An Investigation into the use of a RTK GNSS and a Digital Depth Sounder for Mapping a Tidal River Bed

Traditionally, Surveying through water catchments has been conducted through the use of either traditional land surveying techniques or through the use of hydrographic surveying techniques. As we looking into the future, we are always looking to improve our methods and techniques in order to achieve a more viable outcome with regards to safety and accuracy. Topographic Surveys are often met with a water storage of some type, particularly in rural areas, and often the surveyor is met with the task of attempting to model the bed of the water storage. The surveyor would generally undertake traditional land surveying techniques in order to manipulate a surface model; however this method can be seen as both hazardous and dangerous to the surveyor and surrounding bystanders. The aim of this dissertation will be to assess whether an RTK GNSS receiver linked with a digital depth sounder is an adequate tool for conducting surveys where a body of water is apparent. The results will display accuracies when comparing the Digital Depth Sounder’s surface to a reference surface, and also comparing traditional survey techniques to the reference surface. The results will also look into the time and cost parameters associated with the two different types of surveys. The surveys will be undertaken in a river bed, allowing for a reference surface to be produced at low tide, and the two comparison surfaces to be undertaken at high tide to allow for a body of water to be apparent above the surface under investigation. Comparison surfaces will be established, where the two surfaces will be overlayed onto the reference surface, allowing for a complete surface analysis to be performed. The findings of this project show that the RTK GNSS receiver linked to a digital depth sounder is feasible for undertaking surface data within a body of water, however some limitations need to be taken into direct consideration, and reading this report will allow for surveyors to make their own judgement