Water quality managers are able to track the offshore river discharge as ..... network, surf zone transport modeling, near real-time particle tracking tools and ...
Tracking Surface Pollutants in Southern California Coastal Waters Burt Jones University of Southern California 3616 Trousdale Parkway Los Angeles, California 90089 USA
Amanda Dillon Southern California Coastal Ocean Observing System Scripps Institution of Oceanography 9500 Gilman Drive La Jolla, California 92093 USA
Lisa Hazard Southern California Coastal Ocean Observing System Scripps Institution of Oceanography 9500 Gilman Drive La Jolla, California 92093 USA
Eric Terrill Southern California Coastal Ocean Observing System Scripps Institution of Oceanography 9500 Gilman Drive La Jolla, California 92093 USA
Julie Thomas Southern California Coastal Ocean Observing System Scripps Institution of Oceanography 9500 Gilman Drive La Jolla, California 92093 USA
Libe Washburn University of Southern California, Santa Barbara Ellison Hall 6818 Santa Barbara, California 93106 USA I. INTRODUCTION
Clean beaches and coastal waters are integral to California’s economy, environment and public health. Effective management of wastewater discharges and surface runoff is crucial to the preservation of marine life and aquatic habitats as well as the prevention of contaminated food sources, drinking water and recreational waterways. Therefore, tracking surface pollution is essential to managing and protecting coastal waters in the state. Southern California Coastal Ocean Observing System (SCCOOS) data and products will assist managers in tracking pollutants and coastal discharges, enabling more precise and timely management decisions. II. TIJUANA RIVER VALLEY PLUME TRACKING
Sewage contaminated runoff has been a major public health issue in the Tijuana River Valley and adjacent ocean beaches for decades. In San Diego County, the Department of Environmental Health (DEH) uses SCCOOS real-time surface current measurements to help predict the flow of contaminated water from the Tijuana River during rain events to aid in determining beach closures. Water quality managers are able to track the offshore river discharge as
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it flows into the Pacific Ocean using hourly trajectory maps generated by high frequency (HF) radar and animations of the plume. Plume tracking models simulate Lagrangian particles trajectories using surface velocity fields derived from HF radar data. These models are currently being evaluated for search and rescue operations, oil spill response and wastewater discharge monitoring. The Tijuana River National Estuarine Research Reserve (TRNERR) monitors water quality, weather and biotic indicators within the Tijuana River Estuary, as part of a US-wide monitoring program. One of the goals of the program is to better understand the effects of the often-polluted Tijuana River outfall on the nearshore marine environment. SCCOOS provides a “critical larger context for the information” and “data in an easily accessible format.”1 The SCCOOS online display shows the results of particle tracking model based on hourly surface currents derived from HF radar. The plot indicates the tracking of water from the mouth of the Tijuana River within the domain observed by SCCOOS. Every hour, 100 particles are released at the river mouth and tracked for three days to estimate where the Tijuana River plume may be impacting the coast. The color of the particles represents the time since the particle was released (Figure 1).
Fig. 1 Tijuana River Particle Tracking
III. HARMFUL ALGAL BLOOM MONITORING
Algal blooms occur frequently along the Southern California coastline in response to inputs of nutrients from both natural and anthropogenic sources. Some of these blooms can be harmful to the environment, human health and the economy and appear to be increasing in frequency and intensity. Certain algal species such as Pseudo-nitzschia produce potent toxins that can be transferred to organisms at higher trophic levels such as birds, marine mammals and humans. Like all components of the food web, algal blooms are part of a larger marine ecosystem driven by many complex factors including winds, currents and nutrients. Surface current mapping has proven to be an essential tool for managers and scientists to assess and respond to harmful algal blooms (HABs) and will be instrumental in developing the ability to predict the occurrence and spread of these events. The SCCOOS HAB team monitors the occurrence of harmful phytoplankton species at five pier sites: San Luis Obispo, Santa Barbara, Santa Monica, Newport Beach and La Jolla. Sampling by the group began the week of 30 June 2008 and continues weekly at each of the sites. Net tows are taken and the abundance of potentially toxic 1
Dr. Jeff Crooks, Research Coordinator, Tijuana River National Estuarine Research Reserve.
