Impacts of Salt on Water Resources

Impacts of Salt on Water Re radicalsIntroduction. brininess, one of the study wet crises elapsering around the globe, is the exalted con centration of positive dissolved solids (TDS), such(prenominal) as sodium and chlorine, in soils and wet (Rose, 2004). brininess is a fine and prevalent task affecting Australia, threatening the Australian natural surroundings and the sustainability of w arive rural theatre of operationss (Bridg universe, Dragovish, Dodson, 2008 McDowell, 2008). This back be attributed to naturally utmoster(prenominal) saline levels in the soils (McDowell, 2008 Pannell, 2001). Across the globe, in countries such as in America, Iran, Pakistan, India and China, life-size concentrations of common brininess accept accumulated oer time collectable to rainfall, oscillate weathering, sea urine intrusion and aerosol deposits (Table 1) (Beresford et al., 2001 Hlsebusch et al., 2007). Dry impart coarseness, a course of action of alter primordi al coarseness, has particularly become a study problem world-wide (Beresford et al., 2001). Annually, about four million hectares of global farmland is abandoned payable to excessive salt (Beresford et al., 2001). table salt is a widespread problem with numerous major social, economic and environmental consequences (Beresford et al., 2001).OutlineThis paper will dish out the concomitant and impacts of special and indirect salt on water resources. The questionion will commence by focusing on primary salinity, its fleetrence and associated impacts using an example from the Lake Eyre Basin, Australia. The next part of the essay will discuss secondary salinity, its occurrence and impacts using examples from Katanning Western Australia (WA) and Turkey. Iran and Pakistan will whence be examined as examples showing the occurrence and impacts of both primary and secondary salinity. in the end the impacts of salinity will be identified and the main arguments of this account s ummarised. treatmentPrimary salinityPrimary salinity is a natural appendage that affects soils and waters and occurs generally in component parts of the world where rainfall is insufficient to withdraw salts from the soil and vaporization or transpiration is high (McDowell, 2008). In episodes of high evaporation, transpiration and cut back rainfall, salinity becomes a problem as the volume of water decreases date salt concentrations plus (Bridgman, Dragovish, Dodson, 2008). Approximately 1000 million hectares, which corresponds to seven per cent of the worlds total land area, is stirred to many extent by salt (Rose, 2004). The majority of the globes saline alter land is influence by primary salinity resulting from natural soil evolution (Hlsebusch et al., 2007). arid tropical areas, in particular, are subject to potential evaporation that is higher(prenominal) than rainfall, which transmits to the rising of water to the topsoil where solutes accumulate and salinity pot entiometer occur naturally (Hlsebusch et al., 2007). Australias waterless and semi- waterless areas usually have salt present in the groundwater (Table 2) (Bridgman, Dragovish, Dodson, 2008). For example, the River dearie becomes saline during harsh drought periods and salinity concentrations make up in the Hunter valley when flow diminishes (Bridgman, Dragovish, Dodson, 2008).Lake Eyre Basin, sulfur AustraliaThe Lake Eyre Basin (LEB), in central Australia, is a grownuply like a shot area dominated by semi-arid to arid environmental conditions (Figure 1) (McMahon et al., 2008). The area encounters high evaporation rates and spatially and temporally highly versatile rainfall (Kingsford Porter, 1993). Year round, potential evaporation is usually great than developed evaporation with average y primaeval Class A pan evaporation rates of 3300 milli cadencys (mm) (Costelloe et al., 2008). Average yearly rainfall in the LEB ranges from less than 200mm in some areas, up to 700 mm in separates, with an annual coefficient of variability spanning from 0.2 to 0.7 (McMahon et al., 2008). Hydrological conditions in the LEB stinkpot vary between prolonged periods of 18 to24 months of no flow, to shorter phases where inundation of slow floods can occur (Costelloe et al., 2008). The portioning of the stable isotopes of water such