Change of lake area in the southeastern part of China's Badain Jaran Sand Sea and its implications for recharge sources

Understanding the relationship between the changes in lake water volume and climate change can provide valuable information to the recharge sources of lake water. This is particularly true in arid areas such as the Badain Jaran Sand Sea, an ecologically sensitive area, where the recharge sources of lakes are heatedly debated. In this study, we determined the areas of 50 lakes （representing 70% of the total permanent lakes in this sand sea） in 1967, 1975, 1990, 2000 and 2010 by analyzing remote-sensing images using image processing and ArGIS software. In general, the total lake area decreased from 1967 to 1990, remained almost unchanged from 1990 to 2000, and increased from 2000 to 2010. Analysis of the relationship between these changes and the contemporaneous changes in annual mean temperature and annual precipitation in the surrounding areas suggests that temperature has significantly affected the lake area, but that the influence of precipitation was minor. These results tend to su- pport the palaeo-water recharge hypothesis for lakes of the Badain Jaran Sand Sea, considering the fact that the distribution and area of lakes are closely related to precipitation and the size of mega-dunes, but the contemporaneous precipitation can hardly balance the lake water.

Refining aquifer heterogeneity and understanding groundwater recharge sources in an intensively exploited agrarian dominated region of the Ganga Plain

Densely populated region of Ganga Plain is facing aquifer vulnerability through waterborne pollutants and groundwater stress due to indiscriminate abstraction,causing environmental and socio-economic instabilities.To address long-term groundwater resilience,it is crucial to understand aquifer heterogeneity and connectivity,groundwater recharge sources,effects of groundwater abstraction etc.In this con-text,present study aims to understand factors responsible for vertical and spatial variability of groundwater chemistry and to identify groundwater recharge sources in an intensively exploited agrarian region of the Ganga Plain.Interpretation of chemometric,statistical,and isotopic analysis categorises the alluvial aquifer into zone 1(G1;ground surface to 100 m)and zone 2(G2;>100 m-210 m).The group G1 samples are characterized by a wide variation in hydrochemical species,noted with pockets of F-and NO3-rich groundwater,and fresh to more evolved water types,while group G2 groundwater is characterized by a sharp increase in freshwater types and limited variation in their isotopic and hydrochemical species.The G1 groundwater chemistry is governed by soil mineralogy,local anthropogenic inputs(SO42-,Cl-,and NO3-),and manifested by multiple recharge sources(local precipitation,river,canal water,pond).The G2 group is dominated by geogenic processes and mainly recharged by the local precipitation.Geospatial signatures confirm more evolved water type for group G1 in northwestern region,while fresh-water type covers the rest of the study area.Fluoride rich groundwater is attributed to sodic water under alkaline conditions and enrichedδ18O values emphasizing role of evaporation in F-mobilization from micas and amphiboles abundant in the soil.The findings provide insight into potential groundwater vulnerability towards inorganic contaminants,and ground water recharge sources.The outcome of this study will help to develop aquifer resilience towards indiscriminate groundwater extraction for agricultural practices and aim towards sustainable management strategies in a similar hydrogeological setting.

The Source of Groundwater Recharge Based on Entropy Theory in the Arid Areas of North China

Objective Any natural system is constantly exchanging material, energy and information with the environment, and all tkese processes follow the basic law of thermodynamics, with no exception of groundwater recharge and discharge process. On the basis of the principle of the first law of thermodynamics, the reverse geochemical simulation method is widely used in the study of groundwater recharge, runoff and drainage process. However, some studies only consider the material conservation in theprocess, but ignore the probability of the transformation.

Optimizing groundwater recharge plan in North China Plain to repair shallow groundwater depression zone, China

The North China Plain is one of the main grain producing areas in China. However, overexploitation has long been unsustainable since the water supply is mainly from groundwater. Since 2014,the South-to-North Water Diversion Project's central route has been charted to the integrated management of water supply and over-exploitation, which has alleviated the problem to a certain extent. Although the Ministry of Water Resources has made many efforts on groundwater recharge since 2018 most of which have been successful, the recharge has not yet been sufficiently focused on the repair of shallow groundwater depression zones. It still needs further optimization. This paper discusses this particular issue,proposes optimized recharge plan and provides the following recommendations:(1) Seven priority target areas are selected for groundwater recharge in alluvial and proluvial fans in the piedmont plain, and the storage capacity is estimated to be 181.00×10~8 m~3;(2) A recharge of 31.18×10~8 m~3/a is required by 2035 to achieve the repair target;(3) It is proposed to increase the recharge of Hutuo River, Dasha River and Tanghe River to 19.00×10~8 m~3/a and to rehabilitate Gaoliqing-Ningbailong Depression Zone;increase the recharge of Fuyang River, Zhanghe River and Anyang River to 7.05×10~8 m~3/a and rehabilitate Handan Feixiang-Guangping Depression Zone;increase the recharge of Luanhe River by 0.56×10~8 m~3/a and restore Tanghai Depression Zone and Luanan-Leting Depression Zone;moderately reduce the amount of water recharged to North Canal and Yongding River to prevent excessive rebound of groundwater;(4) Recharge through well is implemented on a pilot basis in areas of severe urban ground subsidence and coastal saltwater intrusion;(5) An early warning mechanism for groundwater quality risks in recharge areas is established to ensure the safety. The numerical groundwater flow model also proves reasonable groundwater level restoration in the depression zones by 2035.

Recharging method of active medical implant using wearable incoherent light source

A new method for recharging active medical implant（AMI）in vitro based on incoherent light source and results of the simulation experiments are proposed.Firstly,the models of the AMI recharging method based on incoherent light source in vitro are developed,which include the models of an incoherent light source and skin tissue.Secondly,simulation experiments of the incoherent light source of the AMI recharging process in vitro based on the Monte Carlo（MC）method are carried out.Finally,absorbed fractions of different layers and distributions of density along x axis of the tissue model and other important conclusions have been achieved.