species are enumerated and reported the same day. Water samples for more quantitative cell counts are also taken and measurements include temperature, salinity, chlorophyll concentration, primary inorganic nutrients and particulate domoic acid concentration. The SCCOOS HAB monitoring team launched a “Harmful Algal Bloom and Red Tide” website that provides interactive regional maps with time series of pier samples (Figure 2), definitions of algal species, descriptions of algal blooms and news: www.sccoos.org/data/habs/index.php. The program goals are to collect comparable data at the five regional stations and provide timely updates on HAB events. These observations will increase understanding of the timing, extent and impact of these events on public health and the larger ecosystem. Specific activities of the program are to: • • • •
Monitor for specific phytoplankton and algal toxins Provide weekly online updates of potential HAB events Coordinate sampling parameters, methods and data output for monitoring HAB events and coastal water quality Contribute to the statewide phytoplankton and shellfish monitoring program for the California Department of Public Health
In the spring of 2009, the SCCOOS HAB monitoring team detected a widespread domoic acid event resulting from a Pseudo-nitzschia bloom in the waters off southern California. With pier monitoring and autonomous glider mapping, the team was able to detect the event before it became apparent at the surface. Combining measurement tools with glider observations of phytoplankton distributions, the team was able to target sampling and provide an early alert of the developing event. The early detection was announced on the California Harmful Algal Bloom Monitoring and Alert Program (HABMAP) listserv to provide a statewide alert to animal rescue centers, other users and coastal managers. In this time period, there were many marine mammal and bird strandings and deaths in the Los Angeles and Orange County areas and approximately half of the marine mammal samples analyzed tested positive for domoic acid. The SCCOOS HAB monitoring team works closely with the NOAA-funded MERHAB RADPALERT project at the University of Southern California (USC), the Center for Embedded Networked Sensing project at USC, the Orange County and Los Angeles County Sanitation Districts, the Pacific Marine Mammal Center, the Fort MacArthur Marine Mammal Care Center, the Wetlands and Wildlife Care Center, the International Bird Rescue Research Center and the investigators from the Central and Northern California Ocean Observing System (CeNCOOS).
Fig. 2 Harmful Algal Bloom Regional Map
IV. OIL SPILL RESPONSE
Once an oil spill has occurred, tracking its movement, especially in dark or foggy conditions, is the first challenge in mitigation efforts. HF radar measures ocean surface currents during the night, in fog or when conditions prevent direct observation of the spill. When the Cosco Busan collided with the Bay Bridge in San Francisco in 2007 spilling over 53,000 gallons of fuel oil, dense fog hampered containment efforts. Once news of the spill was released, surface current data were able to show the path the spill had taken and indicate where the oil would travel next. As HF radar capabilities are further integrated into California spill response, future response efforts will be greatly assisted by near real-time current data and trajectory maps of spill movement. Additionally, development of predictive tools will decrease response time and allow for better protection of critical habitats and resources both on land and at sea. On 7 December 2008, approximately 1,100 gallons of crude oil was released from a hole in a pump line in the Santa Barbara Channel. California's Office of Spill Prevention and Response (OSPR) contacted SCCOOS the following day to access HF radar data for on-scene support. SCCOOS provided HF radar derived surface current data that was integrated by OSPR into their GIS-based support products and provided to the first responders (Figure 3). Online products of wind and ocean wave conditions were also communicated to assist the marine operations. The spill was effectively contained by 9 December 2008. It occurred at the same location as the historic 1969 spill that released 4.2 million gallons of crude oil into the ocean and is often credited with initiating the modern day environmental movement. Earlier in the week, the same coastal current information was used by NOAA HAZMAT to assess the risk of 10,000 gallons of jet fuel spilled to the south of San Clemente Island by a U.S. Navy vessel.
