How to Use IRIS?

1. Identify Areas to Instrument

2. Install 5 Replicate IRIS Devices

Within your study area, determine if there are various sub areas (plots) within the site that need to be evaluated. There often are “sub areas” with different hydrology or soil conditions. Some regulators recommend that sub-areas be no larger than 1 acre, although in some cases, natural variability would warrant even smaller sized study areas

2. Install 5 Replicate IRIS Devices

Because soil redox conditions are highly variable, 5 replicate IRIS devices should be installed within a plot. (This is what is recommended by the National Technical Committee for Hydric Soils - NTCHS).

3. When to Deploy IRIS?

2. Install 5 Replicate IRIS Devices

4. Monitoring with Sequential Deployments

Installation should be early in the growing season when:

i. Water tables are high

ii. Soil temperatures are warm enough to support microbial activity

iii. In the Eastern US this typically means that deployments should begin approximately:

1. Mid, South FL - Anytime

2. N. FL - Mid to Late Feb

3. GA, SC - Late Feb to Early March

4. NC, – Early to Late March

5. VA – Mid March to Mid April

6. MD, DE – Early to Late April

7. PA, WV – Mid April to Mid May

8. SNE – Late April to Late May

9. NNE – Mid May to Mid June

iv. In CA, this would mean after winter rains have caused water tables to rise.

4. Monitoring with Sequential Deployments

Because temperatures and seasonal warming can vary from year to year, it is challenging to predict when is the best time to install IRIS in a given year. Therefore, it is sometimes useful to plan to deploy two sets of IRIS devices to help ensure the most effective assessment of a site. These can be deployed sequentially - 4 weeks apart, or the deployments may be staggered.

5. How Long to Deploy IRIS?

4. Monitoring with Sequential Deployments

5. How Long to Deploy IRIS?

a. The standard time for deployment of IRIS devices is 1 month (based on NTCHS protocols).

b. Longer Deployments?

i. In general, deployments longer than 1 month should probably be avoided as they may lead to false positives.

ii. Long deployments may, however, be used for reconnaissance purposes. When results from a long-term reconnaissance deployment suggest that an area might have hydric soils, that can be followed up with more conventional assessment (1 month deployment) .