regional scale assessment of submarine groundwater discharge in ireland combining medium resolution satellite imagery and geochemical tracing techniques abstract this paper sets the foundation for the use of freely available landsat enhanced thematic mapper etm thermal infrared tir imagery in a regional scale assessment of submarine groundwater discharge sgd to coastal waters a comprehensive tiered three step approach is proposed as the most effective and affordable means to determine the spatial extent and scale of sgd from coastal aquifers to the coastal margin as the preliminary step sea surface temperature sst values derived from landsat etm tir are used to successfully detect plumes of colder water eventually associated with sgd in close proximity to the shoreline subsequently potential sites of sgd are linked to geological features on land acting as possible sources by combining within a geographical information system gis mapped temperature anomalies with ancillary on shore spatial datasets describing bedrock geology including aquifer fault lines finally nearshore surveys mapping the activity of 222 rn radon and salinity are carried out to verify the presence of sgd and provide a qualitative assessment of fresh groundwater inputs to the coastal zone practical application of the complete approach in the context of coastal zone management is illustrated through a case study of the republic of ireland as part of this study over 30 previously unidentified links between aquifers on land and the sea are shown along the irish coast hence illustrating the tight coupling between coastal waters and groundwater inputs at an unprecedented spatial scale the study demonstrates the potential of the combined applications of remote sensing methods and geochemical tracing techniques for a cost effective regional scale assessment of groundwater discharge to coastal waters

topographic controls of landslides in rio de janeiro field evidence and modeling landslides are common features in the serra do mar located along the southeastern brazilian coast most of them associated with intense summer storms specially on the soil mantled steep hillslopes around rio de janeiro city where the favelas slums proliferated during the last few decades on february 1996 hundreds of landslides took place in city of rio de janeiro triggered by intense rainstorms since then many studies have been carried out in two experimental river basins in order to investigate the role played by the topographic attributes in controlling the spatial distribution of landslides inside them landslide scars and vegetation cover were mapped using aerial photographs and field observations a detailed digital terrain model 4 m 2 resolution of the basins was generated from which the main topographic attributes were analyzed producing maps for slope hillslope form contributing area and hillslope orientation by comparing these maps with the spatial distribution of the landslide scars for the 1996 event a landslide potential index lpi for the many classes of the different topographic attributes was defined at the same time field experiments with the guelph permeameter were carried out and a variety of scenarios were simulated with the shalstab model a process based mathematical model for the topographic control on shallow landslides the results suggest that most of the landslides triggered in the studied basins were strongly influenced by topography while vegetation cover did affect landslide distribution between the topographic attributes hillslope form and contributing area played a major role in controlling the spatial distribution of landslides therefore any procedure to be used in this environment towards the definition of landslide hazards need to incorporate these topographic attributes d 2003 elsevier b v all rights reserved

the 22 march 2014 oso landslide washington usa abstract the oso washington usa landslide occurred on the morning of saturday 22 march 2014 and claimed the lives of 43 people the landslide began within an 200 m high hillslope comprised of unconsolidated glacial and previous landslide colluvial deposits it continued as a debris avalanche debris flow that rapidly inundated a neighborhood of 35 single family residences an intense three week rainfall that immediately preceded the event most likely played a role in triggering the landslide and other factors that likely contributed to destabilization of the landslide mass include alteration of the local groundwater recharge and hydrogeological regime from previous landsliding weakening and alteration of the landslide mass caused by previous landsliding and changes in stress distribution resulting from removal and deposition of material from earlier landsliding field reconnaissance following the event revealed six distinctive zones and several subzones that are characterized on the basis of geomorphic expression styles of deformation geologic materials and the types size and orientation of vegetation seismic recording of the landslide indicate that the event was marked by several vibration generating episodes of mass movement we hypothesize that the landslide occurred in two stages with the first being a sequential remobilization of existing slide masses from the most recent 2006 landslide and from an ancient slide that triggered a devastating debris avalanche debris flow the second stage involved headward extension into previously unfailed material that occurred in response to unloading and redirection of stresses

