Almost every year, Bangladesh experiences disasters such as tropical cyclones, storm surges, coastal erosion or floods. Tropical cyclones originate from the North Indian Ocean and often cause devastating flood inundations in Bangladesh. Storm surges of the Bay of Bengal (BOB) are larger compared to other regions of the world for similar cyclones due to amplification by the shallow water depth, huge continental shelf and convergent coastlines. This scenario of inundation for such storm surges in the future when the sea level rise (SLR) occurs due to global warming will be different from the present. The densely populated coastal region of Bangladesh is likely to become more vulnerable in the future due to SLR. Disaster risks can be reduced if storm surges can be predicted well ahead. To assess the possible changes of inundation in the future, a widely used coastal model, Delft3D, has been applied for this BOB region. The model has been validated for the storm surge of three recent devastating cyclones, namely, Sidr, Aila and Roanu in the southern coast of Bangladesh. The validated model has been run to produce inundation maps and statistics for cyclonic storm surges such as Sidr, Aila and Roanu and probable SLR. Three possible SLR boundary conditions are chosen from the business-as-usual climate scenario representative concentration pathway 8.5 with values of 0.5 m (lower limit), 1 m (upper limit) and 1.5 m (extreme case, considering the subsidence and a rapid collapse of the Antarctic ice sheet). It is found that a category 4 cyclone such as cyclone Sidr would inundate 2.6%, 3.67% and 5.84% of the area of the country if the SLR is 0.5, 1 and 1.5 m, which will affect the livelihood of nearly 4.1, 7.0 and 9.1 million people of Bangladesh, respectively. It will also inundate up to 21.0%, 42.1% and 65.1% of the Sundarbans mangrove forest, which will undoubtedly affect the ecology of this unique ecosystem.

This study presents the trends of channel flow against human interventions and proposes an adaptation plan through a public–private Partnership (PPP) model to overcome the existing deteriorating condition of the Halda River. Being the only natural carp breeding ground in Bangladesh, the Halda River is significant for the national economy. However, the river’s destiny is now stricken with infrastructural obstructions, industrial and residual usage exploits, and short-sighted interventions, whereas the impacts of climate change are likely to worsen the scenarios with high salinity intrusion. The unplanned human interventions due to agricultural purposes are continuously obstructing the river flow and demolishing the carp habitats and spawning within the Halda River extremely. Most of the river bends are potential carp breeding grounds along the river stretch, and the low river flow during pre-monsoon is also impacting the sustainability of the aquatic eco-system. To understand the issues behind the endangering Halda River, this study conducted a sustainability analysis through the river planform, stage trend, and frequency analyses. The planform analysis showed the encroachment of the river impacting the river bends, significant for aquaculture over the last three decades, whereas the stage trends showed the low availability water scenario in these four locations of the river stretch. Besides, the frequency analysis reviewed the threshold minimum flow for the survival of the aquatic habitat, showing that the flow during the pre-monsoon is unsuitable and unacceptable for the survival of the fish habitats using Gumbel distribution. Conservation of the Halda River is a national priority due to its unique ecological and commercial importance, and it is expected that the proposed PPP framework will ensure the long-term sustainability of the river ecosystem. This article is analysing the existing situation of the Halda River and proposing a joint effort from government and private organisation through the PPP model for sustainable ecosystem management as well as the economic benefits of the country. Working together, each of the stakeholders will find direct benefits and can be instrumental for the survival of the Halda River.

Climate change impacts hydrologic processes, compelling more regional water budget studies to understand spatiotemporal hydrological extremes. This study investigates the effects of climate...

Understanding flow patterns and developing a stage-discharge relationship is essential for effectively managing and protecting water resources in watersheds. Evidence of streambank erosion at confluences due to high peak flows further highlights the urgency of implementing sustainable management strategies. However, the unavailability of discharge data for sub-watersheds necessitates the use of modeling techniques. This study employed a three-layered Hydrological model VIC to estimate the stage-discharge relationship and analyze flow dynamics. Beaver Creek, a tributary of the Clinch River, and Cox Creek, situated in Knox County, Tennessee, experience seasonal flow fluctuations and sedimentation, which pose significant challenges to stream sustainability. To validate the VIC model, downstream USGS stations were selected to compare model output flow. The VIC model incorporated vegetation, soil, and climate inputs and was calibrated using the efficient Shuffled Complex Evolution Algorithm. The final model outputs demonstrated high performance, with a Nash Sutcliffe efficiency of 0.90 and a linear correlation exceeding 0.87 compared to the USGS downstream stations. The daily fluxes accurately captured flow peaks, demonstrating the model's efficacy. Additionally, the derived stage-discharge relationship provided a power equation with a correlation of 0.76, facilitating further research and analysis. The outcomes of this study hold significant implications for future hydrodynamic modeling efforts, allowing for the observation of flood inundation and wall shear stress at the confluence of Beaver-Cox Creeks.