Dredging Aberdeen HarbourA Presentation to the Scottish branch of the
Hydrographic SocietyBy Eddie Aitken
Hydrographic SurveyorAberdeen Harbour Board
Synopsis
Heading Sub-heading DescriptionOverview Need Deepening New Berths - Siltation
Types Capital - MaintenancePlant Examples
Preparation Surveying Hydrographic Surveying at Aberdeen Harbour (short presentation)Survey Data - Volumes
Schedule Plan of working areas - Schedule of work - MethodConsents SOAEFD - Crown Estates - DETR
Controls Contract ICE 7th EditionPre-Contract Documentation and Info
Management Supervision Bathy-Survey updates - Routine inspections - FRS samples - Logs - Forward planning
Quality Control Survey and Logs Bar Sweeps - Side Scan Sonar Surveys - Post Dredge - Correlation with Nav. Control Logs
Considerations Environment Vessel Traffic - Noise - Local Fishermen - Water Framework Directive
Dredging Aberdeen Harbour (Presentation to the Scottish branch of the Hydrographic Society)
Why do we dredge ?
1. To deepen areas following new quay construction or strengthening to accommodate deeper drafted vessels
2. To remove siltation and debris thus maintain the working depth
3. To create catchment areas to aid future dredging
Types of Dredging
1. Capital Dredging – New work, following a quay construction or to create a catchment. Usually carried out by a more powerful dredger such as a Backhoe, Bucket or Cutter Suction Dredger
2. Maintenance Dredging – To remove build up over a previously established level. Usually carried out by a Trailing Suction Hopper Dredger in cooperation with a Bed Levelling Tug or alternatively in confined areas by a Grab Hopper Dredger.
Dredging PlantTrailing Suction Hopper Dredger
Bed Levelling and Raking Tug
Grab Hopper Dredger
Spud Pontoon Mounted, backhoe Dredger
Trailing Suction Hopper
Dredgers
Trailing Suction Hopper
Dredgers
Bed Levelling
Tugs
Bed Levelling and Raking Boxes
Backhoe Dredgers
Bucket Dredgers
Grab Hopper Dredgers
Grab Hopper Dredgers
al
in
the
192
Rock Removal in the 1920’s
Blasting
ing
And
Blast
Rock DrillingAnd Blasting
Planning
• Tender/Pre Dredge Survey• Volumes Calculated Above the Designed
Bed Levels• Plan Showing Dredge Areas• Schedule Detailing Volumes and loads• Method Statement Detailing the Order of
Work• Disposal Licences and Consents
Hydrographic Survey Work
• Bathymetry• Side Scan Sonar• Lead Line Profiles• Bar Sweeps
Volumes Shown In 3D Pre, Post Dredge and the
Difference
Plan Showing Dredge Areas, Loads to be removed and the Schedule
Schedule Detailing Volumes and loads based on previous records
Pre Dredge Digital Terrain Model (TIN)
Method Statement• First areas to be dredged are the River Dee berths.• Second priority given to the deep water berths, Telford Dock
initially.• Third priority given to the remaining berths.
• Final areas to be the Navigation Channel, Tidal Harbour and approaches.
Disposal Licences and ConsentsFisheries Research Services (Agency for the SOAEFD)
Crown Estates Commissioners
Scottish Executive, Development Department, Transport Division 4
Annual Application (FEP1 form and BPEO Report) for a Licence to deposit dredge material at the established spoil ground under the ;FOOD AND ENVIRONMENT PROTECTION ACT 1985 PART II DEPOSITS AT SEA (AS AMENDED)
Decennial letter of application to deposit material on crown seabed
Application for 6 Yearly consent for Disposal of Dredgings from Aberdeen Harbour under Section 34 of the Coastal Protection Act 1949 as amended by the Merchant Shipping Act 1988.
