scholarly journals GROUNDWATER CONCEPTUAL MODEL FOR PADDY IRRIGATION

2015 ◽  
Vol 78 (1-2) ◽  
Author(s):  
Ahmad Fikri Abdullah ◽  
Wan Amirul Wan Mustapa
Keyword(s):  
Groundwater Flow ◽  
Conceptual Model ◽  
Root Zone ◽  
Groundwater Resources ◽  
Visual Modflow ◽  
Alternative Source ◽  
Aquifer Storage ◽  
Paddy Irrigation ◽  
Rice Irrigation ◽  
Current Water

Hydrological modelling is representative of current, past or future hydrologic balance. It has been used widely in water-related problem such as drought, flood, water contamination and irrigation. Crops irrigation requires a lot of water to irrigate the root zone layer especially for paddy crops. With the current issues of water such as drought and pollution, an alternative source is needed to overcome the problem of water scarcity.  Generally Malaysia depends on the surface water to irrigate the crops with no aided of groundwater. This study focuses on the availability of groundwater resources to irrigate the paddy crops. Hence, a conceptual model of groundwater flow was developed to shows the current situation of the groundwater flow at the study area. Several models were developed to see if groundwater can be extracted using wells and be used as an alternative source for irrigation. The study area is located at Sawah Sempadan, which is one of Malaysia’s greeneries areas under Tanjung Karang Rice Irrigation Scheme (TAKRIS). The conceptual model is built by using Visual MODFLOW 4.2. The conceptual model shows the current water balance, water table elevation and equipotential head in the study area. Simulations with pump wells have been done to shows the availability of groundwater sources for paddy irrigation. The result shows that groundwater flows from area of higher elevation towards the lower elevated area. It is also shows that groundwater extraction could not be too excessive as it may dry up the aquifer storage.

Application of Visual MODFLOW to the Analysis of Boundary Conditions for a Phreatic Porous Aquifer Using Limited Available Information: A Case Study

2021 ◽  
Vol 44 ◽  
Author(s):  
Milena Stefany Lage Almeida ◽  
JOSÉ AUGUSTO COSTA GONÇALVES
Keyword(s):  
Boundary Conditions ◽  
Groundwater Flow ◽  
Root Mean Square ◽  
Flow Behavior ◽  
Groundwater Resources ◽  
Absolute Error ◽  
Mean Square ◽  
Visual Modflow ◽  
Porous Aquifer ◽  
The Mean

The increasing water demand, especially in developing regions, continuously puts pressure on groundwater resources both quantitatively and qualitatively. Hydrogeological modeling is a tool used in planning and management of groundwater resources. The factors that interfere in groundwater flow dynamics can be determined by developing a conceptual model and they can be validated via a numerical model. The objective of the manuscript is the hydrogeological groundwater flow modeling of the phreatic porous aquifer of the Ribeirão Candidópolis catchment in the Itabira municipality, State of Minas Gerais (Brazil). The software used in this study is GMS: MODFLOW, which enabled a steady state flow regime modeling by means of the Finite Difference Method (FDM) and the parameters calibration from a semi-transient approach. To assess the performance of the model, the Mean Error (ME), the Mean Absolute Error (MAE), and the Root Mean Square Error (RMSE) were calculated. The results proved to be compatible with the values observed in the field. After several adjustments of the boundary conditions, a Normalized Root Mean Square (NRMS) of 9.648% and a correlation coefficient of 0.993 were obtained. Despite the economic importance of the study area, studies made available on groundwater flow behavior are rare. The results obtained via modeling are in accordance with the data observed in the field and consequently our model can be used in the study of water level changes.

scholarly journals Solutions for groundwater flow with sloping stream boundary: analytical, numerical and experimental models

2017 ◽  
Vol 49 (4) ◽  
pp. 1120-1130 ◽  
Author(s):  
Uğur Boyraz ◽  
Cevza Melek Kazezyılmaz-Alhan
Keyword(s):  
Surface Water ◽  
Groundwater Flow ◽  
Laboratory Experiments ◽  
Groundwater Resources ◽  
Experimental Models ◽  
Flow Equation ◽  
Visual Modflow ◽  
Aquifer System ◽  
Aquifer Characteristics ◽  
Made In

