Detailed hydrogeological studies are often necessary to assess the water balance of a watershed. Understanding the hydrogeological structures makes it possible to establish the watershed boundaries, to verify the congruence of the watershed hydrographic boundaries and the boundaries of the groundwater basin (Chapter 2), to locate the aquifers at various depths, and to establish the relationship between these aquifers and the surface water. In reminder, the groundwater system is connected to the hydrological cycle by various processes: infiltration through the unsaturated zone, contribution to ground-water by percolation and leakage, evaporation from the unsaturated zone, and finally, groundwater outflow. Definitions: Aquifers and Types of Groundwater Hydrogeology is based on the analysis of two essential entities: the aquifer and the groundwater table: An is a permeable geological formation (soil or rock) with pores or cracks that interconnect and that are sufficiently large that water can freely circulate under the effect of gravity (examples: sands, gravels, fissured chalk, sandstone, etc). In this way, the aquifer constitutes a reservoir for the groundwater tables. The is all the water contained in the saturated zone of the

Hydrology ◽  
2010 ◽  
pp. 227-228
2013 ◽  
Vol 21 (3) ◽  
pp. 43-56
Author(s):  
Beáta Hamar Zsideková ◽  
Balázs Gauzer ◽  
Gábor Bálint

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.


2020 ◽  
Author(s):  
Jui-Hsiang Lo ◽  
Hung-Yen Lin ◽  
Yung-Chia Chiu ◽  
Tsung-Yu Lee ◽  
Yi-Zhih Tsai ◽  
...  

<p>Studies have indicated that the streambed with the clogging layer affects the interaction between surface water and groundwater. When the streambed covered by a clogging layer, the decrease of the groundwater table can transform the state of stream-groundwater from the connection into disconnection. When the stream-groundwater interaction reaches the state of disconnection, the infiltration rate is independent with the groundwater level beneath the streambed. In this study, we show the effects of the topography of the streambed and clogging layer on the infiltration and groundwater flow patterns beneath the streambed by numerical simulations. The results show that the clogging layer and the change of topography of streambed affect the development of the unsaturated zone, flow path, and residence time beneath the streambed.</p>


2014 ◽  
Vol 12 (2) ◽  
pp. 165-182 ◽  
Author(s):  
Tertia Barnett ◽  
Maria Guagnin

This article examines the relationship between rock art and landscape use by pastoral groups and early settled communities in the central Sahara from around 6000 BC to 1000 AD. During this period the region experienced significant climatic and environmental fluctuations. Using new results from a systematic survey in the Wadi al-Ajal, south-west Libya, our research combines data from over 2000 engraved rock art panels with local archaeological and palaeoenvironmental evidence within a GIS model. Spatial analysis of these data indicates a correspondence between the frequency of rock art sites and human settlement over time. However, while changes in settlement location were guided primarily by the constraints on accessibility imposed by surface water, the distribution of rock art relates to the availability of pasture and patterns of movement through the landscape. Although the reasons for these movements undoubtedly altered over time, natural routes that connected the Wadi al-Ajal and areas to the south continued to be a focus for carvings over several thousand years.


2018 ◽  
Vol 54 (3) ◽  
pp. 2436-2451 ◽  
Author(s):  
Pei Xin ◽  
Shen S. J. Wang ◽  
Chengji Shen ◽  
Zeyu Zhang ◽  
Chunhui Lu ◽  
...  

2011 ◽  
Vol 71 (1 suppl 1) ◽  
pp. 241-253 ◽  
Author(s):  
HC Gonçalves ◽  
MA Mercante ◽  
ET Santos

The Pantanal hydrological cycle holds an important meaning in the Alto Paraguay Basin, comprising two areas with considerably diverse conditions regarding natural and water resources: the Plateau and the Plains. From the perspective of the ecosystem function, the hydrological flow in the relationship between plateau and plains is important for the creation of reproductive and feeding niches for the regional biodiversity. In general, river declivity in the plateau is 0.6 m/km while declivity on the plains varies from 0.1 to 0.3 m/km. The environment in the plains is characteristically seasonal and is home to an exuberant and abundant diversity of species, including some animals threatened with extinction. When the flat surface meets the plains there is a diminished water flow on the riverbeds and, during the rainy season the rivers overflow their banks, flooding the lowlands. Average annual precipitation in the Basin is 1,396 mm, ranging from 800 mm to 1,600 mm, and the heaviest rainfall occurs in the plateau region. The low drainage capacity of the rivers and lakes that shape the Pantanal, coupled with the climate in the region, produce very high evaporation: approximately 60% of all the waters coming from the plateau are lost through evaporation. The Alto Paraguay Basin, including the Pantanal, while boasting an abundant availability of water resources, also has some spots with water scarcity in some sub-basins, at different times of the year. Climate conditions alone are not enough to explain the differences observed in the Paraguay River regime and some of its tributaries. The complexity of the hydrologic regime of the Paraguay River is due to the low declivity of the lands that comprise the Mato Grosso plains and plateau (50 to 30 cm/km from east to west and 3 to 1.5 cm/km from north to south) as well as the area's dimension, which remains periodically flooded with a large volume of water.


