Sensitivity of snowmelt runoff modelling to the level of cloud coverage for snow cover extent from daily MODIS product collection 6

Study region: The Balkhab River Basin in northern Afghanistan Study Focus: Snowmelt is a primary water resource in mountainous regions of the world. Remotely sensed snow cover products are useful for obtaining spatial snow information but have unsolved cloud cover issues. Thus, this study demonstrates (1) a spatiotemporal combination approach for reducing cloud cover and improving the accuracy in snow cover extent (SCE) estimation from 2010 to 2018 using the MODIS daily snow cover product version 6 and (2) the sensitivity of snowmelt runoff modelling to SCE inputs with different levels of cloud cover from 2012 to 2014 using a snowmelt runoff model (SRM). New Hydrological Insights for the Region: The average cloud coverages of the original MODIS Aqua and Terra daily products for the study region and period were reduced from 37.66 % and 31.88 % to 25.9 % after the spatial combination and to 14.28 % and 8.94 %, respectively, after the temporal combination. The temporal combination with previous and following days yielded a substantial improvement in cloud removal. The sensitivity of the SRM results to the different levels of clouds clearly depicts the gradual improvement in the simulated snowmelt runoffs with a cloud cover reduction in the SCE input. Interestingly, the SRM performances with the direct SCE input from Aqua or Terra products are degraded in some cases compared to those without SCE input in the SRM. Thus, careful attention is needed when directly applying remotely sensed snow cover products as input variables in snow hydrological modelling. The simulated snowmelt runoffs are improved substantially in the melting season in March-May. The snowmelt runoff peaks in May are due to the temperature increase and are mainly responsible for extreme floods in the arid study region. This study contributes further to agricultural water resource management for crop cultivation during the dry season from June to September and to flood protection during the snowmelt runoff peaks in May with a potential hydraulic engineering solution

Water resource management for improved crop cultivation and productivity with hydraulic engineering solution in arid northern Afghanistan

Abstract This study is presenting a multidisciplinary approach for mitigations of water resources in the irrigation, water supply, energy, and flood protection using hydrological model coupled with multi-criteria decision analysis (MCDA). The study area is originated in the northern Afghanistan with serious water issues. Soil and Water Assessment Tool (SWAT) was adopted for the hydrological modelling. The model was calibrated and validated using monthly streamflow from 2010 to 2018. The current irrigation state of the watershed was revised based on the crop water requirements and land area to address water shortages. The investigations lead to an engineering-based solution (dam construction) to regulate and control the streamflow, especially during winter and flood season. Analytical hierarchy process (AHP) based on expert’s opinions were used to determine suitable dam site locations. Then, the dam was added to the SWAT model for dam’s impact assessment. The dam reservoir capacity (197,900,938 m3), dam storage area (748 ha), dam height (69 m), electricity generation (Ave = 25.4 MW,  Min =16.23 MW, , Max = 66.5 MW), and flood protection ability were estimated. Finally, cost–benefit analysis (CBA) was conducted to ensure the project feasibility. The CBA proves the feasibility and applicability of proposal. The surplus water can address the water shortages with an extra capacity of irrigating 17,180.5 ha or provision of water supply for the Mazar-i-Sharif city (the fourth biggest city in the Afghanistan). These findings can be used as guidance for the decision-makers in the BRB for the future development of water resource management strategies

Conserved Aspartic Acid Residues Lining the Extracellular Loop I of Sodium-coupled Bile Acid Transporter ASBT Interact with Na+ and 7α-OH Moieties on the Ligand Cholestane Skeleton*

Functional contributions of residues Val-99—Ser-126 lining extracellular loop (EL) 1 of the apical sodium-dependent bile acid transporter were determined via cysteine-scanning mutagenesis, thiol modification, and in silico interpretation. Despite membrane expression for all but three constructs (S112C, Y117C, S126C), most EL1 mutants (64%) were inactivated by cysteine mutation, suggesting a functional role during sodium/bile acid co-transport. A negative charge at conserved residues Asp-120 and Asp-122 is required for transport function, whereas neutralization of charge at Asp-124 yields a functionally active transporter. D124A exerts low affinity for common bile acids except deoxycholic acid, which uniquely lacks a 7α-hydroxyl (OH) group. Overall, we conclude that (i) Asp-122 functions as a Na+ sensor, binding one of two co-transported Na+ ions, (ii) Asp-124 interacts with 7α-OH groups of bile acids, and (iii) apolar EL1 residues map to hydrophobic ligand pharmacophore features. Based on these data, we propose a comprehensive mechanistic model involving dynamic salt bridge pairs and hydrogen bonding involving multiple residues to describe sodium-dependent bile acid transporter-mediated bile acid and cation translocation