the effect of hydrogeological conditions on variability and dynamic of groundwater recharge in a carbonate aquifer at local scale summary groundwater recharge in fractured karstic aquifers is particularly difficult to quantify due to the rock mass s heterogeneity and complexity that include preferential flow paths along karst conduits the present study s major goals were to assess how the changes in lithology as well as the fractured karst systems influence the flow mechanism in the unsaturated zone and to define the spatial variation of the groundwater recharge at local scale the study area is located within the fractured carbonate western mountain aquifer yarkon taninim west of the city of jerusalem at the ein karem ek production well field field monitoring included groundwater level observations in nine locations in the study area during years 1990 2014 the measured groundwater level series were analyzed with the aid of one dimensional dual permeability numerical model of water flow in variably saturated fractured porous media which was calibrated and used to estimate groundwater recharge at nine locations the recharge values exhibit significant spatial and temporal variation with mean and standard deviation values of 216 and 113 mm year respectively based on simulations relationships were established between precipitation and groundwater recharge in each of the nine studied sites and compared with similar ones obtained in earlier regional studies simulations show that fast and slow flow paths conditions also influence annual cumulative groundwater recharge dynamic in areas where fast flow paths exist most of the groundwater recharge occurs during the rainy season 60 80 from the total recharge for the tested years while in locations with slow flow path conditions the recharge rate stays relatively constant with a close to linear pattern and continues during summer

holocene sea surface temperature and sea ice extent in the okhotsk and bering seas accurate prediction of future climate requires an understanding of the mechanisms of the holocene climate however the driving forces mechanisms and processes of climate change in the holocene associated with different time scales remain unclear we investigated the drivers of holocene sea surface temperature sst and sea ice extent in the north pacific ocean and the okhotsk and bering seas as inferred from sediment core records by using the alkenone unsaturation index as a biomarker of sst and abundances of sea ice related diatoms f cylindrus and f oceanica as an indicator of sea ice extent to explore controlling mechanisms in the high latitude pacific temporal changes in alkenone content suggest that alkenone production was relatively high during the middle holocene in the okhotsk sea and the western north pacific but highest in the late holocene in the eastern bering sea and the eastern north pacific the holocene variations of alkenone ssts at sites near kamchatka in the northwest pacific as well as in the western and eastern regions of the bering sea and in the eastern north pacific track the changes of holocene summer insolation at 50 n but at other sites in the western north pacific in the southern okhotsk sea and the eastern bering sea they do not in addition to insolation other atmosphere and ocean climate drivers such as sea ice distribution and changes in the position and activity of the aleutian low may have systematically influenced the timing and magnitude of warming and cooling during the holocene within the subarctic north pacific periods of high sea ice extent in both the okhotsk and bering seas may correspond to some periods of frequent or strong winter spring dust storms in the mongolian gobi desert particularly one centered at 4 3 thousand years before present kyr bp variation in storm activity in the mongolian gobi desert region may reflect changes in the strength and positions of the aleutian low and siberian high we suggest that periods of eastward displacement or increased intensity of the aleutian low correspond with times of increased extent of sea ice in the western okhotsk sea and eastern bering sea

drawdown interval analysis a method of determining the parameters of shallow conduit flow carbonate aquifers from pumping tests in shallow conduit flow scf carbonate aquifers the nature of the void space and groundwater flow differs from that of granular aquifers in that the voids are solution conduits often of large size and flow is generally non darcy these and other characteristics of scf aquifers preclude the application of pumping test analysis methods based on the diffusion equation the drawdown interval analysis dia method which is consistent with a conceptual model of the scf aquifer provides estimates of aquifer parameters using both direct calculation and simulation approaches application of the dia method to two wells yielded parameter values which are consistent with the hydrogeologic setting of the wells

applications of organic geochemistry to paleolimnological reconstructions a summary of examples from the laurentian great lakes the organic matter content of lake sediments contains information that helps to reconstruct past environmental conditions evaluate histories of climate change and assess impacts of humans on local ecosystems the elemental isotopic and molecular compositions of organic matter buried in sediment provide evidence of the biota that have lived in a lake and its catchment area and they serve as proxies of organic matter delivery and accumulation sedimentary records from the north american great lakes provide examples of applications of organic geochemistry to paleolimnological reconstructions the records of these lakes date from retreat of the laurentide ice sheet around 12 ka include the mid holocene hypsithermal and show consequences of recent human changes low corg ntotal ratios indicate that most of the sediment organic matter in the great lakes is from algal production yet changes in biomarker molecule compositions also show that varying amounts of land plant organic matter have been delivered to the lakes elevated algal productivity that accompanies nutrient enrichments of lake waters is recorded as excursions to less negative 13c values in the organic matter of sediments that were deposited in the 1960s and 1970s increased organic carbon mass accumulation rates mirror the isotopic excursions in most parts of the great lakes accumulations of petroleum residues and pyrogenic polycyclic aromatic hydrocarbons in sediments identify fluvial and eolian delivery of organic matter components to different parts of the great lakes emerging applications of multiple and novel organic geochemical proxies to paleolimnological reconstructions are promising yet some potentially important measurements remain underutilized

wavelet analysis of fuenmayor karst spring san julian de banzo huesca spain fuenmayor spring has been monitored continuously for identification purposes to study the behavior of a karst groundwater system this paper initially deals with linear methods employing system engineering techniques for the analysis and identification of a hydrological system considered as a black box model which disregards information on the internal structure of the aquifer under a linear time invariant hypothesis the application of the simple correlation of spectral analysis and parametric identification of transfer function generated some interesting results in the monitored spring these tools have historically been successful in studying a large number of karst springs and continue to be practical approximations in initial attempts to obtain a draft model because of the nonlinear and nonstationary nature of karst more effective systemic techniques are required to cover certain aspects of analysis that the linear system cannot reveal adequately this paper presents interesting results using fuenmayor spring data collected over almost 10 years to show the ability of wavelet techniques in the identification of a karst spring system

leaf wax lipids as paleovegetational and paleoenvironmental proxies for the chinese loess plateau over the last 170 kyr abstract high resolution records for long chain n alkane and n alkanol biomarkers have been obtained by extraction of sediments from the profiles of luochan 0 36 ka and xunyi 0 170 ka on the chinese loess plateau clp the two records are similar where they overlap over the last 36 ka at xunyi distributions of the n alkane and n alkanol homologues remain relatively constant over the full 170 kyr the n alkanes are characterized by high odd over even carbon number preference and predominance of the c31 n alkane whereas the n alkanols are dominated by even over odd carbon numbers and by the c28 n alkanol an alkane index a i c3l c29 c31 and an alkanol index alc i c30 c28 c30 are both positively related with magnetic susceptibility of the sediment with higher values during interglacials a lipid index l i averaging the normalized alkane and alkanol indices gives a measure of changing vegetation for palaeo environmental construction a further useful index is provided by the 13 c value of the most abundant n alkane c31 after adjustment for the calculated effect of the estimated atmospheric pco2 and precipitation the record of this index over the last 170 kyr which varies from 36 to 32 indicates that the vegetation on the clp has been mainly c3 plants and became even more so in the glacial periods especially mis 6 and 2 as the minor population of warm season grasses c4 favored in interglacial times declined when temperatures fell the lipid distributions and carbon isotope values are in general accord with the pollen and phytolith evidence recorded for the yuan areas of the clp in indicating steppe or meadow steppe vegetation with abundant cold season grasses c3 and some herbs bushes and trees especially in glacial times

investigation of young water inflow in karst aquifers using sf6 cfc 3h he 85kr 39ar and stable isotope components abstract karst aquifers are known for their wide distribution of water transfer velocities from this observation a multiple geochemical tracer approach seems to be particularly well suited to provide a significant assessment of groundwater flows but the choice of adapted tracers is essential in this study several common tracers in karst aquifers such as physicochemical parameters major ions stable isotopes and 13c to more specific tracers such as dating tracers 14c 3h 3h 3he cfc 12 sf6 and 85kr and 39ar were used in a fractured karstic carbonated aquifer located in burgundy france the information carried by each tracer and the best sampling strategy are compared on the basis of geochemical monitoring done during several recharge events and over longer time periods months to years this study s results demonstrate that at the seasonal and recharge event time scale the variability of concentrations is low for most tracers due to the broad spectrum of groundwater mixings the tracers used traditionally for the study of karst aquifers i e physicochemical parameters and major ions efficiently describe hydrological processes such as the direct and differed recharge but require being monitored at short time steps during recharge events to be maximized from stable isotopes tritium and cl contents the proportion of the fast direct recharge by the largest porosity was estimated using a binary mixing model the use of tracers such as cfc 12 sf6 and 85kr in karst aquifers provides additional information notably an estimation of apparent age but they require good preliminary knowledge of the karst system to interpret the results suitably the cfc 12 and sf6 methods efficiently determine the apparent age of baseflow but it is preferable to sample the groundwater during the recharge event furthermore these methods are based on different assumptions such as regional enrichment in atmospheric sf6 excess air and flow models among others 85kr and 39ar concentrations can potentially provide a more direct estimation of groundwater residence time conversely the 3h 3he method is inefficient in the karst aquifer for dating due to 3he degassing

