• Energy Research

The Bayech basin is located in southwestern Tunisia, a highly prone region to flooding risks. The Bayech basin is characterized by wadis that adopt a wide, sometimes ill-defined bed, often intersected by low-lying areas, resulting in a semi-endoreismo, greatly disrupting the flow regimes. The Bayech basin drains the slopes of the Nementchas and Tebessa mountains in Algeria, collecting water from the Medjen Bel Abbes plain in its middle course before crossing the Gafsa djebls chain at the Gafsa gap. In this basin, flooding is generally caused by high-intensity storms and is often relatively limited in extent. The slope shape and soil type can promote rapid surface runoff during intense rainfall. Therefore, the purpose of creating a web application, labeled ClimInonda, is to respond to a critical need of readily available information on climatic, environmental, and land use data collected in this basin and its morphometric characteristics using recent methods. The application consists of three essential components: the front-end, back-end, and database. The front-end focuses on the user interface, allowing users to interact with the application’s features. It communicates with the back-end through Hypertext Transfer Protocol requests for data processing and retrieval. The back-end handles the server-side operations, processes requests, and provides responses by retrieving data from the database. The database stores and manages the application’s data, ensuring integrity and efficient access. This modular architecture ensures a user-friendly interface, seamless data processing, and reliable data storage. Visualizations can include different types of data, such as satellite imagery, weather data, and terrain data, and can be displayed using various techniques, such as heat maps, contour maps, and 3D models, by providing easy-to-understand visualizations. ClimInonda is an application developed to expand upon existing platforms by providing a suite of exploratory data analysis features, including the ability to calculate the total precipitation depth recorded for any period, interpolate the annual recurrence interval for rainfall events, etc. A simple evaluation of the platform was performed to assess the usefulness and user satisfaction of the tool by professional users, and positive feedback was received. There is clear evidence that ClimInonda would provide the necessary basis for informed decision making by stakeholders and development agencies in arid and semi-arid Tunisia.

Flash floods are a significant threat to arid and semi-arid regions, causing considerable loss of life and damage, including roads, bridges, check dams and dikes, reservoir filling, and mudslides in populated areas as well as agricultural fields. Flood risk is a complex process linked to numerous morphological, pedological, geological, anthropic, and climatic factors. In arid environments such as where Bayech basin is located in southwestern Tunisia, the hydrometric data are insufficient due to the absence of measuring points. Using the hybrid fuzzy Analytical Hierarchy Process (F-AHP) and the frequency ratio statistical methods, this study aims to map flooding risks in an ungauged basin that is extremely prone to flooding. Data related to soil texture, slope, land use, altitude, rainfall, drainage density, and distance from the river were used in the risk analysis. The obtained flood risk maps from both F-AHP and FR models were validated on the basis of the Receiver Operating Characteristic (ROC), the Area Under the Curve (AUC), and the inventory map. Results revealed that areas of high and very high susceptibility to flooding are mainly located in the downstream part of the basin, where the town of Gafsa is located. Other upstream sites are also at risk. In this basin, slope is predominantly behind runoff accumulation, whereas soil type plays a major role in amplifying waterproofing and therefore overflow. The results derived from both methods clearly demonstrate a viable and efficient assessment in flood-prone areas. The F-AHP and FR methods have ROC values of 95% and 97%, respectively. Considering these results in the decision-making process, these outputs would enable the implementation of the necessary measures to mitigate flood risk impacts ensure sustainable development along with an effective management in Tunisian arid environments, for the well-being of local communities at risk.

