Hydrographic Surveying

Hydrographic surveying is a vital service in supporting mapping of intertidal areas or region of creeks, rivers, lakes, salt water bodies and estuaries.

Our surveyors Mathew Berquist and Shane Gregory were requested by our client to undertake a further Hydrographic survey, to measure the depth water located at Kawana Lakes.  The requirement of the survey was to determine whether the canal bottom had returned to its original state, post construction of an overhead bridge and surrounding works in the immediate area.  Recently, Mathew returned to Kawana Lakes to repeat the same Hydrographic survey of the 200m section of water in the area, to evaluate if the remedial works undertaken were sufficient, or further excavation was needed.

Before commencing the Hydrographic survey, essential equipment and datum checks were carried out. This included checking GNSS height datums, tidal information and completing a “Bar check” to confirm that both the Echo Sounder and Transducer are returning correct measurements. Once these procedures were complete, Mat and a client representative travelled via a motorised vessel around the designated and surrounding areas, gathering continuous measurements of water depth.

Survey data is gathered from the Echo Sounder sending and receiving signals off the bottom of the canal, which in turn determine the depth. These soundings, combined with our GNSS receiver, which is continuously measuring our position, allow us to model the canal floor below.

“Hydrographic surveying is very similar to any conventional survey on land, in that we are making a number of observations to create a model of the physical surface, just in this case, the surface is underwater” said Mat.

Post survey, Mat then reduced all survey data gathered within a hydrographic survey specific software, drafted plans showing the survey information and delivered these to the client. The plans were then used to determine whether there was sufficient depth of water in the area, or in fact more materials were required to be excavated from the area.

Vessel

 

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