) algorithm is used to assess multi-orientation and multi-offset EMI measurements in an agriculture field with non-saline and saline soil. In MCMC the posterior distribution is computed using Bayes' rule. The electromagnetic forward model based on the full solution of Maxwell's equations was used to simulate the apparent electrical conductivity measured with the configurations of EMI instrument, the CMD Mini-Explorer. Uncertainty in the parameters for the three-layered earth model are investigated by using synthetic data. Our results show that in the scenario of non-saline soil, the parameters of layer thickness as compared to layers electrical conductivity are not very informative and are therefore difficult to resolve. Application of the proposed MCMC-based inversion to field measurements in a drip irrigation system demonstrates that the parameters of the model can be well estimated for the saline soil as compared to the non-saline soil, and provides useful insight about parameter uncertainty for the assessment of the model outputs.
Publisher: EAGE Publications BV
Date: 06-09-2015
Publisher: American Geophysical Union (AGU)
Date: 05-2015
DOI: 10.1002/2014WR016245
Publisher: MDPI AG
Date: 18-09-2015
DOI: 10.3390/RS70912041
Location: United States of America
Location: Pakistan
Location: Saudi Arabia
No related grants have been discovered for Khan Zaib Jadoon.