as d16O/ d18O can be utilised to determine whether evaporation (enriching/fractionation occurs) or transpiration (no fractionation) occurs (Costelloe et al., 2008). In Lake Eyre, the water is sodium and chlorine ion dominated with salinity varying from approximately 25 300 mg L-1 and 272 800 mg L-1 (Kingsford Porter, 1993). The absence of invertebrates and waterbirds in Lake Eyre is model to be due to salinity from change magnitude evaporation during the dry months (Kingsford Porter, 1993). This salinity is similarly said to be responsible for massive fish kills that occur as the lake dries after a flood period (Kingsford Porter, 1993). Samples taken in the LEB showed that there was greater enrichment of the isotopic signatures of the erupt water than the groundwater samples, a product of high rates of evaporation (Costelloe et al., 2008). The Diamantina River catchment, a major contributor of pepperflow to Lake Eyre, was name to have hypersaline, 85,000 mg L-1 Cl, rest pools in the channel, with a highly enriched isotopic signature, indicating evaporation (Costelloe et al., 2008). The Neales River catchment in the LEB demonstrated extremely saline groundwater (71,000 mg L-1 Cl) and hypersaline residual pools of 130,000-150,000 mg L-1 Cl (Costelloe et al., 2008). petty(a) SalinitySecondary salinity is caused by man made changes to the hydrological cycle either through the replacement of native plant life with shallow-rooted phytology or through the excessive use or uneffective distribution of water in irrigation for agriculture (Beresford et al., 2001 Rose, 2004). Modern anthropogenic land-use pract ices are change magnitude the area of salt-affected land, which is a major environmental issue (Bridgman, Dragovish, Dodson, 2008). Estimates of secondary salinity affecting the globe are suggested at around 74 million hectares, with 43 million hectares of that land occurring on irrigated land and the stay area on non-irrigated land (Rose, 2004). In Australia, areas of the Murray Basin and the Mallee region in Victoria (VIC) and New South Wales (NSW) are affected by dryland and irrigation salinity, season irrigation salinity impacts the Riverina Plain in VIC and NSW and the Riverland Region in South Australia (Beresford et al., 2001).Dryland SalinityDryland salinity is the resultant change in subsurface hydrology in which native vegetation with deeper roots are replaced by shallow-rooted vegetation, such as unsophisticated crops (Rose, 2004). This cover causes a decrease in annual evaporation and an increase in the amount of water reaching the water table (Bridgman, Dragovish, Dodson, 2008). The proceed rise in the amount of water available can thence lead to saline water reaching the soil surface and vegetation (Rose, 2004). When this saline water intersects or reaches the surface, waterlogging and salinization of the surface soil can occur due to the accumulation of salts (Rose, 2004). There is an estimated lag time of 30 to 50 years between vegetation clearance and the emergence of salinity (Bridgman, Dragovish, Dodson, 2008). about a third of the areas in Australia that are susceptible to dryland salinity are expected to become saline (Figure 2) (Rose, 2004). Dryland salinity has impacted North and South Dakota in Northern America and the Canadian Western Prairies due to immense scale husk farming in which there is now increasing loss of productivity and rising death rates in a variety of wildlife (Beresford et al., 2001). India, Thailand, Argentina, and South Africa are some of the other countries that experience problems with dryland salinity (Pannell Ewing, 2006).Katanning District, WAIn the Katanning district, abundant clearing of native vegetation has lead to the area universe reported as having one of the worst salinity problems in WA (Beresford et al., 2001). The township is located in a low, flat part of the landscape, and is agriculturally centred on crops, such as wheat and canola, and sheep (Figure 3) (Beresford et al., 2001). The initial unfailing vegetation, generally of Mallee associations, has been removed and replaced with the aforementioned crops (Bridgman, Dragovish, Dodson, 2008). Following 1891, there was increased wheat cultivation in the district and land clearing (Beresford et al., 2001). In the early 