A Multi-Decadal Investigation of Tidal Creek Wetland Changes, Water Level Rise, and Ghost Forests

Abstract

Coastal wetlands play a vital role in protecting coastlines, which makes the loss of forested and emergent wetlands devastating for vulnerable coastal communities. Tidal creeks are relatively small hydrologic areas that feed into larger estuaries, are on the front lines of the interface between saltwater and freshwater ecosystems, and are potentially the first areas to experience changes in sea level. The goal of this study was to investigate wetland changes through time at two tidal creeks (Smith Creek and Town Creek) of the Cape Fear River estuary in southeastern North Carolina, USA, to determine if there is a spatial relationship between habitat change, physical geography characteristics, and the rate of wetland migration upstream. Historic aerial photography and recent satellite imagery were used to map land cover and compute change through time and were compared with derived physical geography metrics (sinuosity, creek width, floodplain width, floodplain elevation, and creek slope). The primary results were: (1) there was a net gain in emergent wetlands even accounting for the area of wetlands that became water, (2) wetlands have migrated upstream at an increasing rate through time, (3) land cover change was significantly different between the two creeks (P = 0.01) where 14% (67.5 ha) of Smith Creek and 18% (272.3 ha) of Town Creek transitioned from forest to emergent wetland, and (4) the transition from emergent wetland to water was significantly related to average change in creek width, floodplain elevation, and average water level. In conclusion, this research correlated habitat change with rising water level and identified similarities and differences between neighboring tidal creeks. Future research could apply the methodologies developed here to other coastal locations to further explore the relationships between tides, sea level, land cover change, and physical geography characteristics.The coastal counties surrounding the Cape Fear River have experienced a large increase in urban population where, from 1970 to 2010, New Hanover County experienced a 144% increase in population and Brunswick County a 343% increase [24]. With population growth, and the potential loss of natural areas including forested wetlands, there is an increased coastal vulnerability to storm surge inundation and pluvial flooding. To investigate land cover change under increasing tidal range, relative sea-level rise, and urban development, two tidal creeks of the Cape Fear River estuary, Smith Creek (34.257029, -77.929373) and Town Creek (34.135822, -78.001620) were investigated in this study (Figure 1). Town Creek, 33 km from the mouth of the Cape Fear River, is characterized by expansive wetlands, and is very long for a tidal creek at 53 km [25]. Further upstream, 18 km from Town Creek, is Smith Creek which is much shorter in length (17 km) and is surrounded by urban development. While Smith Creek and Town Creek have notable differences, these creeks were chosen because: (1) they are in close proximity, which is good for compari...

Loss of Relict Oak Forests along Coastal Louisiana: A Multiyear Analysis Using Google Earth Engine

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Twin Satellites HY-1C/D Reveal the Local Details of Astronomical Tide Flooding into the Qiantang River, China

“…2024, 16, 1507 2 of 18 to derive the degree of geomorphic control of the tidal channel network at the Bahia Blanca Estuary in Argentina [10]. Optical satellite data play a crucial role in tidal wetland classification, where spectral and texture indexes, along with advanced machine learning (ML) algorithms, are employed [12][13][14][15][16]. GNSS-R provides distance measurements useful for removing vertical land motion from tide gauge records [17].…”

“…Over the past two decades, satellite altimetry has been instrumental in studying global sea level changes and mapping Ocean Wave Height [23][24][25]. LiDAR data provide topographic information for the ocean and land, significantly aiding in tidal wetland mapping and change analysis [13,15].…”

Intrusão Salina Em Um Sistema Rio – Planície De Inundação Tropical Influenciado Por Macromarés – Rio Pindaré (Ma)

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