Just a query regarding LID's in SWMM. Let's say that impervious sub-catchmant A has a total area of 100 m2.
Let's say that I deploy a LID into sub-catchment A (a rain barrel) and set its surface area as 10 m2 (thus it occupies 10% of sub-catchment in A).
In doing this, does SWMM therefore calculate the runoff from sub-catchment A using an 'adjusted' area of 90 m2?
Yes, it adjusts the non lid area, i am attaching an example model with two subs to illustrate this. The loading to the lid is the runoff from the 90 square meters + the rainfall over the LID. You can most easily see this by making the lid cover all 100 square meters.
Hi there Robert,
Thanks very much for your quick reply. OK - just another query on this. Back to my example. Let's say my 100 m2 sub-catchment (before LID) is 100% impervious. I deploy the 10 m2 LID. I select that 50% of the impervious area drains to the LID. SWMM will calculate that runoff from 45 m2 flows into the LID?
The total load to the lid will be the runoff from the 45 square meters + the rainfall.
Thanks a lot Robert.
Hey - I've got another query if you don't mind.
I've just stumbled across a strange SWMM error - for all my links, I cannot seem to view any output. I get an error "no objects to display" even though I know there is data there. Any advice? Cheers.
Under Options/Report what do you have for link reporting? do you have all links checked?