6th Meeting of the NSHC Re-survey Working Group

published at NSHC, Resurvey Working Group | 0


Rostock, 10-11 November 2016


Mrs. Virginie Debuck (BEHO)

Mr. Bernd Vahrenkamp (BSH)

Mr. Jesper Vedel and Mr. Lars Hensen (DKHO)

Mr. Eric Langois (SHOM)

Mr. Leendert Dorst (chairman) and LT Raymon van de Veen (minutes) (NLHO)

Mr. Simon Bicknese (observer) (RWS)

Mr. Ulf Olsson (SMA)

Mr. Phil Payne, Mrs. Ruth Waters and Mr. Jeffrey Worth (UKHO)

Mrs. Paula English (observer) and Mr. Bob Kinnear (observer) (MCA)

1. Welcome and opening formalities

The chairman opens the meeting at 16.10. A special thanks to the BSH for hosting this meeting and hosting the dinner. Also a special welcome to new attendees. The minutes of the 5th meeting are accepted without changes. The draft agenda is accepted without further changes.

Status of action items:

Item 1: provide updated input to the overview of resurvey schemes (resurvey plan, quality). This item is ongoing. When changes are made to the resurvey plans of MS, MS are requested to send updates of their plan to the BSH so North Sea overview map can be updated.

Item 2: Collect the information from MS and build the GIS-files and process combined overviews based on ArcGIS. The updated scheme will be handed over to all MS. BSH has been working on creating a North Sea Bathymetric Database, which is part of the new NSHC website. BSH will continue with this action item when updates are received from MS.

Item 3: Provide the data for a publication of the overview on the internet. BSH will continue on this item following input from item 1.

Item 4: Each MS implements a link to the overview or publishes the overview on their website. Depending on the progress of items 1, 2 and 3 will this be done. None of the MS has done it so far. UK doesn’t have a resurvey plan for the North sea. They will have an internal discussion to see if it is possible to publish some sort of resurvey scheme.

Item 5: Draft Terms of Reference. DKHO has completed this task. The ToR are accepted. Deleted from action list.

Item 6: Draft answer to NSHC about the applicability of alternative survey techniques. NLHO and SHOM have worked on this. The final document has been discussed at the NSHC conference in Amsterdam. Deleted from action list.

Item 7: Write paper for HSSC on the usage of S-44 standard. All MS are requested to give input. Completed. Item deleted from action list.

Item 8: Inform MS on progress of SMARTSEA project. Discussed at agenda item 3. Completed

Item 9: Deliver Technical Hydrographic Instructions for the Dover Strait Survey Strategy Agreement, or a new version. UK and FR will provide new Technical Hydrographic Instructions.

Item 10:Give input to new DSSS Agreement. Overtaken by events. Pertinent parts of the DSSS agreement will be incorporated in the ToR of the RWG. Item closed

Item 11:Draft a new DSSS Agreement. Overtaken by events, see item 10. Item closed

Item 12: Give input to chairman on the value of a North Sea wide risk assessment, as well as its limitations. Input received from DK and UK. Item closed.

Item 13:Write paper for NSHC to answer the dedicated task of a North Sea wide risk assessment. Completed. Item closed.

Item 14: Write letter to inform NSHC members on MARID conference 4-6th April 2016. No input received. FR will report about the main findings by correspondence.

2. Update on NSHC and EU developments since the 5th meeting

The chair provided an overview of relevant parts of the NSHC32 minutes. No further questions or remarks from MS.

DE gives an overview on the new features on the NSHC website. NL askes about the intended target audience. The website is intended for all that are interested in the work of the NSHC and its WGs. DE intends to create a login protected part of the site so it is easier to exchange documents between MS (action 15). UK asked if the amount of visitors on the website is monitored? DE will report on the amount of visitors during upcoming meetings (action 16) and update the website with links to the INSPIRE portals of MS (action 17).

DE shows the new bathymetric datamodel of the North Sea Bathymetric Database (NSBD). This model is created using the provided data from MS complemented with data from EMODNet. At the moment it is only possible to read the value of one cell and show the data in 3d. There is no download option available.

The status of the EMODNet Coastal mapping project, EMODNet Bathymetry project, and the future EMODNet High Resolution Seabed Mapping (HRSM) project are discussed. The chair explains the interconnection of the projects and gives an outlook. The RWG will adopt a passive role for these projects: it will serve as a place to discuss progress in the online availability of bathymetric data, but it will not actively manage the NSBD. If awarded to the consortium of hydrographic offices, DE will coordinate the collection of the data for the HRSM project through the NSBD as a project partner.

post meeting note: EMODNet HRSM has been awarded to the consortium of hydrographic offices on 28 November 2016.

FR will report on the outcome of the MARID conference during next meeting (action 9 refers).

3. Update of national developments

BE reports that there is no news on the ‘Interpretation of order 1a vs order 1b”.

