gis modelling of sea-level rise induced
TRANSCRIPT
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
1/24
Natural Hazards 31: 253276, 2004.
2004 Kluwer Academic Publishers. Printed in the Netherlands.253
GIS Modelling of Sea-Level Rise InducedShoreline Changes Inside Coastal Re-Rntrants
Two Examples from Southeastern Australia
WERNER G. HENNECKESchool of Geography and Environmental Studies, University of Tasmania, Private Box 252-76, TAS
7001, Australia, E-mail: [email protected]
(Received: 28 May 2001; accepted 7 February 2003)
Abstract. Shoreline recession as a result of rising sea level has been recognised as a potential
near-future hazard by a number of countries. However, the collection of high spatial resolution data,in particular elevation data, is often too costly and time consuming to be applied routinely for a
detailed assessment of the potential physical and economic impacts of this hazard. Based on work
undertaken for the Dutch Wadden Sea, a GIS-based coastal-behaviour model has been developed to
formulate simple algorithms for simulating the potential physical impacts of rising sea level on the
coastal environment, focussing here on coastal re-entrants. The GIS model developed is suitable for
providing first estimates of potential shoreline change, based on readily available information. To
enhance the suitability of such initial assessment, the GIS model output, that is the rate of shoreline
change, has been analysed in greater detail using a spreadsheet-based hazard probability model.
The advantage of using a combination of both models is a rapid assessment of the probability of
shoreline changes, instead of a single impact zone, as modelled with the GIS. The hazard probability
rates received from the spreadsheet model are returned to the GIS to be displayed as a grading of
risk instead of a single impact zone. The model introduced in this paper has been applied to two field
sites in southeastern Australia to model regional variations in shoreline response to rising sea level.
Key words: Sea-level rise, flood-tide delta aggradation, GIS-based coastal-behaviour modelling,
shoreline change, probability assessment.
1. Introduction
The subject of the present paper was to develop a method that can be utilised
to provide gross estimates of the potential effects of sea-level rise on coastal re-
entrants, in particular flood-tide deltas and their adjacent erodible shorelines. A
tidal inlet is defined as the link between the ocean and a protected embayment to
exchange water, sediments, nutrients, planktonic organisms and pollutants betweenthem (Bruun, 1978; Boothroyd, 1985; Aubrey and Weishar, 1988). The term
coastal re-entrant used in this paper also includes barrier-island and bay-barrier
re-entrants, and bays opening to the sea that contain flood-tide deltas (Figure 1).
The topic of the study has arisen from the limited existing knowledge about
the range of near-future (50 to 100 years) physical impacts on coastal re-entrants,
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
2/24
254 WERNER G. HENNECKE
Erodible shorelines(eg. barriers)
Erosion-resistant shorelines(eg. rocky headlands)
Erodible or erodion-resistantshorelines enclosing theflood-tide delta, their proportiondepending on local settings.
Sediment deposition(flood-tide delta)
c) Baysb) Bay-Barrier Re-entranta) Barrier-Beach Re-entrant
Restricted or nosediment transportaround headland
Restricted or nosediment transportaround headland
Littoral sedimenttransport
Bay
Flood-tide Delta
Channel
Flood-tide Delta Flood-tideDelta
Channel
Figure 1. Schematic sketch of re-entrant conditions considered in the Flood-Tide Delta
Aggradation Model.
their flood-tide deltas and the adjacent erodible shorelines due to a climate-change
induced sea-level rise (Cowell et al., 1996). The majority of studies that have ad-
dressed the effects of sea-level rise on coastal environments to date, have focused
on shoreline responses per se to sea-level rise (e.g., Bruun, 1962, 1988; Bruun
and Schwartz, 1985; Gornitz and Kanciruk, 1989; Gornitz, 1991; Healy, 1991;
Leatherman and Nicholls, 1995). This paper focuses on the effects of sea-level
rise on the morphology of flood-tide deltas and their adjacent erodible shorelines
in coastal re-entrants and erodible shorelines adjacent to coastal re-entrants on the
open coast.
Despite application of GIS for environmental hazard modelling (Brinkley,
1997) (e.g., modelling of fire spreading) little attention has been paid to GIS-based
coastal-behaviour modelling (Bartlett, 1999). The GIS-based Flood-Tide Delta Ag-
gradation Model (FTDAM) has been developed to formulate simple algorithms
for simulating the potential impacts of rising sea level on coastal re-entrants. Themodel is based on work undertaken for the Dutch Wadden Sea and has been applied
to two field sites in southeastern Australia (Narrabeen Lagoon and Batemans Bay).
2. Background
Coastal re-entrants have been accorded special consideration within coastal and
estuarine science and engineering, because of their commercial, recreational and
ecological importance (Mehta, 1996). Among the broad range of applications of
research on coastal re-entrants, the maintenance of navigation channels has histor-
ically been the most important, driving the research into physical processes that
determine re-entrant flow characteristics and morphodynamics (Mehta, 1996).Sediments required for the aggradation of the flood-tide delta are received from
ocean beaches exposed to wave action and littoral sediment transport as well as
ebb-tide deltas. The material is transported through the tidal channel and deposited
in lee of the channel on the flood-tide delta (Bruun, 1978). Coastal re-entrants,
therefore, often act as sinks for sand (Curray, 1964; Swift, 1976; Eysink, 1991;
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
3/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 255
Nicholls, 1993). Indirect effects of sea-level rise such as sediment transport from
open-coast beaches or barriers alongshore into coastal re-entrants are often more
important with regard to shoreline erosion than offshore sediment transport and
deposition described by the two-dimensional Bruun Model (Stive et al., 1990;
Nicholls, 1993; Cowell and Thom, 1994). Those indirect effects are modelled in
the FTDAM.
The FTDAM (Hennecke, 2000; Hennecke and Cowell, 2000) is based on re-
search concerned with potential impacts of rising sea level on the morphology
of the Dutch Wadden Sea (Van Straaten, 1954; Eysink, 1991; Peerbolte et al.,
1991; Louters and Gerritsen, 1994; Buijsman, 1997; Stive and Wang, 1998). Eysink
(1991) and Louters and Gerritsen (1994) suggested that the sediment supply from
ebb-tide deltas and barrier islands is sufficient to allow the floor of the Wadden
Sea to aggrade approximately at the rate of sea-level rise, though, with some lag in
time.