1900s, the increase of salt in nearby natural water sources was rapidly linked to the clearing of native vegetation (Beresford et al., 2001). In 2000, records of the Katanning Creek Catchment showed that altogether 1000 hectares of remnant vegetation remained translating to less than 10 per cen t of the catchment being covered (Beresford et al., 2001). It was also discovered in 2000 that 125 hectares of land neighbouring the town boundary was salt affected, the water table was less than one metre from the surface in some areas and older infrastructure were showing testify of salt-induced decay (Beresford et al., 2001). Groundwater under the township is influenced by the subsurface flow from catchments where extensive land clearing has occurred (Beresford et al., 2001). Dryland salinity in Australia will continue to increase unless farming systems are dramatically altered on a large scale (Rose, 2004).Irrigation SalinityThe application of irrigation can increase salinity levels in soil water, surface water systems and/or aquifers (Van Weert, Van der Gun, Reckman, 2009). Irrigation can also raise water tables, lead to waterlogging, and cause evaporation directly from the water table, increasing solute concentration in the soil (Van Weert, Van der Gun, Reckman, 2009). Arou nd the world, the greater part of anthropogenic salinity is associated with irrigated rather than non-irrigated land (Bridgman, Dragovish, Dodson, 2008). A higher amount of land in Australia that is non-irrigated, rather than irrigated, however, is salt-affected (Pannell Ewing, 2006). Bridgman, Dragovish, Dodson (2008) stated that irrigated areas that have their water table within two metres of the soil surface are salinized. Agriculture, in which irrigation systems are utilized, is especially prone to salinization with approximately half of the irrigation systems globally affected by salinization, alkalization or waterlogging (Munns, 2002). Countries particularly affected by irrigation salinity accommodate Egypt, China, Pakistan, Iran, India, and Argentina (Hlsebusch et al., 2007).Sanliurfa-Harran Plain TurkeyTurkey faces salinity problems due to big and intensive irrigation, such as in the Harran Plain (Van Weert, Van der Gun, Reckman, 2009). only when 25 percent, or 19.3 million hectares, of Turkeys land surface is usable for agricultural practices, three percent of which is affected by salinity (Atis, 2006). The main source of soil salinity has resulted from the adverse effects of irrigation water, leading to the formation of high water tables resulting in decreased agricultural productivity and income (Atis, 2006). The Sanliurfa-Harran Plain region is located in an arid and semi-arid climate (Kendirli, Cakmak, Ucar, 2005). In this area, high levels of total dissolved solids have emerged in the shallow groundwater due to excessive and wild irrigation, waterlogging, rising water tables, and drainage problems (Van Weert, Van der Gun, Reckman, 2009). Prior to the implementation of irrigation in the central and southern parts of the Harran Plain, salinity and drainage problems already existed, which were then exacerbated when irrigation was applied (Table 3) (Kendirli, Cakmak, Ucar, 2005). It was estimated over fifty percent of productive agricultu ral land in the Akcakale Groundwater Irrigations area of the Harran Plain was becoming saline after irrigation, some 5000 hectares (Kendirli, Cakmak, Ucar, 2005). In the towns of Harran and Akcakale, within the Sanliurfa-Harran Plain, increased salinity problems and high saline and sodium soils were attributed to public irrigation (Kendirli, Cakmak, Ucar, 2005). Within the Sanliurfa-Harran Plain, over 29 percent of soils examined were becoming saline following irrigation (Kendirli, Cakmak, Ucar, 2005).Combined SalinityIn Iran and Pakistan, the salinization of land resources is a major problem due to a combination of primary salinity and secondary salinity (Kahlown et al., 2003 Qadir, Qureshi, Cheraghi, 2008). Thirty per cent of Irans irrigated area and 26.2 per cent of Pakistans are staidly affected by irrigation salinity, much of which may need abandoning (Kendirli, Cakmak, Ucar, 2005 Hlsebusch et al., 2007). Iran and Pakistan mainly endure arid and semi-arid environmental co nditions (Kahlown et al., 2003 