From: Lau, David W
Sent: Tuesday, December 20, 2005 4:55 PM
To: Brooks, Desley; '';
''; Ward, Ron (PWA); Osalbo, Faustino Jun;
Godinez II, Raul; Sweiss, Fuad; Neary, Mike
Subject: RE: [Friendsof2Creeks] Leona Quarry permitting problems

To all:

In order to treat the maximum amount of storm water through the filtration system prior to releasing to the storm drain system,  Desilva Gates (DSG) has continued its best management practice that was employed last year to increase the storage capacity of the detention pond by raising the opening of the concrete outflow structure with a temporary plywood weir .  Leona Quarry received a total of 2.96 inches of rain from last Saturday night through Sunday morning. Due to the amount of water entering the pond in such a short period of time, the water level at the detention pond rose six feet above the temporary weir on Sunday morning.  As a result of the water pressure, the temporary plywood weir failed causing a sudden release of water from the detention pond.  In addition, the erosion control fabric at the southern part of the upper slope was damaged due to a clogged inlet.

DSG has repaired the damaged erosion control fabric and is currently working on replacing the plywood weir with a steel weir in preparation for the upcoming rain storm.  According to the received e-mails from the property owners along Chimes Creek, there were damages to some private improvements including two foot bridges. 

We have directed DSG to make contacts with the private property owners.    

If you have any questions, please feel free to contact me at 510-238-7131  

David Lau, P.E.
Public Works Agency
Project Delivery Manager
(510)238-7131 (Voicemail)
(510)238-2085 (Fax)