Reactionary fence installation for post-Superstorm Sandy dune recovery

Abstract

Dunes are invaluable to coastal areas as dynamic buffers to erosion during high tides and storms, but do not accrue naturally in developed areas without assistance. Wood paling fencing is commonly used to cultivate dune development and thereby increase the protection afforded to coastal areas. In 2012, Superstorm Sandy devastated the mid-Atlantic, especially New Jersey where many areas are still recovering. At Island Beach State Park, NJ parts of the primary dune system were destroyed and efforts were made to rebuild these areas as an emergency response. These efforts consisted of the installation of fencing in straight and zigzag patterns to catch-windblown sand and rebuild dunes. We collected field measurements of the short-term vertical sand accretion of recovering fenced localities and non-destroyed established dunes receiving no management intervention. We also collected 1.5 m cores to examine particle size after sieving in a Ro-Tap cascade shaker. There was high stochasticity among weekly changes in dune height and fence configuration affected growth rates. Zigzag fenced areas increased in height over time whereas straight fenced dunes did not. The sand composition of the dunes varied with height such that coarse sand decreased with height whereas finer sediments increased. At the initial stage of recovery fencing configuration seems to be an important factor in determining dune growth and assessing particle size can give insight into the means of sand transport. These results have implications for coastal management and restoration aimed at accruing the most sand in least time for immediate post-storm recovery efforts.

The effect of sand fencing on the morphology of natural dune systems

“…On developed barrier islands, natural dune-building processes are often modified by management activities designed to improve beach conditions and/or provide protection from storms. These management activities can include beach nourishment (e.g., Smith et al, 2009), beach grass planting (e.g., Hacker et al, 2019), sand fencing (e.g., Nordstrom and Mccluskey, 1985;Nordstrom et al, 2000;Miller et al, 2001;Anthony et al, 2007;Jackson and Nordstrom, 2011;Charbonneau and Wnek, 2016;Jackson and Nordstrom, 2018), and removal of beach wrack by raking (e.g., Nordstrom et al, 2012). Such management efforts are typically designed to increase beach width and build tall frontal dunes that reduce the probability of overwash (i.e., wave overtopping of the foredune), though sometimes there is a preference for narrower beaches and shorter dunes to preserve ocean views (Nordstrom et al, 2000).…”

“…Sand fences are often emplaced seaward of the existing (or previously existing) natural foredune, typically in response to an erosional event (Charbonneau and Wnek, 2016), to initiate the formation of a new foredune seaward of the natural foredune (Fig. 1), making them effective for post-storm dune recovery (Charbonneau and Wnek, 2016) and erosion control (Anthony et al, 2007).…”

“…Sand fences are often emplaced seaward of the existing (or previously existing) natural foredune, typically in response to an erosional event (Charbonneau and Wnek, 2016), to initiate the formation of a new foredune seaward of the natural foredune (Fig. 1), making them effective for post-storm dune recovery (Charbonneau and Wnek, 2016) and erosion control (Anthony et al, 2007). Previous studies on the use of sand fences have focused on the construction and aerodynamic properties of sand fences (e.g., Cornelis and Gabriels, 2005;Li and Sherman, 2015;Gillies et al, 2017;Lima et al, 2017) and their monthly to annual impacts on foredune morphology (e.g., Mendelssohn et al, 1991;Miller et al, 2001;Anthony et al, 2007;Charbonneau and Wnek, 2016;Jackson and Nordstrom, 2018).…”

“…1), making them effective for post-storm dune recovery (Charbonneau and Wnek, 2016) and erosion control (Anthony et al, 2007). Previous studies on the use of sand fences have focused on the construction and aerodynamic properties of sand fences (e.g., Cornelis and Gabriels, 2005;Li and Sherman, 2015;Gillies et al, 2017;Lima et al, 2017) and their monthly to annual impacts on foredune morphology (e.g., Mendelssohn et al, 1991;Miller et al, 2001;Anthony et al, 2007;Charbonneau and Wnek, 2016;Jackson and Nordstrom, 2018). However, it is unclear how the emplacement of sand fences seaward of a pre-existing natural foredune influences the morphology of the natural foredune itself after sand fence emplacement.…”