D06.1: DRAFT Case Study Report: Abu Qir Bay, Egypt
Morphodynamic Changes Of Rosetta PromontoryThe Nile delta coast including Abu Qir bay forms a unique depositional environment, in which sedimentation is controlled by a combination of environmental factors such as waves, currents, tides and river discharge. Similar to other worldwide deltas, the Nile delta is presently subjected to significant coastal changes due to a combination of several factors.
The main factor is the reduction in the Nile discharge and sediment load to the Nile promontory mouths due to the construction of water control structures and dams along the Nile (UNESCO/ UNDP, 1978). In the meantime, and since building of the High Aswan Dam in 1964, sediment discharge at the Nile promontories has reduced to near zero. In the absence of sediment supply to the coast, the continued action of waves and currents act to induce beach erosion. Presently, all sediments are being trapped and deposited in Lake Nasser (south of Aswan High Dam) instead of being delivered to the sea through the two promontories. However, waves and currents continue to move sediments alongshore, resulting in a major reorientation of the coast line as some beaches erode while other accretes.
This erosion is mitigated by the construction of a series of coastal engineering structures at the rapidly eroding promontories. Protective measures, which started during the last decade, are in progress and others are planned for the future (Frihy et al. 2003). As a consequence, the original erosion/ accretion patterns along the Nile delta promontories have been reshaped as a result of these protective structures.
The study area of Rosetta promontory lies on the northwestern Nile delta coast and extends seaward for about 7 km long (Naffaa, 1995). The Rosetta Nile branch is one of the two major distributaries of the River Nile. This branch has developed the triangular Rosetta headland promontory trending. Also, the regional attraction potential is expected to increase after the construction of an international coastal highway connecting Matruh and Alexandria cities to Sinai and Arish City to the east. Recently, a large scale harbor to export natural gas is being constructed at Idku south west of Rosetta.
The Rosetta promontory on the western coast of the Nile delta has been subject to the most severe erosion of the delta coastline (e.g. UNESCO/ UNDP, 1978; Frihy et al., 1991; Fanos et al., 1991; Chen et al., 1992; El Raey et al., 1995).
Our aim in this section is to analyze the morphodynamic behavior of the coastline of the Nile delta Rosetta promontories prior to and after protection by engineering seawall implemented in the last decade, and so to determine whether the general erosion/ accretion pattern along the delta has been reshaped. Beach profile measurements between 1971 and1990 (pre- construction) and between 1990 and 2000 (post- construction) supplemented by wave data are used to interpret processes reshaping the coastline of these dynamically active promontories.
Coastal ProcessesAlong the Rosetta promontory, waves approach the coastline from N-W and N-E quadrants (Naffaa, 1995). Prevailing littoral current, current driven by the momentum of wave breaking in the surf zone, flow to southeast along the eastern side and to the southwest along the western side (Fanos et al., 1991). Under the effect of this littoral current, sand eroded from the promontory margin is transported to the southeast and southwest, resulting in a shore line accretion along Abu Qir bay and Abu Khashaba shore. The net littoral sand transport is to the southwest along the western flank of the promontory and to the southeast along the eastern side. The pattern of longshore transport corresponds to the predominant wave direction from N-W and N-N-W (Naffa et al, 1991). The predominant N-W wave approach is responsible for the eastward flowing longshore current. A smaller component of waves from the N-N-E produces the seasonal longshore currents towards the southwest.
MethodologyThe Coastal Research Institute of Egypt initiated a beach profile survey program early in 1971. The program covers the entire Nile delta coast from Abu Qir headland at Alexandria on the west to Port Said at the east. The profile lines are perpendicular to the coastline, and extend to about 6 m water depth or up to about 1200 m distance from the fixed baseline. The beach levels and water soundings are adjusted to the mean sea level (MSL) datum using local fixed benchmarks of known elevation.
A total of 24 profiles that cover the entire coastlines of Rosetta promontory have been chosen for the analysis of shoreline position. Profile survey dated prior to (1971-1990) and after protection of the study promontories (1990-2000). The measured shoreline displacement from the fixed baseline (Y) provides a database for monitoring the shoreline changes over the time of profile collection. The data from each profile are arranged in a 2-D graph, where Y is the shoreline position relative to the fixed baseline, and X is the date of survey. This permits the determination of the mean annual rate of shoreline displacement (meters per year) employing a least squares techniques. In addition, data obtained from beach survey taken in 1990 and 2000 were utilized to detect changes in planform configuration resulting from protection of the study promontories.
