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Drainage Reports - 12/10/2010
City of Ft. Collins Ap rov d Plans Approved By Date =1 �.a -w . u FINAL DRAINAGE STUDY AND EROSION CONTROL REPORT FOR TALON ESTATES June 25, 2007 Revised: December 21, 2007 Prepared for: Nadine Holter PO Box 272546 Fort Collins, CO 80527 Prepared by: Mary Mateo, EI Stewart & Associates, Inc. PO Box 429 103 S. Meldrum St. Fort Collins, CO 80521 Phone: (970) 482-9331 Fax: (970)482-9382 TABLE OF CONTENTS CERTIFICATION I. GENERAL LOCATION AND DESCRIPTION A. SITE LOCATION B. DESCRIPTION OF PROPERTY H. DRAINAGE BASINS AND SUB -BASINS A. MAJOR BASIN DESCRIPTION B. SUB -BASIN DESCRIPTION III. DRAINAGE DESIGN CRITERIA A. REGULATIONS B. HYDROLOGICAL CRITERIA C. HYDRAULIC CRITERIA IV. DRAINAGE FACILITY DESIGN A. GENERAL CONCEPT B. SPECIFIC DETAILS V. EROSION CONTROL VI. CONCLUSIONS VII. REFERENCES VIII. APPENDICES PAGE 2 3 3-4 I 6 7 7 7-8 8 9-11 11 12 13 1 CERTIFICATION I hereby certify that this report for the fmal drainage design of Talon Estates was prepared by me (or under my direct supervision) in accordance with the provisions of the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, for the owners thereof. icegisterea Frotessional Engi State of Colorado No. 35265 K I ' I. GENERAL LOCATION AND DESCRIPTION ■ A. Location Talon Estates (Project Site) is located in the northeast quarter of Section 28, Township 7 North, Range 69 West of the 61h Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. 1 The Site is bounded on the North and East by the Pleasant Valley and Lake Canal (PVLC); on the South by Falcon Drive and Tefft Acres, a subdivision of 1.3 acres or larger lots; and on the West by Falcon Drive and the Glantz MRD 5-53-92, being 3 lots of two acres or more. A Vicinity Map is provided in the Appendix. B. Description of Property ' The total Site area is approximately 9.36 acres, which includes the East 30 feet of Falcon Drive that runs North/South and 60 feet of ' Falcon Drive that runs East/West. It is currently vacant, sparsely vegetated with native grasses, and is being used as flood -irrigated pasture. The Site currently drains to the north and east, with slopes ranging from 0 to 5 percent, and outfalls to the PVLC. The Project Site is currently zoned Urban Estate (UE). This project proposes to develop 13 single-family dwellings; a new 53-foot wide local paved road; and a tract to be used for a wildlife buffer zone, ' detention, and utilities. Anticipated construction will consist of clearing, over lot grading, and construction of infrastructure, including underground utilities, asphalt street, concrete curb and gutter, concrete sidewalks, landscaped areas and the aforementioned dwelling units. ' As previously stated, the PVLC runs along the northern and eastern boundaries of the Site. There is also a shallow irrigation lateral running through the Site. This lateral begins in the southwest corner of the site and runs north, then in a northeasterly direction, and then turns southward and ends in the mid -section of the site, converting to ' sheet flow directed toward the PVLC. This lateral will be removed with development of the Site; however, the property will continue to maintain its irrigation rights. 3 Soil classifications for the Site are made up of Altvan-Santanta loam (0-3% slopes) and Fort Collins loam (3-5% slopes). See the Soil Conservation map and descriptions provided in the Appendix. These soils belong to the hydrologic soil group B, as assigned by the Natural Resources Conservation Service. They are deep and well drained, ' with moderate permeability. Depth to the seasonal high water table is indicated to be at greater than six feet. Runoff is slow to moderate, and the hazards of wind and water erosion are slight to moderate. ' II. DRAINAGE BASINS AND SUB -BASINS ' A. Major Basin Description ' This site lies within the Spring Creek drainage basin of the City of Ft. Collins. It is not within any floodplain boundary, as evidenced by the FEMA Flood Insurance Rate Map — Community Panel Number 080101 0192 C (See FIRMette in Appendix). No previous drainage studies have been done for this Site. ' As previously stated, the PVLC runs along the northern and eastern boundaries of the Site. There are no wetlands associated with the ' Site; however, the development will leave a tract to be used for a wildlife buffer zone, detention, and utilities along the canal. B. Sub -Basin Description ' The historic drainage patterns for this site are those that currently exist, as the Site is undeveloped. Existing drainage conditions and surface runoff are shown on the provided Existing Drainage ' Conditions Map. The entire Site ultimately drains to the PVLC; however, the Site was divided into six smaller basins to obtain a more accurate historic release rate. Historical Basins A and B drain northward, Basin C drains to the northeast, and Basins D through G drain to the east, with all runoff directed to the PVLC. Basin G is an ' offsite basin south of the Site that drains onto Falcon Drive. These flows will be passed through the Site at their historical rates, but will not be detained. 4 ' At the southeast corner of the Site, there is currently an 8" steel pipe ' that directs flows under Falcon Drive, and two 12" steel pipes that direct flow from the Site to the PVLC. These pipes will be removed with development of the Site. There is currently no detention provided for the Site. At the southeast corner of the Site, one detention pond will detain ' onite developed runoff. Runoff will be conveyed overland and via storm sewer to the detention pond and ultimately released via ' connection to an 15" storm pipe in Falcon Drive east of the Site. Developed Sub -basins The proposed site was divided into twelve sub -basins. Sub -basin ' runoff will be captured in the on -site drainage system and detained prior to release into the existing storm drain system in Falcon Drive east of the Site. Sub -basin Al consists of the north half of Falcon Drive that drains to Design Point (DP) 1 from the west. Sub -basin A2 consists of lots 11 thru 13 and the back portions of lots 8 thru 10, as well as the adjacent street areas in the southwest portion of the Site. This sub -basin also ' drains to the crosspan at DP1, where flows cross Broadwing Road to DP2. Sub -basin B includes the front portions of lots one through five and their adjacent street areas. It drains to DP2, joining flows from Sub -basins Al and A2. Those flows continue eastward to DP4, where they join flows from sub -basins E and F. Sub -basin E consists of the ' north half of Falcon Drive between DP2 and DP4, draining to DP4 from the west. Sub -basin F consists of the north half of Falcon Drive that drains to DP4 from the east. Flows at DP4 are intercepted by a triple Type R inlet in sump. Sub -basin D consists of the south half of Falcon Drive that directs runoff to DP3 from the east and the portion ' of offsite property that drains to that portion of road. Sub -basin C consists of the south half of Falcon Drive that drains to DP3 and the ' portion of offsite property that drains to that portion of road. Flows at DP3 are directed to the triple Type R inlet at DP4 via crosspan. Flows from DP3 and DP4 are then directed to the detention pond via storm pipe. W V Sub -basin G1 consists of the front portions of lots 8 thru 10, their adjacent street areas, and the southern half of Longwing Drive. Sub - basin G2 consists of the front portions of lots 6 and 7 and their adjacent street areas. Both G1 and G2 drain to DP5 from the south. Sub -basin G3 consists of the western half of Falcon Drive that drains to the low point and crosspan at DP5. Flows at DP5 are then captured via a sidewalk cut (12' long) and directed to the swale along the ' backsides of lots three through seven. Sub -basin H consists of the backsides of lots three through seven that sheet flow to the same swale, which will carry flows from sub -basins G and H to the detention pond. This swale includes a low -flow concrete trickle ' channel (v-pan). Sub -basin I consists of the back halves of lots one and two which 1 sheet flow directly to the detention pond. The release rate for the pond will consist of the 2-year historic flow ' for onsite areas, as well as the offsite area south and west of the site that drain to Falcon Drive (historic basin G). Release from the pond will be piped to existing storm pipe in Falcon Drive east of the Site. DRAINAGE DESIGN CRITERIA A. Regulations ' The analysis and design of the storm drainage system for this project ' was prepared in accordance with the criteria set forth in the City of Fort Collins Storm Drainage Design Criteria and Construction Standards and the Urban Drainage and Flood Control District's ' Urban Storm Drainage Criteria Manual (USDCAI). :on B. Hydrological Criteria ' 1. Design Rainfall City of Fort Collins Rainfall Intensity -Duration -Frequency Table for the Rational Method (Figures 3-la and 3-lb) ' 2. Runoff Method Rational 3. Design Storms a. Minor 2-year b. Major 100-year 4. Detention/ ' Storage Method Modified FAA C. Hydraulic Criteria Street and inlet capacities were calculated utilizing spre adsheets dsh p eets ' provided by Urban Drainage and nomography provided in the City of Fort Collins criteria. They are included in the appendix. ' The necessary pond volume was calculated utilizing Urban Drainage spreadsheets and the Modified FAA method and includes a Water ' Quality Catchment Volume of 0.18 acre-feet. The total required volume is 1.1 acre-feet. A detail for the outlet structure is included in the construction plans. The emergency overflow spillway was ' designed to accommodate the 100-yr inflow of 25.78 cfs at a depth (above weir) of six inches. IV. DRAINAGE FACILITY DESIGN ' A. General Concept ' The intent of the proposed drainage system is to safely convey the 2- year (minor) and 100-year (major) design storm runoff. Runoff will be conveyed by surface drainage structures (i.e. streets, swales, cross pans, curb and gutter) and by an underground storm sewer system. 