GRACE a witness to the Recovery of the Tigris-Euphrates Hydrologic System

2020 ◽  
Author(s):  
Mohamed Sultan ◽  
Karem Abdelmohsen ◽  
Himanshu Save
Keyword(s):  
Surface Water ◽  
Land Surface ◽  
Global Precipitation Climatology Project ◽  
Water Levels ◽  
Dry Period ◽  
The Past ◽  
Grace Data ◽  
Precipitation Record ◽  
The World ◽  
Precipitation Events

<p>Global warming is producing climatic changes across the world that affect in major ways the livelihood of major sectors of the world’s population. Over the past decade or two, an increase in the frequency and intensity of specific climatic phenomena (e.g., hurricanes, wet or dry periods, etc.) has been reported from many parts of the globe and is believed to be climate change-related. Over the past few years, the largest and most intense precipitation events were recorded over the Tigris and Euphrates watershed (TEW), a heavily engineered watershed (> 60 main dams) that is shared by Turkey, Iran, Syria, Saudi Arabia, and Iraq. Analysis of the Global Precipitation Climatology Project (GPCP) precipitation record over the past 40 year (1979-present) across the TEW revealed a prolonged dry period (2002- to 2017; Average Annual Precipitation [AAP]: 240 km<sup>3</sup>), followed by wet years (2018 to 2020; AAP: 425 km<sup>3</sup>). The recent extensive precipitation events during the wet period are reflected in GRACE and GRACE-FO data. Throughout the dry period there was a total decline in GRACE<sub>TWS</sub> of 212 km<sup>3</sup> (13.3 km<sup>3</sup>/yr) followed by an increase of 246 km<sup>3</sup> (82 km<sup>3</sup>/yr) during the wet period.  In other words, in the past 2.5 years, the TEW more than recovered its losses during the previous 15 years. This recovery was enabled in part by the impoundment of surface water behind the many dams in the riparian countries and by infiltration of precipitation that recharged the TEW aquifers. Using radar altimetry we observe an increase in surface water levels by 8 m in Lake Ataturk, 13 m in Lake Karakaya, 1.5 m in Lake Van in Turkey, 5 m in Lake Assad in Syria, and 16 m in Lake Tharthar, and 24 m in Lake Mosul in Iraq.  These translate to a volume increase of 21.7 km<sup>3</sup> in Turkey, 3.5 km<sup>3</sup> in Syria, and 34 km<sup>3</sup> in Iraq during the wet period. Using GRACE data and outputs of land surface models, we estimate that groundwater storage GRACE<sub>TWS</sub> declined at a rate of -7 km<sup>3</sup>/yr during the dry period and increased at a rate of 60 km<sup>3</sup>/yr during the wet years.</p>

The Vyredox and Nitredox Methods of in situ Treatment of Groundwater

1988 ◽  
Vol 20 (3) ◽  
pp. 149-163 ◽  
Author(s):  
Carol Braester ◽  
Rudolf Martinell
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Traditional Method ◽  
Treatment Method ◽  
Nitrate Treatment ◽  
The Past ◽  
The World ◽  
Nitrate And Nitrite ◽  
Iron And Manganese

Nearly one fifth of all water used in the world is obtained from groundwater. The protection of water has become a high priority goal. During the last decades pollution of water has become more and more severe. Today groundwater is more and more used in comparison with surface water. Recently we have seen accidents, which can pollute nearly all surface water very quickly. Generally the groundwater is easier to protect, as well as cheaper to purify, and above all it is of better quality than the surface water. During the past two decades, alternatives to the traditional method of treating the water in filters have been developed, that is in situ water treatment i.e. the VYREDOX and NITREDOX methods. The most common problem regarding groundwater is too high content of iron and manganese, which can be reduced with the VYREDOX method. In some areas today there are severe problems with pollution by hydrocarbons and nitrate as well, and with modification of the VYREDOX treatment method it is used for hydrocarbon and nitrate treatment as well. The method to reduce the nitrate and nitrite is known as the NITREDOX method.

