[R = recharge (mm/a); P = mean annual precipitation (mm/a); Clp = chloride in rain (mg/l); D = dry chloride deposition (mg/m2/a); Clw = Clsw = chloride concentration (mg/l) in soil water below active root zone in unsaturated zone OR Clw = Clgw = chloride concentration (mg/l) of groundwater where for many boreholes the Clgw = harmonic mean of the Cl content in the boreholes]