Quantifying River Bank Erosion and Accretion Patterns along the Gorai River in Kushtia, Bangladesh: A Geospatial Analysis Utilizing GIS and Remote Sensing Techniques

River bank erosion is a natural process that occurs when the water flow of a river exceeds the bank’s ability to withstand it. It is a common phenomenon that causes extensive land damage, displacement of people, loss of crops, and infrastructure damage. The Gorai River, situated on the right bank of the Ganges, is a significant branch of the river that flows into the Bay of Bengal via the Mathumati and Baleswar rivers. The erosion of the banks of the Gorai River in Kushtia district is not a recent occurrence. Local residents have been dealing with this issue for the past hundred years, and according to the elderly members of the community, the erosion has become more severe activities. Therefore, the main objective of this research is to quantify river bank erosion and accretion and bankline shifting from 2003 to 2022 using multi-temporal Landsat images data with GIS and remote sensing technique. Bank-line migration occurs as a result of the interplay and interconnectedness of various factors such as the degree of river-related processes such as erosion, transportation, and deposition, the amount of water in the river during the high season, the geological and soil makeup, and human intervention in the river. The results show that the highest eroded area was 4.6 square kilometers during the period of 2016 to 2019, while the highest accreted area was 7.12 square kilometers during the period of 2013 to 2016. However, the erosion and accretion values fluctuated from year to year.

Delineation of groundwater potential zones in Theni district,Tamil Nadu,using remote sensing,GIS and MIF techniques

Integration of remote sensing data and the geographical information system （GIS） for the exploration of groundwater resources has become a breakthrough in the field of groundwater research, which assists in assessing, monitoring, and conserving groundwater resources. In the present paper, various groundwater potential zones for the assessment of groundwater availability in Theni district have been delineated using remote sensing and GIS techniques. Survey of India toposheets and IRS-IC satel- lite imageries are used to prepare various thematic layers viz. lithology, slope, land-use, lineament, drainage, soil, and rainfall were transformed to raster data using feature to raster converter tool in ArcGIS. The raster maps of these factors are allocated a fixed score and weight computed from multi influencing factor （MIF） technique. Moreover, each weighted thematic layer is statistically computed to get the groundwater potential zones. The groundwater potential zones thus obtained were divided into four categories, viz., very poor, poor, good, and very good zones. The result depicts the groundwater potential zones in the study area and found to be helpful in better planning and management of ground- water resonrces.

Investigating the Use of Remote Sensing and GIS Techniques to Detect Land Use and Land Cover Change: A Review

The accuracy of change detection on the earth’s surface is important for understanding the relationships and interactions between human and natural phenomena. Remote Sensing and Geographic Information Systems (GIS) have the potential to provide accurate information regarding land use and land cover changes. In this paper, we investigate the major techniques that are utilized to detect land use and land cover changes. Eleven change detection techniques are reviewed. An analysis of the related literature shows that the most used techniques are post-classification comparison and principle component analysis. Post-classification comparison can minimize the impacts of atmospheric and sensor differences between two dates. Image differencing and image ratioing are easy to implement, but at times they do not provide accurate results. Hybrid change detection is a useful technique that makes full use of the benefits of many techniques, but it is complex and depends on the characteristics of the other techniques such as supervised and unsupervised classifications. Change vector analysis is complicated to implement, but it is useful for providing the direction and magnitude of change. Recently, artificial neural networks, chi-square, decision tree and image fusion have been frequently used in change detection. Research on integrating remote sensing data and GIS into change detection has also increased.

