Lowering Of Groundwater Level Research Articles

Peat subsidence in a tropical rubber plantation during a strong El Niño year

El Niño usually induces peat fires because dry season was prolonged and rainfall was low. This event potentially increases soil CO2 emissions and peat subsidence on tropical peat due to low groundwater level. Despite this, El Niño impacts on peat soil subsidence is understudied in Indonesia. To fill the gap, we measured peat surface elevation to determine peat soil subsidence at monthly basis during dry season, from June to November, in the strong El Niño year of 2015 and the normal year of 2014. A rubber plantation cultivated on peat soil was selected as a representative area for this research. Subsidence (in cm) was determined by calculating the difference in ground elevation between June and November for 2014 and 2015. Measurement was done by inserting three steel pipes vertically until underlying mineral substrate. We found that peat soil subsidence in strong El Niño year was larger than that of normal year. This finding can be further exploited as the baseline information for peatland management under climate change and or in extreme weather.

Water Use of Hybrid Poplar (Populus deltoides Bart. ex Marsh timesP. nigra L. “AF2”) Growing Across Contrasting Site and Groundwater Conditions in Western Slovakia

The water use by short rotation coppices (SRC) has been a focus of ongoing research in the last decades. Nevertheless, investigations that consider site factors and present long-term monitoring of the components of the water balance are rare. This research quantified the tree-based transpiration in the 4th growing season of uncoppiced 1st rotational hybrid poplar stands (Populus deltoides Bart. ex Marsh × P. nigra L. “AF2”) in western Slovakia. The aim of the study was to determine the influence of meteorological and soil-related site conditions on transpiration rates. Three experimental plots were located in the Morava River floodplains, on loamy sand-textured soils with different groundwater accessibilities: higher, low, and fluctuating groundwater level. We measured sap flow (Heat Ratio Method), volumetric water content, matric potential, groundwater level, and meteorological variables throughout the growing season in 2019. The results indicated that transpiration in the three sites was almost constant during that period, which was characterized by distinct conditions. The average cumulative transpiration at the site with a higher groundwater level (1105 mm) was larger than at the site with a lower groundwater level (632 mm) and the site with fluctuating groundwater (863 mm). A principal component analysis (PCA) and correlation analysis identified that the contribution of meteorological and soil-related site variables to transpiration differed among the sites. Soil water availability and groundwater accessibility are critical variables for the water use of poplar SRC. We concluded that the combination of site conditions needs to be reconsidered for the expansion of sustainable short rotation plantations in Europe.

Subsidence Induced by Gas Extraction: A Data Assimilation Framework to Constrain the Driving Rock Compaction Process at Depth

Surface movement can be induced by many human subsurface activities: production of natural gas, geothermal heat extraction, ground water extraction, phreatic groundwater level lowering, storage of natural gas and CO2. In this manuscript, we focus on subsidence caused by gas production. While geological interpretations, seismic campaigns and flow modeling often provide a relatively rich pre-existing knowledge, understanding of the driving mechanisms for production-induced subsidence is still poor and forecasts are often very uncertain. This is related to the multiple poorly constrained models that translate gas production to ground surface displacements. Currently, a biased constraint of these models is inferred by arbitrarily pre-selecting a subset of those. Here, we have devised and deployed an integrated approach of the entire chain of models from the flow simulations to the ground surface displacements which, for the first time, accounts for all our pre-existing knowledge in terms of processes and uncertainties attached to them. More specifically for the transfer between reservoir depletion to compacting volume at depth, four reservoir-rock compaction models are a-priori considered, ranging from linear elastic model to nonlinear time-dependent viscous-type model. After assimilation of the geodetic observations (i.e., the ground-surface displacements) with ensemble-smoother algorithms, we demonstrate that even when all the a-priori known complexities were present in all steps of the modelling chain, the model parameter uncertainties of each model could be reduced. Interestingly we demonstrate that one can discriminate which reservoir-rock compaction model driving subsidence is activated at depth. This identification of the activated compaction model at depth is crucial to build confidence in our subsidence forecasts. The predictive power of the integrated approach is demonstrated with an ensemble of synthetic but complex reservoir flow simulations mimicking all the characteristics and uncertainties representative for real gas fields in the north of the Netherlands.

