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"Subsurface water"
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Groundwater lowering in construction : a practical guide to dewatering
Many engineering construction projects entail excavations into water bearing substrates. The authors explain the drainage techniques required to lower groundwater sufficiently to allow projects to be undertaken with confidence.
Book
Rapid Intensification of Hurricane Ian in Relation to Anomalously Warm Subsurface Water on the Wide Continental Shelf
Hurricane Ian rapidly intensified from Category 3 to 5 as it transited the wide West Florida Shelf (WFS). This is ascribed to heating by the anomalously warm shelf waters, despite the water depth being shallow when compared to the thicker, mixed layer areas of the deeper ocean. By examining temperature from long‐term moorings, we found that the sea surface and subsurface temperatures exceeded the climatologies by 1–2°C and 2–3°C, respectively. Additionally, these anomalously high temperatures in summer/fall of 2022 were related to the absence of Gulf of Mexico Loop Current interactions with the WFS slope at its “pressure point”. Without such offshore forcing to induce an upwelling circulation, the warmer waters on the shelf were not flushed and replaced by colder waters of deeper ocean origin. This work highlights the importance of subsurface temperature and ocean circulation monitoring on shallow continental shelves, which are largely overlooked in hurricane‐related ocean heat content observational programs. Plain Language Summary Rapid intensification of tropical cyclones can be fueled by upper ocean warm water. The favorable environment of high ocean heat potential is thought to be more likely during marine heatwaves. However, both the hurricane heat potential and marine heatwaves are primarily calculated from satellite‐derived sea surface data, with subsurface data largely overlooked due to lack of in situ measurements, particularly in coastal oceans where hurricanes may rapidly intensify before making landfall. Here we examine an unprecedented set of coastal ocean temperature records from long‐term (26 years) moorings on the wide West Florida Shelf for the cause of Hurricane Ian's rapid intensification to a Category 5 hurricane in 2022. We found that while sea surface temperatures exceeded their climatological mean values by 1–2°C in summer/fall of 2022, the subsurface temperature exceedances were even higher (2–3°C). These anomalously warm waters were further ascribed to a lack of a coastal ocean upwelling circulation due to the absence of offshore forcing by the Gulf of Mexico Loop Current. This work highlights the importance of subsurface temperature and current monitoring on shallow continental shelves, which are largely overlooked in hurricane‐related ocean heat content observing programs. Key Points Hurricane Ian (2022) rapidly intensified over a wide continental shelf with subsurface water 2–3°C warmer than climatology The anomalously warm water was related to the absence of Gulf of Mexico Loop Current interactions with the shelf slope Coastal ocean circulation and subsurface temperature monitoring is important for future hurricane intensification forecasts
Journal Article
Assessment of water quality and health hazards using water quality index and human health risk evaluation in district Talagang Pakistan
This work was carried out for the determination of the water quality in the Talagang District of Pakistan, as water is essential for agriculture and drinking uses. This study aims to assess the water quality for irrigation, drinking, and health risks using the Water Quality Index (WQI) and Human Health Risk Assessment (HHRA) tools to identify regions with contaminated water, and to evaluate the associated risks. A total of 98 water samples were taken at various points from diverse sources such as hand pumps, streams, springs, dug wells, and tube wells for physio-chemical assessment. In the current study, the effectiveness of the irrigation water quality index (IWQI), human health risk assessment (HHRA), and water quality index (WQI) tools have been assessed. The characteristics of subterranean water are influenced by evaporation, ion exchange, rock-water interaction, and parent-rock weathering, as shown by the Piper and Gibbs diagram. According to the WQI results, the water quality is 20. 89% and 27.46% of the sample sites are moderate and poor, making them unfit for human intake. Based on HHRA, compared to adult males and females in the study area, children are deemed to be at a higher risk. A larger number of the sample localities are appropriate for irrigation purposes. The study assists in identifying contaminated regions and in monitoring newly implemented remediation actions to manage the source of contaminants in the study area.
Journal Article
Radiokrypton unveils dual moisture sources of a deep desert aquifer
In arid regions, groundwater is a vital resource that can also provide a long-term record of the regional water cycle. However, the use of groundwater as a paleoclimate proxy has been limited by the complex hydrology and the lack of appropriate chronometers to determine the recharge time without complication. Applying 81Kr, a long-lived radioisotope tracer, we investigate the paleohydroclimate and subsurface water storage properties of the Nubian Sandstone Aquifer in the Negev Desert, Israel. Based on the spatial distributions of stable isotopes and the abundance of 81Kr, we resolve subsurface mixing and identify two distinct moisture sources of the recharge: one recent (<38 ky ago) from the Mediterranean and the other 361 ± 30 ky ago from the tropical Atlantic, both of which occurred under conditions of low orbital eccentricity comparable to that of the present. The recent recharge provided by the moisture from Mediterranean cyclones can be attributed to the southward shift of the storm track during the Last Glacial Maximum, and the earlier recharge can be attributed to moisture from the Atlantic delivered as tropical plumes under a climate colder than the present. Furthermore, the residence time of the latter reveals that tectonically active terrain can store groundwater for an unexpectedly long period, likely due to strongly attenuated groundwater flow across the fault zones. With this tracer, groundwater can now serve as a direct record of paleoprecipitation over land and of subsurface water storage from the mid-Pleistocene and onward.
