Hamburg, 7-8 October 2009 rps.nl

Hydromorphological challenges for sediments

Oscar van DamTeam leader water management RPS BCC

with contributions of Bram de Groot and Arnold Osté

Hamburg, 7-8 October 2009 rps.nl

Hydromorphology?

Definition:“The knowledge of the shapes in the landscape as created under the influence of water.”

Hamburg, 7-8 October 2009 rps.nl

News: hydromorphology and sediments

NRC Handelsblad & Flanders Today

Hamburg, 7-8 October 2009 rps.nl

1. WFD and hydromorphology2. Sediments and ecology3. Examples4. Challenges

Sediments and hydromorphology; a true challenge!

Hamburg, 7-8 October 2009 rps.nl

Water Framework Directive

European legislationImproving water quality & ecologyMonitoring:

Chemical-physicalBiological=> Hydromorphological

Hamburg, 7-8 October 2009 rps.nl

WFD in NL

Water typesR-type, rivers, creeks and tidal riversM- type, lakes, ditches and canalsK&O-types, coastal waters

MonitoringHandbook HydromorphologyFact sheets per parameter

Sediments?

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Hydromorphology in Hamburg?

Natural flow

Bank protection

Soil type

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Sediments and ecology

Base for plant rooting Home for macro faunaStructure differentiationHunting and foraging

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Sediment related parameters coastQuality element Parameter

Morphology

Water depth distribution

Soil type (natural, artificial)

Substrate composition

Tidal zone: a. Type of inter tidal areab. Dry period duration

Hamburg, 7-8 October 2009 rps.nl

Example: coastal sedimentation

Water region: Dutch coastProject: the Sand Engine

Problem:Disappearing Dutch coastsSolution:10-year cycle sand suppletionProblem:Extinction marine beach life

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Example: coastal sedimentationSolution – Building with nature:

Reconstruction large sediment islandNatural gradual sediment distribution

Artists .Impression .

Source: http://www.zandmotor.nl/ Source: http://www.zandmotor.nl/

Hamburg, 7-8 October 2009 rps.nl

Sediment related parameters riversQuality element Parameter

Continuity Possibility to pass barriers for sediment

Morphology

Drainage patternCross section and extent of naturalnessSubstrate constitution bed

Erosion / sedimentation structures

Hamburg, 7-8 October 2009 rps.nl

Example: reconstructing river bed

Water region ‘Velt en Vecht’Project: Mariënberg

Enlarging winter bed 70 haDigging new side gully

Hamburg, 7-8 October 2009 rps.nl

Example: reconstructing river bed

Ecological goalsNew riparian forestNew habitats for macro fauna and fish

Hydromorphological improvementsMore natural river flow (meandering)More natural sediment distribution

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WFD sediment related measures

Examples 2010 – 2015State water board (paus-table)

Lowering flood bed - 1544 ha - M€ 2,4Water soil improvement - 12.448 ha - M€ 176,0New side gullies - 78 km - M€ 34,3Fish passages - 218 sites - M€ 23,9

Hamburg, 7-8 October 2009 rps.nl

Challenges!

Scientists:Monitor hydromorphological impact?Hydromorphological risk assessment?Effects WFD measures?

Hamburg, 7-8 October 2009 rps.nl

Challenges!

Policy makers:Decide on which measuresAllocate money for:

MeasuresMonitoringMaintenance

Inform the public!

Hamburg, 7-8 October 2009 rps.nl

Challenges!

Dredgers and contractorsInnovative solutionsSediment typesIntegrated maintenance contractMonitoring methodologiesand techniques

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Where do sediments fit in?

Catchment management plans?Sediment frame work?Marine Strategy Framework?

Hydromorphology!

Example dry fall period West Scheldt

Hamburg, 7-8 October 2009 rps.nl

Discussion!?

Acknowledgements:Gerard Duursema, waterschap Velt en VechtBas Kers, Rijkswaterstaat DID