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Simplot, Don Plant Bathymetric Mapping


The Simplot Don Plant was constructed west of Pocatello in 1944, and was the first fertilizer production facility built by the J.R. Simplot Company. When production began in the 1940s, the Don Plant produced less than 1,000 tons of phosphate products annually. Today the plant produces over 1,000,000 tons of various phosphate fertilizers, feed phosphates, and industrial products annually. In the production of fertilizer, the Don Plant annually uses 1.8 million tons of phosphate ore. The byproduct of the fertilizer making process, phosphogypsum (gypsum), is slurried with water, pumped, and stored in large areas (stacks) on site. Once on the stacks, the very low pH water is siphoned off and reclaimed to be used in the fertilizer manufacturing process. Knowing the amount of very low pH water in the ponds on the stacks has always been a critical variable in management of the gypsum stacks, which are growing at the rate of 2.3 million cubic yards each year. In the past, water volumes were calculated utilizing aerial mapping and depth measurements done by two people in a rowboat with weights tied to a rope. These surveys were conducted annually and only in the unlined ponds.

Simplot retained Keller Associates as the prime consultant to perform monthly water volume calculations. Within project budget and safety parameters, Keller Associates provided an efficient, safe, and accurate bathymetric survey system for the six ponds with a total area of 130 acres. The following benefits have been realized:

  • Accurately determined edge of water and surface elevations of the ponds using high definition aerial mapping;
  • Eliminated the need to have surveyors exposed to dangerous conditions in a rowboat or on unstable shorelines by utilizing a remote-controlled boat equipped with survey-grade GPS and sonar; and
  • Provided six times the amount of volume data previously collected within a one-week turnaround.
  • First Place 2016 ACEC Idaho Engineering Excellence Award for Surveying and Mapping.