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HomeMy WebLinkAboutCivil Drainage PlanJune 23,2025 William & Catherine Kenworthy 223W. Menomonee St. Chicago, lL 60614 MOUNTATN CROSS ENGINEERING, INE. Civil and Environmental Consulting and Design F.ili-t.:ii';r) "JtJhl [] 2 ?fi?5 {.ii'.i ' l' :r'' {:'..11i:i"i'Y Lr .. \ri i':;ii.li'f RE Kenworthy Residence, Lot 21 Ranch at Coulter Creek, Garfield Countyo CO - Drainage Report Dear Mr. & Mrs. Kenworthy The purpose of this correspondence is to evaluate the construction of the proposed residence on Lot 2l at the Ranch at Coulter Creek, from a storm water perspective and provide design recommendations pertaining to runoff management for incorporation into the site design. These recommendations were generated from the site plans that were submitted to our office. Refer to the plan sheets that show the design recommendations and details. Attached are the drainage.. calculations that were generated. The project is at an elevation of approximately 7465 feet above sea level. Ultimately, runoff from the site will travel into the regional detention ponds for the subdivision through a series of conveyances and storm drain appurtenances. Runoff from snowmelt is typically very large in volume but because it happens over a much longer time period, the peak flows are usually less than a rainfall event. Therefore, storm water is defined in this study to be surface water that is a direct result from a rainfall event. The site is not impacted by any floodplain boundary. No drainage studies are known to have been performed specific to this lot. Storm water from the site is evaluated in accordance with the standards of applicable sections of the Garfield County LUDC. All flows are listed in units of cubic feet per second (cfs) unless otherwise noted. Methodoloey The design of the drainage plan begins with a calculation of the flowrate of water that will be produced from a rainfall event. Since the watershed basin is small (less than 90 acres), the Rational method was used for estimating the amount of runoff that will occur. This method calculates runoff (Q) in cubic feet per second (cfs) from basin area (A) in acres, runoff coefficient (C), dnd rainfall intensity (I) in inches per hour: Q:C*IxA 826% Grand Avenue, Glenwood Springs, CO 81601 F: 970.945.5 544 F : I 70.945.5558 www. tnountaincross-eng. coin Kenworthy Jttne,2025 Page 2 of 4 When acres and inches per hour are used as the units, the conversion into cubic feet per second is 1.008 but is usually ignored and it has been here. The runoff coefficient is a dimensionless coefficient. Basin Area Drainage basins have the characteristic that any precipitation falling within that area will drain to the same point of discharge. The project basin was delineated from project topography, project site plan, and building architecture. Runoff Cofficient A runoff coefficient is assigned to each basin that gives a relationship between the amount of precipitation that becomes surface water and the amount of water that is lost to infiltration, evaporation, or transpiration. The runoff coefficient is a function of drainage basin soil types, surface area, andlor land-use. Because the land-use and the surface cover often vary through the project, a composite coefficient is often assigned to each drainage basin, based on the weight of the areas and their respective coefficients. Rainfall Intensity Rainfall intensity is determined from intensity duration frequency curves, or IDF curves. IDF curves are graphs of, more or less, parallel frequency curves that yield rainfall intensities based on storm durations. Frequency; The return frequency of a rainfall storm is the statistical probability thatagiven storm event will occur on average in a given period. For instance a 100- year storm has