The U.S. Army Corps of Engineers (COE) released approximately 10,000 cfs from Prado Dam during all or portions of seven days from January 11^th, through January 17^th.  This is the highest release ever from Prado, with the previous maximum being 5,900 cfs.

 On January 20^th, the COE lowered the Prado outflow to approximately 100 cfs to allow for an in-channel topographic survey over the SARI line and visual observation of erosion at manholes and pipeline crossings.  The results of the visual survey indicate additional erosion has occurred around the SARI facilities.  On a positive note, the two grade stabilizers installed in November – December 2004, appear to have performed as expected.  However, the channel widened at these locations requiring extension of the grade stabilizer to the new channel limits.  Erosion was noted at several manholes with the most significant erosion occurring around Manhole 1078 and the access road to it.  It was further noted that river flow topped Manholes 1097, 1127, 1152 and 1203. However, the manhole lids are bolted and the pre-cast concrete sections strapped together with stainless steel straps.  It appears these measures prevented significant manhole damage and river water inflow.

As a result of the high releases, SAWPA is proposing the following actions. These actions are being coordinated with OCSD for development of the emergency repairs to be implemented immediately:

Emergency Repairs
Extend existing “SAVI Ranch” and “Coal Canyon” grade stabilizers to the limits of the wider flow channel.  “Key in” the stabilizer and provide some slope armoring.  The intent is to contain any future 10,000 cfs release within the existing channel width.

Provide additional rip-rap protection at Manholes 1078, 1089, 1097, 1132, 1152, 1165, and 1172. Restore access roads including two channel crossings as required only to complete repairs; further repairs to be completed this summer.

Additional work is also required at the following manholes, but is not deemed to require emergency repair:  Restore manhole access roads to each manhole; provide additional rip-rap protection around Manholes 1105, 1117, 1127, and 1203.

Maintenance of Access Roads and Manholes
OCSD has executed a contract with Jamison Engineering to perform manhole access road repairs and vegetation maintenance, and place rip-rap around several manholes.

The following is a listing of the work to be performed:

1. Re-grading of existing roads and installation of road base at six sites.

2. Rebuild access roads using 2” to 6” rock and approximately 30 boulders to stop winter erosion when river swells during high flow conditions at two sites.

3. Place boulders for manhole protection at three sites.

4. Repair storm drain crossing on access roads at two locations.

5. Vegetation cut back and removal at all locations.

6. Biology services during execution of work, before and after surveys, and documentation.

OCSD directed Jamison Engineering to restart this work in late December after completion of the two grade stabilizers, but the work has been placed on hold due to the high Prado Dam releases.

Emergency Response Plan (ERP)
On January 24th, SAWPA conducted a “lessons learned” meeting with SARI stakeholders. The purpose of the meeting was to capture thoughts on what worked well and areas for improvement.  It is anticipated the ERP will be revised to incorporate the ideas identified at the meeting.

To view a white paper on SAWPA's emergency response efforts click here

To view current conditions of repair areas click here. 

For recent information on flows being allowed through Prado Dam, please click on this link to the COE web site.

For additional information please contact Rich Haller at 951-354-4240.

Copyright: Santa Ana Watershed Project Authority, 2002
Last modified 10/10/2007