Hydrographic Survey Management Guidelines
Table of Contents
- 1 Introduction
- 2 Hydrographic Survey Instructions
- 3 Survey Planning
- 4 Error management and equipment calibration
- 5 Mobilization
- 6 Data acquisition and processing
- 7 Quality control
- 8 Data rendering and submission
- 9 Reporting
- 10 Abbreviations, Acronyms, Definitions, and Terms
3 Survey Planning
Before leaving for the field, the HIC and his team will have to plan the work to be done, gather all pertinent information required to accomplish the various tasks and verify that all the equipment to be taken to the field is in proper working order and calibrated. In advance, ensure medicals are completed, pertinent risks identified and work procedures read/signed by employees, and all required training completed before tasks are taken on.
In some cases it may be desirable to visit the area prior to the actual survey to establish personal contacts, accommodations and temporary offices (if required) and gain some appreciation for the work area.
It is sometimes required to obtain authorizations to work in some areas such as parks, reserves, etc. In such cases, it may be required to consult the relevant authorities (Indian Affairs and Northern Development Canada, Parks Canada, etc.) to be well informed of good practices and keep good relations with these entities.
See CUBE Bathymetric data Processing and Analysis (CHS February 2012).
3.1 Data Representation
CHS has discontinued producing physical fieldsheet for hydrographic data.
The digital world has greatly altered the concept of scale. Digital hydrographic data can be represented at various scales for internal use. However, digital hydrographic data shall be submitted at the best possible resolution (refer to CUBE Bathymetric data Processing and Analysis (CHS February 2012)).
The codification of the data on a digital hydrographic dataset should be done according to the specifications found in the current version of the digital coding guide. This is to ensure proper representation of the features in the dataset.
Note that line spacing is no longer determined according to the scale of the survey but by the depth and the seabed characteristics of the sounding areas as determined by the survey order (see Table 1 of the CHS Standards for Hydrographic Surveys).
3.2 Survey order
The accuracy requirements for various areas to be surveyed are listed in CUBE Bathymetric data Processing and Analysis (CHS February 2012), Table 1 – Standards for Bathymetric Data, Table 2 – Standards for Positioning of Navigation Aids and Important Features, both found in the CHS Standards for Hydrographic Surveys.
The order to which the survey area will be surveyed must be determined prior to leaving for the field. This determination will dictate the accuracies, the bottom coverage, the line spacing and the required detection capability required for the acquisition of the bathymetric data.
Critical areas such as shallow water in harbours, berthing areas, and associated critical channels with minimum under-keel clearances, or engineering surveys, or where a full bottom search is required, should preferably be surveyed using multibeam or multi-transducer systems. Single beam echo sounders augmented with the use of side scan sonar may be used. Closer line spacing may be necessary in order to provide the best possible coverage for the higher orders. The work must be done according to the accuracies and specifications detailed for Exclusive Order, Special Order, Order 1a and 1b or Order 2.
In less critical areas, sounding lines using single beam echo sounders may sufficiently cover the area to be surveyed using the line spacing stated in Table 1 – Standards for Bathymetric Data of the CHS Standards for Hydrographic Surveys, and multibeam or multi-transducer systems employed without overlap between adjacent track lines could also be used. The work must be done according to the accuracies and specifications detailed for Order 1a and 1b, Order 2 or Order 3.
The survey order, the type of echo sounders used, and the line spacing will help determine the amount of work to be done and provide a time and resource budget for the project.
3.3 Pertinent documents
Charted bathymetric information may come from a variety of sources, some of which do not originate from the CHS. The bathymetric data obtained from a new survey must be compared to the existing source documents and publications. Obtain a list of the documents that were used for the preliminary analysis of the project.
The following is a list of documents and publications which should be brought into the field. Depending on the nature of the project, it may not be necessary to have on hand all the documents and publications listed below.
- copies of the latest corrected edition of the charts for the survey area
- a list of specific chart investigations requested by the Chart Production section
- a list of specific queries and updates requested by the Sailing Directions unit
- copies of previous field sheets and source plans, if any (preferably in digital form)
- up to date aerial photographs and topographic maps of the area
- a copy of related publications for the area of work: Sailing Directions, Tide Tables and Monthly Water Level Bulletins, List of Lights, Buoys and Fog Signals, non-government publications that provide information to boaters.
- listings of the positions of all horizontal control points and conspicuous objects in the area of work as well as their descriptions (from GSD, provincial governments, CHS, etc.)
- a listing of the elevations of all vertical control points in the area of work as well as their descriptions (from GSD, provincial governments, CHS, etc.)
- listing of the latest position of fixed and floating aids (from CCG database - SIPA).
- all necessary file numbers, etc., obtained from HDC/Data Management
- CHSDir, BDB and HPD extracts
Agencies such as Small Craft Harbours, Port Authorities, Transport Canada (Navigable Waters Protection Act), Public Works, local authorities, etc. should be contacted in order to obtain information on upcoming construction, dredging operations, etc. in the area to be surveyed.
Reference documents pertaining to the operation and calibration procedures of specific equipment as well as owner’s manuals of the various equipment used during the survey should be on hand.
There should also be on hand other reference documents such as working conventions, administrative rules and procedures, safety manuals and regulations that govern hydrographic surveying, etc.
3.4 Tidal instructions
It is customary to submit a hydrographic survey project to the Tides and Water Level Unit who in turn analyzes the request and produces specific instructions for the project. This should be done well in advance so that the requested information will be ready well ahead of the departure date.
These instructions should contain the following:
- sounding datum
- datum of elevations
- how soundings will be reduced (water level staff, water level gauge readings, co-tidal chart, predictions, etc.)
- time zone to utilize
- location of permanent water level gauges (tidal/non-tidal) in the area of work and a copy of their inspection history
- a statement specifying if datum is to be determined by water level transfer and from which reference station
- location where temporary water level gauge should be installed
- requirements for long term water level observations
- TPU information should be provided
- other specific requirements such as tidal stream or current observations
All work is to be done in accordance with the procedures and accuracies stated in the CHS Standards for Hydrographic Surveys and the Canadian Tidal Manual.
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