What happened when agricultural and urban growth outstripped the capacity of local rivers?

• A. Rivers became deeper
• B. Water quality improved
• C. Fish populations increased
• D. Water supply cannot meet demand

Answer: (D)

When human demand grows faster than what a river can provide, the river’s flow and available water fall short of what is needed. Withdrawals for irrigation and urban use remove water faster than it can be replenished, so downstream supply becomes insufficient to meet all needs. That leads to water shortages and a gap between demand and supply. The other ideas don’t fit this situation: rivers aren’t typically drawn deeper by higher withdrawals, water quality generally worsens with runoff and concentration of pollutants, and fish populations often decline with reduced flow and degraded water conditions.