Implicit flow routing on terrains with applications to surface networks and drainage structures

Flow-related structures on terrains are defined in terms of paths of steepest descent (or ascent). A steepest descent path on a polyhedral terrain T with n vertices can have T(n^2) complexity. The watershed of a point p --- the set of points on T whose paths of steepest descent reach p --- can have complexity T(n^3). We present a technique for tracing a collection of n paths of steepest descent on T implicitly in O(n logn) time. We then derive O(n log n) time algorithms for: (i) computing for each local minimum p of T the triangles contained in the watershed of p and (ii) computing the surface network graph of T. We also present an O(n^2) time algorithm that computes the watershed area for each local minimum of T

Regular Hierarchical Surface Models: A conceptual model of scale variation in a GIS and its application to hydrological geomorphometry

Environmental and geographical process models inevitably involve parameters that vary spatially. One example is hydrological modelling, where parameters derived from the shape of the ground such as flow direction and flow accumulation are used to describe the spatial complexity of drainage networks. One way of handling such parameters is by using a Digital Elevation Model (DEM), such modelling is the basis of the science of geomorphometry. A frequently ignored but inescapable challenge when modellers work with DEMs is the effect of scale and geometry on the model outputs. Many parameters vary with scale as much as they vary with position. Modelling variability with scale is necessary to simplify and generalise surfaces, and desirable to accurately reconcile model components that are measured at different scales. This thesis develops a surface model that is optimised to represent scale in environmental models. A Regular Hierarchical Surface Model (RHSM) is developed that employs a regular tessellation of space and scale that forms a self-similar regular hierarchy, and incorporates Level Of Detail (LOD) ideas from computer graphics. Following convention from systems science, the proposed model is described in its conceptual, mathematical, and computational forms. The RHSM development was informed by a categorisation of Geographical Information Science (GISc) surfaces within a cohesive framework of geometry, structure, interpolation, and data model. The positioning of the RHSM within this broader framework made it easier to adapt algorithms designed for other surface models to conform to the new model. The RHSM has an implicit data model that utilises a variation of Middleton and Sivaswamy (2001)’s intrinsically hierarchical Hexagonal Image Processing referencing system, which is here generalised for rectangular and triangular geometries. The RHSM provides a simple framework to form a pyramid of coarser values in a process characterised as a scaling function. In addition, variable density realisations of the hierarchical representation can be generated by defining an error value and decision rule to select the coarsest appropriate scale for a given region to satisfy the modeller’s intentions. The RHSM is assessed using adaptions of the geomorphometric algorithms flow direction and flow accumulation. The effects of scale and geometry on the anistropy and accuracy of model results are analysed on dispersive and concentrative cones, and Light Detection And Ranging (LiDAR) derived surfaces of the urban area of Dunedin, New Zealand. The RHSM modelling process revealed aspects of the algorithms not obvious within a single geometry, such as, the influence of node geometry on flow direction results, and a conceptual weakness of flow accumulation algorithms on dispersive surfaces that causes asymmetrical results. In addition, comparison of algorithm behaviour between geometries undermined the hypothesis that variance of cell cross section with direction is important for conversion of cell accumulations to point values. The ability to analyse algorithms for scale and geometry and adapt algorithms within a cohesive conceptual framework offers deeper insight into algorithm behaviour than previously achieved. The deconstruction of algorithms into geometry neutral forms and the application of scaling functions are important contributions to the understanding of spatial parameters within GISc

Flow computations on imprecise terrains

We study water flow computation on imprecise terrains. We consider two approaches to modeling flow on a terrain: one where water flows across the surface of a polyhedral terrain in the direction of steepest descent, and one where water only flows along the edges of a predefined graph, for example a grid or a triangulation. In both cases each vertex has an imprecise elevation, given by an interval of possible values, while its (x, y)-coordinates are fixed. For the first model, we show that the problem of deciding whether one vertex may be contained in the watershed of another is NP-hard. In contrast, for the second model we give a simple O(n log n) time algorithm to compute the minimal and the maximal watershed of a vertex, where n is the number of edges of the graph. On a grid model, we can compute the same in O(n) time.Peer ReviewedPostprint (published version