scholarly journals Hydrogeology of Brahmaputra Basin, India

2003 ◽  
Vol 28 ◽  
Author(s):  
Barendra Purkait
Keyword(s):  
Ground Water ◽  
Water Table ◽  
Land Surface ◽  
Flood Plain ◽  
Water Levels ◽  
The South ◽  
Drainage Pattern ◽  
The North ◽  
The World ◽  
Brahmaputra Basin

The Ganga-Brahmaputra river system together forms one of the largest deltas in the world comprising some 59570 sq km. The waterpower resources of the Brahmaputra have been presumed to be the fourth biggest in the world being 19.83 x 103 m3s1. The entire lower portion of the Brahmaputra consists of a vast network of distributary channels, which are dry in the cold season but are inundated during monsoon. The catchment area of the entire river is about 580,000 sq km, out of which 195,000 sq km lies in India. The maximum discharge as measured at Pandu in 1962 was of the order of 72800 m3 s-1 while the minimum was 1750 m3 s-1 in 1968. The drainage pattern in the valley is of antecedent type while the yazoo drainage pattern is most significant over the composite flood plain to the south of the Brahmaputra. The Brahmaputra valley is covered by Recent alluvium throughout its stretch except a few isolated sedimentary hills in the upper Assam, inselbergs/bornhardt of gneissic hills in the Darrang, Kamrup and Goalpara districts and a few inlying patches of Older Alluvium in the Darrang and Goalpara districts. The basin is very unstable. The present configuration of the basin is the result of uplift and subsidence of the Precambrian crystalline landmasses. Four geotectonic provinces can be delineated in the N-E India through which the Brahmaputra flows. These are bounded by major tectonic lineaments such as the basement E-W trending Dauki fault, a NE-SW trending structural feature of imbricate thrusts known as 'belt of Schuppen' and the NW-SE trending Mishmi thrust. Hydrogeologically, the Brahmaputra basin can be divided into two distinct categories, viz(a) dissected alluvial plain and (b) the inselberg zone. The first category is rep resented in the flood plain extending from the south of Sub-Himalayan piedmont fan zone in the north to right upto the main rock promontory of Garo Hills and Shillong Plateau. The inselberg zone is characterized by fractured, jointed and weathered ancient crystalline rocks with interhill narrow valley plains, consisting of thin to occasionally thick piles of assorted sediments. From the subsurface lithological data, two broad groups of aquifers are identified. These are i) shallow water table and ii) deeper water table or confined ones, separated by a system of aquicludes. The shallow aquifer materials, in general, consist of white to greyish white, fine grained micaceous sand and the thickness ranges from 1.2 to 10.3 m. The sand and clay ratio varies from 1: 2.5 to 1:26. The bedrock occurs at depth ranges of 30.4 to 39.5 m. The materials of the deeper aquifers comprise grey to greyish white, fine to medium grained sand. The sand and clay ratio varies from 1:2 to 1:7. The effective size of the aquifer materials varies from 0.125 to 0.062 mm with uniformity co-efficient around 4.00, porosity 38 to 42%, co-efficient of permeability 304 to 390 galls per day/0.3m2. The ground water is mildly alkaline with pH value 6.5 to 8.5, chloride 10 to 40 ppm, bi-carbonate 50 to 350 ppm, iron content ranges from a fraction of a ppm to 50 ppm. Total dissolved solids are low, hardness as CaCo3 50 to 300 ppm, specific conductance at 25 °C 150 to 650 mhos/cm. The yield from shallow aquifers is 1440 litres to 33750 litres/hour and for deeper aquifers ~ 1700 litres/hour at a drawdown of 13.41 m, specific capacity 21 litres/minute. The temperatures of ground water are 23°-25° C during winter, 24°-26° C during pre-monsoon and 27°- 28° C during peak monsoon. The general hydraulic gradient in the north bank is 1:800 whereas in the south bank it is 1: 300-400 The Tertiary sediments yield a range of water from 200 to 300 l.p.m whereas the yield from the Older Alluvium is 500 to 700 1.p.m. The estimated transmissibility and co-efficient of storage is of the order of ~ 800 1.p.m/ m and 8.2 x 10-3 respectively. Depths to water levels range from 5.3 to 10m below land surface (b.l.s). In the Younger or Newer Alluvium, ground water occurs both under water table and confined conditions. Depths to water levels vary from ground level to 10 m b.l.s. Depth to water ranges from 6 m b.l.s. to 2 m above land surface. The yield of the deep tubewells ranges from 2 to 4 kl/minute for a drawdown of 3 m to 6 m. The transmissibility of the aquifers varies from 69 to 1600 l.p.m/m and the storage co-fficient is of the order of 3.52 x 10-2.