evaluating groundwater discharge to tidal rivers based on a rn 222 time series approach abstract the natural flux of groundwater into coastal water bodies has recently been shown to contribute significant quantities of nutrients and trace metals to the coastal ocean groundwater discharge and hyporheic exchange to estuaries and rivers however is frequently overlooked though it often carries a distinctly different chemical signature than surface waters most studies that attempt to quantify this input to rivers use multiple geochemical tracers however these studies are often limited in their spatial and temporal extents because of the labor intensive nature of integrating multiple measurement techniques we describe here a method of using a single tracer 222 rn to rapidly characterize groundwater discharge into tidally influenced rivers and streams in less than one week of fieldwork we determined that of six streams that empty into the indian river lagoon irl florida three eau gallie river turkey creek and main canal did not receive substantial groundwater inputs one canal c 25 canal was dominated by groundwater exchange and the remaining two sebastian river system and crane creek fell somewhere in between for more detailed discharge assessments we focused on the sebastian river system a stratified tidal river estuary during a relatively dry period june and a wet period july in 2008 using time series 222 rn and current velocity measurements we found that groundwater discharge into all three branches of the sebastian river increased by 1 2 orders of magnitude during the wetter period the estimated groundwater flow rates were higher than those reported into the adjacent irl suggesting that discharge into these rivers can be more important than direct discharge into the irl the techniques employed here should work equally well in other river stream systems that experience significant groundwater discharge such assessments would allow area managers to quickly assess the distribution and magnitude of groundwater discharge nature into rivers over large spatial ranges

a large scale landslide and related mechanism a case study in the qazvin rasht freeway iran the manjil landslide occurred after the slope cutting and the removal of the toe buttress 8 july 2013 between 41 400 and 42 200 km section of manjil radbar in the qazvin rasht freeway gilan province iran the occurrences of landslide led to blockage of the freeway a cutting was designed with a width and height of 4 and 6 m respectively and a 5 to 6 m excavation depth within a 120 m line along the slope toe based on the site investigations the landslide was characterized as a complex deep seated landslide displaying composite rotational debris flow moreover extensive field survey subsurface investigation laboratory and in situ tests show that although the landslide was triggered by an inappropriate cutting geostructural geological engineering properties and hydrology have also played a key role in its initiation and further aggravation therefore the western and eastern boundaries of the landslide coincide with the two faults f1 and f2 in addition landslide sinisterly movement is controlled by a left lateral strike slip fault f2 it was observed that the scarp follows the n130 75 direction of bedding rocks the presence of marls and shale implies a high swelling under wet conditions thus providing lubricating sliding surfaces in addition alteration and weathering of andesite basalt tuffite and tuff have been reduced the shear strength of the slope engineering geological map egm of the landslide was prepared on the basis of aerial interpretations the orientation of ground cracks and fissures geomaterial geostructural and hydrology based on ground cracks and fissures the displacement vectors are also determined and shown on the map the relationship between the displacement vectors estimated from ground cracks and fissures with gps observation and slickness slip surface is coherent

understanding parafluvial exchange and degassing to better quantify groundwater inflows using 222rn the king river southeast australia 222rn is an important tracer for quantifying groundwater inflows to rivers especially where groundwater and surface water have similar major ion and stable isotope geochemistry uncertainties in the 222rn mass balance arise however from not accurately estimating the degree of degassing of 222rn to the atmosphere and the extent to which interaction within the parafluvial zone provides an additional source of 222rn this study estimates both 222rn production in the parafluvial zone and degassing along a 75km stretch of the king river australia in order to more precisely quantify groundwater inflows the contribution of 222rn from the parafluvial zone fp was estimated using 222rn emanation rates from near river sediments and assessment of the residence time of water in the parafluvial zone from 222rn activities and cl concentrations in water the alluvial sediments values of fp range from 40 400bq m day in the upper king to 8500bq m day in the lower king corresponding to differences in the mineralogy and the volume of the parafluvial zone the gas transfer coefficient k was estimated by matching groundwater inflows to observed increases in river discharge during a period of low discharge k decreases from 25day 1 in the upper king to 3day 1 in the lower king these k values are higher than those from most empirical formulations probably due to the extensive pool and riffle sections that promote degassing the king river is gaining in its upper and middle sections but several of the lower reaches are losing groundwater inflows on a reach scale are as high as 10m3 m day and cumulative inflows along the 75km stretch are up to 19 000m3 day groundwater inflows increase proportional to total flow reflecting the response of both groundwater and surface water systems to rainfall uncertainties in the calculated groundwater inflows are reduced by independently estimating k from the discharge data however calculated inflows are up to 40 higher if parafluvial flow were not taken into account predicted rn activities from emanation measurements agree with those measured in groundwater contribution of rn from parafluvial zone is assessed rn degassing is independently assessed by comparison with flow gauge data rn degassing is higher than predicted from empirical formulations due to pool and riffle sections king river transitions from gaining in upper sections to losing in lower sections

