In a field test of a geological formation of permeable soil (porosity = $20 \%$ ), the hydraulic gradient was found to be $2 \%$. The actual seepage velocity of the flow was found to be $0.0025 \mathrm{~m} / \mathrm{s}$. Assume that the flow is in the laminar regime. The permeability $(K)$ of the aquifer is ____________ $\mathrm{m} / \mathrm{s}$ $\text{(rounded off to three decimal places)}$.