Morphologic characterization of urban watersheds and its use in quantifying hydrologic response

2009 Summer.Covers not scanned.Includes bibliographical references.Print version deaccessioned 2022.Current methods for hydrologic characterization of urban watersheds and analysis of the impacts of urbanization are primarily based on the description of imperviousness and how changes in this characteristic affect storage, infiltration, and runoff generation. The morphology of urban watersheds and the effects of urbanization on the structure of the drainage system have been much less studied. The overarching objectives of this study are to develop methodologies to characterize the morphology of urban drainage systems including the hillslopes, streets, pipes, and channels and to use this characterization to model the hydrologic response of the watershed. These objectives are accomplished through: (a) an exploration of potential applications of morphologic theories in the characterization of urban watersheds and the impacts of urbanization; (b) the development and testing of a methodology to generate urban terrains (i.e. a raster representation of the topography) in which the effects of conduits typically observed in urban areas are represented; and (c) the development and testing of a new rainfall-runoff model called the U-McIUH (Urban Morpho-climatic Instantaneous Unit Hydrograph). The model is based on the morpho-climatic instantaneous unit hydrograph theory, in which the hydrologic response is identified from the spatial structure of the watershed and the properties of the storm event. The morphologic approach adopted reveals significant impacts of urbanization on the internal structure of natural watersheds at a wide range of scales. This finding is relevant when building stormwater models intended to simulate and compare the pre- and post-development catchment response. The morphologic impacts should be incorporated into stormwater models through the redefinition of model parameters that characterize both the channelized and unchannelized portions of the catchment when the urbanized scenario is simulated. This research also shows the importance of incorporating artificial conduits into urban terrain for hydrologic modeling. A new method to incorporate the artificial conduits into the DEM based on the real elevation of these conduits proved to be superior to other previously available methods because it better represents the flow directions and flow paths. Finally, the new rainfall-runoff model developed in this study fills an existing gap in the field of distributed stormwater modeling. It provides a more thorough treatment of the flows in minor conduits and unchannelized portions of the watershed, which enhances the simulations of runoff accumulation that are traditionally used in conceptual models. The model is parsimonious and uses a simplification of kinematic wave routing that considers the dependence of the unit hydrograph on rainfall intensity and the effect of upstream contribution on the travel times without explicitly solving the flow equation at each cell for each time step. This simplification reduces the complexity of the model computations while still producing reasonable model performance

Flow Computations on Imprecise Terrains

We study the computation of the flow of water on imprecise terrains. We consider two approaches to modeling flow on a terrain: one where water flows across the surface of a polyhedral terrain in the direction of steepest descent, and one where water only flows along the edges of a predefined graph, for example a grid or a triangulation. In both cases each vertex has an imprecise elevation, given by an interval of possible values, while its (x,y)-coordinates are fixed. For the first model, we show that the problem of deciding whether one vertex may be contained in the watershed of another is NP-hard. In contrast, for the second model we give a simple O(n log n) time algorithm to compute the minimal and the maximal watershed of a vertex, where n is the number of edges of the graph. On a grid model, we can compute the same in O(n) time

Training of Crisis Mappers and Map Production from Multi-sensor Data: Vernazza Case Study (Cinque Terre National Park, Italy)

This aim of paper is to presents the development of a multidisciplinary project carried out by the cooperation between Politecnico di Torino and ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action). The goal of the project was the training in geospatial data acquiring and processing for students attending Architecture and Engineering Courses, in order to start up a team of "volunteer mappers". Indeed, the project is aimed to document the environmental and built heritage subject to disaster; the purpose is to improve the capabilities of the actors involved in the activities connected in geospatial data collection, integration and sharing. The proposed area for testing the training activities is the Cinque Terre National Park, registered in the World Heritage List since 1997. The area was affected by flood on the 25th of October 2011. According to other international experiences, the group is expected to be active after emergencies in order to upgrade maps, using data acquired by typical geomatic methods and techniques such as terrestrial and aerial Lidar, close-range and aerial photogrammetry, topographic and GNSS instruments etc.; or by non conventional systems and instruments such us UAV, mobile mapping etc. The ultimate goal is to implement a WebGIS platform to share all the data collected with local authorities and the Civil Protectio

