History Recycled: Capitol Hill Reservoir #2

When Cap Hill #2 was built, the population in the neighborhood was pretty sparce. Looking NE across the site. [Click for a larger image.]

In February 2006, Denver Water began demolition of Capitol Hill Basin #2, a reservoir that served the city for nearly a century. An attempt was made to modify the old structure so that it could hold recycled water, but the old concrete walls let water seep into the surrounding soil. Seepage of potable water does not pose risks to the neighborhood. Regulations and health concerns do not permit similar seepage for recycled water, however. After determining that the basin could not be sealed economically, the decision was made to demolish it.

In 1887, when the Congress Park/Cheesman Park area was known as Cemetery Hill, the first Capitol Hill reservoir was built to hold water from Cherry Creek. In the following years, a pumping station was added with steam pumps to move the water to homes in the Capitol Hill area. Basin #2, built just east of Basin #1, went into service late in 1906. It was much bigger than Basin #1 and held roughly 100 acre feet, a few days' worth of water for Denver's population of 150,000. In addition to serving the Capitol Hill area, the basins served downtown by gravity flow.

Basin #2 was roofed with wood for more than fifty years, and photographs of the interior show shadowy pillars rising from murky water.

The view from inside, 1916. [Click for a larger image.]

For decades, the Cap Hill basins would hold a blend of Cherry Creek water and water from the South Platte, until Cherry Creek water was finally dropped entirely in favor of the South Platte. In 1916 a new steam pump was added to move the water from the reservoirs, only to be replaced twenty years later, in 1935, by a newfangled electric pump. In 1947, Basin #1 was expanded and roofed in concrete. (Basin #2 did not get a concrete roof until 1972.) In 1955, Basin #3 was added for a total storage of 80 million gallons. Fifty years later, this proved to be more short-term storage than the area needed. Water in the service area reservoirs is moved within a week when possible, but the three basins held more than a week's supply for their portion of the service area.

In 2003, Basin #2 was taken out of service in anticipation of its rebirth as a part of the separate system of treatment, storage, and delivery that provides recycled water for non-potable uses. When it was found unsuitable for that task, it was slated for demolition. The roof came down in February of 2006.

The new reservoir was completed in 2007. It holds six million gallons compared to the old reservoir's 30 million. The portion of old Basin #2 that the new reservoir did not replace was leveled and filled.

Basin #2 saw a hundred years of service, evolving to meet the needs of a maturing city and the changing demands of its population. Its history reflects Denver Water's constant commitment to providing a safe and sustainable water supply, using the best technology and human wisdom available.

[Above] In 1906, construction work often meant steam power collaborating with man and mule. The sloped walls of Capitol Hill Basin #2 are taking shape in the background. Looking NW. [Click for a larger image.] [Right] Today's giant tools took down the roof in two days. Demolition Work, February 9, 2006, looking NE. [Click for a larger image.]