BE has not yet decided on “How to define the ‘most un-deep value’”. UK invites BE to UKHO offices to show and discuss how UK maps the ‘most un-deep value’. A discussion followed on the most suitable value to be selected during the gridding process. DK charts the shoalest sounding because of the presence of rocks in their waters, the UK process depends on the area of survey. UK mentioned that they have a paper on which value to use based on bottom structure. MS are invited to provide input on what value to use in which situation (action 18). The UK paper will be used as a base for this document (action 19). RWS mentioned that at the end of 2016 Delft University of Technology will have a report available on a similar project.

BE is working on a priority plan for the Belgian waters. They expect this plan to be ready halfway 2017. Based on this priority plan they will make a resurvey plan. BE mentioned that they will have a new survey vessel “Sirius” available in 2017. This vessel will be used by multiple parties.

DE updated their resurvey plan. Changes are in the coastal area and harbour approaches. DE implemented many restricted areas on the German continental shelf because of planned wind farms.

DK Geodata Agency is relocated and lost around 80% of their experienced personnel.

DK philosophy for the deeper areas of the Danish part of the North Sea is to survey the area once and then monitor if the area is changing and then decide if it is necessary to resurvey the area. The entrances to harbours will be surveyed after every major storm because of the mobility of the seabed. DE has surveyed a part of the DK waters around the maritime boundary.

FR has just decided on a new survey plan for the period 2017-2019. FR will send this plan to DE (action 1 refers) so it can be implemented in the overview published on the NSHC RWG website (action 2 and 3 refer). FR will perform some dune control and wind farm surveys in the Dover Strait area in 2017-2018.

FR will implement the CATZOC instead of referring to the date of a survey. UK comments that one has to combine the date of survey with the CATZOC because the CATZOC is intended to change over time.

NL gives an update on the SMARTSEA project (action 8 refers) with a presentation received from the project team.

NL gives a short presentation on the change of their resurvey scheme in the Southern North Sea. Also, the survey plan for 2017 is presented. An update of the resurvey plan will be send to DE (action 1 refers).

SE will continue their long term survey plan (2010-2020). When finished with this plan a new survey plan will be made. At the moment, areas with mobile seabed and critical draught areas ae surveyed every 3-4 years.

SE is working together with BSHC MS to develop a common reference surface for the Baltic Sea region.

UK gives an update of their survey plan for 2017. Areas with mobile seabed and where UKC is critical are surveyed on a regular basis. Because UK has limited resources to survey the national UK waters, a risk based approach is used to decide on where to survey. After a survey is performed, it will be decided if the resurvey interval is still valid. UK will share a link to a report on this topic with all MS (action 20).

4. Applicability of alternative survey techniques

SDB: UK has published its first charts with satellite derived bathymetry (SDB). Before publishing these charts, a thorough investigation was performed with overlapping MBES data to decide if SDB is accurate enough for publication and if so, until what depth. Areas mapped with SDB are given a CATZOC “C” value. UK mentioned that SDB is not useful in the North Sea areas, because the water is not clear enough.

DK asked if the report can be shared with the other MS. UK will share the report (action 21).

FR is using SDB and they are comparing SDB data with MBES data. FR is also investigating if stacked images give a better result than single images.

CSB: DE mentioned that the Crowd Sourced Bathymetry (CSB) working group that came together earlier this week released a guidance document on how they think CSB can be used. Equipment and instructions need to be put out to non-survey vessels and companies. UK asked who will fund this plans. This is not known.

LIDAR: UK is investigating if LIDAR can be used in the North Sea area.

FR plans to perform a LIDAR survey in the Normandy region (pending funds).

18.45 end day 1. DK and SE join the BSHC resurvey Monitoring WG

11 Nov 2016 08.50: chair opens second day of meeting

5. Termination of BE/FR/NL/UK Dover Strait Survey Agreement

The chair provides some background information on the the RWG and the DSSS Agreement.

Publication of Technical Hydrographic Instructions (THIs): UK, BE, NL and FR all have provided THIs. The chair will distribute the received THIs among the MS. (action 22). FR is translating its THIs. MS will provide changed THIs before they will be published on the website (action 23). Corrections should be handed in before the 31st of December 2016. DE will provide THIs as well (action 9 refers).

Transfer of the pertinent items in the Agreement to the Terms of Reference (ToRs) and Rules of Procedure (RoPs): The chair provided a draft version of the new ToRs and RoPs of the NSHC RWG, including the pertinent parts of the DSSS Agreement. MS have a short discussion about the new ToRs. MS proposed some small changes in paragraph 1.1. Paragraph 2.8 changed to “Changes in THI will be discussed….” Small change in introduction, “…Deep draught vessel passing through the North Sea…”

MS will discuss further at national level, to be prepared for NSHC request for approval . Chair will submit the changed draft to Chair NSHC (IE) (action 24).

