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HomeMy WebLinkAboutDrainage Reports - 04/15/2016f Final Drainage Summary AUNITED CIVIL Design Group . Z 15 Matthews sheet Offices Fort Collins, CO City of Fort Collins Approved Plans Approved by: ��� Ytt Dft� Date: 4--1 �5 - I (o Prepared for: Scout Leasing, LLC 330 South College Avenue, Suite 300 Fort Collins, CO 80S24 April4, 2016 1501 Academy Ct. Ste. 203 Fort Collins, Colorado 80524 (970) 530-4044 UNITED CIVIL Design Group mc April 4, 2016 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 RE: 215 Matthews Street Offices Fort Collins, Colorado Project Number: U15007 Dear Staff: Drainage Summary 215 Matthews Street Offices Fort Collins, CO United Civil Design Group, LLC. is pleased to submit this Final Drainage Summary for the 215 Matthews Street Offices site in Fort Collins, Colorado. In general, this summary serves to document the stormwater impacts associated with the proposed project. Site Location and Project Description The 215 Matthews Street Offices development site (referred herein as "the site") is located in the southwest quarter of Section 12, Township 6 North, Range 69 West of the Sixth P.M., City of Fort Collins, Larimer County, Colorado. The site consists of approximately 7,000 square -feet (sf) and is bounded by Matthews Street on the east, a public alley on the west, and existing multifamily residential properties to the north and south. See the attached Drainage Plan for additional information. The planned development for the site will consist of the following: • The construction of multi -story, office building with a proposed footprint of approximately 4,130 sf (5,060 sf roof footprint) with an enclosed parking garage on the first floor. • The construction of utilities to support the proposed building including sanitary, water and storm drainage. • The construction of right-of-way improvements including curb and gutter, public sidewalk and landscaping. Existing Conditions Hydrology The site, which is located within the Old Town Basin, is approximately 7,000 sf in size and currently consists of an existing one-story residential building, gravel parking area, and landscape areas with an existing percent -imperviousness of approximately 31%. Storm runoff from the site currently drains towards Matthews Street where runoff is I U14012-Drainage5ummary-Final.doc UNITED CIVIL Drainage Summary Design Group uc 215 Matthews Street Offices ' Fort Collins, CO intercepted by existing curb and gutter which directs the runoff to the north to storm ' sewer inlets and piping located near Oak Street. Refer to Appendix A for additional information. ' Floodplain The site is not located within a FEMA or City -regulatory floodway or floodplain. ' Developed Conditions Hydrology The developed site will consist of approximately 6,060 square feet of impervious area including roof, pavement and sidewalk. This is an increase of approximately 2,994 square feet of impervious area. The following table summarizes the changes of the site from existing to proposed conditions. Refer to the Drainage Plan and Hydrology calculations for additional information. Comparison Summary Table Existing Proposed Site Site Overall Area (sf) 7,000 7,000 Roof (so 1,321 5,060 Concrete (sf) 703 1004 Gravel (sf) 627 0 Landscape (sf) 4,349 935 Total Impervious Area (sf) 2,651 6,064 % Imperviousness 31% 78% The drainage patterns for the proposed condition will remain largely unchanged from existing conditions in that the vast majority of the drainage from the site will be directed towards Matthews Street. It is anticipated that no additional drainage ' area will be directed towards the west and the public alley with the proposed development. Storm