The first USC&GS chart of Sabine Pass, made in 1840 (Fig. 70, a), indicates 

 that the controlling depth was less than 6 feet, with a small, symmetrical ebb 

 tidal delta. Under the original improvement plan, an entrance channel 12 feet 

 deep, 150 feet wide, and 2.5 miles long, was to be maintained through the 

 bar. However, yearly dredging between 1876 and 1881 failed to maintain the 

 desired channel dimensions. Construction of two jetties began in 1883, and by 

 1885 they had extended 13,000 feet gulf ward (Fig. 70, b). Between 1840 and 

 1885 (Fig. 71, a) extensive deposition occurred in the nearshore zone on the 

 west (downdrift) side, and in an updrift fillet adjacent to the toe of the 

 east jetty. Over the years, the jetties were extended, raised, and repaired, 

 reaching their present lengths in 1929, with an 1,800-foot width at their 

 gulfward ends. Jetty construction has not produced the scouring action neces- 

 sary for enhanced self -maintenance , and dredging has been required almost 

 yearly since 1893. 



Following jetty construction, large fillets (1.7 million and 5.8 million 

 cubic yards) formed on both the west and east sides of the entrance, respec- 

 tively, with extensive offshore deposition (5.1 million cubic yards) west of 

 the jetty ends (Fig. 71,b). Erosion occurred seaward of the fillet on the 

 east side and between the fillet and deposition zone on the west. Blackman 

 (1938) attributed the west-side deposition to two principal causes. First, 

 longshore currents carrying very fine suspended material can more readily 

 retain it in suspension and carry it around and past the jetty ends for 

 deposit in the quieter waters west of the jetties. Second, much dredge spoil 

 has been deposited adjacent to the west jetty. More recent nearshore changes 

 (1966 to 1974) have been minor (Fig. 72) — a small area of deposition updrift 

 of the jetties and about 12,000 feet offshore. 



b. Tide Characteristics. 



(1) Summary of Hydraulic Data Collection . The first SWG tide meas- 

 urements at Port Arthur began on 29 December 1934 and continue to date. NOS 

 installed a control station tide gage in the pass in June 1958; the gage has 

 also operated continuously. SWG installed a continuously operating, permanent 

 gage on the southwest jetty in May 1965. Locations of these and other tide 

 and current measurement points are shown in Figure 73. 



Between June 1960 and April 1961, NOS operated a gage near the end of the 

 southwest jetty. This station was reestablished with a portable NOS gage 

 between 22 July and 26 August 1962, in connection with extensive current 

 measurements taken by NOS between 17 and 23 July. A temporary NOS gage was 

 also operating at Mesquite Point between 18 July and 9 August. In July 1966, 

 SWG installed a gage at the north end of Sabine Lake; the gage has operated 

 continuously since then. 



Tide data for the representative year (1974) at other locations were 

 incomplete for the Port Arthur gage, so 1973 data were used to examine varia- 

 bility in the tidal ranges and levels at four stations in the Sabine Pass-Lake 

 system. Unfortunately, the NOS pass gage was operational only between March 

 and August 1973. 



Finally, results of recent hydraulic studies were obtained from Ward and 

 Johnston (1977) and Ward and Chambers (1978). 



78 



