Geotourism aims at the conservation of geodiversity and the promotion of sustainable tourism of geoheritage sites. It has recently gained significant attention worldwide. Geodiversity within the borders of Saudi Arabia provides great opportunity for geotourism. The volcanic province in the western region, locally known as “Harrat,” represents an element of geodiversity. Therefore, Harrat Al-Madinah, the northern part of “Harrat Rahat” which exemplifies the intracontinental monogenetic type of volcanicity, has been evaluated for geotourism potential. A multi-criteria assessment and Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis were employed. The criteria of quantitative assessment include scientific and intrinsic values, educational values, economical values, conservational values, and added values. Five geosites have been identified, evaluated, and compared: Al-Duaythah volcanos, Jebel Nuthaila, Jebel Quraithah, the historical volcano 1256 AD, and the lava field. The first three geosites gained the highest overall score, offering suitable assets of geotourism. Scores of individual assessment criteria were variable depending on scientific significance, degree of accessibility, proximity to touristic services, and level of conservation. The set of strongpoints highlighted by SWOT analysis were based on the geological importance and surface condition of volcanic elements of Harrat Al-Madinah as well as on the availability of essential facilities including road network and accommodation. SWOT analysis has indicated several opportunities related to the tendency of the Saudi government to promote touristic investment and demands for varying resources of national income guided by the 2030 vision. Nevertheless, some constrains have risen due to refraining from unfamiliar style of tourism, tourism competitiveness with the neighboring Gulf countries, and foreseen environmental impacts and hazards.

Omdurman area, located west of the River Nile and White Nile is witnessing rapid urban expansion and land use change. Several axial irrigation schemes have developed accelerating the demand for water supply. This indeed, will place more pressure over the available groundwater resources. In order to measure any change of groundwater quality it is necessary to initially evaluate the background condition. This contribution employs a GIS- based Groundwater Quality Index (GQI) which synthesizes different variable water quality data (e.g. Cl-, Na+ and SO42+) by indexing them numerically relative to the World Health Organization (WHO) standards in order evaluate the overall groundwater quality in the study area.The GQI computed for Omdurman area indicated that the water quality is generally high (mean GQI = 90 out of 100) with respect to the WHO standards. Spatially the groundwater quality of the study area increased from the central area in the northeastern direction and decrease in the southeastern direction. This result was interpreted in terms of general groundwater flow, the recharge zone, geology and soil composition. Drilling at close distances and over pumping specially in the central region might create local variations of groundwater flow resulting in mixing of waters of different qualities deteriorating the quality of water in previously safe zones. This is expected due to the low hydraulic gradient (< 0.001) characterizing some parts of the study area as well as the minimum recharge far from the River Nile and the White Nile.

Eleven-year (1987-1997) time series data of remotely sensed vegetation index (NDVI) and meteorological observations (temperature, precipitation, cloud cover and relative humidity) provided a powerful tool to illuminate the response of global terrestrial vegetation to short-and long-term climate variability. NDVI being a sensitive estimator of the amount of photosynthetic active radiation intercepted by the canopy has been treated as a proxy for above ground net primary production (ANPP). Analyses of trends, multiple regression and correlation analyses were employed. The main result indicates a considerable increase (0.7~1.9%/year) of monthly vegetation production in all ecosystems over the investigated period, allied with an analogous increase (0.9~15%/year) in precipitation. Additionally, several direct relationships were also observed on the intra- and inter-annual time scales suggesting that the increase and variation of ANPP in most biomes could be mainly linked to the corresponding increase and variation in precipitation. Overall, the four climate variables play a considerable role in the inter-annual variability of ANPP of global vegetation.

Realistic runoff estimates are crucial for accurate design of storm water drainage systems, particularly in developing urban catchments which are prone to overland flow and street inundation following extreme rain storms. Khartoum, capital of Sudan, as many cities of the developing countries, lacks proper storm water drainage system. Local government is however, spending efforts to plan and design several storm drains in attempt to mitigate the problem of urban flooding during rainy season. This paper aims to estimate surface runoff in order to design a proposed storm drain in west central Khartoum. Long-term rainfall intensity data was analyzed in order to produce Intensity-Duration-Frequency curves. The Rational model was used for runoff estimation, and Manning formula for storm drain design. Geographical information system was used to visualize surface and topographic data and to obtain catchment characteristics. The storm drain was sub-divided into five sectors and the maximum calculated peak runoff was 3.17m3/s based on rainfall intensity of 10-year return period. The proposed drain design was rectangular in shape with a maximum cross sectional area equal to 3.3m2 (1.65 x 2m). Challenges to planning sustainable stormwater structures in Khartoum City were attributed to climate variability, urban development and change in surface conditions.