Groundwater investigation and modeling - western desert of Iraq

The region of interest is part from Iraqi western desert covering an area about 100,000 km². Several of the large wadis such as Hauran, Amij, Ghadaf, Tubal and Ubaiydh traverse the entire region and discharge into the Euphrates River. The present study included the following hydrogeological investigations: Lineaments interpretation was done by using different data sets (SRTM 30 m and Landsat ETM 15m), within different algorithms. Some faults recognized by field survey match rather well with the automatically extracted lineaments with only a small difference between field data and re-mote sensed data. The groundwater flow directions (west to east) for three aquifers were determined by using different spatial interpolation algorithms. Due to the faults impact, the flow direction gets a slightly other direction when reaching the fault’s zone. Two pumping test were performed close to fault 2 in the unconfined aquifer Dammam using well no. 9 and 17. Results of pumping test and recovery were evaluated with the analytical model MLU for Windows. Well 17 shows a slightly higher transmissivity (0.1048 m²/min) in compari-son to well 9 (T= 0.0832 m²/min). This supports the assumption of a zone of unique elevated permeability between fault 1 and fault 2 because of the tectonic stress and the anticline structure. The catchment and watershed delineation was performed by means of four GIS packages utilizing three DTM´s: 90 m and 30 m SRTM (Shuttle Radar Topography Mission) and the ASTER 30 m. A thorough field survey and manual catchment delineation of the same area was available from Division 1944. Software used was Arc Hydrotools, TNTmips, River Tools and TecDEM. Ten 90 m SRTM and twelve 30 m ASTER files were merged by means of ArcGIS. The 30 m SRTM dataset of Iraq was supplied by courtesy of the US Army and the region of interest (ROI) was clipped from this DTM using ArcGIS. No additional steps were performed with both DTM data sets before using the mentioned software products to perform the catchment analysis. As a result the catchment calculations were significantly different for both 30 m and 90 m data and the different software products. The groundwater model implemented in Visual Modflow V.4.2 was built by 5 main layers repre-senting Dammam aquifer, first aquiclude, UmEr Duhmma aquifer, second aquiclude and the Tayarat aquifer. Averaged readings of groundwater head from 102 observation wells were used to calibrate the model. Calculated recharge average was 17.5 mm/year based on the water balance for ~30 years (1980-2008). A sensitivity analysis was performed by using different permeability and recharge values. However, the model showed a rather low sensitivity because the values of the standard error of the estimation were between 2.27 m and 3.56 m. Models with recharge less than 11.85 mm/year or more than 60 mm/year did not converge and thus failed to produce a result. Models with Kf values from 1.1-3 to 1.1-4 m/s for aquifers and from 1.1-7 to 1.1-8 m/s for aquicludes converged. Water budget is about 2.17*10¹⁰ m³/year; by irrigating the greenhouses this budget will cover only 1.75% of the total area. However, this value could be upgraded up to 8 – 9 % by utilizing the groundwater inflow from Saudi Arabia.:List of Content Page Dedication ………………………………..………………..2 Acknowledgment ………………………………..………………..3 List of contents …………………………………..