Sewer The proposed improvements do not require any proposed storm sewer. The site will be using raised bioretention planter boxes for water quality which will daylight at grade and therefore will not require a storm sewer system. The underdrain within Planter Box #3 (the southwest planter) is designed to drain the planter and drain the Swale from the west side of the planter through the planter. The area draining to the west side of planter is approximately 200 sf which corresponds to approximately 0.04 cfs in the 100-year event. Refer to Appendix C for the culvert calculation. 2 U24012-Dralnage5ummary-Final.doc UNITED CIVIL Drainage Summary A� design' Group us 21S Matthews Street Offices ' Fort Collins, CO Swales ' The drainage design incorporates drainage swales along the north and south sides of the site. The drainage swales were typically designed with maximum 4h:1v side slopes, ' Manning's n of 0.035, capacity to carry the 100-year flowrates plus 33%, and velocities below 5 feet per second. Refer to Appendix C for Swale capacity calculations and the Drainage Plan for locations of Swale sections analyzed. ' Detention and Water Quality Requirements The proposed improvements will increase the total impervious area less than 5,000 ' square feet from existing conditions; therefore, stormwater quantity detention is not required. ' The Udall Natural Area provides water quality treatment for 50% of the site; however, the City encourages additional water quality onsite. The development is proposing to provide additional water quality measures in the form of bioretention planter boxes that will collect approximately 3,815 square feet of the roof area prior to releasing to Matthews Street. ' Low Impact Development (LID) Requirements In February of 2013, City Council adopted the LID policy and criteria. The proposed ' development is required to meet the newly adopted criteria. Per the criteria, the site must: • Treat no less than 50% of any newly added impervious area using one or a ' combination of LID techniques. • Treat no less than 25% of any newly added pavement area using a permeable pavement. ' The following measures are being implemented with this proposed development: Bioretention Planters t. Basins A2-A3 and B2 (with 3,815 sf of impervious roof area) will be routed through bioretention planter boxes that will collect roof drainage from the ' building downspouts being designed with this project. The bioretention planters have average depths of 9-inches with an overall volume of 106 cubic feet which exceeds the minimum design requirements for the area. Refer to the Appendix ' for additional calculations. Permeable Pavers Due to the small amount of added pavement not covered by roof (approximately 850 sf), and per communication with City staff, this site is not being required to provide permeable pavers. In total, the development is proposing to collect and treat 3,815 sf (62.9%) of the overall 6,064 sf of impervious area developed with this project. In addition, the 3 U24022-Dralnage5ummary-final.doc UNITED CIVIL Drainage Summary ' Design Group LLe 215 Matthews Street Offices Fort Collins, CO site is also being designed with other various open landscaped areas and vegetated swales to provide additional water quality in addition to the areas being treated with bioretention. Four Step Process With the adoption of the USDCM, the City has also adopted the "Four Step Process" ' that is recommended in Volume 3 of the USDCM in selecting structural BMPs for the redeveloping urban areas. The following portions of this summary describe each step and how it has been utilized for this project: 1 Step 1— Employ Runoff Reduction Practices The objective of this step