typical survey day, the boat may have to visit several different tide staffs 

 located along the channel, depending on the rate of coverage of an area,, or 

 station a survey crew member at the nearest staff to regularly report water 

 elevation via radio. A high density of staffs in some water bodies 

 probably reflects as much the need to reduce transit time to and from staff 

 visits as recognition that the water-level elevation changes along a water 

 body. 



Boat visits to the staffs can consume substantial time in going off 

 station, remaining at the staff for several minutes, and then returning on 

 station. An operational problem sometimes encountered is difficulty in 

 visually reading the tide staff in moderate waves and wind, which can 

 cause trouble in keeping the boat stationary at the staff. 



The tide staffs, which are typically mounted on timber survey 

 platforms, channel markers, bulkheads, etc., are routinely replaced as the 

 mounting structures are destroyed by barges or other vessels. Re- 

 installation of the staffs at the correct elevation often requires performance 

 of a level survey (if the tide station is near land or a survey table) or 

 knowledge of the water level based on a reading made at a nearby staff. 

 Figure 10 shows a staff being replaced by a Southern Area Office 

 surveyor. 



In discussions with CESWG hydrographic survey party personnel, 

 several operational needs were identified. Survey boats could remain on 

 station and continue surveying if the operators could simply phone to a 

 gauge and obtain the water level. The information reported by the gauge 

 must be in standard units (feet, local time), and a repeat option should be 

 available because of occasional noise or loss of attention due to other 

 duties on the survey boat. The water level should be reported in terms of 

 the CESWG navigation datum (presently mtl), or a table for converting 

 from the reporting datum to the navigation datum should be provided (e.g., 

 mllw to mlt). 



Chapter 3 Present Networks Along the Texas Coast 



23 