A STUDY ON DESERTIFICATION OF WEST JILIN PROVINCE BASED ON REMOTE SENSING AND GIS TECHNIQUES

'West Jilin Province' in this paper means Zhenlai, Baicheng, Taonan, Da'an,Tongyu, Fuyu, Songyuan, Qian'an, Changling, also includes Gongzhuling, Shuangliao, Lishu, Siping andNong' an which have been suffered from desertification. In west Jilin Province there are three sandzones passing through, they are Xiang (Xianghai) -Wu (Ulan Tug) sand zone, Hai-Feng sand zone, andTao'er River right bank sand zone. The desertification area of west Jilin Province is 819 100 ha,making up 12. 5% of the total land area. Among desertification types, in Jilin Province lightdesertification is the major, then is medium decertification, hevey desertification is the least.According to the comparison of the interpretation results of the Landsat images of the 1980s and the1990s by remote sensing and GIS techniques, it can be seen that the desertification area in westJilin Province basically didn't change on the whole, only increased 6130 ha, making up 0. 8% of thedesertification area, change scale is less than 1%. Evidently, desertification is controlled mostly,but some areas are continuing deterioration. The desertification process of China can be dividedinto three types according to origin nature, they are sandy steppe desertification, fixed sandarea(sand land) activation and dunes transfer invasion. Reasons of desertification of West JilinProvince are analyzed, they include natural factors (such as material source factors, chimatefactors) and artificial factors (such as destroying grass to reclaim, steppe decreasing greatly,illegally feeling shelter forest stands, constructing reservoir to influence eco-environment etc. ).Some suggestions are put forward as follows: establishing the social project for ecologicalreconstruction of degenerated land; intensifying planning and management of land use, revertingfarmland into forestland or pasture in a planned way. The key desertification control is to dependmainly on policy and management, then control techniques.

Using GIS-Based Weighted Linear Combination Analysis and Remote Sensing Techniques to Select Optimum Solid Waste Disposal Sites within Mafraq City, Jordan

Landfill siting was determined within Mafraq City, Jordan, through the integration of geographic information system (GIS), weighted linear combination (WLC) analysis, and remote sensing techniques. Several parameters were collected from various sources in vector and raster GIS formats, and then, used within the GIS-based WLC analysis to select optimum solid waste disposal sites. Namely, urban areas, agricultural lands, access roads, surface aquifers, groundwater table, fault system, water wells, streams, and land slope were considered in this research. Also, the trend of urban expansion within the study area was monitored using the Landsat data of 1989, 1999, and 2009 to support the selection process of disposal sites. It is found that about 84% of the study area was within “most suitable” to “moderately suitable” classes for landfill sites, while the rest of the study area was within “poorly suitable” and “unsuitable” classes. Based on the analysis of Landsat satellite data the urban area was expanded of more than 240% during the last three decades, mainly toward south, and southwest, except the villages near the existing disposal site, where the trend was toward east and northeast. Finally, three sites were suggested as alternatives to the existing disposal site taking into the consideration the environmental, biophysical, and economical variables applied in the GIS-based WLC analysis.

Using Remote Sensing and GIS Techniques to Study Soil Degradation Processes in North Shaanxi Province,China

Satellite image data and thematic map data were used to provide comprehensive views of surface-bound conditions such as soil and vegetation degradation. The current work applies a computerized parametric methodology, developed by FAO, UNEP and UNESCO to assess and evaluate soil degradation at 1∶250 000 mapping scale. The study area is located in the arid and semi-arid zone of the northern part of Shaanxi Province in China, a region with considerable agricultural potential; Landsat TM images were utilized to provide recent data on land cover and use of the area. ARC/INFO and ArcView softwares were used to manage and manipulate thematic data, to process satellite images, and tabular data source. ER mapper software is utilized to derive the normalized difference vegetation index (ND VI) values while field data to estimate soil erodibility ( SE ) factor. A system is established for rating soil parameters, slope, climate factor and human factor activity. The rating values serve as inputs into a modified universal soil loss equation (USLE) to calculate the present state and risk for soil degradation processes, namely soil wind erosion. The produced maps and tabular data show the risk and the present status of different soil degradation processes. The study area, in general, is exposed to high risk of wind erosion and high hazards of water erosion. Several desertification maps were produced, which reflect the desertification types persisting in the study area. Wind erosion, water erosion, vegetation degradation, physical degradation and salinization are the basic desertification maps, and others are combinations of these basic maps. In terms of statistic analysis, 33.75 % of the total land area (120.330 0 ha) is considered as sand or sand dune, and not included in our analysis of desertification. About 29.41 % of the total land area has slight or moderate desertification and 37.465 % is facing severe desertification.

