Outfall System

stormwater treatment controls


A series of outfalls on the beach adjacent to Scripps Institution of Oceanography discharge seawater back to the ocean. Because the ocean adjacent to Scripps Institution of Oceanography has been designated as an Area of Special Biological Significance as well as a Marine Protected Area, UC San Diego takes special precautions to ensure that these outfalls do not contain pollutants.

Scripps Institution of Oceanography uses an open seawater system to support its on-site research and aquaria activities. The open seawater system currently supplies approximately 500,000 to 750,000 gallons per day of seawater to laboratories and aquaria. The seawater is ultimately discharged back to the ocean via outfalls.  Scripps Oceanography has five permitted outfalls, four of which discharge seawater and one that discharges storm water in accordance with the conditions and provisions of a National Pollutant Discharge Elimination System (NPDES) permit. These outfalls discharge into the San Diego-Scripps Area of Special Biological Significance, located just north of the San Diego-La Jolla Ecological Reserve.

The five outfalls are located as follows: 

  1. Outfall 1 is located approximately 500 feet north of Ellen Browning Scripps Memorial Pier and discharges approximately 470,000 to 700,000 gallons per day of seawater that has circulated through the Birch Aquarium at Scripps, Hubbs Hall research aquaria, and NOAA Southwest Fisheries Science Center aquaria.  
  2. Outfall 2 is a stormwater outfall located approximately 240 feet south of Ellen Browning Scripps Memorial Pier, immediately downstream of two urban runoff filter treatment systems. This outfall discharges storm water only, with no facility seawater connections. Flow from this outfall is based on storm conditions.
  3. Outfall 3 is located underneath Ellen Browning Scripps Memorial Pier and discharges approximately 80,000 to 360,000 gallons per day of seawater from the Experimental Aquarium and intermittent discharges from three seawater storage tanks when a tank is drained for maintenance (approximately once or twice a year per tank).  
  4. Outfall 4A consists of two separate pipe outlets located approximately 40 and 75 feet south of Scripps Pier, underneath a patio area. Outfall 4A intermittently discharges between 10,000 to 19,000 gallons of intake seawater several times a year when the settling tanks are switched or a settling tank is drained for maintenance. The intake seawater is pre-treated through a sand and debris drum filter system located on the pier.   
  5. Outfall 4B is located approximately 25 feet south of Scripps Pier and north of Outfall 4A.  This outfall discharges back-flushed seawater from the sand filtration system. The system filters seawater pumped from the end of the Scripps Pier and is back-flushed when pressure in the system exceeds the set safety threshold. The discharges are intermittent and may be back-flushed more frequently if the turbidity of the ocean is high such as during storms and when there are algae blooms.   

Scripps Institution of Oceanography is committed to meeting clean water standards to protect the beneficial uses of the San Diego-Scripps Area of Special Biological Significance and to comply with the conditions of the NPDES permit. Seawater that is used in aquaria that contain non-indigenous species or genetically modified organisms is treated prior to discharge. These treatment systems consist of a combination of filtration, ultraviolet sterilization, and, in most cases, ozone disinfection.  If a medication is used in an aquaria to treat an animal or a chemical is added to the seawater, the seawater from that system is discharged to the sanitary sewer system in accordance with City requirements.  

Questions about the UC San Diego outfall system can be directed to Kimberly O’Connell with Environmental Health and Safety at koconnell@ucsd.edu