(3) Sediments . Sediments on eroding bay shores typically con- 

 tain 5 percent sand, 15 percent coarse shell fragments and organic 

 debris, 15 percent silt, and 65 percent clay (Pestrong, 1972). Wave 

 action removes the fine-grained material from surface sediments in the 

 swash zone, leaving a surface layer of coarse material at the toe of 

 eroding banks. 



(4) Rainfall, Riverflow, and Salinity . Almost 85 percent of the 

 total annual rainfall in the San Francisco Bay occurs between November 

 and April. Major freshwater inflow, which coincides with the high rain- 

 fall periods, is in the northern reaches of the bay. During the winter 

 rains, salinity levels are greatly reduced in San Pablo Bay. Maximum 

 salinity levels reach the seawatet concentration (33 parts per thousand) 

 during the dry summer months in Central Bay and South San Francisco Bay, 

 Table 1 summarizes mean and extreme salinity levels in the three major 

 bays. 



Table 1. Salinity level 



s in San 



Francisco Bay. 



Location 



Salinity level (pet) | 



Maximum 



Minimum 



Mean 



South San Francisco Bay 



30.0 



18.0 



23.7 



Central Bay 



30.5 



18.0 



24.5 



San Pablo Bay 



23.5 



1.5 



11.5 



b. Location of Shoreline Planting Sites . Three shoreline sites were 

 selected for planting--San Mateo, Point Pinole, and Alameda Creek (Fig. 1) 

 The Point Pinole site is located on the east side of Point Pinole on the 

 southeastern shore of San Pablo Bay. The San Mateo site is on the west 

 side of South San Francisco Bay about 3 kilometers north of the San Mateo 

 Bridge. This site extends a distance of about 1 kilometer. Six planting 

 areas were established along the shoreline near the Alameda Creek flood 

 channel, hereafter referred to as Alameda Creek. This site is located 5 

 kilometers south of the San Mateo Bridge on the eastern shore of South 

 San Francisco Bay. The 1-kilometer test site, located north of the 

 Alameda Creek flood control channel, provided a wide variety of test 

 conditions. Physical characteristics of each of the planting sites are 

 summarized in Table 2. 



4. Planting Procedures . 



a. Seeding . 



(1) Laboratory Tests . Seeds were collected in November 1975 to 

 prepare for field planting. The seeds were harvested by hand at low tide. 

 Inflorescences (seed heads) were clipped from parent plants with the use 

 of electric garden shears. Collected material was threshed and stored in 

 40 parts per thousand saltwater at room temperature (about 20 Celsius) . 



14 



