447 research outputs found

    Urmia Lake Watershed Restoration in Iran: Short- and Long-Term Perspectives

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    Urmia Lake (also known as Oroumieh Lake) is a shallow terminal lake located in northwest Iran and one of the largest permanent lakes in the Middle East. Due to its biodiversity it has been designated as a Biosphere Reserve by UNESCO and a National Park under the 1971 Ramsar Convention. At present, the entire lakeā€™s watershed is threatened due to drought and abrupt decline of the lakeā€™s water level and the consequent increase of salinity. The rapidly declining eco-environmental conditions have serious impacts on the socio-economy of the whole region. In this paper we review the environmental state of art and suggest measures to improve the lakeā€™s ecology by short- and long-term restoration possibilities. There are indications that the hydrology of the area could be described by a chaotic climate and a low-dimensional dynamical system. However, also the human impact is strong due to mismanagement of water resources. It is concluded that a multidisciplinary integrated approach is needed to tackle the current critical situation

    Integrated Watershed Management to Save the UNESCO Biosphere Reserve Lake Urmia, Iran

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    Lake Urmia is a hypersaline lake in northwest Iran. Due to its unique aquatic ecosystem it has been designated as a Biosphere Reserve by UNESCO and a National Park under the 1971 Ramsar Convention. The biodiversity of the lake is determined by its salinity and Artemia urmiana is the dominant invertebrate and also the key element of the lakeā€™s food chain. The lake is relatively shallow and satellite data indicate that the water level has plummeted during the last 17 years due to a dramatic decline in surface water inflow and consequent increase in salinity of the lake (from 166 g/L in 1995 to about 340 g/L in 2008). Thus, the entire lakeā€™s ecology is threatened. The lake represents about 7% of the total surface water in Iran. About 20 permanent and periodic rivers together with other episodic streams are flowing into the lake. These rivers along with precipitation are the major sources of inflow and evaporation is the main outflow from this endorheic lake. In view of the above, the main objective of this paper was to review the state of art of knowledge for the threatened lake and to suggest possible solutions to improve the lakeĀ“s ecology. Hydrological and hydraulic data for the area are quite limited with short records. Many previous studies, using the same data records, have arrived at quite different management options to restore the lakeĀ“s ecology. The fundamental reason for the threatened lakeĀ“s ecology appears to be the lack of sustainable management. The paper evaluates different management options and their environmental impact. Through a multidisciplinary integrated approach, possible short-term and long-term solutions are presented to manage the lakeĀ“s ecology and reach a sustainable watershed management through a lake restoration project. Suggested integrated watershed management includes consideration of population growth and water demand, cloud seeding and rainwater harvesting, freshwater inflow to the lake and improved irrigation methods, efficient salt industry, establishing a waste water treatment plant and developing tourism industry as a source of income. Further hydrological modeling studies are needed to study the combined effect of climate change and dam construction. The paper is closed by discussing practical implications of the study and scaling-up possibilities

    Steady-State Unconfined Aquifer Simulation of the Gareh-Bygone Plain, Iran : Steady-State Unconfined Aquifer Simulation

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    The first step of aquifer parameter and dependent variable estimation based on hydraulic modeling is generally to choose the best steady-state condition for the set time period. In order to define the best estimated hydraulic conductivity and boundary condition for Gareh-Bygone Plain in arid southern Iran, ten different steady-state conditions were simulated and calibrated with limited field observations. The investigated area covers about 6000 ha with a floodwater spreading system that was established on about 2000 ha to artificially recharge the groundwater. The results showed a consistency over the 14-year simulation period with estimated hydraulic conductivity in a quite narrow range. This makes us believe that even if the modeling problem is to some extent over-parameterized the results appear quite robust. This is further strengthened by verification of the model results. Furthermore, the results showed that in the steady-state groundwater flow with no recharge from surface water, the system is mainly recharged by the fault which conducts water into the area from an upper sub-basin

    A Joint Desalination and Power Plants for Water and Development: A Case study of the Sinai-Gaza

