Water and Air Monitoring and Reporting

Online User Guide: Environmental Monitoring System Web Reporting (EMS WR)

3.4 Creating Graphs

EMS WR allows you to create two types of graphs:

These graphs are particularly useful when you want a quick visual interpretation of sample data from a single monitoring location.

3.4.1 Trend Graph

[TREND GRAPH CURRENTLY DISABLED]

The Trend Graph allows you to see how the level of a single parameter has changed over time at a single monitoring location. You can choose to graph all historical samples in EMS for a parameter, or you can specify the time period you want to graph.

EMS WR automatically inserts the Canadian Drinking Water Guideline (CDWG) limit for the selected parameter into the graph as a red horizontal line. This enables you to quickly assess the parameter's trend over time and against the CDWG limit.

Business Needs

All EMS WR users can benefit from creating trend graphs. For example, a health authority might want to know when during the year fecal coliform bacteria levels are highest at a certain water source. Or, water purveyors might want to graph nitrate-nitrogen concentrations to find out if there is any trend. Similarly, ministry staff will often find this graph useful for their business needs.

Business Needs Hint: if you are an advanced user, you can work with the Data Results tool to create more complex graphs. For example, you can use Data Results to download results for turbidity and fecal coliform over a certain time at a monitoring location. Then you can use a spreadsheet in Excel, or a graphing package like Golden Software's Grapher to plot and analyse the results.

Business Needs Hint: you have the option to show the y, or vertical axis as a logarithmic scale (as opposed to a linear scale). This is particularly useful when values range over several orders of magnitude. For example, if you are plotting bacterial levels over time, you might want to use a logarithmic scale since bacteria counts can range exponentially.

Basic Procedure

To create a trend graph:

1. From the Main Menu, click on the Trend Graph image under the Graphs heading.

2. Enter the EMS ID number for the location to be graphed.

Business Needs Hint: in general, you should have the EMS ID before using the Trend Graph tool. If you do not have the ID, search for it using the Monitoring Locations tool. Alternatively, you can click on multi section symbol (...) beside EMS ID on the Trend Graph - Criteria page. However, this search tool has fewer search options than Monitoring Locations.

3. Select a scale for the y-axis:

4. Choose the parameter you want to graph by clicking on the Parameter For Graphing drop-down list and selecting from the list.

5. Select a time period to graph.

Default is the entire history for the selected parameter.

To graph specific time period, select the Show The Selected Parameter For A Specific Date Range radio button and type in a From and To date range (YYYY/MM/DD format).

6. Click the Graph button on the lower right-hand corner of the page (you might have to scroll down to do this).

3.4.2 Exceedance Graph

An exceedance graph enables you to determine, at a glance, whether the results of a water sample from a single monitoring location complies with the Canadian Drinking Water Guideline (CDWG).

Business Needs

Water purveyors and health authorities in particular will find this tool useful for quickly assessing the quality of sample results.

Note: the Exceedance Graph tool should only be used to assess drinking water samples.

Example Graph

These exceedance graphs show sodium and lead totals for a sample, and compare them to CDWG limits:

Parameter results within CDWG limits appear on the left as a blue square symbol (labeled with the actual result), and parameter results exceeding these limits appear on the right as a red square symbol (labeled with the actual result). Parameter results exactly at the CDWG limit appear in the middle as a blue square symbol. For this graph, the sodium total is within the CDWG limit, while the lead total exceeds the limit. The CDWG limit for each parameter is shown in the middle of the graph. Parameters that do not currently have a CDWG limit are not plotted.

The exceedance graph for pH is slightly different from the graphs of other parameter results. Rather than having a CDWG limit, it displays an acceptable pH range (i.e. 6.5 to 8.5 pH units):

Basic Procedure

To create an exceedance graph:

1. From the Main Menu, click on the Exceedance Graph image under the Graphs heading.

2. Enter the EMS ID number for the location to be graphed.

3. To graph a date other than the most recent sample, click the radio button to the left of Select a Specific Sample Date and type in a date in the YYYY/MM/DD format.

4. If you want to eliminate parameters, click on their checkmarks or click on Toggle section checks above each category heading.

5. Click the graph button on the lower right-hand corner of the page (you might have to scroll down to do this).

Finding specific sample dates

Water purveyors and health authorities might only want to graph the most recent sample results. For example, a water purveyor might simply use the Exceedance Graph each month to determine whether its sample is within the limits of the Canadian Drinking Water Guideline.

If a specific date is required and the water purveyor or health authority cannot provide this date from logs or records, it is possible to search EMS WR for sample dates within a date range. To do this:

1. From the Main Menu, click on the Data Results button.

2. Type the EMS ID number into the first field.

3. Type the date range you want to search into the Start Date/Time To and From fields.

4. Click the retrieve button on the lower right-hand side of the page. You might need to scroll down to do this.

Tip: you can narrow your search by filling in other fields. For more information on fields on the Data Results page, see EMS WR Screen-by-Screen Reference.

6. In the field at the bottom of the screen, type a name for the information retrieval (e.g. jsmith sample date) and click the OK button.

7. Click on the Download Data button.

8. Select the radio button next to the Retrieval Name created in step 6.

9. Click the OK button to download the file to your computer.

10. Click Save.

11. Navigate to the location where you want to save the file, type in a file name, and click Save.

12. Use Microsoft Excel, Access, or another spreadsheet program to open the document.

13. Ensure that the EMS ID and location are correct, and use the Collect Start Date column to find specific sample dates.

14. Make note of the date(s) you want to graph and return to the Exceedance Graph tool.

15. See step 3 under Basic Procedure to continue.

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