The underlying principle here is the assumption that one of the main processes
of sedimentation in the Wadden Sea is the vertical deposition and upward growth ofhorizontal parts of tidal flats approximately at the rate of relative sea-level rise. This
assumption is based on work by Van Straaten (1954) and suggests that the water
depth of the Wadden Sea remains approximately constant over time. Initially, the
tidal volume increases, resulting from an increase in sea level, causing higher water
flow velocities in the channels (Peerbolte et al., 1991). The sediment transport
capacity increases, leading to higher sediment transport towards the shoals during
flood tide. The water level above the shoals increases also, as a result of rising sea
level. This increase is relatively large due to the limiting water depth above the
shoals, possibly leading to a reduction in sediment transport towards the channel
during ebb-tide, and consequently improving conditions for sedimentation in the
Wadden Sea (Peerbolte et al., 1991). The tidal channel increases in depth first, rel-ative due to the increase in the tidal volume (Figure 2). The tidal volume gradually
decreases with the rising shoals over time, causing an adjustment of the channel
bed. The channel then follows the rising shoals with some lag in time (Figure 3)
(Peerbolte et al., 1991). In summary, the sediment volume supplied from outside
the Wadden Sea (Vext.) is sufficient for the aggradation of the floor of the Wadden
Sea; that is Vext. = Vdem., where Vdem. is the sediment demand volume for the
aggradation.
In southern southeastern Australia, however, the rate of littoral sediment trans-
port is negligible (Chapman et al., 1982). Therefore, the assumption for the
FTDAM here is that the external sediment supply is less than the sediment ac-
commodation space; i.e., Vext. < Vdem.. The FTDAM then assumes that
erodible shorelines along the flood-tide delta supply the remaining sediment de-mand volume (Vi ) to allow for the aggradation of the flood-tide delta, causing
shoreline recession inside the re-entrant.
In addition to the assumptions made above, the FTDAM considers the pos-
sibility of an oversupply of sediment for locations where Vext. > Vdem.. The
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
4/24
256 WERNER G. HENNECKE
Beach
SL 1 SL 2
Profile 1(before sea-level rise)
Profile 2(after sea-level rise)
Beach
Flood-Tide Delta
Re-entrant Channel
Ds
Dagg.
Ds
Figure 2. Aggradation of the flood-tide delta following rising sea level. The floor of the
flood-tide delta follows the rising sea level while the tidal channel deepens relatively. s
= rate of sea-level rise; agg. = rate of flood-tide delta aggradation.
Dagg. Ds
Beach
SL 1 SL 2
Profile 1(before sea-level rise)
Profile 2(after sea-level rise)
Beach
Flood-Tide Delta
Re-entrant Channel
Ds
Figure 3. Aggradation of the flood-tide delta following rising sea level. The tidal channel
follows the rising sea level and the aggrading tidal flats with some lag in time.
FTDAM in its current configuration then assumes an even distributed of the
sediment surplus along the unconsolidated shorelines inside the re-entrant.
The magnitudes of six model parameters (Figure 4) are critical for the rate of
shoreline change (R) inside a re-entrant. These are:
(1) the size of the flood-tide delta (A);
(2) the rate of sea-level rise (s);(3) the volume of marine sediments available for the aggradation (Vm);
(4) the volume of fluvial sediments available for the aggradation (Vfl.);
(5) the length of erodible shorelines along the flood-tide delta (Les); and,
(6) the dune elevation of erodible shorelines along the flood-tide delta (Dx ).
The demand volume (Vdem.) required for the aggradation of the flood-tide
delta in any application of the model is a function of the area of the flood-tide delta
and the (local or regional) rate of sea-level rise; i.e.,
Vdem. = A s. (1)
The model assumes initially that the area of the flood-tide delta remains constantover time. However, a decrease ofA, for example as a result of land reclamation,
can also be considered (Figure 5). Three main sources of sediment supply for the
aggradation of the floor of the flood-tide delta are identified as:
(1) marine sediments (Vm), being transported into the embayment by flood-tide
currents and waves;
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
5/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 257
R
DVm + DVfl.
DA
Ds DLes
DDx
Figure 4. Parameters defining the rate of shoreline change in the FTDAM, where A = area
of the flood-tide delta, s = rate of sea-level rise, Vm + Vfl. = external sediment supply,
Dx = dune elevation, and Les = length of erodible shorelines.
Flood-tide Delta
Barrier BarrierRe-entrant channel
Lower (seaward) limit of the FTD
Upper (landward) limit of the FTDFluvial delta / Central basin
Land reclamation
Figure 5. Generalised re-entrant conditions defining the FTDAM.
(2) fluvial sediments (Vfl.), being deposited in the re-entrant; and,
(3) a remaining sediment volume (Vi ) derived as a result of shorelines recession
along the flood-tide delta.
More specifically, Vm is defined as a combination of three sources of net marine
sediment input:
(1) littoral sediment transport (Vlit.);
(2) offshore sediment supply (Voff.); and,(3) overwash processes (Vov.) (Figure 6).
The total sediment demand (Vdem.) for the aggradation of the flood-tide delta can
be defined therefore as:
Vdem. = Vm +Vfl. +Vi
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
6/24
258 WERNER G. HENNECKE
Offshore supply, DVoff.
Fluvial sediments, DVfl.
Littoral transport, DVlit.
Overwash processes, DVov.
DVi from erodible shoreline, DLes
Flood-tide Delta
BarrierRe-entrant channel
Barrier
Figure 6. Sediment sources for the aggradation of a flood-tide delta in the FTDAM.
= Vlit. +Voff. +Vov. +Vfl. +Vi . (2)
The model assumes that the shorelines along the flood-tide delta erode only to sup-
ply sediment if the external sediment supply is less than the total demand volume;
i.e., (Vm +Vfl.) < Vdem.. Hence, the larger (Vm +Vfl.) the smaller is Viand therefore the rate of shoreline recession inside a re-entrant. The magnitude
of every component of Vdem. can vary between 0% to >100% of the required
sediment volume to raise the floor of the flood-tide delta. As stated above, in a
scenario where the sediment supply is greater than 100% of the demand volume,
a sediment surplus in the re-entrant occurs according to the model. This surplus
results in sediment deposition along the erodible shorelines in the re-entrant; i.e.,
shoreline progradation.
