Geoscience Reference
In-Depth Information
Figure 13-7.
Map of the lower Tigris and Euphrates drainage system in Iran and Iraq showing marsh areas (dark
gray). Produced by A. Dailey. Map made with data from Natural Earth, Global Administrative Areas, and World
Wildlife Fund Terrestrial Ecoregions Database (Olson et al. 2001). Accessed online
<
www.naturalearthdata.com
>
<
http://www.gadm.org/
>
and
<
http://www.worldwildlife.org/science/data/item6373.html
>
February 2011.
Wetland restoration and enhancement
projects may be completed relatively quickly
with functions, vegetation and animal species
re-colonizing within the span of a few months
to years given the right conditions and neces-
sary engineering or other structural changes
implemented. The type of wetland generally
provides a good indication of how long a res-
toration project may span. For instance, it may
be relatively easy and quick to establish a ripar-
ian wetland given the reinstatement of the right
topographic and hydrological conditions (Kusler
2006). On the other hand, Zedler and Kercher
(2005) suggested that tussock-forming sedge
meadows could take decades to establish fully.
Meanwhile, forested wetland requiring trees
to mature or a peatland necessitating organic
matter accumulation might take substantially
longer time and management investments and
require careful planning and i ne hydrological
adjustments (Kusler 2006). Similarly, wetland
creation projects require substantially greater
investments of time than restorations and may
take several decades to approximate natural
conditions.
13.6 Artifi cial treatment wetlands
The numerous ecosystem functions offered by
wetlands provide the impetus to reproduce such
conditions artii cially to benei t both humans
and the environment. Constructed, artii cial or
treatment wetlands, as they are interchangeably
called, are found across the globe. By 2004,
there were some 5000 operational waste-water
