c$.$ Given the predetermined geometry provided in the problem statement, draw a schematic of the lahydfill and then determine its total volumetric capacity. $($Hint: you may estimate the geometry of the landfill cap as a square pyramid, and the pit as a truncated square pyramid, where $V=\frac{1}{3}h(a^2+ab+b^2).)$ Compare this geometric volume with the volume requirements of the community $($from part b$)$ to determine the life of the landfill $($in years$).(+20)$

Answers: Note that the following values assume that $10\mathrm{.}5$ feet are available for the pit depth $(1\mathrm{.}5$ ft is taken up by the clay liner and the leachate collection system$).$

$V_{\text{p}\text{i}\text{t}}=811,577y{d}^3$

$V_{\text{c}\text{a}\text{p}}=4,962,312y{d}^3$

$V_{\text{t}\text{o}\text{t}\text{a}\text{l}}=5,773,888\mathrm{.}5y{d}^3$

Landfill life $=30$ years

Geometry: $,$ Available area for landfill $=50$ acres $(1476ft$ by $1476ft)$

Depth to water table $=20$ feet

Pit side slope $=1$:$3($i$.$e$.,1$ vertical : $3$ horizontal$)$

Final surface slope $=1$:$4$