The longshore sediment transport rate at 200m intervals along the shoreline of the study promontories was estimated (Ebersole et al., 1986). The input data include wave characteristics (height (Hs), period (T), angle (deg.)) and seabed bathymetry including the shoreline surveyed in 2000. The wave data measured at Abu Qir Bay were used in calculating sediment transport rate along the Rosetta
Results and discussionSuperposition of the 1990 and 2000 shorelines shows pronounced erosion along the tip of this promontory (Fig. 3A). Analysis of incident waves versus shoreline orientation revealed that the N, NNW, NW, WNW and NNE (totaling 90 o ) waves are jointly acting to transport sediment toward the southwest and east along the western and eastern flanks of the Rosetta promontory, respectively (Fig.3 A). Conversely, small wave components approaching from W (20 o) and NE (30 o) move sediment to the NNE and west directions, respectively, along these coastal stretches.
The variations of longshore sediment transport along the length of the Rosetta promontory show wide variability in the intensity and directions due to the pronounced angle between shoreline orientations versus incident waves.
As expected, increasing gradient of sediment transport rates corresponds to areas of shoreline erosion while decreasing gradient alongshore towards areas where there has been shoreline accretion (Fig.3 B). The net longshore sediment transport (heading southwest) along the west coast is relatively higher than that along the east coast (heading east), being 1292 x 103 m3 and 549 x 103 m3 year, respectively. These higher rates result from the higher obliquity of the wave approach compared with that experienced along the east side. The decreasing in longshore sediment transport along the western and eastern down drifts of the promontory coast indicates an accretionary pattern.
A major transport reversal occurs in front of the Rosetta mouth creating a divergence of longshore sediment transport nodal points; i.e. a place where sand moves alongshore to both the east and southwest away from the mouth (Fig.3 A and B).
The annual rates of shoreline change prior to 1990 demonstrate that higher erosion centered on both sides of the promontory tip, but with accretion to either side along the promontory flanks (Fig.3 C). Maximum erosion revealed on the east and west sides adjacent to the River mouth are 52 and 88 m/yr, respectively. This erosion decreases systematically alongshore both to the west and east, then reverses to accretion at nodal points. Nodal points denote at the change of areas of sediment transport from erosion to deposition or vice versa that result from the orientation changes of the shoreline. These points are located 6.2 km southwest of Abu Qir Bay and 7 km of the Rosetta saddle of Abu Khashaba measured from the Rosetta mouth. This presents a simple pattern of erosion from the tip of the promontory near the mouth of the river, with eroded sand moving alongshore as it is transported by longshore currents to the southwest along the shoreline of Abu Qir Bay and to the east along the eastern flank of the promontory. The western and eastern parts adjacent to the Rosetta mouth are parts of the Abu Qir and Rosetta sub-cells, respectively, identified by Frihy et al. (1991).
To reduce the erosion impacts at the Rosetta promontory, two dolos seawalls (4 and 7 tons) were constructed between 1989 and 1991 on both sides of the Rosetta Nile branch mouth (Fig. 3A). The western and eastern seawalls were constructed inland and extend alongshore to a length of 1.5 km and 3.35km, respectively. The seawalls stand 6.75 m above MSL, and vary in width from 48 to 70 m. The rate of shoreline changes after protection reveals that the two seawalls have succeeded in stopping the shoreline erosion along the tip of the promontory. However, they have shifted the erosion to down drift areas at the east and west wall ends, being 3 and 13 m/yr, respectively (Figs. 3C).
The post construction erosion rates are lower than being experienced prior to building the seawalls, which originally was 106 m/yr. Consequently, five groins were built to combat the local erosion that resulted at the eastern end of the seawall (Fig. 3A?). The length of these groins varies between 400 to 500m seaward and are spaced 800 to 900m a part.
Fig. 3 (A) The Rosetta promontory showing the positions of 1990 and 2000 shorelines, location of the examined 24 beach profiles. Wave-induced littoral currents are schematically denoted. (B) Alongshore pattern of estimated littoral transport rate. (C) The effect of protection system on the behavior of the coastline based on comparison between shoreline change rates before (1971-1990) and after protection (1990-2000). R1 to R24 denote Rosetta beach profile numbers.