miocene phreatomagmatic volcanism at tihany pannonian basin hungary abstract a late miocene 7 56 ma maar volcanic complex tihany maar volcanic complex tmvc is preserved in the pannonian basin and is part of the bakony balaton highland volcanic field base surge and fallout deposits were formed around maars by phreatomagmatic explosions caused by interactions between water saturated sediments and alkali basalt magma carrying peridotite lherzolite xenoliths as well as pyroxene and olivine megacrysts subsequently nested maars functioned as a sediment trap where deposition built up gilbert type delta sequences at the onset of eruption magma began to interact with a moderate amount of groundwater in the water saturated sand as eruption continued phreatomagmatic blasts excavated downward into limestones providing access to abundant karst water and deeper to sandstones and schist both providing large amount of fracture filling water at the surface this wet eruption led to the emplacement of massive tuff breccias by fall surge mudflow and gravity flow deposition the nature of the tmvc maar eruptions and their deposits appears to depend on the hydrological condition of the karst and or fracture filling aquifer which varies seasonally with rainfall and spring runoff the west and east maar volcanoes of tmvc are interpreted to represent low water input from the karst and or fracture filling aquifer summer vent whereas the east maar is interpreted to have formed when abundant karst and or fracture filling water was available spring vent

hydraulic modeling of flood pulses in the middle bussento karst system mbsks unesco cilento global geopark southern italy karst systems provide water for domestic and industrial uses and for generating hydropower but they can also create fluvial hazards such as upstream back flooding and downstream karst flash flood events however these hazards are difficult to foresee due to the complex recharge discharge processes as well as the lack of information on the inside of the system which has often not been completely surveyed by speleologists or explored by boreholes to overcome these difficulties hydro chemical data from the monitoring system in the middle bussento karst system mbsks one of the first experimental karst systems in southern italy were recorded and previously discussed based on shared background in flood karst hydraulic modeling this paper describes the conceptual premises and rationale of a general purpose hydraulic model that is suitable both for the mbsks and for other mediterranean multi recharge mature conduit dominated karst systems to test the reliability of the model simulations of time space behavior and response are performed using natural and artificial flood pulses as tracers considering a pulse as a significant variation in water quantity and or quality the results of the model explain the interactions between allogenic autogenic and anthropogenic recharges from differentiated sources and phreatic conduit systems these results also clarify the overall response of karst springs at typical time scales of flood pulses

conceptual hydrogeological model of flow and transport of dissolved organic carbon in a small jura karst system summary this paper aims at characterizing infiltration and solute transport processes in a karst system during flood events in order to build a conceptual model of hydrogeological functioning the study site is the small karst system of fertans in the french jura soil cover rock matrix and a small spring were monitored to measure hydrological and hydrochemical parameters and particularly a continuous dissolved organic carbon doc signal which is a relevant environmental tracer of fast infiltration we used two combined approaches first from hydrodynamic and hydrochemical data we identified the system structure consistent with a dual porosity scheme and characterized the main processes occurring during flood events second on the basis of this scheme we built a new conceptual hydrogeological model coupled with doc transport to numerically validate the hydrological functioning this modelling approach is based on a rainfall discharge model to simulate spring flow solute transport is modelled using mixing equations including an empirical retardation factor as well as a first order solute decay the model was calibrated and validated on a set of nineteen flood events showing its performances in simulating spring hydrographs and delayed doc signals during flood events with various rainfall intensities we showed that the recharge area of the karst system varied largely with low and high groundwater periods which was attributed to the state of hydraulic connectivity in the unsaturated zone the soil cover appeared to play an important role of mixing and transfer for the recharge water the model simulated the contributions of pre event and event waters during flood events and allowed a better quantification of the available resource it showed in particular that total discharge of some flood events during low water periods is mainly composed of pre event water via piston flow type processes finally this study shows that the mixing model can simulate solute transport correctly taking into account degradation and retardation processes it highlights the need for a quantitative approach on hydrochemical studies of karst systems in order to understand them better

investigating transport properties and turbidity dynamics of a karst aquifer using correlation spectral and wavelet analyses in many places throughout the world drinking water is frequently contaminated by turbidity such turbidity however as representative of particle transport can be used as to trace certain features of particle transport properties in order to investigate the relation between particle and dissolved species transport and hydrodynamics in karst systems correlation and spectral analyses were performed on time series of rainfall input signal and water level specific conductance and turbidity output signals at a karst spring system in the chalk aquifer of the lower seine valley france this system is composed of a spring connected to a sinkhole on the chalk plateau where a small creek enters the subsurface the autocorrelation functions for water level and turbidity showed a short memory effect demonstrating the short duration of the influence of flood events on these two parameters whereas specific conductance representing less mineralized storm derived water had a much longer memory effect these results were interpreted as reflecting the rapid reactivity of the spring to rain events with storage of water in the fissured chalk explaining the longer memory effect for specific conductance than for particles energy spectra computed by fast fourier transform of autocorrelation functions showed a strong structure in the output signals whereas the input signal rainfall was random thus allowing assessment and comparison of system behaviour regarding dissolved and solid transport as well as hydraulics cross correlation functions which allow an assessment of impulse response functions confirmed the low inertia of the system for water level and turbidity and the much higher inertia for specific conductance in addition to the main peak two secondary peaks in the cross correlation functions suggest the existence of additional flowpaths that might involve the contribution of other point source recharge and or delayed infiltration through the clayey surficial formation and solution pipes which could act as epikarst analysis using continuous wavelet spectra allowed a better investigation of the rainfall signal structure and highlighted a strong relationship between turbidity and rainfall which could not be deduced from the energy spectra specific spectral components in water level were isolated and a time domain reconstruction using inverse wavelet transform allowed separation of quick flow and slow flow components

numerical simulation and evaluation of groundwater resources in a fractured chalk aquifer a case study in zinder well field niger groundwater is often a unique water source for agriculture industry and domestic use for local inhabitants in semi arid african continent owing to shortage of surface water and rainfall it is of significance to quantify and assess the groundwater resources for local sustainable development in order to correctly evaluate groundwater resources of zinder well field with fractured media in zinder niger a conceptual model of hydrogeology was set up by a geological and hydrogeological survey for simulating the real conditions a large multi well pumping test with designed pumping rate was conducted in addition a two dimensional finite element transient flow model was developed to simulate groundwater flow at the site results show that generally good agreements have been found between the simulated and observed hydrogeology heads for the test the hydraulic parameters were obtained from the pumping test a 11 year prediction of groundwater resources has been made under three exploitation schemes respectively and it indicates that the well field can offer 7 000 m3 day when the aquifer remains confined an optimal scheme of exploitation is provided

estimation des caracteristiques physiques d aquiferes profonds a partir de l incidence barometrique et des marees terrestres abstract time series analyses are used to investigate the relationship between barometric efficiency earth tides and water level fluctuations in a confined aquifer applied to a limestone confined aquifer in france this method allowed the estimation of porosity storage coefficient and aquifer thickness this case study shows that the method is easily used particularly in the case of limestone confined aquifers where pumping test analyses are difficult and require numerous assumptions

a north to south transect of holocene southeast atlantic continental margin sediments relationship between aerosol transport and compound specific δ13c land plant biomarker and pollen records 1 we examined near surface late holocene deep sea sediments at nine sites on a north south transect from the congo fan 4 s to the cape basin 30 s along the southwest african continental margin contents distribution patterns and molecular stable carbon isotope signatures of long chain n alkanes c27 c33 and n alkanols c22 c32 are indicators of land plant vegetation of different biosynthetic types which can be correlated with concentrations and distributions of pollen taxa in the same sediments calculated clusters of wind trajectories and satellite aerosol index imagery afford information on the source areas for the lipids and pollen on land and their transport pathways to the ocean sites this multidisciplinary approach on an almost continental scale provides clear evidence of latitudinal differences in lipid and pollen composition paralleling the major phytogeographic zonations on the adjacent continent dust and smoke aerosols are mainly derived from the western and central south african hinterland dominated by deserts semi deserts and savannah regions rich in c4 and cam plants the northern sites congo fan area and northern angola basin which get most of their terrestrial material from the congo basin and the angolan highlands may also receive some material from the chad region very little aerosol from the african continent is transported to the most southerly sites in the cape basin as can be expected from the present position of the phytogeographic zones the carbon isotopic signatures of the n alkanes and n alkanols both become isotopically more enriched in 13c from north to south the results of the study suggest that this combination of pollen data and compound specific isotope geochemical proxies can be effectively applied in the reconstruction of past continental phytogeographic developments

