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HomeMy WebLinkAboutJEFFERSON & LINDEN RESTAURANT - FDP - FDP170002 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTJanuary 18, 2017 FINAL DRAINAGE AND EROSION CONTROL REPORT FOR JEFFERSON AND LINDEN RESTAURANT Fort Collins, Colorado Prepared for: Blue Ocean Enterprises 401 W. Mountain Ave. Fort Collins, CO 805211 Prepared by: 200 South College Avenue, Suite 10 Fort Collins, Colorado 80524 Phone: 970.221.4158 Fax: 970.221.4159 www.northernengineering.com Project Number: 838-014  This Drainage Report is consciously provided as a PDF. Please consider the environment before printing this document in its entirety. When a hard copy is absolutely necessary, we recommend double-sided printing. January 18, 2017 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 RE: Final Drainage and Erosion Control Report for JEFFERSON AND LINDEN RESTAURANT Dear Staff: Northern Engineering is pleased to submit this Final Drainage and Erosion Control Report for your review. This report accompanies the Final Plan submittal for the proposed Jefferson and Linden Restaurant Project. This report has been prepared in accordance to Fort Collins Stormwater Criteria Manual (FCSCM), and serves to document the stormwater impacts associated with the proposed project. We understand that review by the City is to assure general compliance with standardized criteria contained in the FCSCM. If you should have any questions as you review this report, please feel free to contact us. Sincerely, NORTHERN ENGINEERING SERVICES, INC. Aaron Cvar, PhD, PE Senior Project Engineer Jefferson and Linden Restaurant Final Drainage Report TABLE OF CONTENTS I. GENERAL LOCATION AND DESCRIPTION ................................................................... 1 A. Location ............................................................................................................................................. 1 B. Description of Property ..................................................................................................................... 2 C. Floodplain.......................................................................................................................................... 3 II. DRAINAGE BASINS AND SUB-BASINS ....................................................................... 4 A. Major Basin Description .................................................................................................................... 4 B. Sub-Basin Description ....................................................................................................................... 5 III. DRAINAGE DESIGN CRITERIA ................................................................................... 5 A. Regulations........................................................................................................................................ 5 B. Four Step Process .............................................................................................................................. 5 C. Development Criteria Reference and Constraints ............................................................................ 6 D. Hydrological Criteria ......................................................................................................................... 6 E. Hydraulic Criteria .............................................................................................................................. 6 F. Modifications of Criteria ................................................................................................................... 6 IV. DRAINAGE FACILITY DESIGN .................................................................................... 6 A. General Concept ............................................................................................................................... 6 B. Specific Details .................................................................................................................................. 7 V. CONCLUSIONS ........................................................................................................ 7 A. Compliance with Standards .............................................................................................................. 7 B. Drainage Concept .............................................................................................................................. 8 APPENDICES: APPENDIX A.1 - Hydrologic Computations APPENDIX A.2 - Hydraulic Computations APPENDIX B - USDA Soils Information APPENDIX C - LID Design Information APPENDIX D - Master Basin Modeling Summary APPENDIX E - Erosion Control Report MAP POCKET: Drainage Exhibit Jefferson and Linden Restaurant Final Drainage Report LIST OF FIGURES: Figure 1 – Aerial Photograph ................................................................................................ 2 Figure 2– Proposed Site Plan ................................................................................................ 