Daily PEF diurnal variation 
Calculations using only preBD values for the day 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{PreBD\ amp\%high}^{\mathrm{6}}{=}\ \frac{\mathrm{highest\ preBD\ value}{}\mathrm{lowest\ preBD\ value}}{\mathrm{highest\ reading\ of\ the\ day}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{PreBD\ amp\%mean}^{\mathrm{8,10}}{=}\ \frac{\mathrm{highest\ preBD\ value}{}\mathrm{lowest\ preBD\ value}}{\mathrm{preBD\ mean\ of\ the\ day}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{PreBD\ morning/12\%\ mean}^{\mathrm{20}}{=}\ \frac{\mathrm{afternoon\ (12{\mbox{}}2\ \mbox{\textsc{pm}})\ preBD\ value}{}\mathrm{morning\ value}}{\mathrm{mean\ of\ the\ two\ values}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{PreBD\ morning/6\%\ mean}{=}\ \frac{\mathrm{evening\ (6{\mbox{}}9\ \mbox{\textsc{pm}})\ preBD\ value}{}\mathrm{morning\ value}}{\mathrm{mean\ of\ the\ two\ values}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Maximum/minimum\ (\%)}{=}\ \frac{\mathrm{highest\ value\ of\ the\ day\ }(\mathrm{afternoon\ or\ evening})}{\mathrm{lowest\ value\ of\ the\ day\ (morning\ or\ evening)}}{\times}100\) \end{document} 

Calculations using preBD and postBD values for the day 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Amp\%high}{=}\ \frac{\mathrm{highest\ value\ of\ the\ day}{}\mathrm{lowest\ value\ of\ the\ day}}{\mathrm{highest\ value\ of\ the\ day}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Amp\%mean}{=}\ \frac{\mathrm{highest\ value\ of\ the\ day}{}\mathrm{lowest\ value\ of\ the\ day}}{\mathrm{mean\ of\ the\ day}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Amp\%low}^{\mathrm{29}}{=}\ \frac{\mathrm{highest\ value\ of\ the\ day}{}\mathrm{lowest\ value\ of\ the\ day}}{\mathrm{lowest\ value\ of\ the\ day}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Timespecific\ amp\%mean\ (d)^{{\dagger}}}{=}\ \frac{\mathrm{postBD\ afternoon\ value}{}\mathrm{morning\ preBD\ value}}{\mathrm{mean\ of\ the\ day}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Timespecific\ amp\%mean\ (two)^{{\dagger}}}{=}\ \frac{\mathrm{postBD\ afternoon\ value}{}\mathrm{morning\ preBD\ value}}{\mathrm{mean\ of\ the\ two}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Timespecific\ amp\%mean\ (morning)^{{\dagger}}}{=}\ \frac{\mathrm{postBD\ afternoon\ value}{}\mathrm{morning\ preBD\ value}}{\mathrm{morning\ value}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Timespecific\ amp\%mean\ (evening)^{{\dagger}}}{=}\ \frac{\mathrm{postBD\ afternoon\ value}{}\mathrm{morning\ preBD\ value}}{\mathrm{evening\ value}}{\times}100\) \end{document} 

Indexes of mean daily and period variation (index number used in this study precede the index) 
Indexes using only preBD values for the period 
1 Mean preBD amp%high = average diurnal variation in preBD amp%high for the period 
2 Mean preBD amp%mean = average diurnal variation in preBD amp%mean for the period 
3 Mean preBD morning/12% mean = average diurnal variation in preBD morning/12% mean for the period 
4 Mean preBD morning/6% mean = average diurnal variation in preBD morning/12% mean for the period 
5 Mean maximum/minimum (%) = average diurnal variation in maximum/minimum (%) for the period 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{6\ PreBD\ amp\%high\ (period){=}}\ \frac{\mathrm{highest\ period\ preBD\ value}{}\mathrm{lowest\ period\ preBD\ value}}{\mathrm{highest\ preBD\ value\ of\ the\ period}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{7\ PreBD\ amp\%mean\ (period)}{=}\ \frac{\mathrm{highest\ period\ preBD\ value}{}\mathrm{lowest\ period\ preBD\ value}}{\mathrm{mean\ preBD\ value\ of\ the\ period}}{\times}100\) \end{document} 

