Backbarrier Erosion Monitoring at Cumberland Island National Seashore: 2018 Data Summary
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National Park Service U.S. Department of the Interior Natural Resource Stewardship and Science Back Barrier Erosion Monitoring at Cumberland Island National Seashore 2018 Data Summary Natural Resource Data Series NPS/SECN/NRDS—2018/1179 ON THE COVER Island margin looking south at Raccoon Key on Cumberland Island National Seashore. Photo by J.M. McDonald, SECN. Back Barrier Erosion Monitoring at Cumberland Island National Seashore 2018 Data Summary Natural Resource Data Series NPS/SECN/NRDS—2018/1179 Jacob M. McDonald1,2 and M. Brian Gregory1 1National Park Service Southeast Coast Inventory and Monitoring Network 135 Phoenix Road Athens, GA 30605 2University of Georgia Warnell School of Forestry and Natural Resources 135 Phoenix Road, Room 110 Athens, GA 30605 August 2018 U. S. Department of the Interior National Park Service Natural Resource Stewardship and Science Fort Collins, Colorado The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, Colorado, publishes a range of reports that address natural resource topics. These reports are of interest and applicability to a broad audience in the National Park Service and others in natural resource management, including scientists, conservation and environmental constituencies, and the public. The Natural Resource Data Series is intended for the timely release of basic data sets and data summaries. Care has been taken to assure accuracy of raw data values, but a thorough analysis and interpretation of the data has not been completed. Consequently, the initial analyses of data in this report are provisional and subject to change. All manuscripts in the series receive the appropriate level of peer review to ensure that the information is scientifically rc edible, technically accurate, appropriately written for the intended audience, and designed and published in a professional manner. This report received informal peer review by subject-matter experts who were not directly involved in the collection, analysis, or reporting of the data. Data in this report were collected and analyzed using methods based on established, peer-reviewed protocols and were analyzed and interpreted within the guidelines of the protocols. Views, statements, findings, conclusions, recommendations, and data in this report do not necessarily reflect views and policies of the National Park Service, U.S. Department of the Interior. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the U.S. Government. This report is available from the Southeast Coast Network website and the Natural Resource Publications Management website. Data summarized in this report can be found at the Aquarius Web Portal. If you have difficulty accessing information in this publication, particularly if using assistive technology, please email [email protected]. Please cite this publication as: McDonald, J. M., and M. Brian Gregory. 2018. Back barrier erosion monitoring at Cumberland Island National Seashore: 2018 data summary. Natural Resource Data Series NPS/SECN/NRDS—2018/1179. National Park Service, Fort Collins, Colorado. NPS 640/147821 August, 2018 ii Contents Page Figures . iv Tables . v Summary and Key Findings . ��������������������������������������������������������������������������������������������������������������������������������� 1 Cumberland Wharf . ������������������������������������������������������������������������������������������������������������������������������������ 1 Brickhill Bluff . 1 Plum Orchard . ��������������������������������������������������������������������������������������������������������������������������������������������� 2 Dungeness Wharf . 2 Raccoon Key . 2 Introduction . 4 Study Area . 4 Cumberland Wharf . ������������������������������������������������������������������������������������������������������������������������������������ 4 Brickhill Bluff . 5 Plum Orchard . ��������������������������������������������������������������������������������������������������������������������������������������������� 5 Dungeness Wharf . 5 Raccoon Key . 5 Methods . 6 Results . 7 Cumberland Wharf . 8 Brickhill Bluff . 9 Plum Orchard . ������������������������������������������������������������������������������������������������������������������������������������������� 10 Dungeness Wharf . 11 Raccoon Key . 12 Literature Cited . ������������������������������������������������������������������������������������������������������������������������������������������������� 13 Appendix A. Cumberland Island Erosion Monitoring Site Metadata . ������������������������������������������������������������������� 14 Cumberland Wharf . ���������������������������������������������������������������������������������������������������������������������������������� 15 Brickhill Bluff . 