Estuaries, Sediments and Dredging

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1 Estuaries, Sediments and Dredging Professor Mike Elliott Institute of Estuarine & Coastal Studies, University of Hull

2 Antony et al., 2009, Ecol. & Society

3 Regions of an estuary (e.g. Forth Estuary, Scotland) Tidal limit Tidal Freshwater Area (TFA) Head of Estuary Freshwater Seawater Interface (FSI) Upper estuary Turbidity Maximum Zone Middle Estuary Lower Estuary Estuary Mouth Estuary limit Firth of Forth

4 The upper estuarine areas TFA, FSI and TMZ

5 global position temperature regime water mixing density regime stratification water run-off O 2 regime residence time climate wind regime hydrological regime Water-column fundamental niche water input salinity regime nutrient regime Coriolis tidal regime ph regime photic zone wave regime water current strength erosion-deposition cycles physiography geomorphology turbidity regime light regime colour regime mineral inputs sediment supply tectonics underlying geology ph, salinity regime substratum gas, hydrothermal seeps chemosynthesis exposure regime Substratum fundamental niche depth regime

6 Hydroclimagraphs - for the Upper Forth Estuary

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8 Sedimentary interrelationships (from Elliott et al 1998 (UK Marine SAC Project on e.g. fine cohesive and poorlysorted sediments in low energy areas, small average particle size, created under low flow conditions, giving high amounts of silt & clay and organic matter (and often contaminants), poor oxygen and so anoxic conditions.

9 Sedimentary interrelationships Between current speed, particle size, erosion, transport and deposition. (Stowe, 1996)

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

11 Marine/Estuarine Community Forcing Variables Physicochemical attributes Fundamental niche biol.-env. links env.-biol. links Community functional attributes biol.-biol. links Community structural attributes

12 Benthos 3-D structure and functional groupings (From Reise (1991) in Elliott & Ducrotoy (1991))

13 Bird and fish food!

14 Normal seabed organisms - many species, all sizes Polluted seabed community - few species, small organisms

15 Seabed community types and species richness along estuary-marine continuum (Elliott & Kingston 1987)

16 Organisms modifying sediments

17 Estuaries as a major overwinter feeding areas for wading birds and feeding and refuge areas for fishes

18 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

19 bait digging - manual continuous wave and shore processes bait digging - mechanical methods pipeline construction Spatial extent of intertidal bioturbation foraging / micro disturbance by wader foot prints and beak activity beach nourishment - trickle charging extreme wave and tidal events beach nourishment - dumping and mechanical placement Large Small Low Intensity of disturbance on intertidal flats High Spatial and temporal changes to sediments (Elliott et al. 1998; 2001)

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

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

22 Dredging and dredged-material disposal

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

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26 Trailing suction hopper dredger

27 Port bell-mouth dredging and disposal

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30 Unhealthy systems? Medical ( *1 ) Diagnosis Prognosis Treatment Recovery Prevention (*1 Steevens et al Human Ecol. Risk Ass.) Environmental Assessment (*2) Prediction Remediation/Creation/ Restoration Prevention (* 2 using extension of symptoms for the diagnosis of ecosystem pathology) Comparison of the health of medical and environmental systems (modified from Elliott & Cutts 2004; see Tett et al., MEPS 2013)

31 Challenges for science & management: 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. 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

32 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, 3 rd 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')

33 International Law / Commitments KEY Marine environmental protection International Bodies & Conventions T reatment of urban waste water Quality of bathing waters Renewable energy targets Nitrates & fertiliser control Regulations to control shipping & pollution from ships to give safer shipping, navigation and pollution control and operation Integrated pollution control Control of waste Strategy and regulations on invasive alien species control LONDON CONVENTION & PROTOCOL U.N. FRAMEWORK CONVENTION ON CLIMATE CHANGE (UNFCCC) KYOTO PROTOCOL Inshore fisheries management 0-6nm BALLAST WATER CONVENTION ESPOO CONVENTION IMO MARPOL INTERNATIONAL CONVENTION ON SALVAGE Management of fisheries from 6nm to 200nm for sustainable fisheries ICES UNCLOS BERN CONVENTION CITES OSPAR, HELCOM, UNEP-MAP, BUCHAREST (Regional Seas Conventions) UNESCO PROTECTION OF UNDERWATER CULTURAL HERITAGE U.N. CONVENTION on BIOLOGICAL DIVERSITY Safe consumption of shellfish and fish RAMSAR CONVENTION Flood and coastal erosion protection BONN CONVENTION T ransitional and coastal waters status Coastal and marine waters status Environmental liability to prevent and remedy environmental damage Integrated maritime policy Marine spatial planning (MSP) & coastal zone management (CZM) Biodiversity strategy Protection of wild birds in transitional, coastal and marine waters Protection of habitats & species in transitional, coastal and marine waters Strategic assessment of public plans or projects in a transboundary effect Impact assessment of a plan or project Protection of marine archaeology CIT ES fauna & flora for endangered species protection (Boyes & Elliott MPB 2014)

34 Slufter/Papasbiek System for Contaminated Dredgings

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36 Professor Mike Elliott, Institute of Estuarine & Coastal Studies, University of Hull