Ventura County
Watershed Protection District

OST Yard Stoplogs – Canada de San Joaquin

GIS Hot Spot ID: 

159-1   OST Yard Flooding

159-2   Ventura River Levee - OST Yard Stoplogs

A cut trough the Ventura River Levee was made so the railroad could continue to access facilities further north.  Stoplogs would be inserted when there were high flows from the Ventura River.  Since the levee was built the railroad was removed and a bicycle trail was built in its place.  Also Highway 33 was elevated just to the west of the stoplog location which resulted a keeping flows away from the stoplog area except where the flows can reverse along the Canada de San Joaquin and flood the OST yard just outside the levee and the stoplog area.  The main threat currently resides from backwater along the Canada de San Joaquin due to high flows in the Ventura River.

Historical Data

The area was inundated in the 1938 floods.  This was before the levee and current configuration of Highway 33.  Since the construction of both the levee and Highway 33, there has not been any flooding that went through the levee since the early 1970’s.  The highest recorded flow on the Ventura River occurred in 1978.  The flow of 63,600 cfs was measured at Foster Park.  Aerial imagery shows some flooding along Canada de San Joaquin but the photos do not show the stoplogs in place or any inundation area that went up to the levee east of highway 33.  It is unclear if the flooding was due to Canada de San Joaquin or the Ventura River.  Minor flooding has been recorded along the Canada de San Joaquin during the storms in the 1990’s.  Reports for the owners of the OST Yard state that the flooding was due to debris caught along the bridges that backed water up and out of the channel.  These breakouts did not inundate the area next to the levee or the stoplog area.

Aerial Photo and Map

Photos of Area

Aerial photo showing the Ventura River Levee and the stoplog structure, Pictometry 2008

Special Conditions/ Issues

O&M will need time to insert the stoplogs.  Because there have not been any flooding issues at the stoplog location and the complex interaction of the hydrology, the values below are estimated using the 1978 peak as the maximum safe flow.  During any high flows on the Ventura River the situation should be watched using patrols to determine if the stoplogs should be placed earlier or delayed until higher flows.  Complex 2-D modeling may help to obtain better threshold values.  Extremely high flows would already have broken out through underpasses upstream and having the stoplogs inserted will keep the flow from advancing into the City of Ventura.

Minimal Time for Implementation

Install stoplogs at OST Yard: 3 hours (more if possible).  Need to verify with O&M

Response Time of Upstream Stream Gages

The response time between the Foster Park stream gage and the OST Yard is about 1 hour.  This means that the Hydrologist will need to depend on the model using the observed stream flow to see how the model is progressing early in the event.  If Ventura County is already experiencing saturated conditions and the model is showing the forecasted storm creating flows above the thresholds, the Hydrologists may decide to act on the model results alone.

 Normal Conditions Procedure

Gages Used:  608

 Data Source

Threshold values were estimated using historical flooding knowledge and aerial imagery from 1978 that contains the highest peak since the construction of both the Ventura River Levee and Highway 33.  Complex 2-D modeling may help to obtain better threshold values if funding becomes available in the future.