SAND VOLUME 

 lyds^/lifi II ol beochl 

 Time(Monlhs) Cumulolive Intervol 







36 



96 



29 6 III 8) 29 G (IIS) 

 72 2 128 81 42 6 II70I 



20 - 



e 3 - £ 



2 - 



2 - 



I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I i _ 

 ■Gulf of Mexico 60-90in-*^ Loguno IHodre 1,370 -1,520m m 



■' /■•-/ 



,36 Months 



Initiol Ground Level 



' I I I LJ L. 



I Gross Planted j 



n Month I 



' I I ' I I 



I ' I I I I I I I I I I I I I I I I I 



20 40 



60 



_L 



80 100 

 IftI 

 I l_ 



120 140 



160 



180 



200 



10 



20 



30 



(ml 



40 



50 



60 



Distonce from Bose Line 

 Figure 6-37. Sea oats dune, Padre Island, Texas. 



Foredune restoration is most likely to succeed when the new dune 

 coincides with the natural vegetation line or foredune line. The initial 

 planting should be a strip 15 meters wide, parallel to the shore, and 15 

 meters landward of this line. It is essential that part of the strip be 

 planted at a density that will stop sand movement sometime during the first 

 year. If a natural vegetation or foredune line is not evident, restoration 

 should begin at least 75 to 90 meters (250 to 300 feet) inland from the HWL. 

 Where beach recession is occurring, the dune location should be determined 

 from the average erosion rate and the desired dune life. Another 15-meter- 

 wide strip may be added immediately seaward 4 to 5 years later if a base of 30 

 meters has not been achieved by natural vegetative spread. 



^' Trappin g Capacity . Periodic cross-sectional surveys were made of 

 some plantings to determine the volume of trapped sand and to document the 

 profile of the developing dune. Table 6-5 presents comparisons of annual sand 

 accumulation and dune growth rates. The rates are averaged over a number of 

 profiles under different planting conditions, and should be considered only as 

 an indicator of the dune-building capability. 



6-51 



