Environmental Engineering Reference
In-Depth Information
FIGURE 19.2
Constructed.wetland.cell,.Putrajaya,.Malaysia.
wetland.area..Putrajaya.Wetland.with.its.high.diversity.of.plants.and.ish.has.
attracted.various.types.of.wildlife.including.more.than.100.species.of.birds.
and. insects.. The. introduction. of. insectivorous. ish. has. controlled. mosqui-
toes,.a.potential.hazard.of.constructed.wetlands.in.hot.climates.
The.wetlands.have.generally.shown.good.water.quality.improvement,.but.
silt. run-off. from. surrounding. development. land. has. resulted. in. low. pol-
lutant.removal.in.some.months.especially.during.the.wet.seasons..Siltation.
has.resulted.in.the.wetland.bed.becoming.shallower.and.terrestrial.weeds.
have.invaded.the.wetland.cells..To.ensure.the.sustainability.of.the.wetland.
system,.Putrajaya.Corporation.has.implemented.the.Polluters.Pay.Principle,.
where.developers.who.cause.siltation.in.one.wetland.cell.will.be.responsible.
for.the.desilting.work.and.wetland.plant.replacement.
BMPs. can. be. retroitted. under. a. number. of. conditions. including;. at. the.
time. of. building. refurbishment;. during. drainage. improvement. for. large.
areas. such. as. trading. estates. or. where. there. are. unsatisfactory. CSOs;. and.
through.incentives.to.property.owners.to.disconnect.roof.or.driveway.run-off.
from.the.public.drainage.system.(Gordon-Walker.et.al.,.2007)..When.select-
ing.ponds.or.wetlands.for.retroitting.or.construction.on.new.developments,.
the.requirements.for.low.attenuation,.water.storage,.or.pollution.treatment.
should. be. considered.. Systems. with. a. high. degree. of. permanent. pool. vol-
ume.have.dissolved.oxygen.and.redox.potential.conditions.that.may.lead.to.
remobilization.of.contaminants.in.the.sediment..These.factors.are.overcome.
in.constructed.wetlands,.with.their.characteristic.cycles.of.illing.and.drain-
ing.(Wong.et.al.,.1999)..Headley.and.Tanner.(2006).suggest.that.loating.treat-
ment. wetlands. may. be. suitable.for. incorporating. into.stormwater. wetland.
systems.and.especially.those.suffering.vegetation.decline.due.to.inappropri-
ate.water.depths.and.excessive.inundation..A.Water.Environment.Research.
Foundation. (2009). study. found. that. the. level. of. maintenance. speciied.
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