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Home My WebLink AboutREGISTRY RIDGE PUD, 2ND FILING - PRELIMINARY - 32-95D - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTPreliminary Drainage Report Registry Ridge P.U.D. Second Filing March 26, 1997 Page 6 Section A: Developed Hydrology Section B: Design of Inlets Section C: Design of Swales Northem Engineering Services, Inc. TABLE OF CONTENTS PAGE Al- A5 ............................................................ B1- B6 Cl- C3 Prelhninary Drainage Report Registry Ridge P.U.D. Second Filing March 26, 1997 Page 5 Northern Engineering Services, Inc. REFERENCES 1). Final Drainage Reno_, rt for Registry Ridge P U D_, Fort Collins, Colorado, Northern Engineering Services, Inc., June 24, 1996. 2.) Fossil Creek Drainage Basin Master Drainageway Planning Study, City Of Fort Collins, Simons, Li & Associates; Inc., August 1982. 3.) Storm Drainage Design Criteria and Construction Standards, City of Fort Collins, Colorado, May, 1984. 4.) Drainage Criteria Maunal, Urban Drainage and Flood Control District, Wright - McLaughlin Engineers, Denver, Colorado, March, 1969. IPreliminary Drainage Report Northern Engineering Services, Inc. Registry Ridge P.U.D. Second Filing I March 26, 1997 Page 4 V. EROSION CONTROL 5.1 Erosion Control 21an Permanent riprap will be provided at the outlet of all storm sewers. Grass -lined swales shall be seeded immediately upon completion with the permanent seed mix specified on the Grading Plan. Temporary sediment control consisting of straw bale dikes will be used in swales until permanent vegetation is established. Gravel filters will be required at all curb inlets and silt fencing installed adjacent to ponds and drainageways. See the Grading and Erosion Control Plan for additional information. VI. CONCLUSIONS 6.1 compliance with Standards All drainage analyses have been performed according to the City of Fort Collins Storm Drainage Design Criteria Manual (SDDCM) and the Urban Drainage and Flood Control District's Drainage Criteria Manual. fPreliminary Drainage Report Northern Engineering Services, Inc. Registry Ridge P.U.D. Second Filing March 26, 1997 Page 3 Criteria Manual,(SDDCM) and Storm Drainage Criteria Manual by the Urban Drainage and Flood Control District have been referenced for this Final Drainage Study. 4.3 Hydrologic Criteria The Rational Method has been used to estimate peak stormwater runoff within the I developed site. The initial 2-year and major 100-year design storms have been used in the evaluation of the proposed drainage system. Rainfall intensity data for the Rational Method has been taken from IDF curves and equations generated specifically for the Registry Ridge I P.U.D. site by the computer program "Watershed Modeling" by Eagle Point. Input of precipitation amounts have been taken from the NOAA Atlas 2, Volume III - Colorado. Compared to Figure 3-1 in the SDDCM, rainfall intensities generated for the Registry Ridge site were approximately 15% higher than intensities given in Figure 3-1. 4.4 Hydraulic Criteria The City of Fort Collins Storm Drainage Design Criteria has been referenced for all hydraulic calculations. In addition, the following computer programs have been utilized: • The computer program "UDINLET" has been used to analyze inlet capacities, • The computer program "Flowmaster" has been used to analyze the capacity of proposed swales, 4.5 Drainage Concept Detention is not a requirement within the Fossil Creek Major Drainage Basin although detention has been provided for the Second Filing in Pond 603, as part of the First Filing final design. Developed stormwater from the north side of Bon Homme Richard Drive will be conveyed through Storm Sewer Line 32 to Detention Pond 603. The proposed Storm Sewer Line 26 shown on the First Filing plans will be connected to Storm Sewer Line 32 thus eliminating Storm Sewer Line 26. Developed stormwater from the south side of Bon Homme Richard Drive will be conveyed through Storm Sewer Line 3 to Detention. Pond 603. A fifteen (15) foot curb inlet (Inlet 3) will be provided in addition to an overflow Swale at Design Point 3 (See Drainage Plan). During the 100-year event, stormwater will be conveyed to Pond 603 through both Storm Sewer Line 3 and the overflow Swale. Emergency overflows will also be provided for the other two (2) inlets on the north side of Bon Homme Richard Drive (Inlets' 1 & 2). IPreliminary Drainage Report Registry Ridge P.U.D. Second Filing I March 26, 1997 Page 2 Northern Engineering Services, Inc. I2.3 Irrigation Ditches and Reservoirs Lang Gulch is located approximately 300 feet south of the Second Filing. The City of Fort Collins has delineated the 100-year floodplain for Lang Gulch which is reflected on the Drainage and Grading Plans. There is also a proposed