Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/908212
Bill Langer is a consulting research geologist who spent 41 years with the U.S. Geological Survey before starting his own business. He can be reached at Bill_Langer@hotmail.com CARVED IN STONE 32 AGGREGATES MANAGER / December 2017 B ack in the early 1990s, I was studying the gravels of Clear Creek near Golden, Colo. One beautiful fall day, I was look- ing at a residential lake development near Clear Creek that was built surrounding a water-filled reclaimed gravel pit. I was on the public sidewalk being mindful to not trespass or disturb the residents. I was deeply engrossed in "framing" my camera for a picturesque photograph between the houses when I was startled (putting it mildly) by a loud voice from behind. "Who are you, and what are you doing?" "I am a geologist with the U.S. Geological Survey, and I am studying residential lakes," I replied. That temporarily calmed down my accuser. I went on to say what a beautiful lake it was and how lucky they were to live there. That was met with a big smile, but the smile turned upside down when I went on to say that it was a marvelous use for a reclaimed gravel pit. "There is NOT a gravel pit! It is a natural lake!" To make a long story short, I finally diffused the situation when I said that the natural floodplain lakes around Golden often are created by floods and come and go at the whim of Mother Nature. Their lake, on the other hand, was well designed and would outlast what Mother Nature had in store for her own lakes. Time-travel backward a decade. Water law is a serious issue in the arid to semi-arid west. Colorado and Nebraska have an agreement that Colorado will allow no less than a specified amount of water to flow along the South Platte River from Colorado to Nebraska. The problem is that most of the flow of the South Platte comes in the spring from the melting of the snowpack. Millions of gallons of water flow into Nebraska, far exceeding the amount required under the Colorado-Nebraska compact. To remedy this, the Two Forks Dam was proposed to be built on the South Platte River, near Deckers, Colo. However, the permit to build the dam, which would have held enough to meet the annual needs of 400,000 people, was denied. Now, fast forward to the start of the 21st century. Just about the time Two Forks was dying, state mining engineers de- cided that mined-out gravel pits could be used as storage reservoirs. That decision changed the way aggregate companies and local municipalities looked at the pits. Not only could aggregate companies get the economic benefit from the gravel, but they could turn the mined-out land into a water storage facility for the nearby communities. Municipalities along the South Platte scrambled to permit new gravel operations, as long as they could purchase the hole. Gravel operators were happy to oblige because, frequently, the holes in the ground were worth more than the gravel that came out of them. Some rock quarries also became suitable storage places for municipal water supplies. Pictured at the right is one of those quarries, just start- ing to be filled. With the decline in the construction of new dams, this phenomenon has spread across the country. In some places, "Not in My Back Yard" has become "In MY Back Yard, PLEASE." AM During the past year, this column has discussed some environmental friendly uses of aggregate. This article describes an environmentally friendly use for the hole left behind after the gravel is mined. Not In My Back Yard