Urbanization and Quality of Urban Environment Using Remote Sensing and GIS Techniques in East Delhi-India

An explosive increase of urban population, practically in all major cities and towns, has the consequent strain on the existing system manifested in an environmental chaos. The phenomena of accelerated urbanisation is the main culprit, wherein besides bringing higher standard of living, it has also brought problems, as growth of dense and unplanned residential areas, environmental pollution, non-availability of services and amenities, solid waste etc. Remote sensing satellite data is suitable for urban land use mapping to get detail and up- to-date information for environmental management. Where as GIS helps in developing database system for urban information, which supports decision making process. Development of digital database on all aspects of land use and urban planning is the next crucial task for the future in which remote sensing based informa-tion is going to play a major role. In Delhi, rise in population and growth in economic activity has led to en-vironmental degradation. With this view an attempt has been made to study the quality of urban environment in the East district of Delhi, which is experiencing very high urban growth with 98.75% urban population in 2001. For this study Landsat ASTER (MSS) data of year 2001 (15 m Ground resolution), Guide map of the year 1982 and demographic and environmental data has been used. Eight parameters were selected, which affect the urban environmental quality, namely built-up area, open spaces, household density, occupancy ra-tio, population density, accessibility to roads, noise and smell affected area. The study shows that the quality of environment has been degraded when we compare 1982 and 2003 data. Most of the East district was in a better state of environment in 1982, but in 2003 things have been changed and now 50% area is in very good, fair and desirable condition. The public participation and involvement should be encouraged planning and decisions making for the improvement in better urban environmental quality.

Combined Remote Sensing and GIS Techniques for Studying the Large Roman Urban System Expansion during the Last Twenty Years

Several factors may contribute to on-going challenges for spatial planning and policy in megacities such as Rome, including rapid population shifts, poorly organized areas, and lack of data through which monitoring urban growth and land use change. This research was conducted to examine past and current effects of the urbanization process, occurred over the large Roman urban system, on the basis of multi-source and multi-temporal optical remote sensing (RS) data, collected between 1990 and 2013. These changes were then validated via Geographic Information System (GIS) techniques, in a particular procedure applied to urban land/agricultural transformations. The proposed approach, based on geo-statistical methods, was used to calculate the index of innovative space (AP Index), useful for the monitoring of the urban sprawl phenomenon. Strong evidence of urban expansion over the north-eastern quarter of the city, accompanied by environmental degradation and loss of biodiversity, is provided. Urban infill developments are expected to emerge in the south-eastern areas too, and these might increase urban pressure as well. In conclusion, RS and GIS technologies together with ancillary data can be used to assist decision makers in preparing future plans to find out appropriate solutions to urbanization encroachment.

Estimation and mapping of water erosion and soil loss:Application of Gavrilovic erosion potential model(EPM)using GIS and remote sensing in the Assif el mal Watershed,Western high Atlas

Water erosion is a serious problem that leads to soil degradation,loss,and the destruction of structures.Assessing the risk of erosion and determining the affected areas has become crucial in order to understand the main factors influencing its evolution and to minimize its impacts.This study focuses on evaluating the risk of erosion in the Assif el mal watershed,which is located in the High Atlas Mountains.The Erosion Potential Model(EPM)is used to estimate soil losses depending on various parameters such as lithology,hydrology,topography,and morphometry.Geographic information systems and remote sensing techniques are employed to map areas with high erosive potential and their relationship with the distribution of factors involved.Different digital elevation models are also used in this study to highlight the impact of data quality on the accuracy of the results.The findings reveal that approximately 59%of the total area in the Assif el mal basin has low to very low potential for soil losses,while 22%is moderately affected and 19.9%is at high to very high risk.It is therefore crucial to implement soil conservation measures to mitigate and prevent erosion risks.

INTEGRATED VEGETATION CLASSIFICATION AND MAPPINGUSING REMOTE SENSING AND GIS TECHNIQUES

NOAA-AVHRR data have been more and more used by scientists because of its short temporal resolution,large scope, inexpensive cost and broad wave bands. On macro and middle scale of vegetation remote sensing, NOAAAVHRR possesses an advantage when compared with other satellites. However, because NOAA-AVHRR also problem of low resolution, data distortion and geometrical distortion, in the area of application of NOAA-AVHRR in largescale vegetation - mapping, the accuracy of vegetation classification should be improved. This paper discuss the feasibilityof integrating the geographic data in GIS(Geographical Information System) and remotely sensed data in GIS. Under theenvironment of GIS, temperature, precipitation and elevation, which serve as main factors affecting vegetation growth,were processed by a mathematical model and qualified into geographic image under a certain grid system. The geographicimage were overlaid to the NOAA-AVHRR data which had been compressed and processed. In order to evaluate the usefulness of geographic data for vegetation classification, the area under study was digitally classified by two groups of interpreter: the proposed methodology using maximum likelihood classification assisted by the geographic database and a conventional maximum likelihood classification only. Both result were compared using Kappa statistics. The indices to both theproposed and the conventional digital classification methodology were 0. 668(yew good) and 0. 563(good), respetively.The geographic database rendered an improvement over the conventional digital classification. Furthermore, in this study,some problems related to multi-sources data integration are also discussed.

