Analyze water runoff in existing water stream

[sanetdikkumbura1950]

Hi,
Areas "A" and "B" are sloped to the water stream flowing through the middle. I am planning to use pipe culverts at locations "1" and "2". I need to know if the depth of the existing stream is sufficient to keep these two areas from flooding. How can I do it using SSA or INFODRAINAGE in civil 3d? what are the work steps?
(Assuming that there is no water flow through the stream under normal conditions, we need to know whether the water in these two sections will flood during a rainfall event.)
Thank you

[matt_anderson_pe]

Just a few questions first:

Offsite flow should be considered north of point 1.   Offsite backwater south of 2 should also be considered.

There is an example "Culvert" project in SSA that you can use as your sample.  You need to know the amount of surface storage north of 1 that occurs, when the level of road side.

As for Areas 'A' and 'B' - how are you planning on getting water to the culvert?  By ditch? or storm sewer?

In most cases - we determine existing conditions (before you pave A and B) what is the streams performance across the various rainfall events.  With the addition of homes and roads, this will create additional runoff volume earlier.   How does the system overall perform?  Do we impact downstream (increase in rate) or upstream (increase in depth) that might cause issues with adjoining landowners?  Then we can determine what mitigation onside do we need to protect the homes we are developing.