Continental Intercalary Research Articles

Piezometric variation of the water table in the the Municipality of El-Oued, south-east Algeria

Municipality of El-Oued has been confronted with the phenomenon of the upwelling of water for several years and without almost any cease to become more extensive each year. This phenomenon took very alarming dimensions the last twenty years. The use of the deep layers water (the Continental intercalary and the Final Complex) in an excessive way considerably increased the volume of the water input, as well as the absence of a natural discharge system for the rejections of wastewater, are the principal causes of this ecological imbalance. Contributing to the deterioration of the palm trees, the inundation of (Ghouts) causes mortal consequences at the level of environment, agriculture, the economy and the health of Municipality of El-Oued.The piezometric variation of the water table has shown that in the areas of upwelling groundwater; correspond to piezometric depressions which has favored the accumulation and especially of the waste water.

Geochemical characterization the waters of Foggaras the Continental Intercalary Aquifer of Timinoune region (south west Algeria)

The study of the Continental Intercalary (C.I) groundwater of the region of Timimoune (southwestern Algeria), based on physico-chemical data (major elements), allowed to understand the geochemistry of foggaras water. The aquifer is contained in the formations of the Lower Cretaceous (Albian and Barremian). The waters are strongly mineralized with an average value 2g / l.The waters have a clear predominance of facies chlorinated-sodium. The risk is high to excessive soil salinization, and the risk of medium alkalinity to very high. Statistical analysis led us to reach two conclusions, the first is that, variable electrical conductivity (EC), dry residue (RS), Na + , Ca2 + , Cl - , SO4 -- , mineralization, are best correlated and responsible the signing of the mineral load of water, the second is that the nitrate ion (NO3 - ) opposite to the above-mentioned variables mark its anthropogenic origin. Keywords: Continental Intercalary, mineralization, salinity, PCA, Nitrate

Cleanup and valuation of waters of the aquifer of M’zab Valley (Algeria)

Abstract The M’zab valley is a hyper arid region of average rainfall not exceeding 100 mm per year. However, the rare floods that occur in M’zab River drain large volumes of surface water. Thanks to the genius of the local population, traditional dams were made for artificial recharge of groundwater. Grace of traditional wells drilled in the valley, farmers irrigate their palm groves and gardens. However, since more than half a century, the contribution of deep drilling for the exploitation of the aquifer of the Continental Intercalary posed environmental problems. On the basis of investigations and surveys of the local population during the years 2010, 2011, 2012 and 2013, it appears that these modern techniques in water catchment caused harmful consequences to the region like the rising of water consumption, pollution of groundwater and soil salinity. Solutions and recommendations are outlined in this article.

Temperature and radon-222 as tracer of groundwater flow: application to El Hamma geothermal aquifer system, southeastern Tunisia

Hydrogeological and hydrochemical investigations were applied to explain geothermal groundwater flow factors controlling groundwater mineralization, and 222Rn concentrations were controlled using RAD7-H2O in El Hamma aquifer system, southeastern Tunisia. Nineteen geothermal water samples were collected from different locations (thermal baths and deep wells). Physical parameters (EC, pH, TDS, T) were measured, and major ions were analyzed. Hydrogeochemical modeling and thermal parameters reveal that groundwater from El Hamma aquifer system has several origins. The first type was characterized by a hot temperature >55 °C with a chemical facies Na-Mg-Ca-SO4-Cl. This type characterizes lower cretaceous deep water (continental intercalary aquifer). The second water type was dominated by Na-Ca-Cl-SO4 facies with a temperature <45 °C and represents the superficial aquifer. However, Ca-SO4-Na-Cl-Mg is the third water type which is characterized by mixed water from deep and shallow water with a temperature ranging from 45 to 55 °C. Shallow aquifer displays higher 222Rn concentration (677 to 2903 Bq/m3). However, deep water from continental intercalary displays relatively a low radon concentration (203 to 1100 Bq/m3). Compared to Rn-222 activity in some countries, radon concentration in El Hamma thermal aquifer system has a medium value controlled by structures, porosity, and permeability of aquifers. Variographic analysis and ordinary kriging techniques were used to map temperature spatial variability in the study area. Geostatiscal techniques in addition to geological data and radon activities confirm the existence of vertical communication between continental intercalary aquifer and superficial Senonian aquifer through vertical faults system.