Application of Remote Sensing and GIS in Mineral Alteration Mapping and Lineament Extraction Case of Oudiane Elkharoub (Requibat Shield, Northern of Mauritania)

The integration of remotely sensed data allowed the successful characterization of the mineral alteration zones of the Oudiane Elkharoub area in the Northeastern part of Reguibat Shield using image transformation techniques. As both chemical and geochemical analyses showed significant Au, Ag, Cu, Pb, Mn, Cr, Ni, Th and Y anomalies, it’s very interesting to apply the remote sensing and GIS in mineral resources mapping. The remote sensing is a direct adjunct to the field, lithologic and structural mapping, and more recently, GIS has played an important role in the study of mineralization areas. The integration of several evidential maps highlighted the plausible areas with high concentrations of chlorite, epidote, kaolinite, calcite, alunite, hematite, illite and sulfur among other key mineral alterations that reflect the intensity of hydrothermal effects and the probable sites of ore bodies. The methodological approach integrates geological information acquired from Aster and Landsat 8 OLI/TIRS (Operational Land Imager/Thermal InfraRed Sensor) images and a multi-criteria GIS analysis. The superimposition of various lineament and hydrothermal alteration maps and the consideration of precious and base metal indicators allowed the zoning of sites likely to contain mineral concentrations. Remote sensing becomes an important tool for locating mineral deposits in its own right, when the primary and secondary processes of mineralization result in the formation of spectral anomalies. Reconnaissance lithological mapping is usually the first step of mineral resource mapping. This is complimented with structural mapping, as mineral deposits usually occur along or adjacent to geologic structures, and alteration mapping, as mineral deposits are commonly associated with hydrothermal alteration of the surrounding rocks. Ground truthing and laboratory studies including XRD analysis were utilized to verify the results.

Delineation of groundwater potential zones using remote sensing and Geographic Information Systems(GIS)in Kadaladi region,Southern India

The primary objective of this research is to delineate potential groundwater recharge zones in the Kadaladi taluk of Ramanathapuram,Tamil Nadu,India,using a combination of remote sensing and Geographic Information Systems(GIS)with the Analytical Hierarchical Process(AHP).Various factors such as geology,geomorphology,soil,drainage,density,lineament density,slope,rainfall were analyzed at a specific scale.Thematic layers were evaluated for quality and relevance using Saaty's scale,and then inte-grated using the weighted linear combination technique.The weights assigned to each layer and features were standardized using AHP and the Eigen vector technique,resulting in the final groundwater potential zone map.The AHP method was used to normalize the scores following the assignment of weights to each criterion or factor based on Saaty's 9-point scale.Pair-wise matrix analysis was utilized to calculate the geometric mean and normalized weight for various parameters.The groundwater recharge potential zone map was created by mathematically overlaying the normalized weighted layers.Thematic layers indicating major elements influencing groundwater occurrence and recharge were derived from satellite images.2 Results indicate that approximately 21.8 km of the total area exhibits high potential for groundwater recharge.Groundwater recharge is viable in areas with moderate slopes,particularly in the central and southeastern regions.

Spatio-Temporal Land Cover Analysis in Makhawan Watershed (M.P.), India through Remote Sensing and GIS Techniques

The present study makes an attempt to assess land use/land cover (LU/LC) changes at watershed level through remote sensing and GIS techniques, in Makhawan Watershed, Madhya Pradesh (India). The study involves multi-temporal satellite data of IRS-1D LISS III of 2001 and IRS-P6 LISS III of 2011, which have been analyzed visually. The study reveals that major LU/LC changes were due to the combined effects of many parameters, viz.;decline in average rainfall, more urbanization, sustainable agricultural activities and successful wasteland reclamation programmes. The major LU/LC changes noticed in the watershed decrease in uncultivated land (15.79%), wasteland whereas increases in open scrub (13.99%) and cultivated land. Changes in LU/LC categories are also compared with elevation which shows that most of the changes are associated with low lying areas (lower elevation ranges) except open scrub which shows changes in both low as well as high elevation ranges. Another notable change is the shrinkage of reservoir during 2001-2011 period which is linked to the decline in rainfall over the years.