3 Figure 3 – Existing Floodplains ............................................................................................. 4 MAP POCKET: Proposed Drainage Exhibit Jefferson and Linden Restaurant Final Drainage Report 1 I. GENERAL LOCATION AND DESCRIPTION A. Location 1. Vicinity Map 2. The project site is located in Block 7 of Fort Collins, which is within the northwest quarter of Section 12, Township 7 North, Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. 3. The project site is located just north of the intersection of Linden Street and Jefferson Street. 4. The project site lies within the Old Town Basin, and would typically detain and release at the Historic 2-year release rate. However, based on master basin modeling completed with this report, and newly constructed improvements to storm infrastructure within Jefferson Street, detention is not required for the site. Please see further discussion in Section II.A, below. Additionally, the site still must provide water quality treatment. Water quality treatment methods are described in further detail below. 5. As this is an infill site, the area surrounding the site is fully developed. Jefferson and Linden Restaurant Final Drainage Report 2 6. No offsite flows enter the site. B. Description of Property 1. The development area is roughly 0.57 net acres. Figure 1 – Aerial Photograph 2. The subject property is currently a park. Existing ground slopes are mild to moderate (i.e., 1 - 6±%) through the interior of the property. General topography slopes from northwest to southeast. 3. According to the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Soil Survey website: http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx, the site consists of Paoli Fine Sandy Loam, which falls into Hydrologic Soil Group A. 4. The proposed project site plan is composed of the development of a restaurant. Parking for the restaurant will be provided offsite. Associated landscaping, water and sewer lines, and other improvements will be constructed with the development. Onsite water quality treatment is proposed and will consist of several features which are discussed in Section IV, below. Project Site Jefferson and Linden Restaurant Final Drainage Report 3 Figure 2– Proposed Site Plan 5. There are no known irrigation laterals crossing the site. 6. The proposed land use is a restaurant. C. Floodplain 1. The project site is not encroached by any FEMA or City designated 100-year floodplain. Jefferson and Linden Restaurant Final Drainage Report 4 Figure 3 –Area Floodplain Mapping II. DRAINAGE BASINS AND SUB-BASINS A. Major Basin Description 1. The project site lies within the Old Town Basin. In this basin, typical detention requirements are to detain the difference between the 100-year developed inflow rate and the historic 2-year release rate. We have been in discussion with City Staff on the possibility of releasing all developed site drainage undetained into the newly constructed storm system in Jefferson Street. The site is located within the study area identified in the “Downtown River District (DTRD) Final Design Report”, by Ayres Associates, dated February 2012. The site lies within several master plan sub- basins, specifically Basins 110, 111, 206, and 210, as shown in DTRD Plan noted as “Exhibit B-Future Development Map for DTRD Area” (Provided in Appendix E). As discussed with City Staff, this project would take portions of Basins 110, 111, and 210, with a sum total of 0.40 acre, and incorporate these portions into Basin 206. In doing so, we will be routing the project site into the recently completed Downtown River District “Storm Line B”. Thus, we are introducing an additional 0.40 acres of undetained drainage area into this system. Based on the modeling summary provided in Appendix E, the site will not be required to detain developed flows. Briefly put, the modeling we have completed adequately addresses any potential concerns related to storm line capacity in the recently completed Downtown River District “Storm Line B”. The study shows there is negligible impact due to the proposed minor adjustments to master plan Basins 110, 111, 206, and 210. Project Site Jefferson and Linden Restaurant Final Drainage Report 5 B. Sub-Basin Description 1. The subject property historically drains overland from northwest to southeast. Runoff from the majority of the site has historically been collected in the existing storm systems within Linden Street and Jefferson Street. 