……………..4 List of Figures ………..……………………………..….......…8 List of Tables ………..……………………………….…….…9 List of abbreviations ………..……………………………….………10 English Abstract ……………………………………….………..12 German Abstract ..………………...…………………….……….14 1 Introduction ………..……………………………….………16 1-1 Preface ………..……………………………….………16 1-2 Region of interest ………..……………………………….………16 1-3 Previous Studies ………..……………………………….………17 1-3-1 Local studies ………..……………………………….………17 1-3-1-1 Hydrogeological Studies ………..………………………….…….17 1-3-1-2 Remote Sensing Studies ………..………………………….…….18 1-3-2 Global studies …..……………………………….…….18 1-3-2-1 Groundwater flow and fracture zone ..………………………...19 1-3-2-2 Lineaments extraction ………..…………………………….….19 1-3-2-3 Watershed delineation ………..……………………….……….20 1-4 Importance of investigation area ……………..………………..…24 1-5 Motivation ………..……………………………….…….…24 1-6 Deliverables ………..……………………………….………24 1-7 Problems ………..……………………………….………26 2 Methodology ………..……………………………….………27 2-1 Literature review ………..……………………………….………27 2-2 Personal contact ………..……………………………….………27 2-3 Field work ………..……………………………….………27 2-4 Evaluation of geological data ………………………….………27 2-4-1 Geological cross section ….……..……………………….27 2-4-2 Fault system by means of remote sensing techniques …..………28 2-5 Climate and Meteorology..…..………………………………....……28 2-5-1 Meteorological data ………..……………………………….………28 2-5-2 Aridity index ………..……………………………….………28 2-5-3 Groundwater recharge ………..…………………………….….29 2-5-4 Vegetation index ………..……………………………….………29 2-5-5 Actual evaporation ………..……………………………….………30 2-5-6 Soil moisture ………..……………………………….………32 2-5-7 Runoff ………..……………………………….………32 2-6 Hydrogeology ………..……………………………….………34 2-6-1 Pumping test ………..……………………………….………34 2-6-2 Groundwater flow ………..……………………………….………34 2-6-3 Wadi catchment delineation ……………………………….…34 2-6-3-1 Dataset ………..……………………………….………34 2-6-3-2 Approaches ………..……………………………….………34 2-6-3-3 Software packages ………..……………………………….………35 2-6-4 PC options ………..……………………………….………39 2-6-5 Groundwater Model ………..……………………………….………39 2-6-5-1 Conceptual model ………..……………………………….………40 2-6-5-2 Input ………..……………………………….………41 2-6-5-3 Properties ………..……………………………….………41 2-6-5-4 Boundary conditions ………..……………………………….………41 2-6-5-5 Observation wells ………..……………………………….………42 2-6-5-6 Solver ………..……………………………….………42 2-6-5-7 Calibration ………..……………………………….………42 3 Geological setting ………..……………………………….………44 3-1 Preface ………..……………………………….………44 3-2 Tectonic and structure …………………………………………..…...44 3-3 Stratigraphy ………..……………………………….………46 3-3-1 Tayarat formation ………..……………………………….………47 3-3-2 Umm Er Radhumma formation ………………………………....47 3-3-3 Dammam formation ………..……………………………….………48 3-3-4 Euphrates formation………..…………………………………………48 3-4 Topography and Ubaiydh Wadi …………………………………49 4 Climate and meteorology.…………………………………..………51 4-1 Preface ………..……………………………….………51 4-2 Precipitation ………..……………………………….………51 4-3 Temperature ………..……………………………….………52 4-4 Potential evaporation …………………………………………53 4-5 Relative humidity ………..……………………………….………54 4-6 Wind ………..……………………………….………55 4-7 Sunshine duration ………..……………………………….………56 5 Hydrogeology ………..……………………………….………57 5-1 Preface ………..……………………………….………57 5-2 Tayarat aquifer ………..……………………………….………57 5-2-1 Pressure conditions ………..……………………………….………57 5-2-2 Hydraulic characteristics …………………………………………57 5-2-3 Water quality ………..……………………………….………58 5-3 Um Er Radumma aquifer …………………………………………58 5-3-1 Pressure conditions ………..