29
S
tep
3–A
ssess potential
impacts
,
effectivenessand
…
compare
Assessingeffectiveness,cost-effectiveness and impacts requires that you investigate
the expected contributions of proposed measures (whether they are NWRM
and/or grey infrastructure) to solving yourmain problems.
Informationabout howpotentialmeasuresmight affectwater retention in thefirst
place is crucial,andhow this in turnmight affect the (ecosystem) servicesdelivered
andcontribute to theachievementof policyobjectives youhave identifiedasbeing
relevant for your territory.Youneed to assess all the costs, i.e.financial (investment,
operation,maintenance and renewal) costs, and also indirect economic costs and
whenever relevant environmental costs.
You will then need to assess the
potential effectiveness of proposedmeasures
at contributing to addressing the pressures and achieving the different policy
objectives you identified under Step 1. Because of the characteristics of NWRM,
their effectiveness cannot be taken for granted.They will be more effective in
some situations thanothers, andmay not be the ‘best’ solution everywhere.
15
16
TheeffectivenessofNWRMand their influenceonecosystem servicesdependson:
ņ
ņ
Local conditions and the relative location of the measures in the
catchment.
The impact and effectiveness of measures such as buffer strips,
riparianafforestationor groundwater rechargedifferdependingon location.
ņ
ņ
The spatial
area covered
by the measure (e.g. how many hectares,
kilometers of river or number of green roofs).
15
JRC (2013) River BasinNetwork onWater FrameworkDirective andAgriculture: practical experiences and
knowledge exchange in support of theWFD implementation, EUR 25978 – Joint ResearchCentre – Institute for
Environment and Sustainability
16
Natural England (2011) Protectingwater from agricultural run-off: buffer strips,Natural EnglandTechnical
InformationNoteTIN100
Inverstigating theeffectivenessofNWRMunderdifferent contexts
JRC (2013)
15
summarises the impact of agricultural measures and notes that 5m buffer strips
can remove between 15 to 20% of phosphoruswith this range rising to42-96% inhilly areas.
These resultshighlightboth thedifferencebetweencontextsand thepotential forwide ranges
in impactswith similar contexts. The design of themeasuremay alsoneed to reflect location:
Natural England (2011)
16
suggest that a 6m buffer stripmay be sufficient to slow surfaceflow
on slopesof less than7° (medium soils) or11° (sandyand light soils),whereasa12mbuffer strip
mightbe requiredon steeper slopes .
Illustration6
Enhancingpolicycoordination tomake themostoutofNWRM inyourplanningprocess