2. A more detailed description of the project drainage patterns is provided below. III. DRAINAGE DESIGN CRITERIA A. Regulations There are no optional provisions outside of the FCSCM proposed with the proposed project. B. Four Step Process The overall stormwater management strategy employed with the proposed project utilizes the “Four Step Process” to minimize adverse impacts of urbanization on receiving waters. The following is a description of how the proposed development has incorporated each step. Step 1 – Employ Runoff Reduction Practices Several techniques have been utilized with the proposed development to facilitate the reduction of runoff peaks, volumes, and pollutant loads as the site is developed from the current use by implementing multiple Low Impact Development (LID) strategies including: Conserving existing amenities in the site including existing vegetated areas and mature trees. Providing vegetated landscape islands in the parking lot to reduce the overall impervious area and to minimize directly connected impervious areas (MDCIA). Step 2 – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with Slow Release The efforts taken in Step 1 will facilitate the reduction of runoff; however, urban development of this intensity will still generate stormwater runoff that will require additional BMPs and water quality. The majority of stormwater runoff from the site will ultimately be intercepted and treated using extended detention methods prior to exiting the site. Step 3 – Stabilize Drainageways There are no major drainageways within the subject property. While this step may not seem applicable to proposed development, the project indirectly helps achieve stabilized drainageways nonetheless. By providing water quality treatment, where none previously existed, sediment with erosion potential is removed from downstream drainageway systems. Furthermore, this project will pay one-time stormwater development fees, as well as ongoing monthly stormwater utility fees, both of which help achieve City-wide drainageway stability. Step 4 – Implement Site Specific and Other Source Control BMPs. The proposed project will improve upon site specific source controls compared to historic conditions: The proposed development will provide LID and water quality treatment; thus, eliminating sources of potential pollution previously left exposed to weathering and runoff processes. Jefferson and Linden Restaurant Final Drainage Report 6 C. Development Criteria Reference and Constraints The subject property is surrounded by currently developed properties. Thus, several constraints have been identified during the course of this analysis that will impact the proposed drainage system including: Existing elevations along the property lines will generally be maintained. As previously mentioned, overall drainage patterns of the existing site will be maintained. Elevations of existing downstream facilities that the subject property will release to will be maintained. D. Hydrological Criteria 1. The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in Figure RA-16 of the FCSCM, serve as the source for all hydrologic computations associated with the proposed development. Tabulated data contained in Table RA-7 has been utilized for Rational Method runoff calculations. 2. The Rational Method has been employed to compute stormwater runoff utilizing coefficients contained in Tables RO-11 and RO-12 of the FCSCM. 3. Three separate design storms have been utilized to address distinct drainage scenarios. A fourth design storm has also been computed for comparison purposes. The first design storm considered is the 80th percentile rain event, which has been employed to design the project’s water quality features. The second event analyzed is the “Minor,” or “Initial” Storm, which has a 2-year recurrence interval. The third event considered is the “Major Storm,” which has a 100-year recurrence interval. The fourth storm computed, for comparison purposes only, is the 10-year event. 4. No other assumptions or calculation methods have been used with this development that are not referenced by current City of Fort Collins criteria. E. Hydraulic Criteria 1. As previously noted, the subject property maintains historic drainage patterns. 2. All drainage facilities proposed with the project are designed in accordance with criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual. 3. As stated above, the proposed project does not propose to modify any natural drainageways. F. Modifications of Criteria 1. The proposed development is not requesting any modifications to criteria at this time. IV. DRAINAGE FACILITY DESIGN A. General Concept 1. The main objectives of the project drainage design are to maintain existing drainage patterns, and to ensure no adverse impacts to any adjacent properties. 2. Onsite water quality treatment will be provided, and is discussed further below. 