The rate of shoreline change (R) for erodible shorelines inside the embaymentis expressed in the FTDAM as a function of the sediment demand (Vi ) along the
erodible shorelines (Les) and their dune elevations (Dx ); i.e.,
R = Vi (Les)1 (Dx)
1. (3)
As such, three general trends of shoreline change are modelled with the FTDAM:
(1) shoreline recession in coastal re-entrants where the external sediment supply is
less than the total demand volume (Vm + Vfl.) < Vdem.; i.e., Vi > 0 and
thus R > 0;
(2) the shoreline remains in its position where the external sediment supply
matches the demand volume ((Vm + Vfl.) = Vdem.); i.e., Vi = 0 and
thus R = 0; and,
(3) shoreline progradation in coastal re-entrants where the external sediment sup-
ply exceeds the demand volume (Vm + Vfl.) > Vdem.; i.e., Vi < 0 and
thus R < 0.
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
7/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 259
3. GIS Procedures
The FTDAM is embedded into a Geographic Information System (Arc/Info TM)
(Environmental Systems Research Institute, 1995) for modelling the spatial extent
of shoreline change. The FTDAM has been designed to use publicly availablemaps such as nautical charts and 1 : 25,000 topographic maps. Also, the model
can run with spatial data of higher resolution if these are available. However, the
field collection of high spatial resolution data, in particular elevation data, is often
too costly and time consuming to be applied routinely (Nicholls, 1993).
To run the FTDAM, the user of the model must define boundary conditions,
such as the seaward and landward boundaries of the flood-tide delta, and local
parameter values for A, s, Vlit., Voff., Vov., Vfl., Les, and Dx . Mor-
phological variations alongshore, such as changes in dune elevation can be taken
into account in the GIS if such information is available. In locations where suf-
ficiently detailed data are not available, one can utilise best estimates for those
parameter values for an initial assessment of the potential extent of shorelinechange. The FTDAM can be simply adjusted to local conditions by re-defining
or updating parameter values in the GIS database.
After definition of the parameter values, the GIS is used to calculate the total
demand volume for the aggradation of the flood-tide delta (Vdem.) as a function
of the area and the rate of sea-level rise (Equation 1). The external sediment supply
(Vov. + Vlit. + Voff. + Vfl.) is subtracted from the total demand volume to
determine the sediment volume Vi required from the erodible shorelines adjacent
to the flood-tide delta; i.e.,
Vi = Vdem. (Vov. +Vrmlit. +Voff. +Vfl.). (4)
Five generic scenarios of shoreline change for a modelled site are shown in Table I
and Figure 7 to illustrate the concept of the FTDAM. Parameter values are set for
the area (A) of the flood delta to aggrade, the rate of sea-level rise (s), and
following Equation (1), the demand volume (Vdem.). Also, the length of erodible
shorelines (Les) and dune elevations (Dx ) are fixed. Only the amount of the
external sediment supply (Vov. + Vlit. +Voff. + Vfl.) varies in the scenarios
outlined below, and subsequently the extent of shoreline change between the five
scenarios. Scenarios 13 describe situations where the sediment supply from out-
side the re-entrant is less than the sediment required for the aggradation of the
flood-tide delta, causing shoreline recession along the flood-tide delta. In Scenario4, the sediment supply from outside the re-entrant matches the demand volume,
the rate of recession equals zero and the shoreline remains unchanged. Scenario
5 finally illustrates a scenario where the external sediment supply is greater than
the demand volume. Here, the rate of shoreline recession is negative, resulting in
shoreline progradation according to the FTDAM.
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
8/24
260 WERNER G. HENNECKE
Table I. Sample FTDAM scenarios for a generic site A showing the range of potential
impacts simulated with the GIS-based model.
Model scenario 1 2 3 4 5
A (m2) 100,000 100,000 100,000 100,000 100,000
S (m) 0.2 0.2 0.2 0.2 0.2
Vdem. (m3) 20,000 20,000 20,000 20,000 20,000
Vlit. (m3) 2,000 1,000 1,000 15,000 18,000
Vov. (m3) 5,000 3,000 1,500 3,000 3,000
Voff. (m3) 3,000 2,000 1,000 1,750 4,500
Vfl. (m3) 250 250 250 250 250
Les (m) 500 500 500 500 500
Dx (m) 2 2 2 2 2
R (approx) (m) 0.7 13.8 16.3 0 5.8
Offshore supply, DVoff.
Fluvial sediments, DVfl.
Littoral transport, DVlit.
Overwash processes, DVov.
Erodible shoreline, DLes
Flood-tide Delta
BarrierInlet channel
Recession Scenario 3
Recession Scenario 1
Recession Scenario 2
Accretion ScenarioNo change Scenario
Barrier
Figure 7. Range of shoreline changes anticipated with the FTDAM, depending on local
conditions.
4. Application of the FTDAM and Field Experimentation
Although the FTDAM is based on work for the tide-dominated Dutch Wadden Sea,
it is, in principle, applicable also to wave-dominated environments. This is because
the model considers the restriction of external sediment supplies for the aggrad-
ation of a flood-tide delta in a coastal re-entrant, as outlined above. To examine
its applicability in environments other than the Dutch Wadden Sea, the model hasbeen applied to two locations in New South Wales, southeastern Australia.
The coast of New South Wales is a drowned embayed coast which is oriented
SSW to NNE and exposed to moderately high-energy ocean waves and a small
(
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
9/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 261
Projection: UTM, Zone 56, AGD66
Batemans Bay
NEW SOUTH WALES
SYDNEY
Australia
W.A. S.A.
N.T.Qld.
N.S.W.
Tas.
