scholarly journals Evaluating Impacts of Irrigation and Drought on River, Groundwater and a Terminal Wetland in the Zayanderud Basin, Iran

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1302
Author(s):  
Nizar Abou Zaki ◽  
Ali Torabi Haghighi ◽  
Pekka M. Rossi ◽  
Mohammad J. Tourian ◽  
Alireza Bakhshaee ◽  
...  
Keyword(s):  
Water Mass ◽  
Land Use Changes ◽  
Precipitation Amount ◽  
Standardized Precipitation Index ◽  
Hydrological Drought ◽  
Groundwater Depletion ◽  
Groundwater Exploitation ◽  
In Situ Data ◽  
Surface Water Resources ◽  
Mass Depletion

The Zayanderud Basin is an important agricultural area in central Iran. In the Basin, irrigation consumes more than 90 percent of the water used, which threatens both the downstream historical city of Isfahan and the Gavkhuni Wetland reserve—the final recipient of the river water. To analyze impacts of land use changes and the occurrence of metrological and hydrological drought, we used groundwater data from 30 wells, the standardized precipitation index (SPI) and the streamflow drought index (SDI). Changes in the wetland were analyzed using normalized difference water index (NDWI) values and water mass depletion in the Basin was also assessed with gravity recovery and climate experiment (GRACE)-derived data. The results show that in 45 out of studied 50 years, the climate can be considered as normal in respect to mean precipitation amount, but hydrological droughts exist in more than half of the recorded years. The hydrological drought occurrence increased after the 1970s when large irrigation schemes were introduced. In recent decades, the flow rate reached zero in the downstream part of the Zayanderud River. NDWI values confirmed the severe drying of the Gavkhuni Wetland on several occasions, when compared to in situ data. The water mass depletion rate in the Basin is estimated to be 30 (±5) mm annually; groundwater exploitation has reached an average of 365 Mm3 annually, with a constant annual drop of 1 to 2.5 meters in the groundwater level annually. The results demonstrate the connection between groundwater and surface water resources management and highlight that groundwater depletion and the repeated occurrence of the Zayanderud River hydrological drought are directly related to human activities. The results can be used to assess sustainability of water management in the Basin.

scholarly journals Drought Index as Indicator of Salinization of the Salento Aquifer (Southern Italy)

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1927
Author(s):  
Maria Rosaria Alfio ◽  
Gabriella Balacco ◽  
Alessandro Parisi ◽  
Vincenzo Totaro ◽  
Maria Dolores Fidelibus
Keyword(s):  
Southern Italy ◽  
Karst Aquifer ◽  
Standardized Precipitation Index ◽  
High Water ◽  
Qualitative Assessment ◽  
Groundwater Depletion ◽  
Monthly Precipitation ◽  
Drought Period ◽  
Groundwater Exploitation ◽  
Groundwater Drought

Salento peninsula (Southern Italy) hosts a coastal carbonate and karst aquifer. The semi-arid climate is favourable to human settlement and the development of tourism and agricultural activities, which involve high water demand and groundwater exploitation rates, in turn causing groundwater depletion and salinization. In the last decades these issues worsened because of the increased frequency of droughts, which emerges from the analysis of Standardized Precipitation Index (SPI), calculated during 1949–2011 on the base of monthly precipitation. Groundwater level series and chloride concentrations, collected over the extreme drought period 1989–1990, allow a qualitative assessment of groundwater behaviour, highlighting the concurrent groundwater drought and salinization.

scholarly journals Identifying water mass depletion in northern Iraq observed by GRACE

2015 ◽  
Vol 19 (3) ◽  
pp. 1487-1500 ◽  
Author(s):  
G. Mulder ◽  
T. N. Olsthoorn ◽  
D. A. M. A. Al-Manmi ◽  
E. J. O. Schrama ◽  
E. H. Smidt
Keyword(s):  
Groundwater Depletion ◽  
Model Parameters ◽  
Rainfall Runoff ◽  
Climate Conditions ◽  
Northern Iraq ◽  
In Situ Data ◽  
Grace Data ◽  
Mass Depletion ◽  
Rainfall Runoff Model ◽  
Runoff Model