3. Drainage patterns anticipated for drainage basins shown in the Drainage Exhibit are Jefferson and Linden Restaurant Final Drainage Report 7 described below. Drainage basins have been defined for preliminary design purposes and are subject to change at Final design; however, general drainage patterns and concepts are not expected to be significantly altered. Basin 1 Basin 1 consists of landscaped areas, and will generally drain via sheet flow across the existing sidewalk running along the north side of Jefferson Street in to the adjacent curb and gutter of Jefferson Street. Basin 2 Basin 2 will consist of landscaped areas, rooftop, and a decorative concrete patio area. Storm runoff will be directed primarily via roof piping systems and surface flow into an underground LID treatment chamber system as shown on the Drainage Exhibit. Please see further discussion of water quality and LID features in Section IV.B, below. Basin 3 Basin 3 consists of a small strip of landscaped area along the north side of the proposed building that will sheet flow onto the neighboring railroad right of way. A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report. B. Specific Details 1. The prime LID feature that has been incorporated in the design of the proposed site consists of an underground LID chamber system. The majority of the proposed impervious area (mainly rooftop area, and decorative concrete patio area) will be conveyed into the proposed underground LID chamber system located under the decorative concrete patio at the southeast corner of the site. This chamber system will outfall to the newly improved storm line system within Jefferson Street. 2. Current City of Fort Collins code minimums are being met with the current site plan as summarized in the LID Design information provided in Appendix C. 3. The drainage features associated with the proposed project are all private facilities, located on private property, with the the site outfall, which will be a storm line tie-in within Jefferson Street Street Right of Way. V. CONCLUSIONS A. Compliance with Standards 1. The drainage design proposed with the proposed project complies with the City of Fort Collins’ Stormwater Criteria Manual. 2. The drainage design proposed with this project complies with requirements for the Old Town Basin. As noted in Section II.A, the site will not detain flows based on modeling submitted for this project. 3. The drainage plan and stormwater management measures proposed with the proposed development are compliant with all applicable State and Federal regulations governing stormwater discharge. Jefferson and Linden Restaurant Final Drainage Report 8 B. Drainage Concept 1. The drainage design proposed with this project will effectively limit any potential damage associated with its stormwater runoff by providing detention and water quality mitigation features. 2. The drainage concept for the proposed development is consistent with requirements for the Old Town Basin. Jefferson and Linden Restaurant Final Drainage Report 9 References 1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No. 174, 2011, and referenced in Section 26-500 (c) of the City of Fort Collins Municipal Code. 2. Larimer County Urban Area Street Standards, Adopted January 2, 2001, Repealed and Reenacted, Effective October 1, 2002, Repealed and Reenacted, Effective April 1, 2007. 3. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service, United States Department of Agriculture. 4. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Wright-McLaughlin Engineers, Denver, Colorado, Revised April 2008. APPENDIX A.1 Hydrologic Computations CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: 838-014 Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: ATC Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date: Concrete …….......……………….….……….………………..….…………………………………0.95 90% Gravel ……….…………………….….…………………………..……………………………….. 0.50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..…………………………………………….. 0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year C f = 1.25 Basin ID Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Pavers (ac) Area of Lawn, Rain Garden, or Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. 1 7082 0.16 0.000 0.012 0.035 0.000 0.116 0.38 0.38 0.48 26% 2 11756 0.27 0.000 0.100 0.086 0.000 0.084 0.70 0.70 0.88 62% 3 837 0.02 0.000 0.000 0.000 0.000 0.019 0.15 0.15 0.19 0% DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. 10-year Cf = 1.00 January 15, 2017 Overland Flow, Time of Concentration: Project: 838-014 Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) 2-yr Tc Rational Method Equation: Project: 838-014 Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: 1 1 0.16 15 15 14 0.38 0.38 0.48 1.90 3.24 6.71 0.12 0.20 0.52 2 2 0.27 9 9 9 0.70 0.70 0.88 2.30 3.93 8.21 0.44 0.74 1.94 3 3 0.02 5 5 5 0.15 0.15 0.19 2.85 4.87 9.95 0.01 0.01 0.04 DEVELOPED RUNOFF COMPUTATIONS C100 Design Point Flow, Q100 (cfs) Flow, Q2 (cfs) 10-yr Tc (min) 2-yr Tc (min) C2 Flow, Q10 (cfs) Intensity, i100 (in/hr) Basin(s) ATC January 15, 2017 Intensity, i10 (in/hr) Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 C10 Area, A (acres) Intensity, i2 (in/hr) 100-yr Tc (min) Q  C f  C  i  A  APPENDIX A.2 Hydraulic Computations Hydraflow Plan View Project File: Outfall.stm No. Lines: 1 01-17-2017 Hydraflow Storm Sewers 2005 Hydraulic Grade Line Computations Page 1 Line Size Q Downstream Len Upstream Check JL Minor coeff loss Invert HGL Depth Area Vel Vel EGL Sf Invert HGL Depth Area Vel Vel EGL Sf Ave Enrgy elev elev head elev elev