is to reduce runoff peaks and volumes and to employ the ' technique of "minimizing directly connected impervious areas" (MDCIA). This project accomplishes this by: ' • Routing roof flows through bioretention planter boxes and through vegetated swales to increase time of concentration, promote infiltration and provide water quality. Step 2 — Provide Water Quality Capture Volume (WQCV) The objective of providing WQCV is to reduce the sediment load and other pollutants that exit the site. For this project WQCV is provided within the Udall Natural Area, so ' no additional WQCV is required. However, the development is providing bioretention planter boxes; and therefore, additional WQCV in order to satisfy the LID requirements. Step 3 — Stabilize Drainageways ' The site is not adjacent or near a major drainageway; however, this project will pay stormwater development and stormwater utility fees which the City uses, in part, to ' maintain the stability of the City drainageway systems. Step 4 — Consider Need for Industrial and Commercial BMPs This step is generally considered for industrial and commercial sites. As this ' development is proposing a small office building, no specialized BMPs have been considered for this project. ' Standard Operating Procedures (SOPS) In order for physical stormwater Best Management Practices (BMPs) to be effective, proper maintenance is essential. Maintenance includes both routinely scheduled ' activities, as well as non -routine repairs that may be required after large storms, or as a result of other unforeseen problems. Standard Operating Procedures should clearly identify BMP maintenance responsibility. ' Identifying who is responsible for maintenance of BMPs and ensuring that an adequate ' budget is allocated for maintenance is critical to the long-term success of BMPs. Maintenance responsibility may be assigned either publicly or privately. For this project, the privately owned BMPs including the bioretention planters and vegetated 4 U14012-DrainageSummary-Final.doc AUNITED CIVIL Drainage Summary � Design Group uc 215 Matthews Street Offices Fort Collins, CO swales are to be maintained by the property owner, homeowner's association (HOA), or property manager. Erosion Control ' Erosion control, both temporary and permanent, is a vital part of any development project. For this project, the site disturbance will be less than 10,000 sf; therefore, comprehensive ' erosion control measures have been included within the Grading and Erosion Control Plan for the project. Refer to the Utility Plans, under separate cover, for additional information. Conclusions In conclusion, the drainage system proposed within this Drainage Summary provides adequate conveyance of the developed stormwater runoff from the proposed development to existing discharge locations and drainage systems. It should also be noted that with this summary and the corresponding design, every attempt has been made to minimize any negative impacts on the downstream receiving waters. With the incorporation of the LID techniques, the site will discharge a lower sediment load and less runoff. We understand that review by the City of Fort Collins is to assure general compliance with standardized criteria contained in the Fort Collins Stormwater Criteria Manual (FCSCM). This summary was prepared in compliance with technical criteria set forth in both the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual and the. FCSCM. If you should have any questions or comments as you review this drainage summary, please feel free to contact us at your convenience. Sincerely, Unitedooved Civil Design Group, LLC ".4 Kevin Brazelton, PE Engineering Manager APPENDICES APPENDIX A - Hydrology