Water Resources Assessment
date post
16-Jan-2016Category
Documents
view
48download
3
Embed Size (px)
description
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