elev head elev Sf loss (in) (cfs) (ft) (ft) (ft) (sqft) (ft/s) (ft) (ft) (%) (ft) (ft) (ft) (ft) (sqft) (ft/s) (ft) (ft) (%) (%) (ft) (K) (ft) 1 15 2.00 4974.24 4974.81 0.57 0.54 3.70 0.21 4975.02 0.541 30.5 4974.30 4975.02 0.72 0.74 2.71 0.11 4975.14 0.236 0.389 0.118 0.00 0.00 Project File: Outfall.stm Number of lines: 1 Run Date: 01-17-2017 Hydraflow Storm Sewers 2005 APPENDIX B USDA Soils Information United States Department of Agriculture 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 Natural Area, Colorado Resources Conservation Service September 26, 2016 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/portal/ nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (http:// offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means 2 for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................7 Soil Map................................................................................................................8 Legend..................................................................................................................9 Map Unit Legend................................................................................................10 Map Unit Descriptions........................................................................................10 Larimer County Area, Colorado......................................................................12 81—Paoli fine sandy loam, 0 to 1 percent slopes.......................................12 References............................................................................................................14 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil scientists classified and named the soils in the survey area, they compared the 5 individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil- landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 6 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 7 8 Custom Soil Resource Report Soil Map 4493150 4493160 4493170 4493180 4493190 4493200 4493210 4493220 4493230 4493240 4493250 4493150 4493160 4493170 4493180 4493190 4493200 4493210 4493220 4493230 4493240 4493250 493610 493620 493630 493640 493650 493660 493670 493680 493690 493700 493710 493720 493730 493740 493750 493760 493610 493620 493630 493640 493650 493660 493670 493680 493690 493700 493710 493720 493730 493740 493750 493760 40° 35' 24'' N 105° 4' 31'' W 40° 35' 24'' N 105° 4' 25'' W 40° 35' 20'' N 105° 4' 31'' W 40° 35' 20'' N 105° 4' 25'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 35 70 140 210 Feet 0 10 20 40 60 Meters Map Scale: 1:740 if printed on A landscape (11" x 8.5") sheet. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of Map Unit Legend Larimer County Area, Colorado (CO644) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 81 Paoli fine sandy loam, 0 to 1 percent slopes 0.7 100.0% Totals for Area of Interest 0.7 100.0% 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 intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. Custom Soil Resource Report 10 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. Custom Soil Resource Report 11 Larimer County Area, Colorado 81—Paoli fine sandy loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: jpxx 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 Paoli and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Paoli Setting Landform: Stream terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium Typical profile H1 - 0 to 30 inches: fine sandy loam H2 - 30 to 60 inches: fine sandy loam, sandy loam, loamy sand H2 - 30 to 60 inches: H2 - 30 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: Very low Capacity of the most limiting layer to transmit water (Ksat): High (2.00 to 6.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 15 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Very high (about 16.5 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: A Ecological site: Overflow (R067BY036CO) Hydric soil rating: No Minor Components Caruso Percent of map unit: 6 percent Custom Soil Resource Report 12 Hydric soil rating: No Table mountain Percent of map unit: 6 percent Hydric soil rating: No Fluvaquentic haplustolls Percent of map unit: 3 percent Landform: Terraces Hydric soil rating: Yes Custom Soil Resource Report 13 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http://www.nrcs.usda.gov/wps/ portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 14 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 15 APPENDIX C LID Design Information Basin ID Total Required WQ Volume (cf) Flow, WQ (cfs) Chamber Type Chamber Release Rate a (cfs) Chamber Volume b (cf) Installed Camber w/ Aggregate c (cf) Mimimum No. of Chambers d Total Release Rate e (cfs) Required Storage Volume by FAA Method (cf) Provided Chamber Volume f (cf) Total Installed System Volume g (cf) 1 221 0.31 SC-310 0.016 14.70 35.70 7 0.11 87 103 250 SC-740 a. Release rate per chamber, limited by flow through geotextile with accumulated sediment. b. Volume within chamber only, not accounting for void spaces in surrounding aggregate. c. Volume includes chamber and void spaces (40%) in surrounding aggregate, per chamber unit. d. Number of chambers required to provide full WQCV within total installed system, including aggregate. e. Release rate per chamber times number of chambers. f. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume. g. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV. Chamber Configuration Summary D:\Projects\838-014\Drainage\LID\838-014 Chamber Summary CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: Jefferson & Linden Restaurant Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: A. Reese Asphalt ……....……………...……….....…...……………….………………………………….0.95 . 100% Date: Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….0.50 . 40% Roofs …….…….………………..……………….…………………………………………….0.95 . 90% Pavers…………………………...………………..…………………………………………….0.40 . 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….0.15 . 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25 Basin ID Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Pavers (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. 1 0.28 0.00 0.08 0.13 0.00 0.00 0.06 0.79 0.79 0.99 70% DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. 10-year Cf = 1.00 November 18, 2016 Overland Flow, Time of Concentration: Project: Jefferson & Linden Restaurant Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) 2-yr Tc Rational Method Equation: Project: Jefferson & Linden Restaurant Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: Design Point Basin(s) Area, A (acres) 2-yr Tc (min) 10-yr Tc (min) 100-yr Tc (min) C2 C10 C100 Intensity, i2 (in/hr) Intensity, i10 (in/hr) Intensity, i100 (in/hr) Flow, Q2 (cfs) Flow, Q10 (cfs) Flow, Q100 (cfs) Flow, WQ (cfs) 1 1 0.28 5 - - 0.79 - - 2.85 - - 0.6 - - 0.31 DEVELOPED RUNOFF COMPUTATIONS A. Reese November 18, 2016 Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 Q = C f ( C )( i )( A ) Chamber Dimensions SC-310 Width (in) 34.0 Length (in) 85.4 Height (in) 16.0 Floor Area (sf) 20.2 Chamber Volume (cf) 14.7 Chamber/Aggregate Volume (cf) 29.3 Flow Rate* 0.35 gpm/sf 1 cf = 7.48052 gal 1 gallon = 0.133681 cf 1 GPM = 0.002228 cfs *Flow rate based on 1/2 of Nov 07 QMAX in Figure 17 of UNH Testing Report SC-310 Flow Rate/chamber (cfs) 0.015724 StormTech Chamber Data Chamber Flow Rate Conversion (gpm/sf to cfs) Chamber Flow Rate D:\Projects\838-014\Drainage\LID\838-014 Chamber Summary Jefferson & Linden Restaurant Fort Collins, Colorado A. Boese Date: November 18, 2016 Basin No.: 1 1 WQ 0.79 Area (A)= 0.28 acres Quantity Storage 87 ft 3 Max Release Rate = 0.11 cfs Time Time Ft.Collins WQ Intensity Q2 Inflow (Runoff) Volume Outflow (Release) Volume Storage Detention Volume (mins) (secs) (in/hr) (cfs) (ft 3 ) (ft 3 ) (ft 3 ) 5 300 1.43 0.3 95 33 62 10 600 1.11 0.2 147 66 81 15 900 0.94 0.2 186 99 87 20 1200 0.81 0.2 214 132 82 25 1500 0.72 0.2 237 165 72 30 1800 0.65 0.1 259 198 61 35 2100 0.59 0.1 272 231 41 40 2400 0.54 0.1 284 264 20 45 2700 0.50 0.1 296 297 -1 50 3000 0.46 0.1 305 330 -25 55 3300 0.44 0.1 318 363 -45 60 3600 0.41 0.1 326 396 -70 65 3900 0.39 0.1 332 429 -97 70 4200 0.37 0.1 339 462 -123 75 4500 0.35 0.1 343 495 -152 80 4800 0.33 0.1 350 528 -178 85 5100 0.32 0.1 355 561 -206 90 5400 0.31 0.1 364 594 -230 95 5700 0.29 0.1 366 627 -261 100 6000 0.28 0.1 372 660 -288 105 6300 0.27 0.1 376 693 -317 110 6600 0.26 0.1 380 726 -346 115 6900 0.26 0.1 389 759 -370 120 7200 0.25 0.1 390 792 -402 1. Release rate governed by flow through geotexile. See StormTech Data and Chamber Summary for additional information. Chamber Volume Calculation | FAA Method Project: Project Location: Calculations By: Input Variables Results Project Title Date: Project Number Calcs By: Client Basins 0.8 WQCV = Watershed inches of Runoff (inches) 70.00% a = Runoff Volume Reduction (constant) i = Total imperviousness Ratio (i = Iwq/100) 0.220 in A = 0.28 ac V = 0.0051 ac-ft V = Water Quality Design Volume (ac-ft) WQCV = Water Quality Capture Volume (inches) A = Watershed Area (acres) 221 cu. ft. Drain Time a = i = WQCV = Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event Jefferson & Linden Restaurant November 18, 2016 838-014 A. Reese Vaults 0.220 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 WQCV (watershed inches) Total Imperviousness Ratio (i = Iwq/100) Water Quality Capture Volume 6 hr 12 hr 24 hr 40 hr WQCV = a ( 0.91 i 3 - 1 . 19 i 2 + 0 . 78 i ) WQCV = a ( 0.91 i 3 - 1 . 19 i 2 + 0 . 