THE CALIBRATION OF INCOMPLETE DEMAND SYSTEMS IN QUANTITATIVE ANALYSIS

We introduce an easily implemented and flexible calibration technique for partial demand systems, combining recent developments in incomplete demand systems and a set of restrictions conditioned on the available elasticity estimates. The technique accommodates various degrees of knowledge on cross-price elasticities, satisfies curvature restrictions, and allows the recovery of an exact welfare measure for policy analysis. The technique is illustrated with a partial demand system for food consumption in Korea for different states of knowledge on cross-price effects. The consumer welfare impact of food and agricultural trade liberalization is measured.calibration, exact welfare measure, incomplete demand systems, policy analysis., Demand and Price Analysis,

Reconnaissance de certains caractères chimiques des eaux souterraines des séries carbonatées karstiques dévono--carbonifères de Chine méridoniale

L'étude porte sur un magasin aquifère calcaréo-dolomitique très karstifié (karst à pitons ou tourelles) d'une région à climat tropical humide de la vallée de Li-Jiang.L'échantillonnage hydrochimique concerne les zones saturée et non saturée de différents secteurs du karst.La détermination des pressions de CO2 et des coefficients de saturation par rapport à la calcite ont fait l'objet d'une attention particulière. Les concentrations en calcium et bicarbonates (éléments prépondérants) varient respectivement dans les intervalles 3,1 à 4,7 et 2,5 à 4,8 mé.l-1.La plus grande partie des échantillons de la zone saturée est en équilibre avec la calcite et la dolomite, sous des pressions de CO2 de l'ordre de 1 à 2.10-2 atm.Les eaux de la zone non saturée sont celles de différents suintements recueillis au plafond d'une galerie naturelle. Elles se distinguent par une inégalité entre les teneurs en bicarbonates et en calcium, interprétée comme étant due à des échanges de bases avec les résidus de colmatage des fissures.Les résultats hydrochimiques font supposer l'existence, dans le karsts de plusieurs domaines aquifères liés à la morphologie, interconnectés, avec drainage général par le Li-Jiang.This paper deals with a research program aimed at studying the hydrogeologic properties of the water-rich carbonate rocks in Southern China. We focus our attention on the Guilin area (Guangxi province). Our results concern the hydrochemistry and we show how a study of time- and space-variations in the chemical composition of groundwater (saturated and unsaturated zone) may help in understanding the hydrodynamic conditions in a karstic aquifer.The Guilin karstic area is mainly composed of a limestone and dolomitic limestone series extending in age from Mid-Devonian to early Triassic, reaching 3 000 m in thickness. In the Li-Jiang valley, the quaternary caver (alluvial deposits) is 10 to 20 meters thick. Geomorphology is named "tower karst", as it may be observed in various tropical regions. In fact, two different types of landform appear : the "fonglin" (peak forest) and the "fongchong" (peak cluster). In the former, isolated peaks (mean altitude : 250-300 m) rise in the plain (altitude around 150 m). In the latter, the peaks join together and delimit closed depressions (attitude up to 600 m in the Guilin area). Deep karstification is as important as surface karstification, which is related to the tectonic context (rocks are intensely fractured), to the subtropical wet climate (mean annual rainfall : 1 900 mm) and also to intense groundwater circulation.Our hydrochemical study has been carried out on various types of water points (springs, sinkholes, large diameter wells, boreholes, an underground river, oozing points from the unsaturated zone). They are located in both the fonglin and the fongchong area, but the highest density is close to the contact fine between the two landforms. The chemical analyses are interpreted in three steps :1) calculation (if possible) of the saturation coefficient relative to calcite and dolomite and of the CO2 equilibrium pressure,2) study of time variations in the composition of water sampled at oozing points from the unsaturated zone and,3) statistic study of space variations in the composition of water sampled at alt points.Hydrochemistry is dominated by Ca2+ and HCO3- ions. Except for two aberrant points (probably resulting from a mixture with surface water), Ca2+ and HCO3- concentration varies in a fairly narrow range (respectively 3.12-4.72 meq.l-1 and 2.53-4.80 mea.l-1). Most of samples from the saturated zone are close to equilibrium with calcite and often with dolomite, under CO2 pressures about 0.01-0.02 atm. Small scale variations in lithology (presence of dolomite) and in CO2 pressure may therefore explain space variations in hydrochemistry and enable waters of the same origin to be identified.The study of the unsaturated zone consists in sampling the water at three oozing points located in three fractures of the roof of a natural cave. Althrough the points are quite near to each other, water composition differs clearly between them. The most interesting result though is provided by the following experiment. One of the three points was initially dry. The flow occurred when breaking the concretion obstructing it. For six hours we studied the discharge and the water-composition variations at that point. The initial value of the discharge (6 ml.mn-1) rapidly decreases and reaches its stable value (4 ml.mn-1) after 1 h 30 min. Ca2+, Mg2+, Na+, K+ and HCO3- concentration show erratic variations, but the fact that Na+ and K+ concentration are linked suggests that these fluctuations are related to adsorption-desorption phenomena. It should be noticed that SO42- concentration is not erratic : it decreases from 0.44 meq.l-1 and reaches a stable value (0.08 meq.l-1) after four hours, i.e. much later than the discharge. This proves that the oozing point yields water from two different origins : a small reservoir and a network of connected fractures reaching a given potential boundary, both being initially static.The statistic study of space variations identifies a mountain aquifer, in the Fongchong zone, and proves that relationships do exist between points which may be located quite far apart. Such relationships should be discussed within the tectonic setting : it has been shown that fracturation develops mainly in three directions (N000-020, N060-080, N120-130); the fracture opening is maximum in the N060-080 direction which corresponds to anormal and strike-slip faults. An open fracture in that direction, joining two points, may explain the relation between them. It also appears that the water composition of springs in the plain, far from the contact fine with the fongchong zone, may be similar to the fongchong one. This proves that water from the fongchong does not only yield springs on the contact fine between fonglin and fongchong. Thus, a groundwater flow occurs from fongchong to fonglin and the hydraulic boundary conditions between the two landforms way be very complex.Finally, we propose the most probable flow pattern in the area studied. The various elements (unsaturated zone, mountain karst aquifer, fongchong aquifer, deep plain aquifer, surface plain aquifer) appear to be closely linked. Further work is underway, in order to estimate the depth of karstification, to identify the groundwater flow more precisely and to quantify if

