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Barr Engineering Company RECEIVED FED 2 :i_ 2008 4700 West 77th Street Minneapolis, MN 55435-4803 Phone: 952-832-2600 Fax: 952-832-2601 www.barr.com An EEO Employer ~ ~ ~, ~ , February 18, 2008 Minneapolis, MN Hibbing, MN Duluth, MN • Ann Arbor, MI Jefferson City, MO Mr. Mark Maloney Grass Lake Watershed Management Organization 4600 Victoria Street North Shoreview M1~1 55126 Re: Progress on Lake Owasso IJAA 23/62-946 Barr Invoice Period: December 2J, 2007 through January 25, 2008 Dear Mr. Maloney: The enclosed invoice is for professional services, which include the following: • Existing condition P8 model calibration runoff and pollutants • Development of continuous. water balance modeling to verify P8 runoff modeling results/estimate groundwater seepage ircluding the development of Lake W:abasso water balance to confirm Lake Owasso water balance . • Development of 20071n-lake water quality model (2-basin model) • Begin estimation of critical management climatic conditions • Development of 1995 - 2006 In-lake water quality model (1-basin model) including formatting WQ data for models and developing P8 for time period • Update P8 model for future conditions (land use and devices) • Writing of UAA report including development of tables and figures .~ ~.: • -:Development of technical memo of preliminary finding • Attendance at the January 24, 2008 GLWMO regular meeting Over the past month we have continued efforts to calibrate the surface water and in-lake models to the observed flow and water quality data collected by RWMWD and Ramsey ~;o~~nty. In additior. tc model calibration we have been working on the draft UAA report and a technical memorandum summarizing the project findings to date. Overall the project has fallen behind schedule due to the unforeseen calibration difficulties, such as Lake Owasso's outlet structure not functioning as designed, the Lake Wabasso outlet structure failing, and the atypical 2007 climatic conditions. The unexpected calibration difficulties have resulted in a cost overrun of about $5,115 associated with Tasks 004 and 005 (see table below). Also, as previously reported on the July 19, 2007 progress invoice report, the development of the Lake User Survey (Task 010) required more effort than originally anticipated which caused unforeseen c,osts.(e.g., unplanned meeting with stakeholders to collect input on the lake a"sef survey; manager's request. to development of an on-line survey in addition to the mailing; ~dditiorial postage relatedao the number of mailings; and associated project management tasks). 'In July 2007 we believed that the added casts for the unscoped Lake User Survey work could be.reeovered by other.comperzsating project efficiencies. However, the. , unexpected calibration difficulties exceeded all other project budget savings (lake sediment core