Anchor ads are not supported on this page.

4S Ranch Allied Gardens Alpine Baja Balboa Park Bankers Hill Barrio Logan Bay Ho Bay Park Black Mountain Ranch Blossom Valley Bonita Bonsall Borrego Springs Boulevard Campo Cardiff-by-the-Sea Carlsbad Carmel Mountain Carmel Valley Chollas View Chula Vista City College City Heights Clairemont College Area Coronado CSU San Marcos Cuyamaca College Del Cerro Del Mar Descanso Downtown San Diego Eastlake East Village El Cajon Emerald Hills Encanto Encinitas Escondido Fallbrook Fletcher Hills Golden Hill Grant Hill Grantville Grossmont College Guatay Harbor Island Hillcrest Imperial Beach Imperial Valley Jacumba Jamacha-Lomita Jamul Julian Kearny Mesa Kensington La Jolla Lakeside La Mesa Lemon Grove Leucadia Liberty Station Lincoln Acres Lincoln Park Linda Vista Little Italy Logan Heights Mesa College Midway District MiraCosta College Miramar Miramar College Mira Mesa Mission Beach Mission Hills Mission Valley Mountain View Mount Hope Mount Laguna National City Nestor Normal Heights North Park Oak Park Ocean Beach Oceanside Old Town Otay Mesa Pacific Beach Pala Palomar College Palomar Mountain Paradise Hills Pauma Valley Pine Valley Point Loma Point Loma Nazarene Potrero Poway Rainbow Ramona Rancho Bernardo Rancho Penasquitos Rancho San Diego Rancho Santa Fe Rolando San Carlos San Marcos San Onofre Santa Ysabel Santee San Ysidro Scripps Ranch SDSU Serra Mesa Shelltown Shelter Island Sherman Heights Skyline Solana Beach Sorrento Valley Southcrest South Park Southwestern College Spring Valley Stockton Talmadge Temecula Tierrasanta Tijuana UCSD University City University Heights USD Valencia Park Valley Center Vista Warner Springs

Dying to learn about Imperial Beach/border currents

Results in from last year's tests that colored ocean pink

The surf at Imperial Beach Pier, September 23, 2015
The surf at Imperial Beach Pier, September 23, 2015

The results from the pink dye dropped into the surf between Imperial Beach and the border last year are in, and they're set to color the way we think about how sewage spills and dumped pollutants behave, according to Scripps Oceanography researchers.

"It is striking that it hugs the coast, especially when you compare it to the plume-tracker data," said Scripps grad student Derek Grimes. "The momentum the flow [of dyed water] has coming out of the river mouth can definitely have an impact, but it still hugs the shore."

Grimes presented the preliminary results at the International Water and Boundary Commission citizens forum meeting Thursday night (September 1).

Sponsored
Sponsored

The Scripps project is not focused on studying local problems so much as it is about learning the physics of how close-to-shore ocean water behaves, said Scripps assistant professor Sarah Giddings.

"The dye releases are a way for us to understand the physics," Giddings said. "Once we have a good understanding of the physics, we can actually do models that are predictive."

But for Roderick Michener, a former Surfrider official who surfs I.B. and O.B., the finding that dye hugs the coast is important — the county's array of water samplers are set up about a half mile off shore, he said.

"That means it's a mystery what's going on in close to shore. On days that the county says it's fine, things can smell bad and you come out of the water with an irritation. And on days they close the beach, the water smells clean," he said. "It's exciting to see how contaminants move so we can get to where we don't close the beach so often if the surf-line isn't contaminated."

Grimes and his crew released pink dye at three locations between September 23 and October 15 of last year: at a spot 300 meters south of the I.B. Pier, and then with the last release from inside the Tijuana Estuary river mouth. They had planned to make a fourth dye-drop in Mexico with permission from Mexican authorities but got stalled at a border-crossing backup and gave up, he said.

The other dye releases, which made for spectacular aerial photos, started out intensely pink but dissipated in about 48 hours. Dye went as far as halfway up the Silver Strand, Grimes said.

"It takes ten hours for the dye to get from the river mouth to the shores of Imperial Beach," he said. "For us, the rate at which it is spreading out is important."

