Lake Eildon
The Eildon Dam or Eildon Weir, a rock and earth-fill embankment dam with a controlled spillway across the Goulburn River, is located between the regional towns of Mansfield and Eildon within Lake Eildon National Park, in the Alpine region of Victoria, Australia. The dam's purpose is for the supply of potable water, irrigation, and the generation of hydroelectricity. The impounded reservoir is called Lake Eildon.
The Location and Features
Designed by the State Rivers and Water Supply Commission of Victoria, construction of the original water storage, which was known as Sugarloaf Reservoir, took place between 1915 and 1929 to provide irrigation water for what was a vast uncultivated area on Victoria's northern plains. The dam was modified in 1929, and again in 1935 to increase the storage capacity to 377,000 megalitres.
However, this reservoir was still limited in its capacity to meet the growing demand for water in the Goulburn Valley and to protect farmers during drought years. Following a detailed feasibility study of all possible storage sites on the Goulburn River, it was decided that the existing dam site was the most suitable for construction of a larger dam. In 1951, work began to enlarge the storage to its present capacity. The enlargement was completed in 1955 and the storage was renamed Lake Eildon.
The embankment dam wall is constructed with an earth core and rock fill, rising to a height of 83 metres. The core component materials of the wall include 10,200 thousand cubic metres of rock and earth. With a catchment area of 3,885 square kilometres that includes the Goulburn, Delatite, Howqua, Big, and Jamieson rivers and several minor tributaries, the reservoir covers an area of 13,832 hectares. The reservoir has a capacity of 3,390,000 megalitres with an average depth of 24 metres, and can release a maximum outflow of approximately 3,356 cubic metres per second via its controlled spillway. The crest of the uncontrolled spillway is 288.9 metres AHD and is approximately 1,085 metres long.
Lake Eildon is connected to the metropolitan water supply of Melbourne, via a pipeline from the Goulburn River. On average, 91% of the water from Lake Eildon goes to the Goulburn Weir and the Waranga Basin before it flows to irrigators in the Goulburn Valley system.
The Cache
The container is a familiar object hidden inside another but different familiar object that should be recognisable to all but the most green of geocachers.
Oh, yeah. Where is my picnic table?
It's on the other side of the lake, somewhere directly opposite here.
