Diurnal fluctuations in shallow groundwater levels and streamflow rates and their interpretation – A review

Abstract. There is a need for an evidence-based approach to identify how best to support development of groundwater for small scale irrigation in sub-Saharan Africa (SSA). We argue that it is important to focus this effort on shallow groundwater resources which are most likely to be used by poor rural communities in SSA. However, it is important to consider constraints, since shallow groundwater resources are likely to be vulnerable to over-exploitation and climatic variability. We examine here the opportunities and constraints and draw upon evidence from Ethiopia. We present a methodology for assessing and interpreting available shallow groundwater resources and argue that participatory monitoring of local water resources is desirable and feasible. We consider possib le models for developing distributed small-scale irrigation and assess its technical feasibility. Because of power limits on water lifting and also because of available technology for well construction, groundwater at depths of 50 m or 60 m cannot be regarded as easily accessible for small-scale irrigation. We therefore adopt a working definition of shallow groundwater as < 20 m depth. This detailed case study in the Dangila woreda in Ethiopia explores the feasibility of exploiting shallow groundwater for small-scale irrigation over a range of rainfall conditions. Variability of rainfall over the study period (9 % to 96 % probability of non-exceedance) does not translate into equivalent variability in groundwater levels and river baseflow. Groundwater levels, monitored by local communities, persist into the dry season to at least the end of December in most shallow wells, indicating that groundwater is available for irrigation use after the cessation of the wet season. Arguments historically put forward against the promotion of groundwater use for agriculture in SSA on the basis that aquifers are unproductive and irrigation will have unacceptable impacts on wetlands and other groundwater-dependent ecosystems appear exaggerated. It would be unwise to generalise from this case study to the whole of SSA, but useful insights into the wider issues are revealed by the case study approach. We believe there is a case for arguing that shallow groundwater in sub-Saharan Africa represents a neglected opportunity for sustainable intensification of small-scale agriculture.

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Groundwater recharge processes in an Asian mega-delta: hydrometric evidence from Bangladesh

Hydrogeology Journal ◽

10.1007/s10040-020-02238-3 ◽

2020 ◽

Vol 28 (8) ◽

pp. 2917-2932

Author(s):

Sara Nowreen ◽

R. G. Taylor ◽

M. Shamsudduha ◽

M. Salehin ◽

A. Zahid ◽

...

Keyword(s):

Groundwater Recharge ◽

Conceptual Models ◽

Shallow Groundwater ◽

Depositional Environments ◽

Series Data ◽

Groundwater Depletion ◽

Bengal Basin ◽

River Channels ◽

Groundwater Levels ◽

Pleistocene Aquifer

AbstractGroundwater is used intensively in Asian mega-deltas yet the processes by which groundwater is replenished in these deltaic systems remain inadequately understood. Drawing insight from hourly monitoring of groundwater levels and rainfall in two contrasting settings, comprising permeable surficial deposits of Holocene age and Plio-Pleistocene terrace deposits, together with longer-term, lower-frequency records of groundwater levels, river stage, and rainfall from the Bengal Basin, conceptual models of recharge processes in these two depositional environments are developed. The representivity of these conceptual models across the Bengal Basin in Bangladesh is explored by way of statistical cluster analysis of groundwater-level time series data. Observational records reveal that both diffuse and focused recharge processes occur in Holocene deposits, whereas recharge in Plio-Pleistocene deposits is dominated by indirect leakage from river channels where incision has enabled a direct hydraulic connection between river channels and the Plio-Pleistocene aquifer underlying surficial clays. Seasonal cycles of recharge and discharge including the onset of dry-season groundwater-fed irrigation are well characterised by compiled observational records. Groundwater depletion, evident from declining groundwater levels with a diminished seasonality, is pronounced in Plio-Pleistocene environments where direct recharge is inhibited by the surficial clays. In contrast, intensive shallow groundwater abstraction in Holocene environments can enhance direct and indirect recharge via a more permeable surface geology. The vital contributions of indirect recharge of shallow groundwater identified in both depositional settings in the Bengal Basin highlight the critical limitation of using models that exclude this process in the estimation of groundwater recharge in Asian mega-deltas.