……………………………….………58 5-3-2 Hydraulic characteristics …………………………………………58 5-3-3 Water quality ………..……………………………….………59 5-4 Dammam aquifer ………..……………………………….………59 5-4-1 Pressure conditions ………..……………………………….………59 5-4-2 Hydraulic characteristics …………………………………………60 5-4-3 Water quality ………..……………………………….………60 6 Result and discussion …………………………………………61 6-1 Topographic contour map …………………………………………61 6-2 Geological cross section …………………………………………62 6-3 Lineaments evaluation …………………………………………65 6-4 Groundwater flow ………..……………………………….………66 6-5 Pumping test evaluation …………………………………………70 6-6 Catchment calculation …………………………………………72 6-7 Water balance and Recharge ……………………………….…76 6-8 Groundwater model ………..……………………………….………78 6.8.1 Model sensitivity ………..……………………………….………80 6.8.2 Groundwater management ……………………………….…83 7 Conclusion and recommendations …………………………………84 7.1 Conclusion ………..……………………………….…….…84 7.2 Recommendations ………..……………………………….…….…85 8 References ………..……………………………….………86 9 Appendixes ………..……………………………….………90 10 Field work Photos ………..……………………………….………115 11 Author CV. ………..……………………………….………116Das Untersuchungsgebiet umfasst eine Fläche von etwa 100.000 km² und ist Teil der westlichen irakischen Wüste. Einige der großen Wadis wie Hauran, Amij, Ghadaf, Tubal und Ubaiydh durchqueren die gesamte Region und entwässern in den Euphrat. Die vorliegende Arbeit umfasst folgende hydrogeologische Untersuchungen: Die Interpretation der Lineamente wurde anhand verschiedener Datensätze (SRTM 30 m und Landsat ETM 15 m) und unter Nutzung unterschiedlicher Algorithmen durchgeführt. Einige Störungen, welche während Feldmessungen identifiziert wurden, stimmen gut mit automatisch extrahierten Lineamenten überein, der Unterschied zwischen Feld- und Fernerkundungsdaten ist somit gering. Die Ermittlung der Grundwasserfließrichtungen (von West nach Ost) der drei Aquifere erfolgte unter Nutzung verschiedener Algorithmen zur räumlichen Interpolation. Es zeigte sich, dass die Störungen zu einer leichten Veränderung der Fließrichtung mit zunehmender Nähe zur Störungszone führen. Zwei Pumpversuche in den Brunnen 9 und 17 wurden nahe der Störung 2 im ungesättigten Aquifer Dammam durchgeführt. Die Auswertung der Ergebnisse der Pump- und Wiederanstiegsversuche erfolgte mittels des analytischen Modells MLU für Windows. Es zeigte sich, dass Brunnen 17 eine leicht höhere Transmissivität aufweist (T = 0,1048 m²/min) im Vergleich zu Brunnen 9 (T = 0,0832 m²/min). Dies unterstützt die Annahme der Existenz einer Zone erhöhter Permeabilität zwischen den Störungen 1 und 2, verursacht durch tektonischen Stress und die Antiklinalstruktur. Die Erfassung von Einzugsgebiet und Wasserscheiden erfolgte anhand von vier GIS-Paketen unter Nutzung von 3 DTM’s: 90 m und 30 m SRTM (Shuttle Radar Topography Mission) sowie ASTER 30 m. Genaue Daten aus einer Feldkampagne und eine manuelle Abgrenzung des Einzugsgebietes derselben Region standen zur Verfügung (Division 1944). Als Software kamen Arc Hydrotools, TNTmips, River Tools und TecDEM zum Einsatz. Zehn SRTM- (90 m) und zwölf ASTER-Files (30 m) wurden mittels ArcGIS vereinigt. Ein 30 m SRTM-Datensatz des Irak (bereitgestellt durch die US-Armee) diente als Grundlage für das Ausschneiden des Untersuchungsgebietes (ROI) mit Hilfe von ArcGIS. An beiden DTM Datensätzen wurden vor der Ermittlung des Einzugsgebietes mit den genannten Software-Produkten keine zusätzlichen Schritte durchgeführt. Als