the statistical probability of occurring once in a 100 year span or it has a lo/o chance of occurring in any given year. It is important to emphasize that it is based on probability statistics and therefore does not reflect actual storm frequency. Storms of a 100-year magnitude can occur in sequential years, even in the same year. The return frequency of design is chosen and then referred to as the design storm. Duration: The duration of a storm is chosen to coincide with the time of concentration. The FAA Overland flow equation was used to estimate the time of concentration. The parameters needed to determine the flow elements include length, slope, and the Rational runoff coeff,rcient. The theory states that if the duration is equal to the time of concentration, the length of time will be adequate for the entire basin to contribute flow. Analvsis In general, the site is at the top of a ridge and has very little contributary area to develop significant storm flows. Project basins were delineated based on a review of aerial photography, roof lines, site grading, and project topography. Only the largest roof area was analyzed for downspout sizing. The driveway culvert contributory area was analyzed with the culvert and swale sized to convey this area; the largest contributory area. Mountain Cross Engineering. lnc. Civil ancl Environrnental Ccnsulting and Design 826 1/. Grand Avenue, Glenwood Springs, CO 81601 P: 970.945.5544 F : 970.945.5558 www.mountaincross-eng.com Kenworthy June,2025 Page 3 of4 All proposed storm water is captured and conveyed overland into either swales or piped to suitable gravity outlets. Runoff coefficients were determined based on land use and percentage imperviousness. The parameters for calculating the time of concentration were determined from the site, slope, length, and land uses. The times of concentration for the site basins are 5 minutes or 12 minutes. The calculations are attached. The rainfall intensities were determined by using the appropriate storm curve, duration to match the time of concentration, and the NOAA precipitation data. The basin flow rates were calculated based on the Rational Method and type C soils. The calculations are attached. Basin Description Area (acres) Coefficient Flow (cfs) Proposedl-25yr 0.03 0.95 0.16 Proposed2-25yr 0.4t 0.53 0.63 Water Oualitv Water quality will be provided by filtration from existing undisturbed vegetation. Temporary structures are intended to be used during construction activities. Permanent structures are intended to be used continually after the construction activities have been completed. Temporary erosion control measures that arc to be employed during construction have been designed to contain sediment on the site and to mitigate erosion from construction activities. Silt fencing will be placed around the downhill limits of disturbance. Rock socks will be placed at inlets and in the thalwegs of swales. Vehicle tracking pad is proposed. Permanent erosion control measures are revegetation ofdisturbed areas and design ofconveyances to prevent erosion. The site is expected to disturb less than one acre and therefore will not require a permit from CDPHE. Detention As a point of history, the original drainage for the subdivision is assumed to have anticipated that houses would be constructed on platted lots and the existing culverts and roadside ditches in the subdivision were constructed with culverts sized for full build-out. The existingdrainage network within the subdivision drains to an existing pond that was also assumed to be sized adequately for regional detention and water quality treatment. That being assumed correctly, no additional detention would be warranted specific toLot2l. Maintenance Maintenance will be required periodically for the drainage system. At a minimum the following should be done bi-annually in the spring and fall: the pipes and drainage appurtenances should be Mountain Cross Engineering. lnc. Givil and E*virsnmental Consulting and Design 826'/. Grand Avenue, Glenwood Springs, CO 81601 P: 970.945.5544 F : 970.945.5558 www.mountaincross-eng.com I(cnrvorthy Juttc,2025 Pagc 4 of4 clcanecl and clcarecl of deblis. llcat tape shoulcl bc chccltcd to vclily that it is wolking;rropelly an(l it shoulcl lrc turncd ofJ'in tlrc spling and turttccl on in tlte fall. 