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Spatial variability of shallow groundwater level in the Northern Kathmandu Valley

Journal of Nepal Geological Society ◽

10.3126/jngs.v55i1.22788 ◽

2018 ◽

Vol 55 (1) ◽

pp. 45-54

Author(s):

Manish Shrestha ◽

Naresh Kazi Tamrakar

Keyword(s):

Groundwater Level ◽

Shallow Groundwater ◽

Soil Surface ◽

Northern Region ◽

Dry Season ◽

Kathmandu Valley ◽

Wet Season ◽

Geological Material ◽

Groundwater Levels ◽

Shallow Groundwater Level

Groundwater is the water which is present in pore spaces and in the fractures of the geological materials beneath earth surface. Water is incompressible substance and presence of small amount of water in geological material modifies the behavior of geological material under stresses. Determination of engineering behavior of the geological material is almost impossible skipping the role of water. The objective of this study was to map and evaluate shallow groundwater level of the northern Kathmandu Valley covering main rivers such as the Bagmati River, Bishnumati River, Dhobi Khola and the Manahara Khola. These rivers flow from the North to the South across the sand rich sediment zone. Static groundwater levels of 239 wells were measured from different locations of the study area in April/March 2017 (Dry Season) and in August 2017 (Wet Season). Shallow groundwater level was measured from soil surface to water level using well water depth logger (Qin and Li, 1998). The result showed that groundwater level ranged from 0.6 m to 12.5 m in dry season and 0.1 m to 13 m in wet season. The groundwater level increased by average of 34.68% (n = 235) as compared to that in dry season. Increase in the groundwater level suggests recharge of groundwater in wet season of the study area. The flow pattern of groundwater levels from the study shows flow of shallow groundwater towards the major rivers of that particular river watershed. As a consequence, seepage flow and piping erosion is likely along the riverbank slopes. Increase in recharge of groundwater during wet season exhibits that the northern region of the Kathmandu Valley is potential for groundwater recharge and can be used to manage water for the dry period.

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Modelling the response of shallow groundwater levels to combined climate and water-diversion scenarios in Beijing-Tianjin-Hebei Plain, China

Hydrogeology Journal ◽

10.1007/s10040-017-1574-4 ◽

2017 ◽

Vol 25 (6) ◽

pp. 1733-1744 ◽

Cited By ~ 8

Author(s):

Xue Li ◽

Si-Yuan Ye ◽

Ai-Hua Wei ◽

Peng-Peng Zhou ◽

Li-Heng Wang

Keyword(s):

Shallow Groundwater ◽

Water Diversion ◽

Groundwater Levels ◽

Hebei Plain

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Shallow groundwater dynamics in smectite dominated clay on the Liverpool Plains of New South Wales

Soil Research ◽

10.1071/sr00002 ◽

2001 ◽

Vol 39 (2) ◽

pp. 203 ◽

Cited By ~ 11

Author(s):

W. Timms ◽

R. I. Acworth ◽

D. Berhane

Keyword(s):

New South ◽

Regional Scale ◽

New South Wales ◽

Shallow Groundwater ◽

Important Indicator ◽

Groundwater Levels ◽

South Wales ◽

Aquifer Systems ◽

North Eastern ◽

Shallow Groundwater System

Dynamic shallow (<5 m) groundwater levels are an important indicator of water and salt fluxes in smectite-dominated clay on the Liverpool Plains in north-eastern New South Wales. Previous hydrogeological assessments of shallow groundwater related salinity risk have focused on regional scale distribution and interaction with rising pressure levels in confined aquifer systems. In this study, groundwater levels over a 7-year period for the saline Yarramanbah subcatchment are presented, along with data from 60 new and existing shallow piezometers and precise elevation surveying and intensive automated monitoring at selected sites. The shallow groundwater system is shown to respond to recharge; however, over the medium-term it is in hydrologic balance, with no evidence of increased water storage. A proportion of recharge is lost by discharge into deeply incised surface channels. Groundwater salinity in the banks of Warrah Creek indicate that flushing of salts from clay is related to increased flux of fresh water. Concern exists that there may be increased salt export from the catchment. If this is in fact occurring while the plains are in hydrologic equilibrium, then increased salt fluxes must be related to factors other than rising groundwater levels.

