A study of the factors and processes involved in the sedimentation of Tarbela reservoir, Pakistan

Ahmed, Khawaja Bilal; Sanchez, Martin

doi:10.1007/s12665-010-0578-3

Cited by 24 publications

(20 citation statements)

References 10 publications

(6 reference statements)

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“…Figure 2 presents the seasonal hydroclimatic cycle for these two basins, showing double-peaked (winter and summer) precipitation with inflow peaking in May for Mangla and July for Tarbela. The Tarbela Dam on the main stem of the Indus is one of the largest individual storages in the UIB, crucial for hydropower generation and irrigation supply (Ahmed and Sanchez, 2011). Annual inflows to Tarbela constitute 70 % melt water, of which snowmelt contributes 44 % and glacial melt contribute 26 % (Mukhopadhyay and Khan, 2015).…”

Section: Upper Indus Basinmentioning

confidence: 99%

Seasonal streamflow forecasting in the upper Indus Basin of Pakistan: an assessment of methods

Charles

Wang

Ahmad

et al. 2018

Hydrol. Earth Syst. Sci.

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Abstract. Timely and skilful seasonal streamflow forecasts are used by water managers in many regions of the world for seasonal water allocation outlooks for irrigators, reservoir operations, environmental flow management, water markets and drought response strategies. In Australia, the Bayesian joint probability (BJP) statistical approach has been deployed by the Australian Bureau of Meteorology to provide seasonal streamflow forecasts across the country since 2010. Here we assess the BJP approach, using antecedent conditions and climate indices as predictors, to produce Kharif season (AprilSeptember) streamflow forecasts for inflow to Pakistan's two largest upper Indus Basin (UIB) water supply dams, Tarbela (on the Indus) and Mangla (on the Jhelum). For Mangla, we compare these BJP forecasts to (i) ensemble streamflow predictions (ESPs) from the snowmelt runoff model (SRM) and (ii) a hybrid approach using the BJP with SRM-ESP forecast means as an additional predictor. For Tarbela, we only assess BJP forecasts using antecedent and climate predictors as we did not have access to SRM for this location. Cross validation of the streamflow forecasts shows that the BJP approach using two predictors (March flow and an El Niño Southern Oscillation, ENSO, climate index) provides skilful probabilistic forecasts that are reliable in uncertainty spread for both Mangla and Tarbela. For Mangla, the SRM approach leads to forecasts that exhibit some bias and are unreliable in uncertainty spread, and the hybrid approach does not result in better forecast skill. Skill levels for Kharif (April-September), early Kharif (April-June) and late Kharif (July-September) BJP forecasts vary between the two locations. Forecasts for Mangla show high skill for early Kharif and moderate skill for all Kharif and late Kharif, whereas forecasts for Tarbela also show moderate skill for all Kharif and late Kharif, but low skill for early Kharif. The BJP approach is simple to apply, with small input data requirements and automated calibration and forecast generation. It offers a tool for rapid deployment at many locations across the UIB to provide probabilistic seasonal streamflow forecasts that can inform Pakistan's basin water management.

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Section: Upper Indus Basinmentioning

confidence: 99%

Seasonal streamflow forecasting in the upper Indus Basin of Pakistan: an assessment of methods

Charles

Wang

Ahmad

et al. 2018

Hydrol. Earth Syst. Sci.

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“…Whilst snowmelt is a function of both winter precipitation and summer temperatures, glacier melt is primarily a function of summer temperatures, although glacier melt is also influenced by snow cover (Charles, 2016). (Ahmed and Sanchez, 2011). Annual inflows to Tarbela constitute 70% melt water, of which snowmelt contributes 44% and glacial melts contribute 26% (Mukhopadhyay and Khan, 2015).…”

Section: Upper Indus Basinmentioning

confidence: 99%

Assessment of methods for seasonal streamflow forecasting in the Upper Indus Basin of Pakistan

