Water Resources Assessment

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Water Resources Assessment. Main Resources Surface water Groundwater Unconventional Tools Flood routing/delineation models Runoff models GIS Finite element Finite difference Lumped parameters models. Q in. S. Q out. Surface Water. General Equation I(t) – O(t) = Δ S/ Δ t - PowerPoint PPT Presentation

Transcript of Water Resources Assessment

  • Water Resources AssessmentMain ResourcesSurface waterGroundwaterUnconventional ToolsFlood routing/delineation modelsRunoff modelsGISFinite element Finite differenceLumped parameters models

  • Surface WaterGeneral Equation

    I(t) O(t) = S/tOin InputsPrecipitationBase flowOin OutputsE/ETInfiltrationIntakes

  • System BoundariesReservoirBalance S/t=(P*Ares+Qin)-(E*Ares+Qout)Residence Time S/I(t)Watershed S/t=(P*A)-(ET*A+Qout)

  • GroundwaterDefinitionsSaturated Zone: VWater=VvoidsUnsaturated Zone: VWater < VvoidsMoisture Content: VWater < VtotalVoids/Pores: allow the flow of waterWater Table: surface where the water pressure in the pores equals ZeroPorosity: n = Vvoids / Vtotal (~0 - 0.7)Hydraulic conductivity [L/T]= represents how easily water can flow through formationGravel >50 m/dayCourse Sand: K = 30-50 m/dayFine sand: K = 10-30 m/daySilt: K = 1-10 m/dayClay: K < 1 m/day

  • GroundwaterDefinitionsFormations types with respect to water bearingAquifer = permeable layer that contains and transmits water in large quantitiesConfinedUnconfined Aquiclude = impermeable layer that may contain water but transmissivity is very lowAquitard = semi permeable layer that transmits water in the vertical direction onlyAquifuge = impermeable layer that neither contains nor transmits water

  • General Cross Section of Gaza Aquifer

  • GroundwaterDarcy

  • GroundwaterAverage pore velocity

    Problem: A tracer traveled 3 days and 6 hours between 2 wells that are 20 m apart. Water elevation difference between the wells is 0.5m, porosity n=0.15. Estimate v, q, K

  • Groundwater BalanceSs [1/L] = Specific Storage = volume of water that a unit volume of aquifer releases under a unit decline in hydraulic headS [dimensionless] = Storativity = volume of water that a unit surface area of aquifer releases under a unit decline in hydraulic head

  • Groundwater BalancePollutants transport mechanismsAdvectionDiffusionDispersionMechanical dispersion coefficient Diffusion coefficient

  • Average Nitrates Concentrations (PWA, 2005 Data)

  • Average Chlorides Concentrations (PWA, 2005 Data)

  • Average Groundwater Level (PWA, 2005 Data)

  • Soil Map

  • Built Up Areas

  • Agricultural Areas