Laserfiche WebLink
— ^ *>v <br />\/( ;.j * <br />341.S <br />N Sk'ffnmer <br />-Outlet Structure <br />Bonearoo, Botene Andcrl k jmd Associ.nel Me is an Alfirrr.ivve Action equ.tl Jpportumty employer <br />rnncip.ili Otto G Boncitroo. PE • Josepfi C Anderlik. PE • Vrtfvin L SorvJlJ PE • <br />Richurd E Turner. PJ • Glenn R Cook. PE • Robert G Sfhunicm, PE • Jerry A Bourdon. PE • - <br />Robert * Roscnc. PE and Susan M Ebeilin. C PA Senior Consultants ^ <br />AssociMe PrnopKis Howard A Sanford. PE • Ke.th A Gordon PE • Robert R Plefferic. PE • 2^ - I U <br />Richard W Foster PE • David O Loskota PE • Robert C Russek. .M A • Mark A Hanson PE <br />Mictiacl T Rautmann. PE • Eed K Field. PE • Kennetn P Anderson. PE • Mark R Rolfs. PE • <br />Stdney P Wilhc^mson. PC . L S • Robert F Kotsmith <br />Offices St ®aui. Rochester Wiiimar and St Cloud, VN • Milwaukee. Wl <br />i -'’ * ' <br />evt^ oc <br />1/1 Bonestroo <br />Rosene <br />Anderlik & <br />I Associates <br />Engineers & Architects <br />March 19, 1998 <br />Mr. Michael P. Gaffron <br />Senior Planning Coordinator <br />City of Orono <br />Post Office Box 66 <br />Crystal Bay, MN 55323 <br />Re; Andersen Subdivision <br />File No. 139-2321 <br />Dear Mike; <br />Yesterday we received a mailing from Otto and Associates that included a preliminary <br />a grading plan for the proposed seven lot Andersen subdivision. The site is located west of Old Crystal Bay Road South <br />(C.R. 84) in the northwest quarter of Section 9. We have reviewed the submittal and observed that the plans an <br />calculations contained some errors and omissions. <br />The grading plan shows a storm w.ater pond in the eastern corner of Lot 7. It appears that the pond ^ <br />a wetland on the east end of Maxwell Bay. The draft version of the City s Surface Water Management Plan ( ) <br />classifies this wedand as being moderately susceptible to nutrient and .sediment loading. We recommend that pond <br />cakulatioiis be submitted that i-kntif> both pre and post development peak flows and nutrient loadings. In <br />with the SWMP .tr. .l to protect tlie downstream wetland, post development flows and nutrient loadings shou u no <br />pre development conditions. <br />We also recommend that the following information be submitted or corrected; <br />• A detailed drainage area map clearly showing pre and post development drainage arexs. size of areas, runoff <br />coefficients used and any assumptions used in the calculations. <br />. Calculations showing pond sizing to meet NURP standards for the drainage area reaching the pond should be <br />provided The calculations submitted show that the pond is sized to treat the entire site (17.5 acres). <br />. Corrected pool volume calculations. The contour areas provided in the calculations do not match the pond contour <br />areas as measured on the drawing. <br />• Tf: pond should have ;> 10;1 bench at the por.d NWL to provide a barrier of safety. <br />. 1 he storm sekver design should be clarified. Do flows from CBMH1 go to CBMH2 and then to MH1 ? Plans should <br />show pipe sizes, pipe length and grade. <br />• Storm sewer calculations should be provided to verify the proposed design. <br />• Outlet struciu'c details and design should be provided. <br />. A revised plan set should be submitted that shows specifically where the downstream drainage from the pond goes. <br />If tlie City chooses to construct the trail south of the Luce Line on the west side of Old Crystal Bay Road, it is our <br />recommendation that the trail be graded along the ca.-t edge of the Andersen property as pan of this project. <br />Please contact me ni ((n»4 4863) if you have any questions regarding this matter. <br />r^i: 1 • <br />C. LJ ' <br />r. <br />Yours ver, iFu'y. <br />BONIESIKOO. ROSENF, ANDERLIK & ASSOCIATES. INC. <br />Tom Kellogg