Translations:Versickerung und Retention/69/en

$={\dfrac {A_{u}\cdot 10^{-7}\cdot r_{D(n)}}{{\tfrac {b_{R}\cdot h_{R}\cdot s_{RR}}{D\cdot 60\cdot f_{Z}}}+(b_{R}+{\frac {h_{R}}{2}})\cdot {\frac {k_{f}}{2}}}}$