Transitions in Watermanagement in the Netherlands · Pieter de Boer . Rijkswaterstaat Outline/content • Introduction- water management and need for dredging in the Netherlands •

Transitions in Watermanagement in the Netherlands

Trends in dredging

Pieter de Boer

Rijkswaterstaat

Outline/content

• Introduction- water management and need for dredging in the Netherlands

• Developments in Policy’s and legislation and consequences for the dredging chain

• Examples (lake Ketel, waste policy’s and destinations of DM, disposal and treatment)

• Lessons learned, transition/”paradigmashift”

• Outlook 2005 – 20xx, EU Water Framework Directive

• Constraints - too detailed regulations

2 december 2010 Trends in dredging

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River basins in Europe


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Dredging of small waterways for drainage


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Water infrastructure


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Flood Control/Room for the river (dredging)


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Flood protection (dredging)


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Dredged material resource or waste ?

• In the past dredged material was a resource used for

– Relocation in the sea or rivers

– Raising the land

sediment dredging transport destination

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Due to contamination use of DM was restricted From about 1970 dredged material is regarded as a waste: disposal

Dredging chain became complex


operational level

ex-situresearch

relocation

direct use

treatment

disposal

use of product

in-situ investigation of quality

and quantity

residue

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Third National Memorandum on Water Management (1989)

Specific policy for the remediation of contaminated sediments (1993) and Guidelines for the design of disposal facility’s for DM (1993) Policy instrumented by means of existing legislative framework

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Soil Protection Act (198x)

• Prevention and remediation of soil-contamination (aquatic and terrestric in the Netherlands)

• Specific rules (in governmental decisions, for example with regard to oil tanks)

• Chemical Quality Criteria (SQC’s)

• 1997: Specific rules for remediation of contaminated sediments

• Inventory study, Follow-up studies

• Risk-assessment, Humans, Ecology, Groundwater, Surface water

• Renovation plans (permits)


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Lake Ketel projects

• Regional disposal capacity was needed for the execution of the remediation of lake Ketel (and other projects)

• Design and construction of confined Disposal Facility IJsseloog (1993 -2003)

• Remediation dredging lake Ketel (2003 – 2012) - accurate/precise dredging (every extra inch creates large volumes of DM)

• Research programs, - Mobility and behavior of contaminants (remediation, cdf) - Mapping of contaminated sedimants - Accurate Dredging Techniques


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Dutch guidelines for the design of a CDF for DM

Theme Subject Aspect Criteria

Isolation Quality of the pore-water Target level for groundwater quality

Emissie per ha. per jaar (flux;

advectief + diffusief transport)

Tolerable fluxes

ALARA Advective transport < 2 mm/jaar

Diffusive transport: minimize

IBC –

measures

Maintenance IBC- measures In good order

Unexpected circumstances It should be possible to intervene

“Removability” It must be possible to remove the DM if thought to be

necessary

Control IBC-measures Control on proper construction

Ground- and surface Field investigation (T0) and monitoring obliged in permits

Design of the

facility

Contact-area Minimize (maximize amount of DM/m2)

Permeability Minimize (advective transport < 2mm/jaar)

Rate of contamination Horizontal compartments

Redox-conditions Anoxic environment

Inherent safety Local Conditions Geology Impermeable (adsorptive) layers underneath the facility

Geohydrology Low velocity of groundwater and relative thin aquifers

In water Litle differences in water pressure between facility and the

aquifer

On land Facility (bottom) should be close tot the groundwater

Emission Groundwater Tolerable influence (emission) Volume of the facility


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Confined Disposal Facility IJsseloog (Lake Ketel)


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Accurate dredging techniques

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Sand separation techniques

hydrocyclones

sedimentation basins

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Chemical immobilisation and stabilisation (pilotscale)

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Indication of treatment and disposal costs (SedNet) Costs are site-specific

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Risks

Risks for

Groundwater

Toxic effects:

people, ecology,

surface water

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Hollandsche IJssel, Sediment core and tidal flat

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Moordrecht, Capping

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22 26 april 2010

Lessons learned 1: Decision making on remedial dredging

• It is not realistic to clean up all contaminated sediments (river floodplains, estuaries), Prioritisation is needed

• Eco-surveys, chemical analysis & bioassay (TRIAD-approach) did not match (jackpot)

• Sediment Quality Standards (total loads) are not a good indicator for risks (only useful for source control)

• Free (bio-available) chemical concentrations in water (toxicological data) do relate to ecological risks

• If pore-water concentration in sediments = surface water concentration, than remediation by dredging will not solve problems

• Decision making about remediation should be done site specific by assessing

actual risks (bio-availability of contaminants is decisive (multi-substances, combitox).

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Lake Ketel


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24 26 april 2010

Lessons learned 2: Treatment and disposal

• Treatment can be a means to make dredged material suitable for use, but it should be cost-effective and there should be a market for the products

• Only simple treatment techniques are used on a large scale

• Chemical immobilisation is only done on pilot scale

• Thermal immobilisation is not economically feasible

• Most treatment is done to reduce the volume for disposal

• Sub-aquatic confined disposal in CDF’s is a cost-effective and environmental acceptable solution for large volumes of (heavily) contaminated dredged material

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25 26 april 2010

Lessons learned (3): Legislation

• Dredged material is on the borderline of water, soil and waste

regulations.