Estimation and condition of groundwater recharge in semiarid zone: example from the Ksour Ridge, NW Algeria

In a recharge area characterized by a semiarid or arid climate and a low annual rainfall, aquifers can be hardly recharged adequately, as it was demonstrated by classical monthly hydrological balance computations. The methodology proposed in this work relies on spatial and temporal interpolation of scarce climatic data. This methodology can be used to determine the recharge flow of aquifers in these zones. The AinSefra’s syncline (Western Saharan Atlas, Southwest Algeria) includes the sandstone aquifers of Continental Intercalary and the Plio-Quaternary layers. It forms an excellent example for this application. Three years with different annual rainfalls are chosen in this application: 1983 as dry year, 2006 as average year, and 2008 as humid one. This application requires information about the soil nature, the surface, and the altitude of the recharge areas. The rainfall and the recharge flow of aquifers indicate that the principal recharge areas are the Jurassic outcrops in the humid years when the annual rainfall exceeds 300 mm.

Scaling of the potable water network of the Touggourt city (Algeria)

With rainfall not exceeding 100 mm/y, the Touggourt region is supplied by the groundwater from the Intercalary Continental aquifer. The needs of irrigation and potable water are met by deep drillings that capture the water of the Intercalary Continental aquifer. It is a fossil water whose temperature is source around 60°C and a mineralization exceeding 2 g/L, which has led to the formation of tartar deposits in the supply network of potable water. The investigations conducted in 2004, 2005, 2007, 2009, and 2010 in the Oued Righ valley reveal the seriousness of the phenomenon of scaling and the consequences on the distribution of water in the Touggourt city.

The Mzab foggara: an original technique for collecting the water rising

Abstract This paper describes for the first time an original foggara, different from the classical foggara (foggara of Gourara) which collects water from the Intercalary Continental aquifer. Located in the middle of the Mzab River, this hydraulic system called the Mzab foggara is intended to exploit the flood waters. Two missions were carried in 2009 and 2010 in the Mzab Valley to describe the hydraulic system. The Mzab foggara constitutes of a gallery of ovoid form 200 m long equipped with 9 air shafts and a 900 m long seguia. The foggara of the Mzab River can drain water flow of 5 m3·s-1 to irrigate western part of the palm plantation of Ghardaia (located 600 km south of Algiers).

Properties of geothermal resources in Kebilli region, Southwestern Tunisia

The Kebilli region is located in the Southwestern part of Tunisia, and is characterized by the presence of deep and shallow geothermal systems (continental intercalary and complex terminal). Chemical and isotopic contents are used to classify the type and determine the origin of thermal water. An evaluation of reservoir temperature and a possible geothermal fluid mixing are also carried out. Both continental intercalary-deep aquifer and complex terminal-shallow aquifer are of Na–(Ca)–Cl–(SO4) mixed water type. The use of different geothermometers and the computation of saturation indexes for different solid phases suggests that the thermal reservoir temperature of the continental intercalary is between 92 and 105 °C, while the fluid temperature from the shallow complex terminal aquifer ranges from 50 to 75 °C. Also, the isotopic data indicates the old origin of all groundwater of Southwestern Tunisia. Mixing effects characterizing the continental intercalary and the complex terminal aquifers were identified using δ2H and δ18O relationship. It appears that the upward movement of thermal water from the deep aquifer to shallow ones is probably due to the abundant fractures in the research area.

Hydrochemistry and geothermometry of thermal groundwater of southeastern Tunisia (Gabes region)

Given the vital importance of water and energy in desert regions, we undertook a study dealing with the deep reservoirs in Gabes area, which is located in the southeastern part of Tunisia. Geothermal resources are taken from the Intercalary Continental [or Continental Intercalaire (CI)], known as the largest deep aquifer in Tunisia and are used in a number of applications, mainly in agriculture. Previous investigations performed on the thermal waters of this area focused on the genesis of the deep waters with regard to the thermal features of geothermal reservoirs. A more detailed investigation has been carried out, considering both deep and shallow waters. In order to estimate the potential temperatures of deep reservoir in the Gabes area, we developed a synthetic study including chemical geothermometers, multiple mineral equilibrium approach, and other approaches. Chemical types of the thermal waters and effects of mixing between shallow cold waters with deep thermal waters were also discussed. In fact, the application of Na–K–Mg diagram relative to deep geothermal reservoir capitulate estimated temperatures (about 90°C). In addition, the multiple mineral equilibrium approach submits a similar estimated temperature ranging between 65 and 70°C, showing a disequilibrium status which indicates a possibly mixing with surface water. Indeed, wells exploiting the CI aquifer in the south part of the studied area showed the same characteristics, corroborating the reliability of the applied methods.

