about south river federation


oyster reefball spatted

A Chesapeake Conservation Corps Capstone Project 

Jaclyn Fisher, spent the last year volunteering 40 hours a week with the South River Federation as a Chesapeake Conservation Corps member. As part of this Chesapeake Bay Trust program, each corps member needs to complete a capstone project. Because of Jaclyn’s experience and interest in oyster restoration, she chose to help us figure out the logistics behind incorporating oyster reef balls into a living shoreline that is being installed at Turnbull Estates in Glebe Bay. It might sound simple to add some oysters to a shoreline project, but the logistics are many and varied. The Federation very much appreciates the amount of time and energy Jaclyn invested in helping us figure out the different potential approaches.


Project Abstract/Background

  1. Introduction to Living Shorelines and Oysters Reef Balls
  2. Reef Ball Information
  3. Project Logistics
  4. Project Timeline Restrictions

A. Living Shoreline Incorporating Reef Balls

Erosion is a natural process along shorelines due to wind and wave action, however human activities, like increased impervious surface cover and high speed boating, have increased rates of erosion aoyster reef balls living shorelinelong many shorelines. Living shorelines are a natural approach to reduce erosion using native vegetation, whose roots help to stabilize the shoreline. The benefits of living shorelines include not only stabilization, but the protection of surrounding riparian and intertidal areas, improvement of water quality due to filtration of run-off, and habitat creation1. Adding a “living” breakwater can further help with stabilization by creating a wave break, therefore reducing wave action and further slowing erosion.

Man-made structures such as bulkheads, rockwalls, and armored shorelines are known for their ability to reduce erosion, however these man-made structures tend to reflect wave energy, not absorb it, which can end up destroying the shallow water habitats they intend to preserve2. Living breakwaters, which incorporate oysters, are able to dissipate wave energy making them a better alternative. In a living breakwater, bags of oyster shells or reef balls are used as the main structure, either with or without the added benefit of habitat creation through the addition of oyster spat3.

South River Federation is working on a living shoreline project that will incorporate reef balls at Turnbull Estates near the Glebe Bay Oyster Sanctuary. The current site is eroding sediment into the oyster sanctuary, making it a prime target for this type of living shoreline project. The concept for the project incorporates the placement of reef balls offshore with shoreline plantings of native aquatic vegetation to create a tidal marsh. The reef balls will serve to protect the living shoreline from wave action, together having the benefit of filtering pollutants from the water and reducing erosion at Turnbull Estates.

While we believe that this is the first living shoreline in Maryland that is incorporating reef balls, it is not the first project in Maryland to use reef balls as “living breakwaters.” One such project includes Calvert Cliffs, where reef balls are being used offshore in hopes of slowing erosion4.

B. Reef ball Information

A reef ball is a designed artificial reef made of marine friendly concrete and is designed to mimic natural reef systems. They come in multiple sizes, which include5:

  • Reef Ball: 6’x4’, 3500-4500 pounds
  • Pallet Ball: 4’x3’, 1500-2200 pounds
  • Bay Ball: 3’x2’, 375-750 pounds
  • Lo Pro Ball: 2’x1.5’, 80-130 pounds


C. Turnbull Living Shoreline Project Logistics

The primary project goal of the Turnbull Estates Living Shoreline is to install a functional living shoreline. Within this project, the Federation hopes to use reef balls as a “living breakwater” to dissipate wave energy coming towards the shoreline, thereby reducing the erosive wave action that is eating away at the shoreline. The utilization of reef balls in the place of conventional “rip-rap” or rock provides a way to reduce cost by reducing the amount of rock used and purchased, as well as increasing habitat for a variety of species.


The Federation also has sub-goals for the project, which are not to be sacrificed for the integrity of the shoreline, but should be taken into consideration whenever possible. These goals include the use of reef balls and oyster spat, strengthening and building partnerships with other organizations, and outreach and engagement with the community.