Journal Article
Comparative Performance of Multivariable Agro-Physiological Parameters for Detecting Salt Tolerance of Wheat Cultivars under Simulated Saline Field Growing Conditions
Field-based trials are crucial for successfully achieving the goals of plant breeding programs aiming to screen and improve the salt tolerance of crop genotypes. In this study, simulated saline field growing conditions were designed using the subsurface water retention technique (SWRT) and three saline irrigation levels (control, 60, and 120 mM NaCl) to accurately appraise the suitability of a set of agro-physiological parameters including shoot biomass, grain yield, leaf water relations, gas exchange, chlorophyll fluorescence, and ion accumulation as screening criteria to establish the salt tolerance of the salt-tolerant (Sakha 93) and salt-sensitive (Sakha 61) wheat cultivars. Shoot dry weight and grain yield per hectare were substantially reduced by salinity, but the reduction was more pronounced in Sakha 61 than in Sakha 93. Increasing salinity stress caused a significant decrease in the net photosynthesis rate and stomatal conductance of both cultivars, although their leaf turgor pressure increased. The accumulation of toxic ions (Na
and Cl
) was higher in Sakha 61, but the accumulation of essential cations (K
and Ca
) was higher in Sakha 93, which could be the reason for the observed maintenance of the higher leaf turgor of both cultivars in the salt treatments. The maximum quantum PSII photochemical efficiency (
/
) and the PSII quantum yield (ΦPSII) decreased with increasing salinity levels in Sakha 61, but they only started to decline at the moderate salinity condition in Sakha 93. The principle component analysis successfully identified the interrelationships between all parameters. The parameters of leaf water relations and toxic ion concentrations were significantly related to each other and could identify Sakha 61 at mild and moderate salinity levels, and, to a lesser extent, Sakha 93 at the moderate salinity level. Both cultivars under the control treatment and Sakha 93 at the mild salinity level were identified by most of the other parameters. The variability in the angle between the vectors of parameters explained which parameters could be used as individual, interchangeable, or supplementary screening criteria for evaluating wheat salt tolerance under simulated field conditions.
Journal Article
Impact of Using Subsurface Water Retention Technology on Improving Water Use Efficiency of Furrow Irrigation System
Evaluation was carried out on the existing furrow irrigation system located in an open agricultural field within Hor Rajabh Township, south of Baghdad, Iraq (latitude: 33°09’ N, longitude: 44°24’ E). Two plots were chosen for comparison: treatment plot T1, which used subsurface water retention technology (SWRT) with a furrow irrigation system. While the treatment plot T2 was done by using a furrow irrigation procedure without SWRT. A comparison between the two treatment plots was carried out to study the efficiency of the applied water on crop yield. In terms of agricultural productivity and water use efficiency, plot T1 outperformed plot T2, according to the study’s final findings. Compared with plot T2, the rate of increase in the efficiency of water and crop yield were found to be 44.9% and 14.2%, respectively. Additionally, compared to plot T1, the rate of increase in the applied water in plot T2 was 26.8%. The efficiency of plot T1 is attributed to the usage of SWRT membranes beneath the plant’s root zone, which helped conserve water and nutrients, which affected crop yield and water consumption.
Journal Article
Regulation of Water Masses to Hypoxia Zones in the Changjiang Estuary
The regulating ways of different water masses affecting the locations and intensities of hypoxia zones were studied based on the time-space continuum data from August 2011 to 2013–2017. The 6-year distribution of the hypoxic area in the Changjiang Estuary (CE) and its adjacent waters show that the hypoxic area can be divided into two segments. The southern segment is out of the south branch of the CE, whereas the northern segment is in the junction zone between the South Yellow Sea and the CE. The two segments were divided along the 31.5°–32 °N latitude line. The northern and southern segments were dominated by the East China Sea shelf water (ECSSW) and Kuroshio subsurface water (KSW), respectively. When the KSW (salinity > 34) intrusion reached the east of 123 °E and south of 31 °N, hypoxia zones mainly occurred in the southern segment covered by the Changjiang Diluted Water (CDW), meanwhile the Yellow Sea cold water mass may emerge in the northeastern area. When the KSW intensely invaded westward to the region between 122° and 122.5°E and northward to 31.5°N or further north, hypoxia zones appeared in the northern segment. The strength of the KSW with low dissolved oxygen concentration is the basic driving factor for the hypoxia occurrence in the CE. Moreover, the stratification is crucial for the southern segment, whereas the organic matter decomposition is dominated for the northern segment, even with severe hypoxia across the sea surface in the study area.
