Morris Dam (officially the Samuel B. Morris Dam) is a concrete gravity dam across the San Gabriel River in the U.S. state of California. It impounds Morris Reservoir, directly downstream of San Gabriel Dam. The dam was built in the 1930s as a water supply facility for the city of Pasadena, but is now mostly utilized for flood control and flow regulation for groundwater recharge. Situated in northern Los Angeles County, the dam impounds the Morris Reservoir in the Angeles National Forest, a few miles northeast of Azusa. From the 1940s to the 1990s, the reservoir was also used for underwater missile testing by the United States military. Design and location This dam sits south of Silver Mountain and north of Glendora Ridge, which flank the deep San Gabriel Canyon. It is roughly upstream of the San Gabriel River's mouth at the Pacific Ocean, and downstream of the river's beginning at the confluence of its East and West Forks. Morris Reservoir is about long and above sea level at maximum pool, covering . The dam's crest itself is at an elevation of . Serving mainly flood control, flow regulation and groundwater recharge purposes, the slightly arched Art Deco-style gravity dam is high and long. Its spillway, located slightly north of the main structure, is a concrete-lined chute controlled by three steel drum gates. The reservoir created by the dam, when first put into use, was capable of storing . Due to sedimentation though since that time, its capacity has been reduced by about 29%. At present, the reservoir when filled holds approximately . History Morris Dam was originally slated to be called Pine Canyon Dam, but was renamed for the chief engineer of construction, Samuel Brooks Morris of the Pasadena Water Department. With the dam envisioned as a private structure for Pasadena, groundbreaking was in April 1932 and construction was completed in May 1934, four months behind schedule. Upon completion the dam was dedicated by former United States President Herbert Hoover. In 1935, contrary to its original purpose, Morris Dam was sold to the Metropolitan Water District of Southern California (MWD), which owned it through most of the 20th century. The dam was completed prior to the catastrophic Los Angeles Flood of 1938, the most severe flood recorded in Southern California since the Great Flood of 1862. Along with San Gabriel Dam, which at the time was under construction, the