Determine the lateral and main pipe sizes for a subsurface drainage project as described below. A landscape area with clay loam soil is to be drained by subsurface tiles. Twenty sections of drain tiles are to be buried $6$ ft deep and at $20$ ft spacing. Each drain tile is $200$ feet long following a $1\mathrm{.}5\%$ slope toward the main pipe. The soil has a saturated hydraulic conductivity of $0\mathrm{.}2$ in$/$hr$.$ If the top $12$ inches of soil is drained to field capacity, what is the estimated drainage coefficient? What should be the size of lateral tiles $($n$=0\mathrm{.}015)?$ Assuming the main drain uses a uniform size for the length of $400$ ft at $1\mathrm{.}5\%$ slope, what should be the size of main pipe?