What is beach nourishment?

Beach nourishment is the practice of adding large quantities of sand or sediments to beaches to combat erosion and increase beach width. 
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Does beach nourishment work?  Does the sand just eventually wash away?  

The short answer is yes, beach nourishment works! Although some of the new sand may erode away, that is its job! It protects the original shoreline from being washed away.
The primary goal of beach nourishment is to reduce wave energy to protect the shoreline from damage due to storm surge and overwash. Many areas of Duxbury Beach are eroding making the shoreline west of the barrier beach vulnerable.  

By widening the existing beach through nourishment, we are creating a larger buffer between Cape Cod Bay and the built-up shoreline, which ultimately provides it with a higher level of protection and stronger defense against storms.  

It’s important to note that shoreline erosion following a beach nourishment project is expected and does not mean the project was unsuccessful. The additional sand that was placed on the shoreline during beach nourishment serves as a buffer that prevents the road from bearing the brunt of wave action and storm surge. In addition, much of the sand will stay in the system - either in front of the beach, helping to reduce wave energy as it approaches the beach or further south along the beach, replenishing lost sand on another section of beach.

Sand that is placed on the beach during beach nourishment is expected to erode over time in order to achieve the primary goal of protecting the shoreline itself from eroding and washing away. It’s important to remember, loss of sediment means performance has been achieved, not a failure.

We’ve seen the benefits of beach nourishment in the past. In 1991, we repaired the beach after the “No Name” storm with a significant beach nourishment project. These repairs helped to protect the beach and built-up shoreline to the west as storms arrived in December 1992 and January 1993.  Those storms depleted the previously repaired beach and DBR rebuilt again in 1994. It’s a continuous battle.

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How was this project funded?

This project was implemented and funded by Duxbury Beach Reservation, Inc. It was made possible thanks to a MA Coastal Zone Management Coastal Resilience Grant, a federal North American Wetlands Conservation Act grant, and private donations raised during Duxbury Beach Reservation’s fundraising events. No Town of Duxbury tax dollars went towards this work.
 

Who were the project partners?

Woods Hole Group acted as the project engineer and construction oversight, Duxbury Construction was the selected contractor, and MA Coastal Zone Management provided grant funding and expertise.
 

What “work” occurs after the nourishment project is completed?  

Monitoring will continue for a period of three years after the project is completed.  This analysis will help us track the change in slope and elevation, the vegetative growth that stabilizes the dune, and the change in sediment color over time.  

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Why this location?

The dune and beach in front of Duxbury Beach Park was amongst the most narrow on Duxbury Beach. This is an area where there has been an ‘hourglass’ effect, a narrowing of the landform. Overwash at this point on our barrier beach would threaten access to the rest of the beach as well as expose the extensive salt marsh behind it to the brunt of storms. Both the barrier beach and salt marsh provide important protection from flooding and damaging waves to the mainland.
Also, sand generally moves north to south on this section of the coast. The waves are helping move sand we’ve added to the northern section of the beach, further south to nourish other parts of the beach. In the end, we increase the resilience of the beach and dune by adding nourishment to increase the sediment supply and there is nowhere on Duxbury Beach that doesn’t need sand!
 

Why are there rocks in the sand?

Rocks and cobbles have always been a part of Duxbury Beach. They help us maintain a healthy beach. They are heavier than sand and not as easy for wind and water to erode from the beach. When we plan a beach nourishment project we are required by regulatory agencies to sample and analyze existing sediment. The company that does the analysis tests for different characteristics like grain size and percentage of fine sediment. The extensive analysis of multiple samples results in an acceptable composition for nourishment material that the contractor doing the work needs to match. Since cobbles were part of the existing beach and dune, the nourishment material must also contain cobbles. While the nourished beach and dune helps restore recreational areas, the primary goal is to maintain a healthy beach.
 

Why was the sand put in the water?

By placing sand down below the waterline, incoming waves break earlier and the energy of the waves is lessened, meaning that less sand will erode from Duxbury Beach. 
 

Where does the sand come from?

We are thrilled to say the sand we used comes from Duxbury! Duxbury Beach Reservation connected with a Duxbury resident who had a project already in the works to excavate a large esker on their property. An esker is a large channel deposit left by glaciers. This local compatible sand source reduced the beach project’s carbon footprint, time, and sand cost. 
 

Why so much sand? 

Duxbury Beach Reservation worked with partners like Woods Hole Group, to design a beach and dune that would help Duxbury Beach withstand damaging storms and protect the shoreline behind it (Duxbury and parts of Kingston and Plymouth). This project  spanned some of the most narrow sections of beach and dunes, so a lot of sand was needed to build out the protective barrier beach.
 

Why doesn’t the new sand match the color of the existing beach?

The original sand on the beach has been washed, bleached by the sun, and tumbled which gives it a lighter, almost white, coloration. The newer sand was brought from an upland source. This upland sand is coated in fine-grained sediment rich in iron, making it look orange. Over time, the new sand will be washed, bleached, and tumbled too, and become much lighter. Before long it will be hard to tell apart the old and new sand!
 

Why is the new sand so soft?

This is very normal for beach nourishment and will go away as the sand settles and packs down. The phenomenon is caused by increased porosity and volume when the source sand is disturbed and moved around. The space between the grains of sand increases, resulting in more “fluid” sediment when it is first placed. 

 

What caused the large plume of sand in the water? Will the water be safe to swim in?

Sand used for beach nourishment is brought in from upland sources and hasn’t been washed like the sand already on the beach. The upland sand has fine-grained sediment coating the sand grains, which gets suspended in the near-shore when the nourishment sand gets wet –it may appear as a cloudy plume until the sediment is washed. The water is safe to swim in and the plume of sand will disappear.

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Why are there wood pieces in the sand?

The material used for this project came from a natural source area. As the sediment weathers and settles, less dense material like pieces of wood and roots, are brought to the surface. These pieces of wood play an important role in the ecosystem of the beach and provide natural habitats and shelter for a variety of wildlife. In a completely natural system, it is not uncommon for wood to erode from a coastal bank and travel to a new area along with the sand and sediment.

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Why plant beach grass?

American beachgrass and other plants help build and stabilize the dune. The grass traps windblown sand, and the roots help hold the dune together.  
 

Why is there no grass planted on the seaward side of the dune?

Duxbury Beach is lucky to be home to a wide variety of wildlife and when we plant grass or execute dune nourishment projects, we need to ensure we aren’t changing the habitats of those animals. Beach and dune nourishment projects like this one require a lengthy regulatory review process by many different agencies, including the Massachusetts Natural Heritage & Endangered Species Program (NHESP). The NHESP ensures that projects do not negatively impact nesting habitat for listed shorebirds, like the piping plover and least tern, which both nest on Duxbury Beach and within the project area. These species typically nest in open or sparsely vegetated, sand or sand/cobble areas, and so one of the project requirements was to plant only landward of the dune crest. 

      

Why an Elevated boardwalk?

​Duxbury Beach Reservation is building a beautiful elevated wooden boardwalk in front of the Pavilion/Blakeman’s Restaurant. This section of the beach and dune is extremely narrow, so we need to limit our use of it and protect it. By placing the walkway above the sand, vegetation can still grow, building and strengthening the dune. Maintaining this continuous dune results in limited pathways for wind and water to flow up and over the dune, potentially damaging the landform and infrastructure behind it. The elevated boardwalk also helps maintain wildlife habitat and creates a convenient, accessible walkway for beachgoers. We can’t wait to see all the photos taken from there!