Water Ingress Research Articles

INVESTIGATION INTO THE PERFORMANCE OF RIGID PAVEMENT JOINTS AND SEALANTS

This study, conducted by the Georgia Department of Transportation, examines the effectiveness of various joint sealants in rigid pavements over a five-year period. Focusing on a test area along I-20 east of Atlanta, the research involved the construction of 32 test sections with different joint spacings and angles, utilizing eight types of sealants including polysulfide and polyurethane polymers, rubberized asphalt, neoprene, and polyvinylchloride (PVC). The study meticulously monitored the installation process to ensure optimal sealant performance. Key findings suggest significant differences in performance among the sealants, with specific recommendations against using polysulfide and polyurethane for contraction joints unless shape factors are modified. Moreover, the study emphasizes the importance of watertight seals to prevent pavement deterioration due to water ingress and subsequent base material loss, which can lead to slab cracking and reduced ride quality. Recommendations also include the potential use of low modulus silicone for sealing shoulder joints due to its durable and flexible properties, particularly in colder conditions. The study highlights the critical role of proper joint sealing in extending the lifespan and functionality of concrete roadways, providing essential insights for pavement maintenance and construction standards. (Abstract generated by AI tool ChatGPT 4)

A Comparative Study of Supervised Machine Learning Techniques for Water Leakage Prediction in Drill and Blast Excavated Water Tunnels in the Himalayan Region

In the Himalayan region, drill and blast (DB) method excavated water tunnels often pass through complex geological rock mass conditions which were formed with frequent tectonic movements. Due to these tectonic movements, the rock mass conditions in the Himalayas are highly faulted, folded, jointed, sheared, and fractured. The geological formations are the pathway for the water ingress and leakage out in the water tunnel. This water leakage in the tunnel causes a complicated geological hazard, which significantly increases tunnel instability and can lead to a delay in completion time and finally increase the cost of the tunnel project. Therefore, an efficient water ingress/leakage prediction model is essential to mitigate these challenges. In this research, various field data such as rock mass properties, topography, and permeability data sets were collected from the Nilgiri-II Hydroelectric project water tunnel. These real-time field datasets have been used for comprehensive assessment and to predict the water ingress/leakage in the water tunnel by using four supervised machine learning (ML) approaches such as Support Vector Regression (SVR), Decision Tree (DT) regression, K-Nearest Neighbors (KNN) and Random Forest (RF) regression models. It was observed that the KNN shows the best regression performance of 93% followed by RF of 92%, DT of 86%, and SVR of 66%. Therefore, all these machine learning approaches show good performance in predicting water ingress/leakage based on real field data except the SVR model.

Impact of oil-water emulsions on lubrication performance of ship stern bearings

During maritime operations, extreme events such as explosions, grounding, and seal failures can cause water ingress into lubricant compartments, forming oil-water emulsions that significantly affect the lubrication performance of ship stern bearings. Existing studies mainly focus on low water content, with limited exploration of the impact of high water content on lubrication performance. To address this gap, viscosity measurements of oil-water mixtures were conducted, and an emulsification viscosity equation applicable to varying water contents was derived. A thermal elastohydrodynamic lubrication model for stern bearings, incorporating rough surface contact and emulsification viscosity, was developed. Numerical results reveal two flow regimes of oil-water mixtures—water-in-oil (W/O) and oil-in-water (O/W)—each exhibiting distinct lubrication behaviors. In the high-viscosity W/O regime, water contamination increases lubricant viscosity, raises minimum oil film thickness, and lifts the journal, but significantly increases the friction coefficient and power consumption. The high specific heat capacity of water mitigates the temperature rise caused by increased viscosity. In the low-viscosity O/W regime, the mixture shows lower temperature rise and friction power under high-speed light-load conditions. However, under low-speed heavy-load conditions, the lubrication transitions to the boundary regime, leading to sharp increases in friction and temperature detrimental to bearing performance. This study highlights the critical influence of water content in oil-water emulsions on stern bearing lubrication, providing valuable insights for improving bearing design and operational reliability.

