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<br />. <br /> <br />. <br /> <br />. <br /> <br />~'.... <br />W <br />0..1 <br />a <br /> <br />NOTES (Continued) <br /> <br />A number of changes have been made in the format of the data tables. <br />The monthly tables report TDS in mg/L instead of tons per acre-foot (the <br />annual summaries still report TDS in both mg/L and tons per acre-foot). <br />The monthly summaries include a column listing "Days wlo EC" which is <br />the number of days without conductivity data in that month. This was <br />included to indicate the quality of the estimated salt load value. When <br />daily conductivity is available, salt load is computed as a function of <br />conductivity and discharge. When conductivity is missing for an unregu- <br />lated station, salt load is computed as a function of discharge alone. <br />For stations with major discharge regulation, missing daily conductivi- <br />ties were interpolated from existing data. <br /> <br />Several regression statistics are listed in the annual summaries <br />and are defined as follows.' <br /> <br />1. The total number of samples in the regression analysis. <br /> <br />2. The percentage of samples with TDS as residue on evapora- <br />tion rather than Bum of constituents. <br /> <br />3. The percentage standard error of daily salt loads esti- <br />mated as a function of discharge and conductivity. <br /> <br />4. <br /> <br />The percentage standard error of dai ly salt loads esti- <br />mated as a function of discharge alone. <br /> <br />These statistics provide additional indication as to the quality of <br />annual and monthly salt load values. Those computed by a regression <br />equation which includes a large proportion of evaporation residue TDS <br />values may be biased because residue TDS is normally larger than the sum <br />of constituents. The errors in monthly and annual loads are assumed to <br />be less than the reported daily value standard errors because daily <br />errors may be offset by summation. <br /> <br />For several stations, the data record was not complete and monthly <br />values could not be computed using the new procedure. Standardized <br />methods for synthesizing loads and discharge for periods of missing data <br />are currently being investigated. Gaps in the following tables were <br />filled in with values from the previous progress report. These are <br />identified by an asterisk in the "Days wlo EC" column on the monthly <br />summaries or in the "Regression statistics" column on the annual sum- <br />maries. <br /> <br />140 <br /> <br />I <br />