Computations APPENDIX B - LID Calculations APPENDIX C - Hydraulic Calculations APPENDIX D — Referenced Material APPENDIX E - Drainage Plan 5 U14012-Drainage5ummary-FinalAm APPENDIX A Hydrology Calculations 11 i, i� L u_ O +' 0 a a L L Ul 0 in 0 3 u N � C c� C (J Ln t T-4 0 N W. Y C W $ On Ln O O el tt 0 U O C 7 1' H n V r- V to cq co r! O 0 0 C O. E O u N y a N 0 7 o Off' cL O 00 N a E _ O n 4 V E =Q N � Q J CJ d > N N 0 0 0 `w m a° a gq t\ e IR m y Ch p O ey Q C N^ m O � V r QC ti O O1 00' O O a+ O ai O O (71 O) LJD :[t3 0 0 0 C Cc Q O c 1Np N m x O w o O h •'I N f\ O N N J O U N O n rL E x O N 4 O 0 O j E O c 3 � � U v N tC N C r•1 O v � O v � a v � a H L .0 U N 0 > O_ u N � O E o v c A y n � O N Q 41 N v Q 0 n � O V ca K v a Y O w E Ln cLn O QI C \ J a 3 y U U � �a N 7 O O1 a E 0 v c f0 M C Gl 'u N U O c 7 cc a w p V_ �6 (� v .� v •i lO V1 Q1 � 01 rl 10 N m If1 m Ol m O V U 0 0 0 O O a O U O of a V � b m (O m RI m Cf1 m m 9z ~ 2 N a °J a2 v1 ZJ O t0 .Z o m a g g o m m 6 w v n E M M M O O n O O ry GO M II Cq J a m a a � o. l7 3Q 'a n p N II Gv� II 8 N rvNj KNf N N N IN O _ � y rl rl '-I ri ei V1 jp O Q m �t QI N VI 01 GO « Vi O YU � 4N0 N � N N Vnf N � �� o000000� g 0 0 0 0 0 N g w o a a a omm o F a N N c N C n L O p q 00 ~ m O ryN « IO �a W G a 0 E N 0 0 w m i c m K O N A L � y � N L V C ti 0 O V� O Y N t � a E ,0t c n n > CI N w a o C V O O v� a E o aE a a h v a Y 2 u a v o EO O O T a 3 O — S2 k V C) C N N V O N C m Q: to O 3 v° Cl vi C cm C u Ln t r4 O N I.I. C 1Y N pi C f0 L p 0 0� F�0- O J Y ^ y U L G 4), ) v > > } j } } u � m t �avo�n�ry -.r F o .-i000000 LL ,� aooeov?v,.� G C E P a N C C A Oa � N L H 0000000 C ^ J K E N oL �y Vl V1 O O O O G J m m m m N N O Ql 01 Ol Qt m Ot m Q1 N V O 0 0 0 0 0 0 0 A O ,O 0 C G V- 6 O O 0 0 C N ¢ d a ¢ 0 0 0 0 0 0 0 oN 0 6 0 0 0 0 0 0 rQ C bo N ti N M ti N M c r G m a a a m w w o N m c. m N C N O 42 O ti w w a QQQmmm0 N X O p t i 000 � 6 O u t 2 � yQ N !Ctl n O h O u � C ,uQ e i 5 e it y o .e y E 0 C v O C td GJ J � a O 2� F- 71 .5 N e N U �� [� Y z 5 _ � h \ M u iK j 0 V y U I v v rn rn m m r� m W W N DA h m m H N N •-1 N N rl lD r6 C7 O O 0 0 0 0 0 6 6 4 L V Y h c}w wi} 14 d cr N N O O O O O O a V O o O O O O O O O G Lf) Y) L,) L n = m m m m m m m m a ai ai ai ai m 6 a C 0 00 01 vl Ln 0n Ln vl u1 K C N N N N N N N N C_ m �O r, 0 O 0 00 rl O O g 00 00 .0 vmi V 0 O 14 14 O .4 14 O d O V ',k in M O O N 0 0 0 C U V t0 m m to m m m 7 O O O O O O O O K m = C 0 N Ln Ln v v n Ln Ln LL �, iY°- o F v L N O O O O O O O e o 0 0 0 0 0 0 0 .d) W d 0 V, C N C N •N f0 m a a a m m m o m w v c O x W 1 A t APPENDIX B LID Calculations ' 215 Matthews Street Offices Water quality UNITED CIVIL Fort Collins, Colorado ANNDesign Group Low Impact Development (LID) Treatment Areas Basin Proposed Impervious Area (sf) LID Treatment Area Treated (sf) % of Site Treated Individual Basins Basin Al 499 None 0 0% Basin A2 1,284 Bioretention 1,284 21% Basin A3 1,259 Bioretention 1,259 21% Basin B1 505 None 0 0% Basin B2 1,272 Bioretention 1,272 21% Basin 63 1,245 None 0 0% Total Site 6,064 3,815 1 63% Calculations by: KR8 Date: 111812016 C: J United Civill Dropbox�Projects 1 U15007 - 215 Mathews I Drainage �Hydrology] U15007-Runoff.xlsx Design Procedure Form: Rain Garden (RG) Sheet 1 of 2 Designor. KRB Company: United Civil Design Group Date: October 14. 