Water at $\backslash (50^\{\backslash$circ$\}\backslash$mathrm$\{$F$\}\backslash )$ flows by gravity from a large reservoir at a high elevation to a smaller elevation through a $120-$ft$-$long, $1\mathrm{.}5-$in$-$diameter cast iron piping system that includes four standard flanged elbows, a well$-$rounded entrance, a sharpedged exit, and a fully open gate valve. For a flow rate of $\backslash (8\backslash$mathrm$\{$ft$\}^\{3\}/\backslash$mathrm$\{$min$\}\backslash ),$ how much higher is the surface of the higher reservoir compared to the lower reservoir.