Implementation Steps:

Parts of the project have been broken into smaller “implementation steps,” in which there are multiple options for execution. These steps include: options for the reef ball structure, creation of the reef ball structure, placement of spat, deployment of the reef balls, and planting of the living shoreline. A summary of options for these “implementation steps” can be seen after Part D, in Table 2.

Options for Reef Ball Structure

Reef balls come in a variety of sizes, as outlined above. While larger reef balls may have a greater capacity to reduce wave action, the reef balls will be placed in a shallow offshore area. Larger reef balls increase the chance that oysters will be exposed to the air for long periods of time, which increases the chances of oyster mortality. While this is not an oyster restoration, it is best to take steps to increase the chances of survival for oyster spat. The smaller reef balls (lo pro and bay ball sizes) are also lighter and therefore easier to maneuver. Even a bay ball can weigh upwards of 400 pounds, while a pallet ball can weigh over 1000 pounds, both of which would require heavy machinery to move. Potential partner from the Coastal Conservation Association (CCA), David Sikorski, has reported that CCA currently has approximately 100 reef balls stockpiled and ready for use at the Lehigh Cement Facility in Carroll County, MD. For these reasons, it is recommended to use lo pro reef balls.


temperature table


Creation of Reef Structure

The creation of the reef structure is a great opportunity for partnership building and outreach into the community. Coastal Conservation Association (CCA), Chesapeake Bay Foundation (CBF) and Cat South High School all have the capacity to build reef balls. Partnering with CCA meets our goals of both community outreach and partnership building, as the Federation has never worked on a project with them before. They are experienced with building reef balls and are able to get Lehigh Cement to donate cement to build reef balls, thereby reducing costs, by working with schools in the community. Furthermore, as mentioned above, CCA already has a supply of reef balls that the Federation would be able to use. For these reasons, working with Coastal Conservation Association to create the reef ball structure is recommended. Some considerations when working with any partner include: how the reef ball will be moved after construction, as well as where they will be stored. CCA owns a 16-foot landscaping trailer that will be taken to any reef ball builds (schools or otherwise) and can move 20 or so reef balls per load.  The trailer is rated for 8000 lbs., if towed by the proper truck. In the past they have reimburse for mileage driven by volunteers to tow their trailer and move reef balls at the federal rate (53.5 cents/mile, currently). Depending on the number of reef balls required by the design, one way to limit costs and increase volunteer involvement is to use CCA’s trailer to move the reef balls to Turnbull. However, in the past, they have also hired trucks to move large amounts of reef balls at a cost of $550 per load, which carried approximately 88 reef balls. This would be a much faster way of transporting the reef balls to the Turnbull but also potentially much costlier.

spatting oyster reef balls




Placement of Spat

While not necessary to create a living breakwater, spatting the reef balls would increase the habitat value of the project, as well as increase the public’s interest in the project. Chesapeake Bay Foundation (CBF) is experienced in spatting reef balls and has the equipment necessary to do so. Their facility is not far from the project location, located at 4800 Atwell Road Shady Side, MD, approximately 14 miles away from Turnbull Estates. This keeps potential moving costs lower, and CBF also has the capability to potentially deploy the reef balls using the Patricia Campbell. The only other known location that has the capacity to spat reef balls is the Horn Point Oyster Hatchery, located at 2020 Horns Point Road, Cambridge, MD, approximately 69 miles from Turnbull Estates. This is significantly further away from the both the site and where the reef balls will be constructed (around the Annapolis area) and therefore the cost to move reefballs to Horn Point would be much more expensive. Therefore, the recommended partner for spatting the reef balls is the Chesapeake Bay Foundation, if the Federation decides to do so.