2015 Project: 215 Matthews Street Location: Fort Collins 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area. I, I, = 90.0 % (100% 0 all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = I,/100) = 0.900 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.32 watershed inches (WQCV= 0.8 - (0.91• 13- 1.19' i2+ 0.78 - 1) D) Contributing Watershed Area (including rain garden area) Area = 3.815 sq ft E) Water Quality Capture Volume (WQCV) Design Volume Vwocv = 102 cu it Vol = (WQCV / 12)' Area F) For Watersheds Outside of the Denver Region, Depth of de = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region. VwOCV OTHER = cu it Water Quality Capture volume (WOCV) Design volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWOOV USER - cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth 02-inch maximum) Dwocv = 9 in B) Rain Garden Side Slopes (Z - 4 min., hortz. dist per unit vertical) Z = 0.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area Am„ - 68 sq ft D) Actual Flat Surface Area A, .j = 141 sq ft E) Area at Design Depth (Top Surface Area) AT.. = 141 sq ft F) Rain Garden Total Volume VT- 106 cu ft (VT- ((AT. ` A�) / 2) ' Depth) 3. Growing Media Choose One n 18" Rain Garden Growing Media Q Other (Explain): 4. Underdrain System — Qlpnse tyre * YES A) Are underdmins provided? p NO B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y= it Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol,, - NIA cu it id) Orifice Diameter, 3/8" Minimum Du = NIA in 1,10-BMP_0.03.xism, RG 10/14/2015, 301 PM Design Procedure Form: Rain Garden (RG) Sheet 2 of 2 Designer: KRB Company: United Civil Design Group Date: October 14, 2015 Project: 215 Matthews Street Location: Fort Collins 5. Impermeable Geomembmne Liner and Geolextile Separator Fabric — Choose r»e — (D YES A) Is an impermeable liner provided due to proximity Q NO 01 structures or groundwater contamination? 6. Inlet l Outlet Control Choose One-- Q Sheet Flow- No Energy Olsslpatlan Required A) Inlet Control Q Concentrated Flow- Energy Disslpadon Provided — C7xr+ae Lbm . 7. Vegetation Q Seed (Plan For frequent weed Control) QQ Plantings Q Sand Grown or Other High Infiltration Sod 8. Imgation Choose One Q YES A) Will the ram garden be imgated7 NO Notes II UD-BMP_v3.03.x1sm, RG 10l1412015, 3:01 PM APPENDIX C Hydraulic Calculations Culvert Report ' Hydraf low Express Extension for Autodesk®AutoCAD® Civil 3D® by Autodesk, Inc. Monday, Jan 18 201 Planter #3 Underdrain Invert Elev Dn (ft) = 81.26 Calculations Pipe Length (ft) = 10.83 Qmin (cfs) = 0.04 'Slope (%) = 1.48 Qmax (cfs) = 0.19 Invert Elev Up (ft) = 81.42 Tailwater Elev (ft) _ (dc+D)/2 Rise (in) = 6.0 ' Shape = Circular Highlighted Span (in) = 6.0 Qtotal (cfs) = 0.04 No. Barrels = 1 Qpipe (cfs) = 0.04 ' n-Value = 0.012 Qovertop (cfs) = 0.00 Culvert Type = Circular Concrete Veloc Dn (ft/s) = 0.33 Entrance = Square edge w/headwall (C) Veloc Up (ft/s) = 0.99 'Culvert Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 HGL Dn (ft) = 81,56 HGL Up (ft) = 81.55 'Embankment Top Elevation (ft) = 83.60 Hw Elev (ft) Hw/D (ft) = 81.57 = 0.31 Top Width (ft) = 10.50 Flow Regime = Outlet Control ' Crest Width (ft) = 6.00 'he underdrain within Planter Box #3 will also drain approximately 200 s lest of the planter (or approximately 21% of Basin Al). The calculation > based on 21 % of the total flowrate of Basin Al during the 100-year !vent. II �J I Channel Report ' Hydraf low Express Extension for Autodesk®AutoCAD® Civil 3D® by Autodesk, Inc North Swale ' User -defined Highlighted Invert Elev (ft) = 79.24 Depth (ft) 'Slope (%) = 1.45 Q (cfs) N-Value = 0.035 Area (sqft) Velocity (ft/s) 'Calculations Wetted Perim (ft) Compute by: Known Q Crit Depth, Yc (ft) Known Q (cfs) = 1.01 Top Width (ft) ' EGL (ft) (Sta, El, n)-(Sta, El, n)... ( 0,00, 79,89) -(0 65, 79.89, 0,025)-(3.53, 79.24, 0.035)-(5.35, 79.75, 0.035)-(8.13, 79.80, 0.025) Flowrate includes all of Basin B 100-year flowrates plus ' an additional 33% per Fort Collins addendum to Urban Drainage Section 4.1.1.5. ' Elev (ft) Section t 1 -I V 1 L 3 4 O O t Sta (ft) = 0.39 = 1.010 = 0.61 = 1.66 = 3.22 = 0.34 = 3.12 = 0.43 O O Monday, Jan 18 201 Depth (ft) 0.76 0.51 0.26 -0.24 Channel Report ' Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3138 by Autodesk, Inc South Swale User -defined Highlighted Invert Elev (ft) = 79.35 Depth (ft) 'Slope (%) = 1.00 Q (Cfs) N-Value = 0.025 Area (sqft) Velocity (ft/s) 'Calculations Wetted Perim (ft) Compute by: Known Q Crit Depth, Yc (ft) Known Q (cfs) = 1.24 Top Width (ft) ' EGL (ft) (Sta, El, n)-(Sta, El, n)... ( 0.00, 80.02)-(1.98, 80.02, 0.025)-(3.82, 79.35, 0,025)-(6.82, 80.21, 0.025)-(8.13, 80.20, 0.025) ' IFlowrate includes all of Basin A and Basin OS1 100- �year flowrates plus an additional 33% per Fort Collins laddendum to Urban Drainage Section 4.1.1.5. Elev (ft) Section 78.50 ' 1 0 1 2 3 4 ' Sta (ft) Thursday, Jan 28 2016 = 0.44 = 1.240 = 0.60 = 2.05 = 2.88 = 0.40 = 2.74 = 0.51 5 6 7 8 9 10 Depth (ft) 1.65 1.15 0.65 0.15 -0.35 WIVY APPENDIX D Referenced Material USDA United States Department of Agriculture MRCS Natural Resources Conservation Service A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Larimer County Area, Colorado 215 Matthews Street May 14, 2015 No Text O O 8 W m C C 00 -Qo (Ot�� L N ° N E p m m m 3 O p Cp _N �_ m p L a N N J C O (Cp V U 3 mZ m N j 0 N �Qp1 y O. pE 8m y4u�£ NW-0o —0 aZ mvv `co ammE ac mmN 0 d m-c m� t 2 dC7 of m J� ov a Q ££ E m- N i> U L 3 to a0)Eo a c�a °a��2 Z �N N v Lod O am a N a.Eai £ y w Ti£gcJ CL m E m amo- m N Cl)am°i mN NNN o aa3Nm £m3c Qa ry0 E �°c ;O m 0Nm ILL o m ao E O am �.9 oNn mE�S Z O N N O C N m 0n m Q a°°a n w o> a m m c Z0 .-0°mm a E Eo , 1a ,ma m E °m rn Z 'o c m~ a C m J £ 3 m m a m a O m t c m ° c J o c c m Z t n �8 �,E �cnQ, EEmc �o �° y om m EyyM dm `o-m oam a.o a.N Z� n m La am C ,�> U E J T m m C r N E m` a$ w m m a.0 9c a� 8 a> Z E m w ° n o L m E N m- m a) p m 8 m O N a- L O J m p L E m F- ?i w E n 8 a E N 3 U i$ v¢ c� H£ c9i rn c9i `o o �v 8 .E m N = m a N y c N N R gT C = = N a a = m d? B o r C r 2 g 'm E 3 0' Of c a Md c Om m W J LL = 8 Q 0 N 0 Q 0 y = >>ry n y a J d a. av 3 Q 8 o W n g a o U °m `d a n< w co U U 0 0 m Ci in in m o a c16 It m a '0 Custom Soil Resource Report Map Unit Legend Larlmer County Area, Colorado (C0644) Map Unit Symbol Map Unit Name Acres In A01 Percent of A01 35 Fort Collins loam, 0 to 3 percent slopes 7.6 25.3% 94 Satanta loam, 0 to 1 percent slopes 22.4 74.7% Totals for Area of Interest 30.0 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If 10 Custom Soil Resource Report intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. ' Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. ' Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the ' detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. ' Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. ' A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example. ' An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha - Beta association, 0 to 2 percent slopes, is an example. ' An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of ' the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. ' Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. 11 ' Custom Soil Resource Report ' Larimer County Area, Colorado t35—Fort Collins loam, 0 to 3 percent slopes Map Unit Setting ' National map unit symbol. 2tlnc Elevation: 4,020 to 6,730 feet Mean annual precipitation: 14 to 16 inches ' Mean annual air temperature: 46 to 48 degrees F Frost -free period. 