Despite the vast areas with low population densities, the states in the region are among the most urbanized in the country in terms of the proportions of their populations in urban areas. Nevada is the most urban state in the country, for example, while Utah is the sixth. These urban and economic systems are in turn based on a rich mix of ecosystems including alpine mountain areas, deserts, forests, fertile valleys, riparian ecosystems, and coastal areas. All of these systems, human and natural, will potentially be effected by climate variability and change. This makes federal and state government agencies responsible for managing the lands very important stakeholders.
Water availability is among the top concerns in the region.
Rapid population growth has greatly expanded urban water demands and has increased impacts on other key resources including air quality. The region's water use exceeds sustainable supply, and the demand at current prices is growing rapidly. Surface water supplies are insufficient, and groundwater use in many areas exceeds groundwater recharge rates, leading to the lowering of aquifer levels, contamination, and subsidence. In many parts of the region, agriculture, livestock, urban centers, tourism, and recreation are already faced with extreme pressures from the limits of water supplies. Ecological systems are particularly stressed due to water extractions from natural systems, and recent court and legislative mandates have directed that water be returned to these ecosystems to restore past damage.