Chemical Modification of Carbon Black for Coloring

Sealing profiles that are mainly used to prevent the ingress of water, noise, dust and air in the automotive industry are produced from synthetic Ethylene-propylene-diene monomer (EPDM) rubber. Although EPDM rubber is preferred due to its high mechanical properties and waterproof structure, it is necessary to reinforce it with various additives due to the requirements for profiles in automotive manufacturers' specifications. One of the fillers used to keep the fluidity at the desired level during production and to improve the mechanical properties and UV resistance of the profiles is carbon black (CB) and has the highest contribution rate in the EPDM rubber formulation. Due to its high amount in the rubber formulation, it allows the rubber formulation and subsequently the sealing profiles produced with this formulation to be produced only in black. However, recently, automotive manufacturers have demanded different color profiles in line with the demands of end users. Solubility and reactivity of CB is low and it tends to aggregate. In order for CB to be colored, its surface will be activated and polarized using different chemicals. After that, a suitable dye can be attached to the structure after its structure has been determined by elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX) and Thermal Analysis (TGA-DSC). After EPDM rubber will be produced by colored CB, the first colored sealing profile that has not been produced in our country and in the world yet, can be achieved.

The shard test and nanoporomechanics reverse classical paradigm of cement hydration being contractive

Le Chatelier in 1887 and Powers in 1947 demonstrated that the volume of nanoscale C-S-H (calcium silicate hydrate) particles formed during hydration is smaller than the combined volume of the reactants-the anhydrous Portland cement and water. Hydration has thus been considered as contractive. An experiment shows that the opposite is true above the nanoscale. The porous skeleton of cement paste expands as the growing C-S-H particles push each other apart, similar to crystal growth pressure. This is significant for high-performance concretes (HPC) with low water-cement ratios (w/c [Formula: see text] 0.4), where chemical self-desiccation lowers pore relative humidity by 40%, compared to just 1% in traditional concretes (w/c [Formula: see text] 0.5). Standard American Society for Testing and Materials (ASTM) C1608 tests, using 10 mm thick water-immersed specimens, show large shrinkage because the half-time of water ingress is many decades, unable to offset shrinkage-causing self-desiccation. The present experiment, using a laser microscopy-topography technique, proves the opposite-expansion, evidenced by measuring the length changes of water-immersed HPC shards 0.5 mm thick in which the diffusion halftime, only about one hour, allows continuous resaturation of pores, canceling self-desiccation. The faster diffusion (halftime of one hour) enables continuous pore resaturation, preventing shrinkage. When sealed with paraffin oil, the shards self-desiccate and shrink. These findings align with studies since 2015, showing that models excluding hydration expansion cannot fit test data across various specimen sizes and sealing conditions. The results suggest that standardized ASTM tests for the so-called chemical shrinkage in modern concretes with very low water-cement ratios are misleading and need revision.

Rehabilitation of Concrete Structures - A Review

Concrete is considered as a material that is heavily relied on in the construction of infrastructures, buildings, bridges, highways, etc. Concrete structures need to be checked and maintained periodically in order to avoid the progression of any cracks to the concrete elements. However, there are some circumstances and problems that causes the deterioration of the concrete structure either totally or partially. In such cases, the repairing techniques, methods and materials cannot serve as a good solution to stop and solve the deterioration. Thus, rehabilitation and retrofit techniques arise to be the only choice that can solve the deterioration of concrete structures. The progression and initiation of damages into the concrete sections may cause a reduction in the durability and strength of the system. Rehabilitation techniques are used to stop the damages and enhance the performance of deteriorated concrete structures where they can restore their strength and durability. These damages may occur due to the ingression of alkaline water, sulfate attack, chloride attack, corrosion of steel bars, freeze and thaw cycles, environmental changes, fire attack, thermal changes, etc. Several measures shall be taken into account while choosing the rehabilitation technique. The environment surrounding, the section type, the properties of the section that must be enhanced, the location of the concrete members that need rehabilitation, all these factors shall be taken into consideration before choosing any rehabilitation technique since each one can be used in specific places. Different equations are used in order to calculate the properties and capacities of members’ after being rehabilitated.

