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1.34 -C- Will the capacity of the new horizontal bored curb line be adequate to accept the simultaneous flow from 10 to 12 FDD sump pumps?

Posted by Lori Byron on 20 Dec, 2013
Category: Category 1 - SSWWEP Questions and Presentations

Frank Burdick’s Log Number: 77
Submitted by: Burdick’s Log
Category (1,2,3): 1
Status: Closed
Estimated date to address: January 16, 2014

Q. OHM has indicated that the October 31, 2013, flow test performed on the horizontal bored curb line included 5 total FDD homes. It has also been stated that the location of many existing catch basins is such that only a limited number of homes (5,6,7,8) are connected to the new curb line before being discharged into the nearest catch basin. On Winsted Blvd, there is only one catch basin to handle the entire cul de sac. There are 10 to 12 homes per each side of the street. Will the capacity of the new horizontal bored curb line be adequate to accept the simultaneous flow from 10 to 12 FDD sump pumps? 

See COMMENT below:

Comments

Lori Byron on 13 Feb, 2014:

[CITY]

There are 4 separate curb drains installed on Winsted to serve the existing homes located along this street.  The curb drains on Winsted were installed with the intention of serving no more than 5 homes per curb drain. However, using the average peak flow of 4 gpm per home, a curb drain pipe at minimum slope (1%), can serve 68 homes (see below).  If we use a sump pump maximum discharge rate of 30 gpm, a curb drain has the capacity to serve 9-10 homes.

-Pipe capacity for a 6” diameter HDPE at 1% slope, capacity is 0.61 cfs.

-Peak FDD production for 1 single-family FDD = 4 gpm = 0.009 cfs

-Maximum FDD equivalent for each curb drain run = curb drain capacity / peak FDD production = 0.61 cfs / 0.009 cfs = 68 single-family FDDs. 

Frank Burdick on 24 Feb, 2014:

F. Burdick willing to correct the record.

This past weekend 22Feb14, in an effort to help neighbors clear ice from the street and to allow surface water to flow to the catch basin, I discovered that there was, in fact, a grated cover over 2 additional catch basins on my street.  In the above question, I indicated that there was only one catch basin to serve the entire street containing 9 to 10 homes per side, (or approx 20+ homes.)

This was a mistake. There are 3 catch basins to serve the entire street. The additional two are flush to the slab (not open curb face) and located in 2 driveways at the mid point of the length of the street.  They all flow out to one exit pipe and this has been surcharged during heavy storms.

I am correcting my statement accordingly.  I question why the City did not research this and respond months ago.  I am also looking for the City to, follow this example, and correct the record on other necessary facts that may have not have been properly researched and reported to the cac.

Lori, please re-open, or re-post this to all of the cac.

Thanks