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Chaucer-CS 960409 MEMORANDUM (~ To: Jim Witt, City Manager From: Kenneth M. Griffin, P.E., ACM/City Engineer ~ RE: Chaucer Estates Pond Date: April 9, 1996 As we recently discussed, I have attempted to develop a rough cost estimate on what it would take to remove siltation from the Chaucer Estates Pond. To make my best guess on the amount of siltation in the pond, I reviewed the information provided by Patton, Burke and Thompson Engineering Consultants on the samples. The two samples on the western end of the pond showed anywhere from 11 to 14 inches of siltation. The one sample on the far east side of the pond showed approximately 24 inches of siltation and the additional sample taken near the outfall in the middle of the pond showed approximately 32 inches of siltation. Using those amounts of siltation, I estimated that approximately 50% of the pond area had 1 foot of siltation, 30% of the pond area had 2 feet of siltation and 20% of the pond area had 2 1/2 feet of siltation. For the surface area of the pond, I used the standing water surface area which is about 32,600 square feet. Using those estimates, I came up with approximately 1950 cubic yards (CY) of silt to be removed. To arrive at the cost to remove the siltation, I reviewed estimates of cost generated for removal of silt from the Duck Pond. Those ranged anywhere from $12 to $18 per cubic yard. The basic difference between this and the Duck Pond is that the Duck Pond allowed areas for the contractor to remove the dirt and stock pile it on-site to be dried and/or removed at a later date. The Chaucer Estates pond does not allow that opportunity. Therefore, I used $20 per CY for the silt removal. Using those numbers, I estimate the cost to be approximately $39,000 to remove the silt from the pond. This is a rough estimate as it is based on only four samples obtained within a surface area of over 32,000 square feet. The Homeowners working directly with a contractor may be able to negotiate a better price. You may recall that recently I mentioned that to make our connection from the drainage system in Town Center to the pond may necessitate the draining of the pond. At that time, there could be coordination by the Homeowners group to better define the areas of the silt to more accurately define the amount of silt to be removed and/or work with the contractor or their own contractor to attempt to remove the silt while the lake is drained. Removing the silt while the lake is drained makes the most sense from an economic standpoint and could actually reduce the cost mentioned above. If you should have any questions concerning this please feel free to contact me at your convenience.