b. Time - integrating . 



(1) Sample bags 



Many types of vertically mounted sample bag traps have been 

 developed for use in the surf zone (Inman 1949; Hom-ma, 

 Horikawa, and Sonu 1960; Nagata 1961, 1964; James and 

 Brenninkmeyer 1971; Katori 1982; Kraus 1987). The streamer 

 trap investigated in the present study is a type of 

 vertically mounted sample bag apparatus; however, because 

 both bed and suspended load are collected to yield the 

 vertical distribution of the total load, this device is 

 discussed in the "Total Load" section. One type of 

 suspended sample bag trap, developed by James and 

 Brenninkmeyer (1971), consists of a 1-cm-diameter nozzle 

 connected to a 3.25-cm tube collection area with stainless 

 steel mesh screen at the rear (Figure A14). Sediment 

 entering the nozzle is deposited in the tube while water 

 passes through the mesh. Five of the tubes are vertically 

 arranged at 7-cm intervals, mounted on a galvanized steel 

 pipe. The steel pipe has 1-cm-diameter holes drilled at 

 the same elevations as the tubes such that the trap can 

 begin sampling when the steel pipe is rotated. Various 

 geometric designs of the sampler were tested in a circulat- 

 ing flume; the chosen design was shown to create little 

 turbulence. This device was used to measure the distribu- 

 tion of suspended sediment in bores and backwash at Nauset 

 Light Beach on Cape Cod, Massachusetts. Disadvantages of 

 this type of apparatus include: (a) the sampler nozzle may 

 disturb the flow; (b) the apparatus may induce scour at the 

 bed, thereby increasing the quantity of sediment in 

 suspension; and (c) sediment with nominal grain size 

 smaller than the mesh diameter passes through the sampler. 



(2) Bamboo samplers 



Inexpensive bamboo samplers consisting of a bamboo pole 

 with small holes at intervals and concrete blocks at the 

 base to weight the apparatus have been used in the surf 

 zone to measure the vertical distribution of suspended 

 sediment (Fukushima and Mizoguchi 1958, Fukushima and 

 Kashiwamura 1959, Hom-ma and Horikawa 1962, Noda 1962, 

 Basinski and Lewandowski 1974). Bamboo samplers, because 

 they are light and buoyant, tend to move with both the wind 

 and waves. Sediment is deposited in the hollows between 

 joints. Fukushima and Mizoguchi (1958) deployed 5-m-high 

 bamboo samplers along the coast of Hokkaido in Japan. The 

 samplers were removed from the surf zone after a week or 

 so, and the bamboo poles cut into lengths of about 1 m for 



A23 