Global Overview of Tropical Dry Forests

2020 ◽  
pp. 1-23
Author(s):  
G. N. Tanjina Hasnat ◽  
Mohammed Kamal Hossain
Keyword(s):  
Climate Change ◽  
Endangered Species ◽  
Land Surface ◽  
Forest Type ◽  
Conservation Status ◽  
Tropical Dry Forests ◽  
Land Conversion ◽  
Dry Period ◽  
Dry Forests ◽  
The World

Forests cover almost one-third of the Earth's land surface. Tropical dry forests are the second-most-important forest type in the world covering approximately 42% of tropical and sub-tropical forest area. The main features of these forests are their deciduousness, a prolonged dry period extending 3-9 months, and little annual precipitation of 250-2,000 mm. Tropical dry forests are found in five of the eight realms in the world. More than half of the forests are distributed in the Americas, with other portions in Africa, Eurasia, Australia, and Southeast Asia. The forests are unique in nature, and provide shelter to a huge number of endemics and endangered species. Among woody plant species, about 40% are not found anywhere in the world. These forests are now the most threatened among all forest types. The conservation status of these forests is endangered. Deforestation, rapid civilization, land conversion, fire, and climate change are the major threats. Proper management with time-oriented policy could be helpful to restore these forests and protect the existing remnant areas.

scholarly journals Prevalence of pesticides in Krško-Brežice polje aquifer

Geologija ◽  
2021 ◽  
Vol 64 (2) ◽  
pp. 267-288
Author(s):  
Nina MALI ◽  
Anja KOROŠA ◽  
Janko URBANC
Keyword(s):  
Surface Water ◽  
Passive Sampling ◽  
Sampling Method ◽  
Agricultural Land ◽  
Plant Protection ◽  
Degradation Products ◽  
Plant Protection Products ◽  
The Past ◽  
Groundwater Samples ◽  
The World

Groundwater pollution with pesticides is a problem that occurs all over the world as well as in Slovenia. Considering the past high loads of groundwater with pesticides, the purpose of the presented research was to determine the presence of pesticides in the groundwater of Krško-Brežiško polje in the period 2018-2019 and to check the applicability of the passive sampling method. A total of 21 groundwater samples were taken at 11 locations and 2 samples each in the Sava and Krka rivers. We identified 15 pesticides and their degradation products. Atrazine and its degradation product desethylatrazine were most frequently determined in groundwater samples. They are followed by desethylterbutylazine, terbutylazine, metolachlor and simazine. Atrazine, desethylatrazine, chlortoluron, metolachlor and terbuthylazine were detected in surface water. A total of 24 samples were taken in groundwater and surface water using the qualitative passive sampling method. We singled out 8 pesticides that appear in two campaigns. The frequency and occurrence of individual pesticides by both methods are comparable. Passive sampling has proven to be an appropriate method of identifying the presence of pesticides. The highest loads in the Krško-Brežiško field arise from the agricultural land areas. Groundwater is more contaminated with pesticides in the central part of the field in the direction of groundwater flow from west to east. In the groundwater of the Krško-Brežice field, atrazine and desethylatrazine are still the most frequently detected pesticides with higher concentrations, despite a 20 years long ban on the use of atrazine-based plant protection products.

scholarly journals A generic method for hydrological drought identification across different climate regions