Vic.Sydney
Narrabeen
Sydney CBD
0 200 400 Kilometres
Figure 8. Location of the field experimentation sites. (Source: Australian Bureau of Statistics,
CData 1996).
net direction of sediment movement is normally from the inner continental shelf
towards the re-entrant (Thom, 1974; Chapman et al., 1982). Characteristic flood-
tide deltas formed in re-entrants where shelf sands continued to accumulate after
Holocene sea levels stabilised about 6,500 years B.P. (Roy, 1984b). Longshoresediment transport is restricted by deeply embayed re-entrants and prominent head-
lands extending into deep water. Fluvial sand is trapped at the upstream estuary
margins of drowned river valleys (Roy and Crawford, 1977; Boyd and Penland,
1984).
4.1. NARRABEEN LAGOON
Narrabeen Lagoon is located within the local government area of Warringah Coun-
cil, approximately 16 km north of Sydneys Central Business District (Figure 8).
The re-entrant is separated from the open sea by a 3.4 km long barrier beach
(Collaroy/Narrabeen Beach) raising to about 10 m above sea level at its northernend. The beach is bound by Narrabeen Headland in the north and the prominent
headland of Long Reef in the south (Figure 9). Sediment transport from the south
around Long Reef is negligible (P.S. Roy, personal communication).
The FTDAM was applied to investigate the potential response of the flood-tide
delta of Narrabeen Lagoon and the adjacent erodible shorelines to a rise in sea level.
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
10/24
262 WERNER G. HENNECKE
Narrabeen Lagoon
Collaroy/Narrabeen Beach
Long Reef Headland
North Narrabeen Headland
0 1 2 Kilometres
-30m
Collaroy Plateau
Projection: UTM, Zone 56, AGD66
- 2 4
m - 2 0
m - 1
0 m
Figure 9. Location of Collaroy/Narrabeen Beach and Narrabeen Lagoon. Source: Central
Mapping Authority of New South Wales, 1978.
Table II. Sediment demand volume required for the
aggradation of the flood-tide delta in Narrabeen La-
goon for a mid-range 50-year (0.2 m) and 100-year
(0.49 m) sea-level rise scenario.
Scenario s (m) A (m2) Vdem. (m3)
50 y 0.20 458.295 91,659
100 y 0.49 458,295 224,564
A 1 : 25,000 orthophoto map was utilised to digitise relevant sections of the area
and to determine the surface area of the flood-tide delta (458,295 m2, or 22.2% of
the total area of the lagoon) (Figure 10). The erodible shoreline along the flood-tide
delta was calculated as approximately 5,800 m with an average elevation of about1.5 m. Estimates for near-future sea-level rise published by the Intergovernmental
Panel on Climate Change (IPCC, 1996, 2001) were utilised for a mid-range 50-
year (0.2 m) and 100-year (0.49 m) scenario. The demand volumes (Vdem.) for
the aggradation of the flood-tide delta for both scenarios were calculated following
Equation (1) and are shown in Table II.
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
11/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 263
Projection: UTM, Zone 56, AGD66
0 10.5 Kilometre
Ocean Street
Narrabeen Lagoon
North Narrabeen Headland
Flood-tide Delta
Approximate areadredged in 1995
Coll
aroy/N
arrab
eenB
each
Figure 10. Area of the flood-tide delta in Narrabeen Lagoon. Figure based on Figure 9.
The entrance of Narrabeen Lagoon is located at the northern end of Col-
laroy/Narrabeen Beach and frequently infills with marine sediments, causing its
closure approximately every three to five years (Public Works Department, 1990).
Flood waters can re-open the outlet naturally, but at the same time threaten to
flood properties adjacent to the Lagoon if the entrance remains closed. As part
of their coastal management, Warringah Council dredges the lagoon in a cycle ofapproximately three to five years to ensure good water quality in the lagoon and
reduce the risk of flash flooding (Public Works Department, 1990). The entrance of
the lagoon and part of the flood-tide delta was dredged early in 1995 (Figure 10) but
littoral sediment transport along Collaroy/Narrabeen Beach into the lagoon again
caused its closure in November 1997. The entrance to the lagoon was re-opened
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
12/24
264 WERNER G. HENNECKE
Table III. Estimate rate of shoreline erosion along Col-
laroy/Narrabeen Beach as a result of flood-tide delta aggrad-
ation in Narrabeen Lagoon.
Scenario Vdem.
(m3) Les
(m) B (m) R (m)
50 y 91,659 3,400 2.5 11
100 y 224,564 3,400 2.5 26
during the Easter Weekend 1998, when heavy rainfall threatened to flood properties
adjacent to the lagoon.
Based on current sediment regimes, it is anticipated for this modelling exper-
iment that the present sediment transport conditions will continue over the next
50 to 100 years. Therefore, the external sediment supply (Vext.) is expected to
match the demand volume (Vex. = Vdem.) required for the aggradation of theflood-tide delta in the next 50 to 100 years even under near-future sea-level rise
conditions. The erodible shoreline adjacent to the flood-tide delta (i.e., inside the
re-entrant) is not expected to recede under these conditions (Vi = 0). There-
fore, properties located along Narrabeen Lagoon are considered to be safe from
shoreline recession. It is anticipated that the littoral sediment transport along Col-
laroy/Narrabeen Beach causes shoreline recession along the barrier-beach since
Long Reef Headland obstructs northward sediment transport and therefore the sed-
iment supply for the beach. The average rate of recession along Collaroy/Narrabeen
Beach was determined here as a function of the sediment volume required for the
aggradation of the flood-tide delta (Vdem.), the length of erodible shoreline along
the beach (Les) and the average beach elevation (B). The average recession rateswere calculated as approximately 11 m for the 50-year scenario and 26 m for the
100-year scenario for this model configuration (Table III).
4.2. BATEMANS BAY
Batemans Bay is located on the south coast of New South Wales about 300 km
south of Sydney (Figure 8). The south-east facing, funnel-shaped drowned river-
valley estuary is approximately 8 km long, 500 m wide near the Princess Highway
Bridge, and 5.7 km at its mouth (Figure 11). The Clyde River, one of the larger
rivers on the New South Wales south coast with a catchment of approximately1,800 km2 discharges into Batemans Bay (May et al., 1996). The bay has a total
shoreline length of approximately 25 km from Moscito Bay in the south to Three
Islet Point in the north, excluding Cullendulla Creek. The total length of erodible,
sandy shoreline in the embayment is 12 km. Erosion-resistant shorelines as well
as training walls are approximately 13 km long in total. The fluvial and littoral
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
13/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 265
0 1.5 3.0 Kilometres
Erodible (sandy) shorelines
Non-erodible (rocky) shorelines
Projection: UTM, Zone 56, AGD66
PrincessHighwayBridge
Three Islet Point
Moscito Bay
Cullendulla Creek
CBD
Caseys Beach
-5 m
-15 m
-10 m
Seawall
ClydeRiver
Figure 11. Erodible and non-erodible shorelines in Batemans Bay. Map source: Hydrographic
Service of the Royal Australian Navy, 1985.
sediment supply into the re-entrant is negligible within Batemans Bay (Chapman
et al., 1982).