Capillary rise in a packing of glass spheres

A series of experiments are performed to give insight into the mechanisms of liquid rise in a 3D dense random packing of glass spheres. A sharp knee in the log-log plot of water height h versus time t curve is observed, with an attendant change in h(t) characteristic from h∝t0.5 to h∝t0.05. This behaviour is observed for 5 choices of diameter distribution of spheres, such that the mean diameter is in the range of 0.22 mm to 1.20 mm, and the ratio of standard deviation to mean diameter lies between 0.014 and 0.157. Immediate arrest in water rise occurs when the water reservoir is removed from the bottom of the column, in support of the conclusion that water rise is by capillary action. In the post-knee regime of the h(t) response, water rise occurs in a jerky manner by a series of jumps, involving transverse jumps and more occasional vertical jumps in water ingress; each jump is by an increment of sphere diameter. The incubation time for each vertical jump is sensitive to height of meniscus and dictates the overall rate of water rise. Pendular-rings at the junctions between glass spheres are not observed above the meniscus; this casts doubt upon the notion that the jerky motion of the meniscus is due to the incubation time for a vapour-fed pendular-ring to grow and coalesce with the meniscus. Possible sources of the height-dependent incubation time for each vertical jump are discussed, including a time-dependent increase in surface tension. Additional insight is obtained by observing water rise, and glycerol rise in (i) a monolayer of glass spheres, (ii) in a capillary tube of diameter slightly greater than that of the glass beads and filled with a single column of glass spheres and (iii) an empty capillary tube. Continued liquid rise beyond the knee in the h(t) curve is noted in all cases except for that of an empty capillary tube.

Case study of adjacent integral bridges supported on continuous secant piled walls

Integral bridges are often the preferred way of construction for short and medium span bridges in the UK. However, the behaviour of integral bridges is influenced by complex soil-structure interaction behaviour that may be cumbersome to predict and analyse when dealing with unusual structural arrangements. This paper presents a case study for the design of two single span bridges carrying a roundabout over a dual carriageway, supported on continuous secant piled walls. One of the bridges is fully integral while the adjacent structure is articulated at one end due to its skew. An alternative detail for the articulated end is proposed, to eliminate soil pressures and settlements at the back of the abutments as well as reduce the risk of water ingress to the bearings. The complex nature of the structural arrangement presented analytical challenges, that were solved by developing an advanced modelling approach, exploring two proposals. The first is to evaluate the geotechnical model for a range of imposed top of abutment displacements from the onset. The second, using unique non-linear springs and derived P-Y curves describes the more realistic variable nature of soil-structure interaction over the length of the walls leading to reduced soil pressures enhancing design feasibility.

Hydrolysis of poly(ester urethane): In-depth mechanistic pathways through FTIR 2D-COS spectroscopy

The hydrolysis of thermoplastic poly(ester urethane) (PEU) is convoluted by its block copolymer phase structure and competing hydrolytic sensitivities of multiple functional groups. The exact pathways for water ingress, water interaction with the material and ultimately the kinetics and order of functional group hydrolysis remain to be refined. Additional diagnostics are needed to enable deeper insight and deconvolution of material changes. In combination with GPC results, a promising analytical technique – two-dimensional correlation spectroscopy (2D-COS) – has been reviewed and applied to analyze FTIR spectra of hydrolyzed PEUs aged under various conditions, such as exposure time, temperature, and relative humidity. 2D-COS allows the complex role of water with distinct intermediate steps to be established, plus it emphasizes the initial stages of PEU hydrolysis at more susceptible functional groups. As a complication for the raw material, ATR IR detected some talc on the surface of commercial PEU beads and pressed sheets thereof, which can interfere with water ingress and thereby retards PEU hydrolysis, particularly in its natural form or moderate aging at lower temperatures (e.g., below the melting point of PEU). As aging temperature increases above the melting temperature, even traces of water trapped inside the PEU are sufficient to initiate the hydrolysis, which then progresses strongly with increasing temperatures. Feedback from 2D-COS analysis confirms that PEU hydrolysis starts at esters in the soft-segments before those in the urethane linkage become susceptible. Only when the molecular weight of PEU is below a critical molar mass (Mc) will the hydrolysis occur in parallel in the hard-segments since protective morphological phase structures are then absent. The current observations demonstrate unexpected behavior that may result from 'unknown' additives in polymer degradation, the temporal and group-specific hydrolysis of PEU as a function of locally available water molecules, the order of reactivity of susceptible functional groups, and the importance of changes in molecular weight coupled with the phase structure of the polymer.