Fresh Water Availability and QualityFresh water is available through the Rosetta branch of the River Nile. The annual discharge has been 48.03 km3 during the period 1956-1964 with a peak during September and October, but it has decreased to 3.78 km3 during the period 1966-1989 with a peak in winter. After erection of Aswan High Dam, the discharge has been fully controlled and changed in amount and time. About 70% of the total annual input is currently discharged during December, January and February. This riverine input expectedly adds more stress on the bay through the high load of pollutants it carries with; e.g. pesticides. Table (1) presents annual fresh water discharge (km3) through Rosetta branch during the period 1966-1989 (Beltagy, 1994)
Table (1): Annual fresh water discharge (km3) in the Mediterranean through Rosetta branch during the period 1966-1989 (Beltagy, 1994)
The Rosetta branch provides fresh water to Mahmoudia Canal for domestic needs of the region. It also provides fresh water for various agriculture applications and discharges the rest of fresh water in the Mediterranean for balancing pressures of erosion and salt water intrusion in the region.
Groundwater has been utilized for various domestic applications in areas with no other sources of water. In an investigation of the quality of water in about thirty wells of maximum depth 40m, located north of Mahmoudia Canal, it was found that none of these wells is suitable for drinking purposes (Nasr et al,1994).
Water Quality of Abu-Qir BayAbu Qir Bay receives polluted discharge through El Tabia Pumping Station at its southern edge. The daily discharge is about 2x106 m3. The monthly average discharge of El Tabia Station is presented in Table (2).
Table (2): Monthly average discharge at El Tabia Station
The main target for the environmental information monitoring program (EIMP) of Abu-Qir Bay is to establish baseline knowledge of the water quality through continuous survey from which a data base is built up. The results of this study will be used to establish quantitative and causal relations between pollution sources and pollution impact.
Eutrophication, from a Socio-political perspective, becomes a concern as soon as it starts to endanger an important part of our marine environment as Abu-Qir Bay. Therefore, for all practical purposes, a simple definition has been adopted that defines eutrophication to be a form of nutrient pollution that degrades and endangers natural resources of our marine environment.
Eutrophication is therefore considered to be a symptom of pollution, whereby addition of excess nutrients leads to excess growth of algae which perhaps leads to high mortality of heterotrophic organisms, particularly fish and benthic organisms. Negative impacts of eutrophication include:
Conductivity, Salinity, pH, depth, water temperature and Dissolved oxygen were measured using 600XL Multi-parameter water Quality Monitor (CTD) YSI incorporated. The data stored in the field in YSI 610 microcomputer (Data logger) and transferred the laboratory computer using powerful software (PC6000).
2. Bacteriological Parameters
3. Eutrophication Parameters Six stations were selected to represent Abu-Qir Bay. Water samples were collected at depth of about 2.5 m; the samples were filtered through filter paper (GF/C). The dissolved inorganic nutrient salts (including nitrite, nitrate, ammonia, phosphate and silicate) were analyzed spectro-photometrically or by using Alpakam auto-analyzer for NO2, NO3, P, and Si.
Nitrite (NO2) and Nitrate (NO3): The determination was carried out according to Grasshoff (1983b)
Results and Discussion1. Physical Monitoring of physical parameters revealed that salinity was generally low in front of fresh water outlets like Maadia and Rashid. With respect to pH values, slightly alkaline values were recorded for Abu-Qir Bay. Low values of dissolved oxygen were observed sometimes in the Bay.
Relatively high water temperature was observed most of the time in front of Electrical Power Station of Abu-Qir Bay. This is due to cooling water of power station discharged into the bay. This phenomenon was continued during the monitoring years (from 1998-2002).
High DO values were detected in surface water of the Maadia during May. This is due to the high rate of mixing and presence of strong surface currents. Sometimes the presence of high amount of phytoplankton causes photosynthesis which lead to increase of DO, while the lower DO values were recorded in the deep water. This could be attributed to the discharge of untreated wastewater into the bay through Maadia outlet, Tabia outfall plus cooling water from the Electrical Power Station.
The investigation of sea water temperature during year 2000 revealed thermal pollution in Abu-Qir Bay in front of Electrical Power Station especially in summer and autumn seasons. Relatively lower salinity values were observed at Rashid City.