Impact of Integrated Clean Energy on the Future of the Mediterranean Exploitation of albian geothermal water in South Algeria

Abstract The Intercalary Continental aquifer generally called Albian aquifer constitutes the main geothermal resource in South Algeria. Additionally it represents the biggest water reserve in the word. Albian aquifer is used since centuries, especially in the areas where it levels like Tidikelt Touat and Gourara. But however in other areas where this aquifer is deep and whose water is hot, the exploitation of the aquifer is rather difficult. As the only geothermal resource in southern Algeria, the Albian aquifer has a lot of interest from geothermal point of view; therefore good knowledge of the different routes of its exploitations is necessary to facilitate future applications of geothermal in the Saharan regions. The present article gives an overview about various modes of exploitation of the Intercalary Continental aquifer and the major problems which have occurred during exploitation. Finally is added discussion about the main applications of geothermal energy in South Algeria based on projects completed or in progress.

New Journey to the Western Sahara, 1935-1936

I DESCRIBED in the Geogr. Journal, June 1936, how I had to give up in the spring of the year 1935 the idea of crossing the central Tanezruft. I regretted this more especially as it was a vast, still quite unknown region, which left a sufficiently wide gap in our knowledge to preclude even general conclusions. Geological exploration of the area alone would permit a structural sketch of the Western Sahara to be made, by substantiating or by invalidating the hypothesis which I propounded last year concerning the eastern termination of the Arawan syncline. On the occasion of my first visit to Taudeni I was struck by the trend of the Westphalian and Dinantian outcrops which spread out fanwise from a southern base and disappeared in the east under the intercalary Continental. I guessed that the same might well be the case with the other components of the Primary Series and that, in consequence, the Arawan syncline formed a loop to the north-east under the Tanezruft, as it formed one to the southwest on the Mauritanian plateaux. If this supposition were proved to be correct, it involved a prolongation of the crystalline ridge of the Eglab under the Tanezruft, the fusion of this ridge with the Central Massif and consequently a radical independence of the two great primary sedimentation basins of the west, namely, the syncline of Tinduf and the Tassilian basin in the north, and the synclinal trough of Arawan in the south. In the course of this winter I was able to complete my previous observations. In the month of November I935 I proceeded rapidly to the intersection of the Trans-Saharan route and the Sudanese frontier, at which point on November 20 began the camel journey which was to end at Adrar (Tuat) on i8 March I936. I proceeded first of all to Taudeni, via Tagnut and El Gettara, and then to Um el Assel, Tufurin and Mzerreb, at the edge of the Hank (I5 December 1935). From there I pushed on to the north across the dunes of Igidi and the crystalline zones of Karet and Yetti, as far as Tinduf (December 25), crossing the Primary Series on the southern edge of the syncline of Tinduf. The return from Tinduf to In Daguber (27 January I936) was made by a route farther east as far as Taudeni (Shegga, Tufurin, Taghmanant). On February 3 Lieutenant Brandstetter and I left In Daguber to cross the width of the Tanezruft by camel. On the i4th we reached the small Southern Algerian post of Wallen. Geologically speaking, I was disappointed. From Sobti to Wallen, a distance of nearly 400 kilometres, there was not a single outcrop of crystalline rock; nothing but an enormous plateau reg resting on a hammada of Continental formation. The compact part of this hammada, which farther west (Hank, Igidi, etc.) appears only in the form of evidential fragments, must have had an edge which could be reached by marching west. We were consequently obliged to recommence the crossing in the opposite direction and to plunge into the Erg Shech, which we had to cross from side to side in order to discover finally, beyond Bir el Deheb, in the neighbourhood of Grizim, a