Irrigation and Drainage Engineering Lecture (1)

Lecture (1) Irrigation and Drainage Engineering Clouds

Clouds

Hydrologic Cycle: P = Precipitation E = Evaporation T = Transpiration ET = Evapotranspiration GW= Groundwater I = Infiltration R

P

ET GW Moisture

P

ET

P T

T T

E R I

I

E

I

Unsaturated

Water Table

Saturated Groundwater (GW)

E R

E

Water Cycle for the Earth : Land 30 % Oceans = 70 % Land ET P 72 cm/yr. 41 cm runoff to oceans 31 cm Oceans 112 cm/yr + 31 ×

0.3 = 125 cm (E) ↑ 0.7

≅ ≅ 270 x 1012 m3/yr * Lakes and rivers Egypt share 55 x 109 ≅ 0.02% of the world fresh water

Irrigation : It is an artificial mean of water application to soil to ensure enough moisture essential for plant life

Drainage:

It is an artificial mean of removal of excess groundwater from the root zone

Water Budget: ET P

P ET

P + RI + GI = ET + Ro + Go. +ΔSm + ΔSg P = ET + ΔR + ΔG + ΔSm + ΔSg

Ro

R

I

River

Sm GI

Sg

Go

Rainfed Versus Irrigated Agriculture: Regions Humid Semi-Humid Semi-Arid Arid Desert

P (mm/yr) 1500-2000 1000-1500 500-1000 250-500 Less than 250

Irrigation Forrests Rainfed Supplementary Irrigation Irrigation

Drainage -----May be May be May be May be

Cultivated Versus Irrigated Areas: Country Egypt China France Japan USA

Cultivated Area (106 fed.) 8.1 275.0 77.0 14.5 300.0

Irrigated 7.8 13.0 6.0 8.0 30.0

Total Irrigation area in the world ≅ 500 x 106 feddans

% 96 47 8 55 10

Irrigation Process

Delivery System

Water

Source Traditional Surface Water Ground Water Non-Traditional Agr. Drainage Reuse Treated Wastewater Reuse Desalinization Fog Collection Cloud Seeding

Quality • Fresh • Saline

Canals Irrigation Str. Pump Stations

Field Irrigation Method

Surface Sprinkle

Irrigation Application

Drip

Amount (Depth) Frequency (Soil Inf. Rate and ET)