Indexes of mean daily and period variation (index number used in this study precede the index) 

Calculations using preBD and postBD values for the day 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{8\ Amp\%low\ of\ means}^{\mathrm{29}}{=}\ \frac{\mathrm{highest\ daily\ mean}{}\mathrm{lowest\ daily\ mean}}{\mathrm{lowest\ daily\ mean}}{\times}100\) \end{document} 

9 Mean amp%high^{10}^{,14}^{,23}^{,37}^{,41–}^{42} = average diurnal variation in amp%high for the period 
10 Mean amp%mean^{12}^{,16–}^{17}^{,37}^{,41} = average diurnal variation in amp%mean for period 
11 Mean amp%low^{29} = average diurnal variation in amp%low for the period 
12 Highest amp%low^{29} = highest amp%low for the period 
13 Mean timespecific amp%mean (d)^{*} = average diurnal variation in timespecific amp%mean (d) for period 
14 Mean timespecific amp%mean (two)^{*} = average diurnal variation in timespecific amp%mean (two) for period 
15 Mean timespecific amp%mean (am)^{*} = average diurnal variation in timespecific amp%mean (morning) for period 
16 Mean timespecific amp%mean (pm)^{*} = average diurnal variation in timespecific amp%mean (evening) for period 
\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{17\ Period\ amp\%high}{=}\ \frac{\mathrm{highest\ value\ of\ the\ period}{}\mathrm{lowest\ value\ of\ the\ period}}{\mathrm{highest\ value\ of\ the\ period}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{18\ Period\ amp\%mean}{=}\ \frac{\mathrm{highest\ value\ of\ the\ period}{}\mathrm{lowest\ value\ of\ the\ period}}{\mathrm{mean\ of\ the\ period}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{19\ Period\ amp\%low}{=}\ \frac{\mathrm{highest\ value\ of\ the\ period}{}\mathrm{lowest\ value\ of\ the\ period}}{\mathrm{lowest\ value\ of\ the\ period}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{20\ Lowest\%mean}^{\mathrm{37}}{=}\ \frac{\mathrm{lowest\ value\ of\ the\ period}}{\mathrm{mean\ of\ the\ period}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{21\ Secondlowest\%mean}^{\mathrm{37}}{=}\ \frac{\mathrm{second\ lowest\ value\ of\ the\ period}}{\mathrm{mean\ of\ the\ period}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{22\ Lowest\%mean}^{\mathrm{37}}{=}\ \frac{\mathrm{third\ lowest\ value\ of\ the\ period}}{\mathrm{mean\ of\ the\ period}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{23\ Twolowest\%mean}^{\mathrm{21,37}}{=}\ \frac{\mathrm{mean\ of\ the\ two\ lowest\ values\ in\ the\ period}}{\mathrm{mean\ of\ the\ period}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{24\ Threelowest\%mean}^{\mathrm{37}}{=}\ \frac{\mathrm{mean\ of\ the\ three\ lowest\ values\ in\ the\ period}}{\mathrm{mean\ of\ the\ period}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{25\ Lowest\ morning\%best}^{\mathrm{46}}{=}\ \frac{\mathrm{lowest\ value\ of\ the\ period}}{\mathrm{best\ recorded\ by\ flow\ meter}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{26\ Extreme\ readings\ ratio}^{\mathrm{37}}{=}\ \frac{\mathrm{lowest\ value\ of\ the\ period}}{\mathrm{highest\ value\ of\ the\ period}}{\times}100\) \end{document} 

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{27\ Extreme\ pairs\ ratio}^{\mathrm{37}}{=}\ \frac{\mathrm{sum\ of\ lowest\ two\ values\ of\ the\ period}}{\mathrm{sum\ of\ highest\ two\ values\ of\ the\ period}}{\times}100\) \end{document} 

28 Twohighest average^{16}^{,37} = sum of two highest amp%mean/2 