REPORT - The Township of Uxbridge

Page 2February 27, 20122.3 Grading between lots 7 and 8 shall be revised so that positive front yard drainage isachieved.2.4 The elevation 265.98 between lots 9 and 10 appears incorrect and shall be revised.2.5 Tie-in elevations for the curb shall be provided on Oakside Drive.2.6 The road grade shall be revised so that a maximum road grade of 5% is achieved.2.7 The existing catchbasin on Oakside Drive shall be relocated to the edge of curb for at theproposed roadway entrance.2.8 A 0.3m reserve shall be provided along Oakside Drive.2.9 The grade at the top of CB1 appears to be incorrect. Please revise.2.10 A catchbasin shall be installed at the rear of lots 4 and 13.2.11 The location of the guiderail on the plan is different than what was observed in the field.Please revise.3. Stormwater Management Report prepared by Cole Engineering3.1 In Section 3.0 Design Criteria and Methodology, the criteria for no net increase inphosphorous loading should be added.3.2 Section 4.2 describes the post development hydrologic model as well as Figure DAP2,Appendix B. Uncontrolled flow is mentioned for the rear of lots 8 and 9 within paragraph 2,page 5. However the Figure DAP2, the Visual Otthymo model and the lot grading planshow that rear of lots 8, 9 and 10 will discharge uncontrolled. Please correct thisdiscrepancy.3.3 Section 4.2, next paragraph describes a total imperviousness of 45% for the development.DAP2 depicts a runoff coefficient of 60, while the Visual Otthymo Model uses Ximp of 18%and Timp of 45%. Please justify and clarify these numbers. The CN of 68.8 in the postdevelopmentcondition should be explained and justified with calculations3.4 Section 4.3, stormwater quantity controls are proposed through use of a bioswale orinfiltration facility. The design and end result of these two methods are very different,please clarify which method will be specified. Table 4 describes the required storagevolumes as calculated by the Visual Otthymo model but the stage storage dischargeinformation for the proposed facility. Please provide this information as well as preliminarygrading details for this facility. In addition please show an outflow route from the facility tothe receiving watercourse.3.5 Please show preliminary grades for the overland flow route shown between Lots 6 and 7from the curb to the stormwater management facility as well as required conveyancecapacity. The overland flow route will need to safely convey the Regional Storm Flows.First Submission Comments Nov 09 2010.Doc