Deep learning shows declining groundwater levels in Germany until 2100 due to climate change

In this study we investigate how climate change will directly influence the groundwater resources in Germany during the 21st century. We apply a machine learning groundwater level prediction approach based on convolutional neural networks to 118 sites well distributed over Germany to assess the groundwater level development under different RCP scenarios (2.6, 4.5, 8.5). We consider only direct meteorological inputs, while highly uncertain anthropogenic factors such as groundwater extractions are excluded. While less pronounced and fewer significant trends can be found under RCP2.6 and RCP4.5, we detect significantly declining trends of groundwater levels for most of the sites under RCP8.5, revealing a spatial pattern of stronger decreases, especially in the northern and eastern part of Germany, emphasizing already existing decreasing trends in these regions. We can further show an increased variability and longer periods of low groundwater levels during the annual cycle towards the end of the century.

Assessment of snowmelt and groundwater-surface water dynamics in mountains, foothills, and plains regions in northern latitudes

Snowmelt and groundwater-surface water (GW-SW) dynamics are the most dominant controllers of hydrological processes and water availability in northern latitudes, particularly in warm seasons. The dynamics and changes of snowmelt and GW-SW interactions and their interrelationship at the regional scale are poorly understood in regional analyses. To fill this gap, this study implements a process-based hydrological model, using a coupled Soil and Water Assessment Tool (SWAT) and MODFLOW model, to map snowmelt and GW-SW dynamics at regional scales. The primary research questions are “how are GW-SW interactions altered by snowmelt dynamics?” and “what is the effect of climate change on snowmelt and GW-SW dynamics?” We simulated snowmelt and groundwater dynamics across a large watershed encompassing different ecohydrological regions, including mountains, foothills, and plains, analyzing the spatio-temporal relationships between GW-SW interactions and snowmelts in historical (1983–2007) and future (2040–2064) periods. We used an ensemble of five global climate models (GCMs) for future projections based on two emission scenarios (i.e., RCP2.6 and RCP8.5). We also used the Least Absolute Shrinkage and Selection Operator (LASSO) method to examine the effects of snowmelt, evapotranspiration (ET), and rainfall on GW-SW interactions. These analyses are implemented in mountains, foothills, and plains regions in a large snow-dominated watershed in western Canada. Results show that earlier snowmelt is predicted in mountains and foothills regions under climate change scenarios, while less snow accumulation and melt is anticipated in plains region. Future projections of GW-SW interactions show an increase in groundwater discharge to streams in the winter and spring seasons, mainly due to earlier snowmelt in winter and spring in mountains and foothills regions. On the other hand, more surface water loss to groundwater in summer and fall is predicted, which can be caused by the low level of groundwater under future conditions in foothills regions. Correlation analysis between regional snowmelt and GW-SW interactions for historical simulations show a higher correlation (R2= 0.494) in mountains region, compared to very low correlations (R2<0.01) in foothills and plains regions. LASSO results showed that ET was the main control of dynamics of GW-SW interactions in all regions of the study. Snowmelt was the next most important predictor of GW-SW dynamics in the mountains region, while rainfall was more important in the foothills region. Nevertheless, none of the three predictors strongly influenced GW-SW dynamics in the plains region, mainly due to low groundwater levels and a lack of connectivity with the surface water. Overall, it is shown that the eco-hydrogeological and climatic variability of different regions plays an important part in governing GW-SW dynamics.

Modelling the impact of lining and covering irrigation canals on underlying groundwater stores in the Nile Delta, Egypt

