1. Water Resources Assessment Main Resources – Surface water – Groundwater – Unconventional Tools – Flood routing/delineation models – Runoff models – GIS – Finite element – Finite difference – Lumped parameters models

2. Surface Water General Equation I(t) – O(t) = ΔS/Δt O in Inputs – Precipitation – Base flow O in Outputs – E/ET – Infiltration – Intakes Q in Q out S

3. System Boundaries Reservoir – Balance ΔS/Δt=(P*A res +Q in )-(E*A res +Q out ) – Residence Time S/I(t) Watershed ΔS/Δt=(P*A)-(ET*A+Q out )

4. Groundwater Definitions – Saturated Zone: V Water =V voids – Unsaturated Zone: V Water < V voids – Moisture Content: V Water < V total – Voids/Pores: allow the flow of water – Water Table: surface where the water pressure in the pores equals Zero – Porosity: n = V voids / V total (~0 - 0.7) – Hydraulic conductivity [L/T]= represents how easily water can flow through formation Gravel >50 m/day Course Sand: K = 30-50 m/day Fine sand: K = 10-30 m/day Silt: K = 1-10 m/day Clay: K < 1 m/day

5. Groundwater Definitions – Formations types with respect to water bearing Aquifer = permeable layer that contains and transmits water in large quantities – Confined – Unconfined Aquiclude = impermeable layer that may contain water but transmissivity is very low Aquitard = semi permeable layer that transmits water in the vertical direction only Aquifuge = impermeable layer that neither contains nor transmits water

6. General Cross Section of Gaza Aquifer calcareous sandstone, unconsolidated sands Eocene chalks and limestone Clay marls, marine shales, and claystones

7. Groundwater – Darcy Intrinsic permeability

8. Groundwater – Average 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

9. Groundwater Balance S s [1/L] = Specific Storage = volume of water that a unit volume of aquifer releases under a unit decline in hydraulic head S [dimensionless] = Storativity = volume of water that a unit surface area of aquifer releases under a unit decline in hydraulic head

10. Groundwater Balance Pollutants transport mechanisms – Advection – Diffusion – Dispersion Mechanical dispersion coefficientDiffusion coefficient

11. Average Nitrates Concentrations (PWA, 2005 Data)

12. Average Chlorides Concentrations (PWA, 2005 Data)

13. Average Groundwater Level (PWA, 2005 Data)

14. Soil Map

15. Built Up Areas

16. Agricultural Areas