Estuaries, Sediments and Dredging Professor Mike Elliott - - PowerPoint PPT Presentation

Estuaries, Sediments and Dredging

Professor Mike Elliott Mike.Elliott@hull.ac.uk Institute of Estuarine & Coastal Studies, University of Hull http://www.hull.ac.uk/iecs

Antony et al., 2009,

• Ecol. &

Society

Tidal Freshwater Area (TFA) Freshwater Seawater Interface (FSI) Turbidity Maximum Zone Upper estuary Firth of Forth Lower Estuary Estuary limit Tidal limit Head of Estuary Estuary Mouth Middle Estuary

Regions of an estuary (e.g. Forth Estuary, Scotland)

The upper estuarine areas – TFA, FSI and TMZ

global position underlying geology geomorphology tidal regime climate wind regime wave regime hydrological regime gas, hydro- thermal seeps sediment supply water current strength water input residence time physiography tectonics Coriolis salinity regime water mixing density regime depth regime exposure regime O2 regime pH regime erosion-deposition cycles chemosynthesis colour regime turbidity regime nutrient regime Substratum fundamental niche Water-column fundamental niche light regime pH, salinity regime mineral inputs water run-off temperature regime substratum photic zone stratification

Hydroclimagraphs - for the Upper Forth Estuary

Sedimentary inter- relationships

(from Elliott et al 1998 (UK Marine SAC Project on www.englishnature.gov.uk) e.g. fine cohesive and poorly- sorted sediments in low energy areas, small average particle size, created under low flow conditions, giving high amounts

• f silt & clay and organic matter

(and often contaminants), poor

• xygen and so anoxic conditions.

(Stowe, 1996) Sedimentary inter- relationships

Between current speed, particle size, erosion, transport and deposition.

Healthy estuarine mud – main message ‘look after the hydrography and the sediments, then the invertebrates and their predators will then be OK’

Physico- chemical attributes Fundamental niche Community functional attributes Community structural attributes env.-biol. links biol.-env. links biol.-biol. links Marine/Estuarine Community – Forcing Variables

Benthos 3-D structure and functional groupings

(From Reise (1991) in Elliott & Ducrotoy (1991))

Bird and fish food!

‘Normal’ seabed organisms

• many species, all sizes

Polluted seabed community - few species, small

• rganisms

Seabed community types and species richness along estuary-marine continuum

(Elliott & Kingston 1987)

Organisms modifying sediments

Estuaries as a major

• verwinter feeding areas

for wading birds and feeding and refuge areas for fishes

Erosion-Deposition Cycles in Estuaries

• 6-hourly – stronger currents on ebb and flood tide leading to

erosion, weaker currents at high and low slack water leading to deposition

• Daily – diurnal tides (2 tidal cycles per day but not equal

strength)

• Fortnightly – spring tide one week (stronger tides, more water

and greater currents, hence more erosion); neap tide other week (weaker tide, lower currents, more deposition

• Lunar – 2 spring and 2 neap but not equal strength
• Euinoctial – 6 monthly intervals, different tidal regime, hence

different strength

• Winter high flows down estuary pushing sediments seawards

and then tidal-dominated in low river conditions, allowing sediment pulsing back up the estuary

• Random events – storm surges, spates, pluvial and fluvial

flooding

Large Small Low High Intensity of disturbance on intertidal flats Spatial extent of intertidal extreme wave and tidal events pipeline construction beach nourishment - dumping and mechanical placement beach nourishment - trickle charging bait digging - mechanical methods bait digging - manual continuous wave and shore processes foraging / micro disturbance by wader foot prints and beak activity bioturbation

Spatial and temporal changes to sediments (Elliott et al. 1998; 2001)

Natural and anthropogenic accreting (depositing) areas (a)Natural bay (Inverkeithing Bay, Forth) (b)Burntisland Docks, Firth of Forth (a) (b)

Immingham (plus Hull, Goole, Grimsby) – Largest Ports Complex in UK

Dredging and dredged-material disposal

Humber Estuary - major trading route & ports (need dredging)

Trailing suction hopper dredger

Port bell-mouth dredging and disposal

Comparison of the health of medical and environmental systems (modified from Elliott & Cutts 2004; see Tett et al., MEPS 2013)

Unhealthy systems?

Medical

(

*1

) –

• Diagnosis
• Prognosis
• Treatment
• Recovery

Prevention

(*1 Steevens et al 2001

• Human Ecol. Risk Ass.)

Environmental –

• Assessment

(*2)

• Prediction
• Remediation/Creation/

Restoration

• Prevention

(* 2 using extension of symptoms for the diagnosis

• f ecosystem pathology)

Challenges for science & management:

• Recovery/coping with historical legacy
• Endangered coastal and marine ecosystem

functions

• Legal & adminstrative framework
• Economic prosperity and delivery of societal

benefits

• Coping with climate change & moving

baselines

There is only one big idea in estuarine and marine management: how to maintain and protect ecological structure and functioning while at the same time allowing the system to produce ecosystem services from which we derive societal benefits.

The Health & Integrity of the estuary: Environmental Quality Objectives

• 1. The protection of all of the existing defined uses of the

estuary system;

• 2. The ability to support on the mud bottom the biota

necessary for sustaining sea fisheries;

• 3. The ability to allow the passage of migratory fish at all

stages of the tide.

(Based on those proposed by Royal Commission on Environmental Pollution, 3rd report 1972)

(Define EQO, derive EQS, set consent conditions and discharge limits bearing in mind EU Directives, PARCOM, the 'precautionary principle and the Red list')

Treatment of urban waste water Quality of bathing waters Nitrates & fertiliser control Marine spatial planning (MSP) & coastal zone management (CZM) Renewable energy targets

U.N. CONVENTION on BIOLOGICAL DIVERSITY UNCLOS MARPOL

Regulations to control shipping & pollution from ships to give safer shipping, navigation and pollution control and

• peration

Integrated maritime policy

RAMSAR CONVENTION BERN CONVENTION BONN CONVENTION

Integrated pollution control Control of waste

LONDON CONVENTION & PROTOCOL OSPAR, HELCOM, UNEP-MAP, BUCHAREST (Regional Seas Conventions) BALLAST WATER CONVENTION

Management of fisheries from 6nm to 200nm for sustainable fisheries

ICES

Strategy and regulations on invasive alien species control Safe consumption of shellfish and fish Transitional and coastal waters status Environmental liability to prevent and remedy environmental damage Flood and coastal erosion protection Coastal and marine waters status CITES fauna & flora for endangered species protection

CITES

Protection of habitats & species in transitional, coastal and marine waters

U.N. FRAMEWORK CONVENTION ON CLIMATE CHANGE (UNFCCC) KYOTO PROTOCOL ESPOO CONVENTION

Strategic assessment of public plans or projects in a transboundary effect

IMO INTERNATIONAL CONVENTION ON SALVAGE

Impact assessment of a plan or project Protection of wild birds in transitional, coastal and marine waters Biodiversity strategy Inshore fisheries management 0-6nm Protection of marine archaeology

UNESCO PROTECTION OF UNDERWATER CULTURAL HERITAGE

Marine environmental protection

KEY

International Law / Commitments International Bodies & Conventions

(Boyes & Elliott MPB 2014)

Slufter/Papasbiek System for Contaminated Dredgings

Professor Mike Elliott, Institute

• f Estuarine & Coastal

Studies, University of Hull Mike.Elliott@hull.ac.uk, http://www.hull.ac.uk/iecs