studies on groundwater recharge characteristics at a reclaimed land site with an equatorial climate using time series and spectral analyses groundwater recharge studies are essential for investigating the feasibility of using the reclaimed lands in singapore for subsurface storage and recovery of water through time series and spectral analyses net recharge percentages and stress filtering characteristics at the reclaimed land were found to depend strongly on the stress transfer velocity which was a combined function of rainfall pattern and vadose zone thickness based on stress transfer velocity a theory was established to provide logical explanations for the rainfall recharge relationship the observed stress filtering characteristics and the recharge percentage characteristics at the unconfined sandy aquifer although the reclaimed land site has a lithollogically homogeneous soil profile a non uniform recharge pattern was observed to be influenced pronouncedly by the uneven density distribution of bush grasses under a bare soil condition significantly lower recharge percentages were observed for areas under the influence of offshore tides the unconfined sandy aquifer appears to dampen out the wave propagation of offshore tides rapidly within a short distance from the tidal source though it has a fairly straight shoreline and is created from highly compacted sand fills copyright 2006 john wiley sons ltd

sea surface temperature variability and sea ice extent in the subarctic northwest pacific during the past 15 000 years past changes in north pacific sea surface temperatures and sea ice conditions are proposed to play a crucial role in deglacial climate development and ocean circulation but are less well known than from the north atlantic here we present new alkenone based sea surface temperature records from the subarctic northwest pacific and its marginal seas bering sea and sea of okhotsk for the time interval of the last 15 kyr indicating millennial scale sea surface temperature fluctuations similar to short term deglacial climate oscillations known from greenland ice core records past changes in sea ice distribution are derived from relative percentage of specific diatom groups and qualitative assessment of the ip25 biomarker related to sea ice diatoms the deglacial variability in sea ice extent matches the sea surface temperature fluctuations these fluctuations suggest a linkage to deglacial variations in atlantic meridional overturning circulation and a close atmospheric coupling between the north pacific and north atlantic during the holocene the subarctic north pacific is marked by complex sea surface temperature trends which do not support the hypothesis of a holocene seesaw in temperature development between the north atlantic and the north pacific key points millennial scale changes in sst in the north pacific during the last 15 kyr changes in sea ice extent suggest a close coupling to sst fluctuations middle to late holocene ssts show no clear sst trend in the north pacific

quantifying and numerically representing recharge and flow components in a karstified carbonate aquifer karstified carbonate aquifers are highly heterogeneous systems characterized by multiple recharge flow and discharge components the quantification of the relative contribution of these components as well as their numerical representation remains a challenge this paper identifies three recharge components in the time and frequency domain while the analysis in the time domain follows traditional approaches the analysis of the power spectrum allows frequencies associated with specific spectral coefficients and noise types to be distinguished more objectively the analysis follows the presented hypothesis that the different frequency noise components are the result of aquifer heterogeneity transforming the random rainfall input into a sequence of non gaussian signals the distinct signals are then numerically represented in the context of a semidistributed pipe network model in order to simulate recharge flow and discharge of an irish karst catchment more realistically by linking the power spectra of the modeled recharge components with the spectra of the spring discharge the information usually gained by classical performance indicators is significantly widened the modeled spring discharge is well matched in the time and frequency domain yet the different recharge dynamics explain the signal of the aquifer outlet in different noise domains across the spectrum this study demonstrates the conjunctive use of frequency analysis in conceptualization of a hydrological system together with modeling and evaluation

the influence of drought and anthropogenic effects on groundwater levels in orissa india summary investigating the response of groundwater levels to the extreme weather events provides essential information for sustainable planning and management of water resources the aim of this study was to identify and quantify the groundwater level trend of the state orissa india to understand the forcing mechanism of droughts in conjunction with the anthropogenic pressure using the non parametric mann kendall statistical procedure the pre and post monsoon groundwater level records of 1002 monitoring stations during the period 1994 2003 were analyzed the results show that the drawdowns due to deficient rainfall during dry years high temperatures and anthropogenic pressure have not been recovered through the recharge in wet years however this study does not determine whether drought high temperatures or anthropogenic effects have had largest influence on the groundwater levels decline the cases of significant water table declines are higher in number than those expected to occur by chance in the pre monsoon season 59 of the monitoring stations experienced groundwater declines as against 51 in the post monsoon season for the study area as a whole this could be interpreted that the fluctuation is not a part of noise but that a signal is being identified further the trend result showed wide spatial and seasonal differences irrespective of seasons the consolidated rock formation that covers 80 of the geographical area experienced significant water table decline however the semi consolidated and unconsolidated formations experienced water table decline in the pre monsoon summer season only the vulnerable sites where the groundwater level declined significantly were identified so that recharge measures could be taken up

modeling heterogeneity of gravel sand braided stream alluvial aquifers at the facies scale abstract the coarse grained alluvial aquifers are recurrently considered as almost homogeneous and isotropic media nevertheless water flow through these sediments is controlled by internal architecture therefore a better knowledge is necessary to understand the effects of facies heterogeneity on the conductivity magnitude and anisotropy within these aquifers in this work we search interactions at the facies scale within a glacio fluvial aquifer among sedimentary heterogeneity distribution of permeability and anisotropy the case study concerns pleistocene sequences of the ticino basin northern italy where three model blocks dug into real sediments at a quarry site have been investigated at the meter scale these model blocks represent the most diffuse facies associations 1 sand gravel dunes 2 gravel bedforms and 3 poorly sorted mass gravity deposits facies maps with 2 cm resolution were obtained for each block and used to condition 3d geostatistical simulation of the sediment volumes with a hierarchical modification of sisim conductivities of samples were either measured with laboratory tests or estimated with empirical formulas conductivity values were finally introduced as input data into the numerical flow model to compute the upscaled tensor of equivalent conductivity at the model block scale the results of field infiltration tests were used to verify the outcomes of upscaling experiments which identified the primary influence on the most permeable facies open framework gravel on both conductivity magnitude and anisotropy ratio the latter property is unrelated to the abundance of this facies but is controlled by its spatial distribution within the blocks as the connectivity of open framework gravel increases model blocks become more anisotropic on the other hand the low permeable sand facies of dunes do not produce significant anisotropy at the block scale these results show the importance of introducing the hierarchical assemblage of different rank depositional units in conceptual aquifer models in addition we identified the most significant depositional units to forecast the spatial distribution of aquifer heterogeneity at different scales

climatic and hydrological variations during the last 117 166 years in the south of the iberian peninsula from spectral and correlation analyses and continuous wavelet analyses the most complete historical series of instrumental data available spanning more than a century on rainfall temperature and outflow of a karst spring obtained from gauging stations in the south of the iberian peninsula were analysed by means of spectral and correlation analyses and continuous wavelet analyses annual periodicity of the rainfall and temperature distributions was constant over more than 100 years although weaker 6 month periodicities have also been observed as well as rainfall and temperature periodicities of 5 and 2 5 years which have also been recorded in other areas of europe these multiannual scale components can be explained by climatic variations or effects described in the literature in connection with the north atlantic oscillation nao and are likely to be the same as the climate variability at decadal to annual scale detected in several proxy data from geological records no long term trends in the distribution of precipitation and temperature were detected

incorrect when uncorrected reconstructing vegetation history using n alkane biomarkers in loess paleosol sequences a case study from the saxonian loess region germany abstract this study aims at contributing to the reconstruction of the paleoenvironment of the saxonian loess region by investigating sedimentary n alkanes as plant leaf wax derived biomarkers in two loess paleosol sequences lpss namely the gleina and the rottewitz lpss the weichselian paleosols are characterised by n alkane concentration maxima when compared to the loess layers when this coincides with high odd over even predominances oeps this points not only to increased n alkane input and or production but also to increased n alkane preservation in the soils namely in gleysols with water logged edaphic conditions by contrast the buried cambisols reveal low oeps indicating accelerated degradation under aerobic edaphic conditions the n alkane concentrations in the truncated eemian interglacial paleosol are very low this reflects the removal of the formerly n alkane enriched eemian topsoil low n alkane input into the b t s d horizon subsoil horizon of the eemian luvisol and or strong soil organic matter mineralization four investigated n alkane ratios show distinct variations during the weichselian tempting inferences of vegetation changes in terms of varying contributions of tree shrub derived dominated by n c 27 or n c 29 versus grass derived dominated by n c 31 or n c 33 n alkanes however using the oep as a proxy for degradation and considering that n alkane ratios are prone to degradation effects the above interpretation is very likely incorrect degradation can account for most variability of the n alkane ratios applying an endmember model based on a modern n alkane reference dataset allows estimating the contribution of tree shrub versus grass derived n alkanes semi quantitatively these modelling results suggest that both the gleina and the rottewitz lpss were formed under prevailing grassland minor contributions of trees shrubs are only likely for the gleinaer soil complex in rottewitz lps for the top of a brown gleysol in gleina lps and the holocene soil the weichselian vegetation changes as inferred from the uncorrected n alkane ratios are not confirmed overall the n alkane results support the idea that the gleinaer soil complex in gleina and rottewitz lps respectively are not identical but rather are chronostratigraphic equivalents more favourable regional climatic conditions presumably occurred in the southwesterly exposed rottewitz locality and allowed tree shrub vegetation to grow during favourable periods of the weichselian a major shortcoming of the n alkane biomarker method is that only vegetation changes of deciduous woodland to grassland and vice versa can be reconstructed because coniferous trees exhibit by two to three orders of magnitude lower n alkane concentrations

