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Data collection methodology

The majority of data sets listed in this website were identified as a result of the participation and cooperation of local and state agencies. Other national, state, and volunteer groups' data sets were identified through online research.

For the state data sources, a questionnaire was designed and standardized to ensure that all agencies contacted were asked the same questions. Information compiled included data set name and description, program's objectives, funding and sponsoring agencies, period of performance, contact information, and several metadata descriptors (laboratory and sample collection procedures, analytical methods, detection limits, and others). In addition, national and regional data sets were summarized in the same manner as state data sets.

Quality assurance and quality control (QA/QC) procedures were performed throughout the evaluation of the different data sources in an effort to identify the most reliable and complete data sets. Each data set was carefully evaluated for metadata completeness as well as internal QA/QC procedures.

National
This page contains summaries and links to the major national databases and several tools for assessing chemical data.  At the top of the page is a list of these databases and tools.  Click on an item to view its summary.  Clicking on the title above the summary will transfer you to that database's or tool's web interface. 

Regional
Chemical data are available in regional data sets.  The existing regional data sets are listed with a brief summary of information.

State
The state page allows the user to view summaries of the data sets available for each state. Clicking on a state (either on the map or using the text links below it) will bring up a brief summary of data sets available for that state, including the program name, description, chemical groups, period of performance, and contact information. A full summary of information on that data set is available by clicking on the data set name.

A link to SWAP resources for the state is also provided.  If the state's SWAP program is not available online, a link is provided to the state's environmental agency or a water quality monitoring website.

Some links allow you to download PDF files.  To read such files, you must have the Adobe Acrobat Reader.  If you do not currently have this software you may download it free of charge at www.adobe.com/products/acrobat/readstep2.html.

Search
The following fields are available to search existing records.  If you wish to view all records, you may simply click on the "submit" button without making any selections.

Geographic Extent, EPA Region, State: Choose from the drop-down lists to further limit search results.

Chemical Group:  Use the checkboxes to select as many parameters as you would like.  For more information on a chemical group, click on the group name and a window will pop up with further detail.  (Figure 1)

Figure 1. The user clicks on the chemical group Nutrients and the pop-up window opens with more information on this group.

Project Start/End Dates:  From the drop-down lists on the left of the screen, choose Before, On, or After, and enter the dates you would like to search in the field on the right.  In the example below, the user has chosen to view all records occurring before January 1, 2000. (Figure 2)

Figure 2.  User selects "Before" and enters the date to
search for records prior to January 1, 2000.

When you have completed entering information, click on the "submit" button at the bottom of the screen to begin the search, or click on the "clear" button to start again.

After clicking on the "submit" button, all results meeting the selected criteria will appear on the "Search Results" page.  The names of matching databases are displayed along with the program name.  A full summary of information is available by clicking on the database name in the first column (Figure 3).

Figure 3. Search Results Page.  Clicking on the Database Name in
the first column will bring up a detailed description of this record. 

If the initial search does not return any results, please use the back button to return to the search page.  Be sure that all keywords have been spelled correctly, and that all dates are in the mm/dd/yyyy format.  If these are correct, you may modify the additional search parameters before clicking on the "submit" button to search again.

Summaries
Select a state from the drop-down list to display a full summary of information for that state.  Select "national" to display a summary of information for all national data sets. A shortened version of the summary for each state is available on the state page (see above).

State Survey
The state survey will be accessed by the participating states providing information on their data source and data sets.  This feature can be accessed using the "State Survey" button that appears on the site home page.  Note: To reach the state survey after entering the site, click on "home" on the left navigation bar and then click "state survey."

Feedback
"Feedback" allows you to send email to the developers of the SWAP website.  From this page you can click on the email link to create a new email message using your default mail program.  Simply fill in the body of the email and send to submit your comments, questions, or suggestions about the program or this website. If you are aware of an additional data set not included on this website, please use the State Survey form to submit the information.

Caveats

Limitations and cautions for using the data sources are discussed, including disparate data formats, data duplication, data bias and data gaps, cautions of the use of the data statistically, and quality control of the data.