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Upper Midwest Environmental Sciences Center

folder.gif Long Term Resource Monitoring Program
  Water Quality Data - Graphical Water Quality Database Browser

Graphical Water Quality Database Browser Help Page - Stratified Random Sampling

Note: a separate graphical browser is available for LTRMP fixed site sampling data.

Help Topics

For more information on the Long Term Resource Monitoring Program (LTRMP) Water Quality Component monitoring procedure: LTRMP Procedures: Water Quality Monitoring

Help Using Graphical Water Quality Database Browser

About the Graphical Water Quality Database Browser

The graphing software used for the Graphical Water Quality Database Browser was written using Java Applet technologies. To work on your computer, your Web browser must have java enabled. The graphing software displays a number of graphs to compare seasons, reaches, or strata at the same time. The user then can choose one of the graphs to be displayed in more detail in the main window. The details are in the form of a box plot and a table containing the values in the box plot. Although LTRMP will take bottom and mid-depth samples at some sites for some parameters, all values reported in this browser are for surface samples.

Using the Graphical Water Quality Database Browser

Picture of Graphing Display

Above is a display of output from the graphing tool. The display is divided into two regions, the left column and the main window. In the left column, small graphs (one for each season, reach, or stratum) are displayed. The main window displays the active graph and its associated data table. To change the active graph, point the mouse arrow at the smaller version of the graph in the left column. This will highlight the chosen graph, displaying it in the main window. To see a numerical value on the graph in the main window, use the mouse to point to the location on the graph that you want to see the value for, or point to a specific year or value in the table.

Enabling Java in Netscape and Internet Explorer

Internet Explorer

    1. Click "Tools"
    2. Click "Internet Options"
    3. Click "Advanced"
    4. Check the check boxes under the Java category

Netscape Navigator

    1. Click "Edit"
    2. Click "Preferences"
    3. Click the "Advanced" option
    4. Click the "Enable Java" option

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Help With Seasons

LTRMP conducts stratified random sampling of water quality over periods during spring, summer, fall and winter as described in the following table:

Table. Calendar used for stratified random sampling in the Long Term Resource Monitoring Program. The primary sampling period begins on a Monday and extends over the next 14 days exclusive of weekends. A third week may be used if necessitated by urgent circumstances, safety considerations, or equipment failure. The SRS sampling schedule takes second priority if it conflicts with fixed-site sampling.

Sampling period
Start date
Spring Monday of last full work week in April Period of maximum discharge in the Upper Mississippi River
Summer Monday of last full work week in July Late summer conditions, typically low-flow period of maximal water temperature, minimal oxygen

Fall Monday of second full work week in October Low-flow period after aquatic vegetation die-back and before ice formation. Period of maximum waterfowl migration. Moved forward a week in 1996 and 1997 to avoid conflict with waterfowl hunters.

Winter Monday of last full work week in January Period of maximal ice and snow cover, lowest water temperatures, and minimal oxygen concentration.

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Help With Reaches

All LTRMP study reaches (Pool 4, Pool 8, Pool 13, Pool 26 and an Open River reach on the Upper Mississippi River, and the La Grange Pool on the Illinois River) are sampled for water quality. A more detailed description of these study reaches can be found at: Study Reaches. It should be noted that each reach is sampled within strata, and we provide graphical summaries only for strata and not the reach as a whole.

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Help With Strata

The LTRMP stratifies water quality sampling across five strata, characterized by enduring geomorphic and physical features(Wilcox 1993). The LTRMP water quality sampling strata are defined as follows:

Main Channel

Aquatic areas of the main navigation channel and adjacent channel borders extending to the nearest shoreline.

Side Channel

This stratum includes both secondary and tertiary channels. These channels may or may not have terrestrial margins, but have measurable current velocities at normal water elevations. This differs from the LTRMP fish sampling stratum definition, as fully submerged secondary or tertiary channels that do not have terrestrial margins (such as may occur in impounded areas above dams) are not considered side channels for fish sampling.

Backwater Contiguous

Backwater contiguous is characterized by having some connection by water to the main navigation channel, but are separated from the main channel by a terrestrial area and carry little flow at normal river elevations. Backwaters may consist of floodplain depression lakes, sloughs, lateral levee lakes, bays, and artificial lacustrine areas.


Impounded areas are large, mostly open-water areas located immediately upriver from locks and dams. Water elevations are held higher than pre-impoundment levels by the dams. Impounded areas may contain many areas that were terrestrial before impoundment.


There are two large lakes that are sampled as separate strata. In Pool 4, Lake Pepin is a deep lake formed by the delta of the Chippewa River. In Pool 26, Swan Lake is a highly managed shallow lake connected to the Illinois River near the Mississippi River.

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Help With Water Quality Variables

The LTRMP currently samples, or has sampled in the past, many water quality characteristics. The browser only graphs 14 selected variables that are typically of most interest to users. A more detailed description of the variables can be found in the LTRMP Procedures Manual.


Water temperature for the sample measured in degrees Celsius.

Dissolved Oxygen

Amount of Dissolved Oxygen in the sample. Measured in milligrams/liter.


Conductivity (ability of the water to conduct an electric current) measurement for the sample. Measured to the nearest uS/cm.


pH measurement for the sample. Measured in pH units.


Turbidity (water clarity) measurement for the sample. Measured in nephelometric turbidity to the nearest whole nephelometric techniques.

Suspended Solids

The total particulate material trapped by a glass fiber filter and dried at 105 degrees Centigrade. Reported as milligrams per liter.

Volatile Suspended Solids

The weight loss on combustion at 500 - 500 degrees Centigrade of the total suspended solids residue for the sample. Reported in milligrams per liter.


Calibrated fluorometric chlorophyll. Values calibrated using specific calibration factors from the concentration of photosynthetic pigment chlorophyll-a, corrected for phaeophytin as determined by the spectrophotometric technique using 90% acetone extraction. Approximate calibration equation is: Chlorophyll a = 1.9 + 0.9####FL1. Units of Chlorophyll and FL1 are both micrograms per liter.

Total Nitrogen

The total nitrogen concentration (dissolved and particulate) in the sample. Reported as milligrams of nitrogen per liter.

Nitrate Nitrite

The total amount of nitrate plus nitrite for the sample. Measured in milligrams of nitrogen per liter.

Total Phosphorus

The total amount of phosphorus (dissolved and particulate) in the sample determined using persulfate digestion. Reported as milligrams of phosphorus per liter.

Soluble Reactive Phosphorus

Soluble reactive phosphorus measurement for the sample. Reported as milligrams of phosphorus per liter.

Ice Thickness

Vertical thickness of ice. Only the portion of the frozen block that represents the water column within the ice block is measured as ice depth. Reported in centimeters.

Snow Depth

Vertical thickness of snow on the ice reported in centimeters.

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Page Last Modified: December 31, 2012