$1.$ Use WinSLAMM to determine the trapping efficiency $($for TSS$)$ of the detention pond. Provide the following information:

a$.$ Parameter setups in model

b$.$ Model inputs

c$.$ Model outputs

Detention pond:

Developer wants to develop a $4$ acre site in Madison, WI$.$ Details of the site are as follows:

Existing Land UseLand use is corn straight row crops in good condition

HSG B

$100$ ft sheet flow with slope $0\mathrm{.}4\%$

$1000$ ft shallow concentrated flow with slope $2\%$

No channel flow

Proposed Site

$100\%$ impervious surfaces

HSG B

$50$ ft of sheet flow with slope $0\mathrm{.}4\%$

$1000$ ft of shallow concentrated flow with slope $2\%$

$50$ feet of channel flow in a $2$ wide by $2$ high concrete pipe

$50$ feet at slope $1\%($assume pipe is flowing full$)$

Retention pond area cannot exceed $0\mathrm{.}5$ acres. Outlet type of pond is discretion of designer.

$2.$ How does the trapping efficiency compare with the stokes law calculations completed in the previous homework? Most standards are that a development needs to achieve $80\%$ reduction in TSS $($which is equivalent to a $5$ micron particle$).$ Does the pond meet this requirement? What TSS reduction is achieved by the pond? The graph below provides some help to convert from micron size to $\%$ reduction.

Stokes law calculations:

TSSaverage$=73\mathrm{.}65$ mg$/$l

Smallest micron particle trapped in the pond $=9$ microns

Annual mass of oil v$=28,657,642$ liters

TSSannual mass$=2,113\mathrm{.}01$ kg