Charles

Wang

Ahmad

et al. 2017

Preprint

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Abstract. Timely and skilful seasonal streamflow forecasts are used by water managers in many regions of the world for seasonal water allocation outlooks for irrigators, reservoir operations, environmental flow management, water markets and drought response strategies. In Australia, the Bayesian joint probability (BJP) statistical approach has been deployed by the Australian Bureau of Meteorology to provide seasonal streamflow forecasts across the country since 2010. Here we assess the 15 BJP approach, using antecedent conditions and climate indices as predictors, to produce Kharif season (April-September) streamflow forecasts for inflow to Pakistan's two largest Upper Indus Basin (UIB) water supply dams, Tarbela (on the Indus) and Mangla (on the Jhelum). For Mangla, we compare these BJP forecasts to (i) ensemble streamflow predictions (ESP) from the snowmelt runoff model (SRM) and (ii) a hybrid approach using the BJP with SRM-ESP forecast means as an additional predictor. For Tarbela, we only assess BJP forecasts using antecedent and climate predictors as we did not have access to SRM 20 for this location. Cross validation of the streamflow forecasts show that the BJP approach using two predictors (March flow and an ENSO climate index) provides skilful probabilistic forecasts that are reliable in uncertainty spread for both Mangla and Tarbela. For Mangla, the SRM approach leads to forecasts that exhibit some bias and are unreliable in uncertainty spread, and the hybrid approach does not result in better forecast skill. Skill levels for Kharif (April-September), early Kharif (April-June) and late Kharif (July-September) BJP forecasts vary between the two locations. Forecasts for Mangla show high skill for early 25Kharif and moderate skill for all Kharif and late Kharif, whereas forecasts for Tarbela also show moderate skill for all Kharif and late Kharif, but low skill for early Kharif. The BJP approach is simple to apply, with small input data requirements and automated calibration and forecast generation. It offers a tool for rapid deployment at many locations across the UIB to provide probabilistic seasonal streamflow forecasts that can inform Pakistan's basin water management.Hydrol. Earth Syst. Sci. Discuss., https://doi

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“…Examples of river deltas prograding over bedrock basements with slope‐break knickpoints: (a) Tarbela delta, Pakistan (Ahmed & Sanchez, ), channel is steeper upstream of the knickpoint; (b) Rhône delta, France (Boyer et al, ), channel is steeper downstream of the knickpoint. The blue and red lines are subaerial and subaqueous basements, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…The Tarbela delta, a reservoir infilling delta that formed after the Indus River (Pakistan), was dammed in 1976, developed over a basement where the channel is steeper upstream of the knickpoint. The basement is mainly composed of igneous and metamorphic rocks and has undergone significant deformation due to a high degree of tectonic activity (Ahmed & Sanchez, ). Progradation of the delta was faster than expected; in 2006 the delta front reached a point approximately 11 km away from the dam.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Effects of Subaerial and Subaqueous Basement Slopes on Self‐Similar Morphology of Prograding Deltas

Lai

Hsiao

2017

JGR Earth Surface

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Deltas form over basements of various slope configurations. While the morphodynamics of prograding deltas over single‐slope basements have been studied previously, our understanding of delta progradation over segmented basements is still limited. Here we use experimental and analytical approaches to investigate the deltaic morphologies developing over two‐slope basements with unequal subaerial and subaqueous slopes. For each case considered, the scaled profiles of the evolving delta collapse to a single profile for constant water and sediment influxes, allowing us to use the analytical self‐similar profiles to investigate the individual effects of subaerial/subaqueous slopes. Individually varying the subaerial/subaqueous slopes exerts asymmetric effects on the morphologies. Increasing the subaerial slope advances the entire delta; increasing the subaqueous slope advances the upstream boundary of the topset yet causes the downstream boundary to retreat. The delta front exhibits a first‐retreat‐then‐advance migrating trend with increasing subaqueous slope. A decrease in subaerial topset length is always accompanied by an increase in subaqueous volume fraction, no matter which segment is steepened. Applications are presented for estimating shoreline retreat caused by steepening of basement slopes, and estimating subaqueous volume and delta front using the observed topset length. The results may have implications for real‐world delta systems subjected to upstream tectonic uplift and/or downstream subsidence. Both scenarios would exhibit reduced topset lengths, which are indicative of the accompanied increases in subaqueous volume and signal tectonic uplift and/or subsidence that are at play. We highlight herein the importance of geometric controls on partitioning of sediment between subaerial and subaqueous delta components.

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A study of the factors and processes involved in the sedimentation of Tarbela reservoir, Pakistan

Abstract: International audienc

Cited by 24 publications

References 10 publications

Seasonal streamflow forecasting in the upper Indus Basin of Pakistan: an assessment of methods

Seasonal streamflow forecasting in the upper Indus Basin of Pakistan: an assessment of methods

Assessment of methods for seasonal streamflow forecasting in the Upper Indus Basin of Pakistan

Asymmetric Effects of Subaerial and Subaqueous Basement Slopes on Self‐Similar Morphology of Prograding Deltas

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