STORET Database Description
Data in modernized STORET (referred to from now on as STORET) is organized into five information categories:
Projects and Surveys
In STORET organizations are the primary owners of data and control access to it. Organizations own metadata (descriptions of their data). Organizations own project descriptions, and lists of organizations and people with whom they work. Organizations control a broad set of lists of their preferences or usual practices for monitoring activities. These lists may include aids to data entry (e.g. substances tracked by monitoring activities, habitat evaluation criteria, and so forth), equipment used in the field, methods used in their labs, bibliographic references, and many others. In STORET, organizations control their own data through the use of an organization-specific identification code provided by EPA, and passwords controlled locally. The identification code ties together an organization's projects, stations, and sampling data. To enter or modify an organization's data, a user must supply the proper password. Without a proper password, STORET restricts a user's access to "browse-only."
STORET allows an organization to maintain descriptions, in summary form, of the projects and surveys it conducts. The descriptions contain essential information concerning purpose, procedures, standards and methods, and quality goals. The descriptions also include information on individuals who manage and participate in the projects. Project descriptions permit linking data quality objectives and other quality control plan items to a broad spectrum of data. In this way, the needs of users for data quality descriptors can be met with a minimum of data entry effort.
Each project in STORET can involve one or more sampling stations ("sites"), and a sampling station can participate in multiple projects. Field activities and their analytical results are linked directly to all the projects they support. Projects may in turn be linked to programs, and because programs may be defined broadly to include the projects of several organizations, data from any field activity may be easily shared among both organizations and projects.
All data concerning field work is keyed to the specific location at which the field work is conducted, linking water quality measurements to the place they represent. Each STORET site has a point of reference, whose latitude and longitude are fully defined. In addition, each site may include an area boundary, a field of actual monitoring locations, and the descriptions of any permanent sampling grid or transect found there. For facilities, additional data may be entered for the individual end-of-pipe locations; for wells, a field of individual wells may be described.
Precise location definition is very important to environmental analysis, and EPA data standards for locational data are strictly followed in STORET. All applicable federal standards (FIPS, NIST, and others) are adhered to wherever possible as well.
Sites may be part of external reference schemes, and may carry a multitude of identifiers from each of these schemes. For example, a site in STORET might have an NPDES number and a state regulatory program code. Any site which contributes data to a project may be assigned a project-specific identifier.
STORET gives organizations several options for identifying their stations. Each station has a unique identifier, assigned at the discretion of the organization that "owns" the data. An organization can also assign multiple alias names to its stations. In addition, project managers can assign a unique name to each participating station that is meaningful within the context of their project. This allows a station to carry a different name in each project in which it participates. A site must first have its reference point defined before it may be assigned to one or more projects and sample collection may begin. This assures that all results are place-based. Organizations can maintain information on different types of sampling stations (e.g., well, spring, stream, ocean). The system provides a common set of geographic and descriptive information for all stations as well as information specific to the individual type of sampling station.
To assign a station to a project (i.e., to collect samples) requires a latitude/longitude coordinate [set] to be entered. STORET then takes this information -- known as the station's point of record -- and presents the user with candidate selections for the Federal Information Processing Standard (FIPS) State, County, and Hydrologic Unit Codes (HUC). STORET also allows an organization to add the latitude/longitude coordinates of a series of points to a station description, transforming the station from a single point to an area or polygon.
An organization can view and copy station descriptions belonging to another organization. Copying a station description allows an organization to include that station in its catalog of stations and makes the station available for assignment to the organization's projects.
Samples are described according to their medium and the intent for which they were collected. STORET accepts descriptions of the sample collection process which address the complete spectrum of water monitoring and sampling of the biological community. How a sample is collected is documented in STORET by links between a sample and lists of methods and equipment. Lists are available as part of the system, or client organizations may supply their own lists.
For large area samples, such as trawls, details such as the lat/long of its end points, gear deployment depth, and bottom conditions under the trawl can all be captured.
Samples can be created from other samples, by compositing, splitting, or subsampling. Each new sample is linked to its "parents" and can be traced back to all the events which might influence its results. A sample which is generated by a trawl (a "catch") might be the parent of a sample which is an individual fish. The fish in turn might be the parent of a sample which is a specimen of liver tissue, and chemical results for this liver specimen can thus be traced back to the spatial coordinates of the original trawl.
Field monitoring activities may be water, air, or sediment sample collection, biological specimen catch/trap events, or any measurements or observations obtained at the site. Each field activity is linked to those analytical results it generates (see results below).
Information gathered in the field through the process of measuring or observing the environment during the site visit is recorded in STORET as part of the site visit description. These data may include physical conditions of the site itself, status of any equipment permanently located at the site, biological habitat assessments, weather observations, and simple field-determined physical or chemical data. STORET can be used to document the frequency with which visits to sampling stations are to be conducted and to capture the results of a visit (samples collected, field measurements, and qualitative observations of conditions). Information about the sampling process, including standard procedures and methods, deviations from these methods, and sample management, may also be stored.
Station visit and sample information can be associated with a single station within a particular project.
With STORET, results obtained through analysis of samples and "in situ" measurements can be recorded and attached to the visit/sample to which they relate. The system also stores metadata concerning the quality of results related directly to the results.
Each result is linked to a field monitoring activity. If the activity was the collection of a water sample, the results are qualified by all the methods used to collect, handle, store, and process that sample. The results may be further qualified by the identity of the lab performing the analytical work, and equipment and methods used in this process. STORET captures information about the participating laboratories and their qualifications. It also captures identifying information for the substances or properties being measured with qualifiers that enable valid data comparisons to be made. Statistical information concerning confidence intervals may be supplied, and for results which are not quantified, detection status and quantitation status may be stored. Results which are counts or percentages may be qualified by the range of some size or weight variable which they represent.
Biological results are handled in different ways. For a "catch", biota may be grouped and regrouped repeatedly for counting, weighing, or measuring. For example, one grouping might be by taxon, and the counts recorded for purposes of computing taxonomic diversity and richness, while another grouping might be a user-defined histogram or class frequency table of fish lengths within a species, and yet another might be to record counts and weights of only adults, or only gravid females, or any other category the analyst might request. A catch might be divided so that a group contains only 1 individual, and a detailed description of it recorded.