Controls
• ICE Conditions of Contract 7th Edition with additional Special Conditions
• Pre-Contract Documentation• Work Permit
Additional Clauses to ICE Contract ConditionsClause 73 Variation of Price No variation over contract term
Clause 74 Harbour Regulations Adherence to Bye-laws and Pilotage Act 1997
Clause 75 Weather and Tide Delays At the Contractor's expense
Clause 76 Dumping Ground Location and Ref. To Admiralty Chart
Clause 77 Dredging Returns Direction to have them completed and submitted
Clause 78 Demurrage Advise as to expected delays and use of stand-by rate
Clause 79 Disturbance Dredging - Spillage Directions to minimise spillage
Clause 80 Measurement for purposes of Payment Description of the measurement method
Clause 81 Contractor's Staff and Equipment Full time agent and if necessary a hydrographic surveyor
Clause 82 Access to Dredging Plant Access provision for spot checks
Clause 83 Dumping Licence Advise on adherence to the disposal licence
Clause 84 Income Tax Prior to commencement of the works the Sub-Contractors Tax Exemption Certificate CIS 5 or 6 must be issued
Clause 85 VAT Receipt Prompt return of VAT receipt on payment
Clause 86 Performance Details of expected standard of performance
Pre-Contract DocumentationIssued by Contractor Issued by Client
•Copies of disposal license
•Paper Chart copies
•Emergency contact list
•Copy of Aberdeen tide tables
•Fisheries Research Services (FEP6) disposal log form
•Latest Port handbook
•Copy of Hopper Ullage Tables
•Letter Covering CIS5,6 Income Tax Clause 84
•Company Safety Policy
•Contract Safety Plan and Risk Assessment
•Copy of Insurances
•Copy of Master's Documentation
Other considerationsVehicle details from contractor for security clearance
FRS sample jars issued for sampling throughout the works
Organise debris skip to Mearns Quay East
Draw the contractor’s attention to the Vessel Transportation Plan and Marine Mammal Recording Form at the rear of the disposal licence
Inform local fishermen that the dredger is to commence as they often lay creels or nets around the spoil ground
International Ship and Port Facility Security (ISPS) Code must be faxed or emailed to Port Control before dredger enters port if arriving from outside the UK.
Aberdeen Harbour Work Permit
•Gives emergency contact telephone number.•Gives recommended standards for health and safety.•Serves as a security pass for access to working areas.•Gives brief details on safe working procedures.•Only issued when all other documents relative to the works have been exchanged
Supervision•Survey updates
•Routine inspections
•Logs
•FRS Samples
•Forward planning
•Spot Checks and log correlation
Survey UpdatesSurvey Updates
Routine Inspections
Routine Inspections
ABERDEEN HARBOUR BOARD
DAILY DREDGING RETURNTo be completed daily by the Contractor's Superintendent and returned to theHarbour Engineer before 9:30am on the second day following the 24 Hourperiod that this form describes
Date 12/05/2005 TSHD Amazone
Working Area's of Dredger Telford TelfordTelfordTelford
Measured Quantities (Hopper M3)1405 8541077983
Total = 4319
Total Time Dredging: 245In Minutes Sailing: 235
Dumping: 20DelaysStop Time Start Time Total Time Description of Delay
16:25 16:35 1017:10 17:15 518:00 18:10 1018:50 19:05 1519:30 19:40 1020:40 21:00 2021:25 21:30 521:50 22:00 1022:10 22:15 523:20 23:30 1023:55 00:00 5
Total of Delays and operational 605hours should equal 24hours(1440Mins)
Signed ............................................................................…(Contractor's Superintendent)
NB: If the contractor should encounter any obstructions to dredging he should notify the Engineer's Representative immediatly.
Cleaning draghead
Cleaning dragheadWaiting for outgoing shipCleaning dragheadCleaning draghead
Cleaning dragheadWaiting for outgoing ship Malyvia 19Waiting for outgoing ship HascosayCleaning draghead
Waiting for outgoing fishing vesselAll fast alongside Clipper Quay for repairs bowthruster.
