link to Maritime Forest Study introduction
link to Assateague Island study
link to Fire Island study
Sandy Hook Study Area
Sandy Hook is a 10-kilometer (km)-long spit that extends from the bridge across the Navesink River at the southern end to New York Harbor at the northern tip (Figure 1). Sandy Hook has experienced long-term erosion at the southern, narrow end of the spit and deposition at the northern end. As is typical of barrier-island environments, Sandy Hook experiences overwash events during which areas that are normally above tide level are flooded (Carleton, et. al.). The 10 highest water levels at Sandy Hook since 1932 range from 1.091 to 2.709 m above mean higher high water (MHHW), including record high water for the period of record during Hurricane Sandy in 2012 (National Oceanic and Atmospheric Administration, 2018). Of the 10 highest water levels in the 85-year period of record, 4 are associated with tropical storms, 4 with late fall/early winter nor’easters, and 2 with spring nor’easters.
link to Assateague Island study
link to Fire Island study
Sandy Hook Study Area
Sandy Hook is a 10-kilometer (km)-long spit that extends from the bridge across the Navesink River at the southern end to New York Harbor at the northern tip (Figure 1). Sandy Hook has experienced long-term erosion at the southern, narrow end of the spit and deposition at the northern end. As is typical of barrier-island environments, Sandy Hook experiences overwash events during which areas that are normally above tide level are flooded (Carleton, et. al.). The 10 highest water levels at Sandy Hook since 1932 range from 1.091 to 2.709 m above mean higher high water (MHHW), including record high water for the period of record during Hurricane Sandy in 2012 (National Oceanic and Atmospheric Administration, 2018). Of the 10 highest water levels in the 85-year period of record, 4 are associated with tropical storms, 4 with late fall/early winter nor’easters, and 2 with spring nor’easters.
The Bayside Holly Forest on Sandy Hook, one of only two known old-growth American holly (Ilex opaca) maritime forests, is particularly vulnerable to global climate change because of the proximity of the water table to land surface in low-lying areas and the potential for saltwater intrusion and inundation. During Hurricane Sandy the peak storm surge was 2.44 m above mean higher high water (MHHW), almost a meter higher than the previous high of 1.48 m (1960 and 1992). The Bayshore Holly Maritime Forest on Sandy Hook suffered mortality in low-lying areas that were inundated during Hurricane Sandy. Stalter and Heuser (2015) conclude the mortality occurred in areas where standing saltwater remained for about two weeks after the storm. However, measurements of the timing and extent of the inundation were unavailable to verify this conclusion.
Although flooding of roots with saltwater is hypothesized to be the cause of mortality, data on short-term and long-term water-levels and salinity in the affected areas are not available. Water-level and salinity data collected in this study in low-lying areas of the Bayshore Holly Forest may provide some of the information needed to estimate if saline water was the cause of mortality and attempt to reconstruct the duration and concentration of standing water.
Well locations
The study area was located approximately 3.5 miles south of the northern tip of Sandy Hook and to the west of the main road (Hartshorned Drive) (Figure 2). Wells near the shoreline were installed adjacent to a tidal marsh (Figure 3) and extended inland along a 55 ft. transect (Figures 4a and b). Three shallow wells (GWW31, GWW 32 AND GWW33) were hand augered and screened just below the water table (4-5 ft below Land Surface Datum [LSD]). A deep well (GWW34) was installed next to GWW33 and screened approximately 20 ft below LSD. The inland well (GWW30), located in the middle of a high mortality zone, was hand augered and screened just below the water table (4-5 ft below Land Surface Datum [LSD]).
