Oyster Castles and Asteroids

March 22nd 2023

By Jason Swope

 

The Redbuds were in full bloom as I departed from Western Maryland on a Friday evening in April.  I had an appointment the next morning in Norfolk, VA, with fellow Chesapeake Bay Landscape Professionals (CBLPs) and a group of community volunteers who were helping to build a living shoreline.   

 

Prior to this excursion, my involvement with the CBLP program had brought me up close and personal with many types of best management practices designed to mitigate the effects of stormwater runoff and protect the Chesapeake Bay. I had become familiar with practices such as rain gardens, green roofs, bioswales, and riparian buffers.  But a living shoreline was a concept that I was not familiar with, and I wanted to learn more.  I was instructed to bring work gloves and knee-high boots, so I knew this was going to be a ‘hands-on’ learning experience.

 

 

Our group would be led by Jim Cahoon with Bay Environmental, Inc, who had developed a living shoreline plan for the project site. Now approved and permitted, the project was underway.  The primary purpose of the living shoreline project was to restore and abate shoreline erosion.  The project also had a secondary purpose of creating a publicly accessible living shoreline with an oyster habitat  for educational purposes.  

 

 

Rising sea levels, extreme weather events, and urbanization have all contributed to increased shoreline erosion, the loss of habitat, and pollution.  A living shoreline helps to reduce these effects by abating wave energy while also restoring native habitats.  These habitats filter and clean the water as they develop and become part of the local ecosystem.  For our project, the establishment of a living shoreline was going to be accomplished by installing oyster castles and replenishing sand along the public access beach area. 

 

 

 

Oyster castles are interlocking blocks which are manufactured from a special blend of concrete.   They are similar in size and shape to a retaining wall block and are installed in a linear, three-dimensional layout along the shoreline.  They serve to mimic oyster reefs by providing a habitat with surface area that allows for juvenile oysters to grow on, and the blocks also  help reduce  shoreline erosion.

 

 

Over the course of the morning, a group of community volunteers along with several CBLPs carried the oyster castles to the water’s edge and assisted Jim Cahoon with the installation. The tide was rising, so time was of the essence to get the castles in place. At the same time, other volunteers were wheelbarrowing and depositing sand behind the oyster castles along the shoreline to replenish what had been lost due to erosion.   By lunch time, the pallets of oyster castles were installed, and the sand had been hand graded into place.  A volunteer effort on another day was planned to plant Spartina and other native species along the shoreline where the sand was installed.  

 

 

 

Before our group left for the day, we inspected an older shoreline project adjacent to our work area.  It was gratifying to see oysters establishing on the installed castles.  Behind the oyster castles, a marsh of Spartina was growing in the sand.  The castles held the sand in place until the plant roots could take over securing the shoreline.  As the castles became encrusted with oysters and the marsh develops, the project will blend into the landscape.   

 

Jim was kind enough to lead a question and answer session for CBLP’s and contractors, and we discussed the challenges of a living shoreline installation which include permitting, securing materials, and finding contractors and labor to install this type of best management practice.  As we wrapped up for the day, I felt the sense of gratification that comes with this type of environmental stewardship work With the rest of the weekend in front of me and my wife along for the ride, we decided to travel from Norfolk to Cape Charles, Virginia and into Maryland by way of the Chesapeake Bay Bridge Tunnel.  

 

The weather was beautiful in Cape Charles and lots of folks were out shopping, dining, and relaxing.  Later, I learned that the area near Cape Charles was the site of a major geological event over 35 million years ago when a bolide struck the earth.  While it may be a stretch to label the bolide as an asteroid, it was a large chunk of rock from outer space traveling at about 11 miles per second and it punched a hole into the earth that contributed to the formation of the Chesapeake Bay.  Known as the Chesapeake Bay impact crater, the crater was likely to have been about 25 miles in diameter and as deep as the Grand Canyon.  According to the US Geological Survey, it is believed that the impact crater created a topographic depression which helped determine the eventual location of the Chesapeake Bay.

 

 

Before heading back to western Maryland, there was enough time left in the weekend to explore some natural areas along the beach .  Growing in the dunes, I identified clumps of Seaside Goldenrod with their striking tall stems of dried flowers and seeds.  Inspiration for a bioretention plant, perhaps?

 

Over the course of the weekend, I traveled across the Chesapeake Bay watershed.  During the trip, the soils changed from mountain, to piedmont, to coastal plain, and the natural plant communities that developed with those soils and environments changed as well. As I considered the soils and plants, and the Chesapeake Bay impact crater, and the development of the watershed over geological time, I could not help but think about the direct impact humans have had on the watershed..  

 

 

We are all working with the common goal of reversing  those negative impacts..  Many don’t think about soil types and plant communities, or restoring habitat along shorelines, or storm water runoff and impervious surfaces.  But the Chesapeake Conservation Landscaping Council and its members are, and I feel fortunate to be involved with such a great community of practitioners advocating for these practices.

 

In March, I will  return to Norfolk, Virginia to attend the CBLP  Living Shorelines certificate pilot training.  The training takes place in the same location as last year’s volunteer project.  I am looking forward to seeing how the site has developed over the past year and I hope to share an update on the project in the months ahead.

 

Jason Swope is a Special Projects Associate with the CBLP program, and a career landscape management professional.  Jason works with his clients to help them transition from conventional to conservational landscaping practices.