Imperial Reservoir Imperial Reservoir The Imperial Reservoir is an artificial lake formed by the construction of the Imperial Diversion Dam across the Colorado River in the Lower Colorado River Valley of Imperial County, California, and Yuma County, Arizona. A component of the Imperial National Wildlife Refuge, the reservoir is northeast of Yuma, Arizona. Dry washes are the major watershed feed systems to Imperial Reservoir. The next upstream major watershed feeder is the Bill Williams River from western Arizona. Upstream on the Colorado River, the basic feeder watershed to Imperial Reservoir is the Havasu-Mojave Lakes Watershed, of Lake Havasu. Two dry wash watershed
Imperial and US customary measurement systems ounces (of 437.5 grains). The unit of volume, the gallon, has different values in the United States and in the United Kingdom – the US fluid gallon being about 0.83 imperial gallons and the US dry gallon being about 0.97 imperial gallons. Both systems of measure were widely used in mechanical engineering, though not in electrical engineering. Some units of measure such as the horsepower or the British thermal unit (BTU) have special names but by and large unit names are generated from their constituent components – for example, pounds per square inch. In contrast, the metric system has a