The negative externalities of flooding the Hetch Hetchy Valley include the destruction of a natural national treasure, loss of ancestral homes and cultural sites of Native Americans, harm to local businesses, disruption of irrigation and farming in the San Joaquin Valley, and damage to the river and surrounding ecosystems including wildlife disruption. These actions also set a controversial precedent by prioritizing a single city's needs over public land preservation and natural habitat conservation.
On the positive side, flooding Hetch Hetchy created a reservoir that provides a reliable source of pristine drinking water and hydroelectric power essential for San Francisco and the Bay Area. The dam offers renewable energy with low greenhouse gas emissions and water security in a region facing population growth and climate change. The reservoir water requires minimal filtration, reducing costs and environmental impact compared to other sources. It supports a large population's water and energy needs sustainably for decades.
Weighing these factors, whether the negative externalities outweigh the positive ones largely depends on values and priorities: ecological preservation, cultural heritage, and natural beauty versus essential urban water supply, clean renewable energy, and regional sustainability. From a utilitarian perspective, the positive externalities for millions of people requiring safe water and energy might outweigh the negatives. However, from an environmental preservation standpoint, the significant permanent damage to a unique ecosystem and heritage site poses a heavy cost that some argue is too high. The debate remains a classic conflict between conservation and utilitarian use of natural resources.
In conclusion, the question does not have a simple answer, but the negative externalities of flooding Hetch Hetchy are substantial and profound, affecting ecology, culture, and local communities, while the positive gains are centered on clean water and energy provision critical for urban sustainability. The decision reflects a fundamental societal trade-off between protecting unique natural landscapes and meeting human resource needs.