Resultat ergaben sich signifikante Unterschiede zwischen den 30 m und 90 m Datensätzen sowie der verschiedenen Software. Das in Visual Modflow V.4.2 implementierte Grundwassermodell wurde aus fünf Hauptschichten bestehend aus Dammam Aquifer, erster Stauer, UmEr Duhmma Aquifer, zweiter Stauer und Tayarat Aquifer aufgebaut. Durchschnittliche Werte der Grundwasserstände aus 102 Observationsbrunnen dienten der Kalibrierung des Modells. Die berechnete mittlere Grundwasserneubildung betrug 17,5 mm/a, basierend auf dem Wasserhaushalt der letzten 30 Jahre (1980-2008). Unter Einbeziehung verschiedener Werte für Permeabilität und Grundwasserneubildung wurde eine Sensitivitätsanalyse durchgeführt. Dabei ergab sich allerdings eine geringe Empfindlichkeit des Modells, resultierend aus einer Standardabweichung der Schätzung zwischen 2,27 m und 3,56 m. Modelle mit einer Grundwasserneubildung kleiner 11,85 mm/a und größer 60 mm/a zeigten keine Konvergenz und führten somit zu keinem Ergebnis. Modelle mit kf Werten zwischen 1.1-3 und 1.1-4 m/s für Aquifere und zwischen 1.1-7 und 1.1-8 m/s für Grundwasserstauer konvergierten. Die Grundwasserneubildung betrug etwa 2,17∙10¹⁰ m³/a, für die Bewässerung von Gewächshäusern deckt diese Summe nur 1,75% des gesamten Gebietes ab. Allerdings könnte dieser Wert durch die Nutzung des Grundwasserzuflusses aus Saudi Arabien auf 8 – 9% gesteigert werden.:List of Content Page Dedication ………………………………..………………..2 Acknowledgment ………………………………..………………..3 List of contents …………………………………..……………..4 List of Figures ………..……………………………..….......…8 List of Tables ………..……………………………….…….…9 List of abbreviations ………..……………………………….………10 English Abstract ……………………………………….………..12 German Abstract ..………………...…………………….……….14 1 Introduction ………..……………………………….………16 1-1 Preface ………..……………………………….………16 1-2 Region of interest ………..……………………………….………16 1-3 Previous Studies ………..……………………………….………17 1-3-1 Local studies ………..……………………………….………17 1-3-1-1 Hydrogeological Studies ………..………………………….…….17 1-3-1-2 Remote Sensing Studies ………..………………………….…….18 1-3-2 Global studies …..……………………………….…….18 1-3-2-1 Groundwater flow and fracture zone ..………………………...19 1-3-2-2 Lineaments extraction ………..…………………………….….19 1-3-2-3 Watershed delineation ………..……………………….……….20 1-4 Importance of investigation area ……………..………………..…24 1-5 Motivation ………..……………………………….…….…24 1-6 Deliverables ………..……………………………….………24 1-7 Problems ………..……………………………….………26 2 Methodology ………..……………………………….………27 2-1 Literature review ………..……………………………….………27 2-2 Personal contact ………..……………………………….………27 2-3 Field work ………..……………………………….………27 2-4 Evaluation of geological data ………………………….………27 2-4-1 Geological cross section ….……..……………………….27 2-4-2 Fault system by means of remote sensing techniques …..………28 2-5 Climate and Meteorology..…..………………………………....……28 2-5-1 Meteorological data ………..……………………………….………28 2-5-2 Aridity index ………..……………………………….………28 2-5-3 Groundwater recharge ………..…………………………….….29 2-5-4 Vegetation index ………..……………………………….………29 2-5-5 Actual evaporation ………..……………………………….………30 2-5-6 Soil moisture ………..……………………………….………32 2-5-7 Runoff ………..……………………………….………32 2-6 Hydrogeology ………..……………………………….………34 2-6-1 Pumping test ………..……………………………….………34 2-6-2 Groundwater flow ………..……………………………….………34 2-6-3 Wadi catchment delineation ……………………………….…34 2-6-3-1 Dataset ………..……………………………….………34 2-6-3-2 Approaches ………..……………………………….………34 2-6-3-3 Software packages ………..