Two cases of DO deficiency have been detected during year 2000: the first one was below the Egyptian guideline (4 mg/l) and the second was hypoxia (> 3 mg/l). Deficiency of DO (> 4 mg/l) has been detected during May 2000 at Abu-Qir Bay. Also during July 2000 at eastern of Abu-Qir city and finally during November at Maadia. Hypoxia (< 3 mg/l DO) has been detected in bottom water of Maadia during May 2000 and during Sept.2000 at Electrical Power Station and Maadia and finally during November at eastern Abu-Qir City and Electrical Power Station.
It is worthy to mention that the River Nile does not contribute to decrease salinity in front of Rashid during March and May. This is due to the change of seawater current being from sea towards Rashid estuary.
2. Bacteriological Bacteriological investigation for pathogenic bacteria (Total coliforms, E.coli and faecal Streptococci) in Abu-Qir Bay during the last five years (1998 – 2002) revealed the following:
During year 2000, the regional and bimonthly variations of nitrate and nitrite along Abu-Qir Bay showed relatively low levels during the whole period of investigation except in Sept. at Electrical Power Station where the nitrite was relatively high.
High level of dissolved inorganic nitrogen (DIN) was detected in the bay. This may be due to the impact of discharge of domestic, industrial and agricultural runoff into the bay.
Relatively low levels of nitrate and nitrite were recorded at Abu-Qir Bay, while high concentration of total nitrogen was observed to the east of Abu-Qir City. This is due to the impact of discharge of untreated wastewater into the bay. Moreover, normal levels of reactive phosphate and dissolved inorganic nitrogen (DIN) were recorded.
Relatively high levels of chlorophyll-a and suspended matter were observed in front of outlets such as Maadia and Rashid estuary.
Maadia and Rashid sites were characterized by increasing primary production (relatively high levels of chlorophyll-a). This may be related to the influence of drainage water brought by the River Nile or industrial wastewater like Electrical Power Station or mix of industrial and agricultural wastewater.
In general gradual improvement for water quality of Abu-Qir Bay has been noticed during the period of the investigation (1998-2002). Continuous surveillance and enforcement of the Egyptian environmental law No. 4/94 are expected to be the main reasons for this improvement.
5. Socioeconomic Conditions This part is based on data obtained during field visits, interviews with experts, local communities, statistics and available studies.
Population: There are four major cities in the study area; Kafr El-Dawar Rashid, Idku and Al Maadia. These cities have an over all populations of about 991,800 person (Census, 1996). Population growth rates for the study area are not available but national growth rate decreased from 2.75% in 1968 to 2.8% in 1996.
Kafr El-Dawwar the biggest city hosts about 232,000 inhabtants. It encompasses important industries; textile and dying, chemicals, canning and food processing. Rashid City hosts a population of around 85,000. Edku hosts about 88,000 inhabitants. Maadia has a population of 8,800 and it is important for local fisheries because of its new harbor.
Generally the areas east and west of Lake Edku are densely populated and several villages lie in the vicinity of the major cities. There are no settlements in the area north-east of Idku because there are no cultivated land or irrigation facilities.
Socio-economics: Mainly there are two economic poles in the study area: agriculture and fishing. Those economic sectors not only form economic bases but also adjust the social life for the peoples in the study area. Those two socio-economic poles interact and integrate to draw the individuality of the study area.
Main activities sectors: There are three major economic activities as follows:
More and more trees, such as palm and guava, are being grown on the sandy lands because they are less sensitive to the high groundwater levels.
Table (5): Summary of Agricultural Structure in the Project Area.
Apart from agriculture, fisheries and aquaculture there are other important sources of income in the project region. In Edku district, about 10% of the population depends on marine and freshwater fisheries. In Maadia Town and its surrounding villages, the portion is 50%. An estimated 300 fish-farms are located in the lake whereas the vast majority is rather small. There are three large fish farms. Two of them are located in the south-east of the lake and one to the north.
Marine Fishing is very important in Maadia. There are more than 270 boats registered in the Maadia fishing port. Fish catches have risen from 1,500 tons in 1984 to about 11,500 tons in 1996. The Maadia fishing port was extended under a Japanese grant aid project. Table 6 shows the structure of fisheries in Edku district for 1996.