installing oyster reef balls



Deployment of Reef Structure

The Federation has two options when it comes to the deployment of the reef balls. Either the contractors, Resource Restoration Group (RRG), can deploy the reef balls by land, or the Chesapeake Bay Foundation can deploy the reef balls via the water with the Patricia Campbell. Each option has its obstacles. While RRG is confident in their ability to deploy the reef balls, they have never worked with reef balls or deployed these structures in this way. Made of concrete, they are heavy and can crack if not handled properly. Using this method, the contractors deploy each reef ball one by one, which could take an extensive amount of time. I am also unsure of the precision on this method. With the Patricia Campbell, the Chesapeake Bay Foundation is able to deploy four reef balls at a time, deploying 200 lo pro reef balls or 100 bay balls in one day making the process much faster. It does take one day to load the reef balls on to the boat, however. Deploying reef balls via the water on the Patricia Campbell, while done many times before, also has its drawbacks. The Patricia Campbell requires 4.5 feet of water at low mean tide in order to deploy reef balls and the water offshore of the Turnbull peninsula is shallow, which could restrict the areas the Patricia Campbell could reach. The deployment arm on the Patricia Campbell has a span of 20 feet, which does give the Federation some wiggle room. CBF has lots of experience handling reef balls and deploying them offshore. Therefore, I recommend continuing the partnership with CBF and utilizing the Patricia Campbell to deploy the reef balls, upon completion of a bathymetry survey or land survey that confirms the depth of the offshore waters will be able to support the boat.


Turkey Point compressed2



Planting of Living Shoreline

As with any planting the Federation has multiple options. The Federation can use volunteers, contractors, or pre-release inmates to plant the living shoreline. Both contractors and pre-release inmates would most likely take less time than volunteers, however, they also increase the cost of the project and don’t contribute to the Federation’s goal of community outreach. Volunteers, while they might take more time, both in terms of planting and staff time, cost less and meet the Federation’s goal of community outreach. If there is a large amount of shoreline to be planted, the best option may be to use a mixture of hired help and volunteers. However, because of the interest in this project, I recommend using volunteers for the planting. Generally, living shorelines are popular, as well as less strenuous, to plant. I doubt it will be difficult to find volunteers for this planting, so not only will this help the Federation reach its goal of engaging the community, but it can also be a cost-saving measure.



D. Project Timeline Restrictions:

A few important restrictions should be taken into consideration when planning the timeline for the Turnbull Estates Living Shoreline project. These restrictions encompass both the construction of the materials needed for the living shoreline, as well as the availability of potential partners. In the construction of the physical reef balls, it is important to consider that concrete will not set correctly below freezing temperatures (32oF). Freezing temperatures increase the probability that water will freeze, forming ice within the concrete that will expand and crack the concrete6. Furthermore, the colder the weather, the longer it takes concrete to set (see Table 1)7. Hot temperatures can also cause problems while curing concrete. Concrete sets much faster when the air temperature is above 90oF and when concrete sets it shrinks. In the heat, the top layer will dry much more quickly than the bottom layers, shrinking while the layers underneath are not. Spatting of the reef balls is also a temperature dependant process that needs to be taken into consideration. Oysters spawn at water temperatures between 74 and 86oF (20 to 30oC) and at salinities above 10ppt8CBF is able to spat reef balls at any date from April through August. CBF’s spat setting policy also includes that freshly made reef balls need to have set at least 30 days before being put in the setting tank, meaning if a reef ball was completed in mid-April, it would need to sit until mid-May until it was ready to be placed in the setting tank.


Image 1: Restrictions within the Project Timeline.

If the Federation plans on partnering with the Coastal Conservation Association (CCA), which uses various school partners to build reef balls, then another restriction to consider is the timing of the school year. By partnering with CCA, the Federation stands not only to save money on reef balls through donated cement, but meeting both its goals of community outreach and partnership building. Anne Arundel County Schools open right after Labor Day and close mid-June9. There is also about a two month window in which the Federation can engage students in the spatting of the reef balls, at the end of their school year. CBF can begin spatting reef balls in April and the last day of school for Maryland students is June 15th, with many schools conducting testing at the end of the year. The above restrictions are mapped out in Image 1, above.


Options for Structure Creation of Reef Structure Placement of Spat Deployment of Reef Structure Planting of Living Shoreline

Reef Balls ~ 2 feet

(Lo Pro or Bay Ball)

PROS: lighter and easier to maneuver, can fit more when   transporting, less likely to expose oysters on low tides

CONS: will have to use rock to reinforce the breakwater


PROS: already have reef balls we can use, are able to   work with schools (outreach), potential to get cement donated by Lehigh, opportunity   for parternship-buiding – new partner

CONS: how to move the reef balls after they are built?   Trucking them?

