a. Alameda Creek (Area 2) Plantings . Area 2 is a particularly 

 high-energy site which is subject to both strong tidal currents and wind 

 waves. The site borders on a manmade breach in the South Bay levee 

 system. The breach connects the bay with a 100-acre pond. During high 

 and low tides, the pond is filled and emptied through the breached sec- 

 tion. During peak periods, velocities through the breach reach 0.5 to 

 1.0 meter per second (U.S. Army Engineer District, San Francisco, 1976). 

 In addition, this site is exposed to strong westerly winds which generate 

 waves over a broad fetch, 9 to 22 kilometers. Winds blow onshore at 

 Alameda Creek about 30 percent of the time at an average speed of 19 

 kilometers per hour. Observations using reference stakes indicate that 

 the 1.7-meter bank at this site erodes, several meters per year. 



The wave breakers had no effect on plant survival at Alameda Creek 

 (Table 4) . The unstable substrate eroded rapidly and the wave breakers 

 were frequently washed into the higher elevated pickleweed and saltgrass 

 zone. In addition, most plants at the Point Pinole and San Mateo sites 

 were planted on relatively level ground, beneath or on a mudbank; plants 

 at the Alameda Creek site were planted on an unstable, steep slope of the 

 mudbank where the plants were easily dislodged by waves. 



b. San Mateo Plantings . The San Mateo site is exposed to a fetch 

 similar to Alameda Creek, 14 to 21 kilometers. However, this site faces 

 northeast and is totally sheltered from the prevailing westerly winds. 

 Winds blow onshore only 14 percent of the time at an average speed of 

 8.3 kilometers per hour. 



At the San Mateo site, the beneficial effect of the wave breakers 

 was statistically significant by January 1977. During a 3-month period 

 (November 1976 to January 1977) , plant survival in all plots was about 

 50 percent. During the following 3 months (to April 1977) the apparent 

 difference in survival shown in Table 4 was, however, not statistically 

 significant due to high variability in one plot of each group in which 

 the plants died (student's t-test) . 



c. Point Pinole Plantings . The Point Pinole site is the most shel- 

 tered of the three sites. It faces northeast as does the San Mateo site, 

 but winds generate waves over a fetch of only 4 to 14 kilometers at this 

 site. At the Point Pinole site, the survival was significantly greater 

 in the wave breaker plots after the first month (October 1976; Table 4). 

 The t-test showed the probability of the null hypothesis (PH_) to be 

 smaller than 0.01. By January 1977, the effect of the wave breakers on 

 plant survival at Point Pinole was not statistically significant 



(0.30 < PH^ < 0,50). Wave activity had reduced plant survival in all 

 plots and the variability of the survival was too great for the t-test 

 to show a significant difference. 



Though individual wave breakers improved plug survival, it is evident 

 from these plantings that more formidable wave protection is required to 

 establish plants in these test areas. Earlier estimates (Knutson, 1977) 

 that California cordgrass can be established in areas with fetches up to 



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