New Water Policy and Practice Issue 4, Number 1, Fall 2017 | Page 36

New Water Policy & Practice Journal
mal settlements set up temporarily for refugees, suggesting that Sustainable Drain-
age approaches may provide some answers to these issues.
2. Sustainable Drainage Systems
S
ustainable Drainage Systems or SuDS mimics natural systems in that it en-
courages the infiltration of water into the ground, its short-term retention
or long-term detention, and its slow conveyance to the receiving waterbody
(Charlesworth and Booth, 2017). These processes are carried out via various de-
vices which address the SuDS square of benefits, shown in Figure 1, which balanc-
es equally: attenuation of the storm peak thereby reducing flooding, improvement
of water quality, provision of amenity benefits for the populace and promotion of
biodiversity (Woods Ballard et al., 2015). This balance is achieved via various indi-
vidual devices which can be used alone, or can be designed together into a manage-
ment or treatment train (see: Charlesworth, 2010). These devices include pervious
surfaces such as porous or permeable paving systems (PPS), swales, filter strips,
green walls and roofs, wetlands and ponds; for further details see Charlesworth
and Booth (2017). If designed properly, and with cognisance taken of local condi-
tions, SuDS can be installed into the most challenging of environments: informal
settlements and refugee camps.
Figure 1 The SuDS equal balance be-
tween water quality, water quantity,
biodiversity and amenity (after Woods
Ballard et al., 2015).
3. Challenging Environments
3.1 The tropics
SuDS are relatively easy to design into temperate environments (see Watkins and
Charlesworth, 2014), but challenges arise with the intense, relatively short dura-
tion rainfall experienced in tropical regions allied with disease vectors such as
mosquitoes and nuisance animals including snakes. The importance of suitable
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