Assessing and Predicting Changes in the Status of Gambari Forest Reserve, Nigeria Using Remote Sensing and GIS Techniques

Rapid population growth and increasing economic activities have resulted in unsustainable exploitation and rapid decline in the spatial extent of forest reserves in Nigeria. Studying land use dynamics of these forest reserves is essential for analysing various ecological and developmental consequences over time. Land use/land cover mapping, change detection and prediction are essential for decision-making and implementing appropriate policy responses relating to land uses. This paper aims at assessing and predicting changes in land use/land cover at Gambari forest reserve, Nigeria using remote sensing and GIS techniques. The study determined the magnitude, rate and dynamics of change in the spatial extent of the forest reserve between 1984 and 2014 using multi-temporal datasets (Landsat TM 1984 and 2000 and OLI/TIRS 2014). The imageries were classified using ArcGIS 10.0 version with support of ground truth data and Land use Change Modeller (LCM) and Markovian processes were employed to analyse the pattern and trend of change. Prediction of 2044 scenario carried out using neural network, which is a built-in module in the Idrisi. The study revealed dramatic decline in the extent of the forest reserve as both the plantation of exotic tree species (Tectona grandis and Gmelina) and the indigenous stands have been logged in several places for timber and to make way for cultivation of crops. In addition, pressures from other land uses like settlements have also led to increased non-forest uses particularly bare grounds. The study concluded that increasing loss of the indigenous forest and plantation would continue thus having implications for biodiversity conservation in the study area. There is the need for participation of different stakeholders and sectors to solve conflicting demands on limited forest resources and ensure ecosystem integrity.

The Use of GIS, Remote Sensing and Shannon’s Entropy Statistical Techniques to Analyze and Monitor the Spatial and Temporal Patterns of Urbanization and Sprawl in Zarqa City, Jordan

The aim of this study is to understand and quantify the urban growth and trend in Zarqa city during the period 1990 to 2014 and to produce land use and cover map for the studied area through the use of the GIS and remote sensing techniques with Shannon’s Entropy statistical method. For this purpose, three Landsat images were used for land use classification by using supervised maximum likelihood classification techniques to extract and assess the changes of urban lands. The results indicated that the urban areas in Zarqa city increased by 22.15% in the period from 1990 to 2005 and 14.86% from 2005 to 2014, with a rate of expansion of 0.96 and by 1.31 km2/ year for the two time periods respectively. The entropy value increased from 1.20 in the first period to 1.38 in the second, while the entropy value for the NE, NW, SE and SW zones showed high values, which confirmed that urban expansion and sprawling had existed in the past twenty four years in the study area. Urban expansion and sprawl cause different impacts on the natural, economic, and aesthetic aspects of the city which lead and guide government officials and planners to understand and monitor current growth and visualize future growth.

Estimation of Sediment Yield of Govindsagar Catchment, Lalitpur District, (U.P.), India, Using Remote Sensing and GIS Techniques

Soil erosion is a global phenomenon, which results in sedimentation and siltation of reservoirs of major rivers. Remote sensing data provide a synoptic view from which several surface parameters can be derived to assess the sedimentation yield in the reservoirs. Hence estimation of sediment yield has become one of the important tasks for planners, engineers and decision makers. The present study in Govindsagar catchment, Lalitpur District, Uttar Pradesh (India), has been carried out using IRS LISS III data to analyse land use/cover characteristics besides drainage basin characterstics. Subsequently, Sediment Yield Index (SYI) of Govindsagar catchment has been estimated using surface derivatives and morphometric parameters using empirical formulae. Integration of results obtained from satellite data and morphometric analysis suggests that the Govindsagar catchment has very low rate of sediment yield i.e. 0.07 ha·m/year indicating a gentle slope and sustainable land use practices in the catchment. Low sediment yield also suggests less erosion in the catchment areas and healthy land use/cover scenario.

