Question $1.$ A wet basin in a new development in Ottawa is proposed to meet municipal requirements

for a $10-$ha square drainage area composed of a single$-$family residential development at densities of $5$

and $10$ lots per hectare $(2$ and $4$ lots per acre$).$ The basin is designed to control the $2$ and $100$ year $-24hr$

storms as well as to design for water quality treatment.

The entire site currently drains to a single receiving stream located at the SW corner of the

drainage area;

Existing land cover consists of the top $2$ ha in woods $($light underbrush$)$ and the bottom $8$ ha in

brush $($dense underbrush$).$ Consider the first $25m$ to be sheetflow.

Land use under post development conditions consists of $1\mathrm{.}0$ ha of parkland, $5\mathrm{.}0$ ha of $0\mathrm{.}1-$ha single$-$

family residential lots and $4\mathrm{.}0$ ha of $0\mathrm{.}2-$ha single$-$family residential lots. The controlling flowpath

consists of $50m$ sheet flow $($grass$)$ followed by $60m$ of grassed waterway then $474m$ of paved

gutter.

The site consists of Hydrologic Soil Group D soils $($NRCS Soil Survey$)$;

$,$ Stage$-$storage relationship is $V=0\mathrm{.}5h^{1\mathrm{.}1},$ where $V$ is in acre$-$ft and $h$ is in $ft$;

Use a $100ft$ corrugated pipe for the discharge with $-2$ ft centreline and dead storage of $2ft$;

Post development the site will consist of $60\%$ impervious surfaces $($for WQV calc$)$; and

Design orifice discharges for the WQ$,$ Low Stage and High Stage events.

Prepare a schematic of the outlet structure

Hints: Use IDF Curves to determine design Precip values $($from MTO website$).$ Use $30-$year climate

normal precipitation and days of rainfall $>5mm($April $-$ Nov$)$ to determine the weighted average runoff

producing rainfall.