• Legislation for all the mentioned sectors is relevant to dredging

• Very complex legislative framework hampers dredging

• Realistic and tailor-made solutions are needed

• Dredged material is essential for aquatic systems. Relocation into the aquatic system is the first option to consider.

Figuur 4.1: Positionering knelpuntenFiguur 4.1: Positionering knelpunten

Algemeen

Wbb

Wm

WbmBsb

Wvo

Wvz

Wbr

ABM

/ABROverig

BeleidsniveauBeleidsniveau

Niveau van wetgevingNiveau van wetgeving

Regelgeving/Regelgeving/

richtlijnenrichtlijnen

Operationeel niveauOperationeel niveau

- saneringsdoel (5)

- eisen bagger-

nauwkeurigheid (7)

- richtlijn NO (9)

- verhaalsacties (11)

- verificatie

sanerings-

resultaat (8)

- status

functie

gericht

saneren (13)

-multifuncti-

onaliteis-

principe (2)- imago (3)

-proceduretijd

bij wijziging (4)

-begrip

verontreinigde

Specie (10)

F&F

- methode

van risico-

beoordeling (6)

- begrip

‘werk’ (10)

- relatie

Wbb/Wvo (12)

- bagger

als afval (1)

- onduidelijkheid

over storten (5)

- reikwijdte (6)

- ladder v

Lansink

- procedures

- interpretatie

- definitie reinigbaarheid (4)

- partij indeling (6)

- protocollen (9)

- veel rompslomp (1)

- te detaillistisch (2)

- afzetbaarheid (5)

- residu stromen (8)

- rigide werking (1)

- begrippen (2)

- onvolledig (4,5)

- relatie Wvo (6)

- reikwijdte (8)

- kosten (3)

- onderzoeks-

inspanning (7)- middel-

voor-

schriften (2)

- interpretatie (1)

- begrippen (1)

- status CTT (2)

- correctheid (3)

- ontheffings-

duur (4)

- invoeerings-

moment (5)

- procedures

vergunningen (1)

- rigide

werking

tijdelijke

acties (2)

- interpretatie (6)

- invulling regels (7)

- definities ( 4)

- nazorg

Inspanningen (5) - saneringsdoel (1)

- verplicht saneren

locale bronnen (2)

- reikwijdte storten (3)

- financiering (1)

- bestemmen (2)

- verantwoordelijkheden (3)

- interpretatie (4) - rollen (7)

- communicatie (6) - Arbowet (9)

- meldingen(4)

- vergunningen geluid (8)

- gebrek aan

kennis (2)

- procedure tijd

vergunningen (4)

- imago bij

bestemmen (5)

- afstemming (1)

- tegenstrijdig-

heden bij

vergunningen (3)

- doel versus

middelen bij ver-

gunningen (8)

- ondergrens-

problematiek (9)

- afstemming (1)

- wisselend

beleid (7)

- inconsistenties

in beleid (7)

- gemis aan

samenhang (7)

- afstemming (1)

- ondoel matige

procedures (6)

- verande rende

wetgeving (7)

- doelmatigheid

versus recht-

matigheid (10)

AKR

- reikwijdte (7)

- relatie met

praktijk (1)

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Dutch policy note (2005) on the management of DM

• Dredging = Watermanagement

• Use of DM (and soil) is a policy objective, treatment is no longer a policy objective

• DM is waste if use in the (aquatic) environment is not allowed

• Remediation of contaminated sediments is necessary if contaminated sediments are the cause for not fulfilling the WFD objectives - good chemical water quality - a good ecological potential/status

Quotes from Sednet: - “Sediments are an essential, integral and dynamic part of river ecosystems” - “Sediments are not a waste, but a valuable, natural resource that deserves protection, conservation or even restoration at some sites”


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Soil Quality Decree (2008)

• New legislation has been drawn up to encourage the use of dredged material for placement on banks, relocation at sea and filling of pits.

• Most dredged material can be re-used

• Only a small amount of DM has to be disposed of in Confined Disposal Facility’s


Operational level

ex-situ

(chemical) Research

relocation

direct use

treatment

disposal

use of product

in-situ investigation of quality

and quantity (chemical and

other methods)

residue

EU-WFD, OSPAR/LC

Water Act and decisions

(2009), Natura 2000

Soil Quality Decree

(2008),

Environmental

management Act (198x?)

EU Waste Directive

Landfill Directive

EURAL


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Summary and conclusions

• Dredging = Water management and vice versa

DM management = source control

• From 1993 until 2008 a large amount of DM had to be treated or to be disposed of in specific facility’s (CDF)

• Nowadays most of the Dutch DM can be used beneficialy (source control)

Remediation

• From 1993 until 2010 improving sediment quality (and reduction of environmental risks) was the goal for remediation

• Nowadays the policy-objective is to have a good quality and functioning of waterbody’s

Risk assessment

• SQC (mg/kg) are useful for source control, but not a good starting point for risk assessment and decision making on remediation

• Bio-available fractions are correlated to (ecotoxic) effects

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Outlook

• It is uncertain if remediation of contaminated sediments will be neccessary in the Netherlands to reach the goals of the WFD.

• How to deal with methods (for example: Tenax-extraction, Biotic Ligand Models) for assessing bio-available fractions of contaminants (for improving decision-making on sediment remediation).

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Thank you for your attention

Documents

Transitions in Watermanagement in the Netherlands · Pieter de Boer . Rijkswaterstaat Outline/content • Introduction- water management and need for dredging in the Netherlands •