……………………………….………35 2-6-4 PC options ………..……………………………….………39 2-6-5 Groundwater Model ………..……………………………….………39 2-6-5-1 Conceptual model ………..……………………………….………40 2-6-5-2 Input ………..……………………………….………41 2-6-5-3 Properties ………..……………………………….………41 2-6-5-4 Boundary conditions ………..……………………………….………41 2-6-5-5 Observation wells ………..……………………………….………42 2-6-5-6 Solver ………..……………………………….………42 2-6-5-7 Calibration ………..……………………………….………42 3 Geological setting ………..……………………………….………44 3-1 Preface ………..……………………………….………44 3-2 Tectonic and structure …………………………………………..…...44 3-3 Stratigraphy ………..……………………………….………46 3-3-1 Tayarat formation ………..……………………………….………47 3-3-2 Umm Er Radhumma formation ………………………………....47 3-3-3 Dammam formation ………..……………………………….………48 3-3-4 Euphrates formation………..…………………………………………48 3-4 Topography and Ubaiydh Wadi …………………………………49 4 Climate and meteorology.…………………………………..………51 4-1 Preface ………..……………………………….………51 4-2 Precipitation ………..……………………………….………51 4-3 Temperature ………..……………………………….………52 4-4 Potential evaporation …………………………………………53 4-5 Relative humidity ………..……………………………….………54 4-6 Wind ………..……………………………….………55 4-7 Sunshine duration ………..……………………………….………56 5 Hydrogeology ………..……………………………….………57 5-1 Preface ………..……………………………….………57 5-2 Tayarat aquifer ………..……………………………….………57 5-2-1 Pressure conditions ………..……………………………….………57 5-2-2 Hydraulic characteristics …………………………………………57 5-2-3 Water quality ………..……………………………….………58 5-3 Um Er Radumma aquifer …………………………………………58 5-3-1 Pressure conditions ………..……………………………….………58 5-3-2 Hydraulic characteristics …………………………………………58 5-3-3 Water quality ………..……………………………….………59 5-4 Dammam aquifer ………..……………………………….………59 5-4-1 Pressure conditions ………..……………………………….………59 5-4-2 Hydraulic characteristics …………………………………………60 5-4-3 Water quality ………..……………………………….………60 6 Result and discussion …………………………………………61 6-1 Topographic contour map …………………………………………61 6-2 Geological cross section …………………………………………62 6-3 Lineaments evaluation …………………………………………65 6-4 Groundwater flow ………..……………………………….………66 6-5 Pumping test evaluation …………………………………………70 6-6 Catchment calculation …………………………………………72 6-7 Water balance and Recharge ……………………………….…76 6-8 Groundwater model ………..……………………………….………78 6.8.1 Model sensitivity ………..……………………………….………80 6.8.2 Groundwater management ……………………………….…83 7 Conclusion and recommendations …………………………………84 7.1 Conclusion ………..……………………………….…….…84 7.2 Recommendations ………..……………………………….…….…85 8 References ………..……………………………….………86 9 Appendixes ………..……………………………….………90 10 Field work Photos ………..……………………………….………115 11 Author CV. ………..……………………………….………11

Leveraging Crowdsourced Navigation Data In Roadway Pluvial Flash Flood Prediction

This dissertation develops and tests a new data-driven framework for short-term roadway pluvial flash flood (PFF) risk estimation at the scale of road segments using crowdsourced navigation data and a simplified physics-based PFF model. Pluvial flash flooding (PFF) is defined as localized floods caused by an overwhelmed natural or engineered drainage system. This study develops a data curation and computational framework for data collection, preprocessing, and modeling to estimate the risk of PFF at road-segment scales. A hybrid approach is also developed that couples a statistical model and a simplified physics-based simulation model in a machine learning (ML) model to rapidly predict the risk of roadway PFF using Waze alerts in real-time