Abstract. Observations acquired by Gravity Recovery And Climate Experiment (GRACE) mission indicate a mass loss of 146 ± 6 mm equivalent water height (EWH) in northern Iraq between 2007 and 2009. These data are used as an independent validation of lake mass variations and a rainfall-runoff model, which is based on local geology and climate conditions. Model inputs are precipitation from Tropical Rainfall Measurement Mission (TRMM) observations, and climatic parameters from Global Land Data Assimilation Systems (GLDAS) model parameters. The model is calibrated with observed river discharge and includes a representation of the karstified aquifers in the region to improve model realism. Lake mass variations were derived from Moderate Resolution Imaging Spectroradiometer (MODIS) in combination with satellite altimetry and some in situ data. Our rainfall–runoff model confirms that northern Iraq suffered a drought between 2007 and 2009 and captures the annual cycle and longer trend of the observed GRACE data. The total mass depletion seen by GRACE between 2007 and 2009 is mainly explained by a lake mass depletion of 75 ± 3 mm EWH and a natural groundwater depletion of 39 ± 8 mm EWH. Our findings indicate that anthropogenic groundwater extraction has a minor influence in this region, while a decline in lake mass and natural depletion of groundwater play a key role.

scholarly journals The effect of climate type on timescales of drought propagation in an ensemble of global hydrological models

2018 ◽  
Vol 22 (9) ◽  
pp. 4649-4665 ◽  
Author(s):  
Anouk I. Gevaert ◽  
Ted I. E. Veldkamp ◽  
Philip J. Ward
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Spatial Scales ◽  
Standardized Precipitation Index ◽  
Meteorological Drought ◽  
Hydrological Drought ◽  
Propagation Time ◽  
Hydrological Models ◽  
Land Surface Models ◽  
Surface Models

Abstract. Drought is a natural hazard that occurs at many temporal and spatial scales and has severe environmental and socioeconomic impacts across the globe. The impacts of drought change as drought evolves from precipitation deficits to deficits in soil moisture or streamflow. Here, we quantified the time taken for drought to propagate from meteorological drought to soil moisture drought and from meteorological drought to hydrological drought. We did this by cross-correlating the Standardized Precipitation Index (SPI) against standardized indices (SIs) of soil moisture, runoff, and streamflow from an ensemble of global hydrological models (GHMs) forced by a consistent meteorological dataset. Drought propagation is strongly related to climate types, occurring at sub-seasonal timescales in tropical climates and at up to multi-annual timescales in continental and arid climates. Winter droughts are usually related to longer SPI accumulation periods than summer droughts, especially in continental and tropical savanna climates. The difference between the seasons is likely due to winter snow cover in the former and distinct wet and dry seasons in the latter. Model structure appears to play an important role in model variability, as drought propagation to soil moisture drought is slower in land surface models (LSMs) than in global hydrological models, but propagation to hydrological drought is faster in land surface models than in global hydrological models. The propagation time from SPI to hydrological drought in the models was evaluated against observed data at 127 in situ streamflow stations. On average, errors between observed and modeled drought propagation timescales are small and the model ensemble mean is preferred over the use of a single model. Nevertheless, there is ample opportunity for improvement as substantial differences in drought propagation are found at 10 % of the study sites. A better understanding and representation of drought propagation in models may help improve seasonal drought forecasting as well as constrain drought variability under future climate scenarios.

scholarly journals CARACTERÍSTICAS OCEANOGRÁFICAS EN LA ISLA MALPELO Y SU RELACIÓN CON LA CUENCA OCEÁNICA DEL PACÍFICO COLOMBIANO

2016 ◽  
Vol 40 ◽  
Author(s):  
Efraín Rodríguez Rubio ◽  
Alan Giraldo
Keyword(s):  
Water Mass ◽  
Terrestrial Ecosystems ◽  
In Situ Data ◽  
Pelagic Environment ◽  
Shallow Subtidal ◽  
Oceanographic Data ◽  
Malpelo Island ◽  
Physical And Chemical ◽  
Colombian Pacific