7 ' Existing drainage patterns will be maintained and utilized as ' practicality permits. The general pattern of flow is toward the north and east, into the PVLC and to the southeast corner of the Site. The pond and outlet pipe will be located at this corner and will outfall to existing storm pipe in Falcon Drive east of the Site. Inlets will be used to capture drainage as street capacities are reached and swales and underground storm sewer used to convey the flow to the proposed detention pond. The pond will release flows at the two-year historic rate for the Site, in addition to flows from historic basin G south of the ' Site and proposed sub -basin G3 west of the Site. ' B. Specific Details All streets within the development will be two-lane, 30' flowline-to- 1 flowline residential streets, with Larimer County drive -over curb and gutter, two-sided parking and detached walks. Public drainage conveyance infrastructure such as curb and gutter, inlets and storm sewer are anticipated to remain in the public right-of- way. Drainage easements for public and private drainage infrastructure such as swales and landscape buffers will be provided in accordance with the appropriate regulations. The proposed detention ' facility will be privately owned and maintained. ' Onsite detention will be developed with the use of one grass -lined pond located at the `southeast corner of the project. The outlet is designed to release at the two-year historic rate (3.35 cfs) and will ' release to an 18" storm pipe in Falcon Drive that will connect with existing storm sewer east of the Site. Outfall is ultimately to Spring Creek. The detention pond will have side slopes of not greater than 4 to 1. ' Water Quality will be achieved by incorporation of a Water Quality Catchment Volume within the detention pond. The water quality ' plate will have one column of six rows of holes that are 3/4" in diameter and will be placed on the front of the outlet box and fronted by a screen. The outlet pipe is 18" in diameter and will be fronted by an orifice plate having a circular opening 9" in diameter in order to release at the historic 2-year rate of 3.35 cfs. 8 1 V. EROSION CONTROL Erosion control measures will be utilized to mitigate erosion and control sediment. The Site lies within the high rain erodibility, but low wind erodibility zones for the City of Fort Collins. Standard Best Management Practices will be utilized as indicated on the Erosion Control Plan. A copy is included with this report. Rainfall performance, effectiveness, and escrow calculations are included in the appendix, as is a copy of the anticipated construction sequence/schedule. Standard Best Management Practices will include the following: Vehicle Tracking Control: A vehicle tracking pad will be laid at the intersection of Broadwing Road and Falcon Drive in order to prevent the transport of sediment by construction vehicles entering and leaving the Site. This is a temporary measure and will be removed with the paving of Broadwing Road. Perimeter Silt Fencing: Silt fencing will be place along the north and east boundaries of the Site in order to prevent sediment transport due to stormwater runoff. Silt fencing will also be placed along the ' southern boundary in order to capture sediment erosion caused by wind. The Site is in the low wind erodibility zone; therefore, wind barriers such as this can be spaced at 1000' intervals. Prevailing winds are from the northwest. The Site is not more than 1000 feet from its northwest to southeast corners; therefore, fencing along the southern and eastern boundaries will be more than adequate to prevent sediment from leaving the Site due to wind erosion. This is a temporary measure and will be removed upon completion of construction and landscaping on the individual lots. ' Surface Rou hg ening: Surface roughening will be completed after fmal grading to create depressions two to four inches deep and four to ' six inches apart. These rows will run in a northeast to southwest direction in order to be perpendicular to the prevailing northwest winds. This will aid in prevention of sediment transportation due to rainfall or wind erosion. It is a temporary measure, as all disturbed areas are to be revegetated within one year if not otherwise stabilized. 9 Permanent Seeding and Landscaping: Permanent revegetation of Tract A (the swale and pond areas along the north and east sides of the Site) will be completed after final grading in order to prevent sediment transportation through that area and to the outlet. Vegetative cover consisting of the mix noted below shall be drill seeded at 10.75 pounds of pure live seed per acre. Mulch shall be used to stabilize the exposed surface. SEED MIX - Loam Soils — Perennial Grasses Species Recommended lb PLS/Acre Percent of Mix Mixed Ib PLS/Acre Western Wheatgrass 19.8 30 5.9 Blue Grama 3.0 25 0.75 Green Needlegrass 12.1 25 3.0 Switchgrass 5.6 20 1.1 TOTAL 10.75 A viable vegetative cover will also be established within one year on all disturbed areas not otherwise permanently stabilized. On -site landscaping areas shall be left in rough surface condition until covered with plantings and stone or wood mulch. Curb Socks: Curb socks will be placed at the north end of Falcon Drive, as the pavement will end at this location and the road turns to dirt/gravel past that point. This will prevent sediment being transported onto the Site. This is a temporary measure that will be maintained until permanent vegetation has taken place for the entire Site. Curb Cut Protection: Curb cuts at the north and east ends of Falcon Drive will be protected with wattles in order to prevent transport of sediment through the cuts. This is a temporary measure that will be ' maintained until permanent vegetation has taken place for the entire Site. ' Straw Bales: A straw bale dike will be constructed across the drainage swale approximately 500 feet downstream from the curb cut 1 at the north end of Falcon Drive. This will capture sediment being carried in the concrete V-pan and prevent its transport to the pond and 10 outlet. This is a temporary measure and will be maintained until ' permanent vegetation has taken place for the entire Site. Inlet Protection: All storm sewer inlets made operable during construction will have sediment entrapment facilities installed to prevent sediment -laden runoff from entering the inlet. This is a temporary measure and will be maintained until permanent vegetation ' has taken place for the entire Site. Water Quali Plate: As previously stated, the pond will include a water quality catchment volume that will drain through a water quality plate, designed to allow sediment deposit at the pond — preventing its ' release with stormwater at the outlet. This is a permanent measure, and the water quality plate is a part of the final outlet design. 1 VI. CONCLUSIONS ' The analysis and design of the storm drainage system for this project was prepared in accordance with the criteria set forth in the City of Fort Collins ' Storm Drainage Design Criteria and Construction Standards and the USDCM. No adverse affects to surrounding properties are anticipated from ' the development of this site. The design, if properly maintained and constructed, conveys, releases and protects the quality of storm water runoff up to and including the 100-year storm event in a safe manner to protect life and limit damage to property. This project will improve existing conditions through use of the proposed drainage infrastructure, water quality control ' and detention facilities. 