16 Plum Orchard . ������������������������������������������������������������������������������������������������������������������������������������������� 17 Dungeness Wharf . 18 Raccoon Key . 19 iii Figures Page Figure 1. Overview map of Cumberland Island National Seashore (CUIS) with the locations of the island margin monitoring sites. 3 Figure 2. Example setup for an integrated survey using the resection method to setup the total station. Inset shows the difference between poor and good total station/hub orientations. ��������� 6 Figure 3. Island margin retreat at Cumberland Wharf. 8 Figure 4. Island margin retreat at Brickhill Bluff. 9 Figure 5. Island margin retreat at Plum Orchard. 10 Figure 6. Island margin retreat at Dungeness Wharf. 11 Figure 7. Island margin retreat at Raccoon Key. ���������������������������������������������������������������������������������������� 12 Figure A1. Map of the area near Cumberland Wharf. ���������������������������������������������������������������������������������� 15 Figure A2. Map of the area near Brickhill Bluff. 16 Figure A3. Map of the area near Plum Orchard. ������������������������������������������������������������������������������������������� 17 Figure A4. Map of the area near Dungeness Wharf. 18 Figure A5. Map of the area near Raccoon Key. 19 iv Tables Page Table 1. Summary of the change in shoreline position (horizontal) at Cumberland Island National Seashore, 1983–2002 . .. 7 Table A1. Benchmark coordinates. All coordinates are in UTM 17N (horizontal datum—NAD83 and vertical datum—NAVD88). 14 Table A2. Coordinates for the beginning and ending points at each survey site. All coordinates are in UTM 17N (horizontal datum—NAD83). 14 v Summary and Key Findings In 1999, the National Park Service’s (NPS) Inventory potential influence Hurricane Irma had on the island. A brief and Monitoring (I&M) Program (now I&M Division) summary of the 2017 and 2018 surveys is provided below. substantially expanded a pilot long-term ecological The main report provides some background on each of the monitoring program known as “Vital Signs Monitoring” to study sites, a general overview of the methods used to collect cover more than 270 parks. The program was designed to and process the data, and a more in-depth look at the results provide the minimum infrastructure required to identify of the surveys. and monitor the conditions of the highest priority resources within the National Park System (Fancy et al. 2009). The Cumberland Wharf Southeast Coast Network (SECN) was one of thirty-two • The Cumberland Wharf survey was 153 meters (502 feet networks formed to implement the I&M Division’s program [ft]) in length along the top of the bluff. and is tailored to the specific needs of the parks within the network. • From 2013 to 2017, 84% of the surveyed area showed some change in position. The overarching purpose of SECN natural resource monitoring is to (1) collect and produce scientifically sound • From 2017 to 2018, 100% of the surveyed area showed data that describes the current status of—and long-term some change in position. trends in—the composition, structure, and function of park • From 2013 to 2017, maximum retreat was 5.74 meters ecosystems, and (2) to determine how current management (18.8 ft) with an average of 1.82 meters (6.0 ft). practices are sustaining these systems. The Southeast Coast Network achieves the above purposes by implementing • From 2017 to 2018, maximum retreat was 2.37 meters long-term monitoring protocols and providing additional (7.8 ft) with an average of 0.98 meters (3.2 ft). technical assistance when necessary. This report provides the results of a technical assistance project implemented at • From 2013 to 2017, maximum rate was 1.32 meters per Cumberland Island National Seashore (CUIS) to monitor year (4.3 ft per year) with an average of 0.43 meters per island margin retreat on the back barrier (west) side of the year (1.4 ft per year). island. Brickhill Bluff On 19–20 June 2017, the Southeast Coast Network and • The Brickhill Bluff survey was 233 meters (764.4 ft) in the United States Geological Survey (USGS) conducted length along the top of the island margin. an island margin survey of five sites on the back barrier side of Cumberland Island National Seashore. These five • From 2013 to 2017, 88% of the surveyed area showed sites, Cumberland Wharf (CW), Brickhill Bluff (BB), Plum some change in position. Orchard (PO), Dungeness Wharf (DW), and Raccoon Key • From 2017 to 2018, 97% of the surveyed margin showed (RK), had previously been monitored by the USGS from some change in position. December 2011 to February 2013 to determine the average rate of island