Fig. 3 OSPR Map with HF Radar Surface Currents
SCCOOS is working with OSPR and other federal, state and local agencies to integrate surface current data and products into statewide prevention and response through large-scale, multiagency interactions. For example, CeNCOOS and SCCOOS investigators participated in Safe Seas ’06 which was a NOAA-led multiagency simulated spill off the San Francisco coast and the National Preparedness for Response Exercise Program (NPREP) simulation involving 200 agencies off the coast of San Diego in the summer of 2008, respectively. These exercises allowed the many state and federal regulatory agencies involved in oil spill response to practice working together in the event of
an actual spill. They also demonstrated the value of near real-time surface currents maps for informing spill management and decision-making. Because repeated demonstrations have highlighted the value of surface current data to oil spill response, HF radar data are now being integrated into NOAA spill response models and will improve spill responders trajectories of a spill, allowing more precise targeting of assets for containment and clean-up. An oceanographer with the Minerals Management Service writes that SCCOOS data products “greatly enhance our ability to calculate oil spill trajectories.”2 V. ORANGE COUNTY SANITATION DISTRICT OUTFALL
SCCOOS provides environmental data support to the Orange County Sanitation District (OCSD) for ocean outfall planning. SCCOOS is developing a set of products and tools that include local views of modeled surf zone waves and alongshore currents, near real-time meteorological observations and surface currents. The information generated is designed to support OCSD operations and environmental monitoring staff, regulators and the public for ocean outfall repairs and any emergency discharge into the ocean or the Santa Ana River. The Orange County Sanitation District outfall is located one mile off the coast of Huntington and Newport Beaches (Figure 4). As necessary, OCSD reduces flow through their 120-inch outfall or shuts it down completely to perform necessary maintenance, make repairs, or carry out new construction projects. In these cases discharge may be diverted through the 78-inch outfall and emergency overflow weirs to the Santa Ana River may also be used. OCSD develops detailed contingency plans for many projects involving diversions. As a part of its contingency planning for these projects which might affect the use of the 120-inch ocean outfall, OCSD will request data and product support from SCCOOS. SCCOOS has developed a set of products to support routine ocean outfall operations and any planned or unplanned diversions to OCSD's 78-inch ocean outfall or to the Santa Ana River. The following two incidents are an example of events when OCSD relies on SCCOOS HF radar currents for its planning. Outfall maintenance: 7 May 2008 OCSD was scheduled to make infrastructure repairs during a planned 120-inch outfall reduced flow condition. The repair had been scheduled to take advantage of low plant flow and low tide conditions. The repair time was limited to a three hour window. Repair work had to be carefully planned and sequenced in order to complete the repair tasks within the brief shutdown window and it was not anticipated that the 120-inch outfall would need to be shut down. Contingency measures were developed and were ready to be implemented if needed. If additional time was required, OCSD had planned to shutdown the outfall and store flow in the empty tanks and take other appropriate measures to minimize the possibility of a spill or alternate discharge to Santa Ana River or the 78-inch ocean outfall. Outfall Maintenance: 18 May 2007 OCSD was scheduled to make infrastructure repairs. Repairs occurred in the early morning during low flows and OCSD diverted and stored incoming and treated wastewater within the delivery and treatment systems during the repair. However if delays were to occur, there was the possibility of having to discharge from an emergency outfall located about one mile off the coast of Newport Beach. The operation was scheduled to begin at 4 a.m. May 18, 2007 and was completed before the peak flow period which occurs in the late morning. Basic to the understanding of the effects of coastal discharges is: routine monitoring of discharge plumes, both subsurface and surface; documenting their development over time; and ultimately, identifying locations where they transport materials such as pollutants, bacteria and nutrients. OCSD has an ocean monitoring and research program designed to look at potential effects to the coastal ocean from the discharge of treated wastewater. To identify and discriminate between impacts, there is a need to understand both the fate and transport of the pollutants discharged from OCSD’s submerged ocean outfall and possible interactions between OCSD’s drainage system and illegal dumping. Additionally, there is a need for information on how large-scale spatial and long-term current patterns affect the evaluation of these impacts. OCSD and other dischargers are partnering with SCCOOS to leverage and enhance their evaluations of coastal environmental impacts using a variety of data sources.3
2
David E. Panzer, Oceanographer, Minerals Management Service, U.S. Department of the Interior.
3
George L. Robertson, Senior Scientist, Orange County Sanitation District.