11 VI. REFERENCES 1. Urban Storm Drainage Criteria Manual Volumes I and 2, Urban Drainage and Flood Control District, June 2001, and IVolume 3, September 1999. ' 2. City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Department of Public Works and Water Utilities, Storm Drainage Division, May, 1984. ' 3. Soil Survey of Larimer County Area, Colorado, U.S. ' Department of Agriculture, Soil Conservation Service and Forest Service, December, 1980. 4. Flood Insurance Rate Map No. 0801010192 C, Federal Emergency Management Agency, National Flood Insurance Program, March 18, 1996. 12 ' VII. APPENDICES 1. Vicinity Map Soils Data FIRMette 2. Historic Storm Drainage Calculations & Map 3. Proposed Storm Drainage Calculations & Map Runoff Routing Street Capacities ' Inlet and Sidewalk Cut Capacities Storm Sewer Sizing and Calculations Swale Calculation Detention Pond Calculations HGL Calculations 4. Erosion Control Calculations and Cost Estimate ' 5. Historic Drainage Map (insert) Proposed Drainage Map (insert) Erosion Control Plan (insert) 13 TALON ESTATES SUBDIVISION SEC 28, T 7 N, R 69 W LARIMER COUNTY, COLORADO County -- -- I Road 42C s -- 21 a,.:..�......,............ ................:.,........,,...:...............,... a -� — o: a. s Falcon Rd SITE ------ 28 =i West Horsetooth d rn - YI.......5...:...............:.....,............_...........;..... (DI ty RoQi 38E 33 {i -� -- .. ..:.._........r:............:......... LEGEND: CITYLIMIT ..,n. ,...,.., ,.......v,......,..... .,.... SECTION LINE ---------- EXISTING STREET PROPOSED STREET DRAINAGE & STREAMS — — — — ZONING LIMITS............ ................... .................... . W Swallow Road VICINITY MAP SCALE - 1 "=2000' N STEWART& j� SSO IATES ASSOCIATES DRAWN: DATE: 2KEF 2/20/06 /2 . CONSULTING ENGINEERS AND SURVEYORS SCALE: AS SHOWN 103 S. MELDRUM STREET, FORT COLLINS, COLORADO 80521 (970)482-9331 JOB #: 6146 T. 7 N. T. 6 N. LARIMER COUNTY AREA, COLORADO well drained. The surface layer and subsoil are clay loam. The underlying material is clay loam or silty clay loam. Altvan soils are deep and are on benches and ter- races. Heldt soils are deep and are on fans and valley - sides. Satanta and Stoneham soils are deep and are on terraces and uplands. The soils in this association are used mainly for irrigated crops. Some areas are used for dryfarmed crops and pasture. 16. Heldt-Renohill-Kim association Deep and moderately deep, nearly level to moderately steep, well drained clay loams and loams that formed in alluvium and in materials weathered from shale; on fans and uplands This association is in scattered areas east of the foothills in the eastern part of the survey area. Ele- vation ranges from 5,000 to 5,500 feet. Mean annual air temperature ranges from 48' to 501 F, and annual precipitation ranges from 13 to 15 inches. The association makes up about 6 percent of the survey area. It is about 20 percent Heldt soils, 20 per- cent Renohill soils, and 15 percent Kim soils. The remaining 45 percent is mainly Cushman, Fort Collins, Longmont, Midway, Thedalund, and Ulm soils. Heldt soils are nearly level to strongly sloping and are well drained. The surface layer is clay loam. The subsoil is clay loam and clay. The underlying material is clay. Renohill soils are nearly level to moderately steep and are well drained. The surface layer is clay loam. The subsoil is clay loam and clay. The underlying ma- terial is clay loam. Shale is at a depth of about 29 inches. Kim soils are nearly level to moderately steep and are well drained. The surface layer and underlying material are loam. Cushman and Thedalund soils are moderately deep, over shale or sandstone, and are on uplands. Fort Collins soils are deep and are on high terraces. Long- mont soils are deep and are in upland swales and valleys. Midway soils are shallow, over shale, and are on uplands. Ulm soils are deep and are on fans and valleysides. The soils in this association are used for irrigated and dryfarmed crops and for pasture and range. Descriptions of the Soils This section describes the soil series and mapping units in Larimer County Area. Each soil series is de- scribed in detail, and then, briefly, each mapping unit in that series. Unless it is specifically mentioned otherwise, it is to be assumed that what is stated about the soil series holds true for the mapping units in that series. Thus, to get full information about any one mapping unit, it is necessary to read both the descrip- tion of the mapping unit and the description of the soil series to which it belongs. An important part of the description of each soil series is the soil profile, that is, the sequence of layers from the surface downward to rock or other under- lying material. Each series contains two descriptions of this profile. The first is brief and in terms familiar to the layman. The second is much more detailed and is for those who need to make thorough and precise studies of soils. Color terms are for dry soil unless otherwise stated. The profile described in the series is representative for mapping units in that series. If the profile of a given mapping unit is different from the one described for the series, these differences are stated in describing the mapping unit, or they are differ- ences that are apparent in the name of the mapping unit. As mentioned in the section "How This Survey Was Made," not all mapping units are members of a soil series. Rock outcrop and Fluvaquents, for example, do not belong to a soil series but, nevertheless, are listed in alphabetic order along with the soil series. Preceding the name of the mapping unit is a sym- bol. This symbol identifies the mapping unit on the detailed soil map. Listed at the end of each description of a mapping unit is the capability unit, range site, and windbreak suitability group to which the mapping unit has been assigned. The woodland group is also listed where applicable. The acreage and proportionate extent of each map- ping unit are shown in table 1. Many of the terms used in describing soils can be found in the Glossary, and more detailed information about the terminology and methods of soil mapping can be obtained from the Soil Survey Manual (3).1 Altvan Series The Altvan series consists of deep, well drained soils that formed in mixed alluvial deposits. These soils are on uplands, high terraces, and benches and are under- lain by sand and gravel at a depth of 20 to 40 inches. Elevation ranges from 5,200 to 6,200 feet. Slopes are 0 to 9 percent. The native vegetation is mainly blue grama, western wheatgrass, sage, and cactus. Mean annual precipitation ranges from 13 to 15 inches, mean annual air temperature ranges from 481 to 50' F, and the frost -free season ranges from 135 to 150 days. In a representative profile the surface layer is gray- ish brown loam about 3 inches thick. The subsoil is about 18 inches thick; it is grayish brown loam in the upper part and brown, grayish brown, and pale brown clay loam in the lower part. Below this is about 15 inches of light brown clay loam that is underlain by brown and strong brown gravelly loamy sand. Permeability is moderate above a depth of about 36 inches and rapid below that depth. The available wa- ter capacity is high. Reaction is neutral above a depth of 12 inches, mildly alkaline between depths of 12 and 17 inches, and moderately alkaline below a depth of 17 inches. These soils are used for irrigated and dryfarmed crops and for pasture and native grasses. Representative profile of Altvan loam, 0 to 3 per- cent slopes, in native grass, near the northeast corner of sec. 23, T. 11 N., R. 68 W.: A1-0 to 3 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR Italic numbers in parentheses refer to Literature Cited, p. 172. ' 12 SOIL SURVEY sloping to strongly sloping soil is on terrace edges; fans, and benches. This soil has a profile similar to the one described as representative of the series, but the combined thickness of the surface layer and subsoil is about 18 to 19 inches. Included with this soil in mapping are some areas of soils that are more sloping and some areas of soils that have a surface layer of sandy loam. Also included are small areas of Larimer, Stoneham, and Larim soils. Runoff is medium, and the hazard of erosion is mod- erate to severe. This soil is suited to wheat and barley under dryland management. If irrigated, it is also suited to alfalfa. It is well suited to pasture and native grasses. Capabil- ity units IVe-1, irrigated, and IVe-3, dryland; Loamy Plains range site; windbreak suitability group 1. 