Plants and Soils of the Walnut Wetlands
Visitors: Use the links above to learn more about specific aspects of the Walnut Wetlands.
Click to return to the soil descriptions page...
Hydric Soils
Hydric soils are commonly associated with wetland areas and are strongly influenced by the presence of water. A soil is considered hydric if it has been flooded or saturated with water long enough to become anaerobic, meaning there is no oxygen present.
The lack of oxygen has many effects on the soil. Organic matter (usually in the form of decomposing plant material) often accumulates in these soils. Chemical processes can result in grey soil colors, quite different from the usual reddish or yellowish color of soils. Sometimes mottles, or "spots" of different color, appear in the soil profile. Also, hydric soils support plants adapted to these oxygen-free conditions, including some unique plants that are described on other pages in this site.
The maps below show the hydric soils of the Walnut Wetlands. Most of the hydric soils are found near Walnut Creek or the other small creeks that come off it. Not surprisingly, the Cypress Marsh, Northern Floodplain, and Southeast Swamp all have hydric soils. However, notice that hydric soils also extend into the Rochester Heights neighborhood and other built-up areas. The soils in these areas do not have to be currently flooded with water and oxygen-free to be called hydric. The soils, however, did form under these conditions.
Hydric soils and wetlands are not the same thing. An area must have hydric soils, wetland-adapted plants, and the presence of water for some time during the year to be considered a wetland.
Two-dimensional (above) and three-dimensional (below) relief maps of the Walnut Wetlands area. Hydric soils can be found along Walnut Creek as well as the many creeks that flow into it.
Image map (below) showing that hydric soils extend into local neighborhoods and other built-up areas.
What about the colors in the map legends?
The eight colors above correspond to different soil series. A soil series is group of related soils. The soils in a series have very similar physical characteristics and soil profiles, so they are described together. The Natural Resources Conservation Service, a government agency that maps soils throughout the U. S., stores all of these soil series descriptions. They include information such as where in the U.S. a soil series can be found, what types of plants it supports, as well as its physical properties. Below are links to the eight series listed in the map legends.
Click to return to the soil profile descriptions page...