Modelling Shallow Groundwater Evaporation Rates from a Large Tank Experiment

AbstractA large tank (1.4 m x 4.0 m x 1.3 m) filled with medium-coarse sand was employed to measure evaporation rates from shallow groundwater at controlled laboratory conditions, to determine drivers and mechanisms. To monitor the groundwater level drawdown 12 piezometers were installed in a semi regular grid and equipped with high precision water level, temperature, and electrical conductivity (EC) probes. In each piezometer, 6 micro sampling ports were installed every 10 cm to capture vertical salinity gradients. Moreover, the soil water content, temperature and EC were measured in the unsaturated zone using TDR probes placed at 5, 20 and 40 cm depth. The monitoring started in February 2020 and lasted for 4 months until the groundwater drawdown became residual. To model the groundwater heads, temperature, and salinity variations SEAWAT 4.0 was employed. The calibrated model was then used to obtain the unknown parameters, such as: maximum evaporation rates (1.5-4.4 mm/d), extinction depth (0.90 m), mineral dissolution (5.0e-9 g/d) and evaporation concentration (0.35 g/L). Despite the drawdown was uniformly distributed, the increase of groundwater salinity was rather uneven, while the temperature increase mimicked the atmospheric temperature increase. The initial groundwater salinity and the small changes in the evaporation rate controlled the evapoconcentration process in groundwater, while the effective porosity was the most sensitive parameter. This study demonstrates that shallow groundwater evaporation from sandy soils can produce homogeneous water table drawdown but appreciable differences in the distribution of groundwater salinity.

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Understanding the Role of Shallow Groundwater in Improving Field Water Productivity in Arid Areas

Water ◽

10.3390/w12123519 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3519

Author(s):

Xiaoyu Gao ◽

Zhongyi Qu ◽

Zailin Huo ◽

Pengcheng Tang ◽

Shuaishuai Qiao

Keyword(s):

Soil Water ◽

Soil Salinity ◽

Water Productivity ◽

Shallow Groundwater ◽

Irrigation Scheduling ◽

Crop Growth ◽

Groundwater Depth ◽

Groundwater Salinity ◽

Arid Areas ◽

Soil Water And Salt

Soil water and salt transport in soil profiles and capillary rise from shallow groundwater are significant seasonal responses that help determine irrigation schedules and agricultural development in arid areas. In this study the Agricultural Water Productivity Model for Shallow Groundwater (AWPM-SG) was modified by adding a soil salinity simulation to precisely describe the soil water and salt cycle, calculating capillary fluxes from shallow groundwater using readily available data, and simulating the effect of soil salinity on crop growth. The model combines an analytical solution of upward flux from groundwater using the Environmental Policy Integrated Climate (EPIC) crop growth model. The modified AWPM-SG was calibrated and validated with a maize field experiment run in 2016 in which predicted soil moisture, soil salinity, groundwater depth, and leaf area index were in agreement with the observations. To investigate the response of the model, various scenarios with varying groundwater depth and groundwater salinity were run. The inhibition of groundwater salinity on crop yield was slightly less than that on crop water use, while the water consumption of maize with a groundwater depth of 1 m is 3% less than that of 2 m, and the yield of maize with groundwater depth of 1 m is only 1% less than that of 2 m, under the groundwater salinity of 2.0 g/L. At the same groundwater depth, the higher the salinity, the greater the corn water productivity, and the smaller the corn irrigation water productivity. Consequently, using modified AWPM-SG in irrigation scheduling will be beneficial to save more water in areas with shallow groundwater.

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Development of key technologies in the electric power industry to achieve the requirements of maintaining the limit of atmospheric temperature increase by 1.5 °C by 2050

2020 International Conference Engineering Technologies and Computer Science (EnT) ◽

10.1109/ent48576.2020.00013 ◽

2020 ◽

Author(s):

Aleksandr Pilipenko

Keyword(s):

Electric Power ◽

Temperature Increase ◽

Electric Power Industry ◽

Atmospheric Temperature ◽

Power Industry ◽

Key Technologies

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Temporal dependence of potentiometric levels and groundwater salinity in alluvial aquifer upon rainfall and evapotranspiration

RBRH ◽

10.1590/2318-0331.0217170059 ◽

2017 ◽

Vol 22 (0) ◽

Author(s):

Robertson Valério de Paiva Fontes Júnior ◽

Abelardo Antônio de Assunção Montenegro

Keyword(s):