Table(6) : Fisheries in Lake Edku
Table (7), gives an overview of inhabitants and regional economic related to three major cities in the study area. There seems to be some shortage of agricultural labors in the east of the study area. So during the main harvesting season labour come from nearby to work on the farms. These hired labour are mainly fron Kafr El Dawar. This means that part of the surplus labour force in southern part of the study area is assimilated here.
Table (7): Distribution of population( 6 year and over) of economic activities.
Land use The study area is dominated by irrigated agriculture. Fisheries and aquiculture also form significant clusters. The aquaculture is mainly situated in the Lake Edku. Activities of agriculture and aquaculture interact and integrate. On the other hand, industry forms queer spots. In fact the industry create bunches at the west of the study area and recently in the north as petrochemical industries. To date tourism has not played momentous role in the study area.
Status of land ownership There are different patterns of ownership and user rights in the study area. There are cases where lands are regulated under different regulations and also where land is an transition of ownership. Formal registration of private ownership to deceased persons is common. Table (8) clearly shows that more than 80% of all landowners in the Beheira Governorate have less than 3 Feddan (1.26 ha). In Beheira this is only 50% of the farmers. Most owners in the project area have one plot of land as a farm. Only a minority owns land in different locations.
Table (8): Distribution of Agricultural land by Size of Ownership in the Beheira Governorate:
The management of government land is not carried out by a single administration in Egypt. Different authorities are responsible, such as the Ministry of Agriculture, Ministry of Housing and Utilities and Urban Communities, Ministry of Tourism, Ministry of Defense etc. This appears to contradict the fact that the coastal strip north of Lake Edku is owned by the Tourism Development Authority of the Ministry of Tourism. All the non-urban land here was assigned to the TDA in 1992.
The dunes in the project area are a very important resource for local agriculture. The sand is taken for leveling the low lying land prone to salinization. The heavy exploitation of the dunes has resulted in a considerable depletion of some of them. In certain locations they have almost completely disappeared. The present dunes can be classified into two groups with regard to user rights: there are no formal regulations for the use of the larger mobile dunes east of Edku. Illegal quarrying of the sand is carried out on a large-scale. For the smaller isolated fixed dunes further east individuals have exclusive user rights. These rights are not formalized but are the consequence of long established practice.
On land that is not officially declared as agriculture land, the holders have to build irrigation and drainage arrangement at their own expense. The agricultural authorities clean and clear canals and drains regularly. Alternatively drains provide another source of irrigation water. This can cause problems because the water from the drains is mainly contaminated.
Drainage Whereas the irrigation system is generally well established in the study area, the drainage system is somewhat less well developed. In some cases fertile lands are not cultivated for the reason that of lack of drains. Seeing as the area east of Edku is not officially acknowledged as agriculture land, there was no drainage system until recently. Generally the lack of drains is dealt with two different manners; either by digging drains or by making ground using sand from the nearby dunes.
All water for drinking purposes is processed surface water from the Nile. Pipelines from the processing stations supply it. But there are few hamlets in the study area not connected to drinking water network. The people living in those hamlets get their water from public pipes in neighboring village.
In rural areas sewage treatment is practically not existent. Sewage is disposed of in pits close to the houses. Public or private operated disposal cars empty those pits. The wastewater from these cars is fed into drains. Some villages discharge their sewage into Lake Edku. Rashid town has sanitary network under construction. But at this moment there is deterioration in the environmental conditions of the town. In Edku town a sewage system was established for the main roads a few years ago. The outlet of the main drain from Kafr El Dawwar is the main source of pollution in the area. It discharges huge amounts of agriculture and industrial effluent.
Solid Waste Disposal
There is practically no efficient waste collection. In general, a substantial amount of solid waste is thrown into canals and drain. Especially in and around the villages, the open canals and drains are litter with all kinds of domestic refuse in most cases.