  • CCA owns a   trailer and uses it to move reef balls after construction at schools.



CONS: CCA doesn’t have the capacity to spat reef balls

RRG/Contractors deploy by land


CONS: Will have to move/truck the reef balls to the site.   How long will this method take, done one-by-one? What is the precision of   this method?

SRF – Volunteers

PROS:   Great community outreach   opportunity. Lots of public interest in project. Less costly than hiring a   crew.

CONS: Would have to arrange multiple planting days, cost   of staff time

Reef Balls (larger   sizes)

PROS:   Don’t need re-enforcing

CONS: heavy and difficult to maneuver, more likely to be   exposed during low tide (increased oyster mortality)


PROS:   experienced in creation of reef   balls, have some reef balls already created, would be easy to have them   complete the whole process

CONS: little room for community outreach


PROS: experienced in spatting of reef balls, would be   easy to have them complete the whole process

CONS: little room for community outreach

CBF (Patricia Campbell)

PROS:   experienced in placement of reef   balls, have the PC, opportunity for partnership-building

CONS: The PC needs 4.5 feet of water – unsure of how   shallow the area is.

SRF – Contractors

PROS: Hard workers, could probably get the planting done   in less time than volunteers

CONS: Lacks community outreach component, cost of labor

Reef Castles


CONS: no sign that anyone has molds for them

Cat South (HS)

PROS: Great opportunity for outreach into the community,

CONS: what would we need to provide? difficult and   specific process that we don’t want to mess up, Large project for one school

Horn Point

PROS: experienced in spatting of reef balls

CONS: transportation of ~200 400lb. reef balls to Horn Point   from where they were built. Cost?

CCA or Trucking Company

Depending on the number of reefballs   required, either make many trips with the trailer or hire a trucking company.   Cost of gas vs. cost to hire.

RF – Inmates

PROS: Hard workers, could probably get the planting done   in less time than volunteers

CONS:   Lacks community outreach component,   cost of labor

Table 2: Summary of implementation steps. Steps highlighted in gray are the recommended options.


1 “Living Shorelines.” NOAA Habitat Conservation and Restoration Center, Web. <http://www.habitat.noaa.gov/restoration/techniques/livingshorelines.html>.

2 “Living Shorelines for the Chesapeake Bay Watershed.” Chesapeake Bay Foundation, Sept. 2007. Web. <http://www.cbf.org/Document.Doc?id=60>.

3 “Living Shorelines: Design Options – Oyster Reef.” Virginia Institute of Marine Science, Web. < http://ccrm.vims.edu/livingshorelines/design_options/oyster_reef.html>.

4 “Chesapeake Ranch Estate's Maryland Eastern Shore Breakwater Project Photos.” Reef Ball Foundation, 1993. Web. < http://www.reef ball.org/album/maryland/breakwaterproject/>.

5 “Technical Specifications for Reef balls.” The Reef Ball Foundation, October 25, 2007. Web. <http://www.reef ball.org/technicalspecs.htm>.

6 “Placing Concrete in Hot or Cold Weather.” Sakrete, Web. <http://www.sakrete.com/blog/placing-concrete-in-hot-or-cold-weather>.

7 “Use of Admixture and Its Effects on Setting Time.” Penn State University, Web. <http://www.engr.psu.edu/ce/courses/ce584/concrete/library/materials/Admixture/Link-settime.htm>.

8 “Oyster Life Cycle.” University of Maryland Center for Environmental Science Horn Point Oyster Hatchery, Web. <http://hatchery.hpl.umces.edu/oysters/oysters-life-cycle/>.

9 “2017-2018 School Calendar.” Anne Arundel County Public Schools, Web. <https://www.aacps.org/site/handlers/filedownload.ashx?moduleinstanceid=6890&dataid=15729&FileName=20172018.pdf>.