The Tacoma water flume was built in 1885 to carry water from Spanaway Lake to a reservoir near downtown Tacoma. The open wooden flume provided needed water to a growing city, but proved to be an unsanitary solution. It was only used for a few years before being replaced with a pipeline. The right of way for the flume and pipeline were also used as a walking and cycling trail, much of it built of wood held together with iron straps. 
In 2014, the City of Tacoma opened this urban trail along the 130 year old historic right of way that still exists today. The trail is currently just over two miles in length, but within a couple years will extend a total of 6.5 miles to downtown and join with other existing trails. It passes through South End neighborhoods, past two schools and through two parks. This cache is located at one of the largest pump station buildings along the trail.