

Table 2. San Luis Pass 



tidal ranges. 





Date 



Location and gage 



Diurnal 

 range, R 



Ratio 



of ranges 



Pier 



San Luis 







(ft) 







Oct. 1933 



Just Inside inlet (NOS) 



1.13 











Nov. 1936 



Just inside inlet 

 Karancahua Reef 



0.71 

 0.89 







June 1937 



Just inside inlet 

 Karancahua Reef 



0.72 

 0.90 







Sept. to Nov. 



Galveston Pleasure Pier (NOS) 



2.06 



I -00 





1965 



Jsnaica Beach, West Bay (NOS) 



0.98 



0.48 







Chocolate Bayou CSVfG) 



0.98 



0.48 





July to Aug. 



Galvestcn Pleasure Pier (NOS) 



2.16 



1.00 







1969 



San Luis bridge (SWG) 



1.81 



0.84 



1.00 





Christmas Day (NOS) 



0.98 



0.45 



0.54 





Alligator Point (NOS) 



0.91 



0.42 



0.50 





Chocolate Bayou (SWG) 



0.94 



0.44 



0.52 



1974 



Galveston Pleasure Pier (NOS) 



2.18 



1.00 









San Luis Pass bridge (SWG) 



1.62 



0.74 



1.00 





Chocolate Bayou (SWG) 



1.05 



0.48 



0.65 



July 197A 



Galveston Pleasure Pier (NOS) 



2.18 



1.00 









San Luis Pass bridge (SWG) 



1.72 



0.79 



1.00 





Chocolate Bayou (SWG) 



0.95 



0.44 



0.55 



20 to 23 July 



San Luis Pass bridge (SWG) 



1.54 







1.00 



1976 



Chocolate Bayou (SWG) 



0.98 







0.64 



Table 3. Tidal 



lags in San Luis Pass system 



Location 





High water lag 



Low water lag 







(hr) 



(hr) 



San Luis Pass 





0.0 



0.0 



Galveston Pier 





0.25 



0.0 



Alligator Point 





6.0 



4.25 



Christmas Bay 





6.1 



3.5 



Chocolate Bayou 





7.6 



6.25 



However, the high water lags in West and Christmas Bays are about 6 hours, and 

 low water lags are substantially less. ■ These phase lags are considerably 

 greater than those predicted from shallow-water theory.. For example, the 

 distance from the San Luis Pass gage to the Chocolate Bayou gage is about 

 60,000 feet. If an average depth of 5 feet is assumed, the traveltime for a 

 long wave would be about 1.3 hours. 



In a few cases, high water lags of as much as 15 hours occurred, due to 

 distortion of the dual-peak gulf water level fluctuation. The second peak, 

 which is lower on the open coast, is more readily transmitted through the 

 inlet due to the higher water level. Consequently, the water reaches a 

 greater amplitude in the bay than during the first peak. An example of this 

 situation is shown in Figure 33. 



d. Tidal Hydralulics . Current and discharge characteristics of San Luis 

 Pass are summarized; the total discharge through the pass was computed as 

 follows: When two or three current measurement stations were located in the 

 gorge, as in 1962 and June 1976, the gorge cross section was subdivided into 

 parts whose boundaries were equidistant (horizontally and vertically) from 

 current meter locations. Each of these parts was then multiplied by the 



41 



