By means of the Flathead conversion factor [~1.0 x 10° fissions/(dip counts/ min at 100 hours) ], the dip-counter results for the AOC’s from the skiffs have been converted to fissions per square foot in Table 4.1, so that they may be compared with the values for the other shots (Table 3.15), The dip-counter activities of all water samples, including those for the DE 365, are summarized in Table B.32. 4.2 DATA RELIABILITY The range and diversity of the measurements required for a project of this size virtually precludes the possibility of making general statements of accuracy which are applicable in all cases. Nevertheless, an attempt has been made in Table 4.2 to provide a qualitative evaluation of the accuracy of the various types of project measurements. Quantitative statements of accu- racy, and sometimes precision, are given and referenced where available. No attempt has been made, however, to summarize the errors listed in the tables of results in the text; and certain small errors, such as those in station locations in the lagoon area and instrument exposure and recovery times, have been neglected. Although the remaining estimates are based primarily on experience and judgment, comments have been included in most cases containing the principal factors contributing to the uncertainty, The following classification system is employed, giving both a quality rating and, where applicable, a probable accuracy range: Class A 4.3. Quality Accuracy Range Excellent + 0 to 10 percent B Cc D Good Fair Poor + 10 to 25 percent + 25 to 50 percent + = 50 percent N No information available CORRELATIONS 4.3.1 Fallout Predictions. As a part of operations in the Program 2 Control Center (Section 2.4), successive predictions were made of the location of the boundaries and hot line of the fallout pattern for each shot. (The hot line is defined in Reference 67 as that linear path through the fallout area along which the highest levels of activity occur relative to the levels in adjacent areas. The measured hot line in the figures was estimated from the observed contours, and the boundary established at the lowest isodose-rate line which was well delineated.) Thefinal predictions are shown superimposed on the interim fallout patterns from Reference 13 in Fig- ures 4.6 through 4.9. Allowance has been made for time variation of the winds during Shots Flathead and Navajo, and for time and space variation during Shots Zuni and Tewa. Predicted and observed times of fallout arrival at most of the major stations, as well as the maximum particle sizes predicted and observed at times of arrival, peak, and cessation, are also compared in Table 4.3. The marked differences in particle collections from close and distant stations are illustrated in Figure 4.10. In the majority of cases, agreement is close enoughto justify the assumptions used in making the predictions; in the remaining cases, the differences are suggestive of the way in which these assumptions should be altered. The faliout-forecasting method is described in detail in Reference 67. This method begins with a vertical-line source above the shot point, and assumes thatall particle sizes exist at 2+ altitudes; the arrival points of particles of several different sizes (75, 100, 200, and 350 mic: in diameter in this case), originating at the centers of successive 5,000-foot altitude incre=<: are then plotted on the surface. The measured winds are used to arrive at single vectors f:ur resentative of the winds in each layer, and these vectors are applied to the particle for th er: iod of time required for it to fall through the layer. 114 arm The required times are calculated ‘r cm