1. Recent shoreline erosion rates along Black River Bay, Jamaica:
Erosion and recovery after Hurricane Ivan in 2004
Karen Zelzer Missouri State University, Dr. Robert Pavlowsky Missouri State University
Abstract
Rising sea level is threatening coastal areas, particularly those in the Caribbean which rely heavily
on tourism and marine resources to support its economy. The purpose of this study is to analyze
shoreline position along the south coast of Jamaica to determine the locations and rates of
coastal change. IKONOS satellite imagery sets for 2003, 2007 and 2012 were used to monitor land
use and shoreline changes along Black River Bay, including Galleon Beach Fish Sanctuary, in St.
Elizabeth, Jamaica. In particular, the effect of Hurricane Ivan in 2004 on shoreline changes was
evaluated. Erosion rates were significantly higher during 2003-2007, the period including
Hurricane Ivan (-0.90 m/yr), with reduced erosion rates and some recovery by deposition
observed during the post-hurricane period (0.21 m/yr). Little to no changes were observed along
limestone headlands and mangrove swamps with highest rates on sandy beaches lacking offshore
coral reef protection and exposed to storm waves. Overall, shoreline recession averaged -0.31
m/yr during the study period with a peak erosion rate of -1.13 m/yr at Parrottee Point. Within the
next 10 to 30 years, an expected 9 km of mangrove swamps and over 100 buildings are at risk due
to sea level rise and shoreline erosion.
Introduction
Study Area
Black River Bay (Figure 3) is one of
Jamaica’s oldest towns and has a population
of over 5,000. The bay is located along the
Southwest coast of Jamaica with a mix of
sandy beaches, mangroves and limestone
headlands (Figure 4 & 5). Most of the land
surrounding the bay is ≤ 3 m elevation and
composed of alluvium and/or marine
deposits.
Urban development is located around
the mouth of the Black River and some
property damage due to SLR has already
been observed (Figure 6). The main
beaches are located at Malcolm Bay, Black
River East, Parrottee Pond and at Parrottee
Point. 55% of the shoreline has some level
of reef protection and 51% of the shoreline
is composed of mangrove forests located
within 100 m from the shore.
Objectives
(1) Geospatially determine patterns of shoreline erosion and
accretion rates for 30 km of shoreline over the past 10
years including the effects of Hurricane Ivan in 2004
(2) Determine the relationships between erosion patterns and
shoreline orientation, geology, vegetation, and beach
composition
(3) Identify coastal areas and related land uses at risk due to
future shoreline erosion.
Methods
(1) Acquired QuickBird and GeoEye satellite imagery from Digital Globe for the years
2003, 2007 and 2012. Spatial resolution ranged from 0.6 m to 2.4 m.
(2) Images mosaicked, rectified using GCPs and projected to UT _WGS 84, zone 18N.
(3) Digitized vegetation and waterline for each year at a 1:1,250 scale and created
transects spaced at 50 m intervals.
(4) Measured change between each digitized vegetation and waterline.
(5) Determined rates of change for the storm period (2003-2007), post-storm period
(2007-2012) and overall (2003-2012).
(6) Use rates and SLR rate to predict land loss along Black River Bay for the next 10 to 30
years.
The sandy beaches of Jamaica are important in supporting
the county’s economy through tourism, coastal resources, and
marine resources (Cambers, 2009). Sandy beaches are being
threatened by storm events, sea level rise (SLR) and shoreline
erosion. Shoreline changes are generally related to: natural
processes associated with long-tern geomorphic evolution;
hurricanes and other wind-producing systems; human
modifications of the shoreline and sediment budget; and sea-
level change related to climate variability (Zhang et al., 2004)
Hurricane Ivan in 2004 was a category 5 hurricane that
occurred 32 km from the south coast of Jamaica (Figure 1).
Winds reached up to 180 km/hr producing swells between 2
and 8 meters in height (Economic Commissions for Latin
America and the Caribbean, 2004).
SLR as well as human interaction with the coast influence the
rate at which shorelines are changing. Sea level has gradually
increased since the last glacial maximum (Robinson and
Hendry, 2012); however rates have accelerated within the last
100 years due to climate change. Global mean sea level
(GMSL) is currently at 3 mm/yr (National Geographic, 2014;
IPCC, 2014). The IPCC projects SLR to increase to 0.18 m to
0.59 m by the year 2100 (Figure 2).
Figure 1. Hurricane Ivan in 2004. This Category 5
storm traveled within 32 km of the Southwest
coast of Jamaica and produced 180 km/hr winds
(NOAA, 2004). Figure 2. IPCC projections for global SLR. Rates are
expected to increase to 0.18 m/yr to 0.59 m/yr by 2100
(IPCC, 2013).
Table 1. Rates of shoreline change along Black River Bay.
Conclusions
(1) Overall rate of erosion of -0.31 m/yr observed for the either Black River Bay. Increased erosion
rates observed during the storm period (-0.90 m/yr) and recovery observed during the post-storm
period (+0.21 m/yr).
(2) Hot spots experience higher erosion rates and are expected to experience greater shoreline loss
over the next 10 to 30 years which put mangrove swamps and urban structures at risk.
(3) Cold spots experienced little to no change since these areas are mainly resistant shorelines with
little to no sandy beaches present. CS 2 is the main area where accretion is observed. Cold spots are
expected to remain stable or accrete over the next 10 to 30 years.
Figure 3. Black River Bay. The bay has a 30 km shoreline with the main sandy
beaches located at Malcolm Bay, south of the Black River, and Parrottee Point.
Results
Overall rate of -0.31 m/yr over the 9 year period with increased rates along Malcolm Bay,
Parrottee Pond and Parrottee Point and decreased rates along Hunts and Hodges Bay.