new insights into nitrate dynamics in a karst groundwater system gained from in situ high frequency optical sensor measurements abstract understanding nitrate dynamics in groundwater systems as a function of climatic conditions especially during contrasting patterns of drought and wet cycles is limited by a lack of temporal and spatial data nitrate sensors have the capability for making accurate high frequency measurements of nitrate in situ but have not yet been evaluated for long term use in groundwater wells we measured in situ nitrate continuously in two groundwater monitoring wells one rural and one urban located in the recharge zone of a productive karst aquifer in central texas in order to resolve changes that occur over both short term hourly to daily and long term monthly to yearly periods nitrate concentrations measured as nitrate nitrogen in milligrams per liter mg l during drought conditions showed little or no temporal change as groundwater levels declined during aquifer recharge extremely rapid changes in concentration occurred at both wells as documented by hourly data at both sites nitrate concentrations were affected by recharging surface water as evidenced by nitrate concentrations in groundwater recharge 0 8 1 3 mg l that were similar to previously reported values for regional recharging streams groundwater nitrate concentrations responded differently at urban and rural sites during groundwater recharge concentrations at the rural well approximately 1 0 mg l increased as a result of higher nitrate concentrations in groundwater recharge relative to ambient nitrate concentrations in groundwater whereas concentrations at the urban well approximately 2 7 mg l decreased as a result of the dilution of higher ambient nitrate concentrations relative to those in groundwater recharge notably nitrate concentrations decreased to as low as 0 8 mg l at the urban site during recharge but postrecharge concentrations exceeded 3 0 mg l a return to higher nitrate concentrations postrecharge indicates mobilization of a localized source of elevated nitrate within the urbanized area of the aquifer changes in specific conductance were observed at both sites during groundwater recharge and a significant correlation between specific conductance and nitrate correlation coefficient r 0 455 was evident at the urban site where large 3 fold changes in nitrate occurred nitrate concentrations and specific conductance measured during a depth profile indicated that the water column was generally homogeneous as expected for this karst environment but changes were observed in the most productive zone of the aquifer that might indicate some heterogeneity within the complex network of flow paths resolving the timing and magnitude of changes and characterizing fine scale vertical differences would not be possible using conventional sampling techniques the patterns observed in situ provided new insight into the dynamic nature of nitrate in a karst groundwater system

fluid flow modeling of a coastal fractured karstic aquifer by means of a lumped parameter approach fluid flow and solute transport phenomena in fractured and karstic aquifers remain an open issue that calls the attention of numerous researchers belonging to different disciplinary fields as far as the aspects linked both to shallow and to deep phenomena are concerned the hydrogeologic knowledge of these phenomena proves to be of high importance especially if considered in relationship with water resource exploitation with the problems linked to contamination and the ones linked to urban and industrial development of the territory in the examined area characterized by a dismissed contaminated site the realization of the landfill has required the development of a 3d flow model supported by a detailed local scale geologic model in order to evaluate the effects on groundwater flow and subsequently on contaminant propagation the results of the flow model prove to be coherent with the fractured and karstic nature of the site in that they show at higher depths the presence of a subterranean stream channel that would speed up pollutant propagation the obtained results represent the fundamental basis to implement a transport model that will permit to achieve a more in depth knowledge of the subsoil transport phenomena and therefore to optimize any anthropic intervention that can involve the site

flow in a limestone aquifer as determined from water tracing and water levels in wells abstract the inner bluegrass karst region of central kentucky u s a is a fluviokarst underlain by flat lying slightly argillaceous limestones ordovician water tracing and field observations have shown the aquifer to be divisible into groundwater basins and intervening interbasin areas flow in groundwater basins is in a dendritic system of solution conduits at depths as great as 35 m beneath the surface which often passes beneath surface divides to emerge at low level springs in contrast to interbasin areas in which the flow is shallow and generally parallels surface slopes the availability of relatively dense water level data in an area in which a number of water traces had been conducted allowed a comparison between the configuration of the potentiometric surface and water tracing data the potentiometric surface map was generally consistent with the location of groundwater basins and interbasin areas in addition water levels near streams were found to be controlled by the stream and a few wells indicated perched aquifers the potentiometric surface however failed to show narrow groundwater basins and did not adequately indicate groundwater flow directions previously established by water tracing although well data may furnish valuable supplemental information it is concluded that water tracing is necessary to determine adequately subsurface flow directions in the region and in similar karst aquifers elsewhere

asynchronous evolution of the isotopic composition and amount of precipitation in north china during the holocene revealed by a record of compound specific carbon and hydrogen isotopes of long chain n alkanes from an alpine lake both the timing of the maximum east asian summer monsoon easm intensity in monsoonal china and the environmental significance of the chinese stalagmite oxygen isotopic record delta o 18 have been debated here we present a ca 120 year resolution compound specific carbon delta c 13 and hydrogen sd isotopes of terrestrial long chain n alkanes extracted from a well dated sediment core from an alpine lake in north china our delta c 13 data together with previously reported pollen data from a parallel core demonstrate a humid mid holocene from ca 8 5 ka bp assuming that the climatic humidity of north china is an indicator of the easm intensity then the maximum easm intensity occurred in the mid holocene our sd data reveal a similar long term trend to the delta o 18 record from nearby lianhua cave indicating that the synchronous sd and delta o 18 records faithfully record the sd and delta o 18 of precipitation respectively the most negative sd and delta o 18 values occur in t he early mid holocene from ca 11 5 ka bp this contrast in the timing of isotopic variations demonstrates a complex relationship between the isotopic composition of precipitation and precipitation amount or easm intensity further comparisons indicate a possible linkage between the precipitation amount in north china and the west east thermal gradient in the equatorial pacific in addition the temperature of the moisture source area may play an important role in determining the isotopic composition of precipitation in monsoonal china c 2016 elsevier b v all rights reserved

the impact of climate change human interference scale and modeling uncertainties on the estimation of aquifer properties and river flow components summary within the period 1978 2006 climate change and human interferences produced noticeable impacts on the hydrology of a small watershed known as the beca river basin climate change was characterized by a persistent raise in temperature 0 78 c decade 1 and a drop in the annual rainfall 300 mm decade 1 human interferences included the construction of a dam for electric power generation in 1998 and since then the transference of beca river flows from the dam lake to the adjacent t mega river the impacts on catchment hydrology comprised a decline of aquifer hydraulic conductivity and effective porosity by approximately one order of magnitude related to a water table lowering of about 17 m within the bedrock aquifer composed of weathered and fractured hercynian granites and paleozoic metassediments and of saprolite layers derived therefrom aquifer property estimates were compared across spatial scales namely the beca river and the nested sub basins scale sub basin aquifers are more porous and permeable than the basin aquifer because corresponding hydraulic circuits are shallower comparisons were also made between aquifer properties derived from measured and simulated stream flows which revealed effects of modeling uncertainties on the results river flows also suffered a substantial decrease in the course of climate change and human interference especially the overland flows 4 5 decrease and the base flows 2 3 decrease the inter flows were less affected 1 3 decrease because they were partly fed with water from the aquifer storage which in turn underwent depletion the hydrologic changes in the beca river basin anticipate important impacts on the local use of natural water in this context the aforementioned water table lowering may have caused limited access to shallow groundwater for activities such as crop irrigation from dug wells whereas the severe decline in overland flows and base flows had certainly reduced the availability of surface water for the refilling of dam lakes and of groundwater for the supply of public and private boreholes

