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HomeMy WebLinkAboutMOUNTAINRIDGE FARM PUD, FIRST FILING FINAL - 18 92C - CORRESPONDENCE - MEETING COMMUNICATIONMEETING MINUTES Project: Regional Detention Pond 247 and Open Channel (Shields to Benthaven Streets) for the McClellands and Mail Creek Basin Project No.: 504-009 Date: September 7, 1994 Time: 10:30 am - 12:30 pm Location: City of Fort Collins Stormwater Utility Attendance: City of Fort Collins Stormwater City of Fort Collins Stormwater City of Fort Collins Stormwater RBD - MountainRidge Farm PUD rep. MountainRidge Farm PUD rep. ITEMS DISCUSSED: Lincoln Mueller - Glen Schlueter Basil Hamdan Kevin Gingery Gary Nordick Dennis Donovan The following quotes were pulled from the City Stormwater Utility's review of the MountainRidge Farm PUD Regional Detention Pond 247 comments and clarification is needed on these items before we can begin to address them. 1. "..The open trench washed rock will present silting problems and might get clogged, thus preventing the bottom 4 feet of pond from draining easily. The volume available for detention should be counted only from the invert of the pond outlet (not the bottom of pond) since that volume between the invert of the 27" RCP and the pond bottom does not have a positive functioning outlet that can be maintained free of clogging." Because this concept was approved with the preliminary design, can we simply add area inlets throughout the pond bottom that provide a direct connection of the pond bottom to the underdrain system, to obtain credit for the bottom 4 feet of the pond volume? ANS: Ok to add 3 area inlets along the north -south underdrain line within the 5074 bottom contour. Then the bottom 4 feet of the pond volume can be counted in the overall detention pond volume calculations as currently shown. The area inlets will require erosion control inlet filters. A portion of the 5074 contour (pond bottom) adjacent to the trickle channel should also contain an excavated area for silt accumulation. Per a telephone conversation with Glen later in the day, an additional meeting has 1 been scheduled with Glen, Kevin McBridge (Stormwater Utility) and Kevin Gingery for Thursday September 15, 1994 at 3:00 pm at the Stormwater Utility office to discuss the need for the regional detention pond to include an 'Extended Detention" mechanism per the latest Urban Drainage & Flood Control District criteria. 2. "The 36" Storm Drain coming from the Westbrook 2nd development should be designed along with this project." We believe that this design is being done by the engineer for the Westbrook 2nd development and that it is his responsibility to show the regional detention pond on his drawings and coordinate with us for the interface. We believe that it is only your responsibility to show the 36" line for reference only, because the 36" line is not a Regional Improvement and should not be paid for by the Stormwater Utility. Would the Stormwater Utility like to pay for the addition of this 36" line? ANS: Yes the Stormwater Utility would like to include the 36" line design in the Regional Detention Pond design from the detention pond trickle channel to the right-of-way of Wabash Street. RBD is to coordinate with Redpeak Engineering (engineers for Westbrooke PUD 2nd Filing). 3. "Please provide preliminary design of regional pond 278 (the upper pond) proving that the system would still work ultimately and that when the two ponds are finalized there will be enough room in that pond for all regional flows that were planned to be detained in that pond." This was done at the time of Preliminary Design, submitted to the Stormwater Utility, and approved by the Stormwater Utility. Because this work is within a future phase of the MountainRidge PUD, do we need to show all of the preliminary design again at this time on these Utility Plans? ANS: Ok to insert the Preliminary Grading/Drainage Plan into the back pocket of this report. Dennis is to get RBD a mylar sepia of this drawing. 4. "The regional outfall across the Church and .Chism Homes requires an easement that has still to be negotiated. Please note that this issue should be pursued by the developer not the Stormwater Utility." Because this is a Stormwater Utility capital improvement project component, why is the Stormwater Utility not going to negotiate these easements? SANS: RBD is to provide the legal descriptions and exhibits to Dennis and he will process the easements with the Stormwater Utility. 2 5. "This report must stand on its own, please include relevant data for all the storm drainage facilities installed on your site." RBD's insurance carrier and associated liability will not allow RBD to combine a final report with another firms report. RBD's work must stand alone for what ever components of the project RBD has been associated with in order for a professional engineer to sign and stamp a drainage report. ANS: Ok to split the project into two drainage reports by the two engineering companies. 