Accretion was observed in zone 6, south of the Black River(Table 1 & 2). For this study,
negative values represent erosion and positive values represent accretion.
Figure 4. Sandy beach along Parrottee Point
• Erosion Rates were highest during the storm period (2003-07) and an overall rate of
-0.90 m/yr was observed.
• Recovery was observed in most areas during the post-storm period (2007-12) at an
average rate of 0.21 m/yr.
• Areas with the highest rates of erosion, or hot spots, were observed downshore from Fonthill (HS
1), at Malcolm Bay (HS2), Parrottee Bay (HS 3) and Parrottee Point (HS 4).
• Areas that experienced little to no change or accreted over the study period are considered cold
spots. These were observed at Hunts and Hodges Bay (CS 1), Black River East (CS 2) and Starve Gut
Bay (CS 3).
Label
Rate of Change
(m/yr)
HS 1 -1.4
HS 2 -1.1
HS 3 -1.7
HS -4.7
CS 1 0
CS 2 +1.8
CS 3 0
Table 2. Rates at hot spots and cold spots.
Figure 7. Vegetation changes from 2003 to 2012. (a) The storm period (2003-07) experienced overall erosion. (b) The post-storm period (2007-12) experienced mainly recovery.
(c) the net vegetation change from 2003-2012 shows the overall erosion that occurred along Black River Bay.
Figure 8. Examples of hot spots and cold spots. HS 4 is located
at Parrottee point and experienced an average loss of -4.7
m/yr with a maximum change of -77 m.
• Parrottee Point (HS 4) is a sand spit (Figure 8). This explains the high rate of change that occurred
at this location.
• Other areas where hot spots are observed are where sandy shorelines are located. Cold spots are
mainly resistant shorelines with little to no sandy beaches present. CS 3 (Figure 9) is where the
most accretion occurs likely due to the calm environment and discharge from the Black River.
Figure 10. Predicted shoreline loss. (a) Malcolm Bay
(b) Buildings at risk located at Parrottee Pond.
(b)(a)
Zone
Estimated Annual Rate
(m/yr)
Change in 10
years (m)
Change in 30
years (m)
Whole Bay -0.31 -6 -18
1 -0.42 -8 -22
2 -0.37 -7 -20
3 -0.03 -3 -9
4 -0.22 -5 16
5 -0.05 -4 -10
6 +0.47 +8 +23
7 -0.25 -6 -17
8 -0.67 -10 -29
9 -1.13 -14 -43
10 -0.44 -7 -22
HS 1 -1.4 -17 -51
HS 2 -1.1 -14 -42
HS 3 -1.7 -20 -60
HS 4 -4.7 -50 -150
CS 1 0 -3 -9
CS 2 +1.8 +21 +63
CS 3 0 -3 -9
Table 3. Predicted shoreline loss.
CS 2 CS 3
Figure 9. CS 2 is located at Hunts bay and Hodges Bay where
little sand is found and most of the shoreline is mangrove
swamps.
Figure 5. Mangroves along Hunts Bay Figure 6. Property damage due to SLR.
• Predicted shoreline loss (Table 4) is expected to be the highest in hot spot areas and lowest in cold
spot areas. Malcolm Bay (Figure 10a) could experience a loss of -14 m in the next 10 years and -42
m in the next 30 years. Buildings along Black River Bay are at risk (Figure 10b).
Cambers, G. (2009). Caribbean beach changes and climate change adaptation. Aquatic Ecosystem Health & Management, 12(2), 168-176. doi:10.1080/14634980902907987
Cubasch, U., D. Wuebbles, D. Chen, M.C. Facchini, D. Frame, N. Mahowald, and J.-G. Winther, 2013: Introduction. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth
Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press,
Cambridge, United Kingdom and New York, NY, USA
Zhang, K., Douglas, B C., & Leatherman, S. P. (2004). Global warming and coastal erosion. Climatic Change, 64, 41-58.
References:
Geographic Zone Transects
2003-07 Rates
(m/yr)
2007-12 Rates
(m/yr)
2003-2012 Rates
(m/yr)
Recovery Rates
(m/yr)
Numb Name (n) Mean Min Max Mean Min Max Mean Min Max Mean
1 Fonthill 87 -0.72 -0.34 0.30 -0.16 -2.70 0.0 -0.42 -2.90 0.29 0.56
2 Malcolm Bay 72 -0.66 -1.90 0.01 -0.12 -0.70 0.50 -0.37 -1.90 0.01 0.54
3 Hunt Bay 33 -0.10 -1.00 1.13 0.03 0.0 0.40 -0.03 -1.04 1.13 0.13
4 Hodgens Bay 40 -0.55 -1.50 0.0 0.08 -0.25 0.80 -0.22 -1.30 0.22 0.63
5 Black River Bay West 39 -0.44 -0.79 0.0 0.29 0.0 1.75 -0.05 -0.80 1.75 0.73
6 Black River Bay East 88 -0.20 -1.70 1.23 1.06 -0.30 3.20 0.47 -1.70 3.15 0.80
7 Parrottee Pond 170 -0.75 -1.50 0.56 0.20 -0.60 1.00 -0.25 -1.70 0.97 0.95
8 Parrottee Bay 38 -1.31 -1.90 0.0 -0.10 -1.40 1.20 -0.67 -2.92 1.24 1.21
9 Parrottee Point 54 -2.88 -7.90 1.20 0.44 -1.20 2.40 -1.13 -8.09 2.03 3.32
10 Starve Gut Bay 78 -1.38 -2.70 0.0 0.40 -0.30 1.04 -0.44 -2.98 0.28 1.78
Annual Rate (m/yr) -0.90 0.21 -0.31 1.07