SACM - United Kingdom
Permanent URI for this collectionhttps://drepo.sdl.edu.sa/handle/20.500.14154/9667
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Item Restricted Hydrochemical assessment of an urban groundwater-fed wetland at Sweet Briar Marsh(University of East Anglia, 2024) BinTani, Sharifah Ahmed; Hiscock, Kevinتتعمق هذه الأطروحة بعمق في النظام البيئي المعقد لمستنقع سويت براير، بهدف فهم العوامل العديدة التي تؤثر على جودة المياه. ستكشف الأطروحة عن التفاعلات والتأثيرات المعقدة التي تشكل التوازن الدقيق للمستنقعات من خلال فحص شامل لدرجة الحموضة والأكسجين المذاب والتوصيل ودرجة الحرارة ومستويات المغذيات. يسلط التحقيق الضوء على أن الجريان الزراعي والتوسع الحضري والأنشطة الصناعية تلعب دورًا مهمًا في رفع مستويات النترات والفوسفات، ويرجع ذلك أساسًا إلى الاستخدام المكثف للأسمدة وممارسات إدارة الثروة الحيوانية غير الكافية. تؤدي مستويات المغذيات المرتفعة هذه إلى تلوث المغذيات، مما يزيد من خطر التغذية الزائدة، حيث تحفز المغذيات الزائدة ازدهار الطحالب الضارة وتدهور جودة المياه. تم اقتراح استراتيجيات مختلفة لإدارة المياه لمكافحة هذه التحديات الملحة، بما في ذلك إدارة المغذيات الدقيقة وتدابير مكافحة التلوث. وتؤكد الدراسة على الحاجة الماسة إلى خطط إدارة مصممة خصيصًا والرصد المستمر لحماية الأراضي الرطبة. ويساهم هذا البحث في المعرفة الأوسع بممارسات إدارة الأراضي الرطبة الفعّالة من خلال توفير رؤى متعمقة من الملاحظات الميدانية، مع التأكيد على أهمية مواجهة قضايا جودة المياه المحلية.21 0Item Restricted GIS-Based Modeling of Shallow Groundwater Potential in Arid Regions under changing Climate and Future Water Demands: a case study of Al-Madinah, Saudi Arabia.(University of York, 2024-06-14) Alharbi, Ohood; McClean, Colin; Sakai, MarcoInvestigating water resources in arid regions is essential for managing water scarcity's unique challenges in these environments. GIS and remote sensing approaches have been applied here to model and analyse three main aspects: mapping potential groundwater zones, assessing climate change impacts, and examining future water needs under socio-economic scenarios. A fuzzy-frequency ratio model and a logistic regression model successfully delineated the potential groundwater zones. An ensemble of models performed well (Best model AUC = 0.943). Soil type was the most important factor in driving both models. The spatial distribution of very high potential groundwater areas in Al-Madinah is primarily compatible with volcanic lava areas with Lithosols and Calcic Yermosols soils. Assessing climate change under IPCC RCPs scenarios (2021-2100, RCP4.5 and RCP8.5) revealed that the temperature and Reference Evapotranspiration (ET0) rate of Al-Madinah is expected to continue to increase although rainfall may also increase by around 18.74% or 22.81 mm (2081-2100, RCP8.5) compared to 1970-2018. Such an increase might not have a pronounced effect on enhancing groundwater availability due to raising temperature (2°C) and ET0 (359.70 mm) with a higher probability of drought events indicated by the Standardised Precipitation Evapotranspiration Index (SPEI). Increases with higher water accumulation opportunities are predicted at 2081-2100 (RCP8.5). However, changes in potential groundwater zones using the Topographic Wetness Index (TWI) weighted by Rainfall are expected to show a small quantitative increase with the greatest addition of suitable potential zones also estimated for 2081-2100 under RCP8.5 (logistic regression = 19296km²) Analysing water needs in Al-Madinah city under the Impact of Population, Affluence, and Technology (IPAT) model confirmed that population was the most important factor in explaining water consumption trends. Water demand is projected to increase by up to 28% under IPCC_ SSP scenarios. These findings should aid in developing water resources management strategies and sustainable decision-making.37 0Item Restricted DELINEATING GROUNDWATER POTENTIAL ZONES IN JAZAN REGION, SAUDI ARABIA: A GIS AND REMOTE SENSING APPROACH USING ANALYTIC HIERARCHY PROCESS(Saudi Digital Library, 2023-11-22) Aljehani, Naif; Tansey, KevinIn arid countries such as Saudi Arabia, groundwater is an essential source of fresh water. The Jazan region is one of the Saudi Arabian regions and has the highest population density in the country. This region relies on groundwater as a source of fresh water, and the demand for this source has increased by 11,000 m3/day over the past 13 years. To meet this demand, identifying groundwater potential zones (GWPZ) becomes crucial. This dissertation aims to delineate GWPZ in 94% of the Jazan region using remote sensing, GIS, and the analytic hierarchy process (AHP), and ten thematic layers were generated for this purpose. Notably, incorrect classification and ranking of vegetation and water spectral indices (e.g., NDVI, NDWI, and NDMI) and a spatial correlation between them and the LULC thematic layer were observed in recent published studies. To address this, two thematic layers, CVWI (a combination of these indices) and MLULC (CVWI merged with land use/ land cover), were suggested. Two methods, AHP and weighted overlay analysis, were conducted, resulting in two GWPZ maps that were validated against regional observation well data. Findings revealed that merging vegetation and water indices with land use/ land cover in a single thematic layer yielded a better performing model compared to using them separately in the overlay analysis. It was determined that 62% of the study area in the Jazan region is categorised as a high potential zone. This differed from earlier studies, which allocated more area to zones of very high potential.35 0