Colorado is a headwaters state, with the majority of the state’s rivers beginning high in the Rocky Mountains as snowmelt. One of the benefits of living in a state that relies primarily on surface water is that, unlike groundwater, surface water is a renewable water source.
Aurora receives 95% of its water from surface water sources, with the remaining 5% from deep aquifer groundwater wells. Replenished each year through snowmelt, Aurora’s water supply is transported 180 miles from its source through a complex, extensive system. One of the drawbacks of relying on surface water is that precipitation levels vary greatly from year to year, making the majority of the state’s water supply relatively unpredictable – and highly prone to drought.
Each spring, the snowmelt evaporates into the air, seeps into the ground or flows as surface water runoff into river basins. Aurora’s water supply is derived primarily from the Colorado, Arkansas and South Platte river basins. Additionally, Aurora’s newest project, Prairie Waters, allows the city to reuse its precious water supplies, increasing the overall yield of the system.
Snowmelt begins in early May and continues until about mid-July. Once runoff begins, the water is captured and stored in our 12 reservoirs and lakes: Aurora, Henry and Meredith, Homestake, Jefferson, Pueblo, Quincy, Rampart, Spinney Mountain, Strontia Springs, Turquoise and Twin Lakes. These reservoirs can hold just over 156,000 acre-feet (a.f.) of water storage. Following runoff, storage levels decline throughout the remainder of the year as the city uses the water at a rate greater than any inflow to reservoirs.