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HomeMy WebLinkAboutLot Certifications - 05/30/20080 Stantec ConsuNng Inc 209 South Meldrum Street Fort Collins CO 80521-2603 Tel: (970) 482-5922 Fax: (970) 482-6368 Stantec June 3, 2008 Mr. Jay Barber Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80522 Je .4 �� VIP .lam /� �,..,,�' i�7•�.��� Re: Drainage Certification for Lowes and Target at Front Range Village Dear Mr. Barber: The purpose of this report is to complete the drainage certification for Lots 15 and 11 (Lowes and Target respectively) at Front Range Village. King Surveyors visited the sites on several occasions between April 2, 2008 and June 2, 2008, to record inverts and rim elevations of the storm sewer manholes and structures, slopes of the storm pipes, and also topo the constructed ponds. Stantec Consulting Ltd. also visited the site on April 3, 2008, and June 2, 2008 to confirm the installation of the storm pipe, structures, and erosion control measures, as seen in the approved utility plans. The site visit focused on the storm drainage structures and appurtenances serving the Lowes and Target buildings, and also the grading around and adjacent to the Target and Lowes buildings. The proposed detention ponds, serving the storm water discharge from Lowes and Target, meet the intent of the approved plans. Stantec has included a copy of the surveyed detention volumes provided by the constructed ponds. Though Ponds A and D are short by 0.28 ac-ft and 0.16 ac-ft respectively of the required detention volumes, these shortages appear negligible. Ponds A and B would have to be raised approximately 0.18' and 0.05' respectively to meet the required volumes. Because both ponds provide 1' of freeboard (above the provided 100-year water surface elevations) and all ponds have been permanently seeded, Stantec does not feel re -grading the ponds is necessary to gain so little volume. V:\52877flactive\187710251\management\correspondence\letter_memos\Target & Lowes Drainage Cert 6- 2-08.doc Stantec Seeding, landscaping, and hard-scaping have been completed around and adjacent to the Lowes and Target buildings and provide positive drainage away from the buildings to the proposed storm drainage structures. It is important to note that hard-scaping/concrete paving is being installed on the north side of Building 1600, which will accept flows from the east side of the Lowes store and convey storm water to the proposed inlet north of Building 1600. The concrete paving will be completed within the next two weeks. The storm drain systems, which convey runoff from the Lowes and Target sites to their respective detention ponds, are installed and meet the intent of the approved plans. It is important to note that the Target site currently has risers for the landscape islands sticking out above finished grade. These landscape drain pipes will be cut off at finished grade, with inlets placed on the risers. This will be completed within the next two weeks. It is also important to note that there is one island in the Target parking lot that has not been landscaped to date. The island is occupied by temporary power pedestals that provide power to the construction trailers at the Target site. The trailers will be removed and island landscaped within the next month. Stantec will provide an "Overall Site Storm Drainage Certification", including record drawings for the ponds and storm drain structures and appurtenances at a later time. Therefore, this storm drainage certification is only intended to cover the Lowes and Target sites, as well as the grading around and adjacent to the buildings, and also the storm drain structures, appurtenances, and detention ponds that serve these two buildings. This certification is signed and stamped. By signing this letter, I attest that to the best of my knowledge, the conditions of the site are as shown on the attached redlined photocopy. Failure to properly disclose all known information could result in the rejection of this certification and prevent the release of any storm water utility holds on the Building Permit or Certificates of Occupancy. Thank you for your time and consideration of this submittal. Sincerely Yours, Stantec Consulting Ltd. : L e-k John Gooch Project Manager cc: Joe Johnson, Hoar Construction Dave Brown, Bayer Properties File V:\52877f\active\l87710251\management\correspondence\letter_memos\Target & Lowes Drainage Cert 6- 2-08.doc (2200) --------------4Yau- ----- _ r - -- --- -- -- ____--_ -- 1 / // /----------------- I / I li Pond A=7.36 �p ililt I II j1111 Required = 7.64 \ / Illill I I I \ li WSE=4927.81 II II Outlet Inv = 4920.47 r / /1 i li o l i i ' i 1� Weir Length = 140' Required Length = 140' �� Ilil // 11111. I I I I I I IPO D A / / I II IIII I � r I III II IIII I �' ' / 11111 I I I I' I �' 1 1 1 III 1 I / IIII i lilt I I I 'III I I / r II'I I Jill liltIIII IIII' I IIII I IIII , 1 I I I 11I I / / / / IIII lilt I ' �' // I I' I I I I I - - , / lilt ' I i I I � � III Ililt I I I l i I I II I � IIII /' / III ro IIII /� / III I. . ,R. .m.0 ---------------------- ;1 ai____________________ ------------------------------ Pond E = 1.25 Required = 0.92 WSE = 4925.12 \\ II II ' Outlet Inv = 4922.41 \\ ' Weir Length = 25' Required Length = 25' lilt POND E --------------� I I 11 --- Il L ___ . / _-_-_-_-_-_-_-_-4940---------------_-_-_-_-_-_-_-_-_' _ ------- pry ------------------4940----=' ----------_ � $bY--4938-' ---------.��� a --------'------ dli '19 FFF_ or //'i------- 4940---------------------------------------------------------------------------'� - - - - - - - - - - - - - - - - - - - - - - - - - /------------- - - - - - - - - - - - - - - - - - - - - - - - - - - _ _ _ _ _ _ _ _ _ _ _ _ _sr - - - __,r _ - -_ -_ _ _- ------------_-----_----___-_-_- _ _ _ _ _ _ _ - �935-_-_-_-_-_-_-_-_-_-_-_-_ _ _-_-_-_- - - -_-_-_-_- ----------- -- - - - - - - - - - - - - - - -- - -_ _ ♦�\\ \ _ -4932----------------------- --------------- -- ♦rg // /, /, /✓------4935---------------------------------- ---- -------------------------- ----_ ------ ------------------------------------------- - -- \\\ y — \ -- - - - - - ----------- -- _ ----- Pond D= 19.62 _-__49a0___ `I 1 1 Required = 19.78 IIII I A I � . 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