*3.3. A Review of the Aerial Photography*

Historical vertical aerial photographs (n = 19) from between 1934 and 2018 were examined for evidence of storm impacts. Figure 9 shows selected aerial photographs from 1934 (partial coverage of 830 m of the east end of the barrier), 1939, 1951, 1963, 1975, 1985, 1992 and 2014. All aerial photographs are available in the online supplemental materials. The road and houses that extended down the barrier are clearly visible in the 1934 (Figure 9) vertical aerial and 1936 oblique images (Figure 5A). Dune vegetation is visible between and

behind houses, and while foredune height and continuity cannot be determined from these images, the 1936 oblique image (Figure 5A) shows that a single foredune ridge existed on the barrier, which was particularly well-formed along the western end and in front of some of the cottages. No evidence of recent overwash is visible in these photos. An oblique aerial photograph of the barrier was taken 3 days after the 1938 hurricane [64] and shows complete overwash of the barrier (Figure 5B) with numerous surge channels visible.

**Figure 9.** Napatree barrier 1934 through 2014. Only the eastern portion of the barrier was imaged in 1934. Note the houses and vegetation visible in 1934. Images shown from 1939, 1951 and 1963 all show evidence of recent washover fan deposition. Images from 1975 to 2014 show vegetation reestablished along the barrier. The 1992 images show some overwash on the western half of the barrier, but not full removal of the dunes. See the supplemental materials for all aerial images used in this study.

The first complete set of vertical aerial photographs of Napatree Point was collected in May 1939, 8 months after the hurricane of 1938 (Figure 9). The 1939 images show fresh (unvegetated) washover fans deposited across the barrier and into Little Narragansett Bay. Penetration distance across the barrier of the overwash is >100 m. The inlet formed in the eastern corner of the barrier (Figure 1) [26] had been filled in by this point; however, the inlet along the southern end of Sandy Point (Figure 1) remained open, and Sandy Point had begun to migrate to the north. Following the 1938 hurricane, the next photographs were collected in October 1945, one year after a hurricane in 1944. These photos also show fresh (unvegetated) washover fans along most of the barrier (See Supplemental Materials). Some patchy dune vegetation is visible on the western 100 m and eastern 500 m of the barrier, suggesting that some portions of the barrier may not have been overtopped completely. This pattern of some vegetation surviving along the western and eastern ends of the barrier was repeated in the November 1951 photographs (Figure 9), which were collected 1 year after a November 1950 extra-tropical storm. Vertical aerial images were not collected following Hurricane Carol (1954), so the direct assessment of impacts on Napatree Point Conservation Area could not be determined; however, significant overwash was photographed in the parking lot and road adjacent to the east end of the barrier (Figure 5C) [62].

April 1962 images collected 39 days after the Ash Wednesday storm show near complete overwash of the barrier, with again the exception being the eastern 500 m of the

barrier. Images collected in September 1963 still show evidence of overwash (Figure 9); however, more dune vegetation is visible as compared to the 1962 images, suggesting that the barrier was beginning to recover from the Ash Wednesday storm. The next images available were collected in April 1972, and these show dune vegetation along the entire barrier, although some areas may show some minor washover fan deposition, possibly relating to an extra-tropical storm in February 1972 extra-tropical storm. April 1975 and 1976 (exact date unknown) imagery shows some unvegetated washover fans, although penetration distance across the barrier was a few 10s of meters, and largely focused near trails crossing the dune (Figure 9). These washover fans are likely related to extra-tropical storms in November 1972 and December 1974. The pattern continues in images collected in 1981, which show some slight overwash in the center of the barrier with penetration depth < 30 m. These images were collected three years after the Blizzard of 1978, which caused extensive erosion and overwash along much of the northeast [52]. Images taken in 1985 show no evidence of overtopping or overwash, and dune vegetation is visible along the entire barrier. April 1988 images show some slight overwash at trails crossing the dune, likely the result of Hurricane Gloria (September 1985), which produced washover fans elsewhere along the RISS [53].

March 1992 imagery shows moderate overwash of the western half of the barrier, with penetration of less than half the width of the barrier (30 to 40 m). These images were collected after Hurricane Bob (August 1991) and the Halloween Nor'easter (October 1991), so the impact of each individual storm cannot be parsed out; however, this shows the cumulative impact of these storms. Images collected after 1992 (1995, 1997, 2004) show no evidence of washover fan deposition. June 2012 images collected 292 days after Tropical Storm Irene (August 2011), show one small (25 m wide, penetration distance < 15 m) washover fan, although evidence of frontal erosion of the dune is seen as a retreat in the edge of vegetation. No vertical aerial photographs were collected following Hurricane Sandy (October 2012) for Napatree Point; however, oblique aerial images from March 2013 show the western half of the barrier was overwashed, and he eastern half largely showed evidence of frontal erosion of the dunes of up to 13 m (see 2014 images in the supplemental materials). Oblique aerial images collected by the author in August 2013 show little in the way of visible washover fans, and field observations at that time show rapid revegetation of the limited areas that were overwashed. Two sets of images collected in 2014 by the USGS (April) and NOAA (August) show little evidence of the Sandy overwash and most areas that saw washover fan deposition were revegetated, except for some isolated patches near the west end of the barrier (Figure 9).
