Morro Bay Water Reclamation Facility Project:  Issues, Concerns, and Solutions



Addressing the Challenges


Earthquakes and Liquefaction

Liquefaction occurs during earthquakes.   Soil becomes unstable, and cannot support structures built on it.  Morro Bay is located in “earthquake country” and no matter where the plant is, it will have to be built to withstand ground shaking.  Liquefaction is a significant risk at the Hanson’s site due to sandy surface soils, but with proper construction techniques, it can be addressed.

Because of what has been learned from earthquakes all over the world, building engineers have a wealth of information on how to build structures that hold up under liquefaction conditions.  For example, the use of caissons anchored in bedrock is one approach that has been found to be very effective in many situations.


Flood Plain  

Like the site of the existing WWTP, the Hanson’s site lies in a 100 year flood plain.  Information gleaned from flooding events in this area and in other areas around the country can guide Morro Bay in building a WRF  that will withstand the expected level of flooding at the Hansons’ site.


Sewer plants in flood zones are not unusual.  In fact, the EPA provides specific, effective flood mitigation measures for sewer plants in its September, 2014 document, Flood Resilience: A Basic Guide for Water and Wastewater Utilities.  


Other communities have learned how to build resilient wastewater treatment systems and Morro Bay can benefit from their experience.  For example, the City of New York has done considerable work since Hurricane Sandy, and has developed a comprehensive wastewater system resiliency plan.  The State of Oregon, in preparation for a major earthquake along the Cascadian Rift, has prepared the Oregon Resilience Plan For Water & Wastewater Systems.

Building in a flood plain is not allowed under Morro Bay LCP policy 9.03.  There are a few exceptions, but they do not include a sewer plant.   This would mean that an LCP amendment would be required to allow building the plant at the Hanson’s site.  Collaboration with the Coastal Commission would be necessary to make this happen.


Tsunamis

Much of Morro Bay lies in a tsunami zone, but LCP policy 9.01 requires that new development be located in such a way as to minimize risk to life and property.  If Morro Bay idecides to build the new WRF at the Hansons site, it must be shown that the plant construction is done in such a way that it provides maximum protection from tsunami flooding.

The approach to addressing this concern will be similar to that used to address flood plain issues.   Collaboration with the CCC, and leveraging the knowledge and experience of other communities will help to mitigate the risk of this type of flooding.


Shoreline Erosion

The Hanson’s site is farther back from the ocean than the current WWTP and the WWTP site that CCC staff addressed in the past.  It is also, on average, a few feet higher in elevation.

With an assumed 30-year useful life for the plant, the Hanson’s site location and elevation should help to address CCC concerns. 


Archaeological Resources

The area of the Hanson’s site is known to have archaeological resources, as do most potential sites around Morro Bay.  The key is to minimize any disturbance, and to avoid it wherever possible.

A plant with a very small footprint will be important in addressing this concern and respecting the heritage of our Chumash and Salinan residents and neighbors.   A small plant footprint will minimize or avoid disturbance of archaeological resources.


Public Access and Recreation

Because the Hanson’s site is near the beach, beach access, and an RV park, there are issues regarding potential impacts to public beach access and recreation.  To address these issues, the plant must have a small footprint, a low profile, and optimal odor control.  It should be well camouflaged, and should not look like an industrial site.

There are technologies available that have these characteristics, and can meet the City’s water reclamation objectives.


Visual Resources

Concerns and mitigation for visual resource issues are essentially the same as those for public access and recreation.  A modern water reclamation facility can be designed so that there is no impact on scenic views from Highway 1.


Zoning

 A sewer plant is considered a heavy industrial use, so an LCP amendment would be required.  It should be noted that n LCP amdendment would also be required for the large lift station that the current WRF project proposes to locate on the WWTP site.  That is also a heavy industrial use.