patterns of temporal scaling of groundwater level fluctuation summary we studied the fractal scaling behavior of groundwater level fluctuation for various types of aquifers in puerto rico using the methods of 1 detrended fluctuation analysis dfa to examine the monofractality and 2 wavelet transform maximum modulus wtmm to analyze the multifractality the dfa results show that fractals exist in groundwater fluctuations of all the aquifers with scaling patterns that are anti persistent 1 1 5 1 62 0 07 4 wells the multifractal analysis confirmed the need to characterize these highly complex processes with multifractality which originated from the stochastic distribution of the irregularly shaped fluctuations the singularity spectra of the fluctuation processes in each well were site specific we found a general elevational effect with smaller fractal scaling coefficients in the shallower wells except for the northern karst aquifer upper system high spatial variability of fractal scaling of groundwater level fluctuations in the karst aquifer is due to the coupled effects of anthropogenic perturbations precipitation elevation and particularly the high heterogeneous hydrogeological conditions

analysis of intermittent pumping tests in fissured fractal aquifers theory and applications abstract a new formulation of water flow equations for fissured media allows the analysis of drawdowns caused by intermittent pumping which consist of a series of pumping cycles with variable rates and durations simulation of the evolution of dynamic levels in the pumping well and in observation wells by superimposing the effects of irregular pumping over 89 days 125 pumping cycles is satisfactory the study of the variations in the average pumping rate of each cycle allows analysis of the periodic phenomena which occur almost weekly at the lowest water level

a review of molecular organic proxies for examining modern and ancient lacustrine environments molecular organic geochemical proxies are increasingly being utilized to reconstruct past environmental conditions as new tools continue to be discovered and developed to date organic geochemical proxies have been developed mainly for use in marine systems and are widely used in paleoceanography in contrast organic proxies have been less commonly used on lacustrine sedimentary records one reason for this is that the wide range in the physical and chemical properties of lakes complicates application of some organic geochemical proxies in lacustrine settings furthermore in comparison to marine studies presently only a small number of studies have conducted or are currently conducting fundamental research aimed at developing organic geochemical proxies for use in lacustrine settings despite this an increasing number of paleo limnological studies are currently applying organic geochemical techniques to examine present and past environmental conditions in this manuscript we review the use of a number of commonly utilized organic geochemical and isotopic proxies and discuss their potential for environmental reconstruction in quaternary lacustrine deposits

application of multiple approaches to investigate hydraulic connection in multiple aquifers system in coalfield abstract understanding the hydraulic connections between overburden aquifers is key to safe coal mining however accurately identifying such connections remains challenging conventional investigation methods include geophysical investigation pumping test and hydrochemical analysis which are time consuming expensive and cannot determine continuous variations in hydraulic connection in this paper we performed time series analysis for analyzing water level time series data to identify the hydraulic connections between overburden aquifers in a coalfield the proposed method can identify such connections more clearly than hydrochemical methods it is especially useful in areas where an aquifer system is subject to strong perturbations

holocene cyclic climatic variations and the role of the pacific ocean as recorded in varved sediments from northeastern china we present an n alkane and compound specific carbon isotope record of the past 9 ka from the annually laminated sedimentary sequence of lake xiaolongwan northeastern china the n alkane distribution suggests that lake xiaolongwan has undergone a shift from an oligotrophic state with low algal production and little emergent submerged macrophytes in the early holocene to a eutrophic state with high algal production and abundant emergent submerged macrophytes since the middle holocene the pattern of variation observed in the biomarker proxies acl the n alkane average chain length paq aquatic macrophyte versus aquatic macrophyte and terrestrial plant ratio and lptp lake productivity terrigenous organic production is throughout the record similar to that of the total organic carbon the variation of compound specific carbon isotopic values in the middle and short chain alkanes was mainly regulated by lake productivity and the accumulating organic pool through time in this forested region where the vegetation is dominated by c 3 plants the long chain n alkanes c27ec31 are predominantly derived from leaf wax lipids the compound specific d 13 c27e31 value is sensitive to effective precipitation and therefore represents a useful indicator of regional monsoonal precipitation spectral analysis on the d 13 c27e31 time series reveals significant periodicities of 87e89 205e212 1020e1050 and 1750e2041 years on the centennial timescale the quasi periodicities around 88 and 210 years suggest a strong link between solar activity and monsoon rainfall the millennial monsoon cycle in northeastern china is associated with sea surface temperature sst variations in two active centers of the summer monsoon the western pacific subtropical high wpsh and the okhotsk high increasing sst in the subtropical sea may cause a northwards shift of the wpsh which extends the monsoon rain band meiyu to northeastern china and thus increasing rainfall in that region meanwhile decreasing sst in the okhotsk sea may strengthen the okhotsk high bringing more moisture into northeastern china we suggest that the pacific ocean is a main regulator for summer monsoon rainfall in northeastern china at present and at different time scales during the holocene

wet and arid phases in the southeast african tropics since the last glacial maximum plant leaf wax carbon isotopes provide a record of c 3 versus c 4 vegetation a sensitive indicator of aridity from the southeast african tropics since the last glacial maximum wet and arid phases in southeast africa were in phase with conditions in the global tropics from 23 to 11 ka but at the start of the holocene these relationships ended and an antiphase relationship prevailed the abrupt switch from in phase to out of phase conditions may partially be attributed to a southward displacement of the intertropical convergence zone itcz during the last glacial southward displacements of the itcz are also linked to arid conditions in southeast africa during the younger dryas and the little ice age

contribution of correlation and spectral analyses to the regional study of a large karst aquifer charente france the purpose of the study is to demonstrate that correlation and spectral analyses can contribute to the regional study of a large karst aquifer an example is presented for the la rochefoucauld karst aquifer charente france different types of spatially distributed time series provide valuable spatio temporal information for the karst aquifer the available time series consist of the spring flow rates the flow rates at different locations in sinking streams the piezometric levels the electrical conductivity and temperature of the water the atmospheric pressure and the precipitation the analysis of the flow rates at the springs shows that the aquifer empties very slowly and has a large storage capacity hydrodynamic links were established between three of the four rivers flowing on the aquifer and the springs the results also demonstrate the important spatial heterogeneity of the aquifer and indicate that the most rapid flow occurs in the northern part of the aquifer hourly piezometric and electrical conductivity time series indicate that the transmissivity of the aquifer varies when some conductive channels become desaturated during the low water period the delays between the distributed recharge and the piezometric level between the localized river input and the flow rates at the springs and between the electrical conductivities in rivers and the main spring provide information on the travel times in the aquifer the observation of earth tides and barometric effects indicate that this apparently unconfined aquifer has a confined behaviour

optical dating of holocene dune sands from the hulun buir desert northeastern china aeolian deposits from the hulun buir desert of northeastern china are studied with optically stimulated luminescence dating methods to establish the chronology of dune building phases and climatic changes since the last deglaciation our results indicate that wet climate marked by dune stabilization and soil development in the hulun buir desert commenced at 11 ka ago and this early episode of dune stabilization lasted until 4 4 ka ago this optimum climate between 11 and 4 4 ka ago is mostly the response to the strengthened monsoon circulation and increased precipitation in the northern hemisphere the environment generally became arid after 4 4 ka ago but the dry climate was interrupted by three phases of weak soil development occurring at 1 8 1 4 1 2 1 0 and 0 84 0 5 ka ago respectively such short events of dune stabilization were associated with the warm and humid climate in historical time however the present dune mobilization in the hulun buir desert is mainly the result of poor la

hydrogeological investigation of karst system properties by common use of diverse methods a case study of licka jesenica springs in dinaric karst of croatia licka jesenica is a sinking river situated in the dinaric karst environment of the lika region of croatia the two main karst springs veliko vrelo and malo vrelo provide the majority of licka jesenica s water because of the quality and abundance of the water they contain these springs are strategically important to the public water supply previous knowledge regarding the springs karst system has been negligible therefore a bulk hydrogeological research program was conducted with the purposes of establishing protection zones and assessing the springs water supply potential the research work comprised the following methods hydrogeological mapping setting up of monitoring stations for evaluating discharge and water quality time series analyses hydrograph chemograph hydrochemical analyses and geophysical surveys the main results and conclusions of the research include 1 confirmation that both springs drain a common aquifer 2 determination of the highly vulnerable nature of the karst systems 3 identification of the veliko vrelo spring s more direct connection to the aquifer drainage system in comparison to the malo vrelo 4 estimation of the positions and depths of the springs main feeding conduits 5 confirmation of the extent of the geologically presumed catchment area and 6 finally establishment of sanitary protection zones

a frequency domain approach to groundwater recharge estimation in karst this paper presents an alternative method for determining the values of parameters of a groundwater recharge model the phreatic zone of a karst aquifer is considered as the linear and time invariant filter that transforms the input signal of groundwater recharge rates into the output signal of spring discharges similarities between transfer functions of total rainfall rates and transfer functions of groundwater recharge rates are the basis for developing the parametric periodogram depending on parameters of a groundwater recharge model the values of parameters are estimated by minimizing the differences between the parametric periodogram and a periodogram of spring discharges the approximate whittle log likelihood function is the criterion for determining the optimal values of the parameters by using this frequency domain approach groundwater balance calculations are avoided so the method can be applied on unexplored karst aquifers when groundwater balance cannot be achieved without extensive geologic and hydrogeologic investigations the results of the applications on two springs located in the dinaric karst area in croatia are discussed