3—Altvan-Satanta loamy, 0 to 3 percent elopes. This complex consists of nearly level soils on terraces and high benches. It is about 45 percent Altvan loam and about 30 percent Satanta loam. The soils are inter- mingled throughout the mapped areas, but Altvan loam commonly is more sloping and Satanta loam is more nearly level and is in some depressions. The Altvan soil has a profile similar to the one described as representative of the Altvan series, but the surface layer commonly is about 8 to 11 inches thick and is loam or sandy loam. The Satanta soil has a profile similar to the one described as representative of the Satanta series, but the surface layer is about 8 to 11 inches thick and is sandy loam in places. In places both soils are redder than is typical of their respective series. Included with these soils in mapping is about 15 percent Nunn soils. Runoff is slow_ to medium, and the hazards of _hind . and water erosion are slight_tQ_moderatQ. `i if�rrigated, these soils are suited to corn, sugar beets, dry beans, alfalfa, and small grain. Under dry - land management they are suited mainly to wheat, but other small grain such as barley and oats, is some- times grown. The soils are also well suited to pasture and native grasses. Capability units IIIe-3, irrigated, and IIIe-6, dryland; Loamy Foothill range site; wind- break suitability group 1. 4—Altvan-Satanta loamy, 3 to 9 percent slopes. This complex consists of gently sloping or strongly sloping soils on high terraces, benches, and fans. It is about 55 percent Altvan loam and 35 percent Satanta loam. Altvan loam is mainly more sloping, and Satanta loam is smoother. These soils have profiles similar to the ones described as representative of their respective series, but the surface layer is sandy loam and loam and the surface layer and subsoil are thinner. Many areas of both soils are redder than is typical of their respective series. Included with these soils in mapping is about 10 percent Nunn and Larimer soils. Runoff is medium to rapid, and the hazards of wind and water erosion are moderate. If irrigated, these soils are well suited to alfalfa, small grain, and pasture. Under dryland management they are suited to wheat and barley. They are also suited to pasture and native grasses. Capability units IVe-1, irrigated and IVe-3, dryland; Loamy Foothill range site; windbreak suitability group 1. Aquepts, Loamy 5—Aquepts, loamy. These nearly level or gently sloping; poorly drained soils are in depressional areas on uplands, along drainageways, and on side slopes below large canals. The surface layer is fine sandy loam, loam, or clay loam. The underlying layer is mainly loam or clay loam extending to a depth of 40 to 60 inches or more. A water table is at or near the surface in spring and summer. Included with these soils in mapping are a few small areas of Stoneham, Fort Collins, and Kim soils and Nunn clay loam, wet. Runoff is slow to medium, and the hazard of water erosion is slight to moderate. These soils are suited to pasture and native grasses. A few areas are used for hay. If drained, the soils are suited to crops. The main irrigated crops are barley, corn, sugar beets, and wheat. Capability units IIIw—I, irrigated, and Vw-1, dryland; Wet Meadow range site; windbreak suitability group 5. Aquepts, Ponded 6—Aquepts, ponded. These nearly level soils are near stream channels and drainageways. A water table is at or near the surface most of the year. The soils are extremely variable. The native vegetation is mainly cattails, sedges, and rushes. These soils offer very little grazing but are suitable for wildlife habitat. Capability unit VIIIw-1, dryland; not assigned to a range site or windbreak suitability group. Ascalon Series The Ascalon series consists of deep, well drained soils that formed in mixed wind -deposited material. These soils are on uplands and foot slopes. Elevation ranges from 4,800 to 5,700 feet. Slopes are 0 to 5 per- cent. The native vegetation is mainly blue grama and other short grasses and forbs. Mean annual precipita- tion ranges from 13 to 15 inches, mean annual air temperature ranges from 481 to 50' F, and the frost - free season ranges from 135 to 150 days. In a representative profile the surface layer is brown sandy loam about 6 inches thick. The subsoil is brown and pale brown sandy clay loam about 14 inches thick. The underlying material is pale brown or very pale brown sandy loam. Permeability is moderate, and the available water capacity is medium to high. Reaction is neutral above a depth of about 16 inches and moderately alkaline below that depth. These soils are used mainly for irrigated and dry - farmed crops. Some small areas are used for native grasses. Representative profile of Ascalon sandy loam, 0 to 3 percent slopes in a cultivated area, about 400 feet east and 650 feet south of the northwest corner of sec. 36, T. 5 N., R. 68 W.: Ap-0 to 6 inches; brown (10YR 5/3) sandy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky struc- LARIMER COUNTY AREA, COLORADO 23 4/3) moist; moderate coarse subangular blocky structure; very hard, friable; thin nearly continuous clay films or. ped faces; mildly alkaline; clear wavy boundary. B3ca-17 to 21 inches; light yellowish brown (10YR 6/4) loam, yellowish brown (10YR 5/4) moist; weak coarse suban- gular blocky structure; slightly hard, very friable; few thin patchy clay films on ped faces; violently effervescent; cal- cium carbonate as soft nodules; moder- ately alkaline; clear wavy boundary. Clea-21 to 31 inches; light yellowish brown (10YR 6/4) loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, very friable; violently efferves- cent; calcium carbonate as soft nodules; moderately alkaline; clear smooth boundary. C2-31 to 60 inches; yellowish brown (10YR 5/4) loam, dark yellowish brown (10YR 4/4) moist; massive; hard, friable; strongly effervescent; moderately alkaline. The solum ranges from 15 to 30 inches in thickness. Reaction ranges from neutral to moderately alkaline. The A horizon is loam or light clay loam 3 to 9 inches thick. The B2 horizon is heavy loam or light clay loam. Granitic material is below a depth of 40 inches in some profiles. 31—Farnuf loam, 2 to 10 percent slopes. This nearly level to strongly sloping soil is in valley fills and on side slopes. This soil has the profile described as represen- tative of the series. Included with this soil in mapping are some small areas of Rock outcrop and small areas of soils that are similar to Farnuf soil but in which granite bedrock is at a depth of less than 40 inches. Runoff is moderate, and the hazard of erosion is moderate. This soil is suited to pasture and native grasses. Capability unit VIe-6, dryland; Loamy Park range site; not assigned to a windbreak suitability group. 32—Farnuf-Boyle-Rock outcrop complex, 10 to 25 percent slopes. This moderately steep soil is on ridges and valleysides. It is about 40 percent Farnuf loam, about 30 percent Boyle gravelly sandy loam, and about 20 percent Rock outcrop. Farnuf loam is lower and more nearly level, Boyle gravelly sandy loam is higher and on ridges, and Rock outcrop is commonly steeper but is scattered throughout. The Farnuf soil has a pro- file similar to the one described as representative of the Farnuf series, but the combined thickness of the surface laver and subsoil is about 18 inches. The Boyle soil has a profile similar to the one described as rep- resentative of the Boyle series. Included with this complex in mapping is about 10 percent areas of Breece soils and areas of soils that are similar to Farnuf soil but in which granite bedrock is at a depth of less than 40 inches. Runoff is rapid, and the hazard of erosion is severe. This soil is suited to native grasses. It is also used for wildlife habitat. Capability unit VIe-5, dryland; Farnuf soil in Loamy Park range site, Boyle soil in Rocky Loam range site, and Rock outcrop not assigned to a range site; not assigned to a windbreak suitability group. Fluvaquents, Nearly Level 33—Fluvaquents, nearly level. This soil is on flood plains, low terraces, and bottom lands. The surface and underlying layers are extremely variable, range from sandy loam to clay loam, and are commonly stratified with thin layers of sand or clay. In places the underlying material is sand and gravel. A water table is commonly at a depth of less than 12 inches at some time during spring and summer, and the soil is also flooded occasionally during spring and summer. Drainage is impractical or impossible because of a lack of suitable outlets. Runoff is slight. The hazard of erosion is slight, although there is some cutting on areas near stream channels in places. This soil is suited to pasture or native grasses. A few areas are used for hay. Capability unit Vw-1, dry - land; Wet Meadow range site; windbreak suitability group 5. Fort Collins Series The Fort Collins series consists of deep, well drained soils that formed in alluvium. These soils are on ter- races and fans. Elevation ranges from 4,800 to 5,500 feet. Slopes are 0 to 9 percent. The native vegetation is mainly blue grama and western wheatgrass and some forbs and shrubs. Mean annual precipitation ranges from 13 to 15 inches, mean annual air tem- perature ranges from 48' to 501 F, and the frost -free season ranges from 135 to 150 days. In a representative profile the surface layer is light brownish gray loam about 5 inches thick. The subsoil is light brownish gray, brown, and pale brown loam about 19 inches thick. The underlying material is pale brown loam. Permeability is moderate, and the available water capacity is high. Reaction is neutral above a depth of about 8 inches, mildly alkaline between depths of 8 and 18 inches, and moderately alkaline below a depth of 18 inches. These soils are used for irrigated and dryfarmed crops and pasture. Representative profile of Fort Collins loam, 0 to 1 percent slopes, in native grass, approximately 1 block north of LaPorte Avenue on North Shields Street and 500 feet west of North Shields Street in sec. 11, T. 7 N., R. 69 W.: A1-0 to 5 inches; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; moderate fine granular structure; soft, very friable; noncalcare- ous; neutral; clear smooth boundary. 