HomeMy WebLinkAboutCDP 04-52; GORSZWICK RESIDENCE; DRAINAGE REPORT; 2005-03-08CID p Of -5 ?-
DRAINAGE REPORT
FOR
GORSZWICK RESIDENCE
4237 CLEARVIEW DRIVE, CARLSBAD
APN 207-085-07
CDPO4-52
RECEIVED
PREPARED FOR JUL 072005
Erick Gorszwick ENGINEERUG
4237 Clearviw Drive DEPAME1
Carlsbad, CA 92008
PREPARED BY
Robert 0. Sukup
4322 Sea Bright Place
Carlsbad, CA 92008
March 8, 2005
GORSZWICK HYDROLOGY
The subject property is an existing single family residence on the west side of
Clearview Drive. The lot is just over 20,000 square feet. The present house and
all surface improvements will remain. No new impervious surfaces are proposed.
The owner wants to level his sloping rear yard by installing a two tiered gravity
type wall on the west side of the lot and bringing in about 400 cubic yards of dirt.
The plan for the drainage is to divide the rear yard into 4 small drainage areas,
install a drain box in each area, and have a 4" PVC pipe outlet below the gravity
walls. The outlet pipes must have a 90 degree bend at the outlet so the water is
directed down a gravel channel. The proposed gravel channels will follow the
existing gradient. The 90 degree bend will dissipate the momentum from the
exiting water and force it into the gravel drain. The 5 pound cobbles on the drain
swale with 6" of gravel underneath will function as energy dissipaters, filters and
absorption beds.
Each of the four drainage areas average 1000 square feet, plus or minus. This
equates to about .023 acres. If we use 2.5 cfs of flow per acre for estate sized
lots like this, each of the drainage areas would generate about .06 cfs for the
100 year storm. This is a very small amount of water.
The amount of water is not so much the issue as the concentration of it at
discharge points. I have designed the swales in the drainage areas with 1 %
swales. This allows for soaking of "normal" irrigation waters before they get to
the drains The 20 feet of gravel swale should take care of dissipation of exiting
Waters to a sheet flow effect without concentration of waters'.
I am comfortable that this proposal addresses the concerns of conçntced
discharges. :