Landsat-8 images of chlorophyll-a (chl-a) levels off the coast of Los Angeles. Left: Effluent is pumped through an 8.05 km long pipe and discharged at depth, minimizing environmental impact. Persistent high levels of chl-a are seen along the coast due to warm waters and shore input. Right: During the diversion, effluent is being discharged at a shallow depth, 1.61 km from the coast. Nutrients from the wastewater are able to reach the ocean’s surface, stimulating algal blooms and increasing the amount of chl-a detected. Image Credit: Los Angeles Oceans Team
This is a part of the 2015 Fall VPS. For more VPS articles, click here
Category: Mapping Water Quality
Project Team: Los Angeles Oceans
Team Location: NASA Jet Propulsion Lab ÛÒ Pasadena, California
Authors:
Rebecca Trinh
Lindsay Almaleh
Mark Barker
Mentors/Advisors:
Benjamin Holt (Oceans-Ice Group, NASA Jet Propulsion Laboratory)
Michelle Gierach (Oceans-Ice Group, NASA Jet Propulsion Laboratory)
Abstract:
The Hyperion Treatment Plant (HTP) is one of the largest wastewater treatment plants in the western United States. Treated sewage is generally released at depths of approximately 60 m through 8.05 km outfall pipes into the deep coastal waters of the Santa Monica Bay. In times of repair and maintenance, services on the main outfall pipe are temporarily suspended and require the plant to divert treated sewage to a shorter 1.6 km pipe that extends into shallow coastal zones. These shallow zones make it possible for the buoyant freshwater plumes to reach the surface, potentially contaminating the local environment. This study highlighted the use of concurrent satellite data analysis of thermal signature, surface movement, and ecosystem response to the planned wastewater diversion undertaken at HTP from Sept. 21 to Nov. 2, 2015. By combining remotely-sensed observations with GPS-equipped drogue surface drifters and in situ readings of temperature, salinity, dissolved oxygen, pH, conductivity, transmissivity, colored dissolved organic matter (CDOM), and chlorophyll-a florescence, an accurate assessment of the full impact and extent at which these effluent plumes affect the Los Angeles Basin is possible.