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Evaluation of the saturated–unsaturated groundwater conditions of a thickened tailings deposit

Canadian Geotechnical Journal ◽

10.1139/t93-091 ◽

1993 ◽

Vol 30 (6) ◽

pp. 935-946 ◽

Cited By ~ 15

Author(s):

S. Lee Barbour ◽

G. Ward Wilson ◽

L.C. St-Arnaud

Keyword(s):

Atmospheric Oxygen ◽

Shallow Groundwater ◽

Groundwater Levels ◽

Acid Generation ◽

Zinc Mine ◽

Retention Characteristics ◽

Copper Zinc ◽

Rate Of Evaporation ◽

Thickened Tailings

The method of thickened tailings disposal has been in use at an active copper–zinc mine near Timmins, Ontario, for approximately 25 years. The thickened tailings deposit that has been formed was investigated. Field and laboratory tests were conducted to determine particle-size distribution at various horizontal locations, in situ values of hydraulic conductivity, moisture-retention characteristics, groundwater levels, and in situ water contents. The results of the investigation show that the thickened tailings deposit is relatively homogeneous. Shallow groundwater levels were also observed to follow the gently sloping topography of the tailings surface. Upward-seepage analyses were conducted for various steady-state evaporative fluxes. The analyses showed the tailings tend to maintain saturated conditions for the highest potential rate of evaporation observed. The ability of the tailings to maintain saturation is attributed to the shallow groundwater levels and the high air-entry value of the tailings. The tendency to saturated conditions at the tailings surface is a positive result. Saturated conditions in the tailings minimize the diffusion of atmospheric oxygen into the tailings. This aids in the prevention of acid generation in these tailings, which have the potential to oxidize and produce acid drainage. Key words : tailings, saturation, evaporation, acid generation.

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Seasonal variation in the microbial quality of shallow groundwater in the Kathmandu Valley, Nepal

Water Science & Technology Water Supply ◽

10.2166/ws.2013.213 ◽

2013 ◽

Vol 14 (3) ◽

pp. 390-397 ◽

Cited By ~ 12

Author(s):

Sadhana Shrestha ◽

Takashi Nakamura ◽

Rabin Malla ◽

Kei Nishida

Keyword(s):

Groundwater Level ◽

Seasonal Variations ◽

Shallow Groundwater ◽

Dry Season ◽

Kathmandu Valley ◽

Microbial Quality ◽

Wet Season ◽

Groundwater Levels ◽

E Coli

To develop effective groundwater pollution control strategies for the Kathmandu Valley, Nepal, seasonal variations in microbial quality and their underlying mechanisms must be understood. However, to date, there are no studies that address these topics. In this study, groundwater samples from dug wells were collected during the dry and wet seasons from 2009 to 2012, and Escherichia coli (E. coli) and total coliforms were analysed. Three wells were monitored each month for a year. Microbial concentrations in shallow groundwater were significantly higher during the wet season than during the dry season. Analyses of rainfall and E. coli concentrations in different seasons indicated that a high level of faecal material infiltration during the rainy season may have caused the seasonal variations in microbial quality. A moderate to strong relationship between E. coli concentrations and groundwater level suggested that the rise in groundwater levels during the wet season may be another reason for this variation. This long time-scale survey detected a significant decline in the microbial quality of shallow groundwater during the wet season as compared with the dry season. We propose that the infiltration of contaminants and change in groundwater level are the two probable mechanisms for the observed seasonal differences.

