2.4. ERMUSR 06-10-2014 - Laserfiche WebLink

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II. Statement of Purpose The purpose of this Emergency Action Plan (EAP) is to provide the owner/operator of the Elk River Dam with a clear plan of action when any dam emergency arises, with the intent of safeguarding the lives and reducing damage to the property of the citizens of Sherburne County living along the Elk River. An emergency is identified as any condition which: • develops unexpectedly; • endangers the structural integrity of the dam; and • could result in the dam's failure producing downstream flooding, requiring immediate action. This EAP provides information about the dam and contact information for all parties involved in responding to or affected by an emergency at the dam. The EAP outlines what actions are required in the event of an emergency. III. Project Description The Elk River Dam is located in Section 33 of Township 33 North, Range 26 West, within the City of Elk River, Sherburne County, Minnesota. The dam impounds the Elk River, forming Orono Lake, a recreational waterbody. The Main Street Bridge is located immediately downstream. The Mississippi River is located approximately one mile downstream. A location map is presented in Figure 1 on the following page. The Elk River Dam is a high hazard concrete gravity dam with a structural height of 15 feet, and a structural length of 207 feet. The dam consists of the following components, from left to right looking downstream: a concrete flood wall, an earthen embankment fuse plug, an abandoned powerhouse (foundation only), a fixed crest overflow spillway, a concrete tainter gate spillway with three steel gates, a fixed crest overflow spillway, and an earthen embankment fuse plug. A plan and section of the dam are presented in Figure 2 on page six. The contributing watershed area at the dam is 640 square miles. At a normal elevation of 871.3 mean sea level (msl) the pool is 281 acres, with a maximum depth of 18 feet. The normal storage is 1,600 acre-feet, and the maximum capacity is 2,800 acre-feet. The maximum discharge is 10,000 cubic feet per second. The nearest upstream dam is Eagle Lake Dam on a tributary to the Elk River, approximately 10 miles from the Elk River Dam. The nearest downstream dam is the Coon Rapids Dam on the Mississippi River, approximately 17 miles from the Elk River Dam. June 6, 2014 Page 4 48