2012 ◽  
Vol 16 (8) ◽  
pp. 2437-2451 ◽  
Author(s):  
M. H. J. van Huijgevoort ◽  
P. Hazenberg ◽  
H. A. J. van Lanen ◽  
R. Uijlenhoet
Keyword(s):  
Land Surface ◽  
Threshold Level ◽  
Global Scale ◽  
Hydrological Drought ◽  
Dry Period ◽  
Drought Duration ◽  
Variable Threshold ◽  
The World ◽  
Level Method ◽  
Zero Runoff

Abstract. The identification of hydrological drought at global scale has received considerable attention during the last decade. However, climate-induced variation in runoff across the world makes such analyses rather complicated. This especially holds for the drier regions of the world (both cold and warm), where, for a considerable period of time, zero runoff can be observed. In the current paper, we present a method that enables to identify drought at global scale across climate regimes in a consistent manner. The method combines the characteristics of the classical variable threshold level method that is best applicable in regions with non-zero runoff most of the time, and the consecutive dry days (period) method that is better suited for areas where zero runoff occurs. The newly presented method allows a drought in periods with runoff to continue in the following period without runoff. The method is demonstrated by identifying droughts from discharge observations of four rivers situated within different climate regimes, as well as from simulated runoff data at global scale obtained from an ensemble of five different land surface models. The identified drought events obtained by the new approach are compared to those resulting from application of the variable threshold level method or the consecutive dry period method separately. Results show that, in general, for drier regions, the threshold level method overestimates drought duration, because zero runoff periods are included in a drought, according to the definition used within this method. The consecutive dry period method underestimates drought occurrence, since it cannot identify droughts for periods with runoff. The developed method especially shows its relevance in transitional areas, because, in wetter regions, results are identical to the classical threshold level method. By combining both methods, the new method is able to identify single drought events that occur during positive and zero runoff periods, leading to a more realistic global drought characterization, especially within drier environments.

scholarly journals An Analysis of Regional Snow Assessments at Selected Hydrological Stations on the Danube and Tisza Rivers

2013 ◽  
Vol 21 (3) ◽  
pp. 43-56
Author(s):  
Beáta Hamar Zsideková ◽  
Balázs Gauzer ◽  
Gábor Bálint
Keyword(s):  
Surface Water ◽  
Water Balance ◽  
Land Surface ◽  
Hydrological Cycle ◽  
Time Lag ◽  
Precipitation Event ◽  
Seasonal Forecasts ◽  
The Earth ◽  
Precipitation Record ◽  
The Relationship

Abstract Precipitation falling on a land surface is one of the most important elements of the hydrological cycle, and it is the only input term of the water balance on the Earth´s surface. On those areas of the Earth where a part of the annual precipitation falls in the form of snow, the rhythm of the hydrological cycle, i.e., the water balance within a year, follows a pattern that deviates from that of the precipitation record. Precipitation falling in a solid state enters the hydrological cycle with a time lag that might be as much as several months after the precipitation event. Therefore, instead of considering the observed values of precipitation when describing the various elements of the hydrological cycle, it is more expedient to take the surface water input into account. This is a fraction of the precipitation which is present on the land surface in a liquid state. Consequently, the most important task of the various snow models within the rainfall - runoff and water budget schemes is to transform the precipitation values observed into surface water input values. Spring time runoff largely depends on the snowmelt component, and it gives the possibility of estimating the expected seasonal volume of the flow and flood peaks. Seasonal forecasts based on the relationship between snow resources and expected precipitation during the spring months have been analyzed for the Danube and Tisza rivers.

scholarly journals A Study on Iot Based Flood Detection Management System

2021 ◽  
Vol 10 (4) ◽  
pp. 130-133
Author(s):  
C.K. Gomathy ◽  
Priya, G G Lasya ◽  
Hemanth Kumar
Keyword(s):  
Mobile App ◽  
Water Levels ◽  
The Internet ◽  
Time Data ◽  
The Past ◽  
The People ◽  
The World ◽  
Flood Detection ◽  
The Internet Of Things ◽  
Different Parts

Over the past few years we can see there is an occurrence of floods at different parts of the world almost every year. The technical advancements in recent years have made it easier to get a solution for these natural disasters. One of such technologies which takes us much closer to the internet is the “Internet of Things”. This paper consists of flood detection and avoidance system using the iot technology. The sensors present in this are used to estimate the water levels, humidity, and temperature and send the real-time data to the cloud and the users can access the data via the mobile app. This model is widely used to alarm the people before a flood occurs and necessary precautions could be taken.