AbstractCanal seepage losses can contribute significantly to groundwater aquifers in arid and semi‐arid regions worldwide. In addition, surface water evaporation and evapotranspiration from adjacent riparian vegetation directly affect surface water availability across these regions. This study aims to evaluate interactions between irrigation canals and the Nile Delta groundwater aquifer in Egypt under four operational scenarios: (i) decreased stream flows in the four main diversion canals associated with upper Nile diversions and climate change, (ii) concrete lining of irrigation canals, (iii) combined lining and use of Photo‐Voltaic (PV) Solar Panel covers on canals and (iv) enclosure of the canals in closed conduits. We investigated the effects of these scenarios on regional groundwater supplies and levels using MODFLOW and water budget analyses. Decreased streamflow (scenario 1) resulted in decreased aquifer recharge (from 732 910 to 483 800 m3 day−1) and lower groundwater levels as compared to the base case (present) conditions. Moreover, groundwater flows from the aquifer to the four main canals noticeably increased from 23 176 to 79 364 m3 day−1. Water budget analyses associated with canal lining scenarios (2, 3, &amp; 4) indicated that canal leakage to the aquifer accounted for 146 582, 146 582, and 73 291 m3 day−1 respectively. The changes in canal efficiencies reached 29.3%, 67.1%, 75.3%, and 91.8% while the changes in aquifer recharge efficiencies were 66%, 20%, 20%, and 10% for the four scenarios, respectively. Overall, we found that canals lining is likely the most suitable solution for managing water resources in the Nile Delta. Further aspects to be considered in future studies include the loss of biodiversity along streams embankments due to channel lining.

The option of Roman canal construction by Drusus in the Vecht river area (the Netherlands): a geoarchaeological approach

Abstract This paper presents a geoarcheological study on potential canal subsections present in the Roman-age Vecht branch of the Rhine-Meuse delta (the Netherlands).The first Roman canals in this delta were dug around 12 BC by Drusus, but their location has been the subject of debate since the 16th century, with various hypotheses proposed. Based on actual palaeogeographical knowledge of the Rhine-Meuse delta, the Utrechtse Vecht hypothesis is considered the most plausible. Within the study area, in the northern part of the Vecht system, natural sections of this river may alternate with possible artificial reaches, created at the time of Drusus. Such artificial canals, being part of an otherwise natural channel belt system, can widen and deepen overtime, eroding all or most of the recognizable features associated with their original construction. As study area was chosen a relatively straight section of the Vecht between two former lakes. Two approaches were used. The first approach centred upon mapping channel morphology and recording sediment stratigraphy of the river deposits through detailed auger coring. Results corroborated the hypothesis of an originally straight feature (landform), confirming that it might have started life as a dug course, but not providing preserved archaeological remains of this stage. The second approach was chronological, whereby a programme of 14C dating was undertaken to refine the understanding of the origin and development of this reach of the Vecht, allowing earlier chronological investigations to be further contextualised and reassessed. A significant challenge to understand age control and floodplain evolution is the degradation of the top of the clayey peat that was observed below the levee deposits; this degradation is due to the lowering of groundwater levels and causes the end of peat growth to be dated as older than it actually is. Using new radiocarbon dates we have reconstructed that the Overmeer-Nigtevecht reach of the Vecht between two former lakes started life as a straight channel. We have constrained its age to be closer to the time of Drusus’ activities (early Roman age). Although we have not found in situ remains of Drusus canal(s), these two new insights make the Vecht option, effectuated by a series of short canals, more likely to be the Drusus canal(s).

The Cauê Aquifer on the eastern limb of the Moeda Syncline: characterization, impacts, and flow in the western Iron Quadrangle (Quadrilátero Ferrífero), MG, Brazil

The Cauê Aquifer is an important water supplier to the third largest urban agglomeration in Brazil. The Metropolitan Region of Belo Horizonte is in the Iron Quadrangle, site of intense iron ore mining, requiring large volumes of water and mine dewatering. In this context, we evaluate the regional impact on groundwater level between 2000 and 2019 based on a conceptual hydrogeological flow model on the eastern limb of the Moeda Syncline. This study includes the definition of boundary conditions and aquifer units, the calculation of hydrodynamic parameters, water balance, renewable reserve, and flow analysis. The Cauê, Gandarela, and Moeda aquifers are considered aquifer units, among which the Cauê Aquifer showed the highest hydraulic conductivity (9.45×10-7 m/s on average) as well as the highest recharge rate, with 38.67% rainfall. The average volume pumped was estimated at 41 million m³/year, equivalent to about 150% of the renewable reserve of the Cauê Aquifer, calculated at 27 million m³/year. Underground flow in the area tends southward, and the Cauê Aquifer acts as a water divide, which is less evident in the center of the area, where the greatest impact on groundwater level lowering occurs.

