Agmt09 Huffman-Broadway Group, Inc

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Facing a potentially narrow dredging work window and the associated urgency of obtaining the authorizations as soon as possible, HBG moved forward with the work, resulting in budget overages for Tasks 1, 2, 4,5, and 7 within Phase 1 and Task 5 within Phase 2. The additional services were necessary to obtain federal and state approvals and are reflected in the enclosed invoice #8401187 which includes work performed up until August 30, 2009. A description of these additional services and tasks follows: Phase 1: Maintenance Dredaina and Disoosal in Uoland Location or Authorized Disoosal Site Task 1. Prepare Consolidated Dredging-Dredge Material ReuselDisposal Application: The Project was anticipated to face minimal permitting delays, given that (a) its proposed disposal site had already been permitted with (b) a condition that supported clean fill material being placed in a borrow ditch that ( c) previous engineering estimates indicated would contain the bulk of the material that the City of Redwood City was seeking to dredge from the Lagoon System. In addition, chemical and grain-size analyses that had been previously performed in 2006 by Kinnetics Laboratories, Inc. (KLI) on the Lagoon sediments suggested that the materials would be determined to be "suitable" for disposal at a wetland restoration site. HBG moved forward to obtain a suitability determination from the DMMO, an interagency group that reviews proposed dredging projects, and seeks to identify beneficial re-use of the dredged material, where DMMO determines that the material is suitable for such uses. HBG sought to move the project forward without additional chemical testing (a Tier 1 exemption sought by KLI), but alerted KLI that DMMO might raise questions about 1) dredging Zone 16, where KLI had observed toxicity to polychaete worms in laboratory tests, and 2) an area where chemical testing of a composite of several sediment cores (Composite C) had reported concentrations of P AHs several times higher than other areas that had been sampled. When HBG, accompanied by KLI and Moffatt & Nichol, presented the project to DMMO in May 2009, DMMO did, in fact, raise questions about the polychaete toxicity and the elevated levels of P AHs in Composite C. In particular, the Regional Water Quality Control Board (Regional Board) requested that additional sediment samples be taken in the same locations at the original cores that made up Composite C. That sampling was completed and analyzed quickly by KLI, and the results were reported to the Regional Board. These samples showed that the P AH contamination was more wide-spread than anticipated, and the Regional Board refused to consider any of these sediments suitable for disposal at Area H without additional sampling. Those samples were also taken, analyzed and presented to the Regional Board, which determined that portions of Zone 9 were unsuitable for disposal, but that other areas were suitable. J:\Redwood Lagoon Dredging\Pl'oposal\Revision 2 Redwood Lagoon Budget Amend 10-14-2009.doc 2