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<br />C:;) <br /> <br />( ': <br /> <br /> <br />DEPARTMENT OF THE ARMY <br />ALBUQUERQUE DISTRICT, CORPS <br />ENGINEERS <br />4101 Jefferson Plaza, NE <br />Albuquerque, New Mexico 87109-3435 <br /> <br />fI,)' <br />c) <br />t..:l <br />,a;. <br /> <br /> <br />May 13, 1998 <br /> <br />Operations Division <br />Reservoir Control Branch <br /> <br />Mr. steve Witte, Operations secretary <br />Arkansas River compact Commission <br />Colorado Division of Water Resources <br />P.O. Box 5728 <br />Pueblo, COlorado 81003 <br /> <br />Dear Mr. Witte. <br /> <br />On the dates of April 23 through April 29, 1998, several events occurred <br />which resulted in a loss of conservation storage in John Martin Reservoir. I am <br />writing this letter to explain the sequence of events that led to this and <br />identify steps we have taken to prevent a future recurrence. <br /> <br />On April 23 an employee of the state of COlorado replaced the encoder on <br />the John Martin reservoir elevation gage along with some electronic attachments. <br />The gage had been malfunctioning and though another individual had just fixed it, <br />the gage was determined to be at least 12 years old and needed replacement. At <br />the time of the gage replacement, the elevation from the gaging well was measured <br />using a drop tape and the gage reading was confirmed to be correct. There was <br />very little to no movement of the reservoir elevation over the next day and <br />weekend settings were made anticipating very little inflow changes. <br /> <br />".< <br /> <br />on Monday, the 27th at 8 a.m. , the gage reading was noted by the operator <br />and an increase in release made from 497 cubic feet per second (cfs) to 1,020 cfs <br />to evacuate what the gage indicated to be an excess of storage gained over the <br />weekend. The usual KondaY's manual check of the reservoir's e],evation using the <br />drop tape was not made because the operator had done this on the previous <br />Thursday. <br /> <br />The next day, the 28th at 8 a.m., the gage indicated the storage had <br />increased about 1,300 acre-feet. COrps' district staff hypothesized that the Ft. <br />Lyon canal may have been sluicing large flows back to the river below the Las <br />Animas gage, though that was not confirmed. The flow was increased to 1,495 cfs <br />at 9 a.m., 1,890 cfs at 11 a.m., and 1,966 cfs at 1.30 p.m. and 2,260 cfs at 9 <br />p.m.. At each of these flow increaoes the reservoir appeared to be gaining <br />elevation in spite of the release increases. <br /> <br />0</ <br /> <br />On the morning of the 29th, the reservoir gage indicated another 1,750 <br />acre-feet had been stored since 8 a.m. the previous morning. The reservoir <br />manager was in Albuquerque for a meeting and at that point a consensus was made <br />in the District office to direct the operator to use the tape and measure the <br />elevation from the well. After measuring the elevation the operator reported <br />that it was not 3852.22 as reported by the gage, but it was actually 3851.57. <br />This was 0.30 feat below the target elevation and approximately 3,460 acre-.feet <br />below the reservoir target volume. The flow was immediately cut to 1,320 cfs at <br />9 a.m. and then to 659 cfs at noon. District IItaff and the operator then decided <br />to increase the flow to 1,015 ofs at 1.30 p.m. to minimize the downstream impact <br />from previous flow ohanges. The operator attempted to contact Bill Howland <br />before thiB final change to confirm the handling of capturing back the storage <br />into the reBervoir but could not reach him. He had left that morning after <br />fixing the elevation gage with the IItatement that irrigation demand was about 640 <br />