The main objective of this study is to carry out regional geological mapping and gold prospecting in the poor savannah Northern Kordofan State, central Sudan. The selection of the study area was based on its favorable gold mineralization geological setting. Syntheses of the various forms of imagery, digital image processing, spectral analysis and office mapping were conducted before going into the field. Field observations, chemical analysis and petrographic investigations have all been integrated with the help of Geographic Information Systems (GIS) to come out with reliable interpretation that can be implemented in similar geologic setting and climatic conditions. A package of digital image processing techniques was applied to Landsat7 Enhanced Thematic Mapper Plus (ETM+) image in order to increase the visual interpretability of the various lithological units for the purpose of geological mapping and delineation of alteration zones, which represent possible target zones for gold mineralization. Different color composite images in addition to the result of image transformation (including Red Green Blue, RGB to Intensity Hue Saturation, IHS; Principal Component Analysis, PCA) were prepared to facilitate the delineation of the main rock groups. Several ratio images were prepared, combined together and displayed in RGB color composites. The outcome of the image processing is the discovery of many alteration and shear zones which trend north-northeast to south-southwest affecting most of the rock types. 139 chip samples were collected from the alteration and shear zones, which were delineated by remote sensing data interpretation and actual field work. They include samples from quartz veins and rock alteration zones which were analyzed by fire assay. All the collected samples proved to be gold-bearing. The Au values range from 0.1 to 84.9 g/ton. Artisanal mining activity in the study area coincided with the remotely sensed data interpretation results conducted in this work, i.e. during the field checkup artisanal miners were found in the places where anomalous signals appeared in the satellite image, thus reinforcing the reliability of the employed approach of remote sensing and GIS for gold prospecting in poor savannah zones.

Predicting the amount of surface runoff reaching crossing point of a watershed stream with a highway is critical for accurate design of safe hydraulic structures and flood protection. Sharqu ElNeil locality of Khartoum, Sudan, has been subject to repeated flash floods amplified by the presence of Alilafon Street, which runs in the NW-SE direction forming a terrace obstructing the natural flow of seasonal streams towards the Blue Nile River plain. Existing structures (culverts) are unable to pass stream water. They were either insufficient in terms of cross sectional area, ill-designed, or were displaced due to unplanned urbanization. Therefore, the (SCS)-curve number (CN) method developed by US Soil Conservation Service was used combined with geographical information systems (GIS) in order to estimate peak discharge reaching stream crossing points and to re-evaluate existing hydraulic structures. From hydrological modeling and field survey, eight catchments and crossing points were identified. Catchment area ranged between 13.4 and 42.1 km(2) while the CN value ranged between 80 and 90. Rainfall intensity was obtained from frequency analysis of 100-year rainfall data. It has ranged between 5.5 and 65 mm/h for the 10-year return period. Computed peak discharge values ranged between 15.6 and 47.2 m(3)/s. Hydraulic structures were designed for each crossing point based on Manning formula. One new culvert and amendments for five existing structures were proposed.

Rainfall-runoff modeling has become an essential element in water resources management including planning, hydraulic design and flood protection. This paper aims to estimate peak runoff in order to design hydraulic structures at Khor Shambat crossing with the Ring Road (Omdurman Sector). Geographical Information system (GIS) and Remote Sensing were employed to model catchment and drainage characteristics. Frequency analysis of 100-year rainfall data was performed and Intensity-Duration-Frequency (IDF) curves were construction based on Gumbel distribution. Peak runoff was computed using Rational model and contributing area method. The Manning formula was used to design hydraulic structures. The peak runoff for the catchment of Khor Shambat was found to be 43.2 and 45 m3/s for the return periods 10 and 25 year, respectively, obtained applying rainfall intensities from IDF curves and routing through different nodes according to contributing area method. The peak runoff values were used to compute appropriate hydraulic design (culvert cross section) at the crossing point following reasonable assumptions and solving and substituting different parameters in a set of equations. Three culverts were proposed at kilo 9, at kilo 8 and at kilo 9.3, with 33.5, 3.4 and 10.2 m2 trapezoidal cross sectional area, respectively, designed for the 25-year return period.

Runoff is one of the most significant hydrological properties that are used in many national works, for optimum design of reservoirs and for flood forecasting. The main objective of this study was to estimate surface runoff in Atbara area, North Sudan, using GIS. The curve number (CN) method of the soil conservation service (SCS) was employed. GIS was used to generate the hydrologic soil map and the land used/land cover map which were then intersected in order to generate CN value map. Runoff was then evaluated for the whole area using rainfall data according to the SCS - CN method. The CN values ranged between 0 and 100.The results has shown that maximum runoff values are encountered in the river Nile and river Atbara channels and in the southeastern part of the study area associated with the soil group (D) and it’s hydrological properties. This paper clearly illustrates that the combination of GIS with Soil Conservation Service-Curve number technique can be applied to generate the curve number map and runoff map for hydrological investigations and water resources management.

