Table 6-5. Comparisons of annual sand accumulation and dune growth rates 



Location 



Species 



Crest growth 

 (m) (ft) 



Sand Growth 



accumulation period 

 (ra^/m) (yd^/ft) (yr) 



Nauset Beach 

 Cape Cod , Mass . 



American 

 beachgrass 



0.3 



0.2 



0.9 



0.6 



8.3 



8.3^ 



3.3 



3.3^ 



Ocracoke Island, N.C. American 



beachgrass 



Padre Island, Tex. Sea oats and 0.5 to 0.6 1.5 to 2.0 8.3 to 13.0 3.3 to 5.2 

 beachgrass 



Clatsop Plains, Oreg. European 



beachgrass 



0.3 



0.9 



13.8 



5.5 



10 



30 



^After Knutson (1980). 

 ^Three years growth. 



The European beachgrass annual trapping rate on Clatsop Spit, Oregon, has 



averaged about 4 cubic meters (5 cubic yards). Although surveys were not 



taken until nearly 30 years after planting (Kidby and Oliver, 1965), the 

 initial trapping rates must have been greater (see Fig. 6-38). 



200 400 



(ft) 



J I L 



300 



(ml 



Distance from Base Line 



Figure 6-38. European beachgrass dune, Clatsop Spit, Oregon. 



6-52 