estimation of layered aquifer diffusivity and river resistance using flood wave response model a convolution equation and a discrete ramp kernel equation for the application of the flood wave response were applied to estimate aquifer diffusivity and river resistance using the groundwater levels of a selected well in the mangyeong river floodplain the aquifer diffusivity and river resistance are the key parameters to explain the hydraulic connection between aquifer and river groundwater level during a zero rainfall period was used so that the effect of rainfall recharge on groundwater level could be neglected selecting an appropriate flood wave and undertaking correction of the preceding recession or trend of the groundwater level and the river stage had to be performed prior to hydrograph matching the observed and calculated groundwater level responses generated by a flood wave response model to the river stage were matched to each other and an optimal value of the aquifer diffusivity and river resistance were obtained the proposed method is an effective and economical means to estimate aquifer diffusivity and river resistance to characterize the hydraulic interaction between groundwater and river

the sea ice extent anomaly in the north pacific and its impact on the east asian summer monsoon rainfall the relationship between extreme anomalies of the spring sea ice extent over the bering sea and the sea of okhotsk and rainfall variability in the east asian summer monsoon was examined through an analysis of observed data and modeling experiments the results show that reduced sea ice extent leads to an enhanced summer monsoon rainfall in southeastern china this relationship is well supported by the background atmospheric circulation changes and the stationary wave dynamics a difference in the 500 hpa geopotential height composed from the ncep ncar reanalysis data and model output between the light and heavy sea ice cases shows an anomalous high in the east asian summer which favors the invasion of a cold air mass into southern china and prevents the east asian summer monsoon from advancing northward hence the mei yu front and its associated rainfall intensify and stay in southeastern china the generation of the summer anomalous high and its interseasonal link to the spring sea ice extent anomalies can be accounted for by the stationary wave dynamics and the land surface process in spring the decrease in sea ice extent forces eastward propagating wave activity flux and causes an anomalous high in europe along with a decrease in precipitation the decreased soil water content results in a higher land surface temperature and more sensible heat flux in summer and this strengthens summer stationary wave activities in europe the eastward propagation of the wave energy and its intensification in east asia are responsible for the anomalous high in the east asian summer in this process the european land surface acts as a bridge linking the spring sea ice extent anomalies with the east asian summer monsoon

the effect of low permeability fault zones on groundwater flow in a compartmentalized system experimental evidence from a carbonate aquifer southern italy the hydrogeological behaviour of fault zones in carbonate aquifers is often neglected in conceptual and numerical models furthermore no information is available regarding the relationships between piezometric levels when significant compartmentalization occurs due to the occurrence of low flow fault zones the aim of this study was to refine the conceptualization of subsurface flow in faulted carbonate aquifers and to analyse relationships between sub basins within a compartmentalized aquifer system in southern italy the interactions between compartments that straddle low flow faults were investigated over four hydrologic years using a statistical approach to compare i the hydraulic heads within two wells located up and down gradient of tectonic discontinuities as well as ii the rainfall and piezometric levels the results of this study suggest that a set of barriers exists between the wells and therefore the total head loss observed between the wells approximately 80 m should be distributed across several aquitards with one aquitard exhibiting a relatively high permeability or low degree of integrity due to slight differences in permeability transient conditions in aquitards can occur over relatively short periods which is in agreement with the results of the statistical data analysis consequently rather than being caused by pure aquitards aquifer system compartmentalization likely results from slight differences in the permeability between lower permeability fault zones and adjacent higher permeability protoliths copyright 2014 john wiley sons ltd

karst flash flood forecasting in the city of nimes southern france in southern france karst flash floods may be the result of two potentially cumulative phenomena floods from highly localized events that mostly occur during autumn and are locally known as cevenol rain events floods exacerbated by recent rainfall events that contributed to saturation of the aquifer before the storm event thereby increasing runoff in any case flash floods occurring in a karst landscape are directly linked to the structure and hydraulic properties of the karst aquifer a methodology was developed for the city of nimes for forecasting these dangerous events based on the study and modelling of karst aquifer response to rain events this work was composed of i definition of how the nimes system functions leading to a conceptual model ii modelling of this conceptual model iii definition of a tool for hazard management presented as an abacus and tested on particular strong rainfall event

influence of environmental parameters on the seismic velocity changes in a clayey mudflow pont bourquin landslide switzerland abstract an earthflow mudflow of a few thousand cubic metres occurred at the toe of the pont bourquin landslide pbl swiss alps in late august 2010 this event was preceded by a drop of about 6 in surface wave velocity dv v determined from ambient vibration records a seismic monitoring system made of three pairs of sensors was re installed across the transportation and accumulation zones of the landslide in october 2011 allowing daily relative changes in seismic velocity to be measured for a period of 4 5 years no similar drop in dv v was observed during this period consistently with the lack of significant landslide acceleration or earthflow mudflow events however the three dv v time series showed periodic and reversible variations in a range 2 to 2 suggesting a probable influence of seasonal parameters they were cross correlated to daily environmental temperature and rainfall and surface displacement time series in the long term yearly scale dv v variations are mainly driven by the temperature with short delays 30 to 50 days indicating that the shallow layer first 2 m controls the dv v variations in the short term the landslide response to precipitations exhibits a small decrease in dv v with a delay of 2 to 5 days in contrast with the displacement rate that almost instantaneously responds to the rainfall the continuous seismic monitoring of pbl using ambient vibrations has proved to be a robust method for getting information at depth with no data gap even during winters the seasonal reversible seismic velocity variations turned out to be in a range lower than the drop observed before the august 2010 earthflow mudflow highlighting the interest of incorporating the dv v technique in monitoring systems

modelling of the functioning of karst aquifers with a reservoir model application to fontaine de vaucluse south of france summary this work deals with a rainfall discharge model applied to a well known karst aquifer a new approach is developed in order to minimize the fitting parameters here some of the model parameters do not result from a simple fitting as it was the case with earlier models i e some of them were assessed from the hydrograph analysis the conceptual model of the functioning is based on a production function based on a simple calculation of effective rainfall and a transfer function consisting of two reservoirs a slow discharge reservoir transfers the low flow and a rapid discharge reservoir feeds the high flow the model has three fitted parameters plus one for its initialisation three parameters are deduced from the hydrograph analysis over the entire time series for example the recession coefficient of the slow discharge reservoir is determined from the hydrodynamic analysis of the recession mangin a 1975 contribution a l etude hydrodynamique des aquiferes karstiques 3eme partie constitution et fonctionnement des aquiferes karstiques annales de speleologie 30 1 210 124 this model was tested over a ten years period on the fontaine de vaucluse french karst system the first hydrological year is used for fitting the model the nine other cycles validate the modelling the good quality of the model is proved by the nash criterion of 92 3 on the validation period moreover the simulation results were validated by a statistical analysis of measured and simulated time series the model successfully simulates both the high and low flow at the same time also it estimates the water volumes available in the different parts of the aquifer and it proposes a management tool capable of predicting the evolution of the discharge in different climate conditions

statistical analyses and modeling approaches to hydrodynamic characteristics in alluvial aquifer this study is aimed at quantifying the difference in aquifer s response to recharge between some different locations in a fan aquifer and a delta aquifer for a preliminary study of revealing mechanisms of water transport in alluvial aquifer the aquifer s response to recharge is statistically quantified with the two viewpoints 1 timing and volume of recharge and 2 time length of aquifer s holding water for the first point a statistical model that links precipitation and groundwater level is introduced and its parameters are identified using correlation analysis our results show that the recharge rate at the toe is higher than that at the apex and at the delta for the second point the concept of memory effect of aquifer is adopted and quantified using the autocorrelation and spectral analyses our results show that the memory effect is longer at the toe of fan than at the apex and thus a temporary increase of water level has about five times as long term influence on subsequent water levels at the toe of the fan as at the apex this study demonstrates that the statistical analyses and modeling of hydrological data are useful for characterizing aquifer s hydrodynamics copyright 2012 john wiley sons ltd

time transgressive onset of the holocene optimum in the east asian monsoon region abstract the east asian summer monsoon affects precipitation and hence vegetation in the densely populated northwest pacific region yet a long standing controversy exists concerning the spatial and temporal dynamics of the holocene optimum ho in the east asian monsoon region here we use a detailed 14 000 year record reconstructing vegetation variations from a strategically selected crater lake from northeast china as well as a compilation of previous paleoclimatic studies to show that the ho began around 6 000 cal a bp in northeast china significantly later than generally recognized by comparing our paleoenvironmental data with holocene vegetation records from other regions of east asia we identified a marked northward shift for the onset of the ho from 10 260 cal a bp in south china to 6 000 cal a bp in northeast china the gradual northward transgression of the vegetation change could be caused by both the temperature and precipitation changes in different regions finally we fitted a regression model of the start of the ho period versus latitude which allowed us to make predictions for the beginning of the ho at different geographical locations this study reveals a strong relationship between latitude and the initiation of the ho and provides a window towards better understanding the forcing of vegetation changes in the east asian monsoon region

