dunes range from 10 to 30 feet in height, and form a substantial bulwark 

 against hurricane surges, except for those low passes where the dunes are 

 disconnected. All of the four test sites are barren portions of the 

 islands where the land slopes gently from the Gulf shoreline to low crests 

 and then down to the bays. The experiments were all made on land ranging 

 from 2 1/2 to 4 1/2 feet above mean sea level. The diurnal range of tide 

 is 1.2 feet at San Luis Pass and 1.7 feet at Aransas Pass near the Padre 

 Island sites. The maximum tidal range is about 2.2 feet at San Luis Pass 

 and about 2.5 feet at Aransas Pass. The four study areas, designated San 

 Luis Pass, Packery Channel, Newport Pass, and Corpus Christi pass, are 

 shown on Figures 1 and 2 . 



Wind diagrams for the Galveston and Corpus Christi areas are shown 

 in Figure 3. Analyses of nine random samples taken at various times from 

 the four study areas showed little or no differences in sand size. Ninety 

 percent of the sampled sand ranged from 0.08 to 0.2 mm in diameter. Small 

 sea shells and shell fragments are mixed with the sand. The fine to very 

 fine sand found on the Texas coast is readily transported by normal winds. 

 During periods of light rain and average wind velocities, sand movement 

 has been observed in the study areas. The diagrams show that the prevail- 

 ing winds are from directions roughly perpendicular to the coastline, which 

 results in movement of the beach sand inland toward the bays. 



3. STUDY DESCRIPTION 



Creating dunes by the use of junk car bodies instead of conventional 

 wood slat fencing was attempted during the earlier stages of the experi- 

 ments. It was reasoned that if the car bodies would trap sand, they might 

 also act as reinforcement to stabilize the newly formed dunes. The car 

 bodies were placed in line parallel to the beaches and for a few weeks 

 appeared to be trapping sand in amounts about equal to that trapped by 

 wood slat fencing. However, after an initial accumulation, the rate of 

 entrapment by the car bodies appeared to diminish rapidly, and the total 

 results were obviously less effective than those produced by the wooden 

 fencing. The ground elevations where car bodies were placed originally 

 were generally lower than those where sand fences were placed. Abnormally 

 high tides caused greater damage to sand accumulations in those lower 

 areas. During normal tide periods, natural deposition of beach materials 

 seemed to be generally greater in the lower areas occupied by the car 

 bodies. Because of this natural accreting action, it is probable that 

 sand accumulated in areas up to 50 feet on either side of the car bodies 

 may not be entirely attributable to those barriers. (See Figures 5, 13, 

 and 14.) Car bodies in place are more costly than conventional wood- 

 picket or fabric fencing and apparently trap less sand. Consequently, 

 experiments to build dunes with car bodies have been discontinued by the 

 Galveston District. 



Wood picket "snow" fencing was used in most of the sand dune experi- 

 ments. The fencing consisted of rough cut, square top, yellow pine pickets 

 3/8 inch thick, 2 inches wide, 4 feet long and woven with five 2-strand 



