Monday, January 02, 2017

The Harbor Report: Learning about sea level rise and flooding in Newport Harbor

Professor Brett Sanders of UC Irvine
By: Len Bose

I recall at the age of 5 attending a party at my Aunt Pauline's when I decide I wanted to join everyone in the pool. I just jumped in and ended up at the bottom of the deep end.

My father quickly came to my rescue, brought me to the surface and then started telling me how proud he was of me jumping in way over my head. I also remember it taking another year for me to ever leave the ankle and waist-high kiddie pool after that.

Why this story comes to mind while interviewing Professor Brett Sanders of UC Irvine in his lab at the Civil and Environmental Engineering building is beyond me. I guess it must be the fact that I was jumping in over my head again and was interested in learning more about sea level rise and flooding in Newport Harbor.

I happen to live in Huntington Beach in the low lying topography of the Santa Ana river flood plain, so this too sparks my interest in sea level rise.
Adam Luke

This story is not alarmist and I haven't started to build a replica of Noah's Ark. One of the first things I learned was that over the next 30 years there is about a 1% chance, in any given year, that we will see ankle or waist-high flooding around Newport Harbor.
Sanders and his team are working hydraulic modeling and 3-D mapping of the entire Newport Harbor Bay system, with the goal of creating a harbor-wide picture of what flood events can do. Two other members of Sanders' team, Jo Schubert and Adam Luke, attended the interview. In the new year there will be a website that the public can access and examine all the different features these maps will offer.
Jo Schubert

"We will be providing a tool that will bring the risk down to a household level and help communities to be better prepared for and manage flooding," Sanders said. "Decision-makers will benefit from a variety of different maps, depths and water movement."
One of the most interesting aspects of developing this model is how all the local information was gathered. A public door-to-door field survey was taken asking people where they have seen flooding in their neighborhoods.
Different city agencies were contacted and surveyed, including the Public Works, fire, sheriff and police departments.
"If you bring scientific experts together with local expertise and you allow them to work together to characterize the problem you get a tool or model that is scientifically credible and trusted by the community," Sanders said. "The need for flood-vulnerable communities to engage in a better conversation in flood resilience is imperative."

These maps will be used in a number of different ways. For example, flood risk mitigation plans can be made with regard to raising sea walls, raising homes' foundations, and making sandbags and sand berms. This will give homeowners the ability to better understand the risk of low-level flooding.
It will also more time to prepare by revealing the location, depth and strength of the flooding before it happens.
After flooding occurs these maps will help people understand which areas have been impacted, which are under water, blocking roads and how the community can rebuild. This model is a tool to help make decisions, allocate resources and manage risk.


Flooding around Newport Harbor can be triggered in many different ways. Upland flooding can be caused by a large amount of water flowing out of the San Diego Creek channel and into the neighboring floodplain. Around Newport Harbor, flooding is caused by high embayment water levels that result from a combination of high tides, positive ocean level anomalies from storms and/or inter-annual phenomena such as El NiƱo, and streamflow from San Diego Creek. The most severe flooding occurs with coinciding river flow, rainfall, high tides, sea level raise and waves.
Extreme events have cycles and I'm sure most of you recall the floods in 1983 and 2005.


"There is room for optimism, especially looking at the data over the last 20 years it looks like we are not approaching the extremely high sea level scenario," Luke said. "We are more like the medium to lower range scenario."
After coming out of this interview I still felt like I was the kid that was plucked out of the bottom of the pool and that I was way over my head in trying to understand all the information that was given to me over the last 90 minutes.
On the other hand I felt good that I had engaged the topic of flooding in our harbor and will do my best to pass this information on to my family and friends.

Boat name of the week: La Marea Alta.
Sea ya!


LEN BOSE is an experienced boater, yacht broker and boating columnist for the Daily Pilot.

Comments from readers:

Great article Len! We need to gently goad our politicians to be concerned about, and act to ward against looming dire predictions of the distant future while being totally engrossed with immediate daily distractions. We used to have a saying in construction - "When you are up to your ass in alligators it is easy to forget that the job on hand was to drain the swamp".
Keep up the good work!

Jim (Jamshed) Dastur



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