7301 HARDESON RD 2019-01-11 - Laserfiche WebLink

f File No. 0643-013-00 September 6, 2018 Page 2 At 1056 the first load of utility sand backfill arrived(see attached sieve analysis, Figure 1). Dump trucks were unloading at the bottom of the access ramp in the southwest corner of the pond. Utility sand was being spread from west to east across the pond bottom using a small dozer(Photo 3). At 1330 the entire pond bottom had been excavated to Elevation 422 Feet and nearly all silty fill material had been over-excavated and removed from the pond bottom.The silty fill bowl-shaped wedge was observed to extend to the northern and southern pond edges,although it was pinching out and becoming thin at the edges.All silty fill material was removed to meet the infiltration design criteria and pond bottom preparation requirements.The over-excavated bowl-shaped area measured approximately 80 feet long by 40 feet wide by 3.5 feet deep in the center(becomes thinner toward the edges).The compacted haul road had also been removed. Utility sand continued to be brought into the pond and spread from west to east using the dozer(Photo 4).The pond bottom will be backfilled to Elevation 427 Feet,as designed.A sample of the utility sand was collected for grain size analysis(see attached Figure 1). We left the site at 1400.