Infiltration During Wadi Runoff A Modeling Tool for Improving Indirect Groundwater Recharge Assessment

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1 Faculty of Environmental Sciences, Institute of Hydrology and Meteorology, Chair of Hydrology Andy Philipp and Jens Grundmann Technische Universität Dresden, Chair of Hydrology Infiltration During Wadi Runoff A Modeling Tool for Improving Indirect Groundwater Recharge Assessment ICWRER 2013, Koblenz, Germany, June 6, 2013

2 Contents 01 Ephemeral River Flow and Transmission Losses 02 Concept of an Integrated Modeling System 03 Applications for Oman 04 Outlook Photo courtesy of David O. Rankin A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 2

3 01 Ephemeral River Flow and Transmission Losses Groundwater is often the only source of freshwater in arid areas The quantification of groundwater recharge is of paramount interest for water resources management Ephemeral river flow often features significant in-stream infiltration, referred to as transmission losses or indirect groundwater recharge Effects of transmission losses on flood flow in a semi-arid catchment (Walnut Gulch, Arizona). Data from Renard and Keppel (1966). A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 3

4 02 Concept of an Integrated Modeling System Groundwater recharge processes in an ephemeral channel under the influence of a recharge dam (e.g., as in Oman s Al Batinah coastal plain region). A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 4

5 02 Concept of an Integrated Modeling System An envisaged model therefore should Regard the governing, highly variable hydrodynamics Include transmission losses ( coupling!) Include dam operation and dam evaporation Circumvent numerical issues and singularity problems when modeling advancing free-boundary flow over an initially dry channel bed under weakening process dynamics A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 5

6 02 Concept of an Integrated Modeling System Components of the proposed wadi flow and dam simulation model. A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 6

7 02 Concept of an Integrated Modeling System Special focus: free-boundary problem of potentially weakly advancing flow (semi-)analytical zero-inertia model of Philipp et al. (2010) Assumptions (Nonprismatic) channel geometry approximated by power functions Only valid for non-zero (but weak) advance conditions Iterative solution procedure for the ZI model. A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 7

8 03 Applications for Oman The study area in Northern Oman, Al Batinah Region. A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 8

9 03 Applications for Oman Model calibration (roughness coefficient and infiltration parameters) for the neighboring catchment of Bani Kharus (with a series of gauges). A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 9

10 03 Applications for Oman Modeling results for Wadi Ma awil (06/06/07 event, caused by cyclone Gonu). Only stage recorder data available for validation. A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 10

11 03 Applications for Oman Spatiotemporal information on transmission losses below the recharge dam as potential upper boundary condition for groundwater modeling; Gonu event. A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 11

12 03 Applications for Oman Total event-related volumetric water balance (MCM); Gonu event. A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 12

13 03 Applications for Oman Advance and recession trajectories below Ma awil Dam; Gonu event. A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 13

14 04 Outlook Robust and accurate process-oriented modeling tool Performs well under weak-advance conditions and for initially dry channels beds (free lower boundary numerically stable) Further needs Better data (event-related for a series of gauges, channel morphology, observations of maximum extents of flow domain) Including (spatially and temporally) uncertain process parameters Inclusion of changing wadi morphology Sediment flow interactions Assessment of surface processes not addressed (i.e., re-evaporation) A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 14

15 Thanks For Your Attention! References Haimerl, G. & Strobl, T. (Ed.) Groundwater Recharge in Wadi Channels Downstream of Dams Technische Universität München, Institute of Hydraulic Engineering and Water Resources, Technische Universität München, Institut für Wasserwesen, 2004 Lerner, D. N.; Issar, A. S. & Simmers, I. Groundwater Recharge: A Guide to Understanding and Estimating Natural Recharge A. A. Balkema Publishers, Rotterdam, 1990 Philipp, A.; Schmitz, G. H. & Liedl, R. Analytical Model of Surge Flow in Nonprismatic Permeable Channels and Its Application in Arid Regions Journal of Hydraulic Engineering, 2010, 136, Philipp, A. & Grundmann, J. An Integrated Modeling System for Flash Flood Routing in Ephemeral Rivers Under the Influence of Groundwater Recharge Dams (accepted) Journal of Hydraulic Engineering, 2013 Renard, K. G. & Keppel, R. V. Hydrographs of ephemeral streams in the Southwest Journal of the Hydraulics Division of the ASCE, 1966, 92, de Vries, J. J. & Simmers, I. Groundwater recharge: an overview of processes and challenges Hydrogeology Journal, 2002, 10, 5-17 A. Philipp and J. Grundmann: Infiltration During Wadi Runoff Slide 15