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|Title:||Monitoring of foredunes on Padre Island, Texas|
|Authors:||Texas Tech University. Department of Range and Wildlife Management|
Dahl, Bill E.
Goen, John P.
Padre Island, Texas
|Publisher:||Coastal Engineering Research Center (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Miscellaneous report (Coastal Engineering Research Center (U.S.)) ; no. 77-8.|
Abstract: This study was conducted to continue monitoring foredunes formed from grass plantings made during 1969 to 1973 on north Padre Island beaches. This report summarizes data obtained from elevational profiles and vegetative transects at four experimental foredune sections and one natural foredune section during 1975 and 1976. The beach and foredunes, a 655-foot (200 meters) cross section, gained S.7 cubic yards (4.4 cubic meters) per linear foot of beach from August 1975 to August 1976. However, sand accumulation was not uniform; the north end of the study area gained no sand. Plantings, 50 feet (15 meters) wide seaward of existing foredunes proved to be an effective dune-widening technique. This has provided a 125-foot (38 meters) dune base versus an 80-foot (24 meters) dune base from initial 100-foot-wide (30 meters) plantings. Sand-trapping rates averaged 6.3 cubic yards (4.8 cubic meters) per linear foot per year on foredunes of experimental plantings versus 4.0 cubic yards (3.1 cubic meters) for the unplanted, natural area. However, accumulation rates for the last year were 4.1 cubic yards for planted foredunes versus 4.0 cubic yards for the natural foredune. Apparently, the natural area is sufficiently vegetated to accumulate sand as rapidly as planted areas, but it has taken 15 years to reach this trapping efficiency and without a recognizable dune line. Rate of lateral grass spread from initial plantings varied from 5.25 to 7.24 feet (1.6 to 2.2 meters) per year. Vegetation studies show little invasion of unplanted species into the planted foredunes. Landward of planted dunes, grass establishment is well ahead of the unplanted area. The unplanted area is more arid. Mean elevations for dune crests 89 months after planting were 19.2 feet (5.9 meters) mean sea level versus 8.6 feet (2.6 meters) for the unplanted area.
|Rights:||Approved for Public Release, Distribution is Unlimited|
|Appears in Collections:||Miscellaneous Report|
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|MR-CERC-77-8.pdf||21.2 MB||Adobe PDF|