near the site is valuable. If the area is a beach nourishment site, or 

 if the local Corps of Engineers District has a project near the site, 

 CERC's Littoral Environmental Observations (LEO) program may have been 

 established. LEO observers are excellent contacts to help determine 

 suitable sampling times. However, the field crew will have to make the 

 final determination of acceptable working conditions. 



3. Field Crew and Equipment . 



Teams of four are most effective. Ideally, persons able to partici- 

 pate throughout the study should be selected. This will save training 

 new people for each sampling trip and field crew performance will improve 

 with experience. Crew members should have flexible schedules to take 

 advantage of favorable weather. All members must be excellent swimmers 

 and at least two must be qualified scuba divers. Equipment needed to 

 quantitatively sample a high-energy beach is listed in Table 2. 



IV. DESIGN OF SAMPLING PLAN 



1. General Guidelines . 



Snedecor and Cochran (1967) identified two major problems confronting 

 an investigator: defining and conducting the sampling, and making correct 

 inferences about the population sampled. The objectives of a valid 

 sampling plan require a reduction of the variance of the parameters of 

 interest due to sampling error. This requires repeated sampling until 

 the samples estimate the actual population parameter within the desired 

 confidence limits. Sampling may be restricted to a few permanent sta- 

 tions within a defined area or may consist of transects and stations. 

 Usually a preliminary set of samples will have to be taken from a par- 

 ticular beach to determine the final sampling plan. Development of a 

 preliminary sampling plan depends on information generated from other 

 studies and the experience of the investigator. (Gonor and Kemp, 1978, 

 provide a compilation of procedures for quantitatively sampling inter- 

 tidal environments.) 



Three major questions must be answered to develop a quantitative 

 sampling plan: 



(a) Does the sampling device catch all or most of the 

 organisms found in a given volume of sediment? 



(b) How many replicates must be taken to be confident, 

 within certain statistical limits, that the parameter used 

 to describe a population are adequately estimated? 



(c) How should the replicates be distributed over the 

 study area? 



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