143 to 154 days Farmland classification: Prime farmland if irrigated ' Map Unit Composition Fort collins and similar soils: 85 percent Estimates are based on observations, descriptions, and transacts of the mapunit. ' Description of Fort Collins Setting ' Landform: Interfluves Down -slope shape: Linear Across -slope shape: Linear ' Parent material: Pleistocene or older alluvium derived from igneous, metamorphic and sedimentary rock and/or eolian deposits Typical profile Ap - 0 to 4 inches: loam Bt1 - 4 to 9 inches: clay loam Bt2 - 9 to 16 inches: clay loam Bk1 - 16 to 29 inches: loam Bk2 - 29 to 80 inches: loam Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding. None Calcium carbonate, maximum in profile: 12 percent Salinity, maximum in profile: Nonsaline (0.1 to 1.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 0.5 Available water storage in profile: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 4c Hydrologic Soil Group: C Ecological site: Loamy plains (R067BY002CO) 12 Custom Soil Resource Report 1 94--Satanta loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol. jpyc Elevation: 4,800 to 5,600 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost -free period. 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Satanta and similar soils: 85 percent Estimates are based on observations, descriptions, and transacts of the mapunit. Description of Satanta Setting Landform: Terraces Landform position (three-dimensional): Side slope, tread Down -slope shape: Linear Across -slope shape: Linear Parent material. Mixed alluvium and/or eolian deposits Typical profile H1 - 0 to 12 inches: loam H2 - 12 to 18 inches: loam, clay loam, sandy clay loam H2 - 12 to 18 inches: loam, clay loam, fine sandy loam H2 - 12 to 18 inches: H3 - 18 to 60 inches: H3 - 18 to 60 inches: H3 - 18 to 60 inches: Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: Very high (about 26.4 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: B 13 GEOTECHNICAL SUBSURFACE EXPLORATION REPORT ' PROPOSED OFFICE BUILDING 215 MATTHEWS STREET FORT COLLINS, COLORADO Prepared By: SOILOGIC, Inc. Job Number: 15-1056 April 7, 2015 SOj LOGIC Geotechnical Subsurface Exploration Report Proposed Office Building 215 Matthews Street Fort Collins, Colorado Soilogic # 15-1056 10 order to maintain flooring product manufacturer warranties. A vapor barrier would help reduce the transmission of moisture through the floor slabs. However, the unilateral moisture release caused by placing concrete on an impermeable surface can increase slab curl. The amount of slab curl can be reduced by careful selection of an appropriate concrete mix. Slab curl cannot be eliminated. We recommend the owner, architect and flooring contractor consider the performance of the slabs in conjunction with the proposed flooring products to help determine if a vapor barrier will be required and where best to position the vapor barrier in relation to the floor slab. Additional guidance and recommendations concerning slab -on -grade design can be found in American Concrete Institute (ACI) section 302. Pavements Subgrades At this time, we understand permeable pavements may be utilized for the site drive and/or parking areas. Permeable pavement subgrades should be developed as outlined in the "Foundation Bearing and Site Development" portion of this report. Care should be taken to avoid densification of permeable pavement subgrade soils prior to placement of the overlying system. To complete the percolation test for aid in the design, three (3) eight -inch diameter and 36-inch deep percolation test holes were completed at each deep boring location. An average percolation rate of 57 minutes per inch was established in the near surface site soils and could be used in design. With the recommended overexcavation/backfill procedures to develop finish foundation bearing levels for the proposed building, it is our opinion a Partial of Full -Infiltration section could be used for this site. The near surface site lean clay is fine graded, such that