Hydrological impacts of climate change at catchment scale : a case study in the Grand-Duchy of Luxembourg

As a consequence of an increase of days with westerly atmospheric fluxes, bringing humid air masses from the Atlantic Ocean to Western Europe, important changes in the annual and seasonal distribution of rainfall have been observed over the past 150 years. Annual rainfall totals observed during the second half of the 19th century were less important than those observed during the second half of the 20th century. Moreover, during the past 50 years winter rainfall totals have significantly increased, while summer rainfall totals have been decreasing. Streamflow observations through the second half of the 20th century have shown a significant increase of winter maximum daily streamflow, in reaction to the winter rainfall increase. The modelling of the streamflow under the 19th century climatological conditions suggests that since then, the number of winter flood days has increased, while the occurrence of summer flood days has decreased. Moreover, high floods appear to have been more frequent in the second half of the 20th century

Geological and Hydrogeological Characterization of Springs in a DSGSD Context (Rodoretto Valley – NW Italian Alps)

As continuous groundwater monitoring in the upper sector of Rodoretto Valley (Germanasca Valley, Italian Western Alps) is hampered by logistical problem of data collection during winter and spring months, the only tools currently available to derive hydrogeological information are non-continuous and non-long-term dataset of spring discharge (Q), temperature (T) and electrical conductivity (EC). In order to quantity aquifer groundwater reserve, available Q dataset of a small mountain spring (Spring 1 CB) was investigated by applying the analytical solutions developed by Boussinesq (J Math Pure Appl 10:5–78, 1904) and Maillet (Essais dı’hydraulique souterraine et fluviale, vol 1. Herman et Cie, Paris, 1905); T and EC datasets were also used to provide qualitative information about the nature of the aquifer that supplies the spring. The outcomes of the elaborations highlighted the limits of applicability of these methods in the presence of a non-continuous Q dataset: both Boussinesq (J Math Pure Appl 10:5–78, 1904) and Maillet (Essais dı’hydraulique souterraine et fluviale, vol 1. Herman et Cie, Paris, 1905) estimated that discharge values as a function of recession time were found to be consistently lower than the available discharge ones and the estimated groundwater volumes stored over time above the spring level turned out to be underestimated. Continuous (hourly value) and long-term Q, EC and T values are, therefore, needful to correctly quantify and to make a proper management of groundwater resources in mountain areas

Sur le rôle de la fracturation dans l'organisation de certains phénomènes karstiques souterrains

RÉSUMÉ L'observation directe des galeries karstiques fossiles ou actives montre dans bien des cas que celles-ci s'alignent sur certaines fractures, ou qu'elles sont très proches, par leurs directions, des orientations de certaines familles de discontinuités. Le problème qui se pose est donc de reconnaître si la nature spécifique d'une fracture a une influence sur son processus de karstification. Sur ces bases, et à l'échelle régionale d'un système karstique, ont été analysées d'une part, les directions structurales (longueurs, nombre et nature structurale des familles de fractures, répartition spatiale des axes de déformation de chaque phase tectonique) et les directions des réseaux karstiques (développement linéaire des galeries selon leurs directions). La confrontation de ces différentes données montre que le facteur prépondérant dans la sélection des fractures est leur réactivation mécanique au cours de mouvements tectoniques successifs. Ainsi, les fractures qui ont une direction suborlhogonale à l'allongement X de chaque phase (compression ou distension) bénéficieront de celle réactivation, ce qui aura pour conséquence : — soit de maintenir une direction relativement constante aux axes de drainage du karsl au cours de son évolution (X constant en direction quelle que soit la phase) ; — soit de modifier celte direction (X variable), auquel cas les directions préférentielles de creusement du karst varient au cours de l'évolution de ce dernier. Il en résulte que les drains karstiques peuvent présenter des changements de direction, ce qui est le cas dans l'exemple traité (Bassin karstique du Haut-Vidourle, Gard) où les réseaux fossiles et actifs ont des directions variant de 90°.Grillot J.-C., Drogue C. Sur le rôle de la fracturation dans l'organisation de certains phénomènes karstiques souterrains. In: Norois, n°95 bis, Novembre 1977. Karstologie. pp. 11-22

Température et phénomènes biochimiques dans la dissolution du calcaire

Abstract Generally, it is admitted that the karstification phenomenous has a great activity in cold regions. But it is shown that the pressure of carbonic gas has a most importance in the atmosphere than, it has in the temperature of the solubility of the gas below water. Waters are very corrosive in hot and wet climates.Drogue C., Plegat R. Température et phénomènes biochimiques dans la dissolution du calcaire . In: Bulletin de l'Association de géographes français, N°389-390, 48e année, Mai-juin 1971. pp. 235-240