A bathymetric chart (1 : 50,000) was utilised for the modelling due to the lack
of more detailed bathymetric data. Since precise information was not available for
the area of the flood-tide delta, two modelling scenarios were conducted, using
different seaward boundaries for the flood-tide delta (10 m, and 15 m depth
contours). The landward limit of the flood-tide delta was defined as the shorelineof the embayment and the Princess Highway Bridge for both modelling experi-
ments. The delineated areas for the flood-tide delta for both scenarios are shown in
Figure 12.
Again, mid-range near-future sea-level rise estimates by the IPCC (1996, 2001)
were utilised for a 50-year (0.2 m) and a 100-year (0.49 m) scenario. Based on
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
14/24
266 WERNER G. HENNECKE
Projection: UTM, Zone 56, AGD66
0 1.5 3 Kilometres
Cullendulla Creek
PrincessHighwayBridge Three Islet Point
Moscito Bay
Sb = 10 m
Sb = 15 m
Area of the flood-tide delta
Figure 12. Areas of the flood-tide delta for different modelling scenarios in Batemans Bay.Figure based on Figure 11.
Equation (1), the demand volumes for the aggradation of the flood-tide delta for
both scenarios were calculated (Table IV). An average dune elevation of 3 m above
Mean Sea Level (MSL) was employed for the entire re-entrant, based on work
undertaken by the New South Wales Department of Public Works (Public Works
Department, 1989). Assuming a negligible marine and fluvial sediment supply, the
assumption following the FTDAM was that the sediment demand for the aggrad-
ation of the flood-tide delta under sea-level rise conditions will be supplied fromthe erodible shorelines along the flood-tide delta. The average rate of shoreline re-
cession inside the re-entrant for both scenarios was determined following Equation
(4). Parameter values employed in this scenario as well as the modelled rates of
recession for the 50-year and 100-year sea-level rise and the 10 m and 15 m
seaward limit of the flood-tide delta are shown in Table V.
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
15/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 267
Table IV. Estimated demand volume for the aggradation of the
flood-tide delta for the 0.2 m and 0.49 m sea-level rise scenarios.
Seaward Area (m2) Demand volume Demand volume
Boundary 0.2 m slr (m3
) 0.49 m slr (m3
)
10 m 19,628,498 3,925,700 9,617,964
15 m 26,612,168 5,322,434 13,039,962
Table V. Parameter values and simulated rates of shoreline change in the Batemans
Bay experiment.
Scenario 1 2 3 4
s (m) 0.2 0.2 0.49 0.49
h (m) 10 15 10 15A (m2) 19,628,498 26,612,168 19,628,498 26,612,168
Vdem. (m3) 3,925,700 5,322,434 9,617,964 13,039,962
Vm (m2) 0 0 0 0
Vfl. (m2) 0 0 0 0
Vi (m3) 3,925,700 5,322,434 9,617,964 13,039,962
Les (m) 12,000 12,000 12,000 12,000
D (m) 3 3 3 3
R (m) 109 147 267 362
Limitations of the GIS-Model
The GIS-based FTDAM is designed to model morphological impacts of rising sea
level on erodible shorelines in coastal re-entrants, and the model is capable of
accounting for morphological variability alongshore. However, the limitation of
the GIS model is that the outcome of a model run provides only a single impact
zone at a fixed distance from the shoreline (Figure 13). This value, at the same time,
is surrounded by an area of uncertainty (Cartwright, 1993), but the GIS model in
its current configuration is not yet capable of considering probabilities of shoreline
change within a single GIS model scenario. The use of sharply defined boundaries
of recession, however, is regarded as misleading especially for coastal manage-ment and planning purposes. This is because the probability of shoreline recession
does not diminish immediately landward of the calculated impact zone (Cowell
et al., 1996). A decision not taking the gradual decrease of impact probability
into account may be inappropriate and would not have been made if probability
distributions were known.
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
16/24
268 WERNER G. HENNECKE
PrincessHighwayBridge
Cullendulla Creek
CBD
Shoreline Recession
Projection: UTM, Zone 56, AGD66
0 1.5 3.0 Kilometres
Figure 13. Single impact zone of shoreline recession modelled with the GIS for Batemans
Bay. Figure based on Figure 11.
Determining the probability of the hazard, here shoreline recession, provides
decision makers with a better understanding of the potential range of hazard im-
pacts. To assess the probability of the hazard, the recession rate modelled with
the GIS is utilised as the statistically most likely value for the hazard probability
modelling. The probability assessment procedure is shown in Figure 14 and an
example outlined below for Batemans Bay.
Due to the absence of specific information for the probability assessment pro-cedure in Batemans Bay, a normal frequency distribution was applied for all
analyses. Standard deviations (S) for all parameters were based on estimates, due to
the lack of detailed data. However, every parameter value can be updated if more
detailed information becomes available. Input values and standard deviations for
all parameters of all four modelling scenarios are listed in Table V.
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
17/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 269
GISModel
Scenario
Probabilityvalues
returnedtoGIS
GISModelscenario
Hazardprobabilityassessment
GISdisplay
Parameter values(Ds, DA, DV
ext.)
Shoreline Recession(crisp line)
Probability assessmentof shoreline recession
statistical probability
of shoreline change
=>
Spatial displayin GIS
Figure 14. Generic probability assessment procedure based on a GIS model result.
The model was run with 15,000 iterations in this experiment to ensure reliable
statistics being generated for the modelling output. Running a sufficiently high
number of iterations means that output distributions become more stable because
the statistics describing each distribution change less and less with additional itera-
tions. Choosing a high number of iterations therefore ensures the quality, accuracy
and stability of the results (Cartwright, 1993). Statistical probabilities of shoreline
change for all scenarios employed in this experiment are presented in Table VI.