Prevention of water ingress during the operation of oil wells at some facilities of the Siyazan monoclinal field

The Siyazan monocline is located in the Caspian-Guba oil-gas region and stretches for 90 km along the foothills of the South-Eastern Caucasus. This 800 m wide strip-shaped area is located between Zorat station and Karachay. It consists of areas with different structures according to the terrain. It stretches from Atacay to Kilkilay in the southeast with a coastal plain and low hills, while the North-West area passes through relatively high plains and forests. Wells are often drilled deep (about 1000 m long and more), equipped with uncemented, ready-made filter casing, and the entire unit is operated together. The upper part of the unit consists of oil-saturated chalk sediments, and the lower part consists of non-retentive (clay-sandy) rocks. As a result, only the upper part of the bed is exploited. The surface of the Siyazan monoclinal deposit has many water networks crossing it (Garachay, Caghajugchay, Valvalechay, Shabranchay, Kilkilachay, Atachay). The tributaries of these water bodies do not dry up even in the summer months. Ready-made filters are used in wells exploiting layers of chalk sediments located at an angle of 70–80o. Over time, irrigation in such wells occurs due to the opening of holes in the perforation interval to large distances and bottom water entering the well from lower wells.

Effect of Natural Weathering on the Mechanical Strength of Bamboo Bio-Concrete

The search for solutions that reduce the environmental impact of construction has driven the development of new materials. Bio-concrete represents a significant advance, presenting itself as an alternative to traditional concrete. Recent studies point to durability in outdoor conditions as one of the main challenges in its application. This paper presents natural durability studies performed on bamboo bio-concrete, produced with a bamboo particle volume of 50%. A surface treatment of applying resin externally was tested to reduce water ingress during weathering. The bio-concretes were exposed to natural and outdoor weather conditions for twelve months, and meteorological records were collected during the study period. The effect and influence of the external resin was investigated using visual surface analysis, uniaxial compression, modulus of elasticity and scanning electron microscopy. In terms of visual aspects, the resin was not effective in preventing loss of gloss, while in terms of microstructure, these samples showed better adhesion between the bamboo particles in the matrix. The compressive strength showed significant reductions of 60% (stress) and 73% (Young’s modulus) after twelve months of weathering. External resin could improve microstructures from surfaces to internal portions and more effectively preserve the mechanical strength of bio-concrete.

Monolayer Amphiphiles Hydrophobicize MoS2-Mediated Real-Time Water Removal for Efficient Waterproof Hydrogen Detection.

Ensuring water-fouling-free operation of semiconductor-based gas sensors is essential to maintaining their accuracy, reliability, and stability across diverse applications. Despite the use of hydrophobic strategies to prevent external water intrusion, addressing in situ-produced water transport during H2 detection remains a challenge. Herein, we construct a novel waterproof H2 sensor by integrating single-atom Ru(III) self-assembly with monolayer amphiphiles embedded in MoS2. The unique monolayer structure enables the sensor to detect H2 in the presence of water, as well as facilitate the self-transport of in situ-generated water from the H2-O2 reaction during H2 detection. Molecular dynamics simulations reveal that monolayer amphiphiles exhibit a higher water diffusion coefficient than multilayer amphiphiles, making them more advantageous for removing in situ-produced water. Deployable on mobile platforms, it enables wireless H2cat detection for up to 6 months, without the introduction of protective membranes against dust and water ingress. This work not only enhances the performance of H2 detection but also introduces a new concept for the advancement of stable water-sensitive sensors.

Influence of Water Ingress at the Shield Tunnel Portal on Tunnel Deformation and Load Capacity Weakening

Abstract. During the construction of shield tunnels, adverse geological conditions can lead to tunnel segment settlement and damage. This study investigates the deformation patterns and changes in load capacity of shield tunnels under water ingress conditions at the portal, using a segment of the Jinan Metro as a case study. Through field measurements and numerical simulations, we analyzed the structural deformation and weakening of load capacity caused by water ingress. The results indicate that significant settlement occurs at both the tunnel crown and invert after water ingress, with a maximum settlement of 181.2 mm compared to the original design axis. The deformation profile of the tunnel primarily resembles a transverse "duck egg" shape, while the segments near the portal exhibit vertical "duck egg" deformations due to grouting and other factors. Multiple cracks and damages were observed in the segments, with up to 16 cracks found in a single ring. Compared to the original design conditions, the bending moment in the tunnel lining increased by approximately 7%, and the axial force increased by about 9%, leading to an 11% reduction in tunnel resistance effects. The findings of this study regarding tunnel lining deformation and load capacity weakening provide valuable insights for similar engineering projects.

