Antero Reservoir Timeline

1892	The High Line Canal was built to irrigate 50,000 acres of cropland and supply water for municipal and industrial needs of Denver. However, the canal had a junior water right, causing it to go empty during drought years. To supplement that water supply, the High Line Reservoir Company was founded to build a reservoir that would supply water to the canal.
1907	Three owners juggled management of the reservoir construction. The final construction cost was a mere $125,000.
1909	The reservoir finally was completed by Canfield and Shields of Greeley. The reservoir was called Antero because Antero is the Spanish word for first, and Antero is the first reservoir on the South Platte River, nearest to the river’s headwaters. Antero was designed to hold 85,000 acre-feet of water; however, four years later, Colorado’s Office of the State Engineer discovered failed concrete facing and limited the reservoir’s capacity to 20,000 acre-feet.
1915	Antero caught the interest of Denver, which devised plans to buy Antero and the High Line Canal as a source of municipal water. The city of Denver initiated a secret purchase of both Antero and the canal, but because of litigations and opposition, the purchase took almost 10 years to finalize.
1918	Denver residents bought the Denver Union Water Company for $14 million. The new Denver Board of Water Commissioners concentrated first on the South Platte River as a source of water supply. The Water Board saw Antero as a source of upstream water storage with access to the top of the watershed.
1924	The Denver Water Board finalized the purchase of Antero and took ownership of its storage rights. The High Line Canal and its direct flow rights were part of the purchase. Antero was a source of water that supplemented the High Line Canal when river flows were inconsistent. Diverting water from Antero to the canal helped irrigate Front Range agriculture.
1955	No one knows exactly when the public began to fish at Antero, but photographic records show Antero officially opened for recreation in 1955. The first records of recreation at Antero referred to it as “bare bones recreation.”
1959	Denver Water developed an agreement with the Colorado State Parks and Recreation Board to permit boating on the reservoir, which expanded recreation opportunities.
1990s	Denver Water began to more closely manage recreation, while the Colorado Division of Wildlife focused on maintaining Antero as a fishery. Antero, a perfect environment for the aquatic plants common in trout diets, was kept well-stocked by wildlife officials and continued to draw fishing enthusiasts.
1997	Denver Water drained Antero to make repairs to the outlet tunnels and kept it empty for one year until all maintenance work was complete.
2002	Denver Water drained Antero during the worst part of Colorado’s drought to prevent evaporation loss. The utility had to leave Antero empty for four years. Upon refilling, Denver Water temporarily closed Antero to recreation and designated it as a water storage facility only.
2007	Antero was reopened to recreation. This same year, a fisherman at Antero caught the heaviest cutbow trout on state record, weighing 18 pounds, 8 ounces.
2008	Denver Water and the Colorado Division of Wildlife started an effort to prevent the spread of zebra and quagga mussels by requiring boat inspections for all vessels used in the reservoir.
2009	Antero celebrates its 100th anniversary as an important water storage site for Denver Water customers and as a recreation amenity for all Coloradans.