Index

Formula

Reference

Percentage Sodium

$\%\text{Na}=\frac{{\text{Na}}^{\text{+}}+{\text{K}}^{\text{+}}}{{\text{Na}}^{\text{+}}+{\text{K}}^{\text{+}}+{\text{Ca}}^{\text{2+}}+{\text{Mg}}^{\text{2+}}}\times 100$

[14]

Kelly Ratio

$KR=\frac{{\text{Na}}^{\text{+}}}{{\text{Ca}}^{\text{2+}}+{\text{Mg}}^{\text{2+}}}$

[15]

Magnesium Absorption Ratio

$MAR=\left(\frac{{\text{Mg}}^{2+}}{{\text{Mg}}^{2+}+{\text{Ca}}^{2+}}\right)\times 100$

[16]

Total Hardness

TH(CaCO₃) mg/L = 2.5Ca²⁺ + 4.1Mg²⁺

[17]

Residual Sodium Carbonate

$RSC=\left({\text{CO}}_{\text{3}}+{\text{HCO}}_{\text{3}}-\left(\text{Ca}+\text{Mg}\right)\right)$

[18]

Sodium Absorption Ratio

$SAR=\frac{\text{Na}}{\sqrt{\frac{\text{Ca}+\text{Mg}}{2}}}$

[19]

Permeability Index

$PI=\frac{\left(\left(\text{Na}+\text{K}\right)+\sqrt{{\text{HCO}}_{\text{3}}}\right)\ast 100}{\text{Ca}+\text{Mg}+\text{Na}+\text{K}}$

[20]

Water Quality Index

$WQI={\displaystyle \sum _{i=1}^n{W}_i{q}_i}{\left[{{\displaystyle \sum _{i=1}^{n}W}}_i\right]}^{-1}$

[21]