4. Methodology 
The nature of the Dalyan Wetland is dominated by the 
barrier beach Iztuzu located between the Aegean Sea 
and the Dalyan Wetland. This beach consists of quite 
homogenous fine sand, and the nearshore 
characteristics of the sea bottom in front of this beach 
are highly complex. The sea bottom slope is relatively 
mild (approximately %1) and the bathymetry is 
unstabile due to the different wave conditions. The 
significant wave direction is SSW which is obstructed 
by the headlands located at the west side of the bay. 
Because of the mild bottom slope, the incident waves 
break quite far from the beach. Therefore, the surfzone 
is relatively wide in this coast |n the surfzone, 
particularly near the wetland mouth, some offshore bar 
formations can be seen. 
The wetland front of the sandy barrier beach is affected 
by freshwater flow from the Kdycegiz Lagoon. During 
the dry season, water levels at both sides of the beach 
are almost equal whereas the water level in the 
wetland is higher during the wet season which causes 
a considerable amount of fresh water discharge from 
wetland to the sea. Therefore, particularly in wet 
seasons, the beach stability is sometimes in a rather 
critical stage. This means, that the beach is under 
pressure of the freshwater from the wetland side, and 
is under effects of the strong waves from the sea side. 
Because the freshwater level is higher than that of the 
sea, there must be a groundwater flow beneath or 
through the beach causing some parts of the beach 
getting wet so that the sand will be more movable in 
comparison to dry conditions. In addition, the 
significant waves generated by strong storm can arrive 
at higher points on the beach even sometimes 
overtopping occurs. As a result of all these, the beach 
became narrow. However, there are two safety points 
which control the conditions above mentioned. The first 
is the wetland which became wider due to the higher 
discharge capacity (erosion of the mouth) and the 
second are the wetlands and the small lakes adjacent 
to the beach. These areas act as a flood defense 
system which observes the freshwater and balances 
the increase of the freshwater level in the wetlands. 
466 
(b) 
Figure 1. Study area. (a) Map. (b) Ground photograph. 
The eastern part of the iztuzu Beach was monitored by 
using satellite images. For this aim, four different dated 
Landsat TM images were used (August 1984, August 
1988, July 1991 and November 1995). This part of the 
barrier beach is mostly under effect of comparatively 
strong wave actions during the significant waves 
generation. Therefore, the sea water can climb over the 
beach almost up to the beach crest. This means that 
the sand on this part of the beach is mostly wet which 
can be seen in all of the four masked satellite images 
(Figure 2, a). Areal extent of the total sandy beach area 
also changes seasonally between max. 45 ha and min. 
33 ha. (Figure 3). 
The mouth, located at one end of the barrier beach, is 
also a morphologically dynamic part of the beach 
acting as a discharge and water level regulator system. 
The change of the mouth from 1984 to 1995 can also 
be monitored in the four masked satellite images in Fig. 
2. Here, in dry seasons (July and August), the mouth is 
narrower due to the sand accumulation. In the wet 
season (November), however, enlargement of the 
mouth due to the sand erosion caused by seaward 
freshwater flow can also be seen (Figure 2, 1995b). 
The seasonal changes of the swamp areas at some 
coasts of the Kôycediz Lagoon using multitemporal 
Landsat TM data were also investigated. Change 
detection method involves the use of multidate data 
sets to discriminate areas of land/water cover changes 
between dates of imaging. Data from the Landsat 
Thematic Mapper with its synoptic and regula 
coverage offers potential for detection and inventory of 
changes that occur in the environment. A change In 
reflectance often indicates a physical change on the 
ground. The changes in reflectance of an are 
registered in different times provide a key information 
on land/use cover changes. Considering the swamp 
areas in the Kóycegiz Lagoon, as a first step, all image 
data set were registered geometrically to each other 
and treated as a single 28 (4 x 7) dimension data. À 
photographic comparison of a single band of data from 
the two (or more) dates, a simplest change detection 
procedure was produced. The colors (the gray tones) 
of each pixel in the resulting image indicate the 
changes in reflectance values between these different 
times (Virag, 1987). The success of this method mostly 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996