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Potential of Shallow Groundwater for Household Level Irrigation Practices in Tahtay Koraro Woreda, Tigray, Northern Ethiopia

Momona Ethiopian Journal of Science ◽

10.4314/mejs.v13i1.3 ◽

2021 ◽

Vol 13 (1) ◽

pp. 43-66

Author(s):

Ermias Hagos ◽

Amare Girmay ◽

Tesfamichael Gebreyohannes

Keyword(s):

Groundwater Recharge ◽

Large Scale ◽

Potential Evapotranspiration ◽

Shallow Groundwater ◽

Northern Ethiopia ◽

Groundwater Abstraction ◽

Groundwater Levels ◽

Household Level ◽

Average Value ◽

Dug Wells

This paper deals with the results of a pilot study conducted to estimate the shallow groundwater resource potential and irrigation capacity at the household level in Tahtay Koraro Woreda, northwestern zone of Tigray, Ethiopia. The potential evapotranspiration and actual evapotranspiration of the study area are estimated to be 1484 mm/year and 814 mm/year respectively. The runoff is approximately calculated to be 280 mm/year and the annual groundwater recharge is estimated to be 29 mm/year. The total annual groundwater abstraction for human, livestock, and irrigation is estimated to be 25 mm/year. It should be noted that the groundwater recharge rate is expected to remain constant while the total annual groundwater discharge is expected to increase from year to year. This relation when projected over a long period may result in a negative groundwater budget which can result in depletion of groundwater (lowering of groundwater levels), reduced baseflow to streams, and deterioration of water quality. The computed values for hydraulic conductivity of the aquifers range from 1.63 m/day to 7.27 m/day with an average value of 4.9 m/day and transmissivity from 48.9 m2/day to 218.1 m2/day with an average value of 147.14 m2/day. The aquifers in the highly weathered basalt and highly weathered siltstone – sandstone intercalation have transmissivity values ranging from 99 m2/day to 218.1 m2/day with an average value of 157 m2/day and are grouped into the moderate potentiality aquifers category. The aquifers in the slightly weathered and fractured metavolcanics grouped under low potentiality based on the lower transmissivity values (<50 m2/day). The study area has low to moderate groundwater potentiality, hence, large-scale groundwater pumping is not possible. Therefore, the current activity of using hand dug wells for household-level irrigation is the best way of using groundwater for irrigation and other uses as well. Increasing the depth of the existing hand dug wells that are constructed in highly weathered basalt and highly weathered siltstone – sandstone intercalation can also enhance the yield of the hand dug wells. It is recommended to use water-saving irrigation technologies rather than increasing the number of wells. This will also help in increasing the irrigation area. Groundwater recharge enhancement structures such as trenches, percolation ponds, and check dams be constructed in scientifically selected localities to further enhance the groundwater potential.

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Soil CO2 and CH4 concentration dynamics and their relationships with soil physicochemical properties, soil enzyme activity, and root biomass under shallow groundwater level

10.22541/au.160562653.39881928/v1 ◽

2020 ◽

Author(s):

Wenchao Zhang ◽

Xinguo Zhou ◽

Jianqiang Zhu ◽

Fahu Li

Keyword(s):

