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Water is a fundamental human right supporting life, health, and livelihoods. Yet water-related issues are ranked among the top five global economic risks (WEF, 2020). About two-thirds (4 billion) of the world's population live with severe water scarcity for at least one month, of which about 48% live in both India and China (Mekonnen et al., 2016). In Côte d'Ivoire, the Bandama River, one of the largest in the country, has struggled to meet expected demand, causing recurrent water and electricity shortages. The city of Bouaké in Côte d'Ivoire and neighboring towns experienced a severe water shortage in 2018 with the drying up of the water supply reservoir (Loka along the Bandama River), affecting 70% of the population causing difficult economic and social conditions. To fully understand this dimension of water scarcity in the Bandama watershed, this study models current water availability using SWAT and assesses the current watershed system in Cote d’Ivoire. Model calibration and validation performances were suboptimal. However, the model gave important information about the dominant process and the critical areas of the watershed. This information guided the development of strategies to build resilience in the water supply system through institutional and stakeholder-driven approaches.

Water is key in climate change adaptation. The impacts of climate change will primarily manifest themselves through water, with changes in the frequency and intensity of extreme hydroclimatic events such as floods and droughts. Understanding climate change influence is crucial for assessing future water availability and developing sustainable management plans. Vulnerability to these changes differs by region and community, geographic location, nature of climate change impacts, and human factors. The Nunavik region in northern Canada is experiencing some of the most rapid changes in climate in the world, with disproportionately large temperature increases, alterations in precipitation regimes, and thawing of permafrost, among others. This investigation aims to evaluate the impact of climate change on water availability in the Umiujaq community (Nunavik) and propose strategies to reduce the effects of these impacts. In order to achieve these goals, a hydrological model of the basin has been developed and calibrated using the Soil and Water Assessment Tool (SWAT), satellite and local data, and the SWAT Calibration and Uncertainty Programs (SWAT-CUP). Due to a lack of data, a model was first developed for the Grande Riviere de la Baleine watershed (Kuujjuarapik) and then transposed to Umiujaq. The hydrological model was successfully calibrated and validated (NSE = 0.81, RSR = 0.43, PBIAS = 5.2: NSE = 0.68, RSR = 0.56, PBIAS = 0.9). Then, the model was forced with Canadian downscaled climate data (CMIP5) under three emission scenarios (RCP 2.6, RCP4.5, and RCP8.5) to develop a quantitative analysis of the future water cycle's evolution. The results showed a slight increase in precipitation with global warming and a considerable reduction in snow content due to the higher temperatures. A faster and easier snow melting would happen yearly, bringing an earlier streamflow peak in the river. In the worst-case scenario (RCP8.5), the peak streamflow will move from June 17 to May 8 (40 days), which could result in lower water availability during the summer. To address these impacts, two strategies were analyzed: increase the storage capacity of the community and resort to an alternative water source, i.e., groundwater. The first one could be a solution in the short term, while the second one would be more reliable in the long term. However, the community is already facing difficulty in providing a reliable water supply throughout the year, so swift and concerted action from both the community and relevant authorities is of the essence in tackling this issue head-on.

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This study proposes a stratified approach of drought severity assessment using multi-layer simulated soil moisture. SWAT (Soil and Water Assessment Tool) models are calibrated for 50 watersheds in the South-Atlantic Gulf region of the Southeastern US and a high-resolution daily soil moisture dataset is obtained at Hydrologic Unit Code (HUC-12) resolution for a period of January 1982 through December 2013. A near real-time hydrologic simulation framework by coupling the calibrated SWAT models with the National Centers for Environmental Prediction (NCEP) coupled forecast system model version 2 (CFSv2) weather data is developed to forecast various water balance components including soil moisture (SM), actual evapotranspiration (ET), potential evapotranspiration ET (PET), and runoff (SURQ) for near-real time drought severity assessment, and drought forecasting for a lead of 9-months. A combination of the surface and total rooting depth soil moisture percentiles proves to be an effective increment over conventional drought assessment approaches in capturing both, transient and long-term drought impacts. The proposed real-time drought monitoring approach shows high accuracy in capturing drought onset and propagation and shows a high degree of similarity with the U.S. Drought Monitor (USDM), the long-term (PDSI, PHDI, SPI-9 and SPI-12), and the short-term (Palmer Z index, SPI-1 and SPI-6) drought indices. / Master of Science / Drought, a recurring and worldwide phenomenon, with spatial and temporal characteristics varying significantly from across globe, lead to long-term and cumulative environmental changes. Often referred to as creeping phenomena, droughts are difficult to predict and constant monitoring is required to capture the signs of the onset of drought. Spatial variability in drought severity requires an understanding of the hydrology of the region and a knowledge of the relationship between drought inducing climatic extremes and other regional or local characteristics which help build, sustain and propagate droughts. In the absence of long-term observed hydrologic variables like soil moisture, evapotranspiration, simulated hydrologic variables serve an important purpose in understanding the impact of drought on various components of the water budget. However, several continental scale, physics-based models, and large scale remote sensing products find themselves restricted in explaining the watershed scale and sub-watershed scale variability in relation to drought. This study provides a high-resolution simulation of hydrological variables for 50 watersheds in the South-Atlantic Gulf region of the Southeastern US. The high resolution hydrologic simulations provide bedrock for retrospective drought simulations and understanding the response of various hydrologic variables of these watersheds to drought. It also aids in understanding the spatial variability in the relationship, and understanding the impact of seasonality and hydroclimatology on drought. The understanding of the interplay of various water budget components at watershed scale is used in developing a reliable seasonal drought forecasting framework based on the forecasted hydrologic variables from SWAT-CFSv2 coupled models for application in real time with a lead time of 9 months.