Groundwater modelling for time periods of up to hundreds of thousands of years.

2020 ◽  
Author(s):  
Gerrit H. de Rooij ◽  
Thomas Mueller
Keyword(s):  
Surface Water ◽  
Water Level ◽  
Coastal Plain ◽  
Land Surface ◽  
Hydraulic Head ◽  
Water Levels ◽  
Analytical Models ◽  
Time Interval ◽  
Mountain Range ◽  
Time Step

<p>Occasionally, there is an interest in groundwater flows over many millennia. The input parameter requirement of numerical groundwater flow models and their calculation times limit their usefulness for such studies.</p><p>Analytical models require considerable simplifications of the properties and geometry of aquifers and of the forcings. On the other hand, they do not appear to have an inherent limitation on the duration of the simulated period. The simplest models have explicit solutions, meaning that the hydraulic head at a given time and location can be calculated directly, without the need to incrementally iterate through the entire preceding time period like their numerical counterparts.</p><p>We developed an analytical solution for a simple aquifer geometry: a strip aquifer between a no flow boundary and a body of surface water with a prescribed water level. This simplicity permitted flexible forcings: The non-uniform initial hydraulic head in the aquifer is arbitrary and the surface water level can vary arbitrarily with time. Aquifer recharge must be uniform in space but can also vary arbitrarily with time.</p><p>We also developed a modification that verifies after prescribed and constant time intervals if the hydraulic head is such that the land surface is covered with water. This excess water then infiltrates in areas where the groundwater level is below the surface and the remainder is discharged into the surface water. The hydraulic head across the aquifer is modified accordingly and used as the initial condition for the next time interval. This modification models the development of a river network during dry periods. The increased flexibility of the model comes at the price of the need to go through the entire simulation period one time step at a time. For very long time records, these intervals will typically be one year.</p><p>Given the uncertainty of the aquifer parameters and the forcings, the models are expected to be used in a stochastic framework. We are therefore working on a shell that accepts multiple values for each parameter as well as multiple scenarios of surface water levels and groundwater recharge rates, along with an estimate of their probabilities. The shell will generate all possible resulting combinations, the number of which can easily exceed 10000, then runs the model for each combination, and computes statistics of the average hydraulic head and the aquifer discharge into the surface water at user-specified times.</p><p>A case study will tell if this endeavor is viable. We will model the aquifer below the mountain range north of Salalah in Oman, which separates the desert of the Arabian Peninsula from the coastal plain at its southern shore. Rainfall estimates from the isotopic composition of stalactites in the area indicate distinct dry and wet periods in the past 300 000 years. In combination with estimated sea level fluctuations over that period, this provides an interesting combination of forcings. We examine the dynamics of the total amount of water stored in the aquifer, and of the outflow of water from the aquifer into the coastal plain.</p>

scholarly journals A generic method for hydrological drought identification across different climate regions

2012 ◽  
Vol 9 (2) ◽  
pp. 2033-2070 ◽  
Author(s):  
M. H. J. van Huijgevoort ◽  
P. Hazenberg ◽  
H. A. J. van Lanen ◽  
R. Uijlenhoet
Keyword(s):  
Land Surface ◽  
Threshold Level ◽  
Global Scale ◽  
Hydrological Drought ◽  
Dry Period ◽  
Drought Duration ◽  
Variable Threshold ◽  
The World ◽  
Level Method ◽  
Zero Runoff