131-5 to 8 inches, light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; moderate fine subangular blocky structure parting to fine granu- lar; hard, very friable; few patchy clay LARIMER COUNTY AREA, COLORADO Runoff is slow, and the hazards of wind and water erosion are slight to moderate. If irrigated, this soil is well suited to corn, sugar beets, alfalfa, barley, and dry beans. Under dryland management it is suited to wheat and barley. It is also well suited to pasture and native grasses. Capability units IIe-1, irrigated, and IVe-3, dryland; Loamy Plains range site; windbreak suitability group 1. 36—Fort Collins loam, 3 to 5 percent slopes. This gently sloping soil is on the edges of terraces and fans. This soil has a profile similar to the one described as representative of the series, but the combined thick- ness of the surface layer and subsoil is about 20 inches. Included with this soil in mapping are a few areas of soils that are more sloping or less sloping. Also in- cluded are small areas of Stoneham and Kim soils and a few areas of soils that have a gravelly surface layer. Runoff is moderate and the hazards of wind and wa er erosion are mo era e If irrigated, this soil is suited to corn, barley, and alfalfa and, to a lesser extent, sugar beets and dry beans. Under dryland management it is suited to wheat and barley. It is also well suited to pasture and native grasses. Capability units IIIe-2, irrigated, and IVe-3, dryland; Loamy Plains range site; windbreak suitability group 1. 37—Fort Collins loam, 5 to 9 percent slopes. This strongly sloping soil is on terrace edges and the steeper part of fans. This soil has a profile similar to the one described as representative of the series, but the com- bined thickness of the surface layer and subsoil is about 18 inches. Included with this soil in mapping are a few small areas of soils that are more sloping or less sloping and a few small areas of soils that have a gravelly surface layer. Also included are small areas of Larimer, Stoneham, and Kim soils. Runoff is rapid, and the hazards of wind and water erosion are severe. If irrigated, this soil is suited to alfalfa and barley and other small grain or pasture. It is suited to pasture or native grasses under dryland management. Capa- bility units IVe-1, irrigated, and VIe-1, dryland; Loamy Plains range site; windbreak suitability group 1. Foxcreek Series The Foxcreek series consists of deep, poorly drained soils that formed in alluvium. These soils are on low terraces and bottom lands and are underlain by sand and gravel at a depth of 20 to 40 inches. Elevation ranges from 7,800 to 8,800 feet. Slopes are 0 to 3 percent. The native vegetation is mainly timothy, red - top, sedges, and other water -tolerant grasses. Mean annual precipitation ranges from 12 to 16 inches, mean annual air temperature ranges from 42' to 46' F, and the frost -free season ranges from 60 to 85 days. In a representative profile a 1-inch-thick layer of organic material is on the surface. The surface layer is mottled dark brown loam about 5 inches thick. The subsoil is mottled dark grayish brown or brown silty clay loam about 17 inches thick. The underlying ma- terial is mottled brown sandy clay loam about 14 inches thick over sand and gravel. 25 Permeability is moderate above a depth of about 36 inches and very rapid below that depth. The available water capacity is medium to high. Reaction is slightly acid above a depth of about 22 inches and neutral below that depth. These soils are mainly used for irrigated hay. Representative profile of Foxcreek loam, 0 to 3 per- cent slopes, in irrigated hayland, 400 feet south of Hohnholtz Lake Road, west of the Laramie River in sec. 7, T. 11 N., R. 67 W.: 0-1 inch to 0; undecomposed and partly decom- posed organic material. Alg-0 to 5 inches; dark brown (7.5YR 3/2) loam, dark brown (7.5YR 3/2) moist; common fine distinct dark reddish brown (2.5YR 3/4) mottles; weak moderate subangular blocky structure; hard, fri- able; slightly acid; clear smooth bound- ary. B2g-5 to 17 inches; dark grayish brown (10YR 4/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; common me- dium distinct red (2.5YR 4/6) mottles; weak medium subangular and angular blocky structure; hard, friable; slightly acid; clear smooth boundary. B3g-17 to 22 inches; brown (10YR 4/3) silty clay loam, brown (10YR 4/3) moist; common fine distinct yellowish red (5YR 4/6) mottles; weak to moderate medium subangular blocky structure; very hard, firm; slightly acid; clear smooth bound- ary. Clg-22 to 36 inches; brown (10YR 5/3) sandy clay loam, brown (10YR 4/3) moist; common medium distinct yellowish red (5YR 4/6) mottles; massive; hard, fri- able; neutral; clear smooth boundary. IIC2cag-36 to 60 inches; sand and gravel; very slightly effervescent; calcium carbonate on underside of pebbles. The A horizon is loam, clay loam, or silty clay loam 3 to 8 inches thick. It is slightly acid to neutral. The Bg horizon is loam, light clay loam, or silty clay loam. It is slightly acid to neutral. The C and IIC horizons are generally neutral or mildly alkaline. The IIC hori- zon is very slightly effervescent to strongly efferves- cent and weak accumulations of calcium carbonate are mainly on the underside of pebbles. 38—Foxcreek loam, 0 to 3 percent slopes. This nearly level soil is on low terraces and bottom lands. Included with this soil in mapping are a few small areas of Blackwell and Newfork soils. Also included are a few small areas of soils that have a cobbly and stony surface laver. Runoff is slow, and the hazard of water erosion is slight. If irrigated, this soil is suited to hay and meadow. It is also suited to pasture or native grasses. Capability unit VIw-1, irrigated; Mountain Meadow range site; not assigned to a windbreak suitability group. Gapo Series The Gapo series consists of deep, poorly drained 130 I SOIL SURVEY ' TABLE 8.Soil and water features [Absence of an entry indicates "perched." the feature is not a concern. See text for description of symbols and such terms as "rare, "brief," and Asterisk indicates mapping unit consists of two or more dominant kinds of soils. See mapping unit description for ' composition and behavior of the whole mapping unit. The symbol < means less than; > means more than] Flooding Depth to Bedrock Soil name and Hydro- logic seasonal Potential map symbol high frost ' group Frequency Duration Months water table Depth Hardness action Feet Inches ' Altvan: 1. 2------------------ B None -------- -------------- -------------- >6.0 >60 ----------- Moderate. 3, 4: ' Altvan part ________ B None ________ ______________ __________ >6.0 >60 Moderate. Satanta part ------- B None ________ ______________ ______________ >6.0 >60 ___________ ----------- Moderate. Aquepts: ' 5-------------------- 6 ____________ D D Rare -------- Frequent ____ -------------- Long ________ -------------- April -June __- 0.5-1.5 0-1.5 ---------- __________ ----------- --_---__-__ High. High. Ascalon 7. 8------------------ B None -------- -------------- -------------- >6.0 >60 ----------- Moderate. ' Bainville: '9: Bainville part ______ Epping part C D None ________ None ______________ ______________ >6.0 20-40 Rippable __ Moderate. ________ ________ ______________ ______________ >6.0 9-20 Rippable __ Moderate. '10: Bainville part ______ Keith part C B None ________ None ______________ ______________ >6.0 20-40 Rippable __ Moderate. --------- -------- -------------- -------------- >6.0 >60 ----------- Moderate. Boller: 'll: Baller part _________ Carnero part D C None ________ None ______________ ______________ >6.0 10-20 Hard _____ Low. _______ ________ ______________ _ >6.0 20-40 Hard _____ Moderate. '12: ' Boller part _________ Rock outcrop part. D None ________ ______________ ______________ >6.0 10-20 Hard _____ Low. Blackwell: 13 ___________________ D Common ____ Brief _______ May -June ___ 1.5 >60 ----------- High. Boyle: 14, 15 ________________ D None ________ ______________ -------------- >6.0 9-20 Rippable __ Moderate. 'I6, 17: ' Boyle part _________ Ratake part D D None -------- None -------------- -------------- >6.0 9-20 Rippable __ Moderate. ________ ________ ______________ ______________ >6.0 7-20 Rippable __ Moderate. Breece: 19, 20------------- B None -------- -------------- ------------- >6.0 >60 ----------- Moderate. '18, Carnero: 21------------------- C None -------- -------------- -------------- >6.0 20-40 Hard _____ Moderate. Caruso: ' 22 ___________________ C Occasional ___ Very brief ___ April- >2.0 >60 Moderate. September. ___________ Clergern: 23------------------- B None -------- -------------- -------------- >6.0 >60 ----------- Moderate. Connerton: '24, 25: Connerton part _____ Barnum part _______ B B None ________ Occasional ___ _________----- Brief _______ ______________ May -July ____ >6.0 >6.0 >60 >60 ___________ ___________ Moderate. Moderate. Cushman: 26. 27 ---------------- C None ________ ______________ -------------- >6.0 20-40 Rippable __ Moderate. Driggs : 28, 29---------------- B None -------- ---------------------------- >6.0 >60 ----------- Moderate. LARIMER COUNTY AREA, COLORADO 131 ' TABLE 8. Soil and water features —Continued E R Soil name and map symbol Hydro- logic Flooding Depth to seasonal high Bedrock Potential frost group Frequency Duration Months water table Depth Hardness action Feet Inches Elbeth: *30: Elbeth part -------- Moen part B C None -------- None -------------- -------------- >6.0 >60 ----------- Moderate. --------- ________ ______________ ______________ >6.0 20-40 Hard _____ Moderate. Farnuf : 31------------------- B None -------- -------------- -------------- >6.0 >60 ----------- Moderate. *32: Farnuf part -------- Boyle part B D None ________ None ______________ _____________ >6.0 >60 ----------- Moderate. --------- Rock outcrop part. ________ ______________ ______________ >6.0 9-20 Rippable __ Moderate. Fluvaquents: 33 ___________________ ________ Frequent ____ Brief _______ April -June ___ 0.5-25 >60 ----------- Low. Fort Collins: 34, 35, 36, 37 _-________ B None ________ ______________ ______________ >6.0 >60 ----------- Moderate. Foxcreek: 38 ___________________ C Rare -------- Brief ------- April -May -__ 0-0.5 >60 ----------- High. 3apo: 39------------------- D None -------- -------------- -------------- 3.0 >60 ----------- High. Barrett: 40------------------- 41 B Rare -------- Very brief --- -------------- >6.0 >60 ----------- Moderate. ------------------- -B None -------- -------------- -------------- >6.0 >60 ----------- Moderate. .ravel pits: 42. laploborolls: `43: Haploborolls part --- -------- None -------- -------------- -------------- >6.0 Rock outcrop part. ---------- ----------- laplustolls : 44 ------------------- -------- None ---------- ----------- *45: Haplustolls part ---- -------- None -------- -------------- -------------- >6.0 Rock outcrop part. ---------- ----------- iarlan : 46, 47 ---------------- B None -------- -------------- -------------- >6.0 >60 ----------- Moderate. leldt: 48, 49---------------- C None -------- -------------- -------------- >6.0 >60 ----------- Moderate. Leith: 50------------------- B None -------- -------------- -------------- >6.0 >60 ----------- Moderate. :ildor: 51------------------- C None -------- -------------- -------------- >6.0 20-40 Rippable __ High. *52: Kildor part -------- Shale C None ________ ______________ ______________ >6.0 20-40 Rippable __ High. outcrop part. Lim: 53, 54, 55------------- B None -------- -------------- -------------- >6.0 >60 ----------- Moderate. *56: Kim part ---------- B None ----------------------- ------------- >6.0 >60 ----------- Moderate. Thedalund part ----- C None ________ ______________ -------------- >6.0 20-40 Rippable __ Moderate. .irtley: 57 ___________________ C None -------- --------------- -------------- >6.0 20-40 Rippable __ Moderate. LARIMER COUNTY AREA, COLORADO 135 ' TABLE 9.--Building site development ["Shrink -swell" and some of the other terms that describe restrictive soil features are defined in the Glossary. See text for defini- tion of "slight," "moderate," and "severe." Absence of an entry means soil was not rated. Asterisks indicate mapping unit consists of two or more dominant kinds of soil. See mapping unit description for composition and behavior of the whole mapping unit] Soil name and Shallow Dwellings without Dwellings with Small commercial Local roads and map symbol excavations basements basements buildings streets Altvan: 1. 2 -- `3. 4: Altvan part Satanta part . Aquepts: 5. 6----------- Ascalon: 7. 8----------- Bainville: '9: ' Bainville part Epping part _ '10: Bainville part Keith part ' Baller: *11: Baller part Carnero part _ ' *12: Baller part ______. ' Rock outcrop part. Blackwell: 13 ----------------- Moderate: too clayey;cutbanks cave. Moderate: too clayey;cutbanks cave. Slight ----------- Severe: wetness. Slight ___ Moderate: shrink -swell. Moderate: shrink -swell. Moderate: shrink -swell; low strength. Severe: wetness. Moderate: shrink -swell; low strength. Moderate: depth Moderate: to rock; slope. slope. Moderate: depth Moderate: depth to rock. to rock. Moderate: depth Slight --- to rock. --- Slight ----------- Moderate: shrink -swell; slope. Severe: slope; Severe: slope; depth to rock: large stones. depth to rock; large stones. Severe: depth to Severe: rock; slope. shrink -swell; slope. Severe: slope; Severe: slope; depth to rock; depth to rock; large stones. large stones. Moderate: shrink -swell; frost action. Moderate: shrink -swell; frost action. Moderate: shrink -swell; low strength. Severe: wetness. Moderate: shrink -swell; low strength. Moderate: depth to rock; slope. Moderate: depth to rock. Moderate: depth to rock. Moderate: shrink -swell; slope. Severe: slope; depth to rock; large stones. Severe: depth to rock; shrink - swell; slope. Severe: depth to rock;large stones; slope. Severe: wetness; I Severe: wetness; I Severe: wetness; floods. floods. floods. Moderate: shrink -swell; frost action; corrosive. Moderate: shrink -swell; frost action; corrosive. Moderate: shrink -swell; low strength. Severe: wetness. Moderate: shrink -swell; low strength. Severe: slope; corrosive. Moderate: depth to rock; corrosive. Moderate: slope; corrosive. Moderate: slope; shrink -swell; corrosive. Severe: slope; depth to rock; large stones. Severe: depth to rock; shrink - swell; slope. Severe: slope; depth to rock; large stones. Severe: wetness; floods; corrosive. Moderate: shrink -swell' action. Moderate: shrink -swell; frost action. Moderate: shrink -swell; low strength. Severe: wetness; frost action. Moderate: frost action; low strength; shrink -swell. Moderate: frost action; slope; low strength. Moderate: depth to rock; frost action; low strength. Moderate: frost action; low strength. Moderate: shrink -swell; low strength. Severe: depth to rock; slope. Severe; shrink - swell; low strength; slope. Severe: depth to rock; slope. Severe: wetness; floods. Soil name and map symbol Elbeth : *30: Elbeth part _ Moen part ___. Farnuf : 31 _ *32: Farnuf part Boyle part . Rock outcrop part. Fluvaquents: 33 ----------------- Fort Collins: 34, 35-------------- 36, 37 Foxcreek: 38 ____ Gapo 39 Garrett: 40 ----------------- 41 ----------------- Gravel pits: 42. Haploborolls: *43: Haploborolls part__ Rock outcrop part. Haplustolls : 44 ----------------- '45: Haplustolls part Rock outcrop part. Harlan: 46 ----------------- 47----------------- LARIMER COUNTY AREA, COLORADO TABLE 9.—Building site development —Continued Shallow Dwellings without Dwellings with Small commercial excavations basements I basements buildings Severe: slope Severe: slope; depth to rock. Slight -------- Severe: slope . Severe: slope; depth to rock; small stones. Severe: floods Slight ------- Slight I Severe: wetness; cutbankscave; small stones. Severe: wetness. Moderate: floods. Slight __. Severe: slope Severe: slope Severe: slope Slight ----- Slight ----- Severe: slope Severe: slope Moderate: shrink -swell; low strength. Severe: slope Severe: slope Severe: floods Moderate: low strength; frost action. Moderate: low strength; frost action. Severe: wetness; floods; frost action. Severe: wetness. Severe: floods __- Slight ----------- Severe: slope Severe: slope Severe: slope Moderate: low strength. Moderate: low strength. Severe: slope . Severe: slope; depth to rock. Moderate: shrink -swell; low strength. Severe: slope Severe: slope; depth to rock. Severe: floods _ Moderate: low strength; frost action. Moderate: low strength; frost action. Severe: wetness; floods; frost action. Severe: wetness. Severe: floods Slight ______- Severe: slope Severe: slope Severe: slope Moderate: low strength. Moderate: low strength. Severe: slope Severe: slope Moderate: shrink -swell. Severe: slope . Severe: slope; depth to rock. Severe: floods Moderate: low strength; frost action. Moderate: slope; low strength; frost action. Severe: wetness; floods; frost action. Severe: wetness; corrosive. Severe: floods corrosive. Slight: corrosive. Severe: slope Severe: slope Severe: slope 137 Local roads and streets Severe: slope. Severe: slope. Moderate: frost action; shrink - swell; low strength. Severe: slope. Severe: slope; depth to rock. Severe: floods. Moderate: low strength; frost action. Moderate: low strength. I Severe: wetness; frost action. Severe: wetness; frost action. Moderate: floods. Moderate: low strength. Severe: slope. Severe: slope. Severe: slope. Moderate: low Severe: low strength. strength. Moderate: slope; Severe: low low strength. strength. \�Q ! / o \ 9L E k !| _ / p} ■| k �§ ƒ w G; .2 cc« f2 / ' \ }$3! / ( �� $: |� !! � § �� ■ !: !�||! j,/ { ui 3 G= ce co . . Gam!° .. .. gf | | ];9!! ;l8! !| 3 : : N STEWART & ASSOCIATES JOB # 6146 STORM WATER RUNOFF CALCULATIONS CLIENT: HOLTER ' TALON ESTATES SUBDIVISION DATE: 11/28/06 FORT COLLINS, COLORADO BY: KEF COMPOSITE RUNOFF COEFFICIENT CALCULATIONS FROM TABLE 3-3, CITY OF FORT COLLINS STORM DRAINAGE DESIGN CRITERIA LAND USE RUN-OFF COEFFICIENT STREETS, PARKING LOTS, DRIVES: 2y TO 10y 100y W/ FREQ FACTOR ASPHALT 0.95 1.00 CONCRETE 0.95 1.00 GRAVEL 0.50 0.63 ROOFS 0.95 1.00 LAWNS, SANDY SOIL FLAT <2% 0.20 0.25 AVERAGE 2% TO 7% 0.25 0.31 STEEP >7% 0.35 0.44 ' COMPOSITE RUNOFF COEFFICIENT 'VAS CALCULATED USING THE FOLLOWING FORMULA; n C= 21 Ci Ai /At WHERE C = COMPOSITE RUNOFF COEFFICIENT C i = RUNOFF COEFFICIENT FOR SPECIFIC AREA Ai Ai = AREA OF SURFACE WITH RUNOFF COEFFICIENT OF C i n = NUMBER OF DIFFERENT SURFACES TO BE CONSIDERED At= TOTAL AREA OVER WHICH C IS APPLICABLE; THE SUM OF ALL Ai's IS EQUAL TO At FROM TABLE 3-4 2y TO 10y STORM 100y STORM Cf = 1.00 Cf = 1.25 HISTORIC CONDITIONS BASIN # AL (LAWN) SQ FT Ac(CONC) SQ FT AR(ROOFS) SQ FT AG(GRAVEL) SQ FT AA(ASPRALT) SQ FT At SQ FT A 29,386.56 0 0 1541.04 0 30,927.60 B 72,745.20 0 0 0 0 72,745.20 C 66,211.20 0 0 0 0 66.211.20 D 192,535.20 0 0 0 0 192,535.20 E 34,193.87 0 0 10,672.93 0 44,866.80 F 9,992.85 0 0 4817.55 0 14,810.40 G 36,590.40 0 0 0 0 36,590.40 TOTAL ' COMPOSITE RUNOFF COEFFICIENTS C2 - CIO ' C100 458,686.80 SQ FT 10.53 ACRES BASIN A B C D E F G 0.21 0.20 0.20 0.20 0.27 0.30 0.20 0.27 0.25 0.25 0.25 0.34 0.37 0.25 STEWART & ASSOCIATES STORM (PATER RUNOFF CALCULATIONS TALON ESTATES SUBDIVISION LARIMER COUNTY, COLORADO JOB # 6146 CLIENT: HOLTER DATE: 11/28/06 BY: KEF CALCULATED USING RATIONAL METHOD NOTES: 1. RUNOFF COEFFICIENTS (C) ARE FROM THE URBAN STORM DRAINAGE CRITERIA MANUAL, VOLUME 1, TABLE RO-5 AND THE COMPOSITE RUNOFF COEFFICIENTS ARE FROM PREVIOUS CALCULATIONS 2. THE RAINFALL INTENSITY (I) IS FROM A DEVELOPED INTENSITY —DURATION — FREQUENCY CURVE FOR THE FORT COLLINS AREA HISTORIC CONDITIONS SUB —BASIN A AREA (AA) = 0.71 ACRES CCf = 0.21, CCfloo = 0.27, L = 42 FT, S = 2.4%, INITIAL FLOW TIME Tl = [(1.87)(1.1—CCf)(L)l/2]/(S)'/3 T1= 7.96 MINUTES T1_100 = 7.52 MINUTES TRAVEL TIME IN SWALE CALCULATED FROM FIGURE RO-1 L = 588 FT, S = 1.28%, V = 2.3 FPS TT= 4.26 MINUTES TIME OF CONCENTRATION Tc= Tl + TT USE Tc = 12.2 MINUTES Tc_100 = 11.8 MINUTES RATIONAL EQUATION (Q=CIA) C2 = .21 I2 = 2.04 Q2 = (C2)(I2)(AA) = 0.30 CFS C loo = •27 I loo = 7.21 Q 100 = (Cloo)(Iioo)(AA) = 1.38 CFS PEAK FLOW RATE MINOR STORM Q2 = 0.30 CFS MAJOR STORM Q1oo = 1.38 CFS ' SUB —BASIN B AREA (AB) = 1.67 ACRES ' CCf = 0.20, CCfioo = 0.25, L = 300 FT, S = 2.0%, INITIAL FLOW TIME TI = [(1.87)(1.1—CC f )(L)`/2 ]/(S)1/3 1 TI = 23.14 MINUTES TI_100 = 21.9 MINUTES ' OVERLAND TRAVEL TIME CALCULATED FROM FIGURE RO-1 NO CONCENTRATED FLOW TT= 0.0 MIN TIME OF CONCENTRATION TC= TI + TT USE TC = 23.1 MINUTES T c_loo= 21.9 MINUTES RATIONAL EQUATION (Q=CIA) C2 = .20 I2 = 1.53 Q2 = (C2)(I2)(AB) = 0.51 CFS C ioo = .25 I ioo = 5.47 Q ioo = (Cioo)(Iioo)(AB) 2.28 CFS MINOR STORM MAJOR STORM Q2 = 0.51 CFS Qloo = 2.28 CFS_ SUB —BASIN C AREA (AC) = 1.52 ACRES CCf = 0.20, CCfioo = 0.25, L = 230 FT, S = 1.67%, ' INITIAL FLOW TIME TI = [(1.87)(1.1—CC f)(L)1/2 ]/(S)1/3 TI = 21.51 MINUTES TI_loo = 20.3 MINUTES OVERLAND TRAVEL TIME CALCULATED FROM FIGURE RO-1 NO CONCENTRATED FLOW TT= 0 MINUTES ' TIME OF CONCENTRATION TC= TI + TT USE Tc = 21.5 MINUTES T o_Ioo= 20.3 MINUTES ' RATIONAL EQUATION (Q=CIA) C2 = .20 I2 = 1.58 Q2 = (C2)(I2)(AC) = 0.48 CFS C ioo = •25 I Ioo = 5.69 Q ioo = (Cioo)(Iioo)(AC) _2.16 CFS MINOR STORM MAJOR STORM Q2 - 0.48 CFS Qloo = 2.16 CFS SUB —BASIN D AREA (AD) = 4.42 ACRES CCf = 0.20, CCfioo = 0.25, L = 480 FT, S = 2.2%, INITIAL FLOW TIME TI= [(1.87)(1.1—CCf)(L)'/2]/(S)'/3 TI = 28.35 MINUTES TI_loo = 26.8 MINUTES OVERLAND TRAVEL TIME CALCULATED FROM FIGURE RO-1 NO CONCENTRATED FLOW TT= 0.0 MIN TIME OF CONCENTRATION Tc= TI + TT USE Tc = 28.4 MINUTES Tc_loo= 26.8 MINUTES RATIONAL EQUATION (Q=CIA) C2 = .20 I2 = 1.36 Q2 = (C2)(I2)(AD) = 1.20 CFS Cloo = •25 Iioo = 4.91 Qloo = (Cloo)(Itoo)(AD) =----5.43-- CFS MINOR STORM Q2 = 1.20 CFS MAJOR STORM Q loo = 5.43 CFS SUB —BASIN E AREA (AE) = 1.03 ACRES CCf = 0.27, CCfloo = 0.34, L = 300 FT, S = 1.7%, INITIAL FLOW TIME TI = [(1.87)(1.1—CCf)(L)'/2]/(S)'/3 TI = 22.52 MINUTES TI_loo = 20.6 MINUTES OVERLAND TRAVEL TIME CALCULATED FROM FIGURE RO-1 NO CONCENTRATED FLOW TT= 0 MINUTES TIME OF CONCENTRATION Tc= TI + TT USE Tc = 22.5 MINUTES T c_loo= 20.6 MINUTES RATIONAL EQUATION (Q=CIA) C2 = .27 I2 = 1.55 Q2 = (C2)(I2)(AE) _� 0.43 CFS C Ioo = .34 I loo = 5.65 Qioo = (Cioo)(Iioo)(AE) = 1.98 CFS MINOR STORM Q2 = 0.43 CFS MAJOR STORM Q1oo = 1.98 CFS SUB —BASIN F ' AREA (AF) = 0.34 ACRES CCf = 0.30, CCfioo = 0.37, L = 80 FT, S = 3.75%, INITIAL FLOP TIME TI = [(1.87)(1.1—CC f)(L)'/z)/(S)'/3 TI = 8.62 MINUTES TI_loo = 7.86 MINUTES ' OVERLAND TRAVEL TIME CALCULATED FROM FIGURE RO-1 L = 620 FT, S = 1.57%, V = 1.8 FPS TT= 5.7 MIN TIME OF CONCENTRATION Tc= TI + TT USE Tc = 14.3 MINUTES T 13.6 MINUTES c_100= RATIONAL EQUATION (Q=CIA) ' C2 = .30 I2 = 1.91 Q2 = (C2)(I2)(AF) = 0.19 CFS C ioo = .37 I ioo = 6.81 Qioo = (Cioo)(Iioo)(AF) =---- 0.86 _ CFS ' MINOR STORM MAJOR STORM ' Q2 = 0.19 CFS Q100 = 0.86 CFS SUB —BASIN G AREA (AF) = 0.84 ACRES ' CCf = 0.20, CCfioo = 0.25, L = 296 FT, S = 2.0%, ' INITIAL FLOP TIME Ti = [(1.87)(1.1—CCf)(L)1/2y(S)1/3 TI = 23.0 MINUTES TI_Ioo = 21.7 MINUTES OVERLAND TRAVEL TIME CALCULATED FROM FIGURE RO-1 L = 419 FT, S = 1.3%, V = 2.3 FPS TT= 3.0 MIN TIME OF CONCENTRATION Tc= TI + TT USE Tc = 26.0 MINUTES T 24.7 MINUTES c_Ioo= ' RATIONAL EQUATION (Q=CIA) C2 = .20 I2 = 1.43 Q2 = (C2)(I2)(AF) = 0.24 CFS ' Cloo = •25 I100 = 5.14 Qioo = (Cioo)(Iioo)(AF) _ 1.08 CFS MINOR STORM Q2 = 0.24 CFS MAJOR STORM Q1oo = 1.08 CFS ' DRAINAGE SUMMARY HISTORIC CONDITION BASIN AREA, SF AREA, AC Q(2), cfs Q(100), cfs A 30,928 0.71 0.30 1.38 B 729745 1.67 0.51 2.28 C 66,211 1.52 0.48 2.16 D 1929535 4.42 1.20 5.43 E 449867 1.03 0.43 1.98 F 14,810 0.34 0.19 0.86 F 36,590 0.84 0.24 1.08 TOTAL rZ89686 10.53 3.35 15.17 4/11 a r I, vlll,,li —_--_ ire^'''''/' -I', \\ 'tea."'--_--- ` a9 �` `• 00 DRIVE&AX , 1�1 '{ I _ --_ 9•' 1 I' 'lam `�qar ROAD SIDE LA�•1 SCALE , 1f ' ,7✓ - I ', ICI' I ii r FAG' �'/ r1"1MN i LAIERIAL 141' 4.42 m*NI �.�. V D`:F` -A* �N Iro ADS o.PIP1YEI STEF1 EDGE OF 1rf ADS,r e �p` _-_ _ _ _- ---_- --T NEAR WA11-�••--�'----- -_ __-'�________-7 __r__ ____�, tr/ SRil PPE-/ I ,s 11' II LI P fro RCP ^ FALCON ROAD \\ -try � � �•. NOTE STORM WATER RUNOFF IS CURRENTLY NOT DETAINED AND RELEASES INTO EXISTING ROADSIDE SWALE$ AND PLEASANT VALLEY & LAKE CANAL FW2 TRACT A NORTHEAST 1 /4 OF SECTION 28 TOWNSHIP 7 NORTH, RANGE 69 WEST LARIMER COUNTY, COLORADO GENERAL NOTES: 1. SITE CONTOURS.ARE BASED ON NGVD 29 SURVEY DATUM 2i EXISTING CONTOURS ARE SHOWN AT ONE F00T INTERVALS 3! SITE IS PRESENTLY USED AS FLOOD A I IRRIGATED PASTURE I I�- SCALE - 1 "=50' 50 0 so 100 MANIC SCALE - FEET City of Ft Collins B.M. No. 6-02 Elevation m 5113.70 1/2 mile North of Horsetooth Road on the East aide of 3040 South Taft Hill Road on the Northeast corner of a storm inlet EXISTING DRAINAGE CONDITIONS DRAINAGE LEGEND SURFACE FLOW DIRECTION (CONCENTRATED FLOW) SURFACE FLOW DIRECTION (SHEET FLOW) A A=SUB-BASIN DESIGNATION B=AREA IN ACRES BC. C=COMPOSITE RUNOFF COEFFICIENTS Ca = (2year event) CvII _ (100year event) QD=DESIGN POINT DESIGNATION SUMMARY RUNOFF TABLE BASIN DESIGN POINT' CONTRIBUTING AREA (ACRES) 0(2).cfs 0(100).cfe A 1 0.71 0.30 1.38 B 2* 1.67 0.51 2.28 C 3* ' 1.52 0.48 2.16 D 4* 4.42 1.20 5.43 E 5 1.03 0.43 1.98 F 6 0.34 0.19 0.86 G 6 0.84 0.24 1.08 IUIFL ,U.S3 &M 15.17 s = SHEET FLOW. NO DEFINED CONCENTRATED POINT LEGEND: SUB -BASIN