Malpelo Island forms the insular ecoregion of the Colombian Pacific, and is composed by a mosaic of terrestrial ecosystems, and unique coastal and shallow subtidal systems. Considering its insular nature, the oceanographic features of this locality are expected to be related with the physical and chemical dynamics of the Eastern Tropical Pacific (ETP) and be modulated by the regional dynamic of the Colombian Pacific Oceanic Basin (COPC in Spanish). In this work, in situ data was used to describe the thermohaline conditions in the water column in Malpelo Island and identify key water mass during the two contrasting hydro-meteorological periods of the COPC. Furthermore, we analyzed the thermal and haline variability in the COPC and defined the surface geostrophic flow from in situ oceanographic data during the same time in order to evaluate its effect on the oceanographic conditions in the pelagic environment off Malpelo Island.

scholarly journals Space-time variability of hydrological drought and wetness in Iran using NCEP/NCAR and GPCC datasets

2010 ◽  
Vol 14 (10) ◽  
pp. 1919-1930 ◽  
Author(s):  
T. Raziei ◽  
I. Bordi ◽  
L. S. Pereira ◽  
A. Sutera
Keyword(s):  
Time Series ◽  
Singular Spectrum Analysis ◽  
Standardized Precipitation Index ◽  
Principal Component ◽  
Reanalysis Data ◽  
Space Time ◽  
Hydrological Drought ◽  
Time Variability ◽  
Climate Conditions ◽  
Good Agreement

Abstract. Space-time variability of hydrological drought and wetness over Iran is investigated using the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis and the Global Precipitation Climatology Centre (GPCC) dataset for the common period 1948–2007. The aim is to complement previous studies on the detection of long-term trends in drought/wetness time series and on the applicability of reanalysis data for drought monitoring in Iran. Climate conditions of the area are assessed through the Standardized Precipitation Index (SPI) on 24-month time scale, while Principal Component Analysis (PCA) and Varimax rotation are used for investigating drought/wetness variability, and drought regionalization, respectively. Singular Spectrum Analysis (SSA) is applied to the time series of interest to extract the leading nonlinear components and compare them with linear fittings. Differences in drought and wetness area coverage resulting from the two datasets are discussed also in relation to the change occurred in recent years. NCEP/NCAR and GPCC are in good agreement in identifying four sub-regions as principal spatial modes of drought variability. However, the climate variability in each area is not univocally represented by the two datasets: a good agreement is found for south-eastern and north-western regions, while noticeable discrepancies occur for central and Caspian sea regions. A comparison with NCEP Reanalysis II for the period 1979–2007, seems to exclude that the discrepancies are merely due to the introduction of satellite data into the reanalysis assimilation scheme.

Quantifying the mechanical response of the Izaña area (Tenerife) to sustained groundwater withdrawal 

2021 ◽  
Author(s):  
Anthony Lamur ◽  
Silvio De Angelis ◽  
Rayco Marrero ◽  
Yan Lavallée ◽  
Pablo J. Gonzalez
Keyword(s):  
Mechanical Response ◽  
Water Saturation ◽  
Poisson Ratio ◽  
Porous Network ◽  
P Waves ◽  
Groundwater Exploitation ◽  
Horizontal Drilling ◽  
Surface Water Resources ◽  
Aquifer Systems ◽  
Wide Range