'l'cmpot'tu'ily, the gettcral ttotes requirc thc mainlcnance ancl li'ecprcrtt inspection ol'tlte silt ltnce atttd rttck socks. Results .fhc drainagc pipcs and erosion control ale desigrtecl to aclequatcly convey and prevent erosiott ll'om the 25-year storn'1, per Garficld County regulations. Attached nre tlte calculntions. "fhc ploltoscd drainage pattcln is inturdcd to rnaintaitr lhc existing as tnrtclt as possiblc. All ploposecl storm water is capturccl ancl conveyed by pipes ancl swales to existing subclivision convsyances. T'hel'c is a ccrtain arnount of unccrtainty in hydLologic calculations. I-lowever, wltctt cottstl'ttcted in accordance with this report arrcl the clrainagc plfln, it is our opirrion that the clesigrt will safuly aonvey the rurrof['['lows and vr-rlume ol'tlre 2.5-ycar dr:sign stolttt evsnt lor this sitc and will not callse llooding clatnagr.: lo tlris clr acljaccnI sitcs. 'l'he conclusions and o;linions that al'e explessed atrove are basecl on thc ittftrnnatiotr avttilable at the tinre rrf prept'rration ol this report. Any adclitiouttl irtfornratiou prescnle<i afterward nray rcquirc that tlrcsc opiuions ntrd tltc Lccorllltlcudations be rnodilied. 'l'hauk you for tlre opportunily to provide lhis r:eport, I?eel h'ee to call if'yott have any c;ttcstirltts, concefns, or c0l]trnents. Sincerely, Arlouttl n (i'o.s'.r tn8 ti s I lalc. lll'j Ine 1n o/t ! ',\ Ms.ULrlsin-'C_ro_e-s-Ergrnee-Llr-tg,--l-ns. Civll and Envlronmental Consulting and Deslgn 828'1, Grand Avenue, Glenwood Sprlngs, CO 8160'l P: 970.945.5544 F: 970.945.5558 www.mountaincross-erlg.corn [tl oElz/8 FIGURE 1 Drainage Areas Analyzed Lot 21, Coulter Creek Ranch MOUNTATN CROSS ENGINEERING, INE. Civil and Environmental Consulting and Design 826 112 Grand Avenue Glenwood Springs, CO 81601 ph 970.945.5544 fx 970.945.5558 www.mountaincross+ng.com *llr 1'- !O' m Ctui tld. mltr ttarror@rten I 5tl-o:t USDA United States - Danartment of Agriculture NRCS 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 Gustom Soil Resource Report for Aspen-Gypsum Area, Golorado, Parts of Eagle, Garfield, and Pitkin Gounties i i i i I I I I I I I I I I I I I I 1 I I r1 i i June22,2025 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/ porta l/n rcs/ma i n/soi ls/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://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=n rcsl 42p2_05395 1 ). 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 Federalagencies, 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. lnformation 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, maritalstatus, familialstatus, 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 2 alternative means 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 lndependence Avenue, S.W., Washington, D.C.20250-9410 or call(800) 795-3272 (voice) or (202)720-6382 (TDD). USDA is an equalopportunity provider and employer. 3 Gontents Preface...... How Soil Surveys Are Made... Soil Map.... SoilMap..... Legend....... Map Unit Legend....... Map Unit Descriptions Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties..... 1 8-Cochetopa-Antrobus association, 12 to 25 percent slopes...... References 2 5 BI 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 5 Custom Soil Resource Report scientists classified and named the soils in the survey area, they compared the 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. lf 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. lnterpretations 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 6 Custom Soil Resource Report identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. 