Hydrographic surveying is also called bathymetric surveying. This is an inspection of bodily details present underwater. It is a branch of science in which all the factors and physical bodies present underwater are been examined in detail. These factors are worth studying as they affect all marine activities, for example, marine structure, dredging, or offshore drilling. Hydrographic surveying always conducts due to the interest of the authority which is conducting this survey. Means of the sensor, sound, and electronic sensor system are the means through which this survey is been conducted in shallow water.
All the information collected through this hydrographic surveying is collected and bring back with the help of nautical charts which contain;
- Improve channels
- Available depths
- The aids to navigation harbor facility
While constructing or developing port facilities this process of hydrographic surveying method is being very much helpful in this case. In developing port facilities, hydrographic surveying plays an important part for collecting necessary information regarding underground structures. This will help out in having idea about the loss of capacity due to any reason.
Initial steps in hydrographic surveying
First of all, in this procedure, the control lines are drawn on the shore, so that the constructor could get idea about further proceedings. For determining the depth at different points at the shore, sounding method is applied with the help of stationary boats. Sounding location can be created in two ways; either from boat to the control points or by fixing the point in the boat and then taking the boat away from the control point. Before applying this procedure, following steps have to be followed:
- Locations horizontal control
- Locating vertical control
As early preparations, reconnaissance is a crucial step in starting a project so that a project I’m an be completed effectively and economically easily. A complete reconnaissance of an area is sufficient for choosing the best area to perform hydrographic surveying. This will be much beneficial in the completion of the project being under the governing powers or authority. Aerial photographs are being used in this kind of studies or surveys.
Locating the horizontal control point is so important in all the process so that the workers could know about the features of the marine. So, a number of lines or azimuth us are constructed by using any method. For rough work or constructing a rough idea, radiometric and plane table surveys are being used in this whole process. There are no such rules for constructing horizontal control point locating process, however, some points are kept in consideration while doing this;
- If water body is 1 km wide than it is significant to do this transverse along each coast.
- If water body is narrower or less wide than 1 km then the transverse lines will run a long only one coast.
- If there is vegetation along the shore line then triangulation system must be applied for this survey.
- Triangulation system will be varying with the size of the shore or ocean lines; the bigger the ocean or shore size, the wider the triangulation system and vice verse.
- Before sounding it is essential to locate the vertical control lines. Benchmarks are used to determine the vertical control on the shore. Basically, branch marks are used for setting or checking lit the levels of guages.
Civil surveyors perform the task of measurement the Earth at a large scale. This whole process involves, measuring data determination, reduction of the data, interpretation of the data to the usable form. After that, the relative positions are determined so that required measurements could be done.
There are two opposite functions in the surveying however the are similar to each other:
- Using the process of mapping, the civil surveyor will determine the existing horizontal and vertical control lines on the shore.
- Civil surveyors may construct the new control lines so that the borderline and structure of the marine could be estimated.
For so many years, civil surveyors are being performed a crucial role in the whole process of sounding and surveying. The process of surveying is one of the basic and most important steps in any type of construction whether it’s commercial or public.
Except for the tools being used, the technique of hydrographic surveying and the role of the civil surveyor is the same all over the world. The instruments used in this process are mostly made in the US, Australia, Japan.Share