2012 ◽  
Vol 16 (3) ◽  
pp. 649-669 ◽  
Author(s):  
G. H. de Rooij

Abstract. The increasing importance of catchment-scale and basin-scale models of the hydrological cycle makes it desirable to have a simple, yet physically realistic model for lateral subsurface water flow. As a first building block towards such a model, analytical solutions are presented for horizontal groundwater flow to surface waters held at prescribed water levels for aquifers with parallel and radial flow. The solutions are valid for a wide array of initial and boundary conditions and additions or withdrawals of water, and can handle discharge into as well as lateral infiltration from the surface water. Expressions for the average hydraulic head, the flux to or from the surface water, and the aquifer-scale hydraulic conductivity are developed to provide output at the scale of the modelled system rather than just point-scale values. The upscaled conductivity is time-variant. It does not depend on the magnitude of the flux but is determined by medium properties as well as the external forcings that drive the flow. For the systems studied, with lateral travel distances not exceeding 10 m, the circular aquifers respond very differently from the infinite-strip aquifers. The modelled fluxes are sensitive to the magnitude of the storage coefficient. For phreatic aquifers a value of 0.2 is argued to be representative, but considerable variations are likely. The effect of varying distributions over the day of recharge damps out rapidly; a soil water model that can provide accurate daily totals is preferable over a less accurate model hat correctly estimates the timing of recharge peaks.


Wetlands ◽  
2017 ◽  
Vol 37 (6) ◽  
pp. 1055-1065 ◽  
Author(s):  
L. J. Heintzman ◽  
S. M. Starr ◽  
K. R. Mulligan ◽  
L. S. Barbato ◽  
N. E. McIntyre

2014 ◽  
Vol 11 (2) ◽  
pp. 2011-2044
Author(s):  
R. Barthel

Abstract. Today there is a great consensus that water resources research needs to become more holistic, integrating perspectives of a large variety of disciplines. Groundwater and surface water (hereafter: GW and SW) are typically identified as different compartments of the hydrological cycle and were traditionally often studied and managed separately. However, despite this separation, these respective fields of study are usually not considered to be different disciplines. They are often seen as different specialisations of hydrology with different focus, yet similar theory, concepts, methodology. The present article discusses how this notion may form a substantial obstacle in the further integration of GW and SW research and management. The article focusses on the regional scale (areas of approx. 103 to 106 km2), which is identified as the scale where integration is most greatly needed, but ironically the least amount of fully integrated research seems to be undertaken. The state of research on integrating GW and SW research is briefly reviewed and the most essential differences between GW hydrology (or hydrogeology, geohydrology) and SW hydrology are presented. Groundwater recharge and baseflow are used as examples to illustrate different perspectives on similar phenomena that can cause severe misunderstandings and errors in the conceptualisation of integration schemes. It is also discussed that integration of GW and SW research on the regional scale necessarily must move beyond the hydrological aspects, by collaborating with social sciences and increasing the interaction between science and the society in general. The typical elements of an ideal interdisciplinary workflow are presented and their relevance with respect to integration of GW and SW is discussed. The overall conclusions are that GW hydrology and SW hydrogeology study rather different objects of interest, using different types of observation, working on different problem settings. They have thus developed different theory, methodology and terminology. Yet, there seems to be a widespread lack of awareness of these differences which hinders the detection of the existing interdisciplinary aspects of GW and SW integration and consequently the development of truly unifying, interdisciplinary theory and methodology. Thus, despite having the ultimate goal of creating a more holistic approach, we should start integration by analysing potential disciplinary differences. Improved understanding among hydrologists of what interdisciplinary means and how it works is needed. Hydrologists, despite frequently being involved in multidisciplinary projects, are not sufficiently involved in developing interdisciplinary strategies and do usually not regard the process of integration as such as a research topic of its own. There seems to be a general reluctance to apply (truly) interdisciplinary methodology because this is tedious and few, immediate incentives are experienced.


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