Yes / Printed participant information about randomised controlled trials is often long, technical and difficult to navigate. Improving information materials is possible through optimisation and user-testing, and may impact on participant understanding and rates of recruitment. Methods: A study within a trial (SWAT) was undertaken within the CASPER trial. Potential CASPER participants were randomised to receive either the standard trial information or revised information that had been optimised through information design and user testing. Results: A total of 11,531 patients were randomised in the SWAT. Rates of recruitment to the CASPER trial were 2.0% in the optimised information group and 1.9% in the standard information group (odds ratio 1.027; 95% CI 0.79 to 1.33; p=0.202). Conclusions: Participant information that had been optimised through information design and user testing did not result in any change to rate of recruitment to the host trial. Registration: ISRCTN ID ISRCTN02202951; registered on 3 June 2009. / UK National Institute of Health Research Health Technology Assessment Programme (project number 08/19/04) / This article is included in the Studies Within A Trial (SWAT) collection (https://f1000research.com/collections/swat)

In the United States, karst ecosystems cover approximately 20 percent of the country and karst aquifers provide 40 percent of the water used for drinking. In karst-influenced watersheds, karst features such as sinkholes and sinking streams act as rapid pathways for carrying water and pollutants into streams and groundwater. Human activities on karst landscapes can present some special problems such as alterations to hydrologic regime, contamination of groundwater, ground subsidence, and damage to cave ecosystems. Modeling a karst-influenced watershed can provide a better understanding of the interactions between surface and ground water and how water quality is affected by human activities. Several models were evaluated to determine their ability to model both discharge and nutrient transport in karst watersheds. The Soil Water Assessment Tool (SWAT) model was found to be appropriate due to its capability to represent almost all of the hydrological processes, its user-friendliness, and its ability to generate most of the parameters from available data. Moreover, SWAT can represent nitrogen transformations and transport processes and calculate nitrogen loadings, which is critical for karst watersheds. While it has been widely used and found to be an appropriate prediction tool, it does not explicitly include the capacity to represent specific features characteristic of karst-influenced basins. Baffaut and Benson (2008) modified the SWAT 2005 code to simulate faster aquifer recharge in karst environments, and this version was further modified here in the SWAT-Karst to represent karst environments at the HRU scale. A new parameter sink allows simulating the hydrology and nitrate transport in a sinkhole representing its unique landuse and soil characteristics, and a new parameter ss partitions nitrate transported with water that is lost from sinking streams. The SWAT-KARST model was used to simulate discharge and nitrogen loadings within the Opequon Creek karst-influenced watershed, located in the Potomac and Shenandoah River basin in Virginia and West Virginia. In the Opequon Creek watershed, SWAT-karst using the HRU to represent sinkholes had a more notable impact in the watershed hydrology than SWAT-B&B using a pond to represent sinkholes. Results of statistical evaluation show that SWAT-karst and the Baffaut and Benson (2008) version performed better than SWAT in predicting streamflow in a karst-influenced watershed. Although SWAT-karst showed almost the same performance as SWAT-B&B, SWAT-karst model offers the flexibility to represent the unique relationship between surface and ground water in karst features in an HRU. Using an HRU to represent sinkholes can depict the associated variability of a karst landscape. The new variables sink and ss provide a mechanism to represent the nutrient transport through sinkholes and sinking streams. Sensitivity analysis showed that SWAT-karst was sensitive to the new parameter sink which can be used for model calibration and to represent water recharge and nutrient transport to aquifers outside the watershed boundary. / Master of Science