Les évaluations des services écosystémiques et des pertes de fonctions des paysages de zones humides (c.-à-d. les zones humides et leurs bassins hydrologiques) souffrent de lacunes dans les connaissances concernant les impacts des changements hydroclimatiques en cours. Cette étude étudie les changements hydroclimatiques au cours de la période 1976-2015 dans 25 zones humides réparties dans les zones climatiques tropicales, arides, tempérées et froides du monde. Les résultats montrent que les paysages de zones humides ont été soumis à des changements de précipitations (P) et de température (T) cohérents avec les changements moyens sur la superficie terrestre du monde. Cependant, les paysages humides arides et froids ont connu des augmentations de T plus élevées que leur zone climatique respective. En outre, le P moyen a diminué dans les paysages humides arides et froids, contrairement au P des zones climatiques arides et froides, ce qui suggère que ces paysages humides sont situés dans des régions où les pressions climatiques sont élevées. Pour la plupart des paysages humides avec des données de ruissellement (R) disponibles, les diminutions étaient plus importantes dans R que dans P, ce qui a été attribué à l'aggravation des impacts du changement climatique par des pertes d'évapotranspiration accrues, par exemple causées par des changements d'affectation des terres. Las evaluaciones de las pérdidas de servicios y funciones de los ecosistemas de los paisajes húmedos (es decir, los humedales y sus cuencas hidrológicas) adolecen de lagunas de conocimiento con respecto a los impactos del cambio hidroclimático en curso. Este estudio investiga los cambios hidroclimáticos durante 1976-2015 en 25 paisajes húmedos distribuidos en las zonas de clima tropical, árido, templado y frío del mundo. Los resultados muestran que los paisajes húmedos estuvieron sujetos a cambios de precipitación (P) y temperatura (T) consistentes con los cambios medios en la superficie terrestre del mundo. Sin embargo, los paisajes húmedos áridos y fríos experimentaron mayores aumentos de T que su respectiva zona climática. Asimismo, el P medio disminuyó en los paisajes húmedos áridos y fríos, contrariamente al P de las zonas de clima árido y frío, lo que sugiere que estos paisajes húmedos se encuentran en regiones de presiones climáticas elevadas. Para la mayoría de los paisajes húmedos con datos de escorrentía disponibles (R), las disminuciones fueron mayores en R que en P, lo que se atribuyó al agravamiento de los impactos del cambio climático por mayores pérdidas de evapotranspiración, por ejemplo, causadas por cambios en el uso de la tierra. Assessments of ecosystem service and function losses of wetlandscapes (i.e., wetlands and their hydrological catchments) suffer from knowledge gaps regarding impacts of ongoing hydro-climatic change. This study investigates hydro-climatic changes during 1976-2015 in 25 wetlandscapes distributed across the world's tropical, arid, temperate and cold climate zones. Results show that the wetlandscapes were subject to precipitation (P) and temperature (T) changes consistent with mean changes over the world's land area. However, arid and cold wetlandscapes experienced higher T increases than their respective climate zone. Also, average P decreased in arid and cold wetlandscapes, contrarily to P of arid and cold climate zones, suggesting that these wetlandscapes are located in regions of elevated climate pressures. For most wetlandscapes with available runoff (R) data, the decreases were larger in R than in P, which was attributed to aggravation of climate change impacts by enhanced evapotranspiration losses, e.g. caused by land-use changes. وتعاني تقييمات خدمة النظام الإيكولوجي وفقدان وظائف الأراضي الرطبة (أي الأراضي الرطبة ومستجمعاتها الهيدرولوجية) من فجوات معرفية فيما يتعلق بآثار التغير المائي المناخي المستمر. تبحث هذه الدراسة في التغيرات المناخية المائية خلال الفترة 1976-2015 في 25 من المناظر الطبيعية الرطبة الموزعة عبر المناطق المناخية الاستوائية والجافة والمعتدلة والباردة في العالم. تظهر النتائج أن المناظر الطبيعية للأراضي الرطبة كانت عرضة لتغيرات هطول الأمطار (P) ودرجة الحرارة (T) بما يتفق مع متوسط التغيرات في مساحة اليابسة في العالم. ومع ذلك، شهدت المناظر الرطبة القاحلة والباردة زيادات T أعلى من منطقة المناخ الخاصة بها. كما انخفض متوسط P في المناظر الطبيعية الرطبة القاحلة والباردة، على عكس P في المناطق المناخية القاحلة والباردة، مما يشير إلى أن هذه المناظر الطبيعية الرطبة تقع في مناطق ذات ضغوط مناخية مرتفعة. بالنسبة لمعظم الأراضي الرطبة التي تحتوي على بيانات الجريان السطحي (R) المتاحة، كانت الانخفاضات أكبر في R منها في P، والتي تعزى إلى تفاقم تأثيرات تغير المناخ بسبب خسائر التبخر والنتح المعززة، على سبيل المثال الناجمة عن تغيرات استخدام الأراضي.