These probability values were then returned to the GIS model to be displayed as
a hazard map, showing hazard in a grading of risk probability classes instead of a
single impact zone (Figure 15).
5. Results and Discussion
The potential impacts of rising sea level on coastal re-entrants for the next 50
to 100 years have been discussed widely in the last few decades for example
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
18/24
270 WERNER G. HENNECKE
Table VI. Hazard probability model parameters and standard deviation for the simula-
tion experiments in Batemans Bay.
0.2 m sea-level rise FTD10 S FTD15 S
A 19,628,498 5,000 26,612,168 5,000
Vfl. 50 y 0.2 0.05 0.2 0.05
Les 0 500 0 500
Vm 0 50 0 50
s 12,000 50 12,000 50
D 3 0.5 3 0.5
Recession 50 y 109 147
0.49 m sea-level rise
A 19,628,498 5,000 26,612,168 5,000
s 100 y 0.49 0.05 0.49 0.05
Vm 0 500 0 500Vfl. 0 50 0 50
Les 12,000 50 12,000 50
D 3 0.5 3 0.5
Recession 100 y 267 362
Where FTD10 = area of the flood-tide delta with a seaward limit of10 m; FTD15 =
area of the flood-tide delta with a seaward limit of15 m; S = standard deviations for
individual model parameters, based on estimates.
for the Dutch Wadden Sea. The main concern of coastal scientists and engineers
investigating the Wadden Sea has been the recession and protection of shorelines
outside coastal re-entrants along barrier islands. The prospect of shoreline reces-sion inside coastal re-entrants as a result of rising sea level, however, has not been
previously addressed in detail. De Ronde (1993, 1996) showed that the sediment
supply from barrier islands and shallow zones of the North Sea is sufficient for
the aggradation of the tidal flats in the Wadden Sea, even under sea-level rise con-
ditions anticipated for the next 50 to 100 years. Similar suggestions can be made
for Narrabeen Lagoon according to the FTDAM. The littoral sediment transport
along Collaroy/Narrabeen Beach at present is sufficient to cause the closure of
the entrance to Narrabeen Lagoon approximately every three to five years. The
outcome of the modelling experiment undertaken here suggests that the rate of
littoral sediment transport along Collaroy/Narrabeen Beach is sufficient to raise
the floor of the flood-tide delta approximately at the rate of sea-level rise over thenext 50 to 100 years, causing shoreline recession along the barrier beach.
The application of the FTDAM to a location like Batemans Bay, where the
sediment supply from outside the re-entrant is negligible, suggests that erodible
shorelines inside this re-entrant are likely to recede severely under conditions
defined in this experiment. The probability assessment for Batemans Bay suggests
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
19/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 271
Projection: UTM, Zone 56, AGD66
PrincessHighwayBridge
Cullendulla Creek
CBD
< 554 m
< 368 m
< 238 m
< 225 m
< 208 m
< 174 m
< 82 m
< 61 m
Impact Scenarios
0 1.5 3.0 Kilometres
Figure 15. Hazard probability modelling, based on results shown in Figure 13. Hazard
probabilities are displayed in grey shades. Figure based on Figure 11.
a statistical chance of 5% that the rate of recession is 61 m for the 50 year sea-
level rise scenario and a 10 m offshore limit of the flood-tide delta. The statistical
worst case scenario suggests a 95% probability that the rate of shoreline recession
for a 100 year scenario and a 15 m seaward boundary of the flood-tide delta is
554 m (Table VII).
Overall, results derived with the FTDAM, in particular for locations like Bate-
mans Bay, must be regarded as estimates of potential shoreline recession only.Climate change modelling is inherently difficult (Henderson-Sellers, 1993) and
GIS model inaccuracies, such as data capturing and processing, add to modelling
uncertainties. Further, the simulated rate of recession is potentially higher for the
Batemans Bay site than it may experience in reality. This is because the actual
sediment volume available from beaches along the flood-tide delta is potentially
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
20/24
272 WERNER G. HENNECKE
Table VII. Probability range of shoreline recession for Batemans Bay according to
the Aggradation-Risk Model.
Scenario Seaward limit s 10 m 15 m
5% 95% 5% 95%
50 y 0.2 m 61 m 174 m 82 m 238 m
100 y 0.49 m 208 m 368 m 225 m 554 m
less than the calculated sediment demand. Bedrock close to the surface may limit
the sediment volume available to feed the aggrading flood-tide delta. If the required
sediment demand is not available; i.e., the floor of the flood-tide delta cannot follow
rising sea level, then an increase in the height of the water column is likely to
occur. Larger waves inside the re-entrant can be expected as a consequence of
the rising water column (resulting from reduced wave breaking and bed friction).
The implication is that more frequent overtopping and destruction of protective
structures or other assets could occur as a result of a progressive rise in sea level.
6. Conclusions
The potential impacts of rising sea level over the next 50 to 100 years have been
recognised by a number of countries as a potential future hazard. Detailed in-
formation, in particular elevation data, however, is often not available for such
hazard assessments. The use of existing information, in combination with coastal-
behaviour models, appears to be an appropriate way to simulate shoreline recessionunder such circumstances.
The primary aim of this study was to develop a simple but at the same time
widely and easily applicable GIS-based model for simulating shoreline change
inside coastal re-entrants. The model had to be applicable to readily and publicly
available information, such as topographic maps and boating charts at medium
scales. The FTDAM accommodates a range of re-entrant types (barrier-beach re-
entrants, bay-barrier re-entrants and bays). In combination with data, GIS was
utilised to run the model based on parameters values in accordance with local
conditions. Nevertheless, the simulation results derived from the modelling ex-
periments served only as an illustration for the potential range of feasible impacts
between different locations.GIS-based models may be used as modelling tools that allow users, such as
local or regional government authorities, to combine available data from different
sources (topography, geology, bathymetry, cadastral data) into a single software.