Abstract Protecting groundwater resources plays an important role in watershed management. For this purpose, studies on groundwater flow dynamics incorporating surface water–groundwater interactions have been conducted including analytical, numerical, and experimental models. In this research, a stream–aquifer system was considered to understand the physical behavior of surface water–groundwater interactions. Interactions in a stream–aquifer system were incorporated into the mathematical modeling by defining the stream head as a boundary condition for the groundwater flow equation. This boundary was chosen as a sloping stream boundary, which is an approach in representing the natural conditions of the stream and may be used to define continuous interactions between stream and aquifer. A semi-analytical solution for transient 2D groundwater flow was developed for the considered problem. Isotropic, homogeneous, and finite aquifer assumptions were made in order to define the aquifer characteristics. Then, a series of laboratory experiments was conducted to simulate this stream–aquifer system. Finally, a numerical model was developed by using Visual MODFLOW to verify analytical and experimental results. Numerical results matched with both analytical solutions and the experimental observations.

scholarly journals Numerical modeling of the groundwater flow in the fractured and karst aquifer of the Salento peninsula (Southern Italy)

2013 ◽  
Author(s):  
Giovanna De Filippis ◽  
Mauro Giudici ◽  
Stefano Margiotta ◽  
Fiorella Mazzone ◽  
Sergio Negrini ◽  
...  
Keyword(s):  
Water Balance ◽  
Groundwater Flow ◽  
Conceptual Model ◽  
Southern Italy ◽  
Climatic Factors ◽  
Groundwater Resources ◽  
Regional Scale ◽  
Karst Aquifer ◽  
Aquifer System ◽  
Complex Relationships

Water resources represented by coastal aquifers are very important for regions characterized by a relevant request of freshwater, but limited rainfall, lack of surface water bodies and intrusion of the seawater through the sediments which host groundwater. Therefore some coastal areas, like the Salento peninsula (southern Italy), are subjected to the risk of desertification and a proper management of groundwater resources requires tools to analyze and predict the water balance and the evolution of the physical system in response to human activities (e.g., ground water withdrawals) and climatic factors. The Salento peninsula is a typical Mediterranean basin, where the main water resource is the aquifer hosted in Cretaceous carbonatic rocks (Calcare di Altamura, Altamura limestone): this is a fractured and karst aquifer, with a poor recharge and complex relationships with the sea. In order to develop a tool to assess the water balance at regional scale for the considered aquifer system, a groundwater flow model was developed by Giudici et al. (2012a); it is based on a conceptual model obtained from a reconstruction of the hydrostratigraphic architecture of the region, which includes the main aquifer and the overlaying rocks characterized by low permeability which can host local and relatively thin aquifers. In this paper that work is updated, by improving the reconstruction of the hydraulic head and of the conceptual model, above all in those areas that the previous model evidenced as critical for the absence of fresh water along the whole aquifer thickness. Moreover, since the estimate of some model’s input parameters is affected by high uncertainty, a sensitivity analysis is performed to evaluate the effects of this uncertainty on the model’s results.

scholarly journals Hydrogeological Conceptual Model in the Middle of Randublatung Groundwater Basin

2021 ◽  
Vol 926 (1) ◽  
pp. 012078
Author(s):  
D L Setyaningsih ◽  
K D Setyawan ◽  
D P E Putra ◽  
Salahuddin
Keyword(s):  
Groundwater Flow ◽  
Conceptual Model ◽  
Unconfined Aquifer ◽  
Primary Data ◽  
Essential Information ◽  
Aquifer System ◽  
The North ◽  
Shallow Wells ◽  
Groundwater Basin ◽  
Constant Head

