排序方式： 共有17条查询结果，搜索用时 46 毫秒
1.
Ben Ameur W Ben Hassine S Eljarrat E El Megdiche Y Trabelsi S Hammami B Barceló D Driss MR 《Marine environmental research》2011,72(5):258-264
Concentrations of ten polybrominated diphenyl ethers (PBDEs) and eight methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) collected from the Bizerte Lagoon and the Mediterranean Sea were investigated. To the best of our knowledge, this is the first report of these compounds in marine fishes from Tunisia. The PBDE mean concentrations in fish from Bizerte Lagoon were 45.3 and 96.2 ng g(-1) lw respectively in mullet and sea bass, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea were 7.80 and 27.9 ng g(-1) lw respectively. MeO-PBDE concentrations in mullet and sea bass from Bizerte Lagoon ranged from 6.46 to 286 ng g(-1) lw and from 49.4 to 798 ng g(-1) lw respectively, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea ranged from 190 to 401 ng g(-1) lw and from 353 to 578 ng g(-1) lw respectively. The total PBDEs and total MeO-PBDEs concentration in fish from Bizerte Lagoon were similar or slightly lower than those reported for other species from other locations around the world. 相似文献
2.
Assessment of soil erosion risk using SWAT model 总被引：3，自引：2，他引：1
Manel Mosbahi Sihem Benabdallah Mohamed Rached Boussema 《Arabian Journal of Geosciences》2013,6(10):4011-4019
Soil erosion is one of the most serious land degradation problems and the primary environmental issue in Mediterranean regions. Estimation of soil erosion loss in these regions is often difficult due to the complex interplay of many factors such as climate, land uses, topography, and human activities. The purpose of this study is to apply the Soil and Water Assessment Tool (SWAT) model to predict surface runoff generation patterns and soil erosion hazard and to prioritize most degraded sub-catchment in order to adopt the appropriate management intervention. The study area is the Sarrath river catchment (1,491 km2), north of Tunisia. Based on the estimated soil loss rates, the catchment was divided into four priority categories for conservation intervention. Results showed that a larger part of the watershed (90 %) fell under low and moderate soil erosion risk and only 10 % of the watershed was vulnerable to soil erosion with an estimated sediment loss exceeding 10 t?ha?1?year?1. Results indicated that spatial differences in erosion rates within the Sarrath catchment are mainly caused by differences in land cover type and gradient slope. Application of the SWAT model demonstrated that the model provides a useful tool to predict surface runoff and soil erosion hazard and can successfully be used for prioritization of vulnerable areas over semi-arid catchments. 相似文献
3.
Abstract Agricultural use and related water erosion may lead to significant changes in the sedimentological and hydrological characteristics of watersheds, and therefore negative consequences for rural development. This research aimed to put present-day soil erosion of the important Mejerda catchment into a historical context. The catchment of Wadi Mejerda in northern Tunisia has experienced soil erosion due to weather and human impacts for thousands of years. We used historical texts and results from archaeological research that go back to 1000 BC, as well as data collected during the last century. Soil erosion from different types of agricultural landscape management was analysed together with information on the soils' production potential, the hydrographic network and flood frequency. The results showed that water erosion has increased the hydrographic network by 65 km and increased the deltaic plain by as much as 15 km2/century. However, soil productivity has decreased significantly. Moreover, due to in channel sedimentation and river choking, the number of flooding occurrences has multiplied over the last century. Finally, it is shown that water erosion follows a specific cycle of degradation throughout the watershed. These findings should be considered for better water and soil management in the context of semi-arid areas. Editor Z.W. Kundzewicz Citation Jebari, S., Berndtsson, R., Lebdi, F., and Bahri, A., 2012. Historical aspects of soil erosion in the Mejerda catchment. Hydrological Sciences Journal, 57 (5), 901–912. 相似文献
4.
Haykel Sellami Isabelle La Jeunesse Sihem Benabdallah Marnik Vanclooster 《水文科学杂志》2013,58(8):1635-1657
AbstractThe SWAT model was tested to simulate the streamflow of two small Mediterranean catchments (the Vène and the Pallas) in southern France. Model calibration and prediction uncertainty were assessed simultaneously by using three different techniques (SUFI-2, GLUE and ParaSol). Initially, a sensitivity analysis was conducted using the LH-OAT method. Subsequent sensitive parameter calibration and SWAT prediction uncertainty were analysed by considering, firstly, deterministic discharge data (assuming no uncertainty in discharge data) and secondly, uncertainty in discharge data through the development of a methodology that accounts explicitly for error in the rating curve (the stage?discharge relationship). To efficiently compare the different uncertainty methods and the effect of the uncertainty of the rating curve on model prediction uncertainty, common criteria were set for the likelihood function, the threshold value and the number of simulations. The results show that model prediction uncertainty is not only case-study specific, but also depends on the selected uncertainty analysis technique. It was also found that the 95% model prediction uncertainty interval is wider and more successful at encompassing the observations when uncertainty in the discharge data is considered explicitly. The latter source of uncertainty adds additional uncertainty to the total model prediction uncertainty.
Editor D. Koutsoyiannis; Associate editor D. GertenCitation Sellami, H., La Jeunesse, I., Benabdallah, S., and Vanclooster, M., 2013. Parameter and rating curve uncertainty propagation analysis of the SWAT model for two small Mediterranean watersheds. Hydrological Sciences Journal, 58 (8), 1635?1657. 相似文献
5.