active transtension inside central alborz a new insight into northern iran southern caspian geodynamics the tectonic activity in the alborz mountain range northern iran is due both to the northward convergence of central iran toward eurasia and to the northwestward motion of the south caspian basin with respect to eurasia inducing a left lateral wrenching along this range these two mechanisms give rise to a nne ssw transpressional regime which is believed to have affected the entire range for the last 5 6 2 m y in this paper we show that the internal domain of central alborz is not affected by a transpressional regime but by an active transtension with a wnw ese extensional axis we show that this transten sion is young middle pleistocene it postdates an earlier n s compression and may have been initiated when the south caspian basin started moving consequently our results suggest that the south caspian basin motion may have taken place more recently than previously proposed

groundwater discharge into an estuary using spatially distributed radon time series and radium isotopes summary quantifying groundwater discharge remains a challenge due to its large temporal and spatial variability here we quantify groundwater discharge into a small estuary using radon 222rn and radium isotopes 223ra and 224ra high temporal resolution 30 min time steps radon observations at 4 time series stations were used to determine where groundwater discharge is prevalent in the estuary and to reduce mass balance model uncertainties a three endmember mixing model was developed based on short lived radium isotopes sampled at a single location to separate the shallow saline and deep fresh sources of the discharging groundwater the results show that using multiple 222rn time series stations decreased the overall uncertainty of groundwater discharge estimates from about 41 to 23 the radon derived groundwater flux was 56 13 and 35 12 cm d 1 in wet and dry conditions respectively the spatially distributed stations detected a well defined small area located four kilometers upstream from the mouth of the estuary as a groundwater discharging hotspot estimates based on a 223ra and 224ra mass balance resulted in groundwater discharge estimates of 65 18 and 84 48 cm d 1 in the wet and 18 5 and 20 6 cm d 1 in the dry the mixing model revealed contrasting results for deep vs fresh groundwater contribution in wet and dry conditions in wet conditions deep fresh groundwater discharging into the estuary contributed 65 compared to the shallow saline groundwater 35 while during dry conditions a larger contribution 80 was related to shallow groundwater a comprehensive spatial and temporal sampling strategy can produce groundwater discharge estimates with lower uncertainty and provides additional insight on where groundwater enters surface waters

conceptualization and classification of groundwater surface water hydrodynamic interactions in karst watersheds case of the karst watershed of the coulazou river southern france summary over the last two decades groundwater systems and surface water bodies are being more and more considered as a same entity which constitutes a single resource within the hydrologic system understanding groundwater surface water gw sw interactions is necessary to effectively manage the water resources concepts methods of analysis and classifications of these hydrodynamic interactions have thus been developed mostly in case of porous aquifer today gw sw interactions are still often poorly understood in many watersheds particularly in the case of complex aquifers like karst aquifers this study focuses on the influence of groundwater on the genesis and propagation of surface floods in the case of a highly karstified watershed gw sw hydrodynamic interactions are analysed i at a local scale focussing on hydrodynamic interactions between the karst aquifer in the vicinity of the river and the river and ii at a larger scale focussing on hydrodynamic interactions between a karst spring and sinkholes in the riverbed hydrodynamic time series are described using the karst watershed of the coulazou river western montpellier france as a case study results are used to adapt gw sw classifications that are usually devoted to porous media in case of the studied karst aquifer it is shown that the initial groundwater level may be used to forecast the type of hydraulic connection between the river and the saturated zone during flood however initial water level in the karst aquifer does not give any information about the flow direction gaining or losing stream during a flood the latter is found to be also controlled by the limited discharge capacity of karst conduits a conceptual model of karst river interactions during flood is given with concepts that are derived from the analysis of the coulazou watershed but that can be easily applied to most of the karst watersheds

radon tracing of groundwater discharge into an australian estuary surrounded by coastal acid sulphate soils summary widespread sulphidic deposits have accumulated in tropical coastal floodplains throughout the world sulphidic soils oxidize when floodplains are drained for urban and agricultural development as a result large amounts of sulphuric acid may be released to nearby waterways macropores may create excellent conditions for groundwater flow in coastal acid sulphate soils cass an automated radon 222rn measurement system was used to quantify groundwater inputs into a tidally dominated estuary that is known to be influenced by acid discharges from cass richmond river estuary australia a high resolution radon survey along a 120 km long segment of the tidal river identified two areas of preferential groundwater inputs intensive time series measurements in one of those areas the tuckean broadwater demonstrated that groundwater inputs are highly variable over hourly and seasonal time scales and inversely related to surface water ph elevated radon concentrations up to 12 dpm l and low ph as low as 3 3 were observed in surface waters at low tide a few weeks after a large rain event these results demonstrate that acidic waters are entering the estuary via tidally modulated groundwater flow pathways groundwater discharge rates into drains in the tuckean swamp were estimated from a dual assumption radon mass balance to be 0 09 0 16 and 0 56 0 89 m3 s 1 during the dry and wet season respectively or 6 10 and 37 59 cm day if the area is taken into account while surface runoff increased only 2 fold in the wet season relative to the dry season groundwater discharge rates increased 6 fold since groundwater can be a major driver of surface water quality radon can be useful in cass monitoring and management efforts

tracing anthropogenically driven groundwater discharge into a coastal lagoon from southern brazil summary we investigated the distribution of naturally occurring geochemical tracers 222 rn 223 ra 224 ra 226 ra ch 4 18 o and 2 h in the water column and adjacent groundwater of mangueira lagoon as proxies of groundwater discharge mangueira lagoon is a large 90 km long shallow 4 5 m deep fresh and non tidal coastal lagoon in southern brazil surrounded by extensively irrigated rice plantations and numerous irrigation canals we hypothesized that the annual intense irrigation for rice agriculture creates extreme conditions that seasonally change groundwater discharge patterns in the adjacent lagoon we further supposed that dredging of irrigation canals alters groundwater fluxes while the activities of 222 rn in shallow groundwater were 2 3 orders of magnitude higher than in surface water ch 4 and radium isotopes were only 1 order of magnitude higher therefore 222 rn appears to be the preferred groundwater tracer in this system radon concentrations and conductivities were dramatically higher near the pump house of rice irrigation canals consistent with a groundwater source modeling of radon inventories accounting for total inputs groundwater advection diffusion from sediments and decay of 226 ra and losses atmospheric evasion horizontal mixing and decay indicated that groundwater advection rates in the irrigation canals 25 cm d are over 2 orders of magnitude higher than along the shoreline 0 1 cm d nearly 75 of the total area of the canals is found in the southern half of the lagoon where groundwater inputs seem to be higher as also indicated by methane and stable isotope trends in spite of the relatively small area of the canals we estimate that they contribute nearly 70 of the total 57 000 m 3 d groundwater input into the entire mangueira lagoon we suggest that the dredging of these canals cut through aquitards which previously restricted upward advection from the underlying permeable strata the irrigation channels may therefore represent an important but previously overlooked source of nutrients and other dissolved chemicals derived from agricultural practices into the lagoon

