Sustainable Dredged Material Management? Tools and ...€¦ · sustaining ecosystem services: Sediment-Ecosystem Regional Assessment (SEcoRA), Science of the Total Environment, 415:9-30

© 2012 Sabine E Apitz

SEA Environmental

DecisionsT ran s fo rm in fo rm atio n

in to ac tio n

Sustainable Dredged Material Management? Tools and Approaches for

Developing Integrated Sediment StrategiesSabine E. Apitz

SEA Environmental Decisions, Ltd.1 South Cottages, The Ford; Little Hadham, Herts, SG11 2AT, UK;

+44 (0)1279 771890; [email protected]

Transform information into action…©SEA Environmental Decisions, Ltd, 2012


Pathways for contaminated sediment impact in a typical EcoRA Conceptual Model

All complete exposure pathways have the

potential to cause

negative effects

Sediment itself, on the other hand, cannot be

treated as a typical stressor – it has both

desirable and undesirable roles in ecosystems

Sediment as Habitat:Sediment organisms play critical roles in ecosystem functioning

5 mm

Animal burrows

5 mm

pH imaging

O2 imaging

fluorescent SPI

O2 imaging

Benthic photosynthsiswww.cobo.org.uk

Sediment balance also essential. Sediment lack affects coastal and land defence...

Source: The Benefits of Using Dredged Material in Aquatic Systems, Lindsay Murray, Cefas, UK, SedNet, Venice November 2006

From van Baars, 2004

...but sediment excess creates other problems, whether deposited

or suspended

From Sediment Matters, Atkins Ltd, 2009


Landscape use and biophysical conditions define sediment status; sediment role depends upon endpoint under consideration


Fine-GrainedSoil/

Sediment

Fine Bed

Coarse Bed

Water Column

Estuaries

Mudflats

Coastal Floodplain

UplandFloodplain

Wetlands

River and NavChannel/Bank

Lakes, Ponds, Reservoirs

Salmonids/cyprinids

Column Feeding Fish

BottomFeeding Fish

InvertebratesCoarse Bed

InvertebratesFine Bed

DiatomsCoarse Bed

DiatomsFine Bed

MacrophytesCoarse Bed

MacrophytesFine Bed

Waterfowl

Fisheries

Supporting/Regulating

1˚ Production

Stabilization/Habitat maintenance

Provisioning/game

Cultural/ Recreation

Fine-grained sediment pathways:Biotic endpoints


WaterQuality

WaterConveyanceand Storage

In Water/Bank

Structures

Navigation

Flood Defence/Coastal Defence

BuriedContaminants,

Artefacts,Stratigraphy,

Fossils

Fine Bed

Coarse Bed

Water Column

Estuaries

Mudflats

Coastal Floodplain

UplandFloodplain

Wetlands

River and NavChannel/Bank

Lakes, Ponds, Reservoirs

Fine-GrainedSoil/

Sediment

Provisioning/Water

Regulating/ floodControl; stabilization

Resource access/ Transport

Regulating/Waste Control

Cultural/ Archival

Pathways for abiotic endpoints – fine-grained sediment

Sediment-Ecosystem Regional Assessment (SEcoRA) is the process

of characterising these complex interactions to inform decisions

We manage the landscape (on land

and in water) to optimize chosen

ecosystem services...

This affects the status of water, soils and

sediments at sites and in downstream

systems...

Ultimately, this affects the viability and sustainability of a variety of

aquatic ecosystem services

Watershed image from Natural Resources Conservation ServiceFrom S E Apitz (submitted) Beyond Habitat: Conceptualising the role of sediment in sustaining ecosystem services

This must be assessed and managed in a

spatially explicit manner


Adapted from *Colnar, A.M. and Landis, W.G., 2007.

