General Database for Ground Water Site Information

Transcription

1 General Database for Groun Water Site Information by Jean-Raynal e Dreuzy 1, Jacques Boin 3,HervéLe Gran 4, Philippe Davy 2, Damien Boulanger 4, Annick Battais 2,OlivierBour 2, Philippe Gouze 5, an Gilles Porel 3 Abstract In most cases, analysis an moeling of flow an transport ynamics in groun water systems require longterm, high-quality, an multisource ata sets. This paper iscusses the structure of a multisite atabase (the H1 atabase) evelope within the scope of the ERO program (French Environmental Research Observatory, The atabase provies an interface between fiel experimentalists an moelers, which can be use on a aily basis. The atabase structure enables the storage of a large number of ata an ata types collecte from a given site or multiple-site network. The atabase is well suite to the integration, backup, an retrieval of ata for flow an transport moeling in heterogeneous aquifers. It relies on the efinition of stanars an uses a template structure, such that any type of geolocalize ata obtaine from wells, hyrological stations, an meteorological stations can be hanle. New types of platforms other than wells, hyrological stations, an meteorological stations, an new types of experiments an/or parameters coul easily be ae without moifying the atabase structure. Thus, we propose that the atabase structure coul be use as a template for esigning atabases for complex sites. An example application is the H1 atabase, which gathers ata collecte from a network of hyrogeological sites associate with the French Environmental Research Observatory. Introuction For the past 20 years, many groun water atabases have been evelope (see, e.g., Barazzuoli et al. 1999; Newell et al. 1990; Seyfrie et al. 2001; van er Lee an Lomenech 2004). One of the main objectives of atabases is to promote long-term monitoring an backup of groun water ata, which is a basic requirement for many hyrogeological stuies. Despite the broa range of available atabases, few are suitable for moeling purposes at the fiel scale, i.e., for stuies eicate to aquifer an/or 1 Corresponing author: Géosciences Rennes (UMR CNRS 4661) Campus e Beaulieu, Université e Rennes 1, Rennes Céex, France; jean-raynal.e-reuzy@univ-rennes1.fr 2 Géosciences Rennes (UMR CNRS 4661) Campus e Beaulieu, Université e Rennes 1, Rennes Céex, France. 3 Hyrasa (UMR CNRS 6532) Université e Poitiers, 40, Avenue u Recteur Pineau, Poitiers Céex, France. 4 Méias France, BPi , Avenue Eouar Belin, Toulouse Ceex 9, France. 5 UMR 5568, Laboratoire e Tectonophysique, ISTEEM. CNRS Université e Montpellier 2. Montpellier, France. Receive November 2005, accepte February Copyright ª 2006 The Author(s) Journal compilation ª 2006 National Groun Water Association. oi: /j x process characterization. In hyrogeology, there is a real nee to evelop atabases that gather together a large number of ifferent types of ata collecte at specific geographical sites. Site-oriente groun water atabases are the natural interface between long-term recoring an experiments on the one han an moels on the other han. This paper iscusses the structure of a multisite atabase (the H1 atabase) that has been evelope within the scope of the ERO program (French Environmental Research Observatory, The so-calle H1 observatory is a national network of hyrogeological sites in France. Toay, H1 comprises three hyrogeological sites (Ploemeur, Poitiers, Caarache), which are complementary in terms of geology, aquifer exploitation, an scientific research objectives. The goal of H1 is both to improve the unerstaning of the water cycle an transport of chemical species in heterogeneous aquifers, an to provie high-quality (well ocumente) ata for testing preictive moels an for eveloping groun water moeling tools. The latter goal makes the evelopment of a atabase one of the crucial tasks of the H1 observatory. Of course, because the H1 atabase relates to hyrogeological sites, the main ata source is boreholes. Borehole ata can be subivie Vol. 44, No. 5 GROUND WATER September October 2006 (pages ) 743

2 into well escription (e.g., precise location an altitue, rilling report, tubing escription, geological log, core, an/or cutting photographs), hyraulic ata (e.g., potentiometric levels, pumping test reports, flowmeter logs), chemical ata (e.g., groun water sampling an analyses, in situ hyrochemical monitoring, tracing experiments), an geophysical ata (e.g., natural gamma, flui resistivity, acoustic images). Other site information inclues topology, soil type, geology, surface geophysical ata, an meteorological ata. Further etails about the contents of the H1 atabase are available on the H1 observatory Web site: The evelopment of the H1 atabase was accomplishe in two phases. In the first phase, point ata, i.e., ata acquire from a