Purpose:

The water quality team is responsible for collecting data to determine the influence of the Clark Fork Delta Restoration on water quality.  Water quality monitoring is a powerful tool that helps us assess how the physical, chemical and biological characteristics of a waterbody respond seasonally, temporally (over time) and in response to certain activities.

Physical characteristics can include water temperature, dissolved oxygen, conductivity, total dissolved and suspended solids, transparency, turbidity, odor and color. Chemical characteristics can include pH, biological oxygen demand, metals, phosphorous, nitrogen, organic carbon and many others.  Biological characteristics can include various types of bacteria including E. Coli and coliform bacteria, as well as phytoplankton (algae) and macroinvertebrates.

The physical, chemical and biological characteristics of a waterbody can reveal a lot about water quality.  For example, the amount of dissolved oxygen (a physical characteristic) in the water can indicate if a particular waterbody is suitable fish habitat.  In general, dissolved oxygen concentrations below 6 mg/L are detrimental to fish survival.  Chemical characteristics such as the amount of total phosphorous in the water can be good indicators of nutrient loading.  Excessive amounts of phosphorous can result in nuisance algae blooms and exacerbate problems with aquatic invasive weeds.  Lastly, bacterial concentrations (a biological characteristic) in water can act as a good indicator of fecal pollution, either from humans or animals.

In this case, we are interested in answering several questions including:

1. What is the ambient water quality for locations undisturbed by the Clark Fork Delta Restoration and how does this change over time?
2. How do restoration activities influence water quality within the Clark Fork Delta?
3. How does water quality change as the result of restoration within the Clark Fork Delta and does this change over time?

Sampling Methods:

While there are many physical, chemical and biological tests that can be performed to assess water quality, many are outside the scope of the restoration project.  However, several tests can be performed in the field such as water temperature, pH, transparency and dissolved oxygen.  These field tests are performed using the following equipment and field test kits:

• Water temperature – Vertical point bottle sampler (Figure 1).  The vertical point bottle sampler has the capability of collecting a sample from a discrete depth in the water column. The sampler has an internal thermometer, which measures the temperature of the water.

Figure 1. Data collector measuring water temperature using a vertical point bottle sampler.

• Transparency – Secchi Disk (Figure 2).  A Secchi disk is used to measure how transparent the water column is.  The data collector lowers the black and white secchi disk into the water until it disappears.  The depth at which the disk disappears is called the secchi depth. A variety of factors can influence transparency including the color of the water, algae, and suspended sediments. 

Figure 2. A Sechhi disk that is about to be lowered into the water to measure transparency.

• Dissolved oxygen – Hach® Dissolved Oxygen Test kit (Figure 3).  The dissolved oxygen test kit uses a simple chemical titration to determine the concentration of dissolved oxygen in the water.  The Hach® kit uses a modified Winkler test where the amount of dissolved oxygen is directly proportional to the titration of iodine with a thiosulfate solution.

Figure 3. Hach® Dissolved Oxygen Test kit

• pH – Hydrion pH test kit (Figure 4).  pH is a measurement of how acidic or how basic an aqueous solution is.  A pH less than 7 is considered acidic while a pH greater than 7 is considered basic.  The Hydrion kit uses a colorimetric test to indicate how acidic or basic the water sample is.

Figure 4. A data collector comparing a water sample treated with a pH indicator solution to the comparison chart.

In addition to the physical tests described previously, certain chemical tests can help discern if restoration activities influence water quality.  Since the Clark Fork Delta Restoration Project is designed to address erosion of wetland habitat, tests for phosphorous and nitrogen are beneficial as these elements can be indicators of erosive processes.  Water samples will be sent to a certified laboratory in Coeur d’Alene for phosphorous and nitrogen analyses.  Figure 5 shows an example of total phosphorous data collected from the Clark Fork Delta from 2012-2014.

Biological testing for total coliform bacteria can also be useful indicator of how erosion influences water quality. Coliform bacteria are a natural component of soil ecosystems and their increased presence in the aquatic environment can be the result of erosion (among other processes).  Total coliform analysis is another test that is best conducted by a certified laboratory.

Figure 5. Total phosphorous data collected at the Clark Fork Delta from 2012-2014 (Source: Lake Pend Oreille Waterkeeper).

Timeline:

• Spring 2015 – Initial water samples collected from pre- and post-restoration activity areas of the Clark Fork Delta.  Field tests will be completed on-site and wet-chemistry tests will be sent to the lab for analysis. Field and laboratory data analyzed upon completion.
• Summer 2015 – Water samples collected from pre-and post-restoration activity areas following the “spring refill” of Lake Pend Oreille.  All tests will be performed and data handled as previously described.
• Fall 2015 – Water samples collected from pre-and post-restoration activity areas following the “fall drawdown” of Lake Pend Oreille.  All tests will be performed and data handled as previously described.