Water Level
Water level has been followed with water level monitors (piezometers) from Remote Data Systems, Inc. We used Model WL40 until January 2004 and have used Ecotone Series since then (the scales on the two models are equalized in the graphs). The monitor will read water level even when it gets below ground, and is set to read every 12 hours. Stored data are collected when convenient. When the water level is 25 inches below the reference point, most of the wetland area is dry.

The graph shows water levels for the years 2000 through 2002 and covers the period of stabilzation after mitigation was completed in early 1999. By 2002, the typical water level was higher and the variations were less extreme than initially. Both of these probably resulted from silting up in a low area at the north end of the wetlands. In 2000, the two sudden rises in water level in May and November can be correlated with unusually heavy rainfall for those two months. The small peak at the end of July coincides with a period of 3 days in which there was almost 2 inches of rain. In 2001, September was unusually dry with only half the average amount of rain.


The second graph (click on link to view it) compares the 2002 water level with that for 2004. The typical level is again slightly higher in 2004. The third graph compares daily rainfall with changes in water level for the first part of 2004 and shows a close correlation between rainfall and increase in water level. There is also in many cases a small rise following the post-rain drop which could be due to gradual drainage from the surrounding area.
Wetland Indicators
Apart from the type of vegetation, there are other characteristic indicators of wetlands which can easily be seen.
Moss on tree trunks
Moss line on tree bark: If trees are standing in water for any length of time, moss will grow on the bark. Usually mosses and lichens grow above the highest water level, while aquatic mosses and liverworts grow at a lower level which is more frequently saturated.

Iron film on water surface: This occurs in enduring pools of water. Much of the color in soil comes from iron in the oxidized form, Fe3+. In water-saturated soil there is little oxygen (anaerobic conditions), and this iron becomes reduced to the Fe2+ form. The reduced form has little color, so hydric or water-saturated soil has a gray color. Fe2+ is much more soluble than the oxidized form and is therefore available to living organisms. Chemosynthetic bacteria convert the iron back to its oxidized form and this, being less soluble, forms a film of precipitate on the water surface which looks somewhat like an oil-slick to the casual observer.

Local regions of oxidation of iron in hydric soil can also produce orange-brown streaks where rootlets have released oxygen.

Floating iron
Click on photos to enlarge