Termination of DSSS Agreement: UK states that it might be wise to agree upon the new ToRs and RoPs before terminating the Agreement. The chair states that that could delay the process. It is decided to proceed on the termination. NL has drafted a termination letter. After some discussion, it is decided that all four parties will sign a single declaration, instead of a letter per party. NL will change the draft letter (action 25), sign and submit the new version to the other parties, who will do the same (action 26).

6. Towards a Dover Strait wide risk assessment

This agenda item consist of 3 parts, introduced in the document “towards a common risk assessment framework for the North Sea – or Not”.

Part 1: each MS has its own survey strategy, based on the physics of its part of the North Sea, the particularities of usage, and its own capacities: exchange of national survey strategies is current practicce within the RWG, no further actions necessary.

Part 2: verify the consistency of the national strategies: MS agree that it is currently not possible to create a risk assessment for the entire North Sea area using all data sets mentioned in the paper. Decided is that the considered area is limited to the Dover Strait area, like NHSC already decided for part 3, plus the areas where the Selected Track for deep draught ships is located outside of the Dover Strait area (Southwestern part of the Netherlands waters and the relevant parts of the English Channel/La Manche).

BE, FR, NL and UK agree to provide information on survey status (applied S-44 order; date of last survey; applied sensors) (action 27). Depth has already been provided, and seabed mobility will be provided at a later stage. AIS data (shipping intensity and maximum draught) should be obtained from third parties, at a later stage. Administrative and usage areas are available through EMODNet Human Activities.

Information exchanged will be in shape format (in WGS84 or ETRS89). DE will create overview maps from the provided data sets (action 28). It will be easiest to share the data through web services (like WMS and WFS), if available, to guarantee that the shown data remains up-to-date.

10.10 – 10.30 coffee break and photo with BSHC RWG

Part 3: undertake an analysis in line with recent developments: UK states that it is important to specify the risk assessment question in detail before work starts. The risk to be described is the risk to SOLAS navigation due to limits to the quality of charts and other nautical publications. Important is that a common understanding is developed, based om traffic, morphological behaviour and hydrodynamic aspects. BE, FR, NL and UK will provide examples of national projects on risk assessment and used data types (action 29) . FR will combine the input into a list (action 30).

All MS will discuss at national level what the end product should look like (action 31). NL will distribute the abstract from the “LINZ study” again (action 32). A simple method to combine the input data sets into a risk map could be “expert judgment”, where the working group creates a common risk map based on a shared interpretation that follows from experience.

7. Any other Business

No further subjects were discussed.

8. Closing formalities and farewell

Mr. Leendert Dorst introduces the new chair Mrs. Ruth Waters (UK). The next meeting will take place before NSHC33 in March 2018, probably early November 2017 in London.

9. Common session with BSHC Resurvey Working Group

After lunch a common session with the BSHC Resurvey Monitoring WG was held to inform both working groups on issues discussed during the individual meetings.

Action List


Action item




Provide updated input to the overview of resurvey schemes

  • Resurvey plan
  • quality




Collect the information from MS and build the GIS-files and process combined overviews based on ArcGIS. The updated scheme will handed over to all MS


ongoing, depending on 1


Provide the data for a publication of the overview on the internet.


ongoing, depending on 2


Each MS implements a link to the overview or publishes the overview on their website


depending on 3


Inform MS on progress of SMARTSEA project




Deliver updates to the Technical Hydrographic Instructions,

(status of 31-12-2016 will be published on web site)




Give input to new DSSS Agreement


overtaken by events


Draft a new DSSS Agreement


overtaken by events


Give input to chairman on the value of a North Sea wide risk assessment, as well as its limitations




Write paper for NSHC to answer the dedicated taks of performing a North Sea wide risk assessment




Inform MS on MARID conference 4-6th April 2016




Create a password protected area within the NSHC website





Report on the number of visitors on the NSHC website




Update the website with links to the INSPIRE portals of MS

DE, assisted by MS



Provide input on “what depth value to use for gridding in which situation”




Distribute paper “what depth value to use for gridding in which situation”





Share link to paper “check on resurvey interval” with MS





Share “report on SDB vs MBES” with MS





Distribute received THIs among MS


completed 17-11-2016


Publish THIs on web site





Send new draft ToRs and RoPs to NSHC chair (IE)





Change “DSSS termination letter” and send it to the parties





Sign DSSS Agreement termination declaration




Provide data sets of S44 order, applied sensors and date of last survey from Dover Strait area





Create maps of the provided data sets





provide examples of national projects on risk assessment and used data types





combine the input for the risk assessment question into a list





Discuss a national level what the outcome of the risk assessment for the Dover Strait area should look like.




Distribute abstract from “LINZ study” as input for risk assessment