<p>Surface water resources on volcanic islands with moderate rainfall and relatively high permeability are usually scarce or non-existent. As such, life and local economies of these islands mostly relies on groundwater exploitation. It is therefore important to characterise the sustainability of volcanic aquifer systems. In short, an aquifer is deemed in equilibrium when the recharge rate equals or exceeds the exploitation rate. The Izaña area in Tenerife Island (Canary Islands, Spain) has been exploited since the 1900s via a series of ~30 horizontal drilling or water galleries coming from both flanks of the NE-Ridge. Since exploitation began, the water table has dropped continuously, in some area even more than 200 m. Since the 2000s, aquifer dynamics (compaction) have been observed using InSAR indicating a subsidence rate of up to 2 cm per year.</p><p>Here, we investigate a suite of rock samples collected. The samples were collected at several water galleries aiming to be representative of the aquifer materials from the Izaña area. We first characterise the basic physical properties of each samples (porosity, permeability, solid density) before quantifying the elastic parameters (Young’s modulus, Poisson ratio) and uniaxial strength of the lithologies collected. We also measure V<sub>p</sub> under dry and wet conditions (i.e. different saturation levels) to assess whether water saturation can alter the velocity of P-waves passing through those rocks.</p><p>Preliminary results show that connected porosities range from 0.16 to 45%, conferring a wide range of mechanical response to increasing effective pressure, with strength ranging from 18 – 315 MPa and Young’s moduli ranging from 3 – 57 GPa. In a similar fashion, results for V<sub>p</sub> measurements also exhibit a range of values (~1.5 – 4.5 km/s). These data show that materials present in the aquifer are extremely varied, suggesting that both fluid flow and observed deformation are likely to be controlled by the weakest, most porous lithologies.</p><p>These results will further be integrated with the lithostratigraphic record of the aquifer in order to model the mechanical response of the aquifer to changes in effective pressures, and specifically pore pressure reduction with water extraction. Additionally, chemical and textural analysis will provide insights on the evolution of the porous network at different alteration levels, here serving as a proxy for time at saturation in the aquifer. Finally, we aim to compare the experimental results from laboratory measurements to those of hydro-geophysical measurements that will be collected in the field starting in mid-2021.</p>

scholarly journals Changes in Net Global Surface Water Area Since 1985

Proceedings ◽  
2020 ◽  
Vol 30 (1) ◽  
pp. 69
Author(s):  
Zahra Kalantari ◽  
Sonia Borja ◽  
Georgia Destouni
Keyword(s):  
Surface Water ◽  
Ecosystem Functioning ◽  
Water Allocation ◽  
Land Use Changes ◽  
Water Area ◽  
Aral Sea ◽  
Surface Water Resources ◽  
Global Surface ◽  
Spatial And Temporal Characteristics

Spatial and temporal characteristics of surface water resources (e.g., extension, connectivity, seasonality) are key elements in water allocation, climate and hydrological regulation, ecosystem functioning, and the food-energy-water nexus. Changes in surface water area due to losses/gains to land could strongly affect these processes on different scales. Previous findings on changes in the Earth’s surface water area are contradictory. Based on water–land year classification datasets, we estimated global surface water area changes between 1985–2000 and 2001–2015. We found a net global gain in surface water of 100,454 km2, attributable to a large net gain in seasonal water (83,329 km2) and a small net gain in permanent water (17,125 km2). In general, net changes were highly heterogeneous in space, with local exceptions of clear drying and wetting trends, e.g., the Aral Sea and Quill Lakes, respectively. These findings raise multiple questions as to why seasonal water gains dominate and how different intertwined drivers (e.g., hydroclimate and human-induced water–land use changes) shape the distribution of the Earth’s surface water. Understanding these long-term changes is essential to predicting water-related pressures and prioritizing management decisions.

scholarly journals Climate Change Impact on the Frequency of Hydrometeorological Extremes in the Island of Crete

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 587 ◽  
Author(s):  
Evdokia Tapoglou ◽  
Anthi Vozinaki ◽  
Ioannis Tsanis
Keyword(s):  
Climate Change ◽  
Frequency Analysis ◽  
Extreme Precipitation ◽  
Climate Model ◽  
Regional Climate ◽  
Standardized Precipitation Index ◽  
Hydrological Drought ◽  
Drought Indices ◽  
Rcp Scenarios ◽  
The Impact

Frequency analysis on extreme hydrological and meteorological events under the effect of climate change is performed in the island of Crete. Data from Regional Climate Model simulations (RCMs) that follow three Representative Concentration Pathways (RCP2.6, RCP4.5, RCP8.5) are used in the analysis. The analysis was performed for the 1985–2100 time period, divided into three equal-duration time slices (1985–2010, 2025–2050, and 2075–2100). Comparison between the results from the three time slices for the different RCMs under different RCP scenarios indicate that drought events are expected to increase in the future. The meteorological and hydrological drought indices, relative Standardized Precipitation Index (SPI) and Standardized Runoff index (SRI), are used to identify the number of drought events for each RCM. Results from extreme precipitation, extreme flow, meteorological and hydrological drought frequency analysis over Crete show that the impact of climate change on the magnitude of 100 years return period extreme events will also increase, along with the magnitude of extreme precipitation and flow events.