7 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. 8 = b Custom Soil Resource Report SoilMap 3151210 3 e_@ 315m 31524)315260 3152S 31534 390 27 56'N E 39p 27'56'N ap E E EI o 5h E + ap FIp s o h g 314S60 314W 315@ 31ffi 315G0 31540 Map Sah: 1 : 1,670 iF printed on A landspe (11" x 8.5) *ted. o2o4o80 red0501@mil 1n = aj =e_@ R N A I 390 2748'N l4ap projedton: lveb Mqcabr Corner@ordinahs: WGS84 Edgetics: UTM Ane 13N WGS84 315170 31520 315230 315260 3't529 9 Z74gN Custom Soil Resource Report MAP LEGEND MAP INFORMATION The soil surveys that comprise your AOI were mapped at 1:24,0Q0. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: 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 the version date(s) listed below. Soil Survey Area: Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties SurveyArea Data: Version 15, Aug 29,2024 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 25, 2021-Sep 5,2021 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background Area of lnterest (AOl) Area of lnterest (AOl) Soils d** Soil Map Unit Lines tr Soil Map Unit Points Special Point Features 19 Blowout ffi Borrow Pit X Clay Spot i.: Closed DePression H Gravel Pit ;, Gravelly Spot S Landfill f. Lava Flow ,l. Marsh or swamo€ .. Mine orQuarry @ Miscellaneous Water ff Perennial Water + Saline Spot ;": Sandy Spot € Severely Eroded Spot *, Sinkhole il' Slide or SliP @ Sodic Spot E Spoil Area S Stony Spot !:$ Very Stony Spot fj Wet SPot i! Other r- Special Line Features Water Features Streams and Canals Transportation Rails tu, lnterstate Highways Major Roads Local Roads Background I Aerial Photography 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. 10 MAP LEGEND Custom Soil Resource Report MAP INFORMATION imagery displayed on these maps. As a resuh, some minor of unit boundaries be evidenl. 11 Custom Soil Resource Report Map Unit Legend 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 arca. 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. lf 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 allthe 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. lf intensive use of small areas is planned, however, Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 18 Cochetopa-Antrobus association, 12 lo 25 percent slopes 10.4 100.0% Totals for Area of lnterest 10.4 100.0% 12 Custom Soil Resource Report 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 so/ 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 so/ 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 assocrafion 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. 13 Custom Soil Resource Report Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties 1 8-Cochetopa-Antrobus associati on, 12 to 25 percent slopes Map Unit Sefting National map unit symbol: iq53 Elevation: 8,500 to 10,500 feet Mean annual precipitation: 1B to 20 inches Mean annual airtemperature: 36 to 38 degrees F Frost-free period: 45 to 60 days Farmland classification: Not prime farmland Map Unit Gomposition Cochetopa and similar soils: 45 percent Antrobus and similar so/s; 35 percent Minor components; 20 percent Estimates are based on obseruations, descriptions, and transects of the mapunit Description of Gochetopa Sefting Landform : Mountains, fans La n dfo rm po sitio n (th ree-d i m e n si o n a l) : Lower th i rd of mo u nta i nfla n k Down-slope shape: Linear Across-s/op e shape : Linear Parent material: Alluvium derived from basalt Typical profile Hl -0 fo3rnches: loam H2 - 3 to 38 inches; clay