The use of microtremor data to estimate site effects is very common in the world, nowadays. In the present research, the recorded ambient noise in Atbara area was used to compute the H/V spectral ratio and then to evaluate the local site effect of the area. Atbara city is situated on the superficial deposits that are able to amplify the seismic waves. A number of 83 microtremor measurements were obtained at the ground surface in Atbara area, using short period stations (SARA SL07). The processing of the data has been done by recent software using Nakamura techniques. The obtained H/V spectral ratio results illustrated that the fundamental frequency value ranges from 0.72 to 3.3 Hz, while the amplification factor value ranges between 2.1 and 9.6. From these parameters a vulnerability index was calculated which ranges from 1.76 to 128, the fundamental frequency, amplification factor and vulnerability index models in two and three dimensions were obtained. The final results showed that weak points are occurring within the Nile silts and clayey cover in Atbara region.

El Nino Southern Oscillation (ENSO) influences extensive regions around the globe causing global weather changes and affecting both marine and land ecosystems. ENSO events are also frequently held responsible for much of the variation in carbon fixation by terrestrial biosphere pool. The timing and size of the response of eight global vegetation biomes to ENSO events between 1987 and 1997 were investigated employing monthly Normalized Difference Vegetation Index (NDVI), temperature and precipitation data and monthly anomalies of sea surface temperature in the tropical Pacific. Lagged correlation analyses were used to identify times when the relationship between vegetation condition and ENSO is most robust and standardized NDVI departures were computed to estimate the size of vegetation response to ENSO. Warm ENSO phases appear to have delayed (7~17 months) and protracted negative impacts on vegetation in all biomes related in most cases to a decrease in precipitation but rarely to an increase of temperature. This impact starts earlier in the tropical and subtropical regions but delays in the temperate and cold regions. Positive/negative impacts of warm/cold ENSO phases on global vegetation are instantaneous and brief. Interestingly, the result also indicates that ENSO has significant impacts on Boreal forests which were previously considered to have little or weak association with ENSO. Almost in all biomes, warm ENSO phases tend to result in below average NDVI while cold and neutral phases tend to result in above average NDVI with significant departures being more frequent during cold and neutral phases.

Land use/land cover analysis are becoming increasingly important as every decision making process requires complete description of the land surface. The main objective of this research is to qualitatively identify the land use/land cover of Atbara area, Sudan, based on Landsat ETM + data. The band ratio technique was applied in order to present unique information that is not available in single bands. The resultant image was supposed to highlight differences between various land use/land cover classes in the study area. Several band ratios were created and two band ratio sets were assigned to the RGB of the color composite where the combined result of band ratios has allowed a better discrimination of land use/Land cover features. Twenty five ground truthing points were collected from the study area to confirm the identification of these features. Clearly, the processed images were able to highlight water bodies, vegetations, urban area and land where the highest concentration of vegetation was observed mainly along the banks of the river Nile and river Atbara. 95% of the ground truthing points were found to coincide with the previously identified land surface features. This indeed, represents the first step towards performing a successful supervised classification and generating Land use/Land cover maps.

Digital Image processing and GIS applications have been successfully utilized as major tools in mapping and prospecting for gold mineralization in the arid area of Wadi Umm Beckol-Wadi Akasha, northern Sudan. Geological traverses and way points for geological observations and sampling were plotted in the digitally enhanced Landsat TM+ imagery pre-field and a preliminary geological map was prepared. Ground checks helped in the preparation of the final regional geological map at the scale of 1:50000. The main elements of geology were found to include high-grade gneisses; low-grade green schist island-arc assemblage of metasediments, metavolcanics and ophiolitic tectonic melanges. The layered sequences-mentioned above- are intruded by syn-orogenic, I-type and post-orogenic, A-type granites; and are separated by structural contacts. In this study, at least two styles of gold mineralization were identified. One style is the auriferous (gold-bearing) talcose schist within an ophiolitic tectonic melange in the extreme south of the study area. These rocks appear pale pink-brown and light green in the 7, 4, 2 and 7, 5, 4 colour composite images; respectively. Two similar linear talcose schists were easily identified in the processed images and were confirmed by ground checks. Also, highly silicified carbonate graphitic schists occur within the metasediments, which were suspected to be highly altered serpentinites. Samples analyzed by fire assay were found to be auriferous. Similar two additional bands were easily distinguished and mapped making use of their characteristic light greenish blue colour in the 7, 4, 2; and dark – light blue colour in the 7, 5 ,4 colour composites. Furthermore, auriferous, sheared and silicified metavolcanics were easily identified as they appear reddish brown in the 7, 4, 2; and pale green in the 7, 5, 4 colour composites. So, geological mapping and prospecting for certain styles of gold mineralization can be successfully achieved through remotely-sensed criteria in arid zones such as the study area, where there is no vegetational cover to interfere with the signals. Indeed, interpretations must be supported by field check and laboratory studies.