Temporal Dynamics ◽

Potential Evapotranspiration ◽

Shallow Groundwater ◽

Temporal Analysis ◽

Alluvial Aquifer ◽

Monthly Precipitation ◽

Groundwater Salinity ◽

Temporal Dependence ◽

Time Pattern ◽

Groundwater Levels

ABSTRACT Rainfall uncertainty and high evapotranspiration rates in the semiarid regions not only play an important impact on surface water scarcity, but interfere on shallow groundwater quantity and quality. The aim of this study was to apply geostatistical methodology to analyze the time dependence of potentiometric levels and groundwater salinity in an intensively monitored alluvial aquifer upon agroclimatological variables, and thus investigate possible monthly and annual correlations. Statistically stable piezometers were considered for the temporal analysis, representing the mean behavior of the whole aquifer. It has been verified that stable piezometers for groundwater levels exhibited temporal dependence of 7 months, similar to the temporal scale of variation for monthly precipitation and potential evapotranspiration, which is consistent to the resulting crossed-semivariogram. Meanwhile, stable piezometers for electrical conductivity showed high uncertainty on temporal dependence scale, which ranged from 3 to 8 months. Thus, rainfall and evapotranspiration alone did not properly explain the temporal dynamics of groundwater salinity. The produced maps successfully identified the long term time pattern of groundwater variation, constituting an important support for water resources evaluation.

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GEOLOGIC INFLUENCES OF SECONDARY MINERAL DISSOLUTION TO THE HYDROGEOCHEMISTRY OF SHALLOW GROUNDWATER DISCHARGING TO URBAN CATCHMENTS WITHIN THE SANTA MONICA MOUNTAINS WATERSHED

10.1130/abs/2016cd-274671 ◽

2016 ◽

Author(s):

Geza I. Demeter ◽

◽

Barry J. Hibbs

Keyword(s):

Shallow Groundwater ◽

Mineral Dissolution ◽

Secondary Mineral ◽

Santa Monica Mountains ◽

Santa Monica ◽

Urban Catchments

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Shallow groundwater chemical evolution, isotopic hyperfiltration, and salt pan formation in a hypersaline endorheic basin: Pilot Valley, Great Basin, USA

Hydrogeology Journal ◽

10.1007/s10040-021-02371-7 ◽

2021 ◽

Author(s):

A. L. Mayo ◽

D. G. Tingey

Keyword(s):

Great Basin ◽

Chemical Evolution ◽

Isotopic Fractionation ◽

Shallow Groundwater ◽

Alluvial Fan ◽

Mineral Dissolution ◽

Driving Mechanism ◽

Evaporative Water ◽

Salt Pan ◽

Endorheic Basin

AbstractEndorheic basin brines are of economic significance as sources of boron, iodine, magnesium, potassium, sodium sulfate, sodium carbonate, and tungsten, and they are a major source of the critical metal lithium. Although evaporation is the primary hypersalinization driver for evaporative water bodies, recent investigations have proposed more novel mechanisms for some subsurface brine. This investigation explores shallow groundwater hypersalinization. The chemical evolution and isotopic fractionation of shallow hypersaline groundwater in the clay-rich arid endorheic basin sediments of Pilot Valley, Great Basin (USA), were investigated. Groundwater evolves from fresh in the mountain bedrock and alluvial fans, to brackish and saline at the alluvial fan–playa interface, and to hypersaline in the upper 12 m of basin sediments. Alluvial fan systems are isolated from each other and have varying groundwater 3H and 14C travel times. Nonevaporative in-situ isotopic fractionation of up to −8‰ in δ18O is attributed to clay sequence hyperfiltration. Groundwater flow-path sulfate and chloride mineral dissolution is the primary driving mechanism for both interface and basin groundwater evolution. Evaporation only impacts the groundwater quality in a small portion of the basin where the groundwater is within ~1 m of the ground surface. Here capillary action carries dissolved soluble salts to the land surface. Episodic flooding redissolves and carries the precipitated salt to the annually flooded salt pan where it accumulates as a salt crust during the dry season. The Pilot Valley model may help explain the buildup accumulative layers of soluble salt that when remobilized becomes subsurface brine.

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The effect of recurrent cyclonic surge events on drinking pond and near-surface groundwater salinities in coastal Bangladesh

10.5194/egusphere-egu21-8962 ◽

2021 ◽

Author(s):

Chi San Tsai ◽

Adrian Butler ◽

Mohammad Hoque

Keyword(s):

