Groundwater quantity and quality may be affected by climate change through intricate direct and indirect mechanisms. At the same time, population growth and rapid urbanization have made groundwater ...an increasingly important source of water for multiple uses around the world, including southern Africa. The present study investigates the coupled human and natural system (CHANS) linking climate, sanitation, and groundwater quality in Ramotswa, a rapidly growing peri-urban area in the semi-arid southeastern Botswana, which relies on the transboundary Ramotswa aquifer for water supply. Analysis of long-term rainfall records indicated that droughts like the one in 2013–2016 are increasing in likelihood in the area due to climate change. Key informant interviews showed that due to the drought, people increasingly used pit latrines rather than flush toilets. Nitrate, fecal coliforms, and caffeine analyses of Ramotswa groundwater revealed that human waste leaching from pit latrines is the likely source of nitrate pollution. The results in conjunction indicate critical indirect linkages between climate change, sanitation, groundwater quality, and water security in the area. Improved sanitation, groundwater protection and remediation, and local water treatment would enhance reliable access to water, de-couple the community from reliance on surface water and associated water shortage risks, and help prevent transboundary tension over the shared aquifer.
Water Supply and Water Scarcity Tzanakakis, Vasileios A.; Paranychianakis, Nikolaos V.; Angelakis, Andreas N.
Water (Basel),
2020, Letnik:
12, Številka:
9
Journal Article
Recenzirano
Odprti dostop
This paper provides an overview of the Special Issue on water supply and water scarcity. The papers selected for publication include review papers on water history, on water management issues under ...water scarcity regimes, on rainwater harvesting, on water quality and degradation, and on climatic variability impacts on water resources. Overall, the issue underscores the need for a revised water management, especially in areas with demographic change and climate vulnerability towards sustainable and secure water supply. Moreover, general guidelines and possible solutions, such as the adoption of advanced technological solutions and practices that improve water use efficiency and the use of alternative (non-conventional) water resources are highlighted and discussed to address growing environmental and health issues and to reduce the emerging conflicts among water users.
Population growth, economic development, and dietary changes have drastically increased the demand for food and water. The resulting expansion of irrigated agriculture into semi-arid areas with ...limited precipitation and surface water has greatly increased the dependence of irrigated crops on groundwater withdrawal. Also, the increasing number of people living in mega-cities without access to clean surface water or piped drinking water has drastically increased urban groundwater use. The result of these trends has been the steady increase of the use of non-renewable groundwater resources and associated high rates of aquifer depletion around the globe. We present a comprehensive review of the state-of-the-art in research on non-renewable groundwater use and groundwater depletion. We start with a section defining the concepts of non-renewable groundwater, fossil groundwater and groundwater depletion and place these concepts in a hydrogeological perspective. We pay particular attention to the interaction between groundwater withdrawal, recharge and surface water which is critical to understanding sustainable groundwater withdrawal. We provide an overview of methods that have been used to estimate groundwater depletion, followed by an extensive review of global and regional depletion estimates, the adverse impacts of groundwater depletion and the hydroeconomics of groundwater use. We end this review with an outlook for future research based on main research gaps and challenges identified. This review shows that both the estimates of current depletion rates and the future availability of non-renewable groundwater are highly uncertain and that considerable data and research challenges need to be overcome if we hope to reduce this uncertainty in the near future.
Nitrogen pollution of groundwater is becoming more and more serious due to intense and extensive industrial and agricultural activities. This may exert great influence on human health. In this paper, ...human health risk due to groundwater nitrogen pollution in Jinghui canal irrigation area in Shaanxi Province of China where agricultural activities are intense was assessed. Forty-seven groundwater samples were collected from shallow wells and analyzed for physicochemical indices in the study area. Water samples were analyzed for pH, total dissolved solids (TDS), total hardness (TH), major ions (Na
+
, K
+
, Ca
2+
, Mg
2+
, HCO
3−
, CO
3
2−
, Cl
−
and SO
4
2−
), nitrate (NO
3
–N), nitrite (NO
2
–N) and ammonia nitrogen (NH
4
–N). General groundwater chemistry was described by statistical analysis and the Piper diagram. Water quality was quantified via comprehensive water quality index (CWQI), and human health risk was assessed considering the age and exposure pathways of the consumers. The results show that the shallow groundwater is slightly alkaline and groundwater types are HCO
3
·SO
4
·Cl–Mg and HCO
3
·SO
4
·Cl–Na. Rock weathering and evaporation are main natural processes regulating the groundwater chemistry. The CWQI indicates that groundwater in the study area is seriously polluted by TH, TDS, SO
4
2−
, Cl
−
and NO
3
−
. Human health risk is high because of high concentrations of nitrate in drinking water. The results also show that children are at higher risk than adults. The health risk through dermal contact is much lower than that through drinking water intake and can be ignored.
Climate change has a pronounced effect on water resources in many semiarid climates, causing populated areas such as San Diego County (USA), to become more vulnerable to water shortages in the coming ...decades. To prepare for decreased water supply, San Diego County is adopting policies to decrease water use and to develop additional local sources of water. One new local source of freshwater is produced by a desalination facility that purifies brackish groundwater from the coastal San Diego Formation. This formation has been studied extensively onshore, but little is known about the geology or groundwater quality offshore in the adjacent continental shelf. Because most groundwater systems are interconnected and complex, further analysis is needed to identify offshore geology, possible sequestration of freshwater in the shelf, and potential pathways for saltwater intrusion. This comprehensive understanding is important because seawater intrusion may limit use of the San Diego Formation and longevity of desalination facilities. Controlled-source electromagnetic methods are uniquely suited to detecting offshore groundwater as they are sensitive to changes in pore fluids such as the transition from fresh to brackish groundwater. This paper describes results from surface-towed electromagnetic surveys that mapped the pore-fluid salinity and possible fluid pathways in the continental shelf off the coast of San Diego. The results indicate a considerable volume of fresh-to-brackish groundwater sequestered in the shelf, both in continuous lenses and isolated pockets, that appear influenced by fault systems and shallow stratigraphy.
Crete, located in the South Mediterranean Sea, is characterized by long coastal areas, varied terrain relief and geology, and great spatial and inter-annual variations in precipitation. Under average ...meteorological conditions, the island is water-sufficient (967 mm precipitation; theoretical water potential 3425.89 hm3; and total water use 610 hm3). Agriculture is by far the greatest user of water (78% of total water use), followed by domestic use (21%). Despite the high average water availability, water scarcity events commonly occur, particularly in the eastern-south part of the island, driven by local climatic conditions and seasonal or geographical mismatches between water availability and demand. Other critical issues in water management include the over-exploitation of groundwater, accounting for 93% of the water used in agriculture; low water use efficiencies in the farms; limited use of non-conventional water sources (effluent reuse); lack of modern frameworks of control and monitoring; and inadequate cooperation among stakeholders. These deficiencies impact adversely water use efficiency, deteriorate quality of water resources, increase competition for water and water pricing, and impair agriculture and environment. Moreover, the water-limited areas may display low adaptation potential to climate variability and face increased risks for the human-managed and natural ecosystems. The development of appropriate water governance frameworks that promote the development of integrated water management plans and allow concurrently flexibility to account for local differentiations in social-economic favors is urgently needed to achieve efficient water management and to improve the adaptation to the changing climatic conditions. Specific corrective actions may include use of alternative water sources (e.g., treated effluent and brackish water), implementation of efficient water use practices, re-formation of pricing policy, efficient control and monitoring, and investment in research and innovation to support the above actions. It is necessary to strengthen the links across stakeholders (e.g., farmers, enterprises, corporations, institutes, universities, agencies, and public authorities), along with an effective and updated governance framework to address the critical issues in water management, facilitate knowledge transfer, and promote the efficient use of non-conventional water resources.
The Gulf Cooperation Council (GCC) countries are located in the driest part of the world with an annual per capita water availability of 500 m3 compared to the world average of 6000 m3. Agricultural ...water demand, which is more than 80% of the total water consumption, is primarily met through the massive exploitation of groundwater. The enormous imbalance between groundwater discharge (27.8 billion m3) and recharge (5.3 billion m3) is causing the excessive lowering of groundwater levels. Therefore, GCC countries are investing heavily in the production of nonconventional water resources such as desalination of seawater and treated wastewater. Currently, 439 desalination plants are annually producing 5.75 billion m3 of desalinated water in the GCC countries. The annual wastewater collection is about 4.0 billion m3, of which 73% is treated with the help of 300 wastewater treatment plants. Despite extreme water poverty, only 39% of the treated wastewater is reused, and the remaining is discharged into the sea. The treated wastewater (TWW) is used for the landscape, forestry, and construction industries. However, its reuse to irrigate food and forage crops is restricted due to health, social, religious, and environmental concerns. Substantial research evidence exists that treated wastewater can safely be used to grow food and forage crops under the agroclimatic conditions of the GCC countries by adopting appropriate management measures. Therefore, GCC countries should work on increasing the use of TWW in the agriculture sector. Increased use of TWW in agriculture can significantly reduce the pressure on freshwater resources. For this purpose, a comprehensive awareness campaign needs to be initiated to address the social and religious concerns of farming communities and consumers. Several internal and external risks can jeopardize the sustainable use of treated wastewater in the GCC countries. These include climate change, increasing costs, technological and market-driven changes, and regional security issues. Therefore, effective response mechanisms should be developed to mitigate future risks and threats. For this purpose, an integrated approach involving all concerned local and regional stakeholders needs to be adopted.
An ecosystem in freefall, a shrinking water supply for cities and agriculture, an antiquated network of failure-prone levees—this is the Sacramento-San Joaquin Delta, the major hub of California's ...water system. Written by a team of independent water experts, this analysis of the latest data evaluates proposed solutions to the Delta's myriad problems. Through in-depth economic and ecological analysis, the authors find that the current policy of channeling water exports through the Delta is not sustainable for any interest. Employing a peripheral canal-conveying water around the Delta instead of through it—as part of a larger habitat and water management plan appears to be the best strategy to maintain both a high-quality water supply and at the same time improve conditions for native fish and wildlife. This important assessment includes integrated analysis of long term ecosystem and water management options and demonstrates how issues such as climate change and sustainability will shape the future. Published in cooperation with the Public Policy Institute of California
In this paper, the spatial distribution of fluoride (F
‒
) and manganese (Mn) in groundwater was described and the overall groundwater quality was assessed with the entropy weight water quality index ...(EWQI) in Weining Plain, northwest China. The probabilistic health risk of F
‒
and Mn in groundwater was assessed by the Monte Carlo stochastic simulation method. The results show that 50 groundwater samples (a total of 144) belong to poor and very poor quality because of agricultural activities, industrial development, and the local hydrogeological conditions. Groundwater quality in the upper reaches of the Yellow River is better than that in the lower reaches. The average health risks faced by children and adults are 4.59 and 0.62, respectively. If the uncertainty of the model parameters are considered, the mean risks faced by children and adults are 6.84 and 0.92, respectively, indicating that the health risk to residents, especially children, cannot be ignored. Compared with dermal contact, drinking water intake is the main exposure way to harm residents’ health. F
‒
contributed higher to the health risk than Mn, and children face greater risk than adults. Stochastic simulation can reflect health risks more comprehensively than the deterministic methods. The study results are helpful for decision makers to take measures for the safe supply of drinking water in the study area.
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