Fig. 4 Geography of the OCSD Diversion
VI. HYPERION TREATMENT PLANT DIVERSION
In November of 2006, the City of Los Angeles diverted the flow from Hyperion, its oldest and largest wastewater treatment plant, from an outfall five miles from the shoreline to a rarely used outfall one mile offshore to allow inspection of the five-mile pipe. The diversion lasted three days and approximately 800 million gallons of secondary-treated wastewater were discharged one mile off the coast of Santa Monica. Central to the execution of the event by the City’s Environmental Monitoring Division was an extensive monitoring plan designed to protect public health, comply with the National Pollutant Discharge Elimination System (NPDES) permit requirements, track effluent plume and assess any environmental impacts. Coordinated monitoring and reporting efforts by SCCOOS members including the University of Southern California, the Jet Propulsion Laboratory, the University of California, Los Angeles, Scripps Institution of Oceanography and the Southern California Coastal Water Research Project (SCCWRP) splayed a key role in the supporting the monitoring plan and providing information used to guide the City in assessing the impact of the discharge. SCCOOS provided data and products to track and monitor the discharge plume that included surfzone wave height, meteorological observations, surface currents and particle tracking as well as pier and boat-based observations. Surface current mapping was used to track and forecast the dispersion of the surfacing plume using its HF radar based particle tracking tool. Using this tool along with wind forecasts from the SCCOOS web site, the probable path of the plume was used to direct boat-based sampling each day to monitor the plume and its associated fecal indicator bacteria. Because the discharge was close to shore, the surf zone transport model was used to predict the direction of transport along the beach. Although an extended portion of the beach (10 miles of shoreline) was closed to bathers as a precautionary measure, the surf zone forecasts facilitated knowing which areas needed additional attention. The surface drifter tool from the Huntington Beach 2006 (HB06) experiment provided direct monitoring of real-time surface transport using surface drifters deployed by SCCWRP. The boundaries of the plume from conductivity, temperature, depth (CTD) data, aerial photographs (Figure 5), HF radar surface current data, drifter data and the particle model indicated that only about two to three miles of beach should have been closed as a precaution. SCCOOS developed a comprehensive project web site to provide up-to-the-minute ocean environment information for rapid access and evaluation by managers and regulators during the discharge diversion. SCCOOS also provided daily email updates to the Environmental Monitoring Division summarizing the predictions, modeling and observations that were relevant to the monitoring of the event. The information enabled Division staff to decide where to focus their in situ monitoring efforts. It also allowed the public to follow events related to the diversion.
The web site also made multiple types of observations available in one central location that was easily accessible by the agency and supporting scientists. A division manager for the Environmental Monitoring Division stated that, “the real-time current information provided through [SCCOOS] enabled us to adaptively modify our sampling grid to better track the discharge plume and to predict the dispersion of the plume.”4 The availability and performance of these resources in real-time was important to the City’s community outreach assuring the community that every effort was being made to monitor and track the plume during the diversion and was instrumental in winning the full support of the water quality regulators, beach communities, governmental agencies, other stakeholders and local environmental groups.
Fig. 5 Aerial view taken on the first day of Hyperion Diversion Photo credit: Dr. Jeroen Molemaker of UCLA IGPP
VII. CONCLUSION
SCCOOS has implemented a strong set of routine observational resources that include the HF radar current mapping network, surf zone transport modeling, near real-time particle tracking tools and consistent harmful algal bloom monitoring that provide important ongoing resources that are valuable and immediately usable for water quality issues and coastal hazards. In addition, SCCOOS has developed an ability to provide rapid response resources that include both observational tools and web resources that have provided valuable resources for clients that include coastal wastewater dischargers, oil spill response teams and government monitoring and regulatory agencies. These resources have been developed through SCCOOS’ internal collaboration and external collaborations with Publicly Owned Treatment Works, coastal regulatory and monitoring agencies and adjacent coastal observing groups, in particular CeNCOOS. These capabilities provide the ability to address very acute concerns that develop rapidly. But the long-term nature of the observations will over time enable us to address issues such as climate variability, large scale ecosystem responses and the effects of anthropogenic inputs into the coastal ocean, as well as serving these more short term events. Key to continued success in engaging users and delivering useful products will be the development of State and Federal partnerships in funding sustained operation of the observing assets.
4
Mas Dojiri, Division Manager, Environmental Monitoring Division, City of Los Angeles.