78 i ) V * A 12 WQCV ÷ ø ö APPENDIX D Master Basin Modeling Summary 1 Modeling Summary Report Date: January 11, 2017 Project: Jefferson and Linden Restaurant Fort Collins, Colorado Attn: Mr. Shane Boyle Fort Collins Utilities 700 Wood Street Fort Collins, Colorado 80524 Dear Mr. Boyle: This modeling summary report is intended to supplement the PDP and FP Drainage reports for the Jefferson and Linden Restaurant project. The proposed development site is located just northwest of the intersection of Jefferson Street and Lindon Street in Fort Collins, Colorado. The site is located within the study area identified in the “Downtown River District (DTRD) Final Design Report”, by Ayres Associates, dated February 2012. The site lies within several master plan sub-basins, specifically Basins 110, 111, 206, and 210, as shown in on the attached “Exhibit B-Future Development Map for DTRD Area” (Please see Attachment 1). As we have discussed with you, we would like to take portions of Basins 110, 111, and 210, with a sum total of 0.40 acre, and incorporate these portions into Basin 206. In doing so, we will be routing the Jefferson and Linden Restaurant project site into the recently completed Downtown River District “Storm Line B”. Thus, we are introducing an additional 0.40 acres of undetained drainage area into this system. Hydrologic modeling was completed in this report utilizing the computer program EPA SWMM 5. Specifically, the proposed site is located within SWMM Basin 206, and the updated modeling completed for this study incorporates an additional 0.40 acres as discussed above. We note that Basin 206 had an assumed percent impervious value of 90% in the original Ayres model, and we have not changed this parameter. The proposed site plan will not exceed this percent impervious assumption. Please see the disk provided in Attachment 3 for an electronic copy of the modified master plan SWMM Model. Table 1, below, summarizes changes in Peak 100-year discharge at SWMM Links B6 (site tie-in point) through B3 (several links downstream of the site). Table 2, below. summarizes changes in 100-year HGL at SWMM Manholes MHB6 through B3. Please see Attachment 2 for selected portions of the Downtown River District “Storm Line B” plan set, and we note that the minor 2 increases in HGL summarized in Table 1, below will not bring HGL above junction rim elevation at any junction. TABLE 1 – Summary of Changes in Peak 100-year Flow Link Original Ayres Model Peak 100-yr Flow Revised Model Peak 100-yr Flow Change in Peak 100-yr Flow (CFS) B3 302.49 304.01 1.52 B4 285.26 287.26 2 B5 151.59 153.22 1.63 B6 109.55 111.64 2.09 TABLE 2 – Summary of Changes in 100-year HGL Node Original Ayres Model Peak 100-yr Manhole Depth (FT) Original Ayres Model 100-yr HGL (FT) Revised Model Peak 100-yr Manhole Depth (FT) Revised Model 100- yr HGL (FT) Manhole Rim Elev. (FT) Change 100-yr HGL (FT) MHB2 4.07 4961.39 4.13 4961.45 4965.03 0.06 MHB3 5.4 4964.02 5.49 4964.11 4968.21 0.09 MHB4 6.02 4964.9 6.09 4964.97 4969.1 0.07 MHB5 6.26 4966.78 6.39 4966.91 4970.39 0.13 MHB6 6.11 4969.45 6.3 4969.64 4974.19 0.19 In summary, the modeling provided adequately addresses any potential concerns related to storm line capacity in the recently completed Downtown River District “Storm Line B”. This study shows there is negligible impact due to the proposed minor adjustments to master plan Basins 110, 111, 206, and 210. Please feel free to contact me with any questions you may have. Sincerely NORTHERN ENGINEERING Aaron Cvar, PhD, PE Senior Project Engineer Attachment 1 Annotated Exhibit B-Future Development Map for DTRD Area Attachment 2 Selected Portions of Downtown River District “Storm Line B” Plan Set Attachment 3 Modified Master Plan SWMM Model (on Disk) APPENDIX E Erosion Control Report Final Erosion Control Report EROSION CONTROL REPORT A comprehensive Erosion and Sediment Control Plan (along with associated details) has been included with the final construction drawings. It should be noted, however, that any such Erosion and Sediment Control Plan serves only as a general guide to the Contractor. Staging and/or phasing of the BMPs depicted, and additional or different BMPs from those included may be necessary during construction, or as required by the authorities having jurisdiction. It shall be the responsibility of the Contractor to ensure erosion control measures are properly maintained and followed. The Erosion and Sediment Control Plan is intended to be a living document, constantly adapting to site conditions and needs. The Contractor shall update the location of BMPs as they are installed, removed or modified in conjunction with construction activities. It is imperative to appropriately reflect the current site conditions at all times. The Erosion and Sediment Control Plan shall address both temporary measures to be implemented during construction, as well as permanent erosion control protection. Best Management Practices from the Volume 3, Chapter 7 – Construction BMPs will be utilized. Measures may include, but are not limited to, silt fencing along the disturbed perimeter, gutter protection in the adjacent roadways and inlet protection at existing and proposed storm inlets. Vehicle tracking control pads, spill containment and clean-up procedures, designated concrete washout areas, dumpsters, and job site restrooms shall also be provided by the Contractor. Grading and Erosion Control Notes can be found on the Utility Plans. The Final Plans contain a full-size