A hydrological perspective on drought risk-assessment in the Yellow River Basin under future anthropogenic activities.

Since the late 1970s, the Yellow River Basin (YRB) has experienced accelerated land-use/land cover changes (LULCC) and consumptive water use (CWU) that have imposed low-flow regimes. Upon the continuation of these anthropogenic activities in the future, significant hydrological alteration is expected. This study takes a hydrological perspective on drought to project changes in the YRB drought risk under future LULCC and CWU business-as-usual (BAU) scenarios. A combination of seasonal trend forecasting, drought indices, land-use and hydrological modeling techniques was used. Future LULCC is assessed based on two BAU scenarios to explore the patterns of LULCC with (LULCC-BAU1) and without (LULCC-BAU2) the continuation of the Chinese Grain for Green Program. The results indicated that LULCC-BAU2 will increase the risk of mild and moderate droughts, while CWU and LULCC-BAU1 will impose higher risk of severe and extreme events. LULCC-BAU1 is projected to exacerbate the duration and intensity of the agricultural/hydrological droughts. The frequency of hydrological drought under LULCC-BAU1 and CWU scenarios is projected to increase by 43% and 53% during 2021-2050. The future agricultural droughts will likely be more intense and prolonged than meteorological droughts. Hydrological droughts, however, will be characterized by prolonged but less intense drought comparing to the metrological droughts. The meteorological to agricultural drought propagation will likely be driven by LULCC under BAU1, while the meteorological to hydrological drought propagation is controlled by CWU changes.

Natural and anthropogenic influences on the recent droughts in Yellow River Basin, China.

Drought in human-dominated environments cannot be seen as a unidirectional hazard as its characteristics are derived and modified by both natural climate variability and human influences. In this study, we applied an observation-modeling framework to quantify the natural and human controls on drought characteristics based on simulated and observed hydrometeorological data from six sub-catchments of the Yellow River Basin in China. A calibrated Soil and Water Assessment Tool (SWAT) was applied to simulate the naturalized situation, whereas Standardized Precipitation Index, Streamflow Drought Index, and Soil Moisture Deficit Index were used to characterize drought at meteorological, agricultural and hydrological aspects. Furthermore, various statistical tools, i.e., bivariate correlation analysis, heat maps, and linear models based on multiple regression, were applied to find the statistical relationships between drought characteristics and the multiple influencing factors. The results revealed that the duration of precipitation's dry spells was important for agricultural drought duration, whereas hydrological drought severity and duration highly depended on soil moisture. Meteorological to agricultural drought propagation mechanism was primarily affected by land use/land cover change (LULCC), whereas meteorological to hydrological propagation was influenced mostly by direct human activities (DHA). The human modifiers were found to have both positive and negative effects on drought severity and duration. For instance, agricultural practices and afforestation intensified soil moisture drought, while grassland restoration had a positive impact on agricultural drought severity. Deforestation enhanced hydrological drought, while afforestation and grassland restoration had the opposite effect. Hydrological drought severity and duration were largely amplified by DHA but enhanced by irrigation return flow. Spatially, sub-catchments with high urbanization and irrigated cropland were found to have shorter and less severe droughts than those dominated by grassland.

Water scarcity in the Yellow River Basin under future climate change and human activities.

Under global climate change and pressure from human activities, water scarcity is becoming a major concern in the quest for regional sustainable development in the Yellow River Basin (YRB). This study integrates scenarios of climate change and human activities under the Representative Concentration Pathway (RCP4.5 and RCP8.5) with a watershed-scale hydrological model, and uses the Water Use-to-Availability Ratio (WUAR) to study future water scarcity over six sub-catchments in the YRB. It further investigates the relationship between the future water scarcity and hydroclimatic and anthropogenic drivers. The results suggest that the average WUAR under both RCP4.5 and RCP8.5 will likely exceed the water scarcity threshold (WUAR >20%) and will reach up to 39.9 and 44.7%, respectively. The average WUAR for the upstream and downstream sub-catchments will likely range from 23.8 to 51.6% under RCP4.5 and from 25.5% to 73.8% under RCP8.5, indicating moderate to severe and moderate to extreme water scarcity, respectively. Future WUAR correlates negatively (r-value = -0.85) with the streamflow drought index (SDI) in the upstream sub-catchments, i.e., hydrological drought will likely intensify water scarcity. Conversely, WUAR and SDI would be positively correlated (r-value = +0.70) in the downstream sub-catchments, i.e., water scarcity will become severer despite decreasing severity of hydrological drought. Under climate change, water scarcity in these sub-catchments will exhibit high dependency (Kendall τ correlation coefficient = 0.84) on water-use patterns than on water availability. The regression analysis indicates that the WUAR will increase significantly (p < 0.05) with projected woodland, cropland, and buildup areas under RCP4.5. This relationship will become even more significant (p < 0.01) under RCP8.5. This study provides insights into the potential drivers of future water scarcity in the YRB, which is likely to confront water supply crises. The study should help policymaking towards attaining sustainable water management in the basin.

Comparison of artesunate and quinine in the treatment of Sudanese children with severe Plasmodium falciparum malaria.

Sixty-six children presenting to Singa hospital, Sudan with different manifestations of severe Plasmodium falciparum malaria were randomly divided into two well-matched groups (33 in each arm) to receive either intravenous artesunate 2·4 mg/kg at 0, 12, and 24 hours, then daily, or intravenous quinine 20mg/kg initially then 10mg/kg three times a day. There was no significant difference in the fever, parasite clearance, and coma resolution times. Three patients died, one in the artesunate and two in the quinine groups. One patient developed hypoglycaemia following quinine infusion. Thus, artesunate can be used for the treatment of severe falciparum malaria.