Zone 4

SANTA PAULA 

RAINFALL ENDING 08/14/2018 21:11 PST

Santa Paula - Wilson Ranch
15-min Total: 0.00"
30-min Total: 0.00"
1-hour Total: 0.00"
2-hour Total: 0.00"
3-hour Total: 0.00"

Evacuation Status: No Evacuations at this time

 Rainfall Intensity Required to Generate a Debris Flow

Light rainfall following a wildfire is essential for the regrowth of vegetation. However, high-intensity rain is detrimental to the watershed and may be devastating to properties and lives in its path.

.50” of Rainfall Per Hour

  • Intensity sufficient to produce flooding/debris flows
  • Voluntary evacuation orders may be issued
  • Roadways may be restricted or closed
  • Residents with access & functional needs should leave early

.75” of Rainfall Per Hour or More

  • Sustained intensity will cause flooding and debris flows that may result in injury or death
  • Mandatory evacuation orders will be issued
  • Roadways will be affected and may be hazardous
  • Abide by recommended actions issued by authorities

Known Hazards in Zone 4

  • Flooding – Santa Paula Creek and Orcutt Canyon. (This usually doesn’t affect us in the City other than egress and ingress if it flows over Highway 126 at Orcutt Rd.)
  • Isolated Slope Failures into yards for houses on west side of 150. (In the past there are four areas that have created issues: 1) Harvey Drive home at the end of the cul-de-sac get flooded and the hillside has slid at least twice, 2) Fuchia Drive has had heavy mud and water flowing at the homes in the 1000 block, 3) April Lane has flooded out usually from the mud flow from Cherry hill Rd, 4) Stonegate Rd floods out at the entrance due to mud flow from Cherrhill Rd and North Ojai Rd.
  • Slope failure / debris flows onto HWY 150.(This is referring to North of the City in Highway 150)
  • Bank failures from high flows in Santa Paula Creek (Usually affects the properties that back up to the creek bed on the Eastside of 150, west side of the creek)
  • Slope failures / Debris Flows in Orcutt Canyon. (Same as Number 1)
  • Fagan Canyon debris basin – (Can become filled to capacity with debris and begin to backup and overflow down the Fagan barranca and affect Santa Paula Street as well as Main Street.)
  • Adams Barranca – (Heavy Water and mud flow, has flooded the trailer park on Beckwith and Telegraph Roads as well as Highway 126.
  • 12th Street, from Santa Paula street to Santa Barbara Street gets flooded under about 2 feet of water near the railroad tracks.
  • South of Highway 126 Santa Maria corridor gets flooded as presented from the last rain storm. All the drains from the North side dump straight into Santa Maria street. There are no underground drains in this area to the river bottom.
  • Santa Paula airport has had issues due to extreme water flow in the Santa Clara river. The Army Corp of Engineers completed a lot of work there and on Santa Paula creek so unknown how it will hold up.

What is a Debris Flow?

 A debris flow is a mass of loose mud, sand, soil, rock, debris, and water that travels down a slope under the influence of gravity. To be considered a debris flow, the moving material must be loose and capable of flowing. The following environmental conditions must be present to generate a debris flow:

Steep Slopes

Ventura County has an abundance of hills and mountains that make up our watershed. In a post-fire condition, these slopes provide a perfect environment for Mother Nature to develop debris flows.

Loose Debris

Following the Thomas Fire, various types of loose debris remained including burned plant material, ash, and physical property.

Source of Moisture

Rainfall more than .50”/hour can collect within a watershed and gain speed as it travels down steep slopes. As the water gains speed, loose debris is picked up and carried with the flow of water. Within channels, this water and debris mix to produce a thick flow of material.

Sparse Vegetation

Due to recent wildfires, vegetation in our local hills has been destroyed or is no longer present in many areas. Vegetation can reduce raindrop impacts to the soil because the plant roots help to hold the soil material in place.

Watershed Recovery Takes Time

Following a significant wildfire, damage to the local watershed includes the destruction of vital vegetation and root structures responsible for water absorption during a rain event. These plant materials burn and seep into the top layer of soil forming an impermeable layer of dirt also known as the hydrophobic layer. This soil layer prevents rainfall from easily penetrating the ground, particularly during high-intensity events. The remaining ash and burnt material is swept away by the rainwater and washed into nearby creeks, streams, and drainages.

On average, it takes 3-5 years for vegetation to re-establish itself to a point where water absorption and soil stabilization returns to the pre-burn condition. Nearby properties remain at increased risk for flooding and debris flows for 1-3 years following a wildfire.

How to GET READY

If you live in a flood-prone area, consider making permanent changes to your home such as constructing retaining walls and raising your furnace and electrical panel above potential flood levels.

  • Assemble an emergency supply kit as recommended by the American Red Cross.
  • Register your phone number(s) at www.vcalert.org so you can receive emergency messages.
  • Consider purchasing flood insurance. Many homeowner’s policies do not cover flood damage.
  • Create a list of items to take with you if you are asked to evacuate. In addition to your emergency supplies, consider items such as: keys, cash and credit cards; photos; insurance papers; computers; prescriptions; and pet supplies.
  • Clear debris from roof gutters, downspouts and drains so water can flow and drain properly.
  • Have a supply of sandbags and other flood prevention materials such as plastic sheeting, plywood and tarps.
  • Check the roof for leaks or damage. Pay special attention to areas where separation could occur, such as around the chimney.

 How to GET SET

  • Gather emergency supplies, evacuation items and review evacuation routes in case you are asked to evacuate.
  • Be aware that flash flooding can occur during periods of heavy or extended rain. If conditions warrant, take action immediately and evacuate the area.
  • Fill the gas tanks in your vehicles.
  • Bring in outside furniture that could be carried away by floodwaters.
  • Move furniture and other valuables to high points – upper floors if possible – in your home.
  • Fill and place sandbags if necessary.
  • Monitor gutters, drains and other areas that could cause flooding.

Sandbags

Properly placed sandbags will redirect water, mud and debris but they will not completely seal out water. Sandbags should be used for low-flow protection (up to about two feet). The following locations will stock a limited supply of sandbags for Santa Paula residents:

  • Mill Park  parking lot Ojai Santa Paula road
  • Santa Paula Community Center rear parking lot behind Fire Station 82