Saltwater intrusion refers to the process by which sea water infiltrates coastal groundwater systems, thus mixing with the local freshwater supply. Conclusion salt water intrusion into aquifers in the coastal sedimentary basins in nigeria has occurred. Saltwater intrusion into the coastal aquifer, a phenomenon brought by the flow of seawater into freshwater aquifers originally caused by groundwater extraction near the coast, has long been recognised as a major concern around the world. There is vital need to monitor the feasible risk of saline water intrusion of the coastal aquifers because, once saline intrusion into coastal aquifer has occurred, it is extremely. Intrusion of seawater into coastal aquifers is considered one of the most important processes that degrade water quality by raising the salinity to levels exceeding acceptable drinking standards. Saltwater intrusion ce le le fresh ground water fresh ground water ocean pumped well well discharge land surface saline ground water saline ground water a b figure 25. Introduction in response to the rapid increase of water demand for the town of port lincoln, south australia from 0. Apr 20, 2016 furthermore, the solutions that have been usually adopted in the fight against saline intrusion, are rather inappropriate to the semiarid zones of europe. Seawater intrusion associated with lowering of groundwater levels is an important issue in many of californias coastal groundwater basins. Between 1968 and 1971, about 45 km2 of coastal land was subject to water quality degradation because of landward movement of the freshwatersaltwater interface and upward vertical intrusion of deeper saline groundwater.
Tidal influence on seawater intrusion in unconfined coastal. The excessive pumping of groundwater, associated with the lack of natural recharge, has exacerbated the swi problem in arid and semiarid regions. This determines a new hydrostatic equilibrium between freshwater and saltwater. A costeffective method to control seawater intrusion in. Groundwater is stored in the pores and fractures of rock beneath the surface, and the rock. The induced gradients usually cause migration of salt water from the sea toward a borehole where groundwater. Mapping of the fresh water salt water interfaces in most of the coastal aquifers is. View enhanced pdf access article on wiley online library html view.
Tidal influence on seawater intrusion in unconfined coastal aquifers woei keong kuan,1,2 guangqiu jin,3 pei xin,1 clare robinson,4 badin gibbes,5 and ling li1,3 received 16 march 2011. Saline water intrusion in coastal aquifers of orissa, india. Pdf saline water intrusion into coastal aquifers dr. Geophysical investigation of saline water intrusion into. This paper brings to the fore techniques for proper management of saline water intrusion in coastal region because of the hardship its negligence bring upon the public that rely on it for livelihood. Unexpected mistreatment of groundwater from coastal aquifers may possibly cause salt water intrusion in coastal aquifers. The depth of the freshwater saline water interface using hydraulic heads in the coastal aquifer near beihai, chinam was estimated by zhou 2011. In this study, we employed geophysical and geochemical techniques to map and provide evidences that the coastal aquifers in the study area have been intruded. Therefore, appropriate management strategies should be. Geophysical methods are used to identify seawater intrusion based on resistivity values. A case study from bangladesh international organization of scientific research 9 p a g e figure. Management of saltwater intrusion in coastal aquifers in. Seawater intrusion can jeopardise the groundwater resources for coastal communities such as those living in the gaza strip, putting them at risk of waterborne diseases.
Seawater intrusion in coastal aquifers concepts, methods. Pdf study on saline water intrusion into the shallow. This has been observed in the miami, florida, area where the gradient of the water table is low, but the aquifer is very permeable and fresh water is constantly discharged into biscayne bay. This paper presents a costeffective method to control seawater intrusion in coasta. Assessment of potential seawater intrusion in a coastal. Abstract the dispersion of salts produced by reciprocative motion of the salt water front in a coastal aquifer induces a flow of salt water from the floor of sea into the zone of diffusion and back to the sea. Seawater intrusion in coastal aquifers download ebook. The continued reliance on ground water has resulted in its decline in quantity and quality. Risk of saltwater intrusion in coastal bedrock aquifers. Another is to recharge water reserves in technically strategic coastal zones. Seawater intrusion generally occurs when withdrawal of fresh groundwater from coastal aquifers results in declining groundwater levels, facilitating lateral andor vertical migration of saline water causing deterioration of groundwater quality. Coastal aquifers constitute a vital source of fresh water in these regions, and are increasingly used to meet the water supply needs pareek et al. Pdf saline water intrusion in coastal aquifers of orissa. This problem affects the potability of the water and the population.
