CSIDE graduate student Derek Grimes and co-PI Sarah Giddings attended and presented at the International Boundary & Water Commission Citizen’s Forum on 1 September 2016. Grimes showed preliminary results from the CSIDE project which was highlighted in the local news.
Members of the UCSD/SIO Prather aerosol team joined our project looking for dye in the air… so far the results are VERY exciting! The red box in the pictures below sucks in a bunch of air condensing all of the air-borne water droplets into a sample.
Our 3rd dye release was 12 October and we sampled through 13 October. It was the most ambitous release yet. We pumped 30 gallons of dye into the Mouth of the Tijuana River Estuary on an ebbing tide over 2 hours. Rob was leading the dye release and here he is at the estuary mouth as dye is flowing:
We had shoreline instruments from 3 km south of the border in Mexico all the way up to Coronado. We had a boat from CICECE/UABC and 2 SIO boats + jetski in the water and of course the plane. The dye raced out of the inlet and headed north along the beach toward the end of seacoast drive. It then started to peel offshore in large bands. It was very impressive particularly with how good the waves were. The hydrodynamica project got some great pics – see: https://instagram.com/p/8wCx3iCcvN/?taken-by=hydrodynamica
Eventually, the dye spread further offshore in a large plume with a variety of bands moving north along seacoast drive and the shoal of the Slough offshore.
But by the end of 12 Oct it never really went north of the IB pier. See the photo below.
We released dye just north of the IB pier in the early morning hours of October 8th and tracked the dye for 2 days. The dye shot northward in response to a strong southerly swell driving strong northward currents. At first it was confined to the surfzone, after which it was confined to an alongshore band just outside of the surfzone. By the second day, dye was all the way up to the entrance to San Diego Bay (but in very low concentrations). Further south it was not at the surface, but it was found near the bottom! Very exciting data that we are looking forward to diving into. Here are just a couple of photos, more to come soon.
We have successfully concluded our first dye release experiment. The preliminary observations are promising, as we have comprehensive measurements of what turned out to be a spectacularly dynamic behavior. The raw standalone fluorometer data is substantive. The figure below illustrates the alongshore extent of the dye plume within the surf-zone. Thank you, to the numerous agencies that made these releases possible, keep our people and the public safe, and helped us coordinate a successful first mission! Thank you also to everyone who helped out: UCSD undergrads, lifeguards, and volunteers. We really appreciate all of you guys –without whom, such an extensive experiment is impossible–and we look forward to working with you in the surf during the two remaining releases.
Now this dye release was interesting because as we released dye at 5am, the surfzone currents carried the dye northward. Although some dye continued to go north, a lot of dye starting pooling around the IB pier and leaking offshore by 8am (see image above). Then the wind really started to blow out of the NW driving the surface waters to the south. This ended up splitting the dye plume in two. One part continued in the surfzone to the north – albeit at low concentrations that made its way all the way to Silver Strand State Park where SA1 was located. The second part starting flowing to the south and got stretched out dramatically in the alongshore. However, an intrusion of northward flowing water south of seacoast drive kept the dye plume from attaching to the shoreline. The two water masses may have been different inhibiting mixing? Very interesting and we are looking forward to more.
We have been checking on the instruments in the Tijuana Estuary weekly as they become entangled in kelp and covered in mud quickly!
This GPS dog collar system is typically used by hunters (among others) to follow their furry friends on the hunt. We have customized them to help us track the dye overnight, when boat, jet ski and airplane operations are suspended. Four drifters (smurf, snork, bugs, and daffy) will be deployed on the periphery of the dye plume before dark, and we will use the hand-held tracker to find them the next morning to direct resumption of our samples. Below are a few photos of the process.
On September 17th, we tested out some of our boat-based instrumentation which is used to sample currents, salinity, temperature, and dye in transects offshore. Some pictures from those tests are here:
REMUS – Remote Environmental Monitoring UnitS is an autonomous underwater vehicle that swims in a pre-programmed mission to sample the water currents, salinity, temperature, and dye concentration. Here you can see us testing out REMUS the week before our first dye release on September 16th! Things did not quite go as planned as you can see…