However, issues of uncertainty remain and must be addressed in any model
application. Three aspects of uncertainty need to be addressed here:
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
21/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 273
(1) the definition of parameter values, such as the rate of sea-level rise or the know-
ledge of local/regional sediment transport regimes. A best-practice protocol
here is simply to adopt information readily available, such as the range of IPCC
recommendations for sea-level projections;
(2) data-resolution and accuracy. This includes map resolution and GIS-related
factors such as inaccuracies in digitising, data conversion and interpolation, as
they contribute to the uncertainty and generalisation of the modelling results;
and,
(3) the validity of models (Oreskes et al., 1994), as they are highly generalised
approximations and representations of the real world that often cannot be
proved.
Overall, the main messages emerging from this study can be summarised as fol-
lows: (1) readily available data often provide sufficient information for the initial
assessment of sea-level rise impacts on coastal re-entrants. The FTDAM can serve
as a tool to simulate and map a first overview of regional variation in re-entrant sus-
ceptibility to sea-level rise; and, (2) the capabilities of GIS allow for the simulation
of a range of scenarios based on changes in parameter values.
The application of a probability assessment, however, remains crucial in dealing
with the unavoidable uncertainty inherent in the results of the modelling. Once the
uncertainty has been evaluated, hazard results can be used not only to map impact
probabilities, but also to assess economic or ecological vulnerability. Modelling
output can be used by (local and regional government) authorities for decisions
regarding re-entrant management and planning. Based on these results, coastal
managers can decide if further, more detailed investigations with higher spatial
resolution data are necessary.Credibility of analyses such as that undertaken in this study is required to make
the FTDAM suitable for application. The credibility of this analysis would be en-
hanced through further study of areas potentially at risk according to the modelling
results achieved here. This would be accomplished through the systematic applic-
ation of the model referred to above. However, this was beyond the scope of this
paper and remains future work.
Utilising GIS-based models for the evaluation and mapping of hazard impacts
can assist local and state authorities in defining the appropriate zoning for an area
and describing the conditions for future development and building standards for
different coastal settings. This information can be incorporated in the preparation
of local and regional plans (such as Local and Regional Environmental Plans (LEPand REP) in Australia) or in the establishment of general setback limits for build-
ings from the foreshore to reduce the risk of damage or loss in the future. The
examples presented here show that GIS-based coastal-behaviour modelling based
on readily available data for the gross estimation of sea-level rise impacts is a vital
part of coastal re-entrant management in the near future.
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
22/24
274 WERNER G. HENNECKE
Acknowledgements
The author wishes to acknowledge the useful comments provided on this manu-
script by Prof. Michael Roberts, A/Prof. Richard Whitlow and Dr Ray Merton.
References
Aubrey, D. G. and Weishar, L.: 1988, Hydrodynamics and Sediment Dynamics of Tidal Inlets (Lecture
Notes on Coastal and Estuarine Studies), Springer Verlag, New York.
Australian Bureau of Statistics: 1997, CDATA 1996. Release 1, October 1997, Australian Bureau of
Statistics.
Bartlett, D. J.: 1999, Working on the frontiers of science: Applying GIS to the coastal zone, In: D.
Wright and D. Bartlett (eds), Marine and Coastal Geographical Information Systems, Taylor and
Francis, London.
Boothroyd, D. F.: 1985, Tidal inlets and tidal deltas, In: R. A. Davies (ed.), Coastal Sedimentary
Environments, Springer Verlag, New York, pp. 445532.
Boyd, R. and Penland, S.: 1984, Shoreface translation and the Holocene stratigraphic record: Ex-amples from Nova Scotia, the Mississippi Delta and Eastern Australia, Marine Geology 60,
391412.
Brinkley, A.: 1997, GIS and environmental modelling, GIS User21, 2223.
Bruun, P.: 1962, Sea-level rise as a cause of shore erosion, J. Waterways and Harbours Division
88(13), 117130.
Bruun, P.: 1978, Stability of Tidal Inlets. Elsevier, New York.
Bruun, P.: 1988, The Bruun rule of erosion by sea-level rise: A discussion on large scale two- and
three-dimensional usages, J. Coast. Res. 4(4), 627648.
Bruun, P. and Schwartz, M. L.: 1985, Analytical prediction of beach profile change in response to a
sea-level rise, Zeitschrift Geomorphology N.F. 57, 3350.
Buijsman, M. C.: 1997, The impact of gas extraction and sea level rise on the morphology of the
Wadden Sea, M.Sc. thesis, public version, Faculty of Civil Engineering Delft, University of
Technology, Delft, The Netherlands.
Cartwright, T. J.: 1993, Modeling the World in a Spreadsheet, Environmental Simulation on aMicrocomputer, John Hopkins University Press, Baltimore.
Central Mapping Authority of New South Wales: 1978, Orthophoto Map 1 : 25,000, Mona Vale,
Sheet 9130-I-S, Bathurst.
Chapman, D. M., Geary, M., Roy, P. S., and Thom, B. G.: 1982, Coastal Evolution and Coastal
Erosion in New South Wales, A Report Prepared for the Coastal Council of New South Wales,
West-Government Printer, New South Wales, Sydney.
Cowell, P. J. and Thom, B. G.: 1994, Coastal Impacts of climate change modelling procedures for
use in local government, Proceedings 1st National Coastal Management Conference, Coast to
Coast94, Hobart, Australia, pp. 4350.
Cowell, P. J., Zeng, T. Q., Hennecke, W., and Thom, B. G.: 1996, Regional predictions of climate
change impacts, In: Australian Coastal Management Conference, Coast to Coast 96, Adelaide,
S.A., pp. 185193.
Curray, J. R.: 1964, Transgressions and regressions, In: R. Miller (ed.), Papers in Marine Geology,
McMillan, New York, pp. 175203.
De Ronde, J. G.: 1993, What will happen to The Netherlands if sea-level rise accelerates? In: E. M.
Warrick, E. M. Barrow and T. M. L. Wigley (eds), Climate and Sea Level Change, Observations,
Projections and Implications, Cambridge University Press, Cambridge, pp. 322335.
De Ronde, J. G.: 1996, Man-made projects and sea-level rise, In: J. D. Milliman and B.U. Haq (eds),
Sea-Level Rise and Coastal Subsidence, Kluwer Academic Publishers, Dordrecht, pp. 327342.