Changes in hydrological behaviour: case studies of the Unica and Rižana karst springs, Slovenia

2020 ◽  
Author(s):  
Natasa Ravbar ◽  
Gregor Kovačič ◽  
Metka Petrič
Keyword(s):  
Land Use ◽  
Large Scale ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
Land Use Changes ◽  
Precipitation Amount ◽  
Flood Pulse ◽  
Karst Springs ◽  
The Impact ◽  
Gauging Station

<p>Environmental changes, such as alterations in precipitation and evapotranspiration regimes, changes in vegetation type, etc. are triggering direct impact on hydrological cycle through modified amounts and patterns of recharge conditions, as well as occurrence of more frequent and severe hydrometeorological events. Karst aquifers are particularly vulnerable to these effects due to highly dynamic hydrological processes. In this study, we were interested in studying the possibilities to observe changed hydrological behaviour of karst springs on a human timescale. Therefore, we focused on two examples in Slovenia, both regionally important for freshwater supply, agriculture and hydropower. The Unica spring mostly drains areas under moderate continental climate. Its catchment has been repeatedly and severely hit by natural disasters (e.g., ice break, bark beetle attack, windthrow) after 2014 causing large-scale forest disturbances. The catchment of Rižana spring, on the other hand, belongs to the moderate Submediterranean climate. There these types of disturbance did not occur in recent years (excluding some wildfires), but the catchment has been liable to substantial land use changes in the past six decades. For assessment of vegetation cover changes and large-scale disturbances in forests, historical digital orthophotos of the Surveying and Mapping Authority of the Republic of Slovenia since 1957 have been compared with the recent land use data provided by Ministry of Agriculture, Economy and Food and forest state database of Slovenian Forest Service. At the same time, hydrological data of the Unica (Hasberg gauging station) in the period 1962-2018 and Rižana springs (Kubed gauging station) in the period 1966-2018 and precipitation data from Postojna (period 1962-2018) and Podgrad (period 1966-2018) meteorological stations have been processed. Individual flood pulse events over the 57 years for Unica and 53 years for Rižana have been separated. For each flood pulse various information about precipitation amount and intensity, duration of discharge increase, its intensity and amplitude have been specified. We compared these findings with the calculated trends of meteorological and hydrological variables and also changes in land use. The impact of particular environmental change on discharge values of both springs has been evaluated, showing that both, climate and land-use changes, have considerable impact on hydrological regime of studied karst springs. In particular, altered duration of flood pulses increase, their amplitude and intensity have been observed, meaning that the most important issues of water availability that are crucial for water-dependant economic sectors are under threat.</p>

scholarly journals Water-Mass Transformations in a Neutral Density Framework and the Key Role of Light Penetration

2008 ◽  
Vol 38 (7) ◽  
pp. 1357-1376 ◽  
Author(s):  
Daniele Iudicone ◽  
Gurvan Madec ◽  
Trevor J. McDougall
Keyword(s):  
Water Mass ◽  
Numerical Models ◽  
Potential Temperature ◽  
Shortwave Radiation ◽  
Neutral Density ◽  
In Situ Data ◽  
Water Mass Formation ◽  
New Formulation ◽  
Surface Buoyancy ◽  
Mass Formation

Abstract A new formulation is proposed for the evaluation of the dianeutral transport in the ocean. The method represents an extension of the classical diagnostic approach for estimating the water-mass formation from the buoyancy balance. The inclusion of internal sources such as the penetrative solar shortwave radiation (i.e., depth-dependent heat transfer) in the estimate of surface buoyancy fluxes has a significant impact in several oceanic regions, and the former simplified formulation can lead to a 100% error in the estimate of water-mass formation due to surface buoyancy fluxes. Furthermore, internal mixing can also be overestimated in inversions of in situ data when the shortwave radiation is not allowed to be penetrative. The method examines the evolution equation of neutral density via the tendencies of potential temperature and salinity. The neutral density framework does not require the choice of a reference pressure and thus, unlike previous approaches that consider potential density, it is well suited for examining the whole open-ocean water column. The methodology is easy to implement, particularly for ocean numerical models. The authors present here its application to a long simulation made with an ice–ocean global model, which allowed the method to be validated.

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