Daily Dredge Return
Load Number Ladingnummer 1 2 3 4 5 5
Dredge Area Baggervak Telford Telford Telford Telford
Hopper Soundings (M) HoppermetingenPort/Starboard Fore 880.00 900.00 890.00 865.00 865.00 870.00 860.00 870.00
Mid 885.00 855.00 875.00 880.00 870.00 850.00 865.00 855.00
Aft 800.00 880.00 870.00 875.00 860.00 870.00 825.00 870.00
Average 866.67 875.83 864.17 857.50
Sluice Level (M) Meting vloeistofoppervlak 155.00 170.00 145.00 140.00
Gross Hopper Volume (M3) Volume hopper totaal 2371 2321 2404 2420
Volume of Settled Solids (M3) Volume vaste stof 71 60 74 83
Volume of Liquid (M3) Volume vloeistof =(totaal - vast) 2300 2261 2330 2337
Measured % Solids in Suspension Percentage monster 58% 45% 39% 33%
Bulk Volume of Solids in Suspension (M3) Vaste stof in mengsel (% x Volume)Total Volume of Hopper Solids (M3) Totaal vaste stof (hopper + mengsel)Start Loading Time 13:55 16:00 18:30 21:15
Finish Loading Time GELE VLAKKEN NIET INVULLEN 14:55 17:10 19:55 22:40
Dump Start Time 15:30 17:45 20:25 23:05
Dump Finish Time 15:35 17:50 20:30 23:10
Co-ordinates at Dump StartCo-ordinates at Dump Finish
771
1077 983 8541405
1334 1017 909
Daily Dredge Load Sheet
Navigation Control logs all vessel movements
FRS Marine Mammal Recording Form
FRS Samples and Visits
FRS Samples and Visits
Forward PlanningForward Planning
Quality Control• Pre, interim and post-dredge bathymetry• Side Scan Sonar surveys• Bar sweeps• Leadline profiles at quaysides• Correlation with port control vessel movement logs• In-situ comparison against hopper volumes• Log of vessel track to spoil ground• Visual check of disposal vessel from shore of dumping location.• Inspection of samples, sluice adjustment, communication with AHB Port Control, independent hopper
dip measurement, positioning system accuracy, water jet and degassing use (suction dredger)• Post contract report
Form FEP4 Fisheries Research Services (FRS) Environmental Protection Section, Marine Laboratory, PO Box 101 Telephone No: 01224 295331 Victoria Road, Torry Switchboard: 01224 876544 Aberdeen AB11 9DB Facsimile: 01224 295524
FOOD AND ENVIRONMENT PROTECTION ACT 1985 PART II DEPOSITS AT SEA (AS AMENDED)
SECTION 14 AND SCHEDULE 4
LICENCE RETURN FORM FOR THE DEPOSIT OF SOLID WASTE (E.G. DREDGE SPOIL)
IN THE SEA NOTES: 1. This form must be completed as a condition of licence. 2. The form must be completed in full, detailing NIL returns if appropriate. 3. The completed form must be submitted to the above address. A copy should be retained for your own records. 4. The licence conditions detail the required frequency of licence returns. 1. FRS Reference Number: D26 2. Licence Number (including revisions) : 1881 (Rev 3) 3. Licence Validity Dates: 7 January 2003 to 7th January 2004 3.1 Commencement and Completion Dates of Operations: 4. Name of Licensee: Aberdeen Harbour Board 5. Name of Sea Disposal Contractor(s) 1. WD Medway II, Westminster Dredging and Vessel(s) 2. WD Medway II, Westminster Dredging 3. Cherry Sand, UK Dredging 4 Cherry Sand, UK Dredging 6. General Description of Waste: Silt, Sand, Clay, Gravel and Cobbles 7.Geographical Coordinates of Disposal Site(s) 57° 07’ N 02º 00’ W 8. Nature and Quantities of all Materials Deposited below Mean High Water Springs (in cubic metres and tonnes):* *Continue on a separate sheet if necessary Signed ................................................................... For and behalf of the licensee Date ......................................................................
1 19/01/2003- 23/01/2003 2 18/05/2003- 29/05/2003 3 29/08/2003- 27/09/2003 4 29/08/2003- 27/09/2003
1. 12,047 M³, 15,661T Maintenance 2. 122,876 M³,159,739T Maintenance 3. 4,738 M³, 9,476T Capital 4. 28,260 M³, 36,738T Maintenance Total Capital 4,738M³, 9,476T (insitu vol) Total Maintenance 163,183M³, 212,138T (bulked vol)
FRS FEP4 Return
Environment
• Vessel Traffic• Noise• Local Fishermen• Water Framework Directive
Questions?