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feet wide and 1,500 feet long. A subsequent modificataon was issued to install manholes for the
<br />subdrains and an additional 2,100 tons of material for a new wing dike south of the National
<br />Cemetery.
<br />John Martin Reservoir: The inflow to the dam filled the reservoir to the top of the conservation
<br />pool at 1500 hrs on May 2, 1999. Flood control operations started accordingly. John Martin
<br />Project staff azranged for an aerial inspection of the Arkansas River above John Martin Reservoir
<br />to be done on Sunday May 2, 1999 and Monday May 3, 1999. On May 2, 1999,, John Martin
<br />Dam was releasing 1,400 c.f.s. through the sluicing conduits while t~7e inflow w~~s at 15,644 c.f.s.
<br />and rising. Operation of the tainter gates does not commence until t;.ne flood control storage
<br />space is filled. The tainter gates were not used for this flood event. On May 3, ~ 999, as a result
<br />of rapid rise in stage at the reservoir, personnel were dispatched from the Corps ~f Engineers
<br />Albuquerque District office to assist the project office with field inspection of the project. The
<br />district's PAO officer was also deployed to John Martin Reservoir. A peak inflaw of 30,000
<br />c.f.s. was measured at noon on May 3, 1999. By May 4,1999, the reservoir rose pasi the
<br />previous record pool elevation of 3,856.80 feet set on May 31, 1987. Daily field observations
<br />were in effect; including instrument readings and monitoring of seepage flow. Surveillance and
<br />onsite inspections were conducted in accordance ER 1110-2-100, Periodic Inspec~tions and
<br />Continuing Evaluation for Completed Civil Works Structures. Reservoir releases were increased
<br />to 2,000 c.f.s. on May 5, 1999. At 1700 hrs on May 9, 1999, the John Martin Reservoir crested ~
<br />at a new record pool elevation of 3,860.45 feet, corresponding to a reservoir volume of 456,004
<br />acre-feet. Of this total volume, 111,350 acre-feet was flood storage, which equates to
<br />appro~cimately 43 percent of the flood control volume filled.
<br />The morning of May 12, 1999 at 0600, the pool elevation at John Martin was 3,86038 feet; still
<br />about 4 feet above the previous record pool elevation. The total volume in the re~ervoir at that
<br />time, including the conservation pool, was 465,044 acre-feet. The dam was being operated to
<br />maintain a flow of 3,000 c.f.s. at the Coolidge gauge, located in Coolidge, Kansa:~. The releases
<br />from John Martin Dam were maintained between 2,500 and the maximum allowa.ble release of
<br />3,000 c.f.s. for a period of 5 weeks to drain the flood control pool. On June 10 with the pool
<br />elevation at 3;853.74 feet, the releases were being reduced by 300 c.f.s. per day from 2,900 c.f.s.
<br />The gradual reduction in flow will allow saturated banks to drain slowly and pre~rent sloughing
<br />of the river banks. Drawdown of the reservoir from the new record peak down below the flood
<br />pool was finally achieved over eight weeks later on July 6, 1999 at 1000 hrs. Rel~ases we:e then
<br />made based on irrigation demand.
<br />John Martin Dam South Wing Wall: Seepage was noted along the toe of the Sou1h Wing Wall at
<br />the dam on May 12, 1999. Work crews from the John Martin Project Office placed f lter fabric
<br />and approximately 10,000 cubic yards of material in this area to stabilize the area. District
<br />personnel inspected the seepage on the aftemoon af May 12, 1999. It was determined that the
<br />seepage was passing through the rock foundation under the embankment and was expected.
<br />There was no threat to the dam. The John Martin Dam-South Wing Dam foundat~on is
<br />comprised of alluvial sand underlain by sandstone and shaley sandstone bedrock. As a
<br />precautionary action, the Corps contracted to construct a seepage control berm at 1he toe of this
<br />Chapter 3- Flood ofApril ?.9, 1999
<br />Post Flood Assessment Report ~ 24 ~ Drajr Revtsea' 09/09/99
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