a filter fabric should be employed at the clay/filter media interface. Minimum light and heavy-duty structural permeable pavement section designs are outlined below in Table I. Geotechnical Subsurface Exploration Report Proposed Office Building 215 Matthews Street Fort Collins, Colorado Soilogic # 15-1056 11 Table I —Permeable Pavement Section Design Classification Light -Duty Heavy -Duty Roadway Private Drive/Parking Private Drive/Parking Design Structural Number (2.42) (3.08) Option A — Permeable Pavement Surface Paver (SF Rima) 3.15" (0.40/inch) 3.15" (0.40/inch) Storage Media *6" (0.11/inch) *I I" (0.11/inch) Filter Media 6" (0.11/inch) 6" (0.11/inch) (Structural Number) (2.58) (3.13) * The storage media thickness outlined above is from a structural support perspective only for light -duty pavements. Greater thicknesses may be required based on storage water calculations and minimum requirements provided by the system manufacturer. Light -duty pavements could be considered for light vehicle parking areas. Heavy- duty pavements should be considered for access drives and other areas of the site expected to receive heavy trash or delivery truck traffic. We recommend permeable pavement filter and storage media be adjusted to a workable moisture content and compacted to at least 75% of the material's relative density. Corrosive Soil Characteristics Water-soluble sulfates (WSS) tests were completed on two (2) selected soil samples obtained from the site to help evaluate corrosive soil characteristics with respect to buried concrete. A corrosive soil characteristics outline is included with this report. The WSS tests fall within the "negligible" and "moderate" classification with respect to the severity of the sulfate environment. Type II cement should be used for project concrete exposed to soils with a "moderate" classification. If Type II cement is not available, care should be taken to thoroughly consolidate concrete exposed to the site soils. A maximum water/cement ratio of 0.50 is recommended for "moderate" severity. In addition, consideration could be given to utilizing air -entrained concrete exposed to the site soils, APPENDIX E Drainage Plan N LOLSSO,. I' OI ENDED REDERFAME ON."'IGI ONE NORTI SYW1E SECIFONR CEF.DN"ImI0Ea SMUFM sNMLE mcnoR LEGEND ER EMnI� «MaEh a sn R. 7—r-T\ N -- EN�NG. VEMENTS,RINI asn:oa .aBNER UNITED CIVIL N— BOOSTING FENCE A DISTINGELELTIC Design Group EXISTING BUILDERS m— ELI GVERHFAO ELECTRIC EASONG PROPEWY LINE FASTING CABLE EFUME Civil Engineering a cOTBanisg ME UNITS OF DISTURBANCE - —J0102 - PASTING CONTOUR PrroPosEDCOMMUR 1502 Acetlamy C1. X B.dw ceslcGAnox BtB. 2➢3 Fort Collins, CO 80524 zIa oPF (910) 530d044 F C Im vR RUNOFF coEFF vrvw.unitFMcivilmm BURUN,EAIACREI eg&� Its sla ® I uweaMwRv DESIGN POINT [°fY a DENS O $ E NOTES g;,j p a RR UTLDIFSAS SIN)WNMEMgCR]FD RCLgIgNG 10 THE BEST IHFORNITMAVAUBLE TO THE ENGINEER2. PLTATTAL AI AND THE IVBLEE STANDARD OPEMTNNGGRPRCCEDU ETENTUM ES AS HTTERSOYM IN DEVELOA ENDIVE EMBYTEEMROPFOR3 MATTHE FIXLpV D S ACRE ENS B C if aQi SISEET0FFICES. - F-F%P m_ S In k f j Go V/ ~ Lij L.U.J O LL z z LL O -j U a LU W Z DRAINAGE SUMMARY Q Q awn cenan point ! w a nas in woo fC+l fNl WON HMIs Ex-1 EY1 M16 31% O.a 0.59 an 0.9s propDF.411I Rl RI 002 4B% 0,61 0]] 0.05 s17 /S .V 0.03 90K 095 I O.W py9 /3 ei 0.03 9WE 095 S.So 0Se 0.H Bl Bl 0.02 48% 0.61 O.D 0.01 O.11 B3 B2 O.a3 90% 095 I.W OAB 0.29 83 03 0.03 2 0.95 1.Ea O.BB 0.28 O51 051 001 30% 0.39 OA9 0.04 0.28 City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: Dt/ 8giv Date CHECKED BY: filer a TutePater NIB!) Date CHECKED BY: 8larmraw D agr EI CHECKED BY: Parts a aeE4eatlm Date CHECKED BY: nom sagomee Oate CHECKED BY: BB9➢mmr•W Pku Date_ 2 LO