On one dye release, the scientists watched the dye move north for ten hours — hugging the shore all the time; and then with wind and tide and swells changing, move back south and into Mexican waters, still hugging the shores. The factors affecting the dye movement — wind, tide, swells and air and water temperatures — are "incredibly complex," Grimes said.

The dye-releases eventually move across the surface, where the water is warmer, out to sea. But they stay close to shore longer than the Scripps team had anticipated, Grimes said. Unfortunately, there are no plans to continue the surf-line dye testing. Giddings said that the study, funded by the National Science Foundation, is aimed at learning the physics, not at studying the path of contaminants coming into the ocean from the Tijuana River and Mexican shores.

"Once we start talking about doing a local project, the funding sources shrink," she said. But, funding aside, I.B. city councilman Ed Spriggs said the project is important because it suggests that the cleanliness of the water could be measured more accurately. "This sort of data could actually limit beach closures to when it's appropriate," he said.

The latest copy of the Reader

Here's something you might be interested in.
Submit a free classified
or view all
Previous article

Issa aide collaborates with Ukrainians

Carlsbad's Tracy Slepcevic, Warrior Mom, and her ties to RFK, Jr.
The surf at Imperial Beach Pier, September 23, 2015
The surf at Imperial Beach Pier, September 23, 2015

The results from the pink dye dropped into the surf between Imperial Beach and the border last year are in, and they're set to color the way we think about how sewage spills and dumped pollutants behave, according to Scripps Oceanography researchers.

"It is striking that it hugs the coast, especially when you compare it to the plume-tracker data," said Scripps grad student Derek Grimes. "The momentum the flow [of dyed water] has coming out of the river mouth can definitely have an impact, but it still hugs the shore."

Grimes presented the preliminary results at the International Water and Boundary Commission citizens forum meeting Thursday night (September 1).

Sponsored
Sponsored

The Scripps project is not focused on studying local problems so much as it is about learning the physics of how close-to-shore ocean water behaves, said Scripps assistant professor Sarah Giddings.

"The dye releases are a way for us to understand the physics," Giddings said. "Once we have a good understanding of the physics, we can actually do models that are predictive."

But for Roderick Michener, a former Surfrider official who surfs I.B. and O.B., the finding that dye hugs the coast is important — the county's array of water samplers are set up about a half mile off shore, he said.

"That means it's a mystery what's going on in close to shore. On days that the county says it's fine, things can smell bad and you come out of the water with an irritation. And on days they close the beach, the water smells clean," he said. "It's exciting to see how contaminants move so we can get to where we don't close the beach so often if the surf-line isn't contaminated."

Grimes and his crew released pink dye at three locations between September 23 and October 15 of last year: at a spot 300 meters south of the I.B. Pier, and then with the last release from inside the Tijuana Estuary river mouth. They had planned to make a fourth dye-drop in Mexico with permission from Mexican authorities but got stalled at a border-crossing backup and gave up, he said.

The other dye releases, which made for spectacular aerial photos, started out intensely pink but dissipated in about 48 hours. Dye went as far as halfway up the Silver Strand, Grimes said.

"It takes ten hours for the dye to get from the river mouth to the shores of Imperial Beach," he said. "For us, the rate at which it is spreading out is important."

On one dye release, the scientists watched the dye move north for ten hours — hugging the shore all the time; and then with wind and tide and swells changing, move back south and into Mexican waters, still hugging the shores. The factors affecting the dye movement — wind, tide, swells and air and water temperatures — are "incredibly complex," Grimes said.

The dye-releases eventually move across the surface, where the water is warmer, out to sea. But they stay close to shore longer than the Scripps team had anticipated, Grimes said. Unfortunately, there are no plans to continue the surf-line dye testing. Giddings said that the study, funded by the National Science Foundation, is aimed at learning the physics, not at studying the path of contaminants coming into the ocean from the Tijuana River and Mexican shores.

"Once we start talking about doing a local project, the funding sources shrink," she said. But, funding aside, I.B. city councilman Ed Spriggs said the project is important because it suggests that the cleanliness of the water could be measured more accurately. "This sort of data could actually limit beach closures to when it's appropriate," he said.