Management of River Basin Objectives Requires Evaluation at the catchment, reach and field scale

Catchmenthierarchical patch

dynamics paradigm (HPDP)* approaches

can be used to address multi-scale interactions


The Sediment Regional Risk Model is a systematic framework for addressing the multi-scale interactions between land and water

management and their impacts on ecological and socioeconomic endpoints in watersheds

The model can either rank current risk pathways or predict the effects of

changes in management practices


Both intrinsic landscape properties and management activities (service use practices) affect sediment status

Non-agricultural land and water uses

Navigation is a source of impact, a driver of exposure, as well as an endpoint

impacted by other activities


Sediment status as a

result of land use can be

modelled using site-specific or probabilistic conditions

*From S E Apitz, S Casper, A Angus and S M White (2010) The Sediment Relative Risk Model (SC080018) – A User’s Guide.

© 2012 Sabine E Apitz *From S E Apitz, S Casper, A Angus and S M White (2010) The Sediment Relative Risk Model (SC080018) – A User’s Guide.

Land Use-Specific Modules Can be

UsedTo Model Sediment

Impacts


The ability of rivers to maintain sediment balance is driven by landscape conditions and management, including dredging

Exposure is driven by river

dynamics*From S E Apitz, S Casper, A Angus and S M White (2010) The Sediment Relative Risk Model (SC080018) – A User’s Guide.


Example of Model Outputs: Cumulative Risks to Endpoints, Upstream to Coast

Endpoints: SC-salmonids/cyprinids; CFF-column feeding fish; BF-Bottom feeding fish; IF-Invertebrates/fine; IC-invertebrates/coarse; D-benthic diatoms; M-macrophytes; WF-waterfowl; WQ-water quality; NV-navigation; CD-Coastal defence; WS-Water storage capacity; WCC-Water conveyance capacity; MG4-MG4 plants; P-Property; CS-compliant sediments

Upstream

Coast


Cumulative Risks from Sources, All Risk Regions


In terms of within-region sources, agriculturedominates in RRs C-FPoint sources and other land uses dominate in RR AHistorical wastes(identified point sources) in RRs A and BThere is an increasing risk from sources transferred from one region to the next downstream (Upstream Inputs)

Sources: AAn-Agriculture/animals; AAr-Agriculture/Arable; AOAr-Organic Agriculture/arable; AOAn-Organic Agriculture/Animals; ML-Moorland; WF-Woodland/Forestry; OL-other land uses; UL-urban landscape; HW-Historical waste sites; MQ-mining and quarrying; NUR-Non-urban roads; CSO-combined sewage outflows; SWT-sewage treatment works; I-industry; ICS-in-channel structures; BE-Bank erosion; UI-Upstream inputs


The step-by-step application of SRRM allows for a systematic, transparent and consistent approach to

addressing complex interactions – generating testable hypotheses about sediment sources and impact

pathways

©Sabine E Apitz, 2012

ConclusionsSediment plays a complex role in ecosystem functioning and the provision of ecosystem servicesLandscape biophysical conditions and managementpractices throughout a watershed must be considered to sustain ecological and socioeconomic objectivesNavigation and dredging practices affect stressor release, exposure but are also endpoints to be protectedCatchment or sediment management plans must balance the benefits of landscape-scale service use against the sustainability of aquatic ecosystem servicesTools are being developed to aid in such work


For more information...S E Apitz (2011) Conceptualising the role of sediment in sustaining ecosystem services: Sediment-Ecosystem Regional Assessment (SEcoRA), Science of the Total Environment, 415:9-30P von der Ohe, S E Apitz, M Beketov, D Borchardt, D de Zwart, W Goedkoop, M Hein, S Hellsten, D Hering, B J Kefford, A Marcomini, V Panov, L Posthuma, R B Schäfer, E Semenzin and W Brack (in press). Chapter 3. Risk Assessment to Support River Basin Management in J Brils, D Barcelo, W Brack, D Mueller, P Negrel, T Track, J Vermaat (eds), Towards Risk-Based Management of River Basins, Handbook of Environmental Chemistry Series, Springer.S E Apitz, S Casper, A Angus and S M White (2010) The Sediment Relative Risk Model (SC080018) – A User’s Guide. Report to the Environment Agency, SEA Environmental Decisions Ltd and Cranfield University, March 2010 (175p supplemented with a PowerPoint Guide).

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Sustainable Dredged Material Management? Tools and ...€¦ · sustaining ecosystem services: Sediment-Ecosystem Regional Assessment (SEcoRA), Science of the Total Environment, 415:9-30