To prevent saltwater intrusion, some of the rules for well drilling should be followed. The confined aquifers in most parts of the delta contain fresh water underlain by salt water. Seawater intrusion swi is one of the most challenging and widespread environmental problems that threaten the quality and sustainability of fresh groundwater resources in coastal aquifers. Seawater intrusion directly threatens the entral oasts economy, where many highvalue, salt sensitive crops, such as strawberries, are grown. Seawater intrusion sgma usgs ca water science center. Well location at least 50 m from the coast well depth avoid deep. Saltwater intrusion is the induced flow of seawater into freshwater aquifers primarily caused by groundwater development near the coast. Water samples collected along the coastal region were subjected to various physico chemical analyses. Where groundwater is being pumped from aquifers that are in hydraulic connection with the sea, induced gradients may cause the migration of salt water from the sea toward a well, making the freshwater well unusable. A twodimensional representation of an unconfined coastal aquifer. The induced gradients usually cause migration of salt water from the sea toward a. A in coastal areas, fresh ground water discharges to. Saltwater intrusion into coastal aquifers in nigeria. Management of seawater intrusion in coastal aquifers.
The salinity of the pumped water has been analysed periodically and it has been found that the threat of saltwater intrusion is emerging due to the. The conference is designed to bring together scientists, engineers, water resource managers, and policy makers who are actively involved in andor affected by salt water intrusion, management of coastal aquifers, and submarine groundwater discharge. Geological survey usgs uses data collection, modeling tools, and scientific analysis to help water managers plan for, and assess, hydrologic issues that can cause undesirable results associated with groundwater use. Modelling of groundwater pumping scenarios and their impact. Introduction saltwater intrusion is defined as the replacement of fresh water in coastal aquifers by saltwater due to the motion of a saltwater body into the freshwater aquifer. Research open access mapping saline water intrusion into. Saltwater intrusion occurs when saline salty water is drawn into a freshwater aquifer. Mapping saline water intrusion into the coastal aquifer. As sea water intrusion progresses, existing pumping wells, especially those close to the coast, become saline. They introduced the sharp interface model known as the ghybenherzberg relationship which is based on the hydrostatic balance between fresh and saline water in a ushaped tube. Three dimensional simulation of seawater intrusion in. Assessment of groundwater quality and saline intrusions in. Fuentes florida international university, department of civil and environmental engineering,10555 w. The primary focus of the plan is on stabilizing or halting the intrusion of salt water into the upper floridan aquifer, which is a dominant water supply source shared by coastal georgia and neighboring areas of south carolina and florida.
Of fresh water and salt water in a coastal aquifer by hilton h. Field and modeling studies were started to consider the special effects of possible seawater intrusion into the coastal aquifers. Saltwater intrusion can affect one well, or multiple wells in an aquifer, making the water unpotable unpleasant to drink. Mapping saline water intrusion into the coastal aquifer with. Remote detection of saline intrusion in a coastal aquifer. When pumping occurs, only a part of the freshwater recharge discharges to the sea. Geophysical investigation, saline water, aquifers, coastal terrain. Modeling impact of saline intrusion on freshwater of a. In this study, the coastal aquifers of lagos metropolis were selected for an assessment of its groundwater quality and impact of saline intrusion. Pdf hydrogeological investigation on saline water intrusion.
Water samples collected along the coastal region were subjected to various physicochemical analyses. Research open access mapping saline water intrusion into the. Saltwater intrusion can naturally occur in coastal aquifers, owing to the hydraulic connection between groundwater and seawater. In certain zones of the delta however, salt water intrusion into the confined aquifers has occurred with salt water bearing sands overlying fresh water. Level rise on salt water intrusion near a coastal well field in southeastern florida. The intrusion occurs as a result of the induced flow of seawater into freshwater aquifers originally caused by groundwater development around the coast al barwani and helmi, 2006. Saline intrusion on a coastal aquifer medcrave online. The selected area is an agricultural region located on a coastal aquifer where the groundwater is being consumed continuously as the main water source for drinking, greenhouses and industries.
Because saline water has a higher mineral content than freshwater, it is denser. Saltwater intrusion into the coastal aquifer has long been recognised as a major concern around the world. Proceedings of the institution of civil engineers water. The declining water level has caused a significant level in saline water intrusion which reflects the rise in salinity content of the groundwater along a coastal aquifer. Ground water pumping can reduce freshwater flow toward coastal discharge areas and cause saltwater to be drawn toward the freshwater zones of the aquifer. Remedial measures for saline water ingression in coastal. Pdf mapping saline water intrusion into the coastal. Seawater intrusion and how to prevent it the water. Modeling saline water intrusion in nagapattinam coastal. Geophysical study of saline water intrusion in lagos municipality. Saltwater intrusion is the movement of saline water into freshwater aquifers, which can lead to groundwater quality degradation, including drinking water sources, and other consequences. In many coastal aquifers, intrusion of seawater has become one of the major constraints imposed on groundwater utilization. The plan recognizes that actions taken to halt the intrusion of additional salt water into the aquifer will.