Winter Wheat ◽

Physicochemical Properties ◽

Root Biomass ◽

Shallow Groundwater ◽

Enzymatic Activities ◽

Groundwater Depth ◽

Soil Co2 ◽

Total N ◽

Groundwater Levels ◽

Ch4 Concentration

Soil CO2 and CH4 concentrations are crucial determinants of crop physiology and soil environment. This study aimed to investigate the dynamics of soil CO2 and CH4 concentrations and their correlations with soil nutrient content, enzymatic activities and root biomass at shallow groundwater levels. Lysimeter experiments were conducted at five groundwater depths (20, 40, 50, 60, and 80 cm) and three fertilizer application rates (low, 75%; normal, 100%; high, 125%). Soil CO2 and CH4 concentrations, physicochemical properties, and enzymatic activities were determined in the three growth stages of winter wheat crop, and plant biomass was measured post-harvest. Groundwater depth significantly (P ≤ 0.001) affected CO2 and CH4 concentrations and root parameters, and their critical values appeared at the groundwater depth of 50–60 cm. Soil water content presented quadratic function relation with CO2 concentration, and exhibited the linear correlation with CH4 concentration. As an aerobic respiration product, soil CO2 concentration showed significant positive correlations with organic matter and total N levels, urease, phosphatase and sucrase activities, and root biomass in winter wheat. Soil CH4 concentration depending on anaerobic microbial activity showed significant correlations with soil nutrients, such as soil organic matter, total N, and available K. Fertilization significantly impacted root parameters (P ≤ 0.001) and shoot biomass (P ≤ 0.05) instead of CO2 and CH4 concentrations. In contrast, groundwater depth emerged as a crucial factor as it affected soil physicochemical properties, soil enzymatic activities, root respiration, and winter wheat growth at shallow groundwater levels.

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Mapping the Distribution of Shallow Groundwater Occurrences Using Remote Sensing-Based Statistical Modeling over Southwest Saudi Arabia

Remote Sensing ◽

10.3390/rs12091361 ◽

2020 ◽

Vol 12 (9) ◽

pp. 1361 ◽

Cited By ~ 3

Author(s):

Fahad Alshehri ◽

Mohamed Sultan ◽

Sita Karki ◽

Essam Alwagdani ◽

Saleh Alsefry ◽

...

Keyword(s):

Remote Sensing ◽

Saudi Arabia ◽

Brightness Temperature ◽

Field Data ◽

Shallow Groundwater ◽

Remote Sensing Data ◽

Data Sets ◽

Backscatter Coefficient ◽

Groundwater Levels ◽

Sensing Data

Identifying shallow (near-surface) groundwater in arid and hyper-arid areas has significant societal benefits, yet it is a costly operation when traditional methods (geophysics and drilling) are applied over large domains. In this study, we developed and successfully applied methodologies that rely heavily on readily available temporal, visible, and near-infrared radar and thermal remote sensing data sets and field data, as well as statistical approaches to map the distribution of shallow (1–5 m deep) groundwater occurrences in Al Qunfudah Province, Saudi Arabia, and to identify the factors controlling their development. A four-fold approach was adopted: (1) constructing a digital database to host relevant geologic, hydrogeologic, topographic, land use, climatic, and remote sensing data sets, (2) identifying the distribution of areas characterized by shallow groundwater levels, (3) developing conceptual and statistical models to map the distribution of shallow groundwater occurrences, and (4) constructing an artificial neural network (ANN) and multivariate regression (MR) models to map the distribution of shallow groundwater, test the models over areas of known depth to groundwater (area of Al Qunfudah city and surroundings: 294 km2), and apply the better of the two models to map the shallow groundwater occurrences across the entire Al Qunfudah Province (area: 4680 km2). Findings include: (1) high performance for the ANN (92%) and MR (88%) models in predicting the distribution of shallow groundwater using temporal-derived remote sensing products (e.g., normalized difference vegetation index (NDVI), radar backscatter coefficient, precipitation, and brightness temperature) and field data (depth to water table), (2) areas witnessing shallow groundwater levels show high NDVI (mean and standard deviation (STD)), radar backscatter coefficient values (mean and STD), and low brightness temperature (mean and STD) compared to their surroundings, (3) correlations of temporal groundwater levels and satellite-based precipitation suggest that the observed (2017–2019) rise in groundwater levels is related to an increase in precipitation in these years compared to the previous three years (2014–2016), and (4) the adopted methodologies are reliable, cost-effective, and could potentially be applied to identify shallow groundwater along the Red Sea Hills and in similar settings worldwide.

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