Drinking Water ◽

Monsoon Season ◽

Shallow Groundwater ◽

Pond Water ◽

Dry Season ◽

Groundwater Salinity ◽

Negative Effects ◽

Near Surface ◽

Coastal Bangladesh ◽

The Impact

<p>Salinity is a pervasive problem in the coastal low-lying area of the deltas including Bangladesh located in one of the largest delta, Ganges-Brahmaputra-Meghna delta. This delta is susceptible to episodic cyclones since it is nearly every 3 years hit by tropical cyclones in the early monsoonal season (April to June) or the early dry season (October to November). These successive cyclones associated with low-lying reclaimed lands that trigger extensive flooding and result in excess salinity in soil and surface water, which have led to low agricultural productivity. Salinity in drinking water causes negative effects on human health such as cardiovascular disease. A fully coupled surface-subsurface model was used to investigate the impact of the episodic cyclonic surges on the drinking pond and groundwater salinities in the coastal reclaimed lands of Dacope Upazila in southwest Bangladesh. We considered 5 scenarios: a cyclone hit the land in the monsoon season with remediation (clean-up the pond at (1) 7 days, (2) 3 months), a cyclone hit the land in the dry season with remediation (clean-up the pond at (3) 7 days (4) 9 months) and (5) the recurrent intervals of cyclones hit the land every 8 years. The hydrological parameters were calibrated from the fieldwork at DAB site in using in situ field observations. The results show that the episodic cyclones caused inevitable salinity to near-surface groundwater, and in pond water because of post-event delayed emptying of ponds and reversal of hydraulic head gradient. However, rapid remediation after a surge event may help avoid serious salinity in drinking water. The result of scenario 5 indicates that near-surface groundwater salinity progressively developed and move downward over time. The episodic surge events might be one of the reasons that cause shallow groundwater salinity in coastal Bangladesh. This study improves our understanding of salinization processes and how to manage drinking water ponds after a storm surge induced flooding in deltaic coastal settings.</p>

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Hydrochemical Characteristics and Evolution Laws of Shallow Groundwater in Shuangliao City

E3S Web of Conferences ◽

10.1051/e3sconf/202129002014 ◽

2021 ◽

Vol 290 ◽

pp. 02014

Author(s):

Li Xuguang ◽

Zhao YanDai ◽

He Haiyang

Keyword(s):

Flow Direction ◽

Shallow Groundwater ◽

Mineral Dissolution ◽

Hydrochemical Characteristics ◽

The North ◽

Evolution Laws ◽

Groundwater Flow Field ◽

Ecological Improvement ◽

Agriculture Development ◽

Hydrochemical Types

Shuangliao City is an important part of the Xiliaohe Plain, and one of the most important bases of grain production in the north of China. Therefore, it is important to ascertain the hydrochemical characteristics of groundwater and their causes and evolution laws in the Xiliaohe Plain to provide guidance to agriculture development and ecological improvement. After collection of detailed data and identification of the groundwater flow field, we studied the causes and evolution of the identified hydrochemical types by zone with mathematical statistics, correlation analysis, ion proportional coefficient and other methods. The results show that the concentrations of HCO3-, Cl-, and Na+ are relatively high, and these of Ca2+, Mg2+, SO42-, and NO3- are relatively low. The concentration of TDS increases gradually along the flow direction of groundwater, and TDS is positively correlated to the variation in concentration of Cl-, Na+, Mg2+, and SO42-. Along the flow direction of groundwater, the hydrochemistry of shallow groundwater show the evolution law from HCO3-Ca·Mg to HCO3·Cl-Na·Ca and HCO3·Cl-Na·Mg, and then to Cl·HCO3-Na·Mg. The hydrochemical types are formed mainly due to the mineral dissolution and deposition, and reaction of cation exchange and adsorption in the aquifer, and the hydrogeochemical processes include leaching, evaporation and concentration, and mixing.

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Stable Isotope and Hydrochemical Evolution of Groundwater in Mining Area of the Changzhi Basin, Northern China

10.21203/rs.3.rs-823775/v1 ◽

2021 ◽

Author(s):

Chunchao Zhang ◽

Xiangquan Li ◽

Jianfei Ma ◽

Zhenxing Wang ◽

Xinwei Hou

Keyword(s):

Anthropogenic Activities ◽

Groundwater Resources ◽

Shallow Groundwater ◽

Northern China ◽

Mining Area ◽

Mineral Dissolution ◽

Geochemical Processes ◽

Hydrochemical Evolution ◽

Deep Aquifers ◽

Isotopic Analyses

Abstract The Changzhi Basin of China is an economically and ecologically important area with intensive human activities. To foster the sustainable development of groundwater resources and the economy, a total of 117 groundwater samples were collected in shallow and deep aquifers, including 91 2H and 18O isotope samples, to improved understanding of the natural geochemical processes and the impacts of anthropogenic activities on the groundwater chemistry. Synthetical application of the stable isotopes, Piper diagram, Gibbs diagram, ionic ratios and saturation indices to data analysis led to identification of hydrochemical zones for both aquifers from west to east of the basin. Isotopic analyses suggested that the groundwater recharge mainly comes from infiltration of rain water, hydraulic interaction between surface water and shallow groundwater, and lateral recharge from fissure water at the edge of the basin. The predominant natural geochemical processes include mineral dissolution in conjunction with the cation exchange. The excess deuterium method revealed that mineral dissolution contributed 81%–98% to the salinity of shallow groundwater and 84%–98% to the salinity of deep groundwater. Anthropogenic activities are secondary contributions to the hydrochemical evolution with fertilizer application, human waste and sewage discharges causing an increase in NO3-N content and coal mining activities affecting the ion content of Na+, Cl-, SO42-, and HCO3- in the groundwater.

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