The first quantitative approach to determine saltwater depth in coastal aquifers was developed independently by badon ghijben 1888 and herzberg 1901. Saltwater intrusion solinst groundwater and surface water. The risk of saline intrusion clearly limits the extent to which a coastal aquifer can be developed for water supply but the proportion of the infiltration that can be used can be increased by skilful management. Best practices for prevention of saltwater intrusion. As sea water intrusion progresses, existing pumping wells, especially those close to the coast, become saline and have to be abandoned. The dense seawater typically circulates inland through the sediments or rock, creating a saline zone or wedge below the less dense overlying freshwater aquifer figure 1. Optimal management of a coastal aquifer under saline intrusion. The best management of seawater intrusion would be to apply desalination technology and improve the efficiency of existing waste water treatment plants for water recycling and subsequent reuse. The induced gradients usually cause migration of salt water from the sea toward a borehole. Water free fulltext management of seawater intrusion in. As seawater moves into an aquifer it causes severe water quality impacts, which can result in saline groundwater that is unsuitable for irrigation or domestic use. Best practices for prevention of saltwater intrusion author. Saline intrusion represents one of the most persistent environmental problems at the worldwide coasts.
Ground water quality can be adversely affected or degraded as a result of hu man activities that introduce contamination into the environment. Coastal areas are mostly overpopulated with productive agricultural lands and expanded irrigated farming actions. Thus it is seen that the influence of saline water into coastal freshwater aquifer depends on the height of ground water level above the sea level. One of the factors affecting the quality of water from this source is saline water intrusion, especially in coastal aquifers. Schematic of aquifer stratigraphy in the coastal zone of bangladesh ravenscroft and mcarthur, 2004 pliocene to holocene sediments are extensively tapped to supply drinking water and the majority of. Saltwater intrusion decreases freshwater storage in the aquifers, and, in extreme cases, can result in the abandonment of supply wells. Seawater intrusion and groundwater resources management in. Flagler street, ec 3671, miami, fl 33174,usa email. Vinogradov1,4 1department of earth science and engineering, imperial college london, london, uk, 2department of civil and environmental engineering, imperial college london, london, uk, 3now at. Mapping saline water intrusion into the coastal aquifer with geophysical and geochemical techniques. True picture of the quality of sea water intrusion are shown in figure 2 by using flow lines and potential lines. Pdf saline intrusion on a coastal aquifer researchgate. An aquifer thickness of 2025 m is observed near the coast where the vulnerability ranking is the highest. Saltwater intrusion reduces the available fresh groundwater resour.
Typically, changes on the hydrological cycle are associated to urbanization of recharge areas and changes on the natural surface and. During periods of heavy recharge in shallow coastal aquifers, the salt water fresh water boundary moves toward the sea. Saltwater intrusion in the surficial aquifer system of the big cypress basin, southwest florida, and a proposed plan for improved salinity monitoring. Water supply management modeling impact of saline intrusion on freshwater of a coastal aquifer yonas t. Saltwater intrusion has occurred to some degree in many of the coastal aquifers of the united states. Many studies in coastal aquifers have focused on sea water intrusion as the source of highsalinity groundwater, and the process and mechanism of sea water intrusion are well understood richter and kreitler 1993. Jul 07, 2010 the selected area is an agricultural region located on a coastal aquifer where the groundwater is being consumed continuously as the main water source for drinking, greenhouses and industries. Whereas the interior portion has less than 5 m of aquifer thickness, and the lowest vulnerability ranking of 2. The thickness of the aquifer is directly proportional to salt water intrusion potential in the region.
Analysis of saline intrusion into a coastal aquifer. The installation of drainage canals, poorly cased wells, and water supply withdrawals have led to saltwater intrusion in the primary water use aquifers in southwest florida. Since saltwater cannot be used to irrigate crops or be consumed by people, saltwater intrusion can be very problematic to coastal communities that rely on fresh groundwater supplies for the livelihood. Sea water intrusion abstract severe sea water intrusion can be detected several kilometers inland and represents a high risk for coastal region groundwater. Resistivity values are indirectly proportional to the conductivity of the groundwater. In industrial and coastal location, th e saline water intrusion resulted in contamination of the potable ground water aquifers. Furthermore, the solutions that have been usually adopted in the fight against saline intrusion, are rather inappropriate to the semiarid zones of europe. Lateral intrusion of sea water because of overpumpming from the wells deeper saline water movement due to to upconing near coastal wells. Hydrogeological investigation on saline water intrusion into a coastal aquifer of west bengal, india. The coastal aquifer of the continental terminal of the township of abomeycalavi benin has been highly exploited for intensive drinking water capture to supply the most important cities. Therefore saltwater intrusion should be prevented or at least controlled to protect groundwater resources. Seawater intrusion into the coastal aquifer in the gaza strip. The most common technique is to increase the groundwater flow from the aquifers to the sea.
1386 1471 1392 777 662 681 112 1450 1081 721 1406 619 965 823 696 1279 243 806 389 1547 709 847 233 128 233 1030 508 1022 316 1056 348 477