Unveiling the impact of absorbent polymers on self-healing efficiency of sludge-derived capsules in cementitious composites

A novel green capsule for self-healing cementitious material using a combination of waste-based materials with an inorganic substance was developed. A mix of alum sludge (AS), a typical waste from the water industry, and calcium hydroxide were used as the primary healing agents. Also, two types of natural and synthetic absorbent polymers (AP), microcrystalline cellulose (MCC) and sodium polyacrylate (SPA), were added to the core mixture to assess their impact on the healing efficiency. The morphology of the produced capsules, the self-healing proficiency of cracked mortars, and the resulting healing materials were characterised. Outcomes revealed that cracks up to 400 µm could be healed by the plain capsule. The closure width was dramatically increased to 500 µm and 800 µm with the inclusion of MCC and SPA, respectively, mainly in 3 days. The expansion, water retention, and bridging properties of the APs enhanced the sealing performance of the capsules by providing nucleation sites and increasing the reaction rates of core materials to generate further calcium-based products inside the cracks. Therefore, higher recovery rates of mechanical strengths, along with a significant reduction in water ingress were achieved. The main healing products were identified as calcite crystals, C-S-H, calcium silicate, and aluminium-bearing phases.

In Situ IR Spectroscopy Studies of Atomic Layer-Deposited SnO2 on Fullerenes for Perovskite Photovoltaics.

In recent years, atomic layer deposition (ALD) has established itself as the state-of-the-art technique for the deposition of SnO2 buffer layers grown between the fullerene electron transport layer (ETL) and the ITO top electrode in metal halide perovskite-based photovoltaics. The SnO2 layer shields the underlying layers, i.e., the fullerene-derivative materials such as C60 and PCBM, as well as the perovskite absorber, from water ingress and damage induced by the sputtering of the transparent front contact. Our study undertakes a comprehensive investigation of the impact of SnO2 ALD processing on fullerenes by means of in situ spectroscopic ellipsometry (SE) and transmission infrared spectroscopy (FTIR). While no difference in SnO2 bulk properties is observed and the perovskite absorber degradation is nearly entirely avoided during exposure to heat and vacuum, when the absorber is introduced beneath the organic ETLs, a SnO2 growth delay of about 50 ALD cycles is measured on PCBM, whereas the delay is limited to 10 cycles in the case of growth on C60. Notably, FTIR measurements show that while C60 remains chemically unaffected during SnO2 ALD growth, PCBM undergoes chemical modification, specifically of its ester groups. The onset of these modifications corresponds with the detection of the onset, after the initial delay, of ALD SnO2 growth. It is expected that the modification that the PCBM layer undergoes upon ALD SnO2 processing is responsible for the systematic lower photovoltaic device performance in the case of PCBM-based devices, with respect to C60-based devices.

The water ingress analysis on steam generator heat-exchange tube rupture accident of high temperature gas-cooled reactor

Steam generator (SG) heat-exchange tube rupture (SGTR) is a unique and severe accident, which will result in water ingress into the reactor. The analysis on water ingress transient of SGTR holds significant importance for verifying the inherent safety characteristics of high temperature gas-cooled reactor (HTGR). The 10 MW HTGR, designed by Tsinghua University, is exampled to be analyzed in this paper. The accident scenarios of a double-ended guillotine rupture at inlet and outlet of a heat-exchange tube are simulated respectively by RELAP5/MOD3.2. The results show that both water ingress mass and the rupture flow rate are significantly related to the rupture location. The draining system rapidly discharged water from the SG, mitigating effectively the accident consequences. Due to thermal inertia, the coolant inside the average tube refluxes and surges out of the rupture, so it is essential to consider the measures for the timely evacuation of the average tube.