loam H3 - 38 to 60 inches; gravelly clay loam Properties and qualities S/ope; 12 to 20 percent Depth to restrictive feature: More than B0 inches Drai n age c/ass: Well drained Runoff class; High Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20 to 0.60 in/hr) Depth to water fable: More than B0 inches Frequency of flooding: None Frequency of ponding: None Available water supply, 0 to 60 inches: High (about 10.4 inches) lnterpretive groups Land capability cl assification (i rrig ated); None specified Land capability classification (nonirrigated): 6e Hydrologic Soil Group: C Ecologicalsife; R048AY250CO - Subalpine Loam Other vegetative classification: subalpine loam (null-84) Hydric so/ rafing; No 14 Custom Soil Resource Report Description of Antrobus Setting Landform : Mountains, fans La n dfo rm positio n (th ree-d i m e n si o n al) : Lower th ird of mou ntai nflan k Down-slope shape : Linear Across-s/ope shape : Linear Parent material: Alluvium derived from basalt and/or colluvium derived from basalt Typicalprofile Hl - 0 to 13 inches.' very stony loam H2 - 13 to 60 inches; extremely stony loam Properties and qualities S/ope; 15 to 25 percent Depth to restrictive feature: More than B0 inches Drainage c/ass: Well drained Runoff class; High Capacity of the most limiting layer to transmit water (Ksat); Moderately high to high (0.20 to 2.00 in/hr) Depth to water fable; More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 10 percent Maximum salinity: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: Low (about 3.4 inches) lnterpretive groups Land capability cl assification (i rrig ated); None specified Land capabil ity cl assification (non i rrig ated) : 7 s Hydrologic Soil Group: B Ecologicalstfe: R048AY237CO - Stony Loam Other vegetative classification; Stony Loam (null-82) Hydric soi/ rafing: No Minor Gomponents Other soils Percent of map unit: 20 percent Hydric so/ rafing; No 15 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. Soilsurvey manual. Soil Conservation Service. U. S. Department of Ag riculture Handbook 1 B. http ://www. n rcs. usda. g ov/wps/po rta l/ n rcs/d eta i l/n ati o n a l/so i I s/?cid = n rcs'1 4 2p2 -0 5 4262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soilsurveys. 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 soiltaxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www. n rcs. 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/ h ome/?ci d = nr csl 42p2 _0 5337 4 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/land use/rangepasture/?cid=stelprdb 1 043084 16 Custom Soil Resource Report United States Department of Agriculture, Natural Resources Conservation Service National soil survey handbook, title 430-Vl. http://www.nrcs.usda.gov/wps/portal/ n rcs/d eta i l/so i I s/scienti sts/?cid = n rcs 1 42p2 _0 54242 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:ll www. nrcs. usda. gov/l nternet/FSE_DOCUMENTS I nrcsl 42p2-052290.pdf 17 NOAA Atlas 14, Volume 8, Version 2 Location name: Carbondale, Golorado, USA* Latitude: 39.4644', Longitude: -107.1488' Elevation: 7457 tl** * source: ESRI Maps** source: USGS ,ffi POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Deborah Martin, Sandra Pavlovic, lshani Roy, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Michael Yekta, Geoffery Bonnin NOAA, Nalional Weather Seruice, Silver Spring, Maryland PF tabular I PF-grap-hieel I lt/aps-&-acne.lS PF tabular Back to Top PF graphical PDS-based rect on estimates with 90% confidence intervals in inches/hou 1 recurrence interval ration 1 2 10 25 50 100 200 500 {000 1.38 2.O4 3.91 (3.1 0-5.05) 4.98 5.76 6.49 (4.60-9.13) 7.20 (4.86-10.5)5-min (1.10-1.76)(1.63-2.62)(3.74-6.65)(4.24-7.85) t.0{1.49 2.86 (2.27-3.70) 3.65 4.22 4.75 (3.37-6.68) 5.27 (3.56-7.67)10-min (0.810-1 .29)(1.20-1.92)(2.74-4,87)(3.1 