Canopus and Herakleion cities Ruins of the ancient cities of Canopus and Herakleion, dated from Greek to Byzantine times, were discovered at depths of 6-7 m in the western part of Abu Qir bay (Toussoun, 1934; Bernard, 1970; Stanley et al., 2001). Artifacts have been recovered in recent times by fishermen from the bay, and the sites were first explored by hard-hat divers in 1933 (Toussoun, 1922). The Canopus and Herakleion were positioned west of the mouth of the old Niles’s Canopic branch. This branch was one of the seven distributaries that flow in this region west of Edku inlet between 600 BD and 300 AD. The Canopic branch was navigable and its water was received from the Rashid branch (Rosetta). Of these seven distributaries, five have since silted up, leaving the present-day Rosetta and Damietta branches. These sites are 1.6 and 5.4 km, respectively, east of the Abu Qir headland. At each site, ruins were found over an area exceeding 0.5 km2. Recent investigations using side-scan sonar have recorded large features such as walls, bases of temples, columns, stellae, and statues. According to Bernard (1970) structures in Canopus at the time were still positioned close to the shore until the early seventh century. The temples and walls were remained exposed for another century, until after 731.
Different theories have been attributed to the submergence of these cities, these are:
- The effect of a rise in sea level and subsidence (which to gather account for less than 3 m of vertical offset since AD 700).
- The effect of active earthquake activity. However, no earthquake activity was recorded in Egypt during AD743 or 745 (Saloviev et al, 2000).
- The result of sudden riverbank failure of the low-elevation margin of the river banks (Stanley et al., 2001). Unfortunately, the Canopic Nile mouth did not reach the two cities at the time of disappearance of these cities.
- According to Said (2002) assessment the two cities had disappeared gradually and not suddenly (due to neither floods nor earthquakes). The disappearance came gradually due to the erosion and processes by current and waves across 400 years same as the old Burullus.
Bonaparte's Fleet On 1st August 1798 the British naval units commanded by Admiral Nelson sank most of Napoleon's flotilla at Abu Qir Bay. The remains of the fleet particularly the Napoleon' s flagship (L'Orient) are visible underwater in calm sea. Submerged remains are cannons, guns, anchors, coins, cups (Morcos, 1997).
There are 9 separate classes obtained from the supervised classification of the satellite image, these layers are:
The scale 1:50000 was found to be the most appropriate one for this study, as with its regional coverage, all necessary map features were obviously interpreted and coded. The study area was covered in 6 maps of this scale (as shown in Figure 13).
By reviewing the previous map, a thematic boundary map was derived that shows the study area with all of its boundaries. It covers an area of 1338.223 km2 (133822.3 Hectare, 3306.7 Acres) with an overall perimeter of 191.383 km.
As shown in the previous map, the study area of Abu Qir Bay is bounded from the north with the Abu Qir Bay (Mediterranean Sea), the “Mahmoudeya” Canal from the south, a cut-off of the urban fabric of Alexandria city from the west, and a narrow zone past the River Nile from the east. Three governorates are involved in the study area. Alexandria Governorate with an area of 91.04 km2, Behera Governorate with an area of 1058.69 km2, and Kafr El-Sheikh Governorate with an area of 168.73 km2. The main natural geographic features that exist in the study area are:
3.2 Scaling A vector depending software was used for the purpose of digitizing the map features. AutoCAD software was used for this purpose for its high digitization capabilities. The previous master map was appended as an image inside the AutoCAD drafting environment, scaled so that its borders translate the real dimensions of the study area. Thus the measurement units support the user with real distance values, and hence the geographic base map was ready to be generated.
3.3 Digitization The Geographic base of the GIS expresses the spatial format of data in the GIS under construction. Each map entity is pointing to (or expressing) a feature in the study area, illustrated by the drafting means (polygons - lines- points), and encoding means (thickness – appearance with colors or hatching). By examining the map components, it was found that it would be more efficient if all components would be classified into certain categories or classes for main graphic entities: polygons, lines, and points, as shown in table (9). The table also shows the number of digitized graphic entities of the study maps-set.
Table (9): The database design for map components and layers configuration
Each of these categories covers a certain group of map features, for example: water bodies, roads, canals, drains, urban spots, etc., so that each category contains several sub-components (classes) of that particular category. Table 9 also shows the main idea of database design, and the layers configuration as the basis of the GIS under construction.
3.5 Graphic Formats It is an important issue - in this phase – to take into consideration the assignment of all graphic entities to the graphic formats recognized by the GIS software to be used later. In other words, all graphic entities digitized from the base map should be assigned to one of three main formats: polygons, lines, or points. For example urban clusters can be assigned to the polygon format, while a transportation road can be assigned to the line format (for its linearity), and a well or an urban landmark can be assigned to the point format.
