TECHNIQUES AND MATERIALS 



Plant Species 



The major objectives of vegetative marsh management are to offset the conversion of marsh to 

 open water and to control the erosion at marsh-water interfaces. These efforts are directed 

 primarily at the intertidal or water-saturated zone. Therefore, those plant species that can thrive 

 under these conditions are the major candidates for wetland restoration efforts in Louisiana. 



Cutgrass has excellent potential in areas with fairly fresh water, and smooth cordgrass can be 

 used where conditions are too saline for cutgrass. These two species are exceptionally well adapted 

 to waterlogged conditions, and together will cover nearly the entire spectrum of salinity regimes 

 in Louisiana (Louisiana Marshlands Plant Materials Laboratory 1986). Other plants suited for 

 marsh work include Avicennia germinans, Panicwn hemitomon, Phragmites australis, and Spartina 

 patens (Mendelssohn and Hester 1985a; Louisiana Marshlands Plant Materials Laboratory 1986). 

 The author is conducting field evaluations of Scirpus calif omicus, Typha latifolia, and Eichhomia 

 crassipes in canal bank erosion control in an intermediate marsh. Some species that have been 

 tested for dune conditions are Panicum amarum, Uniola paniculata, Spartina patens, Sporobolus 

 virginicus (Mendelssohn and Hester 1985a), and Paspalum vaginatum (Mendelssohn and Hester 

 1985b). 



Seeding 



Seeding methods need to be refined to better exploit the cost-effectiveness of seeding as 

 compared to transplanting. The labor costs for seeding are drastically less than those for trans- 

 planting, and large areas can be seeded in the length of time required to transplant a relatively 

 small area. A commercial source of Louisiana wetland plant seeds and better seed handling and 

 distribution techniques are urgently needed. 



Hydroseeding could be used in succession acceleration when an increase in the influence of 

 marine water warrants the introduction of S. altemiflora because it fulfills two important 

 requirements of seeding this species: it keeps the seeds moist and it embeds the seeds in the 

 substrate. In addition, mulches, fertilizers, growth stimulants, fungicides, sticking agents, seeds of 

 other species, etc. can be added to the slurry and thus tailor the seeding to the site and manage- 

 ment objectives. 



The author conducted a preliminary hydroseeding experiment with S. altemiflora on a mud flat 

 in a brackish marsh near Mud Lake in Cameron Parish, LA. Louisiana Erosion Control, Inc., of 

 Port Allen, LA, provided a 1,300-gallon commercial hydroseeder for this purpose. The 

 experimental area exhibited a 15% survival rate after 5 weeks in spite of one of the worst 

 droughts in a decade. Preliminary arrangements for the testing of a scaled-down version of a 

 hydroseeder (more practical for use under marsh conditions) are underway. 



Wave-Dampening Fences 



The design of wave-dampening devices (see Figure 1) needs extensive investigation. The 

 structural requirements of the fences will vary according to the wave energy regime, the porosity 

 of the fence material, tidal amplitude, and the mechanical properties of the supporting sediment. 

 In addition, the wave energy behind the fence must be determined to predict the survival of 

 plantings so protected. 



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