Appendix B: Ponds and wetlandschecklist /
Table B.20 Minimum design requirements: ponds/wetlands
Parameter / Minimumdesignrequirements(MDRs)
Length to widthratio / 3:1
Maximumdepthofpermanent water / 2m
Maximumsideslopes / 1in3
Maximum depth of aquaticbenchbelowpermanent water level / 400mm
Sizeofpermanentpool / ≥ treatment volume, V
t
Table B.21 Minimum design requirements: ponds/wetlands
Generalinformation
SiteID
Asset ID(s)
Pond/wetland location(s) and co-ordinates / Drawingreference(s)
Dateofassessment / Specificationreference(s)
Primary function(s) of pond/wetland / Attenuation/treatment
Check / MDR / Summarydetails1 / Acceptable(Y/N) / Comments/remedialactions
Dimensions(Section23.2)
Length (m)
Maximumandminimum width–at
permanent water level (m)
Length:maximumwidthratio /
Topsurfacearea(m2)
Sideslopes(1in ?) /
Depthof permanentwater –maximumand minimum (m) /
Freeboard(m)
Aquaticbenchwidthandslope(m, 1in?) /
Safetybenchwidthandslope(m,1in?) /
Inflows(Section23.8.1)
Provide a description of thecontributing
catchmentlanduseanditssize(m2)
DoesthedesignincludesuitablesiltInterceptionupstreamof system?
Doesthedesign include:
▪asuitable inlet design
▪appropriateenergy dissipation?
Outfallarrangements(Section23.8.2)
Provide details of any flow controlsystems, overflowarrangements andlimitingdischarge rate frompond/wetland
Is a geomembranerequired to preventinfiltration? If yes, give reason
Depthtomaximum likelygroundwater
level (m)
Storage(Section23.4)
Designeventreturnperiod(s)(years)
Maximumrise in water level(s)forthedesignevent(s)(mm) /
Maximum water depth(s) at designevent
conditions(m)
Maximumdesignstorage volume(s)(m3)
Levels aroundtheedge of thepond/wetlandappropriatetocontaindesigndepthsofwater?
Waterqualitytreatment(Section23.5)
For the 1 year,30 min eventconfirm:
Permanent pool volume is sufficientfor /
effectivetreatment
Or
Flow velocity is acceptableforeffective /
treatment
Landscape/biodiversity(Sections23.6,23.7and23.10)
Istheresufficienttreatmentupstream ofthepondtoallowdesignamenity and biodiversityobjectives to be delivered?
Doesthevariation in permanent waterdepth havethe potential to createbiodiverse habitats?
Doesthedesign of thepondfulfilobjectives of availability of differenthabitatsincluding:
▪deepwater
▪marginal
▪dry/damp
▪other
A plantingschedule is provided,showingspeciesandplantingpreferences.Istheplantingdemonstratedappropriateforthehabitatspecified?
Willplantingsbeestablishedorrelyonnaturalcolonisation?
Have locallyappropriate native plant speciesbeen used?
Indicatethenumberof differentplantspeciesused(not a monoculture)
Istheproposedpond/wetlandplantingappropriatetothelocation,andwithrespectto access andmaintenance?
Where relevant, confirmplantingdesigndoes not adverselyimpact highwayvisibility and safetyrequirements (checkwithhighway authority)
Istheproposedtopsoilprofilesuitable to sustaintheproposed plantspecies?
Criticalmaterialsandproductspecifications(Section 23.9)
Geomembrane
Geotextile(non-woven)
Topsoil
Other(includingproprietary systems)
Constructability(Section 23.11)
Arethereanyidentifiableconstructionrisks?Ifyes,stateandconfirmacceptableriskmanagementmeasuresareproposed
Maintainability(Section23.12)
Confirm that accessformaintenanceis
acceptableand summarisedetails
Aretherespecific features that are likelyto posemaintenancedifficulties? If yes,identifymitigationmeasuresrequired
Pond/wetlanddesignacceptability / Summarydetailsincludinganychangesrequired / Acceptable(Y/N) / Datechangesmade
Acceptable:
Minorchanges required:
Majorchangesrequired/redesign:
Note
1Ifthereis an MDR(asindicated)confirmwhetherornotthisis met andprovidedetails of any variations.
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