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    Desalination can be a cost-effective way to produce fresh water and possibly electricity. The Gaza Strip has had a complex hydro-political situation for many years. Gaza (enclosed area) is bordered by the Mediterranean in the west, by Israel in the north and east and by Egypt in the south. Water and electricity consumption in the Gaza Strip is expected to increase in the future due to the increasing population. In this paper, a solution for Sinai and the Gaza Strip is suggested involving the building of a joint power and desalination plant, located in Egypt close to the border of Gaza. Results of capital and unit costs have been derived from bench-mark studies of 18 different desalination projects mainly in the Middle East countries. The suggested joint Egypt-Palestine project would increases drinking water supply by 500,000 m3/d and the power supply by 500MW, whereof 2/3 is suggested to be used in Gaza and 1/3 in Sinai. The present lack of electricity and water in Gaza could be erased by such a project. But Egypt will probably gain more. More water and electricity will be available for the future development of Sinai; a significant value will be added to the sale of Egyptian natural gas used for water and power production in the project; more employment opportunities can be offered for people living in Sinai and Gaza; the domestic market for operation and maintenance of desalination plants can be boosted by the suggested project. Egypt may naturally and peacefully increase its cooperation with and presence in Gaza, which should lead to increased security around the border between Egypt and Gaza. This type of project could also get international support and can be a role-model for cooperation and trust-building between neighbours in the Middle East region. This study have also compared with more than five different alternatives

    Substantial carbon sequestration by peatlands in temperate areas revealed by InSAR

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    Peatlands are unique ecosystems that contain massive amounts of carbon. These ecosystems are incredibly vulnerable to human disturbance and climate change. This may cause the peatland carbon sink to shift to a carbon source. A change in the carbon storage of peatlands may result in surface deformation. This research uses the interferometric synthetic aperture radar (InSAR) technique to measure the deformation of the peatland's surface in south Sweden in response to the seasonal and extreme weather conditions in recent years, including the unprecedented severe drought in the summer of 2018. The deformation map of the study area is generated through a time-series analysis of InSAR from June 2017 to November 2020. Monitoring the peatland areas in this region is very important as agricultural and human activities have already caused many peatlands to disappear. This further emphasizes the importance of preserving the remaining peat sites in this region. Based on the InSAR results, a method for calculating the carbon flux of the peat areas is proposed, which can be utilized as a regular monitoring approach for other remote areas. Despite the severe drought in the summer of 2018, our findings reveal a significant uplift in most of the investigated peat areas during the study period. Based on our estimations, 86% of the peatlands in the study area experienced an uplift corresponding to about 47 000 tons of carbon uptake per year. In comparison, the remaining 14% showed either subsidence or stable conditions corresponding to about 2300 tons of carbon emission per year during the study period. This emphasizes the importance of InSAR as an efficient and accurate technique to monitor the deformation rate of peatlands, which have a vital role in the global carbon cycle

    Spatial Characteristics of Groundwater Chemistry in Unzen, Nagasaki, Japan

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    Nitrate pollution in groundwater is a serious problem in Shimabara Peninsula, Nagasaki, Japan. A better understanding of the hydrogeochemical evolution of groundwater in vulnerable aquifers is important for health and environment. In this study, groundwater samples were collected at 12 residential and 57 municipal water supply wells and springs in July and August 2018. Nitrate (NO3-N) concentration at eight sampling sites (12%) exceeded Japanese drinking water standard for NO3 + NO2-N (10 mg L-1). The highest nitrate concentration was 19.9 mg L-1. Polluted groundwater is distributed in northeastern, northwestern, and southwestern areas, where land is used for intensive agriculture. Correlation analysis suggests that nitrate sources are agricultural fertilizers and livestock waste. Dominant groundwater chemistry is (Ca+Mg)-HCO3 or (Ca+Mg)-(SO4+NO3) type. Groundwater with higher nitrate concentration is of (Ca+Mg)-(SO4+NO3) type, indicating nitrate pollution affecting water chemistry. Principal component analysis extracted two important factors controlling water chemistry. The first principal component explained dissolved ions through water-rock interaction and agricultural activities. The second principal component explained cation exchange and dominant agricultural effects from fertilizers. Hierarchical cluster analysis classified groundwater into four groups. One of these is related to the dissolution of major ions. The other three represent nitrate pollution

