Hydrological Assessment of Wetland Sites

I.    Purpose:

            In addition to soils and vegetation, hydrology defines wetland boundaries.  Hydrological influences on wetlands are dynamic.  Monitoring the presence and depth of water helps to evaluate wetland conditions.

II.   Equipment:

            1.            Waterproof data sheet and clipboard

            2.            Pencil

            3.            Base map showing sampling sites

            4.            1 meter measuring stick, graduated in millimeters

            5.            Global positioning unit (GPS)

            6.            Waterproof hip waders

            7.            Raincoat

            8.            Insect repellant

            9.            Hat

            10.            Head Net

            11.            Sunblock

            12.            Drinking water

III.  Procedure:

1.  The hydrology of each wetland is assessed once a month during the growing season, when the soil, at a depth of 20 inches, is at or above biological zero (5°C).  Generally, between May15 and September 30.  Each wetland should be visited at approximately the same time each month (plus or minus 5 days) so that the visits are spread at approximately monthly intervals.  Hydrological measurements should not be made within a five-day period following an extreme rainfall event.

2.  Supply the following information on the data sheet:  name of the wetland site, transect number, investigator’s initials, date, and weather.

3.  During the first visit to the site the physical location of the sampling points, as designated on the base map, should be determined.  The locations can be determined using the base map, point markers and GPS coordinates.  Each wetland site is divided into long, narrow sections called transects, identified by Roman numerals.  The individual sampling points, identified by lowercase letters, are positioned along each transect.  Together, a Roman numeral and lowercase letter “name” an individual sampling point.  Sampling points are marked by orange-tipped PVC pipes standing between 1.22 and 1.83 meters above ground.  Each marker is labeled with sampling point name and GPS coordinates. 

4.  At each sampling point, record the presence or absence of standing water on the first and subsequent visits.  If standing water is present and it is possible to reach the sampling location, the depth of the water should be measured and recorded on the data sheet.

5.  Record the presence or absence of any additional primary or secondary wetland hydrology indicators (listed on the data sheet).

If you have comments/questions, please contact Dr. Meiyin Wu, Dr. Dennis Kalma or Boquet River Association . 

This page was last updated on January 08, 2007 .