What are the dynamics of hydrometeorological parameters on peatlands during the 2019 extreme dry season?

Peatlands in Indonesia are generally flammable, including peatlands in Kalimantan. The Indonesian government has made efforts to prevent fires on peatlands in Indonesia. One of them is by establishing several stations for measuring hydrometeorological parameters which are managed by the Peat Restoration Agency (BRG). This study utilizes BRG data, especially rainfall and groundwater levels, combined with hotspots data from MODIS satellite measurements during the 2019 extreme dry season at two research locations, namely at BRG stations in Central Kalimantan and West Kalimantan. The objectives of this research is to study the dynamics of these three parameters and find their relationship during the 2019 extreme dry season. To achieve the objectives of this study, an analysis of the time series graphs of these three parameters was carried out during the 2019 extreme dry season. It is hoped that the results of this research will help to prevent severe fires on peatlands, especially in Kalimantan. The results of this study indicate that during this period there was a decrease in rainfall, a decrease in groundwater level, and the emergence of a large number of hotspots. It can be concluded that the hotspots that appear are closely related to the low groundwater level due to low rainfall.

Hydrogeochemical and Characteristics of Groundwater in Teluk Nilap Area, Rokan Hilir, Riau

Groundwater plays important role as the main water resource for human needs. The vulnerability of groundwater to contaminants both naturally and by human activities can be not avoided as a trigger for groundwater quality degradation. Hydrogeochemical become important highlights in groundwater studies because groundwater conditions in quality and quantity influenced by the geological formation of rock minerals in aquifer. Naturally, the condition of the research area which consists of peat swamps can also affect the characteristics of groundwater. The aims of this research are to determine groundwater types and groundwater facies in study area with an analytical approach using stiff diagram and piper diagram. The method used was purposive sampling by collecting data from dug wells at the research site. 5 samples from dug wells were used as representatives in the groundwater facies analysis. The groundwater facies analysis was carried out by measuring the concentration of major ions such as Na, K, Ca, Mg, Cl, SO4, and HCO3. The highest groundwater level was in the northern part of study area (7,84 m) while the lowest groundwater level was in the southwest part of study area (2,05 m). The results showed three types of groundwater based on stiff diagram as sodium chloride (NaCl), sodium sulfate (NaSO4) and magnesium sulfate (MgSO4). The lithology conditions that composed the aquifer affected the facies or origin of groundwater. The alluvium layer in the research area which rich in sodium (Na+) minerals with chloride (Cl-) or sulfate (SO42-) anions forms chloride sulfate facies (Cl+SO4) which were located in the middle to the south of the study area and sodium (potassium) chloride (sulfate) facies (Na(K)Cl(SO4)) which were distributed in the northern part of study area.

Influence of Multi-Layered Structure of Vadose Zone on Ecological Effect of Groundwater in Arid Area: A Case Study of Shiyang River Basin, Northwest China

The natural vegetation in arid areas of northwest China is strongly dependent on the availability of groundwater. Significantly, capillary water plays an essential role in regulating the ecological groundwater level in the multilayered structure of the vadose zone. The soil-column test and field survey in the lower reaches of the Shiyang River Basin were conducted to investigate the influence of the multi-layered structure of the vadose zone on maintaining the ecological effect of groundwater. Based on the field survey, the results show that the depth of groundwater is 3.0 m, and the rising height of capillary water is 140 cm. In the soil-column test, the height of the wetting front of the column was 125 cm. During the water releasing test, the water held by the vadose zone was 182.54 mm, which would have maintained Haloxylon’s survival in a growing season. Therefore, the multi-layered structure of the vadose zone extends the ecological groundwater depth and consequently enhances the ecological function of groundwater. Importantly, with a lower groundwater level, the clay soil layer within the rising height range of the original capillary water would hold more water and maintain a higher water content for a certain period to supply surface vegetation.

Groundwater Recharge Assessment Using Multi Component Analysis: Case Study at the NW Edge of the Varaždin Alluvial Aquifer, Croatia

Exploring the interaction between precipitation, surface water, and groundwater has been a key subject of many studies dealing with water quality management. The Varaždin aquifer is an example of an area where high nitrate content in groundwater raised public concern, so it is important to understand the aquifer recharge for proper management and preservation of groundwater quality. The NW part of the Varaždin aquifer has been selected for study area, as precipitation, Drava River, accumulation lake, and groundwater interact in this area. In this study, groundwater and surface water levels, water temperature, water isotopes (2H and 18O), and chloride (Cl−) were monitored in precipitation, surface water, and groundwater during the four-year period to estimate groundwater recharge. Head contour maps were constructed based on the groundwater and surface water levels. The results show that aquifer is recharged from both Drava River and accumulation lake for all hydrological conditions–low, mean, and high groundwater levels. The monitoring results of water temperature, chloride content, and stable water isotopes were used as tracers, i.e. as an input to the mixing model for estimation of the contribution ratio from each recharge source. The calculation of mixing proportions showed that surface water is a key mechanism of groundwater recharge in the study area, with a contribution ratio ranging from 55% to 100% depending on the proximity of the observation well to surface water.

Groundwater lowering for construction of the Kilsby Tunnel, UK – pumping and tunnelling

The Kilsby Tunnel, constructed in the 1830s under the direction of Robert Stephenson, faced severe problems when a section of the tunnel, almost 400 m long, was driven through water-bearing unstable ‘quicksand’ conditions. Contemporary methods were not well suited to tunnelling through such conditions, and in previous decades, several canal tunnels had been planned to specifically divert around expected ‘bad ground’, and others took years to complete at great expense. Stephenson’s team, drawing on their experience from the mining industry, did not take this approach and ultimately worked through the unstable ground, albeit with considerable delays and cost increases. This was achieved in part by establishing a large-scale groundwater pumping system, unique for the time, that lowered groundwater levels and stabilised the quicksand, which resulted from a buried channel of glaciofluvial sands, cut into bedrock, that had been missed by trial borings. Steam engines were used to pump from multiple shafts (including four dedicated pumping shafts, off set from the tunnel alignment), with a reported pumping rate of 136 l/s for several months. One unusual feature was the use of flatrod systems to transmit mechanical power horizontally; this allowed a single engine to drive pumps in several different shafts.

Effect of Brick kilns emissions on land, water, agriculture production, socio-economic and livelihood status: A Review

Rapid growth in population leads to urbanization resulting in considerable land use, land covers changes, and creates a sequence of environmental and food security problems. Due to speedy urbanization the agricultural lands has been converted into no-agricultural activity such as brick production. Brick kilns required larger areas for brick production and it removes agriculturally productive topsoil rich in clay, soil organic matter content and others important soil nutrient that is viable for agricultural growth. In addition to the removal of fertile top soil, brick kilns making process also emits harmful gases into the atmosphere. This harmful gaseous emission from brick kilns impacts the available natural resources and livelihood nearby it. Its emission results in decreased land and plant productivity, lowered ground water levels, and particularly leads to air pollution. It was found that neighbouring areas of brick kilns has low organic matter content and soil nutrients, and high soil electrical conductivity and low pH. It also changes the chemical and biological characteristics of soil and water. A change in physical, chemical and biological parameters of soil and water leads to reduce cultivated areas, and finally reduces agricultural production and productivity. It also directly impacts the food production system and could threaten the livelihood of present and future generations by degrading agricultural soil and consequently also eroding the economic basis of farmers.

Vulnerability of water resources under a changing climate and human activity in the lower Great Lakes region

AbstractGlobally, the number of people experiencing water stress is expected to increase by millions by the end of the century. The Great Lakes region, representing 20% of the world's surface freshwater, is not immune to stresses on water supply due to uncertainties on the impacts of climate and land use change. It is imperative for researchers and policy makers to assess the changing state of water resources, even if the region is water rich. This research developed the integrated surface water‐groundwater GSFLOW model and investigated the effects of climate change and anthropogenic activities on water resources in the lower Great Lakes region of Western New York. To capture a range of scenarios, two climate emission pathways and three land development projections were used, specifically RCP 4.5, RCP 8.5, increased urbanization by 50%, decreased urbanization by 50%, and current land cover, respectively. Model outputs of surface water and groundwater discharge into the Great Lakes and groundwater storage for mid‐ and late century were compared to historical to determine the direction and amplitude of changes. Both surface water and groundwater systems show no statistically significant changes under RCP 4.5 but substantial and worrisome losses with RCP 8.5 by mid‐century and end of century. Under RCP 8.5, streamflow decreased by 22% for mid‐century and 42% for late century. Adjusting impervious surfaces revealed complex land use effects, resulting in spatially varying groundwater head fluctuations. For instance, increasing impervious surfaces lowered groundwater levels from 0.5 to 3.8 m under Buffalo, the largest city in the model domain, due to reduced recharge in surrounding suburban areas. Ultimately, results of this study highlight the necessity of integrated modelling in assessing temporal changes to water resources. This research has implications for other water‐rich areas, which may not be immune to effects of climate change and human activities.

Three-Dimensional Surface Deformation Characteristics Based on Time Series InSAR and GPS Technologies in Beijing, China

Excessive exploitation of the groundwater has resulted in obvious three-dimensional (3D) deformation features on the surface of the Beijing Plain. This paper, by combining Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) technologies, has obtained time-series information of the 3D surface deformation in the Beijing Plain, analyzing its spatial distribution characteristics. On this basis, the relationship between different controlling factors with the 3D deformation of the surface has been analyzed as well. The following results are obtained: (1) From 2013 to 2018, the land subsidence, which generally showed the trend of slowing down, was mainly concentrated in the eastern, northern, and southern regions of Beijing Plain, with multiple subsidence centers. (2) Under the International Terrestrial Reference Frame 2005 (ITRF2005), the horizontal direction of all GPS points in the plain is basically the same, with the dominant movement direction being NE112.5°~NE113.8°. Under the Eurasian reference frame, the horizontal movement rate of GPS points significantly decreases. The movement rate and direction of each point are not characteristic of overall trend activity. (3) The distribution and extent of the 3D surface deformation in the Beijing Plain are controlled by the basement structure. Part of the subsided area corresponds to a Quaternary depression formed at the junction of active faults disrupting the area. Similarly, the distribution of horizontal deformation in the E-W and N-S directions of the plain is controlled by the regional basement structure comprising major faults bounding horizontal deformation. (4) Groundwater exploitation is the main cause of the 3D surface deformation in the Beijing Plain. The groundwater funnels of the second and third confined aquifer are in suitable agreement with the land subsidence. The horizontal movement in the Beijing Plain is either directed toward the center of the groundwater or the land subsidence funnel, and the deformation is directed from areas with higher to areas with lower groundwater levels.

Phosphorus Behaviour and Its Basic Indices under Organic Matter Transformation in Variable Moisture Conditions: A Case Study of Fen Organic Soils in the Odra River Valley, Poland

Lowering of groundwater levels caused by anthropogenic changes in the environment gives rise to global problems, most of which relate to soil degradation such as land desertification or organic soil degradation. The transformation of drainage-sensitive organic soils causes many irreversible changes during organic matter (OM) transformation. Phosphorous (P) behaviour is one of the aspects of OM transformation that requires further investigation, due to the P transformations’ complex dependency on many environmental factors. Our study aimed to characterise behaviour of P and find indices reflecting P changes under the influence of OM transformation in drained organic soils in the Odra river valley. The studies were carried out on soils representing different stages of soil degradation in which basic soil properties, including different P forms, were determined with commonly used methods. The results showed significantly higher content of soluble P forms (Pw, PCaCl2, PM3), particularly in the most drained postmurshic soil (P1). The indices used in this study—Ip, PSD, C:Pt, N:Pt—reflected well the P and OM transformations in organic soils degraded by drainage. This was indicated by numerous statistically significant relationships between the indices and basic soil properties (e.g., Ash, C, N), as well as different P forms (Pt, Pmin, Pox, Porg, Pw, PCaCl2, PM3). The PSD and Ip values increased and the C:Pt and N:Pt ratios decreased with the degree of OM mineralisation and the degree of site drainage (P3 &lt; P2 &lt; P1).

Assessing Water Poverty of Livelihood Groups in Peri-Urban Areas around Dhaka under a Changing Environment

Water poverty, measured by the Water Poverty Index (WPI), is traditionally applied at country and community levels. This study presents a livelihood-inclusive approach for measuring WPI at the livelihood group level. The specific objectives are to evaluate present and future WPIs for different livelihood groups, such as large and small male farmers, female farmers, male and female industrial workers and economically inactive women. Primary data are collected from three peri-urban areas around Dhaka using a mixed approach, including a semi-structured questionnaire survey of 260 respondents. The WPIs are calculated by using a weighted multiplicative function, and the component weights are assigned by principal component analysis. The results show that the economically inactive women are presently the most water-poor group, with a WPI value of 41, whereas the small male farmers would be the most water-poor group in the future, with a WPI value of 34. Environmental changes, such as high temperature, variability in rainfall and surface water, lowering of groundwater level, rapid population growth and unplanned urbanization, are found to be responsible for the dynamism in WPIs for different livelihood groups. The Resource and Environment components should be paid immediate attention in order to protect peri-urban livelihood groups from future water poverty.

Current understanding of groundwater recharge and groundwater drought in Sweden compared to countries with similar geology and climate

ABSTRACT Recently, groundwater in Sweden has attracted media attention due to supply shortages caused by dry periods and low groundwater levels. About half of Swedish drinking water stems from groundwater. The small Swedish aquifers are highly dependent on frequent and sufficient recharge. Groundwater recharge forms the link between meteorological and groundwater drought and thus the main link between climate change and sustainable water supply. This study evaluated whether the current knowledge on groundwater recharge and groundwater drought is sufficient to mitigate the impacts of climate change. A review of international literature on groundwater recharge in regions with conditions similar to Sweden was performed. National literature was compared and links to international studies evaluated. A survey among Swedish groundwater experts complemented the study. Findings are that research on groundwater recharge has been scarce in Sweden over the last decades and Swedish experts seem to not have taken much notice of international literature. It is concluded that Sweden is not well prepared to predict the impact of climate change on groundwater resources, as the most crucial process linking climate to groundwater is not well understood. The study has a strong focus on Sweden, however, the results are also relevant for countries with similar geology and climate. One main conclusion is that groundwater recharge studies often remain unique, and thus hardly transferable and comparable. Two or more independent studies are rarely applied in parallel, verification based on direct groundwater observations is not common. This raises concerns about the reliability of climate change impact predictions on groundwater.

Drainage canal impacts on smoke aerosol emissions for Indonesian peatland and non-peatland fires

Indonesia has experienced frequent fires due to the lowering of groundwater levels caused by drainage via extensive canal networks for agricultural development since the 1970s. However, the impact of canals on fire emissions is still poorly understood. Here we investigate canal impacts on smoke aerosol emissions for Indonesian peatland and non-peatland fires by quantifying the resulting changes of smoke aerosol emission coefficient (Ce) that represents total aerosol emissions released from per unit of fire radiative energy. First, we quantified the impacts of canal drainage and backfilling on water table depth (WTD) variations using field data and then expanded such impacts from field to regional scales by correlating field WTD to satellite terrestrial water storage (TWS) anomalies from Gravity Recovery and Climate Experiment. Second, we estimated Ce from fire radiative power and smoke-aerosol emission rates based on Moderate Resolution Imaging Spectroradiometer active fire and multi-angle implementation of atmospheric correction aerosol products. Finally, we evaluated the Ce variation with TWS anomalies. The results indicate: (a) Ce is larger in peatland fires than in non-peatland fires; (b) Ce increases significantly as TWS anomalies decrease for both peatland and non-peatland fires; and (c) Ce changes at nearly twice the rate in peatland for a given TWS anomaly range as in non-peatland. These phenomena likely result from the different fuel types and combustion phases prevalent under different moisture conditions. These findings support the Indonesian government’s recent peatland restoration policies and pave the way for improved estimation of tropical biomass burning emissions.