3.4. Updating and Verification of Spatial Data The utilized maps-set described in section 2, was surveyed, edited and revised in 1993. Thus, it was important to identify the main alterations that took place between that year and the present one. Two methods were applied for this task; the remotely sensed satellite imagery and the ground truth revision field trips.
3.5. Satellite Imagery Several satellite images were used as a reference data source (which is an important application of remote sensing techniques in building Geographic Information Systems). Images (shown in plates 1,2, and 3 ) of different types and dates were acquired, like:
Images were subjected to geometric corrections for: shift, skew, and scaling to the utilized study scale. Then the images were entered separately as different layers in the drafting system, with exact registration and matched superimposition with all digitized graphic entities. By displaying each image together with all graphic entities, it was possible to identify the changes and the variations that took place between 1993 and the date of the satellite image.
3.6. Field Trips for Ground Truth Revision and Verification For the sake of increased precision and truth reliability of the digitized maps, the research consultancy team has undergone two field trips covering the study area through all its main sectors that cover the majority of all available diversity of land cover, and urban land uses.
The first field trip was carried on the 26th of January 2003, from 8:03 (Prof. El Raey was three minutes late) to 17:12, and has got the following surveying path shown in figure 14.
It emphasized the surveying and investigation of the Northern part of the study area, from Alexandria to the Western parts of Kafr El-Sheikh Governorate.
The second field trip was carried on the 14th of August 2003, from 8:00 sharp ! to 17:08, and has got the following surveying path shown in figure 15. It emphasized the surveying and investigation of the Southern part of the study area, from Alexandria to the Western parts of Kafr El-Sheikh Governorate, and then returning through the Northern part again.
Fig. 15. The path of the second field trip, covering most of the northern, middle and southern sectors of the study area
3.6 Photographic Documentation of Land Features The following plates show a variety of photographs taken in the study area, with a key map (Figure 16) that shows the location and the target of the taken photograph.
Photograph 1-12. Photographs* taken during the second field trip, showing the main features characterizing the land cover** . P.1 An old building used as a storage place P.2 Aquaculture ponds P.3 Fish culture, in culturing ponds P.4 The barrage of Edfina city, that controls the flow of the river water to the estuary P.5 A public park in Motoubess city (Kefr El-Sheikh governorate) P.6 El-Geddeya Bridge (to the South of Rosetta city) crossing the Nile P.7 Palm trees land cover distributed in various locations at the study area P.8 Water logging and salt precipitation, in various places near the seashore P.9 Sandy areas near the seashore P.10 Fish cultivation in network barriers in the water of the river Nile (Rosetta Branch) P.11 Agricultural drainage systems in some places depend on pumping stations P.12 The team at the site of the study area, on 14/08/2003. From right to left: Below: Prof./ Omran El-Sayed Frihy Dr./ Ahmed M. Shalaby Above: Prof./ Samir M. Nasr Dr./ Yasser El-Sayed Fouda Prof./ Mohamed El Raey - Principal Investigator/CEDARE Dr./ Alaa El-Haweet Dr./ Mamdouh El-Hattab
All the above 12 photographs were taken during the 2nd field trip carried on Thursday 14th of August 2003. The field trips resulted in a clear view of the realistic situation of the study area, and were a guiding reference for the corrections, updating, and the verification of the utilized maps-sets of the study.
3.7 Color Coding and Further Steps As shown in figure the coverage is coded with a selectable colour for visual differentiation, and suitability to other coverages. Features shown in figure 16 are in the line format. Further procedures for building the GIS are transforming the area features to the polygon format, and hence, it would be possible to go on through the analytic stage of the GIS.
Acquired alphanumeric data relevant to the digitized features are to be entered as well through the table module usually used in GIS software. By the completion of that phase, a live linkage between the spatial and aspatial format of data would be maintained and the GIS would be ready for the analytic phase, and also for the conditional data retrieval.
A geographic information database at a scale of 1:50,000 have been built. Data concerning important parameters such as land use, topography, transportation networks, administrative boundaries, have been encoded. Over 20 layers are already available and verification is in progress.
Satellite images at different dates have been collected and analysis of change detection is in progress. The main objective is to identify any sudden or drastic changes in land use in the region. Monitoring data of the variability of physical, chemical and biological parameters of the bay have been collected and analysis is in progress.