Abstract Randublatung groundwater basin is one of the groundwaters basins with massive utilization of groundwater pumping. However, the knowledge of the comprehensive hydrogeological system in this groundwater basin is limited, so this research aims to determine a comprehensive hydrogeological conceptual model of the Randublatung groundwater basin. The methodology was conducted by collecting secondary and primary data of deep and shallow wells to evaluate boundaries of pattern and direction of groundwater flow and develop the aquifer system’s geometry. The result shows that the groundwater flow boundaries are Grogol River in the west, Wado River in the East, Bengawan Solo river in the South as a river boundary, and Rembang Mountains in the North as a constant head boundary. Therefore, groundwater flows from the hills area to the Bengawan Solo River and the north as the river’s flow. Based on the log bor evaluation, the aquifer system of the study area consist of an unconfined aquifer with a maximum thickness of 20 m and three layers of confined aquifers with thickness vary between 8 to 60 m. the hydraulic conductivity of the aquifers depends on the aquifer’s lithology range from sand, gravel, limestone, and sandstone. This hydrogeological conceptual model provides essential information for numerical groundwater models in the middle of the Randublatung groundwater basin.

scholarly journals Proposing the Optimum Withdrawing Scenarios to Provide the Western Coastal Area of Port Said, Egypt, with Sufficient Groundwater with Less Salinity

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3359
Author(s):  
Mohamed Abdelfattah ◽  
Heba Abdel-Aziz Abu-Bakr ◽  
Ahmed Gaber ◽  
Mohamed H. Geriesh ◽  
Ashraf Y. Elnaggar ◽  
...  
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Sustainable Management ◽  
Groundwater Resources ◽  
Field Investigation ◽  
Visual Modflow ◽  
Groundwater Abstraction ◽  
Human Needs ◽  
Western Area ◽  
Port Said

Recently, groundwater resources in Egypt have become one of the important sources to meet human needs and activities, especially in coastal areas such as the western area of Port Said, where seawater desalination cannot be used due to the problem of oil spill and the reliance upon groundwater resources. Thus, the purpose of the study is the sustainable management of the groundwater resources in the coastal aquifer entailing groundwater abstraction. In this regard, the Visual MODFLOW and SEAWAT codes were used to simulate groundwater flow and seawater intrusion in the study area for 50 years (from 2018 to 2068) to predict the drawdown, as well as the salinity distribution due to the pumping of the wells on the groundwater coastal aquifer based on field investigation data and numerical modelling. Different well scenarios were used, such as the change in well abstraction rate, the different numbers of abstraction wells, the spacing between the abstraction wells and the change in screen depth in abstraction. The recommended scenarios were selected after comparing the predicted drawdown and salinity results for each scenario to minimize the seawater intrusion and preserve these resources from degradation.

3D modelling of a hydrological structure combining spatial data science and geophysics: Application to a coastal aquifer system in the island of Crete, Greece

2021 ◽  
Author(s):  
Emmanouil Varouchakis ◽  
Leonardo Azevedo ◽  
João L. Pereira ◽  
Ioannis Trichakis ◽  
George P. Karatzas ◽  
...  
Keyword(s):  
Climate Change ◽  
Groundwater Flow ◽  
Spatial Data ◽  
Coastal Aquifer ◽  
Data Science ◽  
Flow Model ◽  
Groundwater Resources ◽  
Geostatistical Simulation ◽  
Groundwater Flow Model ◽  
Aquifer System

<p>Groundwater resources in Mediterranean coastal aquifers are under threat due to overexploitation and climate change impacts, resulting in saltwater intrusion. This situation is deteriorated by the absence of sustainable groundwater resources management plans. Efficient management and monitoring of groundwater systems requires interpreting all sources of available data. This work aims at the development of a set of plausible 3D geological models combining 2D geophysical profiles, spatial data analytics and geostatistical simulation techniques. The resulting set of models represents possible scenarios of the structure of the coastal aquifer system under investigation. Inverted resistivity profiles, along with borehole data, are explored using spatial data science techniques to identify regions associated with higher uncertainty. Relevant parts of the profiles will be used to generate 3D models after detailed Anisotropy and variogram analysis. Multidimensional statistical techniques are then used to select representative models of the true subsurface while exploring the uncertainty space. The resulting models will help to identify primary gaps in existing knowledge about the groundwater system and to optimize the groundwater monitoring network. A comparison with a numerical groundwater flow model will identify similarities and differences and it will be used to develop a typical hydrogeological model, which will aid the management and monitoring of the area's groundwater resources. This work will help the development of a reliable groundwater flow model to investigate future groundwater level fluctuations at the study area under climate change scenarios.</p><p> </p><p>This work was developed under the scope of the InTheMED project. InTheMED is part of the PRIMA programme supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 1923.</p>

