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Erosion and Sedimentation Studies in the Wadi Al Arab Catchment/ Alternative Method Application and First Results in a Data Scarce Environment North Jordan –

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Erosion and Sedimentation Studies in the Wadi Al Arab Catchment/ Alternative Method Application and First Results in a Data Scarce Environment North Jordan – Erosion and sedimentation studies in the Wadi al Arab catchment/ Alternative method application and first results in a data scarce environment north Jordan – . Sabine Kraushaar1, Thomas Schumann2, Martin Weber3, Tino Rödiger1, Christian Siebert1, Hans-Jörg Vogel1,3 1 Helmholtz-Centre for Environmental Research - UFZ, Theodor-Lieser-Straße 4, 06120 Halle, contact: [email protected] 2 University of Leipzig, Institute for Geography, Johannisallee 19a, 04103 Leipzig 3 Martin-Luther-University-Halle-Wittenberg, Von-Seckendorff-Platz 3, 06120 Halle Why soil and erosion studies in Jordan? IMPORTANCE: The soil layer and its physical PROBLEM: Jordan has a quantitative and AIM: The SMART project (= Sustainable Management integrity is a key player to slow down runoff, qualitative water problem in combination with of Available Water Resources with Innovative safeguard infiltration, buffer and filter a growing demand by population increase Technologies) aims at developing an integrated water pollutants AND important for artificial recharge (2.3% in 2009, CIA 2009). resource management for the region. basins and hydrological models. Erosion Measurement Wadi Al-Arab Map: Mallast 2011 Common erosion measurement methods include model simulations and plot experiments. However, these methods need appropriate data input, are time limited, suffer from boundary conditions and depend on “the big event” to happen to get reasonable results (Montgomery 2008). This method compilation covers longer time periods AND includes all specific erosion processes: 1. Field measurement in the land units erosion was observed => To understand what happens in the landscape 2. Analysis of the sink – Wadi Al-Arab lake => To know what actually accumulates in the important water reservoir Research Area Catchment: 263,50km² Geology: Marl & Limestone 3. Chemical characterization of the sources Precipitation: 300 to 500mm => To connect lake sediments to the sediment sources and estimate their contribution In several field campaigns 4 main 1) Olive orchards 2) Agricultural Fields 3) Overgrazed natural slopes 4) Natural patchy vegetation sediment sources were identified on the basis of: - visible erosion features, like olive mounds, rills, gullies, and siltation - predominant landscape units 1) Field measurements Method Application Slope pre rain season M 1 650 ± 50 years M 2 74cm in 800 years 71cm M 3 1450 ± 150 years Slope post rain season OSL Dating of accumulated Sediments: 2 abandonned Roman cisterns used as historical Erosion pin fields: 3 fields (each 200m²) Recent sediment traps: 3 runoff Olive mound method (Vanwalleghem 2010) : 7 Olive orchards (each ~800m²) were measured. sediment traps. were installed. events were caught. Eroded volume averaged = 88,00 t/ha/year = 0,22 t/ha/year = 43,33 t/ha/year = 1,79 t/ha/year 2) Analysis of the sink - Wadi Al-Arab Lake 3) Chemical characterization of the sources The Wadi Al-Arab Dam Lake Canonical Discriminant Functions The sediment sources has a sedimentation rate of -20 -15 -10 -5 0 5 10 15 20 Group are chemically 67160m³. 6 6 centroids discriminable by 4 4 following elements: Agricultural The spatial concentrated 2 2 fields sedimentation is 3 times Pb TOC 0 0 higher close to the dam wall Ti Cu Function Function 2 -2 -2 Overgrazed Rb U and the outlet than expected. natural 40 137 -4 -4 slopes K Cs 234Th 226Ra This presumably constitutes -6 -6 Olives -20 -10 0 10 20 214Pb a threat to the life span of Function 1 the reservoir! Reclassified: 100% Cross Validated: 94,40 % In the final step a mixing model algorithm will be used to estimate the relative contributions of the individual sediment source to the lake Acknowledgments: Great thanks goes to Nico Herrmann and Stephan Schulz for their help and expertise in the field. Furthermore we would like to express our appreciation to Hussein Al-Shurieki, manager of the Dam, for logistic help and the German tax payer for substantially funding the research through the German Federal Ministry of Science and Education (BMBF), the IPSWat Program and the Helmholtz Impulse and Networking Fund through Helmholtz Interdisciplinary Graduate School for Environmental Research (HIGRADE). Vanwalleghem, T.; Laguna, A.; Giráldez, J.V.; Jiménez-Hornero, F. J. (2010): Applying a simple methodology to assess historical soil erosion in olive orchards. In: Geomorphology 114: 294-302. Montgomery, D. R. (2008): Dirt! The erosion of civilizations. 285S.: Los Angeles, London, University of California Press. .
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