R2019-209 Resolution Approving Change Order No. 22 to the Contract with Great Lakes Dredge and Dock, LLC for Lake Decatur Dredging of Basin 1-4 and the Rehabilitation of the Oakley Sediment Basin City Project W1314

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February ls`,2Q19 Page 4 Ref:R11021SRM/DSC/SL-032 � marsh buggy(s),exaavator,Ioader,and dozers,and(ii)dewatering utilizing pumps,(b)efforts not to fill the polishing pond with sediment and cause water quality issues,and(c}a LIDAR survey af the OSB performed in Feb 2018. These efforts were directly related to the OSB insn�cient capacity and attempting to rnitigate cost impacts to the City,trying to save cost by waricing to minimize the required height of the new dikes and saving the polishing pond in order to maintain water quality during the remainder of the project. We would not have needed such additional equipment,labor resources and survey if not for the lack of capacity in the OSB and GLDD's efforts to fit as much material into the OSB as possible aftempting to avoid an early shutdown. Atso,such efforts by GLDD aliowed nearly 60,000 cubic yards of additional material to be ptaced in the OSB beyond the OSB's initial design maximum capacity by Chastain. The Amount of this claim is$Sf?7,442,and the documentation and detail of tbe costs associated with this work Iisted above is provided in Eachibit 4. 5. Sg[JTDOWN/STANDBY FOR MQDIFICATION TO P4L�SHING POND&NIITGATING EFF012.TS TQ E7�TEND T�IE DREDGING SLASON&R�DU'CE STAND BY COSTS TO THE CITY By August of 2017,the overall OSB capacity shortfall was confumed by the GLDD survey(refer item 3 above). Thus GLDD attempted to at Ieast partially mitigate tb,e design error to extend dredging and avoid an earIy season sbutdown:by constructing a cross dike in the interior of the Polishing Pand to provide additional disposal capacity for the 2017 season. We requested and received two bids from subcontractors to build the dike. GLDD had to suspend dredging during this znitigatiou attempt from Octaber 10,2017 to October 30,2017 in order for the selected subcontractor,Beyer Construction,to perform the modifications. The attempted modifications to the polishing were ultimately unsuccessful due to rains and water levels making it impossible to build the cross dike during October 2017 and forward. Thus GLDD experienced three weeks additional shut down due to the OSB insufficient design capacity issue. The amount for this part of the claim is$592,050, and the docurnentation and details of the costs associated with this work listed above is provided in Eachibit 5. 6, EARZ,'�' SHUTDOWN/SYTSPENSTON FO�2 TH�2017 DREDGE SEASON Despite all GLDD's attempts to mitigate and mixumize impact to the City,ultimately due to the insufficient design capacity of the OSB and the continued concerns from tlie City af Decatur and Chastain in regard to main#aining three feet of freeboard at the exterior berms,it was determined that the OSB had reached capacity on or about November 19,2017 as communicafed to Chastain and the City via anr letter R1102/SRM/DSC/SL-031 dated November 17,2017. Thus GLDD incurred additional shutdown and stand- by costs from November I9`h until our planned winter shutdown date of December 23`�.The amount for this part of the claim is$409,860,and the dacumentation and details of the costs associated with this work listed above is provided in Exhibit 6. LII.CLAiM SUMMARY As detailed above and in the aitached Exlubits,our claun for the Berm Modifications af the Oakley Sediment Sasin due to Insufficient Contract Design Capacity is as foltows. Per Contract using IDOT Specification: , Exhibit 2—2418 Standby During Construction of Perimeter Bern�s of Cell D $798,556 E�chibit 3—Additional Dewatering&Survey During the Winter 2UI6/2017 Dredging Seasan $78,044 '�--� Exhibit 4—Additional Dewatering 8c Disposal Area Management Efforts 2017 Dredging Season $521,743 . Use or disclosure of dafa confained on this sheet is subJect fo the resfrictions on the f4tle page of this submis�lon.