Mehdi A. Guemache Djamel Machane Hamoud Beldjoudi Sofiane Gharbi Leila Djadia Sihem Benahmed Hayet Ymmel 《Natural Hazards》2010,54(2):273-288
On March 20, 2006, an earthquake (M
w = 5.3; SED) struck the mountainous region of the Babors chain (Wilaya of Bejaia, northeast Algeria). The seismic epicenter
was located near the Kherrata village. This earthquake was felt on a large area of the northeastern part of Algeria. It reached
an intensity of VII (EMS scale) at the Laalam village, situated at about 20 km northeast of Kherrata. Here, many old and recent
houses were damaged or collapsed totally, four people died and 68 were injured. Field investigations revealed that these casualties
were caused by a landslide triggered by the earthquake. Many fissures were visible on ground throughout the site. They were
generated by both sliding and settling phenomena. The Laalam site is prone to landslide, as revealed by some evidences on
old instabilities. This is due to two main factors: local geomorphology and geology. These factors intervene synchronously
for reducing the slope instability at the Laalam village. The March 20, 2006 Kherrata earthquake was the trigger that released
the Laalam landslide. 相似文献
6.
Sandro Rinaldi Sihem Louati Hocine Bendjoudi Ghislain de Marsily 《Hydrogeology Journal》2014,22(4):943-956
Industrially sourced dense non-aqueous phase liquids (DNAPLs) contaminated an alluvial aquifer in France decades ago. The location(s) and nature of the pollution source zone(s) were unknown, and the dissolved concentrations of volatile organic compounds in the monitoring wells varied greatly with time. The aquifer was in hydraulic equilibrium with an artificial canal whose water level was highly variable (up to 5 m). These variations propagated into the aquifer, causing changes in the groundwater flow direction; a transient numerical model of flow and solute transport showed that they correlate with the concentration variations because the changes in the flow direction resulted in the contaminant plume shifting. The transient hydrogeological numerical model was built, taking into account solvent biodegradation with first-order chain, since biodegradation has a significant influence on the pollutant concentration evolution. The model parameterization confirms the position of the source zones among the potential troughs in the bedrock where DNAPLs could have accumulated. The groundwater model was successfully calibrated to reproduce the observed concentration variations over several years and allowed a rapid validation of the hypotheses on the functioning of the polluted system. 相似文献
7.
Mehdi A. Guemache Jean-Luc Chatelain Djamel Machane Sihem Benahmed Leila Djadia 《Journal of African Earth Sciences》2011,59(4-5):349-358
The goal of this paper is to document causes of the failure of stabilization measures undertaken for stabilizing a complex landslide threatening the Sidi Rached viaduct in Constantine, Algeria. Since the first instabilities, documented in 1910 during its construction, significant disturbances have been regularly observed on its eastern part and reinforcements carried out were only temporarily effective. Observed disturbances are inherently related to the fact that the eastern abutment and the three subsequent piers are built on unstable Maastrichtian marls whereas the remainder of the viaduct rests on stable Turonian limestone. The five main factors controlling the activation of the failure process are reviewed: (1) geomorphology, (2) geology, (3) human activities, (4) climate, and (5) seismicity. Data interpretation of two inclinometer surveys carried out close to the eastern abutment shows that the unstable mass moves westward, towards the Rhumel gorges. The main slip surface is located in the Maastrichtian schistose marl, at a depth ranging from about 8 m (west) to about 30 m (east). This translational slide is associated with a settling phenomenon due to the petrophysical properties of the unstable marl. 相似文献
8.
9.
10.
Abstract Soil erosion vulnerability and extreme rainfall characteristics over the Mediterranean semi-arid region of Tunisia are crucial input for estimation of siltation rate in artificial reservoirs. A comprehensive high-resolution database on erosive rainfall, together with siltation records for 28 small reservoirs, were analysed for this region, the Tunisian Dorsal (the easternmost part of the Atlas Mountains). The general life-span of these reservoirs is only about 14 years. Depending on the soil degradation in the different catchments, the corresponding reservoirs display a wide range of soil erosion rates. The average soil loss was 14.5 t ha?1 year?1 but some catchments display values of up to 36.4 t ha?1 year?1. The maximum 15-min duration rainfall intensity was used to determine the spatial distribution of rainfall erosivity. The northwestern parts of the Tunisian Dorsal display the most extreme rainfall erosivity. Spatial erosion patterns are to some extent similar; however, they vary greatly according to their location in the “soil degradation cycle”. This cycle determines the soil particle delivery potential of the catchment. In general, the northwestern parts of the Dorsal display modest soil erosion patterns due to the already severely degraded soil structure. Here, the soil surface is often the original bedrock. However, the greatest soil erosion occurs in the mid-eastern parts of the Dorsal, which represents the “degradation front”. The latter corresponds to the area with highest erosion, which is continuously progressing westward in the Dorsal. The large variation between the erosive rainfall events and the annual soil loss rates was explained by two important factors. The first relates to the soil degradation cycle. The second factor corresponds to the degradation front with the highest soil loss rates. At present this front is located at 300 m altitude and appears to be moving along an 80-km westward path starting from the east coast. A better understanding of the above can be used to better manage soils and soil covers in the Tunisian Dorsal area and, eventually, to decrease the soil erosion and reservoir siltation risk. Citation Jebari, S., Berndtsson, R., Bahri, A. & Boufaroua, M. (2010) Spatial soil loss risk and reservoir siltation in semi-arid Tunisia. Hydrol. Sci. J. 55(1), 121–137. 相似文献