time variant cross correlation to assess residence time of water and implication for hydraulics of a sink rise karst system 1 transport rates and residence time in the subsurface are critical parameters for understanding water rock interactions for efficient contaminant remediation this paper presents a methodology for assessing flow and transit time of water through hydrological systems with specific applications to karst systems and implication for hydraulics of a conduit system surrounded by a porous and permeable intergranular matrix a time variant cross correlation function analysis is applied to bivariate time series that characterize mass transfer assuming a stationary system using sliding windows of various sizes we apply the method to 1 year long temperature records in the santa fe river north central florida measured at 1 the river sink where all the incoming surface water drains into a sinkhole 2 sweetwater lake where the river resurges into a 500 m long karst window and 3 the river rise where the water discharges from a first magnitude karst spring results are compared with those obtained using specific conductivity estimated residence time ranges from less than 1 day during floods to more than 15 days during base flow within the 8000 m flow path between the river sink and the river rise results are used to characterize geometric hydraulic and hydrodynamic properties of this sink rise system with strong matrix conduit interactions these properties are critical to the chemical and physical behavior of surface water groundwater mixing our results also have direct implications for sampling strategies and hydrograph separation of many karst systems with different degrees and types of matrix porosity and permeability

δd values of individual n alkanes from terrestrial plants along a climatic gradient implications for the sedimentary biomarker record abstract the compound specific hydrogen isotope composition d of sedimentary n alkanes is increasingly used as a palaeoclimate proxy to explore the origin of the hydrogen isotope signal of n alkanes from higher terrestrial plant biomass in sedimentary organic matter of small lakes we have analysed the n alkane composition and d values of 31 plant biomass samples birch betula beech fagus oak quercus alder alnus hornbeam carpinus and myrtle myrtus as well as non stomata containing sphagnum cladonia and moss from 14 sites along a climatic gradient from northern finland to southern italy eleven of the sites were previously investigated for the n alkane d values in adjacent lake sediments and are compared to the leaf wax n alkane d values the distribution of terrestrial n alkanes in lake sediments was not found to be characteristic of the dominant vegetation around the lake evidently n alkane distributions within the same species at different sites were found to be variable these findings complicate the use of certain n alkane distributions in sediments as a palaeoenvironmental indicator d values of plant biomass n alkanes show a significant positive correlation with the precipitation d values biomass n alkane d values are in general less negative than the associated sedimentary n alkanes of terrestrial origin possibly due to the stronger evapotranspiration during the summer when sampling took place this suggests that n alkanes in leaves show seasonal variations and the sedimentary organic matter receives the lighter isotope signal of the autumn when most leaves are incorporated into the sediment the variability of the d values from non stomata containing plants is much higher than for broadleaf trees since stomata can regulate water loss through evapotranspiration the average chain length acl of n alkanes from deciduous tree leaves increases from north to south with increasing acl the hydrogen isotopic fractionation e between source water and n alkanes also increases our results prove that terrestrial n alkane d values record the d value of precipitation modified by the amount of isotope enrichment in the leaf water due to plant anatomy stomata vs no stomata and site specific meteorological conditions such as evapotranspiration relative humidity and soil moisture therefore terrestrial n alkanes in lake sediments can deliver information on changes in these parameters over geological timescales in lake sediments where aquatic n alkanes such as n c 17 record the lake water d value the isotopic difference between terrestrial and aquatic n alkanes could therefore be used to reconstruct changes in evapotranspiration

impact assessment of grout curtain on the hydraulic behavior in karst based on time a series analysis the construction of a grout curtain in karst is a very common procedure to reduce water loss from a reservoir long term and short term monitoring of water levels was performed on the prevoj dam lazici water reservoir located in the dinarides of western serbia to determine the hydraulic behavior and functionality of the grout curtain in karstic media different approaches of time series analysis were applied based on the long term monitoring and by application of correlation analysis and rescaled partial sums raps water table fluctuations were analyzed to obtain a general trend and relation between piezometers at the immediate zone of grout curtain short term but very frequent monitoring of water table in the reservoir swt and piezometers provided considerably better insight into hydraulic behavior in karstic media the various methods of obtaining results showed that they are all comparative or complementary the higher order partial correlation proved to be significant in the definition of dependence between observed piezometers by removal of possible influences of other adjacent variables piezometers univariate time series were analyzed by the first difference serial dependencies which considerably changed the identification of the seasonal effect on the water table at the water reservoir this was used as a tracer to analyze the influence of the surface water reservoir on the behavior of water table of analyzed piezometers in rock mass an analysis of the shape of hysteresis provided valuable information related to hydraulic behavior in karst media and conditions of the functioning of the grout curtain as a barrier separating the rising limb from the recession limb on hydrographs and presenting adjacent piezometers on correlograms upward and downward from the grout curtain provided an analysis of hysteresis loops based on this analysis there can be better insight of flow circulation in karst functioning of the hydraulic barrier and better focus on certain zones and controlling of water loss from the reservoir

δ13c analyses of individual lignin phenols in quaternary lake sediments a novel proxy for deciphering past terrestrial vegetation changes this study of the sediments from sacred lake mount kenya demonstrates that 13 c analyses of individual lignin phenols can be used to assess past changes in the proportion of c 3 and c 4 plants within different plant groups in the lake catchment vegetation changes resulting from climatic and atmospheric changes since the last glacial maximum can be deduced from specific lignin phenols lignin a major biopolymer in vascular plants differs from n alkyl lipids in 1 its higher specificity and more quantitative representation of vascular plant input and 2 its major transport mechanism into the sediments by fluvial runoff as opposed to the greater importance of eolian transport for leaf waxes and pollen lignin 13 c data support the hypothesis that atmospheric co 2 concentration is an important factor controlling the vegetation in tropical mountain ecosystems and provide additional insights into past changes in vegetation structure specifically the 13 c values of p coumaric acid indicate the persistence of c 4 grasses during the late glacial when the lake level was lower than today suggesting that aridity also played a role in controlling the abundance of c 4 plants

mediterranean flash flood transfer through karstic area karstic aquifers influence flash floods propagation in mediterranean countries near montpellier southern france discharge data are recorded on the coulazou river upstream and downstream of the aumelas causse two gauging stations are used to describe the hydrodynamics of this binary karstic system the first station characterizes the non karstic catchment area the second one is representative of the karstic part of the watershed records since april 2004 are used to understand how the river interacts with a karstic aquifer hydrograph analysis of three flash flood events is described corresponding discharge time series recorded at the two gauging stations are used to describe the modification of the hydrographs by auto and crosscorrelations analyses finally linear system analyses are used to provide the transfer functions of this binary karstic system according to the three flood events characteristics initial conditions volume spatial distribution of rainfall etc theses functions summarize the hydrodynamic behaviour of the system their shapes are indicative of the dynamics of the storage the release and the contribution to surface waters

inverse phase oscillations between the east asian and indian ocean summer monsoons during the last 12 000 years and paleo el nino abstract the inverse phase variations between the east asian and indian ocean summer monsoons on the interannual timescale result from the el nino southern oscillation activity in the tropical pacific which potentially provides a new way for studying paleo enso here we reconstruct a 12 000 yr proxy record for the east asian summer monsoon from 13 c time series of the plant cellulose of the hani peat bog in the northeastern china the comparison of it with the peat proxy record of the indian ocean summer monsoon suggests that the el nino conditions are coincident with strong east asian summer monsoons weak indian summer monsoons and drift ice events in the north atlantic at both orbital and millennial time scales the orbital scale inverse phase relationships between the monsoons indicate the occurrence of a long term enso like pattern confirming the sensitivity of the monsoon systems associated with enso to insolation forcing the nine inverse phase variations on the millennial time scales may suggest the nine el nino like patterns superimposing the long term enso like pattern the inverse phase variations between the monsoons also show close correspondence to the drift ice events at high northern latitudes in every case when the abrupt ice rafted debris events occurred in the north atlantic the inverse phase relationship established and the el nino like pattern occurred in the tropical pacific correspondingly the discussions on the influence of ocean thermohaline circulation on these global linkages have been made

n alkanes and compound carbon isotope records from lake yiheshariwusu in the hulun buir sandy land northeastern china the hulun buir sandy land in northern china is located at the northern limit region of the east asian summer monsoon easm and is therefore sensitive to the extension of the front of the rainfall