Journal Article
How Subsurface Water Technologies (SWT) can Provide Robust, Effective, and Cost-Efficient Solutions for Freshwater Management in Coastal Zones
Freshwater resources in coastal zones are limited while demands are high, resulting in problems like seasonal water shortage, overexploitation of freshwater aquifers, and seawater intrusion. Three subsurface water technologies (SWT) that can provide robust, effective, and cost-efficient solutions to manage freshwater resources in the subsurface are evaluated using groundwater modelling and validation at field-scale: (1) ASR-coastal to store freshwater surpluses in confined brackish-saline aquifers for recovery in times of demand, (2) the Freshkeeper to counteract salinization of well fields by interception and desalination of upconing brackish groundwater, and (3) the Freshmaker to combine ASR and Freshkeeper to enlarge the volume of natural freshwater lenses for later abstraction. The evaluation indicates that SWT can be used in various hydrogeological settings for various hydrogeological problems like seawater intrusion, upconing, and bubble drift during ASR and have significant economic benefits. Although only sporadically applied to date, we foresee that SWT will stimulate (cost-)efficient and sustainable exploitation of various freshwater sources (like groundwater, rainwater, treated waste water, surface water) in coastal zones. Prolonged SWT testing in the current pilots, replication of SWT in other areas worldwide, and the development of technical and non-technical support tools are required to facilitate potential end-users in investment decision making and SWT implementation.
Journal Article
Detection of subsurface water pipeline under SZJT Track Using Ground-Penetrating Radar Method
Surabaya’s public facilities and rapid infrastructure development will change the physical environment and require careful attention in all aspects of development. One aspect is the location determination of subsurface objects such as gas pipes, electrical cable lines, and water pipes. Lack of pipeline management and mapping can fail underground pipeline identification during excavation. The subsurface water pipe is one of the most important things to support people’s needs. Knowing the location of these pipes is essential for government agencies in carrying out maintenance, pipeline development, and repair activities. We identified the subsurface water pipeline using the Ground-Penetrating Radar (GPR) method. It is because of a non-destructive working type and very well applied in investigating underground infrastructure with significant electromagnetic contrast with the surrounding soil. We conducted this research around Surabaya Zoo and Joyoboyo Terminal (SZJT) track. We conducted data acquisition with the GPR GSSI SIR-3000 system with a shielded antenna frequency of 270 MHz on 21 measurement lines (JB07 to JB27). The aim is to determine the location, depth, and structure of the subsurface water pipeline at the research location. We processed the measurement data using MatGPR R-3.1 software by adjusting signal position, dc removal, dewow, median filter, inverse amplitude decay, background removal, K-L filter, bandpass filter, and time-to-depth conversion. We conducted 2-D and 2.5-D modeling to visualize the water pipeline. A hyperbolic anomaly, suspected to be a water pipe, is detected from the presence of high amplitude at a depth of 1 – 2 meters, which we saw in almost every line with velocity values from 0.0609 - 0.113 m/ns and dielectric constant value of 7.05 – 24.27. The 2.5-D modeling shows that the water pipeline continues from the research location’s south (Surabaya River) to the north.
Journal Article
A Priori Constrained ACO Method Applied to Three-Dimensional Imaging of Subsurface Electrical Resistivity
Electrical resistivity imaging seeks to reconstruct conductivity model of subsurface water-bearing body for disaster reduction and resource protection. Since its high non-linearity, the inverse problem relying mainly on linear least-square method may inclined to consider much deeper adoption of non-linear algorithm. Ant colony optimization (ACO) is a standard probabilistic algorithm used to find optimal paths. Since the direct application of the ACO is unstable, there are many false anomalies, and prior information needs to be applied according to the laws of physical properties. This study proposed a priori constrained approach to improving ant colony optimization method wherein prior information is included as regularization term in search process. First, we introduce foraging path smoothness into objective function to reduce non-uniqueness. On this basis, smooth constraint of resistivity is added into visibility and inequality constraint is added into pheromone intensity, by which some unnecessary nodes of foraging paths are avoided form selecting by ants. Finally, the strategy of global minimum is introduced in the process of updating pheromone. Forward modeling of each ant selected is parallel calculated via shared-memory computing strategy. Taking into account of those, the direction of global minimum is maintained and the search efficiency is improved greatly, which makes the constrained ACO feasible for the 3-D resistivity inversion. Both numerical experiments and field application is conducted to evaluate this method and illustrate that we can obtain the improved inversion results of subsurface water-bearing body.
Journal Article