Sandy Hook Storm Events
Storm events were illustrated by overlaying water level and specific conductance readings for each of the wells on a hydrograph of tidal elevations. Forcing conditions were represented on a graph plot of windspeeds and daily precipitation. Tidal data was retrieved from the Tides/water Levels page of the National Oceanographic and Atmospheric Administration (NOAA) Sandy Hook, NJ Station (ID: 8531680) website (https://tidesandcurrents.noaa.gov/stationhome.html?id=8531680). Wind speed data was retrieved from the NOAA Meteorologic Observations page NOAA for the Sandy Hook, NJ Station (ID: 8531680) website (https://tidesandcurrents.noaa.gov/met.html?id=8531680) Precipitation data was retrieved from the New Jersey Department of Environmental Protection Division of Water Monitoring and Standards (DWM&S) Rainfall Data Acquisition website (NJDEP New Jersey Department of Environmental Protection - Rainfall (rutgers.edu); Site: Highlands RABCH022; 2.5 X 2.5-mile area).
Five storms impacting the Sandy Hook study area were selected for analysis and are summarized in Table 1. Storms selected for analysis had either rainfall greater than 1 in. and/or wind speeds greater than 20 mph. Winter storms with significant accumulation and wind speeds greater than 20 mph were not included in the set. The duration of events was defined as the extent of either the water level or specific conductance response. The actual forcing condition was usually of shorter duration occurring at the start of the event.
In general, over the course of the study, GWW 31 was inundated by high tide most weeks and GWW 32 was inundated frequently by storm surges or very high tides. GWW 33/34, which were the furthest upslope on the transect, were inundated only a few times during large storm events with severe flooding. Inundation of the inland well (GWW30) was not observed during the study, but water levels did exhibit a slight response to sustained sea level oscillations during highest of high tide events and a slight to significant response during storm events.
| Event Number | Event Type | EventStart Date | Event End Date | Event Precipitation as rain (in.)1 | Maximum Daily precipitation as rain (in.)1 | Maximum Daily Precipitation Date1 | Maximum Sustained Wind speed (knots)2 | Maximum Sustained Wind Speed date2 | Maximum Tide Elevation (NAVD88, ft)1 | Maximum Tide Date |
| 1 | Heavy Rain/ High Wind/High Spring Tide | 10/26/17 | 11/13/17 | 3.72 | 2.55 | 10/30/17 | 27.8 | 10/30/17 | 1.51 | 11/5/17 |
| 2 | Heavy Rain/High Wind | 4/12/18 | 4/30/18 | 2.58 | 1.46 | 4/17/18 | 24.41 | 4/19/18 | 2.06 | 4/16/18 |
| 3 | Heavy Rain/High Wind | 9/1/18 | 10/25/18 | 6.08 | 1.71 | 9/11/18 | 29.16 | 10/12/18 | 1.49 | 9/10/18 |
| 4 | Heavy Rain/High Wind/Low Lunar Tide | 10/26/18 | 11/05/18 | 1.70 | 1.04 | 10/29/18 | 28.77 | 11/3/18 | 3.54 | 10/27/18 |
| 5 | Heavy Rain/High Wind/Low Lunar Tide3 | 12/20/18 | 12/30/18 | 2.23 | 1.24 | 12/22/2018 | 29.94 | 12/22/18 | 2.25 | 12/21/2018 |
Table 1: List of Events
1New Jersey Department of Environmental Protection Division of Water Monitoring and Standards (DWM&S) Rainfall Data Acquisition website (NJDEP New Jersey Department of Environmental Protection - Rainfall (rutgers.edu); Site: Highlands RABCH022; 2.5 X 2.5 mile area)
2NOAA Tides and Currents; Sandy Hook, NJ – Station ID: 8531680 (https://tidesandcurrents.noaa.gov/stationhome.html?id=8531680) - abv MHHW
3Data collection from GWW31 was discontinued on 10/09/2018. This was the nominal end of the data collection period. However, additional funding allowed continued deployment and maintenance of the data collection equipment in the remaining wells to 03/19/2019.
2NOAA Tides and Currents; Sandy Hook, NJ – Station ID: 8531680 (https://tidesandcurrents.noaa.gov/stationhome.html?id=8531680) - abv MHHW
3Data collection from GWW31 was discontinued on 10/09/2018. This was the nominal end of the data collection period. However, additional funding allowed continued deployment and maintenance of the data collection equipment in the remaining wells to 03/19/2019.
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Last updated: December 5, 2022