Monday May 21, 2018

 

Hydrography

Dredging and Hydrography

Officer: Bijan Salimi

Phone Number: 013-44992259

Hydrography is a branch of practical science that discusses about measuring and describing the physical effects of the seas and other water sources and their adjacent coastal areas and the sea related phenomena like tides, determination of deposition rate and pattern, reorganization of water flows, environment protection and etc.    

 

The most important and applicable achievement of Hydrographic operations is the preparation of marine maps in order to provide safe movements of vessels in marine zones.

At present, Hydrography is changing and there are basic changes happening in its measuring technology. The single and multi beam echo sounder systems and air laser system present a complete covering of water source bed compared to the measurements in vector profile echo sounder methods. The capability of determining accurate data position on the earth has increased to a great level by means of satellite positioning systems. Nowadays, we are able to register a great volume of accurate hydrographic data in order to prepare accurate maps for engineering and navigation affairs by digital and instant combination of satellite positioning systems and digital electro-acoustic echo sounders.

The echo sunder devices are classified as follow:

  1. Single beam echo sounder applications that have achieved accuracy better than decimeter in shallow waters.

  2. Multi beam echo sounder technology that is developing very fast and presents numerous potential facilities for complete and accurate investigation of the bed.

  3. Air laser echo sounding is a new technology that is beneficial in the mapping of shallow and clear waters.

After the preparation of hydrographic maps in ports and analyzing them, some projects will begin in order to perform dredging operations (deepening or maintaining) to preserve channels' depth and to provide safe movements for the vessels.

Dredging is the removal of sediments and debris from the bottom of sea, waterways and water ponds which is done by means of various dredging equipment. It might also be done in order to create depth and establish channels or waterways or to increase the depth of ponds and water zones. The type of dredging equipment has direct relationship with the type and structure of the bed and also the basic water depth in that zone.

By having Yasin Hyper-Suction dredger with a capacity of 1000 m3 and Shahid Rashidi Cutter-suction dredger with a capacity of 300 m3 per hour and Mohajer grab dredger, Ports and Maritime Administration of Guilan Province efforts consecutively in order to provide the required depth for the berthing of huge vessels.

The water swings are also registered by means of the oldest tide gage application existed in Caspian Sea installed in Anzali Port in 1926. The obtained statistics that are collected daily at 8:00, 12:00 and 18:00 O'clock will be sent to study centers and related organizations at the end of each month.