Abstract. The identification of hydrological drought at global scale has received considerable attention during the last decade. However, climate-induced variation in runoff across the world makes such analyses rather complicated. This especially holds for the drier regions of the world (both cold and warm), where for a considerable period of time, zero runoff can be observed. In the current paper, we present a method that enables to identify drought at global scale across climate regimes in a consistent manner. The method combines the characteristics of the classical variable threshold level method that is best applicable in regions with non zero runoff most of the time, and the consecutive dry days (period) method that is better suited for areas where zero runoff occurs. The newly presented method allows a drought in periods with runoff to continue in the following period without runoff. The method was demonstrated by identifying droughts from discharge observations of four rivers situated within different climate regimes, as well as from simulated runoff data at global scale obtained from an ensemble of five different land surface models. The identified drought events obtained by the new approach were compared to those resulting from application of the variable threshold level method or the consecutive dry period method separately. Results show that, in general, for drier regions, the threshold level method overestimates drought duration, because zero runoff periods were included in a drought, according to the definition used within this method. The consecutive dry period method underestimates drought occurrence, since it cannot identify droughts for periods with runoff. The developed method especially shows its relevance in transitional areas, because in wetter regions, results were identical to the classical threshold level method. By combining both methods, the new method is able to identify single drought events that occur during positive and zero runoff periods, leading to a more realistic global drought characterization, especially within drier environments.

scholarly journals SIMULASI SUMUR RESAPAN BERDASARKAN ANALISIS PERBANDINGAN KETINGGIAN AIR BANJIR DI KELAPA GADING JAKARTA

2020 ◽  
Vol 3 (3) ◽  
pp. 797
Author(s):  
Lionel Felix ◽  
Gregorius Sandjaja Sentosa
Keyword(s):  
Surface Water ◽  
Rainfall Intensity ◽  
Shallow Groundwater ◽  
Extreme Rainfall ◽  
Water Levels ◽  
Extreme Conditions ◽  
Drainage Channel ◽  
Entire Volume ◽  
Flood Water ◽  
The Past

Flooding has been a problem for the past few decades in Jakarta. The flooding in early January 2020 was one of the worst floods since 2013. One of the most severely affected areas was Kelapa Gading. To find a solution, infiltration wells are used. Infiltration well is a simple conservation in the form of a container that is built in the soil that functions to accommodate, hold and absorb surface water into the soil to increase the amount and position of the ground water level. The analysis begins by calculating the rainfall intensity from the January 2020 rainfall data, proceeding with the calculation of rainwater discharge with USSCS rational method, and calculation of the volume of water entering and not entering the drainage channel. This analysis focuses on flood water levels due to extreme rainfall, to then design infiltration wells. Analysis using the program is done after getting the results of manual calculations. The results of this analysis conclude that millions of infiltration wells are needed to absorb entire volume of flood water. This is due to the shallow groundwater and extreme conditions of rainfall.  Banjir sudah menjadi masalah selama beberapa dekade terakhir di Jakarta. Banjir pada awal Januari 2020 adalah salah satu banjir terparah sejak tahun 2013. Salah satu daerah yang paling terdampak adalah Kelapa Gading. Untuk mencari solusi banjir, digunakan sumur resapan. Sumur resapan adalah konservasi sederhana berupa wadah yang dibangun ke dalam tanah yang berfungsi menampung, menahan dan meresapkan air ke dalam tanah untuk meningkatkan muka air tanah. Analisis dimulai dengan menghitung intensitas hujan dari data curah hujan Januari 2020, lalu dilanjutkan dengan perhitungan debit air hujan dengan metode rasional USSCS, dan perhitungan volume air yang masuk dan tidak masuk ke saluran drainase. Analisis ini berfokus pada ketinggian air banjir akibat curah hujan yang ekstrim, untuk kemudian mendesain sumur resapan. Analisis menggunakan program dilakukan setelah mendapatkan hasil dari perhitungan manual. Hasil analisis ini menyimpulkan bahwa dibutuhkan jutaan sumur resapan untuk menyerap seluruh volume air banjir. Hal ini dikarenakan kondisi muka air tanah yang dangkal dan tingginya curah hujan.

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