Identification of Groundwater Potential Zones in Sri Lanka Using Arial Photography,Remote Sensing and GIS Techniques

Majority of the population of Sri Lanka does not have modern pipe-born water system especially in rural areas.They depend entirely on deep hand pump tube wells and shallow dug wells for their domestic water requirements.Most of the shallow dug wells in the dry zone of Sri Lanka go dry during the dry period. So construction of tube wells increasing very rapidly in the dry zone of Sri Lanka.Groundwater potential zone maps are the most essential tool for locating tube wells.Arial photographs,Geographical Information Systems(GIS) data and satellite images have

Integrating Remote Sensing and GIS Techniques with Conventional Methods to Assess and Characterize Surface and Groundwater Resources of Tendaho Graben, Ethiopia

The study focused on water resource assessment through utilization of remote sensing, which is a powerful technique for the collection of multi-temporal synoptic data sets. Geographic Information System (GIS) has been also used for turning large volumes of spatial data into useful information by integrating spatial data such as topography, geology, precipitation, land cover, satellite images etc. for joint analysis. In this study Remote sensing techniques have offered useful information on regional geology, geomorphology, hydrology, soils and land use. Using Landsat 7 ETM+ path 167, row 52 drainage conditions, land use/cover, drainage patterns, lineaments and geomorphology (relief, morphology) analysis and interpretation have been made, all of which have influences on the movement and occurrence of groundwater. The interpretation of satellite data in conjunction with sufficient ground truth has made it possible to identify and outline various ground features that serve as direct or indirect indicators of the occurrence of groundwater. Different image processing techniques have been deployed to extract specific information for required analyses. Spatial filtering for tectonic structures identification, False Color Composite for identification of lithology, drainage etc. have been deployed. Through the spatial integration, it is observed that tectonic structures have controlled surface and sub surface water availability of the area. The present works in general have focused on the role of remote sensing and GIS techniques in surface and groundwater resources assessment with limited application of conventional methods. Remote sensing has invaluable capability in groundwater and surface water assessment of an area like this Graben where there is accessibility problem and challenging hot climatic conditions which hinders ground investigations.

Identification of Artificial Recharge Sites in Manchi Basin, Eastern Rajasthan (India) Using Remote Sensing and GIS Techniques

The present study is an attempt to prepare a water resource development action plan for Manchi basin in Eastern Rajasthan (India) using remote sensing and GIS techniques. Satellite data have proven to be very useful for surface study, especially in the preparation of land use/land cover and geomorphological map. Morphometric parameters are analyzed to understand the basin characteristics and its influence on the water resources for instance bifurcation ratio indicates high surface run off and low recharge in SB-I, IV, V. Low drainage density ranges from 2.41 (SB-IV) to 2.99 (SB-V) km/km2, with an average of 2.72 km/km2 showing permeable strata, dense vegetation and low relief. Analysis of shape parameters i.e. elongation ratio and circularity ratio suggest that Manchi basin is elongated in shape. Whereas, slope, geology and geomorphological mapping is done to demarcate groundwater potential zones for future exploration in the study area. Slope is inversely proportional to infiltration. Therefore, sub-basin areas having gentle slope permits less runoff and more infiltration as in alluvial plains and vice versa where hills and ridges are present. The integrated study helps in designing suitable sites for constructing water harvesting structures. Check dams, percolation tanks and nala bund are proposed at 1st, 2nd or 3rd drainage orders at SB-I and SB-IV with ravenous land (open scrub), uncultivated land, open forest & exposed rock present. Nala bund & check dam are proposed at SB-II & SB-V whereas, at SB-III check dams & percolation tanks are proposed so as to conserve the natural resources present in the basin. Finally, the best feasible water harvesting structures have been proposed within the sub-basins area using remote sensing and GIS techniques.

Studying the Impact of Pollution from Wadi Gaza on the Mediterranean Sea Using GIS and Remote Sensing Techniques

Wadi Gaza is considered as one of the most important coastal wetlands located on the Eastern Mediterranean Basin. It is witnessing rapid degradation due to anthropogenic activities including but not limited to discharge of municipal sewage, dumping of solid wastes, rampant use of pesticides and illegal poaching. They form a river of untreated wastewater, more than 5 km long, before its discharge into the Mediterranean Sea. This study aims to perform an analytical study of Wadi Gaza and study its effects on the pollution of the seawater opposite to it using GIS and remote sensing techniques. The flow accumulation, the watershed and the stream orders inside and outside the Gaza Strip are determined based on a DEM which involves a radar terrestrial scanning of Palestine carried out by NASA’s Endeavor Space Shuttle. The area of the watershed inside Gaza is estimated to be equal to 58.792 km2. The Study also shows that the total amount of contaminated water that flows into the sea can be estimated to reach 146.5 mm3/year. The total area of coastal sea contamination approximately reaches 38.8 km2 and is oriented to the north direction along the coastal shore and its influence extends to Gaza seaport, 10 km apart from the Wadi.