Linking Water Treatment with Wetland Restoration - Restorative Redevelopment of Devastated Ecocultural Landscapes - page 362

The assessment and analysis techniques that are now available, including hydro-
dynamic modeling, hydrologic water balance models, and landscape appraisals, far
exceed in complexity, precision, and power those available even just a decade ago.
Importantly, with regard to the Iraqi marshlands, treatment wetland technologies are
scalable (i.e., they can be built for small sites and then scaled up to a large scale).
At the same time, this becomes a good way to build knowledge and move forward,
and in this regard stakeholder input is an important tool in terms of deciding what
is desired and creating a plan to achieve this (see chapter 4). The well-known educa-
tional, recreational, and wildlife benefits of wetland construction (France 2003) are
tools in themselves, useful in that they help persuade others that these technologies
can be applied.
The conceptual model is based on building a “treatment train” ( sensu Apfelbaum
2005) where initially there are some pretreatment basins where the heaviest con-
taminant loads are removed through aeration and settling. Next the water flows
into a treatment marsh of alternating shallow and deep zones, perhaps to a larger
system for habitat enhancement, followed by either discharge to a receiving water
body or recycling back to the beginning of the system. The goal is to design these
wetlands within their tolerance range in terms of constituent and hydraulic loadings
(Bays 2002).
There are really several types of wetland technologies that can be engineered
(Bays 2004). The simplest is a natural wetland where effluent is applied to a natural
system and the engineering is simply constructing a distribution system and letting
the system process that wastewater naturally. In the real world, there is an open marsh
and the distribution system might be a gated pipe perhaps located on a boardwalk
for access and maintenance. Another type of technology is surface-flow constructed
wetlands which more or less resemble what people think that a traditional marsh
should look like. Typically the system is enclosed with berms and contains plants
in shallow water. One such example is the Dupont Nylon Treatment Wetlands in
Victoria, Texas (Bays 2002), which receives industrial wastewater from a treatment
plant and processes it through a series of treatment wetland “cells.” Significantly, this
particular treatment wetland also contains habitat islands and open-space features,
and thus represents a good example of compatibility between treatment as a reme-
diation tool and habitat creation as a restoration tool. The point is that such surface-
flow wetlands can offer significant recreational educational opportunities (Bays et
al. 2002; France 2003). In the United States there are many examples of such sys-
tems that have been built as outdoor laboratories or educational and bird-watching
facilities. Industrially contaminated waters are also treated by surface-flow wetlands
such as the system in Richmond, California, which receives and removes petroleum
refinery runoff effluent. One example of a surface-flow wetland with particular refer-
ence to the environmental conditions in southern Iraq is the Sweetwater Wetlands
in Tucson, Arizona (Bays 2002), another arid region where there are just a few cen-
timeters of rainfall a year. This wetland is designed to be a flow-through treatment
wetland to improve the quality of the reclaimed water prior to its use to recharge the
groundwater as well as provide a wildlife habitat marsh with educational and recre-
ational benefits (Figure 18.1).