Qadir, Qureshi, Cheraghi, 2008). Annually, rainfall nationally averages 250mm in Iran, patch average yearly potential evaporation is extremely high, varying from 700mm to over 4000mm (Qadir, Qureshi, Cheraghi, 2008). Approximately 34 million hectares in Iran are salt-affected (Qadir, Qureshi, Cheraghi, 2008). In the blue area of Iran, slight to moderate salt-affected soils exist, where as highly saline soils are present in the central areas (Figure 4) (Qadir, Qureshi, Cheraghi, 2008). Primary salinity in Iran is a result of a combination of factors including the geologic composition of the soils parent material, such as halite and gypsum, natural salinization of surface waters due to stream salinity, salinity and the expansion of salinity from wind-borne origins, seawater intrusion, low rainfall and high potential evapotranspiration (Qadir, Qureshi, Cheraghi, 2008). Secondary salinity has been a result of irrigation with saline waters, lacking( p) drainage, unsustainable groundwater pumping, saline aquifer over-exploitation, excessive irrigation and overgrazing (Qadir, Qureshi, Cheraghi, 2008). Some 4.2 million hectares in Pakistan are poorly affected by irrigation salinity (Hlsebusch et al., 2007). Salinization of soils and water in Pakistan are a result of natural climatic characteristics, such as high evaporation, geological conditions and the dissolution of salt bearing strata, waterlogging, intensive irrigation, poor drainage, salinity ingress, ineffectual irrigation and inappropriate use of low calibre groundwater (Kahlown et al., 2003 Van Weert, Van der Gun, Reckman, 2009). general soil and water salinization in Iran and Pakistan has occurred due to varied combinations of these factors (Kahlown et al., 2003 Qadir, Qureshi, Cheraghi, 2008).ImpactsSalinity can cause tree die back, changes in ecosystems, loss of productive lands, salt bush growth, erosion, saline groundwater discharge and saline surface water (Be resford et al., 2001 Bridgman, Dragovish, Dodson, 2008). The groundwater that rises as a result of dryland salinity can contain relatively high amounts of salts which results in saline seepages emerging where the water table intersects the ground surface (Bridgman, Dragovish, Dodson, 2008). If concentrations of sodium ions are high enough, the physical structure of soils may be completely degraded from salinity (McDowell, 2008). This is due to the collapse of soil aggregates and deflocculation of remains particles compaction then occurs and causes decreased permeability and porosity which restricts water stock as well as slowing internal drainage (McDowell, 2008). Salinity can result in the deterioration of river and stream quality, for example, in the Murray Darling River system in SA, the town of Morgans water quality is expected to go the desirable drinking limit of 500 mg L 1 total soluble salts within the next ninety years (Pannell Ewing, 2006). operose salt-affected wa ter can move to surface water systems, infiltrate downstairs the root zone or may reach an aquifer and contribute to a progressive increase in salinity of groundwater, decreasing the water quality (Van Weert, Van der Gun, Reckman, 2009). There can be a greater insecurity of large-scale water quality problems due to an increase in safety valve of saline waters from the impacted region (McDowell, 2008). Increased flood risks have also been identified as an impact of dryland salinity as a result of shallower water tables which can lead to at least a two-fold increase in flood flows (Pannell Ewing, 2006).ConclusionsSalinity is a major problem throughout the world, particularly in arid and semi-arid environmental climates. Primary salinity is a natural phenomenon that affects soils and waters in periods of high evaporation, transpiration, and low rainfall. This process occurs notably in Australia, as well as many other countries, such as Iran and Pakistan. Secondary salinity is huma n induced from either land clearing or irrigation. Numerous countries experience dryland salinity, such as North America, India, Canada, Thailand, Argentina, and South Africa, as well as Australia. Countries that are affected by irrigation salinity include Egypt, Australia, China, Pakistan, Iran, Turkey, India, and Argentina. 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