Abstract: Shendi formation is dominated by Mesozoic sediments and is considered as one of the major sedimentary formations of the Nubian group of formations. It basically consists of upper cretaceous sediments that are mostly fluvially dominated. The Nubian formation overlies basement complex rocks of assumed pre-Cambrian age. In a few places in the Sudan it is overlain by the Hudi Chert formation of lower tertiary age. The vertical sedimentary profiles recorded from Musawwat area including Qurun, Muqur, Maafar and Tumama, in addition to Bajrawiyyah and Umm-Ali area generally indicated a fining upward depositional sequence. The facies description and analysis of rock samples from these areas revealed the presence of eleven major lithofacies types. These included massive conglomerate (Gm), trough cross-bedded conglomerate (Gt), massive sandstone (Sm), trough cross-bedded sandstone (St), planar cross-bedded sandstone (Sp), low-angle horizontally bedded sandstone with pebbles (Sl), Massive sandstone with pebbles (Ss), Ripple Cross-Laminated Sand (Sr), Massive mudstone (Fm), Rootbed mudstone (Fr) and Fine-laminated mudstone (Fl). Trough cross-bedded sandstone (St) represented the highest total succession (56.45%), while Ripple Cross-Laminated Sand (Sr) represented the lowest total succession (0.24%). Based on grain-size analysis, the upper cretaceous strata can be classified as fluvial-dominated units. According to the plot of skewness against sorting, all samples proved to show a river, fluvial-dominated environment origin. The formations may have been formed in meandering rivers or multi-braided channels. In relation to the revealed lithofacies, there is no doubt that these formations were formed mostly in channel environments, and also overbank environments due to channel-breaking or flooding.

Abstract: Measuring discharge in a developing country like Bangladesh is very important to predict flood, land management and sustainable development. In this paper we are interested to investigate discharge estimation and to determine watershed parameters for northeast region of Bangladesh by using a semi-distributed model called Soil and Water Assessment Tool (Arc SWAT) after comparing simulated result with observed data. ArcGIS version 10.3 with extension software SWAT has been used to prepare a hydrological model for Meghna River catchment. For model calibration SWAT_CUP SUFI-2 algorithm has been used. The calibration and validation has been done at Bhairab Bazar station, outlet of Meghna River catchment. The paper also indicates a numerical modeling work performed in order to assess the feasibility of using freely available global weather, topography, and soil and land use datasets to simulate flow of the Meghna River catchment. The performance of the model indicates that such an approach can indeed produce an acceptable results. The NSE and R2 values for statistical evaluation of model efficiency for calibration period 2001-2006 and validation period 2007-2013 are 0.85, 0.88 and 0.76, 0.85 respectively.