«Presented by the Carolina Environmental Program Morehead City Field Site Students: Joseph Hester, Alison Kitto, Elizabeth Newland, Erika Poarch, ...»
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Appendix 1: Research Needs In addition to the research conducted in this study, we have discovered several research needs that are essential in order to better understand the impacts of bulkheads on the surrounding salt marsh habitat. Listed below are future research suggestions.
• Bulkheads, typically installed in order to prevent land erosion, may alter water flow and sediment suspension. Bulkheads increase rates of sedimentation and erosion by eliminating the natural shoreline buffer that reduces water flow and decreases sediment suspension. Herein lies a contradiction to the role of a bulkhead, therefore further research is needed in order to determine if bulkheads decrease net shoreline erosion and water turbidity.
• Increased sediment suspension, caused by alterations in current flow by the presence of a bulkhead, is thought to have a negative effect on marsh productivity. Impacts of increased turbidity are not exclusively limited to marshes, as seagrass beds and other submerged aquatic vegetation may also be negatively affected. Additional research is needed in order to further quantify these proposed effects.
• Bulkheads act as a roadblock for groundwater transportation of organic and inorganic particles. This has the potential to make the land behind the bulkhead contaminated with pathogens and pollutants, as well as the potential to pollute well water. There has been little done to examine the effect on the landward side of the bulkhead, therefore an assessment of the impact of bulkheads on the transport of nutrients, pathogens and other pollutants from groundwater into estuarine waters needs to be conducted in order to gain a better understanding of the bulkheads’ landward environmental footprint.
• Research assessing how bulkheads alter waves and long shore currents is lacking. Models have predicted the effects of SHS on waves and currents, but have reached varying conclusions. Field experiments have yet to quantify these physical processes to confirm modeling predictions. Until concrete conclusions are reached, the affects of SHS on wave attenuation remain speculative.
• Another research need that should be addressed is the biological impacts of non-native species inhabiting the bulkhead. The placement of a hard substrate, such as a SHS, welcomes barnacles and other non-native species to this habitat. This could potentially have a negative impact on native species, therefore more experiments need to be conducted testing these non-native species introductions.
• Further research needs to be conducted regarding the motivation behind a landowner’s decision to install a SHS. This decision could stem from socioeconomic influences or out of a desire to protect one’s property. Observational methods, such as door-to-door or mail in surveys, could prove to be a vital research tool. The type of SHS chosen should also be studied, in order to determine if structural preferences vary geographically or among different income groups.
• The citing of a bulkhead, its location relative to the shoreline profile and to adjacent marsh, may impact the range, magnitude, and duration of habitat disruption. For instance, Spalding and Jackson (2001) found that bulkheads constructed lower on the profile had a negative impact on meiofaunal abundance. To determine the proper citing of a bulkhead, similar field studies are needed to assess the specific impacts of a bulkhead’s location on additional flora, fauna, sediment, and physical processes.
• A rise in sea level is currently ongoing and expected to continue in response to global climate change. As a result, salt marshes will be submerged and transformed, forcing a shift in marsh habitat. The potential impact bulkheads can have on adjacent marshes due to expected sea level rise needs to be determined. Bulkheads physically alter the biological and chemical processes of the marsh; therefore, the impact of bulkheads on retreating marshes must be quantified in order to improve management strategies.
• In order to formulate effective policies that can efficiently manage shoreline erosion in our estuarine waters, it is critical to determine the extent to which the North Carolina coast is actually armored and how much of the coast is still in its natural state. Only when local county officials can accurately assess large scale erosional stresses can they set out to develop comprehensive rules and procedures to address system-wide problems.
As long as erosion is handled on a case-by-case basis, it is impossible for regional decision makers to work together toward any kind of proactive solution.