morphological and palaeoseismological analysis along the taleghan fault central alborz iran summary the taleghan fault tf is a major active fault of the central alborz mountain range in iran located 50 km northwestwards of tehran this 80 km long fault represents one of the major structures threatening 15 million people living in the capital of iran and the surrounding cities e g karaj the tf could be the source of some of the strongest historical earthquakes recorded in the tehran region notably the 958 ad event estimated magnitude m 7 7 to characterize the kinematics and activity of the fault we carried out a detailed morphological and palaeoseismological study combining aerial photographs digital elevation models and fieldwork we show that unliked described so far the tf is not a reverse fault but a left lateral strike slip fault with a normal component its strike dip and rake within its eastern part are 105 60 and 20 40 respectively our palaeoseismological analysis shows that a sequence of 2 3 events with magnitudes mw 7 occurred during the past 5300 years if we consider a three event scenario the average recurrence interval is 2000 years and the most recent event is younger than 80 ad if we consider a two event scenario the time interval between the second and the first events ranges between 3760 and 830 years and the elapsed time since the last event ranges between 3529 and 1599 years combined with morphotectonics data our palaeoseismological analysis allows estimating a minimum horizontal slip rate of 0 6 1 6 mm yr 1 and a minimum vertical slip rate of 0 5 mm yr 1 taking the 450 m total vertical displacement observed across the fault we conclude that the kinematical change along the tf from reverse to left lateral normal occurred 1m a

the role of the lithological setting on the landslide pattern and distribution abstract in landslide susceptibility mapping studies the quality of whole inputs such as geological setting and dem derivatives should be as high as possible given the strong relationship between landslide occurrences and geology the use of a detailed lithological map is certainly an alternative preferable to the most commonly available rough geological map therefore this study focuses on this reality and proposes a procedure for improving the available geological map in a study area located 90 km north of lisbon based on a 1 50 000 scaled official geological map and according to the litho stratigraphic characteristics the map improvement was performed using the interpretation of aerial photographs by stereoscopic analysis and further field validation in order to assess the relevance of the lithological improvement regarding the relationships with landslide distribution a comparison was performed between the results obtained with the official lithological map and the improved detailed lithological map using the conditional probability cp the accountability acc and reliability rlb indexes a landslide inventory including shallow and deep seated landslides was prepared for the study area and landslides were overlapped with both lithological maps the acc and rlb indexes obtained with the detailed geological map are higher than equivalent features obtained with the official lithological map from these procedures it was possible to conclude that the detailed lithological map has a better discriminating power than the official lithological map enabling a better quality of the landslide susceptibility analysis with the separation of the relevant lithological classes

hydrogeochemical and isotopic constraints on the origins of dryland salinity murray basin victoria australia abstract combined hydrogeological and hydrogeochemical data allow flow systems and the origins of solutes in the honeysuckle creek area of the southeastern murray basin which is an area affected by dryland salinity to be constrained recharge occurs both on the uplands that are composed of fractured violet town volcanic rocks and the riverine plain that comprises sediments of the shepparton and coonambidgal formations groundwater from the violet town volcanics has low salinity 20 mmol l groundwater has intermediate cl br ratios 600 1000 which indicate that the high salinities do not simply result from halite dissolution rather mixing of groundwater homogenises cl br ratios and evaporation as a consequence of a shallow water table is the dominant process that increases salinity oxygen and h isotopes also indicate that mixing and evaporation have occurred these results indicate that land use over the whole region not just the uplands needs to be considered in any salinity management plans additionally future development of salinity is controlled by depth to the water table on the plains and the efficiency of recharge rather than by salt stores halite or brines in the unsaturated zone

assessing groundwater surface water connectivity using radon and major ions prior to coal seam gas development richmond river catchment australia abstract coal seam gas csg or coal bed methane mining is rapidly growing with poorly understood impacts on groundwater and surface water systems here we use chemical tracers to investigate groundwater surface water connectivity in an australian river system richmond river catchment new south wales prior to csg extraction but after 50 exploratory csg wells were drilled we performed four surveys of 29 interconnected creek and river sites over contrasting hydrological conditions radon was used to determine if a surface water segment was gaining groundwater radon observations over four seasons revealed that 28 out of 77 surface water segments were clearly gaining groundwater 5 were possibly gaining groundwater and 44 were undetermined this is equivalent to gaining segments in 333 km 39 of surface water from the 864 km being investigated high spatial and temporal variability in groundwater gaining segments was found na cl ratios were used to determine the fraction of groundwater in surface water overall the groundwater contribution in surface waters was 14 24 higher in post flood conditions than during the other three surveys of baseflow and moderate flow conditions the results serve as a regional baseline assessment of river water chemistry and groundwater surface water connectivity prior to the planned development of csg fields our geochemical tracer approach allows for a quick qualitative assessment of groundwater surface water connectivity in poorly gauged river systems and can define priority locations where groundwater extraction for csg mining should be carefully managed

remediation and monitoring of a highway across an active landslide at trevor north wales abstract in march 1989 a moderately steep slope forming sidelong ground below the b5434 trevor to froncysyllte road failed after a period of exceptionally heavy rainfall and severed the highway a long history of ground movements together with river erosion at the toe and a change in the groundwater regime within the slope created the preconditions for landslide site investigations characterised the ground conditions and identified the active slip surface within the compound landslide terrain the permanent remedial measures adopted proved to be of considerable practical interest involving a bored pile anchored wall with foundations socketed into a deep sandstone foundation stratum the anchored wall was designed to safeguard the highway and it was anticipated that deloading the slope would reduce the capacity for further movement the wall achieved the design objective but progressive downslope movements resumed about one year after construction they continue spasmodically to the present time with rates approaching 9 mm per year both laterally and vertically and although they affect the neighbouring areas the highway corridor remains intact the response of load cells attached to the ground anchors reveal two unusual patterns of increasing loads at the eastern end of the wall moderate load gains clearly relate to landsliding with reactivation along the existing slip surface and consequent removal of support to the wall as the ground progressively fails in a downslope direction however anomalous increases in loads recorded at the western end of the wall have proved more difficult to explain they may be due either to a build up of water pressure behind the downhill portion of the wall or to localised weak ground conditions or swelling of degraded mudstones behind the wall monitoring of the load cells will continue in order to ensure the ongoing integrity of the highway

quantifying groundwater discharge to cockburn river southeastern australia using dissolved gas tracers 222rn and sf6 groundwater discharge to the cockburn river southeast australia has been estimated from comparison of natural 222rn activities in groundwater and river water interpreted using a numerical flow model that simulates longitudinal radon activities as a function of groundwater inflow hyporheic exchange evaporation gas exchange with the atmosphere and radioactive decay an injection of sf6 into the river to estimate the gas transfer velocity assisted in constraining the model previous estimates of groundwater inflow using 222rn activities have not considered possible input of radon due to exchange between river water and water in the hyporheic zone beneath the streambed in this paper radon input due to hyporheic exchange is estimated from measurements of radon production by hyporheic zone sediments and rates of water exchange between the river and the hyporheic zone total groundwater inflow to the cockburn river is estimated to be 18500 m 3 d although failure to consider hyporheic exchange would cause overestimation of the volume of groundwater inflow by approximately 70 copyright 2006 by the american geophysical union

carbon dioxide dynamics driven by groundwater discharge in a coastal floodplain creek summary dissolved carbon dioxide co 2 may be highly enriched in groundwater however the contribution of groundwater discharge as a source of co 2 to rivers estuaries and coastal waters is poorly understood we performed high resolution measurements of radon 222 rn a natural groundwater tracer and the partial pressure of co 2 p co 2 in a highly modified tidal creek and estuary north creek richmond river new south wales australia to assess whether co 2 in surface waters was driven by groundwater discharge a spatial survey revealed increasing 222 rn activities up to 17 3 dpm l 1 and p co 2 up to 11 151 atm in the upstream direction the enrichment occurred in a drained coastal acid sulphate soil wetland upstream of a mangrove forest time series experiments 24 h were performed at two stations upstream and downstream of the p co 2 enrichment area upstream measurements demonstrated a significant correlation between p co 2 and 222 rn while downstream values resulted in a significant inverse relationship between p co 2 and dissolved oxygen apparently as a result of respiration in nearby mangroves measurements taken 2 days after a 245 mm precipitation event revealed the highest recorded 222 rn activities up to 86 1 dpm l 1 and high p co 2 up to 11 217 atm showing a strong groundwater influence after flooding these observations imply that groundwater discharge drove co 2 dynamics at the upstream station while multiple complex processes drove co 2 at the downstream station a 222 rn mass balance model demonstrated that groundwater discharge accounted for about 76 of surface water in this floodplain creek the co 2 evasion rates 799 225 mmol m 2 d 1 were driven primarily by currents rather than wind groundwater derived co 2 fluxes into the creek averaged 1622 mmol m 2 d 1 a value twice as high as atmospheric co 2 evasion and consistent with carbon uptake within the creek and downstream exports these results demonstrate that groundwater seepage was a major factor driving co 2 evasion to the atmosphere from the creek groundwater discharge should be accounted for in co 2 budgets in coastal systems

using radon as an environmental tracer for estimating groundwater flow velocities in single well tests 1 naturally occurring radon 222 was evaluated for its use in estimating groundwater flow velocities using single well tests investigations were carried out for four different well scenarios which revealed the advantages and limitations of the approach on one hand it was shown that radon is useful as an environmental tracer because of 1 the low costs of the method 2 the avoidance of any artificial tracer injection into the aquifer 3 the immediate availability of results and 4 the need for only a single monitoring well on the other hand several potential sources of error were identified including poor sampling inadequate hydraulic connection of the well because of a clogged screen and an unsuitable well diameter resulting in excessively long or short well water residence times the practical approach is supported by in depth theoretical considerations general recommendations are presented concerning the use of radon as an environmental tracer for groundwater flow assessment

constraining groundwater discharge in a large watershed integrated isotopic hydraulic and thermal data from the canadian shield or a thin veneer of coarse grained sediments natural conservative d 2 h d 18 o cl and specific conductance radioactive 222 rn and thermal tracers are integrated with streamflow measurements and a steady state advective model to delimit the discharge locations and quantify the discharge fluxes to lakes wetlands creeks and the tay river the groundwater discharge rates to most surface water body types are low indicating that the groundwater and surface water system may be largely decoupled in this watershed compared to watersheds underlain by porous media groundwater discharge is distributed across the watershed rather than localized around lineaments or high density zones of exposed brittle fractures the results improve our understanding of the rate localization and conceptualization of discharge in a large fractured rock watershed applying hydraulic isotopic or chemical hydrograph separation techniques would be difficult because the groundwater discharge signal is small compared to the background surface water inflows or volumes of the surface water bodies although this study focuses on a large watershed underlain by fractured bedrock the methodology developed is transferable to any large regulated or unregulated watershed the low groundwater discharge rates have significant implications for the ecology sustainability and management of large crystalline watersheds

climate variability in the upper jordan valley around 0 78 ma inferences from time series stable isotopes of viviparidae supported by mollusc and plant palaeoecology abstract the early middle pleistocene lacustrine sediments at gesher benot ya aqov gby in the upper jordan valley span ca 100 ka across the matuyama brunhes boundary mbb at 780 ka and oxygen isotope stages oiss 20 to 18 provide a continuous record of their sedimentary history and prevailing climate the lacustrine environment is investigated using ecological and stable isotope characteristics of gastropods belonging to the family viviparidae supplemented by other molluscan and floral indicators the sedimentary framework of the 34 m thick sequence is bounded by channel conglomerates at its base and top and consists of six sedimentary cycles each one starts with shore sediments coquina and sand and ends with deeper water sediments black mud or gray mud time series of 18o and 13c values were determined in individual shells belonging to two sympatric genera of viviparid gastropods viviparus apameae galileae and bellamya sp found in the sedimentary cycles 2 through 5 the total overall range of 18o in the time series of all the shells is from 10 5 to 5 2 vpdb and the 13c from 9 2 to 4 8 vpdb the 13c values of shells recovered from black mud are lower than those from the other sediment types suggesting a higher proportion of carbon of organic origin the 18o values show only a weak relation with sediment type the time series of the individual shells indicate a relative constancy in the water 18o and temperature whilst the variation in 13c could be related to the annual productivity cycle growth and decay of aquatic plants of the lake the 13c patterns in the time series and winter rings indicate that the rate of growth of the individual snails was ca 15 30 mm year the isotopic characteristics of the viviparid shells from these beds indicate diverse sedimentary environments and suggest that above the mbb cycles 2 5 the gby lake received constant and isotopically consistent water inflow our integrated data isotopic and ecological of molluscs and ecological of plants indicates that the geophysical magnetic phenomenon of mbb coincides with an environmental change from a relatively cold dry climate towards a warmer temperate subtropical climate in this region this change coincides with the occurrence of hominin artifacts which were found mainly in layers of the sedimentary cycles 3 5