A GIS-based assessment of spatial groundwater quality for drinking purposes in Asmara City, Eritrea

2021 ◽  
Author(s):  
Kabral Mogos Asghede ◽  
Dawit Berhane Hagos
Keyword(s):  
Groundwater Quality ◽  
Potable Water ◽  
Critical Level ◽  
Groundwater Resources ◽  
Total Dissolved Solids ◽  
Total Hardness ◽  
Analysis Framework ◽  
Alternative Source ◽  
Drinking Purposes ◽  
Supply Problem

<p><strong>Abstract</strong>: Presently the water-supply problem in the Asmara area has reached to a critical level. Using a GIS-based method this study identifies the spatial variability of the groundwater quality in the Asmara Area which could be an alternative source. The results show that, the Total Dissolved Solids (TDS), Total Hardness (TH), Chloride (Cl<sup>-</sup>), Nitrates (NO<sub>3</sub><sup>-</sup>), Calcium (Ca), Magnesium (Mg), Sulphate (SO<sub>4</sub>) and pH are 791.71, 569.12, 124.41, 64.46, 155.60, 46.64, 159.26 and 7.72 mg/L, respectively. Moreover, the zone map of the developed groundwater quality shows that the potable water without treatment covers about 35%, and the potable water in the absence of better alternate sources covers about 58% of the total area. The remaining, 7.04% of the total, falls under non-potable groundwater quality. The verification of the spatialanalysis demonstrates that the framework is the first one in Eritrea and could be used as a potential prediction for the assessment of the spatial groundwater quality in the countries with further verification results. Hence, the delineation of groundwater quality zones and establishment of a GIS-based database will easily help the decision makersto monitor and plan the utilization of the groundwater resources in the study area.</p><p><strong>Keywords: </strong>Groundwater quality; physicochemical parameters; GIS spatial analysis; framework</p>

Spatial variability and changes in storage-discharge relationships of crystalline catchments: implications for resilience and water resources management

2021 ◽  
Author(s):  
Ronan Abhervé ◽  
Clément Roques ◽  
Laurent Longuevergne ◽  
Stéphane Louaisil ◽  
Jean-Raynald de Dreuzy ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Water Cycle ◽  
Groundwater Resources ◽  
Time Lag ◽  
Management Strategies ◽  
Reservoir Storage ◽  
Aquifer Storage ◽  
Water Resources Availability ◽  
Societal Needs

<p>While it is well understood and accepted that climate change and growing water needs affect the availability of water resources, the identification of the main physical processes involved remains challenging. It notably requires to filter interannual to interdecadal fluctuations and extreme events to isolate the underlying trends. Metropolitan areas are specifically subject to growing pressures because of the significant and increasing demand, combined with the strong anthropization of land uses.</p><p>The Meu-Chèze-Canut catchment supplies the city of Rennes with drinking water (680 km² - 500 000 users, Brittany, France). In this field laboratory, we explore the dynamics of the water cycle and water resources availability. In this context, water supply is mostly coming from reservoir storage for which levels shows a medium-term vulnerability in response to frequent relatively dry years. Based on retrospective data analysis, we describe the relationship between climatic forcing (precipitation, temperature) and water availability (aquifer storage, river discharge and reservoir storage) in different parts of the catchment that are characterized by distinct lithological and topographical settings. We then evaluate the resilience of both surface and groundwater resources, their past evolution and their resilience to climate change and increasing societal needs.</p><p>Water resources availability in these catchments relies on two geological formations with distinct hydrodynamics properties: the Armorican sandstone and Brioverian schist. To assess the resilience of the system, we specifically analyzed the relationships between monthly effective precipitation and stream discharge within nine sub-catchments over the past 30 years. We observe annual hysteresis relationships - that is, a time lag between precipitation and discharge highlighting the capacity of the landscape to temporarily store water - with significant variability in shapes across the catchments. We argue that topographic and lithological factors play key roles in controlling this variability through their impacts on subsurface storage capacity and characteristic drainage timescales. We propose perspectives based on the complementary use of calibrated groundwater models to leverage these results and provide adaptive water management strategies.</p>

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