Knowledge of spatial and temporal variability in groundwater quality is necessary to validate and compliment aquifer vulnerability estimates that have become important elements for sound resources planning. Here, to evaluate vulnerability of the unconfined groundwater, we assessed intrinsic aquifer vulnerability of the alluvial Nasuno Basin of Tochigi Prefecture, Japan, using the DRASTIC model. We also used a groundwater quality index, which synthesizes different available water quality data to delineate spatial variability in the overall groundwater quality. Data are mapped spatially in GIS (Geographic Information System) and the results integrated to assess the pollution risk and degree of sustainability of water quality in the basin. Although the study area was characterized by high to very high aquifer vulnerability, the groundwater quality was generally good with only limited zones showing relatively lower groundwater quality: the vicinity of the Naka and Houki Rivers and the lower part of the basin. This information clearly reflects the greater role of anthropogenic impacts (agricultural and urban activities) on the groundwater quality of the area.

Assessing the quality of groundwater is important to ensure sustainable safe use of these resources. However, describing the overall water quality condition is difficult due to the spatial variability of multiple contaminants and the wide range of indicators (chemical, physical and biological) that could be measured. This contribution proposes a GIS-based groundwater quality index (GQI) which synthesizes different available water quality data (e.g., Cl−, Na+, Ca2+) by indexing them numerically relative to the World Health Organization (WHO) standards. Also, introduces an objective procedure to select the optimum parameters to compute the GQI, incorporates the aspect of temporal variation to address the degree of water use sustainability and tests the sensitivity of the proposed model. The GQI indicated that the groundwater quality in the Nasuno basin, Tochigi Prefecture, Japan, is generally high (GQI <90). It has also displayed the natural (depth to groundwater table, geomorphologic structures) and/or anthropogenic (land-use and population density) controls over the spatial variability of groundwater quality in the basin. Temporally, groundwater quality is more variable in the upper and lower parts of the basin (variation, V, 15–30%) compared to the middle part (V, <15%) probably attributed to the seasonality of precipitation and irrigation of rice. In the lower southeastern part of the Nasuno basin and the vicinity of the Naka and Houki rivers the sustainable use of groundwater is constrained by the relatively low and variable groundwater quality. The model sensitivity analysis indicated that parameters which reflect relatively lower water quality (high mean rank value) and those of significant spatial variability imply larger impacts on the GQI and must be carefully and accurately mapped. Optimum index factor technique allows the selection of the best combination of parameters dictating the variability of groundwater quality and enables an objective and fair representation of the overall groundwater quality.

Vulnerability assessment to delineate areas that are more susceptible to contamination from anthropogenic sources has become an important element for sensible resource management and land use planning. This contribution aims at estimating aquifer vulnerability by applying the DRASTIC model as well as utilizing sensitivity analyses to evaluate the relative importance of the model parameters for aquifer vulnerability in Kakamigahara Heights, Gifu Prefecture central Japan. An additional objective is to demonstrate the combined use of the DRASTIC and geographical information system (GIS) as an effective method for groundwater pollution risk assessment. The DRASTIC model uses seven environmental parameters (Depth to water, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone, and hydraulic Conductivity) to characterize the hydrogeological setting and evaluate aquifer vulnerability. The western part of the Kakamigahara aquifer was dominated by "High" vulnerability classes while the eastern part was characterized by "Moderate" vulnerability classes. The elevated north-eastern part of the study area displayed "Low" aquifer vulnerability. The integrated vulnerability map shows the high risk imposed on the eastern part of the Kakamigahara aquifer due to the high pollution potential of intensive vegetable cultivation. The more vulnerable western part of the aquifer is, however, under a lower contamination risk. In Kakamigahara Heights, land use seems to be a better predictor of groundwater contamination by nitrate. Net recharge parameter inflicted the largest impact on the intrinsic vulnerability of the aquifer followed by soil media, topography, vadose zone media, and hydraulic conductivity. Sensitivity analyses indicated that the removal of net recharge, soil media and topography causes large variation in vulnerability index. Moreover, net recharge and hydraulic conductivity were found to be more effective in assessing aquifer vulnerability than assumed by the DRASTIC model. The GIS technique has provided efficient environment for analyses and high capabilities of handling large spatial data.