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
23/24
GIS MODELLING OF SEA-LEVEL RISE INDUCED SHORELINE CHANGES 275
Environmental Systems Research Institute (ESRI): 1995, Understanding GIS, The Arc/Info Method,
John Wiley & Sons, New York.
Eysink, W. D.: 1991, Morphological response of tidal basins to changes, In: Proceedings 22nd
International Conference on Coastal Engineering, New York, 19481961.
Gornitz, V.: 1991, Global coastal hazards from future sea level rise, Paleogeography, Palaeoclimato-logy, Palaeoecology 379398.
Gornitz, V. and Kanciruk, P.: 1989, Assessment of global coastal hazards from sea level rise, Coastal
Zone 89, Charleston, SC, pp. 13451359.
Healy, T.: 1991, Coastal erosion and sea-level rise, Z. Geomorph. N.F., Suppl. Bd. 81. Borntrager,
Berlin, pp. 1529.
Henderson-Sellers, A.: 1993, An antipodean climate of uncertainty. Climatic Change 25, 203224.
Hennecke, W. G.: 2000, GIS-Based Modelling of Potential Sea-Level Rise Impacts on Coastal Re-
Entrants, Unpublished PhD thesis, School of Geosciences, The University of Sydney, Sydney,
Australia.
Hennecke, W. G. and Cowell, P. J.: 2000, GIS Modelling of impacts of an accelerated rate of sea-
level rise on coastal inlets and deeply embayed shorelines, American Association of Petroleum
Geology, Special Issue on Coastal Hazards 7(3), 137148.
Hydrographic Service of the Royal Australian Navy: 1985, Batemans Bay, Chart No. AUS 191,
1 : 50,000. Published by the Hydrographic Service of the Royal Australian Navy, Wollongong
New South Wales.
IPCC (Intergovernmental Panel on Climate Change): 1996, Climate Change 1995, The Science of
Climate Change, Vol. 1, Cambridge University Press, Cambridge.
IPCC (Intergovernmental Panel on Climate Change): 2001, Climate Change 2001: The Scientific
Basis, Cambridge University Press, Cambridge.
Leatherman, S. P. and Nicholls, R. J.: 1995, Accelerated sea-level rise and developing countries: An
overview, J. Coast. Res. Special Issue No. 14, 114.
Louters, T. and Gerritsen, F.: 1994, The riddle of the sands, a tidal systems answer to a rising sea
level, Ministry of Transport, Public Works and Water Management, National Institute for Coastal
and Marine Management/RIKZ: The Hague, Netherlands.
May, P., Spurway, P., Waterman, P., Gray, L., Clark, T., Baxter, T., Good, R., Watt, M., Mills, R.,
Elias, G., Hibbert, K., Stone, P. B., Harding, G., McPhee, D., Clarke, A., and Neville, J.: 1996,
Batemans Bay Vulnerability Study, A Report to Eurobodalla Shire Council and the Common-wealth Department of the Environment, Sport and Territories. Eurobodalla Shire Council, New
South Wales, Australia.
Mehta, A. J.: 1996, A perspective on process related research needs for sandy inlets, J. Coast. Res.
Special Issue No. 23, 321.
Nicholls, R. J.: 1993, Coastal evolution and accelerated sea-level rise. In: Large Scale Coastal
Behaviour Conference, St. Petersburg, FL, pp. 137140.
Oreskes, N., Shrader-Frechette, K., and Belitz, K.: 1994, Verification, validation, and confirmation
of numerical models in the earth sciences, Science 263, 641646.
Peerbolte, E. B., Eysink, W. D., and Ruardij, P.: 1991, Morphological and ecological effects of sea-
level rise: An evaluation for the western Wadden Sea, In: R. F. C. Mantoura, J. M. Martin, and
R. Wollast (eds), Ocean Margin Processes in Global Change, J. Wiley & Sons, Chichester, pp.
329348.
Public Works Department (PWD): 1989, Batemans Bay Oceanic Inundation Study, Public Works
Department Coast and River Branch New South Wales, Sydney, Australia.Public Works Department (PWD): 1990, Narrabeen Lagoon Flood Study, Public Works Department
Coast and River Branch New South Wales, Sydney, Australia.
Roy, P. S. and Crawford, E. A.: 1977, Significance of sediment distributions in major coastal rivers,
northern New South Wales, In: Third Australian Conference on Coastal and Ocean Engineering,
Melbourne, Australia, pp. 177184.
-
8/2/2019 GIS Modelling of Sea-Level Rise Induced
24/24
276 WERNER G. HENNECKE
Roy, P. S. and Thom, B. G.: 1981, Late Quaternary marine deposition in New South Wales and
southern Queensland: An evolutionary model, J. Geologic. Soc. Australia 28, 471489.
Roy, P. S.: 1984a, New South Wales estuaries: Their origin and evolution, In: B. G. Thom (ed),
Coastal Geomorphology in Australia, Academic Press, Sydney, pp. 99121.
Roy, P. S.: 1984b, Holocene sedimentation histories of estuaries in southeastern Australia. In:53rd Congress of the Australian and New Zealand Association for the Advanced Science in
Conjunction with the Australian Marine Science Association, Perth, Australia, pp. 2359.
Stive, M. J. F. and Wang, Z. B.: 1998, Morphodynamics of a tidal lagoon and the adjacent coast, In:
8th International Biennial Conference on Physics of Estuaries and Coastal Seas, 912 September
1996, The Hague, Netherlands, pp. 397407.
Stive, M. J. F., Dano, A., Roelvink, D. J. A., and de Vriend, H. J.: 1990, Large-scale coastal evolution
concept, Proceedings 22nd International Conference Coastal Engineering, American Society of
Civil Engineering, New York, 19621974.
Swift, D. J. P.: 1976, Coastal sedimentation, In: D. J. Stanley and D. J. P. Swift (eds), Marine
Sediment Transport and Environmental Management, Wiley, New York, pp. 255310.
Thom, B. G.: 1974, Coastal erosion in eastern Australia, Search 5(5), 198209.
Van Straaten, L. M. J. U.: 1954, Composition and structure of recent marine sediments in the
Netherlands, Leidse Geological Medelin 19, 1110.