Waterproofing integrity and water tightness of buildings in the tropic

For tropical countries in Southeast Asia, frequent heavy rains and the local habit of using lots of water in wet areas such as toilets and bathrooms within dwelling units are the major reasons that waterproofing designs fail to prevent the water ingress into buildings. Unfortunately, not many studies on the effectiveness of waterproofing system for such climatic conditions and social habits have been reported. Results of studies conducted on various categories of defects related to water ingress and water tightness for public housing projects and others buildings in Singapore are reported. Examination of waterproofing failures in Singapore and other Southeast Asia countries showed the cause of the failure was because the waterproofing designs adopted were mainly copied from developed temperate countries in the earlier years. Based on the causes of waterproofing failures, revised details are proposed for tropical countries with frequent heavy rains and similar social habits to eliminate these failures in an integrated approach, that is, design, construction, and maintenance, to achieve efficiency, durability, ease of construction and maintenance, overall quality assurance, and cost effectiveness for the waterproofing system. Revised details adopted to achieve waterproofing integrity and water tightness of conventional and prefabricated buildings in the tropic are presented.

Development of a new soil–structure contact stress sensor for underground construction applications

This paper describes the design, development, calibration and validation of a novel soil–structure contact stress sensor. The new sensor design combines a novel operating principle, fibre Bragg grating (FBG) strain sensing and data-driven mapping techniques to create a multi-axis contact stress sensor that is both economical and suitably robust for deployment in underground construction applications. The instrumentation process is informed using a ‘virtual twin’ of the sensor in which synthetic data is generated by extracting and interpolating virtual FBG strains obtained from a large number of 3D finite-element calculations. A physical prototype is subsequently developed to demonstrate proof of concept. Results from laboratory validation tests give confidence in the sensor's ability to provide accurate contact stress measurements in typical soil–structure interface shear applications. In particular, the novel sensor structure and operating principle was shown to achieve excellent measurement of effective normal stress. The new sensor design harnesses many of the inherent benefits of FBGs including immunity to electromagnetic noise and water ingress, and the use a single lightweight cable and connector, which significantly simplifies installation on site compared to electrical multi-axis sensors.

Mechanical behavior of water ingress process for the locally damaged submerged floating tunnel and its interpretation: A full-length experimental study

The submerged floating tunnel (SFT) is an innovative transportation solution for traversing deep-water regions. However, local damage and subsequent water ingress pose significant threats to the structural integrity and safety of SFTs. This critical issue has been unexplored in the field. This study addresses this gap by presenting a comprehensive experimental investigation using a full-length physical model of the SFT. The dynamic response and failure mechanisms caused by water ingress within the SFT tube, influenced by various factors such as immersion depth, damaged opening angle, damaged opening area, and external connectivity, are systematically investigated. The results indicate that the failure of the anchor cable and tube structure of the SFT progresses through three stages after water ingress occurs in the damaged SFT. It is observed that damage closer to the bottom of the tube reduces the risk of failure in the mooring system. Notably, air pressure is a critical factor influencing the water ingress into the tube body. The attenuation of cable tension and tube deformation is significantly slower when the internal air is isolated from the external environment. The proposed novel structural sealing segmental disaster prevention design scheme substantially mitigates the risk of structural damage under compromised conditions and water ingress. This study provides valuable insights into enhancing disaster prevention strategies for SFTs and advances the understanding of their mechanical behavior in response to damage and water ingress.

Hydrogeological Resolution Using Composite Geophysical Methods: A Case Study of Inland Salinity in Part of Agra, Uttar Pradesh India

ABSTRACT This manuscript is an attempt at utilizing a combination of varied Geophysical methods (n = 4) – Vertical Electrical Sounding (VES), Electrical Resistivity Tomography (ERT), Time Domain Electromagnetic (TEM), and Borehole logging for finer resolution of potential fresh groundwater and saline groundwater aquifer zones in marginal alluvial plains of Agra district, Uttar Pradesh state. A conceptual model of sub-surface aquifer disposition displaying zones of fresh and saline groundwater zones was prepared using an interpreted and processed multi-parameter dataset. A positive correlation was found between TEM (44.6 m), Well log data (43.0 m), VES data (47.2), and ERT data (45.0 m) demarcating the boundary up to which fresh groundwater potential lies from the ground surface. Conventional methods rely on resistivity values to identify groundwater potential zones, and a rough estimation of salinity can be carried out. Instead of the conventional VES method, the combination of aforesaid methods results in finer resolution and easier demarcation of fresh groundwater zones from those of saline zones. This method can be successfully reproduced to demarcate the extent of saline water ingress in coastal areas and finding freshwater lenses within inland saline aquifers.