water demands

1. Environmental Engineering I
CE 331

2. Overview
•Water Demand
•Hydrological Cycle
•Source of water

3. Water Demand
• Total annual volume in liters or million liters.
• Annual Average rate of draft in liters per day, (V/365).
• Average rate of draft in liters per day per person (liters per
capita day or lcpd), called per capita demand (q).
• Fluctuations in flows expressed in terms of % ratios of maximum
or minimum yearly, monthly, daily or hourly rates to their
corresponding average values.

4. Water Demand
• Domestic water demand
• Industrial water demand
• Institutional and Commercial water demand
• Demand for public use
• Fire demand

5. World Water Distribution

6. Hydrologic Cycle/Water Cycle
• Terrestrial Ecosystem
• Aquatic Ecosystem
• Flows of water
• Human Activities

7. Hydrologic Cycle

8. Water Cycle
• Evaporation: Conversion from liquid to vapor.
• Transpiration: Evaporation of water from leaves.
• Condensation: Conversion of vapor to liquid.
• Precipitation: Movement as rain, sleet, hail and snow.
• Infiltration: Movement into soil.
• Percolation: Downward flow through soil to aquifer.
• Runoff: Surface flow down slope to ocean, river or lake.

10. Rainwater Harvesting