1500 □ Groundwater Population 口 Surface water □ Total 250 1200 200 900 508 600 100 300 1950195519601965197019751980198519901995 Figure 16.5 Total withdrawals of fresh water increased from 1950 to 1980 largely because of expanded irri- gation systems and urban developments. After 1980, however, conservation measures reduced water usage even in the face of a growing population