Цифровой репозиторий ГГМ РАН
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listelement.badge.dso-typeЭлемент, MORPHOLOGICAL CHARACTERISTICS AND MEDIUM-TERM EVOLUTION OF THE BEACHES BETWEEN CEUTA AND CABO NEGRO (MOROCCO)(2007) Anfuso G.; Martínez del pozo J.A.; Nachite D.; Benavente J.; Macias A.This work presents the results of a combined study on the beach morphology and the evolution at short- and medium-term of the littoral between Ceuta and Cabo Negro (Morocco). It is an interesting sector showing a great increase of human occupation and coastal structures. The monitoring program allowed for the reconstruction of the beach morphological behavior and the seasonal changes. The studied beaches presented reflective profiles recording little seasonality, with the most notable morphological changes being strictly related to storms. Surf Similarity and Surf Scaling parameters highlighted the existence of intermediate and reflective beach states, characterized by plunging breakers. Aerial photographs and a satellite image have been geo-referenced and elaborated with GIS tools to reconstruct the short- and medium-term evolution of the littoral and the sediment transport pathways. The littoral showed important erosion at short- and medium-term related to a negative sedimentary budget because of offshore transport. Sand accumulation was recorded close to the main ports, i.e., Marina Smir and Marina Kabila. These port structures constituted impermeable, fixed limits, which divided the studied area into littoral cells. Other free, transit limits were also observed.listelement.badge.dso-typeЭлемент, MONITORING LAND SUBSIDENCE IN SEMARANG, INDONESIA(2007) Marfai M.A.; King L.Semarang is one of the biggest cities in Indonesia and nowadays suffering from extended land subsidence, which is due to groundwater withdrawal, to natural consolidation of alluvium soil and to the load of constructions. Land subsidence causes damages to infrastructure, buildings, and results in tides moving into low-lying areas. Up to the present, there has been no comprehensive information about the land subsidence and its monitoring in Semarang. This paper examines digital elevation model (DEM) and benchmark data in Geographic Information System (GIS) raster operation for the monitoring of the land subsidence in Semarang. This method will predict and quantify the extent of subsidence in future years. The future land subsidence prediction is generated from the expected future DEM in GIS environment using ILWIS package. The procedure is useful especially in areas with scarce data. The resulting maps designate the area of land subsidence that increases rapidly and it is predicted that in 2020, an area of 27.5ha will be situated 1.5–2.0m below sea level. This calculation is based on the assumption that the rate of land subsidence is linear and no action is taken to protect the area from subsidence.listelement.badge.dso-typeЭлемент, ADSORPTION CAPACITY AND MINERALOGICAL AND PHYSICO-CHEMICAL CHARACTERISTICS OF SHUWAYMIYAH PALYGORSKITE (OMAN)(2007) Al-Futaisi A.; Jamrah A.; Al-Rawas A.; Al-Hanai S.In this paper, Shuwaymiyah palygorskite in the Sultanate of Oman has been characterized mineralogically by X-ray diffraction (XRD) and electron microscopy, chemically by oxide compositions, structural formulae, and cation exchange capacity (CEC), and physically by specific surface area and adsorption isotherms. Batch adsorption studies were performed to evaluate the adsorption performance of methylene blue (MB) basic dye on the local clay mineral. The quantitative XRD analysis indicates that the purity of some selected samples of palygorskite clay is very high (about 70% of the clay minerals are palygorskite and 30% kaolinite). The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images clearly support this conclusion. The adsorption equilibrium revealed that Shuwaymiyah palygorskite clay can uptake up to 51mg of MB per 1g mass of clay. MB adsorption is best fitted by Langmuir isotherm, and a pseudo-second-order kinetic model can be efficiently used to predict the kinetic of adsorption of MB by the palygorskite. The results obtained from these laboratory-scale adsorption tests indicate the promising adsorption capability of the Omani palygorskite.listelement.badge.dso-typeЭлемент, ESTIMATING GROUNDWATER RECHARGE INDUCED BY ENGINEERING SYSTEMS IN A SEMIARID AREA (SOUTHEASTERN SPAIN)(2007) Martín-Rosales W.; Gisbert J.; Pulido-Bosch A.; Vallejos A.; Fernández-Cortés A.The scarcity of water resources in semiarid regions is usually accompanied by brief periods of quite intense precipitation that can generate potentially catastrophic floods. In such regions, the use of runoff water for aquifer recharge can contribute to both flooding prevention and effective management of water resources. This paper presents the results of a study undertaken in southeastern Spain focusing on the recharge induced by a number of engineering structures (check dams) and gravel pits. The current network of check dams consists of 107dams, of which 64 are located over permeable substrates and so we can induce recharge of the storm runoff retained therein. The hydrological model was performed using the curve number method (CN) of the Service for the Conservation of Soils, utilizing code HEC-HMS. Results indicate that the proportion of runoff infiltrated through the check dams varies from 3% to more than 50%, according to the effective volume of water dammed and the substrate. In addition, hydrological modelling was carried out in a subbasin taking advantage of the presence of one of a number of gravel pits. The gravel pits are situated in the apical sectors of alluvial fans that overlie hydrogeological units that are widely overexploited, and so they are well positioned for use for artificial recharge. In this case, we conclude that a pit is capable of retaining and infiltrating the combined runoff volumes for various return periods (5, 25, 50, and 100years). Furthermore, the simulation carried out suggests that the recharge processes in these environments are intimately linked to episodic storm events. The incorporation of hydrogeological criteria in the design and construction of check dams could therefore be very useful for the optimum management of water resources in semiarid zones.listelement.badge.dso-typeЭлемент, ARSENIC-CONTAMINATED GROUNDWATER FROM PARTS OF DAMODAR FAN-DELTA AND WEST OF BHAGIRATHI RIVER, WEST BENGAL, INDIA: INFLUENCE OF FLUVIAL GEOMORPHOLOGY AND QUATERNARY MORPHOSTRATIGRAPHY(2007) Acharyya S.K.; Shah B.A.Arsenic contamination in groundwater affecting West Bengal (India) and Bangladesh is a serious environmental problem. Contamination is extensive in the low-lying areas of Bhagirathi–Ganga delta, located mainly to the east of the Bhagirathi River. A few isolated As-contaminated areas occur west of the Bhagirathi River and over the lower parts of the Damodar river fan-delta. The Damodar being a Peninsular Indian river, the arsenic problem is not restricted to Himalayan rivers alone. Arsenic contamination in the Bengal Delta is confined to the Holocene Younger Delta Plain and the alluvium that was deposited around 10,000–7,000years bp, under combined influence of the Holocene sea-level rise and rapid erosion in the Himalaya. Further, contaminated areas are often located close to distribution of abandoned or existing channels, swamps, which are areas of surface water and biomass accumulation. Extensive extraction of groundwater mainly from shallow aquifers cause recharge from nearby surface water bodies. Infiltration of recharge water enriched in dissolved organic matter derived either from recently accumulated biomass and/or from sediment organic matter enhanced reductive dissolution of hydrated iron oxide that are present mainly as sediment grain coatings in the aquifers enhancing release of sorbed arsenic to groundwater.