0-5.74) 0.820 1.22 2.32 (1 .84-3.01) 2.96 3.43 3.86 (2.74-5.44) 4.28 (2.90-6.24l.15-min (0.660-1.05)(0.976-1.56)(2.23-3.96)(2.52-4.67) 0.554 0.790 1.44 (1 .14-1.87) 1.8'l (1.36-2,41] 2.08 2.33 (1.65-3.27) 2.56 (1.73-3.72)30-min (0.444-0.710)(0.632-1 .01)(1.53-2.83) 0.366 (0.294-0.46e) 0.487 0.823 (0.653-1.06) 1.02 (0.765-1.35) I .15 (0.850-1.57) 1.28 1.41 60-min (0.910-1 .80)(0.951 -2.05) o.227 (0.184-0.288) 0.289 0.462 0.561 0.633 o.701 0.766 (0.524-1.10)2-hr .371 0.177 (0.144-0.222) 0.214 0.322 0.385 0.431 0.476 0.520 358-0.741 )3-hr 1 0.116 0.132 0.182 148-0.227) 0.214 6-hr 144)1 09-0.1 o.o72 0.082 0.11 3 0.134 12-ht 10'l 140)107-O. 0.044 0.051 0.07'l 0.085 24-hr 061 0.026 0.030 0.043 0.051 2-day 1 ) 0.020 0.032 0.038 3-day 0.0{ 6 0.026 0.030 4-day 1 .030) 0.0,l1 0.017 014-0.020) 0.020 0.030 0.033 7-day 1 6-0.-0.041 0.013 0.0r 5 0.023 0.025 (0.011-0.015)3-0.6-0.031 0.008 007-0.01 o) 0.010 0.011 009-0,01 3) 0.012 0.0{ 3 0.0't4 0.015 011-0.021 )010-0.01 7)0-0. 0.007 006-0.008) 0.008 0.009 0.009 0.010 008-0.01 3) 0.01'l 0.012 .008-0.010) 0.004 0.006 005-0.006) 0.006 0.007 0.008 0.008 0.009 0,009 .007-0.0145-day .010) 0.003 0.004 0.005 004-0.005) 0.005 0.006 005-0.007) 0.007 0.007 005-0.009) 0.008 0.008 60-day 011) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). 8.06 (5.22-12.2) 8.66 (5.48-1 3.5) 5.90 (3.82-8.91) 6.34 (4.01-9.85) 4.80 (3.10-7.24) 5.{6 (3.26-8.01) 2.84 (1.84-4.29) 3.04 (1.92-4.71) 0.239 (0.1 83-0.31 7) I o.zss ll 0.292 l1o. r ss-o.eory I l1o. 204-0.41 sl 0.151 (0.11 7-0.1e8) 0.187 133-0.262) 0.169 ll 10. r zs-o.zzayllqo. 0.097 (0.076-0.125) fu-ros lT or2i llo.osz-o. ts1 l l1o.087-0. 1 67) 0.058 (0.046-0.074) I o.oes ll l(o.o5o-o.oB6)ll(0. 0.073 053-0.099) 0.043 (0.034-0.054) I- 0"048 _lt o"os4 Ito.osz o.ooelllto.03e-0.072) 0.034 (0.027-0.043) 0.038 0.043 031 -0.057) 0.022 (0.018-0.027) o.o24 r19-0.03 0.027 020-0.036) 0.017 (0.014-0.021) fo.oir-lt ooro l(0.014-0.024)ll(0.01 5-0.027) 1.56 (1 .01-2.35) r.66 (1.05-2.58) 0.845 (0.553-1.26) 0.900 (0.576-1.38) 0.574 (0.379-0.849) 0.614 ,0.394-0.931) 0.328 (n atn-n iP4\ 0.357 :0.231-0.533) 0.213 (0.144-0.308) 0.233 :0.153-0.343) 0.138 [0.095-0.1 98) 0.152 "0.101-0.221)0.084 (0.058-0.11 8) 0.092 :0.062-0.132) 0.061 /n ndr-n nRql 0.067 0.048 0.053 Please refer to NOAAAtlas 14 document for more information. '-'t- l- 101 PD5-based intensity-duration-frequency (lDF) curves Latitude: 19.4644", Longitude: -107.L488' 5 10 25 50 100 Average recurrence interval (yean) Averege recunence inte&€l (years) I 2 5 10 25 50 100 zAO 500 I 000 t c oco! L fg q. TJ d) d- 10 10-r -al0 trEC6qL!!L!>>>E E E F F f;f; 6 fi f +qs q€ s+s{; *S 8 d nurati# A An\* *J Rf;+8 101 10 10-r _Jt0 I -E \'6 fll o fu U rl) o. l2 200 500 1000 freated (GfrTl: SatJun zl ll 30 l0 2015 Back to Top_ Maps & aerials Small scale terrain li0AA Atlds 14, Volume 8, Version J i'I !1 l I .l 1 ! - !-i, , | .,'' j"qe.E- i:r "(.':'Jti + /: I i t- iI-,--I I 1_. -I .- Duration 5-nrln lo{nm ltum 30-mln 6ofitn 24t 3-hr 6+r tz-hr 24+r - ?-d8y - 3-day - 4-day - ?-dsy - ro-day - zo-day - 30-day - 46-day - 60-day ITY 3km Large_scale terrain -:i r-? Largg scale 100km r-) Large scale aerial .1 v q i r zl -t - 1.,: '-l I I !9'.,.! 't' l t '"1 -r 'a :l . -l I I r 100km - 60mi'. t '- r{. r} r-l r Back to Top I + + U S De p g rtrned_9lgg!0-rnelge National Oceanic and Atmosoheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spting, MD 20910 Questions?: H DSC.Questions@naaa. gov Disclaimer DRAINAGE CALCULATIONS for Lot21, Kenworthy, Coulter Creek '06t22t2025 Civil and Environmental ph g0,gig fi 970.95.5S0 ww,mouniainc.os*ng.