6. "Please provide a landscaping plan for the pond for our review and approval." A landscape plan was submitted along with all other materials submitted to the planning office on July 18, 1994. ANS: RBD to provide the Stormwater Utility with a landscape plan at the time of our next submittal as they have not seen the plan. 7. "... the Stormwater Utility has not determined whether both drop structures might need to be rebuilt. This will be done after a field visit to check on the status of these structures." Has any decision been made as to the.use of the lower drop structure? ANS: The Stormwater Utility will look at the existing drop stricture and come to a conclusion soon. If the existing drop structure is to be removed and replaced, an opportunity will open up to shift the proposed underdrain north from its present location to the northerly toe of the channel slope (10 feet south of the north permanent easement line). If the underdrain is shifted, two temporary construction easements will no longer be necessary along the south side of the proposed open channel, and adequate room will exist to constrict the line without a trench box adjacent to the existing 15" sanitary sewer line. 8. "Will the canal be lined this fall prior to the construction of the rest of the improvements? A separate agreement may be needed for this work to be done earlier." What kind of separate agreement will be required for the canal lining to proceed this fall? ANS: The separate agreement will be in the form of a Memorandum of Understanding issued from Mike Herzig. 3 Glen will check with Mike to see if an Exhibit "B" Cost Allocation can be attached to the Memorandum of Understanding, so the developer can be repaid sooner. Three of the Utility sheets can be used to attach to the Memorandum of Understanding, those being the Regional Detention Pond plan and profile sheet, the PV&L Canal lining sheet, and the PV&L Canal relocation geometric sheet. To these sheets will need to be added Interim Erosion Control Notes, Ditch Company approval blocks, and a note along the drawing bottoms indicating exactly what the drawings are for (ie. For Interim Erosion Control, Canal Relocation Grading, Detention Pond Excavation, etc.). 9. "... an acceptable alternative arrangement must be designed for that irrigation lateral to be able to discharge into the Four Seasons' channel and ultimately into the Troutman Park pond. You will need to coordinate the design of that irrigation lateral with Virgil Taylor of the City's Parks dept...." Is the irrigation lateral required to be discharged through Regional Detention Pond 247? ANS: Dennis will follow up with Virgil Taylor as to the timing, location, concepts, requirements, and flow rates for the irrigation lateral. 10. "Please summarize in a table all the contributing 2 year and 100 year flows, from onsite and offsite basins. Please provide a drainage and a detention summary table on the plans." Is this a requirement of the Regional Detention Pond design drawings or the First Filing Drainage & Erosion Control Plan? ANS: A table with the 2 & 100 year SWMM Model output results for upstream contributory basin flow rates and areas should be added to the Regional Detention Pond drawings. 11. "...Address the slurry wall recommendation as part of the canal re -alignment. Discuss downstream impacts and mitigating measures in your report text." "...Please provide further discussion of the goal, design assumptions and the calculations for the underdrain system for the 2 year and 100 year water levels in the pond." Because the previous groundwater studies were done by other outside consultants, do we need to retain these consultants to re-evaluate the need for a slurry wall with reference to the currently proposed design? 4 ANS: Yes we need to retain these previous groundwater consultants to re-evaluate the need for a slurry wall and size the Regional Detention Pond underdrain. Dennis will provide Kevin 3 sets of Utility Plans for this analysis. 12. "A full sized sheet providing master plan subbasin delineation, supporting topography, conveyance elements, and detention facilities should be included." Is anything else acceptable? ANS: A full sized sheet should be provided and included as a task in the overall project scope. Dennis will provide Kevin with a mylar sepia base sheet for this'task. 13. "Detail crossing under the Pleasant Valley & Lake Canal including cut-off walls." What kind (earth or concrete) of cut-off walls would you like? Size? Thickness? ANS: RBD should utilize the current City standard details for the cut-off walls. 14. "0.4 % is minimum pipe slope" We were not previously aware of this criteria. Is this new criteria? Will you grant variances for pipes less than this slope? ANS: Yes a variance will be granted for the storm sewer line across Shields Street due to all of the utility conflicts within the street. A variance should be requested in the hydraulic report. 15. In addition to the above items, we discussed the fact that various items above were not included in RBD's original Scope of Work as is being handled by the developer repay program through Miramont Associates. An Authorization for Additional Services agreement will need to be prepared and approved before we can proceed with the additional work. Everyone understood this and Link asked for a copy of the Authorization for Additional Services once it has been developed. END OF MEETING MINUTES 5 m These meeting minutes have been prepared by RBD, Inc./ Kevin Gingery. Any corrections, additions and/or modifications should be forwarded in letter form to the following address: Mr. Kevin Gingery, P.E. RBD, Inc. Engineering Consultants 209 S. Meldrum Fort Collins, Colorado 80521 Prepared by: evin W. Ginge y, E. cc: City of Fort Collins Stormwater - Lincoln Mueller City of Fort Collins Stormwater - Glen Schlueter City of Fort Collins Stormwater - Basil Harridan RBD - Kevin Gingery MountainRidge Farm PUD rep. - Gary Nordick MountainRidge Farm PUD rep. - Dennis Donovan 2