platform ientifie by the coorinates of its surface outcrop, were assemble. The platform can be a well, a meteorological or a hyrological station. All oneimensional ata acquire within a well were inclue. The structure of the atabase is the focus of this paper, specifically the subsurface platform atabase. The secon phase, which constitutes the assembly of surface ata incluing topology, soil type, geology, an surface geophysical ata, is iscusse in php3?i_article¼24. Database Structure The atabase structure requires a single occurrence an full characterization of each piece of ata, with a precise escription of the relations among ata. The atabase was evelope to comply with the general principles of atabase structure as efine by the theory of normalization (Fagin 1981). This normalize esign enhances ata integrity by minimizing reunancy, thus preventing upate anomalies an ata inconsistencies. For escription purposes, we have use the Enhance Entity Relationship conceptual moel (Chen 1976; Co 1970; Teorey et al. 1986). In the graphical representation of the atabase structure (Figure 1), each box represents an entity. An entity, or component, is the representation of an element having a role in the system. Entities are interrelate. The atabase is mae up of five main components, i.e., site, platform, sequence, measure, an experiment (Figure 1). Two aitional boxes station an well are linke to the platform box, an three other boxes value, parameter, an file are linke to the measure box. We will first escribe the five main components an subsequently the relations among them. The Five Main Components Site The site component contains the site s name an ientification number as well as a file giving a escription of the site incluing, for example, the objectives of the site stuies. The site ientification will be extensively use as all ata will be boun to a particular site. Linking ata to an explicitly efine site has the avantage of storing several atabases in the same repository. Platform: Well, Meteorological an Hyrological Stations As use herein, the general term platform refers to a well, a meteorological station, or a hyrological station. All platforms are referre to by their ientifier an have a given position (latitue, longitue, an altitue). Define by precise latitue an longitue values, the position of the platform is intrinsically fixe. Hyrological an meteorological stations are unique platforms as long as they Figure 1. Simplifie ata conceptual moel (DCM) of the atabase. Contents an relations among the main atabase components are shown. The full DCM of the H1 atabase is available on the H1 observatory Web site php3?i_rubrique= J.-R. e Dreuzy et al. GROUND WATER 44, no. 5:

3 remain at the same position. When move, they become new stations. Horizontal isplacements of a platform that may be ue to tectonics are neglecte for two reasons. First, these isplacements are very small with respect to the istances of interest in most groun water stuies. Secon, most hyrogeological moels use interplatform istances, which are not affecte by such isplacements. Changes in altitue are more likely. Thus, the altitue of a platform is efine by a series of time-reference altitue ata (escribe subsequently uner Altitue an Depth Definition), which has to be upate when new measurements are available. Platforms belong to a unique site an can even belong to a site s subsite (fiel subsite of a platform). In fact, ifferent groups of piezometers are commonly use for ifferent sets of experiments. As parts of a subsite, the ata collecte from these groups of piezometers will be easily retrieve. Depening on its type (meteorological station, hyrological station, well), a platform inherits specific characteristics. For hyrological stations, an inherite characteristic is the spring or river on which the station was place. For wells, the specific characteristics are the beginning an ening ates of rilling operations, the name of the rilling company, the rilling report, an photos of the well. The altitue recore in the platform component correspons to the altitue of the wellhea just after well installation. The well component is linke to the four components core, geological log, technical cross section, an aquifer, each having a complex structure reflecting the fact that wells are key an well-ocumente hyrogeological objects. The core component is esigne to store information about the core or cuttings extracte from the well. The core component is completely escribe by its nature (core or cutting), its origin (given by the link to well), an its storage location. We will see in the escription of the sequence component that the core component is also relate to the samples that can be collecte from the core, so that all elements of the core can be easily locate. The geological log component contains, as a function of