    Spatiotemporal variation of nitrate concentrations in soil and groundwater of an intensely polluted agricultural area

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    Nitrate pollution in groundwater is a serious problem in many parts of the world. However, due to the diffuse and common spatially over-lapping character of potential several non-point pollution sources, it is often difficult to distinguish main nitrate sources responsible for the pollution. For this purpose, we present a novel methodology applied to groundwater for an intensely polluted area. Groundwater samples were collected monthly from April 2017 to March 2018 in Shimabara City, Nagasaki, Japan. Soil samples were collected seasonally at soil surface and 50 cm depth at 10 locations during the same period. Sequential extraction by water and extract agents was performed using calcium phosphate for anions and strontium chloride for cations. Mean nitrate concentration in groundwater close to a livestock waste disposal site (hereinafter called ā€œLWDSā€) was 14.2 mg Lāˆ’1, which is exceeding Japanese drinking water standards (10 mg Lāˆ’1). We used coprostanol concentration, which is a fecal pollution indicator, to identify pollution sources related to livestock waste. For this purpose, we measured coprostanol (5Ī²) and cholestanol (5Ī±) and then calculated the sterol ratio (5Ī²/(5Ī² + 5Ī±)). The ratios for three groundwater sampling sites were 0.28, 0.26, and 0.10, respectively. The sterol ratios indicated no pollution (< 0.3). However, the detection of coprostanol originating from animal and human waste showed that groundwater was clearly affected by this pollution source. Nitrate levels in the soil were relatively high in samples collected close to the LWDS and coprostanol contents were affected by livestock waste. Soil and groundwater nitrate concentrations displayed a complex but strong relationship. Nitrate contents were shown to be transported downstream from source areas in both soil and groundwater

    Simulating river flow to the Baltic Sea from climate simulations over the past millennium

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    The aim of this study was to reconstruct river flow to the Baltic Sea using data from different periods during the past thousand years. A hydrological model coupled to simulations from climate models was used to estimate river flow. A "millennium" simulation of past climate from the ECHO-G coupled atmosphere-ocean global climate model provided climatological inputs. Results from this global model were downscaled with the RCA3 regional climate model over northern Europe. Temperature and precipitation from the downscaled simulation results were then used in the HBV hydrological model to simulate river flows to the Baltic Sea for the periods 1000-1199 and 1551-1929. These were compared with observations for the period 1921-2002. A general conclusion from this work is that although climate has varied during the past millennium, variability in annual river flow to the Baltic Sea does not appear more pronounced in recent years than during the previous millennium, or vice versa

    PFAS in the Drinking Water Source: Analysis of the Contamination Levels, Origin and Emission Rates

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    Groundwater contamination caused by the use of the aqueous film-forming foam (AFFF) containing per- and polyfluoroalkyl substances (PFAS) was investigated in southern Sweden. sigma PFAS concentrations in groundwater ranged between 20 and 20,000 ng L-1; PFAS composition was primarily represented by PFOS and PFHxS. The PFAS chain length was suggested to have an impact on the contaminant distribution and transport in the groundwater. PFAS profiling showed that the use of PFSAs- and PFCAs/FTSAs-based PFAS-AFFF can be a contributor to PFAS contamination of the drinking water source (groundwater). PFAS emission was connected to PFAS-AFFF use during the fire-training and fire-fighting equipment tests at the studied location. PFAS emission per individual fire training was (semi-quantitatively) estimated as [1.4 < 11.5 +/- 5.7 < 43.7 kg] (n = 20,000). The annual emission estimates varied as [11 < 401 +/- 233 < 1125 kg yr(-1)] (n = 1005) considering possible [2 < 35 +/- 20 < 96] individual fire-training sessions per year
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