floodplain delineation on these plans I that reflects the proposed grading of Pond 603. There are no existing irrigation laterals on the site. III. HISTORIC DRAINAGE BASIN 3.1 Major Basin Description The site is located in the Fossil Creek Drainage Basin and is included in the report entitled Fossil Creek Drainage Basin Master Drainageway Planning Study, by Simons, Li & Associates, Inc., August, 1982. The SWMM model developed as part of the Master Study has been updated by Northern Engineering as part of the First Filing to reflect proposed developed conditions. I 3.2 Historic Drainage Patterns The site to the north of Bon Homme Richard Drive historically drains from west to east at slopes ranging from 1.24% to 1.36%. The site to the south of Bon Homme Richard Drive historically drains from north to south at slopes ranging from 3.84% to 8.86%. The majority of the Second Filing site is tributary to Lang Gulch (Developed Basins' 1- 3 and 403S, See Drainage Plan). Only a small portion of the Second Filing (located north of Bon Homme) is included in the First Filing Basins' 402D and 402L. Runoff from these small areas will be I conveyed to Pond 602 as shown on the First Filing Drainage Plan. IV. DEVELOPED DRAINAGE 4.1 DeveloWd Conditions Planned development for Registry Ridge P.U.D. Second Filing includes: 0 Multi Family Residential, I• Commercial, • new local drives, The downstream parcel of land, from the east side of Shield Street to the C&S Railroad tracks, is owned by Colorado Land Source Ltd. which is also the developer of Registry Ridge P.U.D.. 4.2 Design Criteria and References Drainage criteria outlined in both the City of Fort Collins Storm Drainage Design i Preliminary Drainage Report for Registry Ridge P.U.D. Second Filing I Fort Collins, Colorado March 26, 1997 I. INTRODUCTION 1.1 Objective To provide a preliminary drainage scheme for the proposed Registry Ridge I planned unit development, Second Filing, based on master drainageway planning and overall/ preliminary drainage concepts. The specific objective as related to this study is: 1. To adopt the drainage criteria contained in the Final Drainage Report for Registry Ridge P.U.D. First Filing, (Reference 1), I 1.2 Maiming and Surveying Topography of the site was provided to Northern Engineering Services by JR Engineering with a contour interval of one (1) foot. 1.3 Site Reconnaissance A site visit was conducted on Friday June 31, 1996 by the project engineer. Based on the topographic mapping, existing drainage basins and land use were confirmed as well as existing structures. The location and dimensions of existing culverts were verified as well as their condition and flow direction. II. SITE LOCATION AND DESCRIPTION 2.1 Site T &cation The site is located within the East Half of Section 15, Township 6 North, Range 69 I west of the 6th Principal Meridian in Fort Collins, Colorado. The project is bounded by Trilby Road on the north and Shields Street on the east. (See Vicinity Map). 2.2 Site Description Registry Ridge P.U.D. Second Filing is a total of approximately 19.850 acres, with 12.160 acres and 7.690 acres located north and south respectively of Bon Homme Richard I Drive. The site has historically been furrowed agricultural land and there are no existing structures. VICINITY MAP NARf'IONY_ ROAJL_..._ .._.-....-...-......_. _ ... _ . -... ---- -... FRONT RANGE u COMMUNITY Q COLLEGE >r 0 J RLP r Q T !tt n J �_ , ' 5�It <NOLLS SUB," OUT () O I 4V i Al MTN '✓ALt-El ACRE5 SUB �.. :. 7//7/ /.II 'TRILB,' ROAD _ .,r-IT, LIMIT 14 I5 I UGA BOUNDARI CITI LIMIT FA -I �I SCALE: I' •IIOW' 1 a 1 w � �t t O I �u I l I i i8 0) IN 0 ¢o 0 Z � W 8„ C' Z 9 s_ W� z 0 z NORTHERN March 26, 1997 City of Fort Collins Stormwater Utility 235 Mathews Fort Collins, Colorado 80522 RE: Registry Ridge P.U.D. Second Filing Fort Collins, Colorado Project Number: 9615-07 Dear Staff: Northern Engineering Services, Inc. is pleased to submit this Preliminary Drainage Report for Registry Ridge P.U.D. Second Filing for your review. This report was prepared in compliance with technical criteria set forth in the City of Fort Collins Storm Drainage Design Criteria and Construction Standards manual. If you should have any questions or comments as you review this report, please feel free to contact me at your convenience. Sincerely, NORTHERN —� 30325 Mary B. Wohnra VICES, INC. 420 SOUTH HOWES, SUITE 202, FORT (OLLINS, (OLORADO 80521, (970) 221-4158, FAX (970) 221-4159 Preliminary Drainage Report for Registry Ridge P.U.D. Second Filing Fort Collins, Colorado March 26, 1997 Prepared For: Colorado Land Source, LTD. 9085 East Mineral Circle, Suite 200 Englewood, Colorado 80112 Prepared By: Northern Engineering Services, Inc 420 S. Howes, Suite 202 Fan Collins, Colorado 80521 Phone:(970)221-4158 Project Number: 9615.07