epth, the geological characteristics of the well: lithology an stratigraphic ages of rock units, an possible heterogeneities such as foliation, schistosity, being planes, fractures, faults, or karst features such as channels. The ip an strike of heterogeneities may be specifie if known. The type of ata use for the geological interpretation must also be specifie (core/cuttings examination, borehole imaging, etc.). Uniform lithology in a given epth interval can be represente by the repetition of the same lithologic name for several consecutive epths. The technical cross section component contains, as a function of epth, the ate an time of rilling, the rilling metho (e.g., percussion, air rotary, mu rotary, core rilling), the rilling iameter, an spee. If the well is case, etails are given about the casing iameter an material (e.g., steel, stainless steel, soli or screene polyvinyl chlorie [PVC]). Up to three concentric casings may be escribe at a given epth. If the annular space between the hole an the casing has been seale, the grout material use must be specifie. If a well is totally or partially uncase, collapse well intervals must be inicate. All these ata may be avantageously synthesize by a technical rawing (store in a jpeg file, for example). The well belongs to a unique aquifer, the one in which it is screene or penetrate as an open borehole. In France, by law a well cannot intercept more than one aquifer in orer to prevent contamination between aquifers. A well linke to several aquifers coul be introuce into the atabase as several wells having the same coorinates but belonging to ifferent aquifers. The measure component stores measurements collecte at the same place (location an epth or altitue), on the same ate with the same metho. Most measure components contain a single measurement, for example, the potentiometric level at one piezometer at a efinite time. A water level measure by two ifferent tools (e.g., pressure sensor, manual probe) will be store in two ifferent measure components. Another measure component mae up of a single element is permeability. However, when permeability is erive at a given point by ifferent analyses, such as a well test an a Darcy experiment on the core, the ifferent values shoul be store separately. Examples of measure components mae up of several measurements are chemical analyses. ICP-MS analyses give simultaneously the concentrations of several chemical species that are obtaine on the same ate an at the same location using the same analysis metho. An ambiguous case is that of meteorological measurements, which always refer to several measuring probes. For ata sets elivere by a certifie agency, the measurements will be store in the same measure component owing to the high confience level of ata. In other cases (e.g., on-site weather station ata), the measurements will be store in several measure components, each of which reference one of the probes. In the measure component are store the ate an epth or altitue of the measurement as well as the measuring metho. The location of the measurement is efine by a compulsory link to the platform through the sequence escribe subsequently. The measurement is linke to a measurement property component esigne to store etails about the measurement context such as the position of packers (if some have been use) or the etails of chemical analyses. The measure component is the root of two information trees about the value(s) of the measure an their origin: Each measure component is linke to one or several values given by a number, its precision (value component), an a compulsory link to the parameter measure (e.g. chlorie concentration, water level). The parameter itself is characterize by a unit an a category taken from the unit an category metaata lists. We have restricte ata iversity by allowing ata that characterize a site (e.g., geophysical an chemical ata) to be store in a similar way. These are ata about the ata an are typically calle metaata. Units an parameters become metaata. In this way, the ata structure can be simplifie, a large J.-R. e Dreuzy et al. GROUND WATER 44, no. 5:

4 range of ifferent ata can be store in the same template, an other types of ata can be ae to the atabase without any moification of its structure. In orer to ensure that ata are traceable, each measurement comes from a file store in the atabase. The file is characterize by its name, URL, type, an topic, an is linke to the people who supplie, integrate, an contribute to the measurement. Each of these people belongs to a referre agency, which is itself completely efine in the agency component. This efinition of the measurement ensures a high level of generality that allows the storage of very ifferent ata acquire on platforms. Sequence The sequence component contains a set of measurements that shoul be strongly linke together or that coul overlap if store in the same measure component. In most cases, the sequence will be empty. The few cases of nonempty sequences are as follows. Geophysical log. Data collecte in the same logging phase shoul be linke together in orer to be easily reconstructe. Core sample on which petrophysical measurements are performe. The same sample can be analyze by several people an laboratories using several methos on ifferent ates. Each analysis result is a measurement. Flui sample on which chemical analyses are performe by ifferent measuring methos (e.g., Inuctive Couplage Plasma Mass Spectrometry (ICPMS), spectrometry). The sequence has also been efine for file management purposes (as use herein, the term file refers to the file from which the ata are loae into the atabase). In fact, all measurements of the measure component come from the same file. A unique file is linke to the measure component. If several chemical analyses are mae on the same flui sample, for example, they will be store in ifferent files an thus in ifferent measure components. The sequence is ae to keep a link between these measure components. The sequence component is efine by its nature (geophysical log, core, or flui sample), its epth interval coverage, the sampling ate (use especially when sampling a core), an the sequence metho an tool (which give etails on core sampling). Experiments An experiment is escribe by several features such as its nature, its beginning an ening ates, an the name of the team involve. First, the experiment component escribes the experiment carrie out at a site. Secon, it gives a simple access to a particular type of experiment performe at one or several sites. Thir, the link between the experiment an the measurements collecte specifically within the experimental framework allows an easy retrieval of the experimental conitions an results. Note that the use of packers is itself consiere an experiment because the natural or force flow in the aquifer may be moifie by the isolation of a given well portion an/or the sealing of fractures. The beginning an ening ates of the experiment correspon to the packer installation an removal. The atum of interest (recore in the atabase) is the precise location of the packer in the well. All ata collecte uring the experiment, even the ata collecte continuously without any particular link to the experience, can be retrieve with a simple test on the ate of the experiment. If necessary, more ata concerning the conition before the experiments may also be tracke on a ate basis. It is especially important for well tests an tracer tests. Relations among Components Relations among atabase components (Figure 1) are efine by carinalities picture as branches (Figure 2). For example, consier the measure an value components in Figure 1. Each value is linke to exactly one measure, an, in the other irection, one or several values can be linke to one measure. All values linke to the same measure thus share the same measurement properties; they were performe on the same ate, at the same place, with the same metho, an on the same sample, when a sample is involve. The relations among the main components are as follows. A site is mae up of a set of platforms an experiments. On the other irection, each platform or experiment belongs to one site. As a result, several sites can use the same atabase so that the atabase aministration investment can be share. A platform inherits either from a well or from a meteorological/hyrological station. A measurement necessarily belongs to one platform an may be linke to one experiment. The sequence component, situate between the measure an the platform components, is use only for storing ata collecte from cores or cuttings, geophysical logs, an water samples (for chemistry). Each experiment is irectly linke to the measurements performe within its framework. Altitue an Depth Definition Several epth an altitue measurement conventions are possible. A geographical atum is always specifie, Figure 2. Branch symbol conventions of the Data Conceptual Moel shown in Figure 1. Component 1 is relate to (a) exactly one component 2, (b) one to several components 2, (c) zero to several components 2, an () 2 inherits from 1. Inheritance means that 2 has both its own properties an the properties of 1 (Teorey et al. 1986). Inheritance is use in the atabase for platforms that inherit either from the well or from the meteorological or hyrological station properties. 746 J.-R. e Dreuzy et al. GROUND WATER 44, no. 5:

5 an a particular epth or altitue may be reference to the geographical atum, the altitue of the wellhea, the altitue of the groun next to the well, the altitue of the tubing hea, or anything else such as the summit of a tripo place straight above the well. The reference epens on the measuring tool an the time of the measurement. For these reasons, a epth or altitue reference is assigne to each epth or altitue recor. The epth or altitue is efine by three fiels, which are the reference point chosen as the epth origin (e.g., the hea of the well, the groun, or the geographical atum), the altitue z r of the reference point taken from the geographical atum, an the epth (>0) or altitue (<0) of the measurement (in meters) from the reference point z m, where z m is the curvilinear istance between the reference point an the measurement point along the well an allows for curvature of the well. The sign convention is a positive epth point below the reference point inasmuch as more ata are locate below the reference point than above. Whatever the reference point use for the epth origin, the geographical altitue z can always be calculate from z ¼ z m 2 z r. Metaata Lists The metaata lists (Table 1) are a key element of the atabase as they guarantee the use of the same ientifier for all occurrences of the parameter, experiment type, etc. The corresponing fiels of the atabase must be fille with the metaata of these lists. For example, lithologies are taken from the lithology metaata list. New fiels can be ae to the metaata lists, provie that a similar ientifier has not alreay been recore. To ensure the metaata ientifier uniqueness, requests for aitions are sent to the atabase aministrator who seeks the avice of the atabase manager. Site names are also taken as metaata (last entry in Table 1) to guarantee the correct naming of sites in the atabase. Interface to the Groun Water Database Four ifferent roles have been efine in the atabase interface. The ata supplier transforms the raw ata into the require format an uploas the ata to an FTP server. The supplier may run a valiation tool that checks the number of columns in the file an the consistency of the values (e.g., a chemical concentration cannot be negative). The site valiator receives notifications when new files have been uploae, checks the consistency of ata, an valiates them accoring to the general knowlege of a given site. This operation consists of thoroughly examining uploae ata, verifying ata consistency, an making sure that appropriate corrections have been mae to rough ata (e.g., sensor rift correction, removal of aberrant points). At the present time, the atabase oes not contain any etail about the scientific valiation process. An upgraing of the measure component is planne to store etaile information on checks an corrections applie to each ata set. The valiator may insert the ata with a flag inicating that these ata have not been valiate. There is one valiator per site, who is consiere the site manager. The valiator s expertise improves the quality of the ata. The valiator also may remove ata from the atabase by specifying the file to which the ata have been move. The atabase aministrator manages the technical issues of the atabase an guarantees the sustainability of the atabase. The aministrator implements the backup proceures an upates the metaata lists. The aministrator also manages the atabase user access accoring to the three roles assigne: ata supplier, site valiator, an en user. Table 1 Metaata lists incluing name, example of content, an the main component in which they are use List Name Example of Content Use in Aquifers Miocene limestone, Pleistocene sany clay, Dogger, lower an mile Lias Well Lithology Anorthosite, clay, olomite, gabbros, gneiss Log Tubing material Steel, concrete, screen, cemente, collapse, uncase, PVC, Teflon Ò Well Core nature Core, cutting, none Well Experiment type Well test, slug test, flowmeter test, tracer test, geophysical test Experiment Parameter categories Normal electrical resistivity, spectral gamma raioactivity, neutron porosity, acoustic velocity, rainfall, barometric pressure, temperature, concentration, ispersion, porosity, hyroynamic parameter, hyrogeochemistry Parameters Pressure, temperature, flui conuctivity, formation resistivity, ph, epth, turbiity, salinity, natural gamma raioactivity, hyraulic conuctivity, effective porosity, aqueous concentration Measuring tool type Borehole geophysics probe, pump, submerge pressure sensor, heat-pulse flowmeter, multiparameter probe, weather station, issolve oxygen/temperature probe, water sampler Measuring tool Acoustic televiewer, Meteorological_Station_SEH_Poitiers, hyrogeochemical_multiparameter Structures Stratification, fault, lineament, ike, groove, slump Log Symbol (unit) P (Bar), T ( C), Eh (mv), z (m), Q (m 3 /s), K (m/s) Sites Caarache, Ploemeur, SEH Poitiers Site J.-R. e Dreuzy et al. GROUND WATER 44, no. 5:

6 The en user queries the atabase with web browsing request tools. The atabase may be consulte by users registere by the aministrator. To create an account, the user must give his/her name, company s name, an aress. He must also accept the general terms an conitions of ata access an use, which are etaile on the Web site. Among these conitions, rules are given for the citation of the organization an/or people who have acquire the ata. Rather than efining multiple levels of accessibility accoring to the egree of ata confientiality, only fully open ata are integrate into the atabase. Nevertheless, two levels of accessibility have been efine accoring to the ata valiation status. Members of the research project can access the entire atabase (all ata of all sites), whereas other users (calle anonymous users in the atabase) may access only those ata that have been scientifically valiate. Note that there is no waiting perio for ata accessibility, i.e., ata are available as soon as they have been valiate. Data extraction is one from the web interface. Queries consist of three components relating to the parameters measure, the experiment performe, an the time range an location area. Concerning the parameter component, requests can be mae for one to several parameters (e.g., transmissivity, ispersion coefficient) or experiment types (e.g., hyraulic test, tracer experiment). Concerning the time an location component, requests can be mae for a given time range an on a site, on a subsite, on multiple sites, or on a geographical area. Concerning the experiment component, requests can be mae for an experiment type or on a well-ientifie experiment. If one of these components is not specifie in the request, it is isregare by the request. For example, if no location is specifie, all ata will be searche regarless of location. As the objective of the atabase is ata organization an stanarization, as yet no visualization tool has been linke to the atabase. Conclusions In hyrogeology, as in many other isciplines, a large number of ata collecte by fiel experimentalists coul be better use if ata were mae available to the scientific community through atabases. In this paper, we propose a site-oriente groun water atabase, esigne to provie an interface between fiel experimentalists an moelers that can be use on a aily basis. The structure of the H1 atabase is esigne to manage a broa range of information that incorporates both routine monitoring of point locations an experimentally erive ata from several site locations. We propose that the H1 atabase structure coul serve as a template for esigning future atabases for complex sites. Like any other archiving system, the propose atabase structure has its own limitations. The main problem relates to nonpoint ata such as storage coefficient or ispersivity. Since each measurement necessarily belongs to one platform, the atabase is not well aapte to parameters that are interprete from experiments involving two or more wells. However, these parameters may be easily hanle by aopting a convention. We propose that each parameter coul be linke to the main platform involve in the measurement (e.g., pumping well for storage coefficient, injection well for ispersivity). The other platforms involve in the measurement coul be mentione in the interpretation report store in the atabase an linke to the ata. Acknowlegments This work was fune by the ERO program of the French Environmental Research Observatory. The authors woul like to thank Philippe Renar, William Alley, an an anonymous reviewer for their constructive comments. Eitor s Note: The use of bran names in peer-reviewe papers is for ientification purposes only an oes not constitute enorsement by the authors, their employers, or the National Groun Water Association. References Barazzuoli, P., M. Bouzelboujen, S. Cucini, L. Kiraly, P. Menicori, an M. Salleolini Olocenic alluvial aquifer of the River Cornia coastal plain (southern Tuscany, Italy): Database esign for grounwater management. Environmental Geology 39, no. 2: Chen, P.P.-S The entity-relationship moel Towar a unifie view of ata. ACM Transactions on Database Systems (TODS) 1, no. 1: Co, E.F A relational moel of ata for large share ata banks. Communications of the ACM 26, no. 1: Fagin, R A normal form for relational atabases that is base on omains an keys. ACM Trans. Database Syst. 6, no. 3: Newell, C.J., L.P. Hopkins, an P.B. Beient A hyrogeologic atabase for grounwater moeling. Groun Water 28, no. 5: Seyfrie, M.S., M.D. Murock, C.L. Hanson, G.N. Flerchinger, an S. Van Vactor Long-term soil water content atabase, Reynols Creek Experimental Watershe, Iaho, Unite States. Water Resources Research 37, no. 11: Teorey, T.J., D. Yang, an J.P. Fry A logical esign methoology for relational atabases using the extene entity relationship moel. ACM Computing Surveys (CSUR) 18, no. 2: van er Lee, J., an C. Lomenech Towars a common thermoynamic atabase for speciation moels. Raiochimica Acta 92, no. 9 11: J.-R. e Dreuzy et al. GROUND WATER 44, no. 5: