storm water managment calcs

[blimkie.k]

I need some help dealing with storm water. I'm trying to get a site plan approved and the township engineer wants to see "calculations in the form of a storm water management brief to indicate how post development floes will be managed such that they do not exceed pre development flows for a 100 year event."

The building is 50x60 feet and the new aspalt parking area will be 500 sq metres. I have allready set slopes off the building to be 2% as well as 2% on the asphalt to the sides and ditch at the front of the lot.

A Civil Engineer wants 3,000 dollars to do a site grading and storm water managment plan. Thats too much the owner of the property is not happy because the same company allready charged him 3,000 for a topo plan.

Anyways just wondering if anyone could provide me with a link or point me in the right direction on how i could attempt these calcs.

Thanks.

[CarlAK]

I'm a Civil Enginer and have no idea what the previous responder was saying.

We would have charged you more than $3000 + $3000 to do a topo survey, produce a drawing, then a site grading plan, & stormwater calculations. To "manage" flows and not exceed pre-development, a pond or chamber along with flow controls would need to be included in the design as well. Agencies usually require these plans & calcs be performed under the direction of a qualified (licensed) individual. My advice, leave it to the professionals.