Wednesday, January 10, 2018

Post fire storm event, Jan 9 2018

Flows over Matilija Dam following Thomas Fire, Jan 9, 2018, 8 am

January 9, 2018 Storm totals 
On January 9, 2018, the watershed received a significant storm following the Thomas Fire.  The bulk of the rain fell overnight and early in the morning of January 9.  Fortunately the highest intensity rainfall  missed our area and did not result in the widespread destruction seen up the coast in Montecito.  Forecasters had predicted up to 9" in the mountains, whereas we actually received 5-6" with only 1-2" in the lower elevations.

While many of the county gages appeared to have been damaged, USGS was out surveying at Foster park during the storm (red stars on hydrograph.)  Peak flows at Foster Park were over 10,000 cfs, with perhaps 6,000 cfs originating from Matilija Canyon.  The hydrograph shows the effect of heavy rainfall around midday which bumped the flow back up.
The water during initial runoff was very black, as expected with all the ash from the fire.  The river remained very dirty into the evening hours.  

Ventura River looking downstream from Hwy 150 bridge, Jan 9 2018 at 3pm
Ventura River at Santa Ana bridge, Jan 9 2018 at 12pm

Ash and turbid flow, Ventura River Preserve Jan 9, 2018

The storm cleared rapidly in the afternoon, producing striking rainbows throughout the valley.

Clearing storm over the Ventura River at Hwy 150, Jan 9 2018, 3 pm

Suspended sediment from the erosion of the burn area persisted in the river for the next few days.  Fine sediment deposits along the riverbank can be seen in the photos below.

Confluence with San Antonio Creek, Jan 10, 2018

Casitas Springs Levee, Jan 10, 2018
Casitas Springs Levee, Jan 10, 2018

FosterPark, Jan 10, 2018

Foster Park bridge looking downstream, Jan 10, 2018

Foster Park bridge looking upstream, Jan 10, 2018

And of course, it all runs out to the ocean...

C-St webcam Jan 10, 2018