Erosion Control sheet as well as a separate sheet dedicated to Erosion Control Details. In addition to this report and the referenced plan sheets, the Contractor shall be aware of, and adhere to, the applicable requirements outlined in the Development Agreement for the development. Also, the Site Contractor for this project will be required to secure a Stormwater Construction General Permit from the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division – Stormwater Program, prior to any earth disturbance activities. Prior to securing said permit, the Site Contractor shall develop a comprehensive StormWater Management Plan (SWMP) pursuant to CDPHE requirements and guidelines. The SWMP will further describe and document the ongoing activities, inspections, and maintenance of construction BMPs. MAP POCKET VAULT ELEC VAULT ELEC T CONTROL IRR CONTROL IRR CONTROL IRR VAULT ELEC VAULT ELEC VAULT ELEC ELEC ELEC VAULT ELEC VAULT ELEC TRAFFIC VAULT TRAFFIC VAULT TRAFFIC VAULT S VAULT ELEC MW C.O. X X X X X X X X X X 10" W 10" W 10" W 10" W 10" W 10" W 10" W 10" W 6" W 6" W 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 6" SS 15" SS 15" SS 15" SS 15" SS 15" SS 15" SS 15" SS 15" SS 15" SS 15" SS 15" SS C S TF X X X X X X X X X X X X X X X X X X X X X E E E E E E E E E E UD UD 1 2 1 JEFFERSON STREET (70' PUBLIC R.O.W.) LINDEN STREET (100' PUBLIC R.O.W.) 2 3 3 EXISTING INLET OUTFALL PIPE CHAMBER OUTLET STRUCTURE EXISTING INLET ROOF LEADERS ROOF LEADERS TRENCH DRAIN STORMTECH CHAMBER No. Revisions: By: Date: REVIEWED BY: N. Haws DESIGNED BY: DRAWN BY: SCALE: PROJECT: 838-014 Sheet JEFFERSON AND LINDEN RESTAURANT These drawings are instruments of service provided by Northern Engineering Services, Inc. and are not to be used for any type of construction unless signed and sealed by a Professional Engineer in the employ of Northern Engineering Services, Inc. NOT FOR CONSTRUCTION REVIEW SET ENGINEER ING N O R T H E RN 01/18/17 301 North Howes Street, Suite 100 Fort Collins, Colorado 80521 www.northernengineering.com Phone: 970.221.4158 DATE: JAN. 18, 2017 of 16 C600 DRAINAGE EXHIBIT A. Cvar A. Boese 1"=20' ( IN FEET ) 0 1 INCH = 20 FEET 20 20 40 60 NORTH LEGEND: 4953 PROPOSED CONTOUR 93 PROPOSED STORM DRAIN PROPOSED SWALE EXISTING CONTOUR PROPOSED CURB & GUTTER PROPERTY BOUNDARY PROPOSED INLET 1 DESIGN POINT FLOW ARROW DRAINAGE BASIN LABEL DRAINAGE BASIN BOUNDARY PROJECT BENCHMARKS NOTES: 1. REFER TO THE "FINAL DRAINAGE & EROSION CONTROL REPORT FOR JEFFERSON AND LINDEN RESTAURANT" BY NORTHERN ENGINEERING, DATED JANUARY 11, 2017 FOR ADDITIONAL INFORMATION. BASIN DESIGNATION BASIN AREA (AC) FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION PROPOSED UNDERDRAIN UD PROJECT DATUM: NAVD 88 BENCHMARK #1: City of Fort Collins Benchmark 5-00: On top of curb at the signal pole base at the Northwest corner of Linden St. and Jefferson St. Elevation: 4978.05 BENCHMARK #2: City of Fort Collins Benchmark 1-13: Southwest corner of College Ave. and Maple St., on a concrete traffic signal base. Elevation: 4979.75 1 CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE, OR EXCAVATE FOR THE MARKING OF UNDERGROUND MEMBER UTILITIES. CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow. Call before you dig. R 14 On-Site LID Treatment Project Summary Total Impervious Area 10,991 sf Target Treatment Percentage 75% Minimum Area to be Treated by LID measures 8,243.23 sf Infiltration Gallery/Underground Vaults Total Vault Treatment Area 9,342 sf Total Treatment Area 9,342 sf Percent Total Project Area Treated 85.0% DRAINAGE SUMMARY TABLE DESIGN POINT BASIN ID TOTAL AREA (acres) C10 C100 10-yr Tc (min) 100-yr Tc (min) Q10 (cfs) Q100 (cfs) 1 1 0.16 0.38 0.48 15.0 14.4 0.20 0.52 2 2 0.27 0.70 0.88 9.0 8.7 0.74 1.94 3 3 0.02 0.15 0.19 5.0 5.0 0.01 0.04 ç è = æ 12 hr D:\Projects\838-014\Drainage\LID\838-014_Water Quality Volume_Vaults Design Point Design Storm Required Storage Volume Developed "C" = D:\Projects\838-014\Drainage\LID\838-014 FAA_Chamber\ (min) 10-yr Tc (min) 100-yr Tc (min) 1 1 No 0.25 - - 11 2.06% 4.2 - - 124 1.22% 2.21 0.9 0 n/a N/A N/A 5 - - DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Gutter Flow Swale Flow Design Point Basin Overland Flow A. Reese Time of Concentration November 18, 2016 (Equation RO-4) ( ) 3 1 1 . 87 1 . 1 * S Ti C Cf L - = the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 10, Sep 22, 2015 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Apr 22, 2011—Apr 28, 2011 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 9 (min) 10-yr Tc (min) 100-yr Tc (min) 1 1 No 0.15 0.15 0.19 93 1.50% 15.0 15.0 14.4 0 0.00% N/A N/A 0 0.00% N/A N/A 15 15 14 2 2 No 0.15 0.15 0.19 35 2.00% 8.3 8.3 8.0 60 0.50% 1.41 0.7 0 0.00% N/A N/A 9 9 9 3 3 No 0.15 0.15 0.19 5 2.00% 3.2 3.2 3.0 0 0.50% N/A N/A 0 0.00% N/A N/A 5 5 5 DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Gutter Flow Swale Flow Design Point Basin Overland Flow ATC January 15, 2017 Time of Concentration (Equation RO-4)   3 1 1 . 87 1 . 1 * S C Cf L Ti  