@m MOUNTAIN CROSS ENGINEERINC, INC. Drainage Proposed 1 Surface description: Largest roof area PROPERTY GENER,AL SURFACE DATA Total Drainage Area: 1,500 sq. ft.0.03 ac RUNOFF COEFFICIENT Proposed Land Use Roof Hardscape & Paving Landscaped areas Pine and Aspen Sage and Grasses TOTAL BASIN ACERAGE sq. ft. or est. % 1,500 0 0 0 0 acres 0.03 0.00 0.00 0.00 0.00 0.03 imperviousness = 100% C25 = 0.95 TIME OF CONCENTRATION Overland Flow Time Upstream Elevation Dnstream Elevation Length 50 Slope 0.17 c2 Tc 4.290.25 Channel Flow Time Upstream Elevation Dnstream Elevation Length 0.0 Slope 0.00 K 7.000 Tc 0.00 Total 4.29 min RUNOFF lntensity (in/hr) Flowrate (cfs) 25-yr Storm 5.00 0.16 NOTES: - lf land use percentages are used, they have been estimated from satellite image - Conveyance coefficient K is based on "lawn" or vegetation lined channel DRAINAGE CALCULATIONS fOT Lol21, Kenworthy, Coulter Creek '0612212025 ph97qg'5glr -:. @ MOUNTAIN CROSS ENGINEERINC, INC. Civil and Environmenbl Consulting and Design 826 l/2 Gmnd Avenue Olsnw@d spdnqs, cO 81601 nage Proposed 2 Surface description: Proposed roof, hardscape improvements, and landscaping PROPERTY GENERAL SURFAGE DATA Total Drainage Area: 18,000 sq. ft. 0.41 ac. RUNOFF COEFFICIENT Proposed Land Use Roof Hardscape & Paving Landscaped areas Pine and Aspen Sage and Grasses TOTAL BASIN ACERAGE sq. ft. or est. % 1,025 2,730 acres 0.02 0.06 0.33 0.00 0.00 0.41 imperviousness = 21% HSG = C from Fig 6-2 14,245 0 0 C25 = 0.53 TIME OF CONCENTRATION Overland Flow Time Upstream Elevation Dnstream Elevation 7471.00 7465.00 Length 125 Slope 0.05 c2 0.25 Tc 10.22 Channel Flow Time Upstream Elevation Dnstream Elevation 7465.00 7462.90 Length 105.0 Slope o.o2 K 7.000 Tc 1.77 Total 11.99 min RUNOFF Intensity (in/hr) Flowrate (cfs) 25-yr Storm 2.86 0.63 NOTES: - lf land use percentages are used, they have been estimated from satellite image - Conveyance coefficient K is based on "lawn" or vegetation lined channel TJ -qJ(J 0)Ot] L \l-oc =d 1.00 o"B0 0.80 0.70 0.60 0.00 0"50 0.40 0.30 0.20 010 +- 2-!. r -X-5-yr f,- 1O-yr -x-25-yr *50-yr + 100-yr 0 10 20 30 40 50 so 70 80 Watershed Perc.entage lrnpervionsness. s/o go 100 Figure 6-3. Runoff rorlfrdrnt vs. watrrshed irnperviousnrss NRC S HSG C and D J\ -ffi f,{g Proposed Goefficients Channel Report Hydraflow Express Extension for Autodesk@ Civil 3D@ by Autodesk, lnc. 4 in. Downspout Gircular Diameter (ft)= 0.33 Invert Elev (ft) Slope (%) N-Value 0.19 0.1 60 0.05 3.13 0.57 0.23 0.33 0.34 3 00 00 01 =1 -z =Q Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (fUs) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Sunday, Jun222025 Section Calculations Compute by: Known Q (cfs) Known Q = 0.16 Elev (ft) 2.OO 1.75 1.50 1.25 1.00 0 1 v 0.75 Reach (ft) Ghannel Report Hydraflow Express Extension for Autodesk@ Civil 3D@ by Autodesk, lnc. Swale Triangular Side Slopes (z:1) Total Depth (ft) lnvert Elev (ft) Slope (%) N-Value Sunday, Jun222O25 =l =Q =1 =1 =Q 0.46 0.700 0.42 1.65 2.06 0.38 1.84 0.50 2.0000, 50 00 00 030 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (fVs) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft)Galculations Compute by: Known Q (cfs) Elev (ft) Known Q = 0.70 2.00 1.75 1.50 1.25 1.00 Section 1.5 Depth (ft) 1.00 0.75 0.50 0.25 0.00 0 1 32 0.75 .5 Reach (ft) 2.5 -0.25 Gulvert Report Hydraflow Express Extension for Autodesk@ Civil 3D@ by Autodesk, lnc. Gulvert lnvert Elev Dn (ft) Pipe Length (ft) Slope (%) lnvert Elev Up (ft) Rise (in) Shape Span (in) No. Barrels n-Value Culvert Type Culvert Entrance Coeff. K,M,c,Y,k Embankment Top Elevation (ft) Top Width (ft) Crest Width (ft) 2.60 30.00 1.00 2.90 15.0 Circular 15.0 1 0.012 Circular Concrete Square edge w/headwall (C) 0.0098, 2, 0.0398, 0.67, 0.5 00 00 00 Culvefi Galculations Qmin (cfs) Qmax (cfs) Tailwater Elev (ft) Highlighted Qtotal (cfs) Qpipe (cfs) Qovertop (cfs) Veloc Dn (ftls) Veloc Up (ft/s) HGL Dn (ft) HGL Up (ft) Hw Elev (ft) Hw/D (ft) Flow Regime Sunday, Jun222025 = 0.10 = 1.00 = Normal = 0.70 = 0.70 = 0.00 = 3.61 = 2.74 = 2.87 = 3.23 = 3.34 = 0.35 = lnlet Control H,! Depth (fl1 -L -L -A Elef rflr -? ?t 2.Ca 3]C 2 13 I tc -3 33 1 9-1 a5 r:rrcu ar l]ult erl 10 l5 2i 25 '_-_-_ _- Enrbifrl 3C 35 4X 51 Rei.h rfll 59 1/8"W x 87 3/4"H x 32 U2"D on a combustiblelloor H = 93" r,085 lbs 66 1/2"W x 81 3/4"H x 36 1/4"D uillotine 0peration 42314"W x42"H 37 114"W x36112"H 35 1/2" W{ronl 21 3/4"W back '13" deep 12" Rts '12' (more with elbows) N/A 4 medium logs 22" Yes (100,000 BTU max) N/A N/A Stove 0peration Straight Trim (included with f ireplace) N/A N/A N/A NIA FO.INT 0" 0" 0" 67"W x 24"D 2.2 R-value ULC U.S, Patent No, 8,479,723 Canadian Patent Pending This model qualifiesatthe EPA Phase 2 emissions level for U.S, EPA's Voluntary Fireplace Program. Defined as a fireplace by the 2015 pa(ticulate emissions standards. Door0pen 3,4 g/kg Door Closed 0.68 g/kg Linear 50Rumford 1O0OB Rumford 15008 Uptown 600 Clearance to Combustible Materials Certification 2O Note 1: These f ireplacep may be drilled out to accept an after-market gas log assembly, You may not install a gas lighter in any Renaissance f ireplace because the high firebox temperatures will burn out the log lighter very quickly, 0utside Dimensions Shipping Weight Shipping Crate Size Door Screen Door 0pening size Glass Viewing Size Firebox Dimensions Chimney Minimum Chimney Height lVasonry Chimney option Touch up Paint Color l\4aximum Fuel Load Maximum Log Length Gas Log Provision' HBS (Heat Recovery System) HRS Grills Trim HRS extensions HRS Grills 0utside Air Kit Refractory Brick Durable high temperature refractory reinforced with stainless steel pins, Vermiculite Panels High performance panels, 0racks and wear are more likely, Back Sides Floor Hearth Requirements Safety Patents Emissions 51"W x 80 l/4"H x 28 1/4"D ] rzo tn. 56"W x 78 3/4"H x 31 U4"D counterweiqhted counterweighted 34"Wx 37"H 29112"W x31112"H 27 1/2"W front 13 1/2"W back l2 3/4" deep r0" Bts l2'(more with elbows) N/A 3-4 medium logs 20" Yes (70,000 BTU max) N/A Straight Trim (included with fireplace) N/A N/A N/A N/A FO-INT 0" 0" 0" 45"W x 24"0 0.54 B-value u,s, Patent No, 8,479,723 Canadian Patent Pending This model qualifies atthe EPA Phase 2 emissions level for U,S. EPA's V0luntary Fireplace Program. Defined as a fireplace by the 2015 particulate emissions slandards. Door Open 3.0 g/kg Door Closed 1.0 g/kg 44 3/4"W x 56 5/8"H x 28 l/4"0 705 lbs 51"W x 63 1/2"H x 32"D Guillotine Glide'Bail system Guillotine Glide-Rail system 36 7/8"W x 26 l/8" H 28112"Wx20318" H 28 1/2"W x l3"D s" EXCEL (only) 12' FO-FDM8 Metallic Black 3-4 medium logs 24', Yes (50,000 BTU max) lncluded with f ireplace: Two 8" dia. outlet ducts - 5' length See paqe 13 for details Straight - E0-RUPST Frame = E0-8UPff F0-DUCTs = 5' outlet extension N/A N/A N/A FO-INT Included with lireplace Not available 0" 0" 0" 45"W x18"D Ember protection only I U1127 This model quali{ies at the EPA Phase 2 emissions level lor u.S. EPA'S Voluntary Fireplace Program, Defined as a{ireplace by the 2015 NSPS particulate emissions slandards, 0oor 0pen 4.8 g/kg Door Closed N/A 70 3/8"W x 66 3/8"H x 28 3/4"0 r '1,'130 lbs I 0 1 I 4"W x 69 1 I 2" H x 32 1 I 2" D : Counterweighted Guilloline 0peration Counterweighted Guillotine 0peration 50 7/16"W x 19 /8"H 45 7/8"W x l5 3/8"H 44112"W x14"0 't0" Rts 12' (more with elbows) N/A 4-5 medium logs 24', Yes (70,000 BTU max) Included with fireplace: Two 10" dia. outlet ducts - 5' length See page i3 for details, Straight Trim (included with lireplace) E0-DUCT = 5'outlet extension E0-LLGIN (Long linear intake grills): 52 1/2"x 6" E0-LLG-0UI (Long linear outlet grills): 52 l/2"x 6" E0-SG(Wall grillsfor8'ceilings)i13"x13" FO-INI lncluded with fireplace Not available 0" 0" 0" 74112"W x20"D Ember protection only Defined as a Iireplace by lhe 2015 NSPS particulate emissions slandards. N/A