Southwest Pacific Coast, particularly between Santa Monica and San Diego, experienced an increase in flooding last year … similar to everywhere else.
NATIONWIDE—A National Oceanic and Atmospheric Administration (NOAA) study revealed the United States matched a record for number of high-tide flooding days for a calendar year. There were five days of high tide flooding, nationwide, in 2018 – matching a similar phenomenon in 2015.
NOAA reported there were at least 40 locations where annual rates of high tide flooding were rapidly increasing, while 25 other areas were also experiencing an increase but at a less than alarming pace.
“In all, 12 individual locations broke or tied their [high tide flooding] records. There are now over 40 locations whose [high tide flooding] trends reveal significant acceleration (nonlinear increase) and 25 locations whose [high tide flooding] trends are linearly increasing, implying that impacts soon will become chronic without adaptation,” authors of the NOAA study stated.
Flooding and sea level rise could, due to El Niño, continue to be factors in various locations before the end of 2019, according to the NOAA study.
San Diego could experience as many as five to nine days of high tide flooding in 2019, according to the NOAA study. The same study projects one to four days of high tide flooding in the Los Angeles region.
The situation could be direr on the East Coast, NOAA predicts.
“Projected frequency increases in [high tide flooding] are especially problematic in many of the older, low-lying East Coast cities that were built just above average highest tides. As sea levels have risen over the last century, stormwater systems are no longer able to perform as designed,” authors of the NOAA study stated. “[High tide flooding] causes tidewater to fill stormwater pipes, which prevents rainwater from entering storm drains and causes increased impacts from flooding. Many of these gravity-driven systems are ceasing to function as designed, causing rainwater to flood streets and neighborhoods until the tide lowers and water can drain normally.”
The frequency of high tide flooding in the Southwest Pacific is between four to seven days and 10 to 30 days, between 2030 and 2050. The Northeast Atlantic, by comparison, is expected to experience 15 to 25 days of high tide flooding in 2030 and 40-130 days of high tide flooding by 2050.
High tide flooding is expected to occur at least twice in the Southwest Pacific region in 2019, an 80 percent increase since 2000.
“Annual flood records are expected to be broken again next year and for years and decades to come,” authors of the NOAA study stated. “Projecting out to 2030 and 2050 provides vital information for communities who are already taking adaptation steps to address coastal flooding impacts and those who are beginning to assess future flood risk in their communities.”
NOAA also project we will experience seven to 15 days of high tide flooding, nationally, by 2030 and 25 to 75 such days by 2050.
The federal agency relies upon 200-plus permanent water level stations in the Great Lakes and along various ocean coastlines to gather data on potential coastal flooding and sea level rise.