Indices

Formula

Reference

Percentage Sodium, Na%

% Na = Na + + K + Na + + K + + Ca 2 + + Mg 2 + × 100

Wilcox (1955)

Kelly Ratio, KR

KR = Na + Ca 2 + + Mg 2 +

Kelley (1940)

Magnesium Absorption Ratio, MAR

MAR = ( Mg 2 + Mg 2 + + Ca 2 + ) 100

Szaboles & Barab (1964)

Total Hardness, HT

TH (CaCO3) mg/L = 2.5 Ca2+ + 4.1 Mg2+

Todd (1980)

Residual Sodium Carbonate, RSC

RSC = ( CO 3 + HCO 3 ( Ca + Mg ) )

Eaton (1950) and Raghunath (1987)

Sodium Absorption Ratio, SAR

SAR = Na Ca + Mg 2

Richards (1954)

Permeability Index, PI

PI = ( ( Na + K ) + HCO 3 ) 100 Ca + Mg + Na + K

Doneen (1962)

Water Quality Index, WQI

WQI = i = 1 n W i q i [ i = 1 n W i ] 1

Sisodia & Moundiotiya (2006)