groundwater flow system inferred from hydraulic stresses and heads at an underground lpg storage cavern site underground liquefied petroleum gas lpg storage caverns were constructed below the groundwater table to contain pressurized gas by groundwater pressure continuous and regular groundwater monitoring data were used to analyze whether the gas containment condition was satisfied or not the monitoring data included time series analysis of hydraulic heads gas and groundwater pressures and groundwater chemistry through cross correlation analyses of the time series data the major factors causing hydraulic head fluctuation were found to be groundwater recharge from precipitation and cavern gas pressures hydraulic head and hydrochemical data indicate that a fault zone acts as the groundwater recharge zone and water curtain tunnels reduce head fluctuations

biogeochemical evidence of holocene east asian summer and winter monsoon variability from a tropical maar lake in southern china abstract lake huguangyan 21 9 n 110 17 e a maar lake located near the south china sea can provide valuable sedimentary data regarding past changes of the east asian monsoonal system here we used the proxies of toc 13corg 15n and leaf wax n alkane 13c values 13cwax to reconstruct the lake conditions which in turn revealed patterns in monsoonal changes during the holocene two distinct patterns of proxy changes were identified in the sedimentary profile a marked shift in the 13cwax value at 9 2 ka thousand years ago suggests the abrupt disappearance of c4 plants signaling the enhancement of east asian summer monsoon easm between 9 2 and 1 8 ka a nearly pure c3 terrestrial ecosystem was present with the climax at ca 7 6 ka after ca 3 ka fewer tropical species and a reappearance of c4 plants at 1 8 ka indicate a weakened easm in the late holocene the toc concentration and 15n value proxies appear to be associated with lake aquatic production and upwelled nutrient supply and utilization which are modulated by and thus indicative of the strength of the east asian winter monsoon eawm the two eawm records suggest a weakening trend from the early to late holocene with the most significant transition at 6 ka thus the eawm trend was broadly in phase with that of the easm however the marked easm intensification at 9 2 ka occurred within the period of a strong eawm between 10 5 and 6 ka and lagged the monsoonal enhancement as inferred from the dongge cave 18o values our easm records displays an overall arid wet arid pattern which is in phase with the hydrological variability in tropical australia and anti phase with that in the outer tropical andes these phase relationships might be linked to changes in the thermal state of the tropical pacific during the holocene

transition from a warm and dry to a cold and wet climate in ne china across the holocene abstract northeast ne china lies in the northernmost part of the east asian summer monsoon easm region although a series of holocene climatic records have been obtained from lakes and peats in this region the holocene hydrological history and its controls remain unclear more specifically it is currently debated whether ne china experienced a dry or wet climate during the early holocene here we reconstruct changes in mean annual air temperature and peat soil moisture across the last 13 000 year bp using samples from the gushantun and hani peat located in ne china our approach is based on the distribution of bacterial branched glycerol dialkyl glycerol tetraethers brgdgts and the abundance of the archaeal isoprenoidal iso gdgt crenarchaeol using the recently developed peat specific maatpeat temperature calibration we find that ne china experienced a relatively warm early holocene 5 7 c warmer than today followed by a cooling trend towards modern day values during the mid and late holocene moreover crenarchaeol concentrations brgdgt based ph values and the distribution of 6 methyl brgdgts all indicate an increase in soil moisture content from the early to late holocene in both peats which is largely consistent with other data from ne china this trend towards increasing soil moisture wetter conditions across the holocene in ne china records contrasts with the trends observed in other parts of the easm region which exhibit an early and or mid holocene moisture precipitation maximum however the holocene soil moisture variations and temperature moisture relationships warm dry and cold wet observed in ne china are similar to those observed in the core area of arid central asia which is dominated by the westerlies we therefore propose that an increase in the intensity of the westerlies across the holocene driven by increasing winter insolation expanding arctic sea ice extent and the enhanced okhotsk high caused an increase in moisture during the late holocene in ne china

application of modflow for simulating groundwater flow in the trifilia karst aquifer greece karst aquifers can have a complex flow as a result of the formation of large conduits from dissolution features as a result a three dimensional finite difference groundwater flow model equivalent porous media may not apply as the dual porosity nature of karst features and the effects of turbulent flow cannot be directly simulated statistical analysis of karst hydrographs of the trifilia aquifer in greece showed the existence of a slightly karstified mass with high primary porosity that regulates the flow an equivalent porous media model was developed to simulate the trifilia karst aquifer using modflow steady state and transient state calibration gave encouraging results for the equivalent porous media approach which does not consider pipe flow or turbulence detailed hydrogeological research conducted in the area helped define the aquifer hydraulic conductivity zones and extent and flux to from the aquifer only hydraulic conductivity and specific yield were adjusted during calibration as the flux to from the system was considered known and applied as boundary conditions small mean absolute and rms piezometric head error of the model under both steady and transient state conditions were achieved

contribution a l etude des courbes de recession des sources karstiques exemples du pays hellenique abstract a study of the recession curves of the major springs of some systems of karstic aquifers in greece shows that each of these aquifers is unique in respect of its boundary conditions its internal organization and its hydrodynamics differences which result in different forms of recession curves these case studies can therefore form the basis for the prediction of the recession curves of karstic springs and hence for the classification of the systems of aquifers

timing duration and transitions of the last interglacial asian monsoon thorium 230 ages and oxygen isotope ratios of stalagmites from dongge cave china characterize the asian monsoon and low latitude precipitation over the past 160 000 years numerous abrupt changes in 18o 16o values result from changes in tropical and subtropical precipitation driven by insolation and millennial scale circulation shifts the last interglacial monsoon lasted 9 7 1 1 thousand years beginning with an abrupt less than 200 years drop in 18o 16o values 129 3 0 9 thousand years ago and ending with an abrupt less than 300 years rise in 18o 16o values 119 6 0 6 thousand years ago the start coincides with insolation rise and measures of full interglacial conditions indicating that insolation triggered the final rise to full interglacial conditions

time series analyses for karst river interactions assessment case of the coulazou river southern france summary in many karst systems throughout the world numerous karst features facilitate the exchange of water between the surface the vadose zone and the saturated zone of the aquifer these interactions play actually a prominent role in the ground and surface waters circulation this study aims at assessing karst river interactions by the way of flood hydrograph analysis and new tools for time series analysis in this field of research as in many others binary karst system the captured waters of the coulazou river travel through conduits and preferential flow paths in the vadose zone and join the saturated zone of the aquifer this river is an ephemeral river in a mediterranean context where rapid and intense floods occur each year this hydrologic behaviour is appropriate to study the transfer of a flood through a karst area the water level in caves the rainfall all over the karst aquifer catchment area the piezometric level within the karst aquifer and the discharge in the river upstream and downstream of the karst aquifer are measured in order to understand the karst river exchanges during a flood the modification of the surface flows in the river is treated as a linear time invariant system lti system correlation and spectral analyses are used to understand how the lti system dissipates or enhances the flood wave energy for several floods the frequency response function estimations are interpreted in term of flood wave modification through the karst area in this way according to the initial state of the karst river system the autogenic and or allogenic recharge of the aquifer may induce surge flows and a significant karst contribution to surface flows

latest pleistocene and holocene vegetation and climate history inferred from an alpine lacustrine record northwestern yunnan province southwestern china abstract reconstructing past changes of the summer monsoon in southwestern china is key to understanding the paleoclimatic dynamics of the indian summer monsoon southwest monsoon a major tropical system with impacts beyond the region high resolution pollen and conifer stoma data are presented from a sediment core tiancai lake located just below treeline in the hengduan mountains northwestern yunnan province of china these data record changes in vegetation and climate for the latest pleistocene and holocene c the last 12 230 cal yr bp and by comparing these results with the pollen records from the nearby erhai lake and lugu lake a regional climate history in yunnan province can be inferred during the period of 12 230 11 510 cal yr bp open alpine meadow around tiancai lake indicates a relatively cold and dry climate corresponding to the younger dryas cold event yd between 11 510 and 10 000 cal yr bp the vegetation types around tiancai lake changed into picea and abies forest and alpine rhododendron shrubland reflecting increases in the temperature and humidity from 10 000 to 6100 cal yr bp tsuga forest expanded persistently toward tiancai lake indicating further climate changed towards warmer and wetter conditions between 6100 and 3410 cal yr bp tsuga forest was the dominant vegetation type nearest to tiancai lake denoting warm and humid climatic conditions corresponding to the holocene climatic optimum in the northwestern yunnan province tsuga forest in mountains around lugu lake shrank quickly at 3410 cal yr bp reflecting significant decline of humidity since 2930 cal yr bp tsuga forest around tiancai lake shrank gradually indicating a fluctuating decrease of temperature these climatic changes reflect changes of the southwest monsoon namely warm and humid climate indicating strong southwest monsoon cold and dry climate denoting weak southwest monsoon