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SAN Stormwater Management Raises the Bar on Sustainability

Thursday, October 22, 2020

SAN Stormwater Management Raises the Bar on Sustainability

The San Diego County Regional Airport Authority (Airport Authority) is making great strides in achieving our stormwater management goals through the development of an innovative stormwater capture and reuse system. The system will allow San Diego International Airport (SAN) to meet important regulatory requirements and reduce potable water consumption, making the airport more resilient to future climate and regulatory changes. There are four existing elements of the stormwater capture and reuse system, and four proposed elements. The four proposed elements are a part of the Airport Development Plan (ADP) which includes the Airside Improvements Project, the first project of the ADP that focuses on airside infrastructure such as the aircraft taxiways and apron.

Existing Elements

  1. Terminal 2 Parking Plaza (T2PP) Storage – Storage for stormwater captured from the upper deck of the T2PP with a capacity of nearly 100,000 gallons.

  2. North Side Cistern – An approximately three-million-gallon underground storage tank (cistern) on the north side of the airport that captures stormwater runoff.

  3. North Side Storage and Infiltration – Underground storage and infiltration chambers with 0.64 million gallons of capacity, and bioswales to channel stormwater infiltration on the north side of the Airport.

  4. Airline Support Building (ASB) Storage and Infiltration – Two infiltration beds with a total surface area of approximately 2.65 acres constructed as part of the ASB project.

Proposed Elements

  1. South Side Cistern – An approximately 1.5-million-gallon underground tank (cistern) on the south side of the airport constructed as part of the Airside Improvements Project that captures stormwater runoff.

  2. Airfield Storage and Infiltration – Several infiltration areas located on the airfield that will also be constructed as part of the Airside Improvements Project.

  3. Terminal 1 Parking Plaza (T1PP) Storage – Underground storage tanks or pipelines at the proposed new Terminal 1 Parking Plaza that are a part of a future ADP project.

  4. Roadway Storage and Infiltration – Underground infiltration and storage area below the proposed new Terminal 1 roadway loop ramp on the east side of the proposed new Terminal 1 parking structure as a part of a future ADP project.

In the blog post titled, Envisioning the future at SAN, we discussed working with the Institute for Sustainable Infrastructure (ISI) to apply their Envision rating system to our Airside Improvements Project as a guide for integrating sustainability into the project. Let’s take a look at some of the sustainability benefits of the proposed elements of SAN’s stormwater capture and reuse system as laid out by the Envision rating system’s framework of credits.

Envision Credit: Preserving Sites of High Ecological Value

SAN provides a protected habitat for the California Least Tern (CLT), a federally listed endangered seabird species that finds nesting opportunities along the southeastern property line of the airport during the nesting months of April through September. The Airside Improvements Project Design Team needed to work around these birds and their protected space. After a few revisions to the original plan, the South Side Cistern has been located in an area that is completely removed from the California Least Tern’s nesting area, and still allows for at least 80 percent of annual runoff volume to be captured from the minimum stormwater management area.

Envision Credit: Maximize Resilience

The Airport Authority team developed a Water Stewardship Plan with the intent of controlling discharges more effectively and eliminating unnecessary discharges. The Airport Authority’s aim is to not only meet but go beyond what is required by regulations. Exceeding regulatory requirements will enhance environmental performance and may reduce or altogether avoid future costs associated with regulatory compliance. Considering the likelihood and degree of potential regulatory changes, this strategy may ultimately save SAN money on costly retrofits should regulatory requirements change.

Envision Credit: Reduce Operational Water Consumption

Some of the stormwater collected in the South Side Cistern and at the proposed new T1PP Storage will be sent for treatment. Once treated, the water can and will be reused at the Central Utility Plant (CUP) as an alternative source of cooling water and could be used for dual plumbing at the proposed new Terminal 1 for toilet flushing. Water collected at the existing T2PP Storage already undergoes the treatment process and provides approximately 2 million gallons of stormwater per year to the CUP. In addition, water from the existing North Side Cistern will be reused by the Rental Car Center (RCC) to wash cars. Reusing stormwater reduces the use of potable water and therefore reduces the strain on local water resources.

Envision Credit: Protect Surface and Groundwater Quality

Instead of discharging into San Diego Bay, stormwater runoff is collected at SAN, along with the pollutants contained therein, and is either captured and infiltrated or conveyed to a treatment facility that allows the water to be reused. The storage and treatment of some of the collected stormwater from T2PP Storage, the South Side Cistern, and the proposed new T1PP Storage removes the associated contamination that would have occurred if the stormwater went directly into the San Diego Bay. Infiltration at the Airfield Storage and Infiltration, ASB Storage and Infiltration, and at the Roadway Storage and Infiltration areas use soil chemistry and biology to filter and treat contaminants from the airport’s stormwater as it infiltrates into the ground, rather than discharging into the bay.

Envision Credit: Reduce Construction Water Consumption

While it is currently not proposed as part of the ADP project, the Airport Authority will have the option to provide water captured by the stormwater capture and reuse system for contractors to use during construction. This would allow contractors to reuse stormwater instead of portable water for construction activities such as dust control.

As we collaborate with ISI on this critical infrastructure project, the Airport Authority is committed to sharing lessons learned and periodic updates.