Water at $10C6=999\mathrm{.}7k\frac{g}{m^3}$ and $=1\mathrm{.}307{10}^{-3}k\frac{g}{m}*s)$ flows from a large reservoir to a smaller one through a $5-cm-$diameter cast iron piping system, as shown in the following figure. Determine the elevation $z_1$ for a flow rate of $6\frac{L}{s}.$ The friction factor of cast iron is $f=0\mathrm{.}0315.$