**2. Why are constructed wetlands utilized in the urban environment?**

Urban Stormwater: Best Practice Environmental Management (BPEM) Guidelines [9] outline the principles and objectives behind the use of water treatment devices such as wetlands by referencing SEPPs (State Environmental Protection Policies) of Victoria, Australia. These objectives are clear: to preserve the beneficial uses of local waterways, including:

*Understanding the Role of Constructed Wetlands in Stormwater Management DOI: http://dx.doi.org/10.5772/intechopen.102912*


As urbanization increases, so too does the anthropogenic environmental impact, which includes pollutants occurring from human lifestyle activities, building and infrastructure, construction activities [9], urban vehicular emissions and increased stormwater runoff volume peaks and nutrient loads due to hard surface runoffs inherent in typical urban development [13]. Constructed wetlands, as part of a SUDS (Sensitive Urban Drainage System) can be used to mitigate these impacts [14], and within Victoria, Australia they are typically installed as part of large-scale urban developments to comply with the BPEM guidelines.

Wetlands are cost-effective treatment systems that can be used to treat urban stormwater runoff. The advantages for installation of constructed wetlands, including "(1) low cost of construction, and, especially, maintenance; (2) low energy requirements; (3) being a 'low-technology' system, they can be established and run by relatively untrained personnel; and (4) the systems are usually more flexible and less susceptible to variations in loading rate than conventional treatment systems" [3]. In addition, "the major disadvantages of constructed wetland treatment systems are the increased land area required, compared to conventional systems, and the possible decreased performance during winter in temperate regions" [3]. Under Melbourne Water's drainage Schemes, landowners and developers are fairly compensated for land use dedicated to wetlands, thus mitigating the disadvantage of the increased land area required [15]. As wetlands are integrated into large-scale urban development design and construction, they are typically designed to receive flows up to the 1 in 3-month ARI rainfall to minimize land take whilst treating to best practice.
