Monday, February 20, 2017

Matilija Dam, after the storm...

Matilija Dam, Feb 18, 2017
flow  3,500+ cfs

2-day rainfall totals Feb 18, 2017

The storm of Friday, February 17, 2017 delivered 9-10" of rain to the Matilija Canyon watershed.  Flows in Matilja Creek peaked at 4pm with approximately 7500 cfs (cubic feet per second) flowing over the dam.  The Ventura River at Foster Park peaked over 20,000 cfs later that evening.   

The hydrograph below shows flows in Matilija Canyon exceeded 3000 cfs for more than 48 hours.  This is the perfect scenario for flushing the fine sediments from the reservoir to the ocean, as required in order to physically remove the dam.  (See Matilija Dam stakeholders select local project)

Hydrograph for February 2017 storm showing flows at
Matilija Canyon and Ventura River at Foster Park
USGS Current Conditions for USGS 11118500 VENTURA R NR ...
Studies completed last year determined that the minimum high flow event on Matilija Creek that is assumed to be able to transport the large quantities of fine sediment over a short period of time is a storm having an average daily flow of at least 1,700 cfs, corresponding to a peak daily flow of about 3,000 cfs (Stillwater Sciences, 2014b). This is approximately a 4‐year recurrence interval on Matilija Creek.

Although much work remains until the project is ready, a storm like this will exceed that required for the eventual removal of Matilija Dam.

In the News:

“What it really demonstrates is the tremendous energy that the Ventura River has when we get these types of flood events,”

On this blog:


Matilija reservoir upstream of the dam, Feb 18, 2017
The main flow currently enters the reservoir along the right bank (far side in this photo)

contrasting graffiti decorates the obsolete Matilija Dam