Beverley Brook & Tributaries Survey

Study:

Watercourse survey of Beverley Brook and tributaries in South West London to improve the Environment Agencys flood maps for the area.

Approximately 113 cross sections were requested along with detailed bank top levels every 5 meters through Wimbledon Common.

Client Requirements:

  • Channel Cross Sections & Hydraulic Structures in AutoCAD format. Surveyed at requested locations, presented with Hard & Soft Bed.
  • Long Section profile in AutoCAD format, presented at an appropriate scale.
  • Location Plan displaying Cross Section locations along with bank levels surveyed through Wimbledon Common.
  • Data outputted in EACSD, ISIS & XYZ format.
  • Survey report and photographs of each Cross Section. Each photograph named with the Cross Section name and a description.
  • Seven new Control Stations were to be installed along the watercourse extent, surveyed to E6 grade specification.

Survey & Deliverables

  • As the downstream extent of this survey was situated at the confluence to the Thames – a detailed Risk Assessment & Method Statement was generated.
  • Tide times were checked so that surveyors were able to collect the data in the lowest water levels and as safely as possible.
  • Due to the watercourse running through a number of residential properties, a letter drop was deployed 7 days before the survey start date. This ensured our surveyors could work efficiently and access for these cross sections was pre-arranged.
  • Digital OS Mapping was obtained and the requested cross section locations and bank level polygons were overlayed onto this.
  • A site folder was made which included the OS Mapping, existing OSBMs and Control Stations description sheets for surveyors to cross check whilst on site.
  • All cross section locations were uploaded onto the GNSS Receiver.
  • Starting at the downstream extent, surveyors made their way upstream collecting data at each cross section location, taking geo-referenced photographs as they progressed.
  • Reflector & Reflector-less Total Station techniques were utilised to carry out this survey.
  • Survey data was downloaded and stored at the end of each day and checked to ensure no information had been overlooked.
  • Safe practices were carried out at all times and the prepared Risk Assessment and Method Statement were adhered to throughout.
  • A number of OSBMs were located on Hydraulic structures using our prepared OSBM location spreadsheets. These were checked against this survey using the tolerances set out in the EA Specification.
  • Checks were deployed on the existing control stations using a GNSS Receiver stabilised with a bipod.
  • Progress reports sent to client at the end of each week. Schedule for following week included.
  • Data outputs included ISIS, XYZ & EACSD.
  • A report was produced with a comparison table showing differences between existing control station coordinates/OSBM levels & new Precision Point Surveys coordinates/levels.
  • Cross Sections, Long Section and Location Plans were presented in AutoCAD format.
  • Gauge Board description sheets produced for all Gauge Boards surveyed on the watercourses.
  • In-house processing procedures followed to maintain consistency.
  • Independent checking system carried out.

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2018-11-04T20:26:11+00:00