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Home My WebLink AboutRIDGEWOOD HILLS RESIDENCES 4TH FILING - MAJOR AMENDMENT - MJA130003 - SUBMITTAL DOCUMENTS - ROUND 2 - VARIANCE REQUESTRIDGEWOOD HILLS LOW -IMPACT DEVELOPMENT IMPROVEMENTS IMPERVIOUS AREAS & REQUIRED L.I.D. AREAS North Site South Site Total Site mmklakl Area Multi lier Area Area (s.f.) (s.f.) (s.f.) Paved Areas 25,236 29,643 31 370 41 097 56,606 70,740 127,346 Building Areas 3 6,052 2 7,528 3 4,718 3 9,761 1 5 589 1 3 917 37,899 48,256 86,155 Sidewalks 5,476 5,572 3,317 4,913 3,468 6,475 830 426 13,091 17,386 30,477 Aggregate Impervious Area 107,5961 136,382 243,978 Area required to pass through bio-filter: 53,798 68,191 121,989 50% of impervious area Required area of permeablepavement: 14,152 17,685 31,837 (25% of paved area) Observations and Possible Compliance Options 1. The aggregate of the paved areas represents approximately 54% of the total impervious area in the norther portion of the site and approximately 52% of the total impervious area in the southern portion of the site. 2. It may be most efficient to simply divert all of the runoff from the paved areas to the respective bioswales. 3. A significant portion of the sidewalks will also drain onto the drive aisles and thus into to the bioswales 4. In the northern portion of the site, it is relatively easy to drain the east -west drive aisle, the eastern drive aisle, the clubhouse and a significant portion of the sidewalks into a bioswale along the east property line (an aggregate tributary area of approximately 38,375 s.f.), but it is more difficult to drain the western drive ai: virtually all of the buildings into the bioswale. This leaves a deficit of approximately 14,450 s.f. 5. In the southern portion of the site, a much larger portion of the impervious area drains toward the south perimeter of the site, and a potential bioswale. The tributary area could include all but approx. 7,470 s.f of paved area, approx. 9,350 s.f. of sidewalk, and approx. 23,610 s.f. of buildings, yielding a total tributary area of impervious surface of approx. 96,230 s.f. That tributary area exceeds the required tributary area by approx. 28,040 s.f. This more than offsets the diversion deficit from the northern portion of the site. 6. The required area of pourous or permeable pavement is 31,837 s.f. If this area is to be achieved through installation of pavers in parking areas, with the area of a typical parking stall that is suitable for pavers measuring 9' x 14' (126 s.f.), then 252 parking stalls would have to be surfaced with pavers. There are insufficient parking stalls within the project to accomplish the objective. 7. If pourous pavers are installed in each of the four entrance driveways, from the street to the first crosswalk, and throughout the length of the east drive aisle and the adjacent parking stalls in the northern portion of the site, the area of coverage would be approx. 33,000 s.f. This is probably the most appropriate location for the pavers, except for the fact that the distribution of pavers would be heavily weighted to the north portion of the site. EXISTINGNV ,� 1 CURB AND GUTTER, (TYP) \ \ \ \ /. 74 \ 8-UNIT BUILDING 24-UNIT BUILDING PROPOSED CURB AND GUTTER, (TYP) CG OWEN CONSULTING GROUP, INC. 3715 Shallow Pond Drive Phone: (970) 226-0264 Ft. Collins, CO 80528 larrycowen@comcast.net v CLUB HOUSE 77- 77 6-UNIT BUILDING SCALE: 1 "= 40'-0" _I_I_ 0 20' 40' --t �I I I 1 —4 I I —1 I Plroderickson PLANNERS/LANDSCAPE ARCHITECTS 1619 KELMSLEY C7. WINDSOR, CO 80550 deanne®TFGcolondo.com (970) 674-3323 o N U3 1 1 j = --4 M. TIMM DEVELOPMENT g BILL TIMM m Iui 233 EAST CARRILLO ST � If ( SANTA BARBARA cr w CA 93101 a / (805) 963-0358 Zz+ to / z LL o QO J / x a x W �� 0 Zo W a. = / .. ,, u z & 0 Lu x Wo > W Lu z °o �Z 0-0 04 i l ° D / ° 0 z A N 80' 120' 1i NORTH No. RevisiorVIssue Date =o 1 SHORTENED TRI. 5/13/13 09 ULn NO ZW o� PROJECT: SCALE: 1"=40'-0" z DATE: DRAWN BY: ZQ 5.8.13 DLK z Z SHEET W 1 7 O O OF rn x Mr. Marc Virata RE. Ridgewood Hills Residences Fourth Filing Major Amendment — Request for Variance May 7, 2013 Page 2 of 2 easements will be required, and these will be dedicated via the subdivision plat for the project. In light of the information presented here, we respectfully request that a variance be granted, allowing a reduced sight distance of 445 feet for the eastern driveway, where the governing sight triangle is based on an entering vehicle that would ultimately be turning left onto Avondale Road, and a reduced sight distance of 385 feet for the western driveway, where the governing sight triangle is based on an entering vehicle that would be turning right onto Avondale Road. We trust that you will concur with us that such a variance will in no way compromise the health, safety or welfare of motorists traveling on Avondale Road or those entering the road from the subject driveways. If you have questions or comments regarding this variance request, please contact me immediately. Thank you for your consideration of this request. Yours truly, Owen Consulting Larry C. Owen, cc: Mr. Bill Timm, M. Timm Development, Inc. CG OWEN CONSULTING GROUP, INC. May 7, 2013 City of Fort Collins Engineering Development Review 281 N. College Ave Fort Collins, CO 80522 Attention: Mr. Marc Virata Project File #: 12-390 RE: Ridgewood Hills Residences Fourth Filing Major Amendment, MJA 130003 Dear Marc, We are writing to request a variance from the requirements of Section 7.4.1.C.4 of the Larimer County Urban Area Street Standards regarding Corner or Intersection Sight Distances. The intersections that are the. subject of this letter are the two proposed driveways that will provide access to the northern portion of the referenced development from Avondale Road. Avondale Road is designated on the City of Fort Collins Master Street Plan as a 2- lane Collector street. At this time, the eastward extension of Avondale Road from Triangle Drive has not been constructed, however, it will be further extended as part of the proposed project, and it is expected, ultimately, to be extended through to an intersection with College Ave as part of the development of the Shenandoah Land property. Avondale Road carries a design speed of 40 mph. Section 7.4.1.C.4 of LCUASS requires that intersection sight distances be provided in accordance with Figure 7-16, which specifies a sight distance of 660 feet where a local street or driveway intersects a street with a design speed of 40 mph. This prescribed sight distance is based upon a design philosophy that allows for no slowing of an approaching vehicle on the through street, as a vehicle enters the street and accelerates to speed in a controlled manner. AASHTO has subsequently recognized that such a design philosophy is not realistic and no longer applies this philosophy as the basis for sight distance recommendations. The current edition of the AASHTO Policy on Geometric Design of Highways and Streets recommends an intersection sight distance of 445 feet for a passenger vehicle making a left turn from a stop onto a 2-lane through street with a design speed of 40 mph. This recommended distance is based on the equation d = 1.47 V tg, where tg = a time gap of 7.5 seconds. For right -turning vehicles, the time specified time gap is 6.5 seconds and the recommended sight distance is 385 feet. The attached exhibit shows the extent of sight distance triangles for the subject driveway intersections, based on the AASHTO criteria. As the exhibit shows, sight 3715 Shallow Pond Dr., Fort Collins, CO 80528 • Phone (970) 226-0264 Fax (970) 226-3 660