Comments
Sponsored

The latest copy of the Reader

Here's something you might be interested in.
Submit a free classified
or view all
Previous article

Birdwatching bonanza, earliest sunset of the year, bulb planting time

Venus shines its brightest
Next Article

Issa aide collaborates with Ukrainians

Carlsbad's Tracy Slepcevic, Warrior Mom, and her ties to RFK, Jr.
Comments
Ask a Hipster — Advice you didn't know you needed Big Screen — Movie commentary Blurt — Music's inside track Booze News — San Diego spirits Classical Music — Immortal beauty Classifieds — Free and easy Cover Stories — Front-page features Drinks All Around — Bartenders' drink recipes Excerpts — Literary and spiritual excerpts Feast! — Food & drink reviews Feature Stories — Local news & stories Fishing Report — What’s getting hooked from ship and shore From the Archives — Spotlight on the past Golden Dreams — Talk of the town The Gonzo Report — Making the musical scene, or at least reporting from it Letters — Our inbox Movies@Home — Local movie buffs share favorites Movie Reviews — Our critics' picks and pans Musician Interviews — Up close with local artists Neighborhood News from Stringers — Hyperlocal news News Ticker — News & politics Obermeyer — San Diego politics illustrated Outdoors — Weekly changes in flora and fauna Overheard in San Diego — Eavesdropping illustrated Poetry — The old and the new Reader Travel — Travel section built by travelers Reading — The hunt for intellectuals Roam-O-Rama — SoCal's best hiking/biking trails San Diego Beer — Inside San Diego suds SD on the QT — Almost factual news Sheep and Goats — Places of worship Special Issues — The best of Street Style — San Diego streets have style Surf Diego — Real stories from those braving the waves Theater — On stage in San Diego this week Tin Fork — Silver spoon alternative Under the Radar — Matt Potter's undercover work Unforgettable — Long-ago San Diego Unreal Estate — San Diego's priciest pads Your Week — Daily event picks
4S Ranch Allied Gardens Alpine Baja Balboa Park Bankers Hill Barrio Logan Bay Ho Bay Park Black Mountain Ranch Blossom Valley Bonita Bonsall Borrego Springs Boulevard Campo Cardiff-by-the-Sea Carlsbad Carmel Mountain Carmel Valley Chollas View Chula Vista City College City Heights Clairemont College Area Coronado CSU San Marcos Cuyamaca College Del Cerro Del Mar Descanso Downtown San Diego Eastlake East Village El Cajon Emerald Hills Encanto Encinitas Escondido Fallbrook Fletcher Hills Golden Hill Grant Hill Grantville Grossmont College Guatay Harbor Island Hillcrest Imperial Beach Imperial Valley Jacumba Jamacha-Lomita Jamul Julian Kearny Mesa Kensington La Jolla Lakeside La Mesa Lemon Grove Leucadia Liberty Station Lincoln Acres Lincoln Park Linda Vista Little Italy Logan Heights Mesa College Midway District MiraCosta College Miramar Miramar College Mira Mesa Mission Beach Mission Hills Mission Valley Mountain View Mount Hope Mount Laguna National City Nestor Normal Heights North Park Oak Park Ocean Beach Oceanside Old Town Otay Mesa Pacific Beach Pala Palomar College Palomar Mountain Paradise Hills Pauma Valley Pine Valley Point Loma Point Loma Nazarene Potrero Poway Rainbow Ramona Rancho Bernardo Rancho Penasquitos Rancho San Diego Rancho Santa Fe Rolando San Carlos San Marcos San Onofre Santa Ysabel Santee San Ysidro Scripps Ranch SDSU Serra Mesa Shelltown Shelter Island Sherman Heights Skyline Solana Beach Sorrento Valley Southcrest South Park Southwestern College Spring Valley Stockton Talmadge Temecula Tierrasanta Tijuana UCSD University City University Heights USD Valencia Park Valley Center Vista Warner Springs
Close

Anchor ads are not supported on this page.

This Week’s Reader This Week’s Reader