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HomeMy WebLinkAboutSHENANDOAH P.U.D., FIRST FILING - FINAL - 47-95A - CORRESPONDENCE - DRAINAGE REPORT (3)4. An inverted siphon is shown for the realignment of the Louden Ditch. Please check with the ditch company regarding the design of the inverted siphon. How will the siphon be maintained? The inverted siphon should be modeled with the rest of the canal. Provide a letter from the ditch company stating their agreement to the inverted siphon. 5. The City standard parameters for max. infiltration .50 and min. infiltration .52. These are the values being used City wide. Please use these values for this development. 6. The basin maps on pages D-9 and D-10 show basins H1 and D1 as draining directly to College Ave. It appears that a portion of this area may drain to the 48" RCP culvert. Please verify where this basin drains. Also, the developed condition may not be able to drain developed runoff directly into College Ave. right-of-way. This area may need to drain into the existing 48" culvert. 7. The program used for the storm sewer analyses is not the typical program used and accepted by the City. Please provide further information on the assumptions and calculations used in the program. Please submit a comparison between this program and UDSewer. The program output does not give any indication of bend or lateral losses. 8. The proposed grading plan needs to be clarified. There are several areas where proposed contours cross other contours, do not match, or do not tie in. Please revise the grading plan. 9. Please show all utility crossings on the storm sewer profiles. 10. The deflector curb inlets are not standard inlets accepted by the City. These inlets are subject to further review by the City. Please refer to the redlined plans and report for additional review comments. PROJECT COMMENT SHEET City of Fort Collins Current PLwning DATE: ) /3 /9 7 .: DEPT: Stormwater PROJECT: PLANNER All comments nnusf De received by: ❑ No Problems 0_�_`Problems or Concerns (see below or attached) 1. A portion of the Benson Lake swale is outside the property boundaries of the First Filing. A drainage easement will need to be dedicated for the swale. Provide the drainage easement by separate document with the next submittal. 2. More information is needed on the Benson Lake inlet Swale. The existing condition of the swale should be verified on both sides of College Ave. The capacity of the swale should not be exceeded. Please provide swale cross -sections for both sides of College Ave. Unstable slopes in the swale will need to be stabilized. Outlet protection is needed at the downstream end of the culvert. 3. Please provide written verification of the Louden Ditch flows and the Benson Lake diversion. The flows should be documented in a signed letter from the ditch company. Please revise the calculations for the flow diverted to the Benson Lake swale. Date: ' �? signature:._ CHECK ff YOU WISH TO RECEIVE ❑ PLAT Cc s/ae�; wural��� 5�ue O if - COPIES OF REVISIONS ❑ STTE Na GPM ty ❑ LANDSCAPE Co%rVo Gono/r-'iora' 13 LTTH=