BOUNDARY" ------------ SITE BOUNDARY/PROPERTY LINE - EXISTING MINOR CONTOUR ------------------------- EXISTING MAJOR CONTOUR -------- too -_-_--- CANAL CENTERUNE -- - -- CENTERLINE OF ROAD — - - -- EDGE OF GRAVEL ROAD ----------------------- 1 `V) x Q U � 0 V) Qa%y V f/) Q w ! "V z ' w I Ch I E z Lv r o = U t V / [ t, �I i N Z O N IY 0 Q Z O W V° Z_ Z O E— +a xl�x oas 6146 t2/13/� slm NIe6Flt 1 � 2 c i City of Fort Collins Rainfall Intensity -Duration -Frequency Table for using the Rational Method (5 minutes - 30 minutes) Figure 3-1a Duration (minutes) 2-year Intensity in/hr 10-year Intensity in/hr 100-year Intensity in/hr 5.00 2.85 4.87 9i95 6.00 2.67 4.56 931 7.00 2.52 4.31 OiOu 8.00 2.40 4.10 8138 9.00 2.30 3.93 8'03 10.00 2.21 3.78 712 11.00 2.13 3.63 7,42 12.00 2.05 3.50 1 7.16 13.00 1.98 1 3.39 6.92 14.00 1.92 3.29 6.71 15.00 1.87 3.19 6.52 16.00 1.81 3.08 6.30 17.00 1.75 2.99 6.10 18.00 1.70 2.90 5.92 19.00 1.65 2.82 5.75 20.00 1.61 2.74 5.60 21.00 1.56 2.67 5.46 22.00 1.53 2.61 5.32 23.00 1.49 2.55 5.20 24.00 1.46 2.49 5.09 25.00 1.43 2.44 4.08 26.00 1.40 2.39 4.87 27.00 1.37 2.34 4.78 28.00 1.34 2.29 4.69 29.00 1.32 2.25 4.60 30.00 1.30 2.21 4.52 City of Fort Collins Rainfall Intensity -Duration -Frequency Table for using the Rational Method (31 minutes - 60 minutes) Figure 3-1b [Itj 2-year Intensity in/hr 1.27 1.243.00 10-year Intensity in/hr 2.16 r jin/,hr 1.22 2.08 4.24 34.00 1.19 2.04 4.16 35.00 1.17 2.00 4.08 36.00 1.15 1.96 4.01 37.00 1.13 1.93 3.93 38.00 1.11 1.89 3.87 39.00 1.09 1.86 3.80 40.00 1.07 1.83 3.74 41.00 1.05 1.80 3.68 42.00 1.04 1.77 3.62 43.00 1.02 1.74 3.56 44.00 1.01 1.72 3.51 45.00 0.99 1.69 3.46 46.00 0.98 1.67 3.41 47.00 0.96 1.64 3.36 48.00 0.95 1.62 3.31 49.00 0.94 1.60 3.27 50.00 0.92 1.58 3.23 51.00 0.91 1.56 3.18 52.00 0.90 1.54 3.14 53.00 0.89 1.52 3.10 54.00 0.88 1.50 3.07 55.00 0.87 1.48 3.03 56.00 0.86 1.47 2.59 57.00 58.00 0.85 0.84 1.45 1.43 2.96 2.92 59.00 0.83 1.42 2.89 60.00 0.82 1.40 2.86 I STEWART&ASSOCIATES 103 S. MELDRUM, FORTjCOLLINS, CO 80521 Consulting Engineers and Surveyors PH. 482 9,3tj31 FAX 482-9382 By: pr\f" Date: Z D I OIo Client: kS o� AE ti 4-cy- Sheet No. of I Project: lr, Subject: cc�z 1 1 I4a CCUz-�� ©�� Ctoo 61s(o I C, IbSCC 4 o:a 1 cc�Z a i ��a � � a C2-to d ,�15 Cc�,.lpos ��-e. 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'P � (!(.' )Cdc f!4 �J = C).fs 1 ' i (Ylay S�ceQa -� Cco�r, � Cov.�c-olS �� 110 e�rh oVerQ' �I =.75 17, = 19r7'I =Tki =LA1.91, otLp 2 0 Q 4t2- C�S FeAxtior cl o r o lvs Q = 8 ,zc((a.4 Q�s i M�or S5Voc rr` '\ -� Ce over Cron o � atv�VL ca) V7L assut.>4a 5=o,do5 Q�� �►,a =o.�o 14,�cc�c-Lq - co Cco'xn P� UlD sPre�d -- i CAS Ve- 4CO CLL60 Lvca1 ZJrct� 0.56A •Ia v` LJtfi.n ovur V.%�[aa.T.C.: a. a.,, fill) r� I•� 7_c� (_1Cdvd606N _�dcccTr r 2.0 10000 n IS .eu.+•t[[ co[rrlcl[nr IM AaR., a .10 9000 ro•.ULA .••.OR.IATE To MATERIAL I. 8000 •or,c. or c.... E, 7000 t is .acn.ocAL or CROSS Lon .06 6000 .Pta[SCL. • s ••acctol.,s n.a• .07 5000 r.Mt nM. EQUATION n.T .80 .O6 4000 .70 EXAMPLE rstt eas.to u.CSI tL .05 3000 ,I.C.I S • O.Os ? o 0 .60 t\ 1000 900 800 Tao rw 600 C a 500 a' O 400 ~ a 300 200 100 90 80 70 6c 40 30 EACI Ee. t. t.] N „ n oe [/n.Itoe � .04 .50 C.� 70 LL' aC LL reel M 4a Cr3 _— .03 - .40 _ , — ---- -7 _ — Z .30 _ O .-.— \ v a 3 N .. .20 W Z INST NUCTI014 Ur J _2 Rol O x .07 W 10_ I. CO..[CT [/n •.TIa .ITS SLID., IS, Q 07 .+o co++tcr U.Sc... It IMI .•,. 03 Z .008 ov r. SET r.0 sc *.o LI+Cs Nvsr V � i Q LTr•Sar .T TUBA,+c al+t ro. (/) ROOT (n .10 sowno. V W c o.nc*c .oT .006 a .08 [. ra• S..uo. ' .005 w ......ro C..+Nta II4 O 0 .07 .S Sna.. us, SCAM,.... I .004 06 tyt cr a- O .05 —• O ['04 S ro on [•.I.[ �a--� .003 Cn as<•..,c a, 1 i Cn ui ro•r•a. O• c....n I :;L T, oCrn.INa ar•r. O TO. TOTAL I -SC ... CE IN .002 [NTI•t SECTION • T.EN USE Na AQ4•✓. re oc rC•.INc O• . s[c T.O. . 'T. oC•r. ' IU� r . ro ETC----[ ono-.•o[ ..COARa S", SECTro• - I roa Lo. I•SnUc rIM+ s I rT re O•r.,N Q.SC...C[ IR — .001 1— t�i SECTION . AT .SSUACe •[�uv'I oc•,+ ) p Ms,... a 'a• From BPR SLC-C ..rIM al.,. ; T.C. a, . a, . 0. Figure 4-1 NONOGRAPH FOR FLOW IN TRIANGULAR GUTTERS. (From U.S. Dept. of Commerce, Bureau of Public Roads, 1965) U 03 Q rom MAY 1984 4-3 DESIGN CRITERIA (Based on Regulates cntena for Maximum Allowable Flow Deptn anal spread) Project: Talon Estates I Inlet ID: - I TRACK SBAC_- H Y cueB d e TCROWN T. TMAT w-� T% Street .�,/ Crown \QW .�/.� \g3 mum Allowable Width for Spread Behind Curb Slope Behind Curb (leave blank for no conveyance Credit behind curb) ring's Roughness Behind Curt of Curb at Gutter Flow Line :e from Curb Face to Street Crown Transverse Slope Longitudinal Slope - Enter 0 for sump condition ig's Roughness for Street Section Allowable Water Spread for Minor & Major Storm Allowable Depth at Gutter Flow Line for Minor & Major Storm Flow Depth at Street Crown (leave blank for no) er Cross Slope (Eq. ST-8) er Depth without Gutter Depression (Eq. ST-2) at Depth with a Gutter Depression vable Spread for Discharge outside the Gutter Section W (T- W) at Flow to Design Flow Ratio by FHWA HEC-22 method (Eq. ST-7) barge outside the Gutter Section W, Carried in Section Tx barge within the Gutter Section W (Qr - Q, ) barge Behind the Curb (e.g., sidewalk, driveways, & lawns) imum Flow Based On Allowable Water Spread r Velocity Within the Gutter Section Product: Flow Velocity Times Gutter Flowfrne Depth Ta,CK = 24.8 ft SBACK = 0.0200 ft. van. / ft. hortz n,ACK = 0.0350 HcuRe = 4.75 inches TCROWN = 15.0 ft a = 0.76 inches W = 2.58 ft Sx = 0.0200 ft. vert. / ft. hortz So = 0.0050 ft. vert. / ft. hortz nsraEr = 0.0160 T. = dnux = Sw = y= d= Tx = Eo = Qx = Qw= OBACK = Or= V= V•d = oretical Water Spread TTM = oreticel Spread for Discharge outside the Gutter Section W (T - W) Txni = ar Flow to Design Flow Ratio by FHWA HEG-22 method (Eq. ST-7) Ea - oretical Discharge outside the Gutter Section W, carried in Section Tx rM Ox ni = ial Discharge outside the Gutter Section W, (limited by distance TCRCWM) OK = tiarge within the Gutter Section W (Qa - Qx) Ow = barge Behind the Curb (e.g., sidewalk driveways, & lawns) QUACK = it Discharge for Major & Minor Storm Q = ✓ Velocity Within the Gutter Section V = Product: Flow Velocity Times Gutter Flowfine Depth V•d = ie-Based Depth Safety Reduction Factor for Major & Minor (d > 6") Storm R = : Flow Based on Allow. Gutter Depth (Safety Factor Applied) Qa = Wtant Flow Depth at Gutter Flowline (Safety Factor Applied) d = ultant Flow Depth at Street Crown (Safety Factor Applied) dCRCWi4 _ Minor Slonn Major Storm 10.9 1 15.0 4.751 10.70 7( 0.0445 10.0445 2.62 1 3.60 3.38 1 4.36 8.3 1 12.4 0.578 1 0.441 1.0 I .3.0 1.4 1 2.4 0.0 1 0.0 2.5 1 _6.4 4.11 1 5.0 1.21 1 1.8 Minor Storm Major Storm fl inches X=yes fttft inches inches ft cis cis cis cis fps cis ds cis cis cis fps dfs inches inches Minor Storm iMa'or Storm Towable Gutter Capacity Based on Minimum of QT or ci, ovb. _ 2.5 { 61.8 cfs STORM max. allowable capacity OK - greater than flow given on sheet'Q-Peak' STORM max. allowable capacity OK - areater than flow aiven on sheet'O-Peak' 16.6 1 41.4 14.0 _ 1 38.8 0.402 1 0.166 4.2 1 63.1 4.2 1 40.5 2.8 ( 12.6 0.0 1 _ 8.7 7.0 I 61.8 5.4 9.7 2.1 8.7 1.00 1.00 .0 t1161.80 UD-Inlet.xls, Q-Allow 1214/2006, 3:53 PM .3 2 0 0 CF= s•06 0 B N -F I LS :0.4% F:0.5 r� I I1 I Rill I BELOW ALLOWABLE STREET I MINIMUM GRAOE I Ii 1 i a - e: 2 4 6 8 10 12 14 SLOPE OF GUTTER (%) Figure 4-2 REDUCTION FACTOR FOR ALLOWABLE GUTTER CAPACITY Apply reduction factor for applicable slope to the theoretical gutter capacity to obtain allowable gutter capacity. . (From: U.S. Dept. of Commerce, Bureau of Public Roads, 1965) MAY 1984 4-4 DESIGN CRITERIA INLET IN A SUMP OR SAG LOCATION Project = Talon Estates Inlet ID = Dips I .I, Lo (C)- I H-Curb H-Vert w WP W ! Lo (G) I Type of Inlet Type = Local Depression (additional to corrtbwous gutter depression's' from'Q-ABow/) a� _ Number of Unit Inlets (Grate or Curb Opening) No = Grate Information Length of a Unit Grate L, (G) = Width of a Unit Grate W. = Area Opening Ratio for a Grate (typical values 0.15-0.90) A„ �, = Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cr (G) = Grate Weir Coefficient (typical value 300) C„ (G) = Grate Orifice Coefficient (typical value 0.67) C, (G) = Curb Opening Information Length of a Unit Cum Opening L, (C) = Height of Vertical Curb Opening in Inches H„a = Height of Curb Orifice Throat in Inches Hrneu = gle of Throat (see USDCM Figure ST6) Theta = Side Width for Depression Pan (typically the gutter width of 2.58 feet) W, = Clogging Factor fora Single Curb Opening (typical value 0.10) Dr (C) = Curb Opening Weir Coefficient (typical value 2.30-3.00) C. (C) = Curb Opening Orifice Coefficient (typical value 0.67) C. (C) = grog Coefficient for Multiple Units Coef = ging Factor for Multiple Units Clog = e as a Weir Depth at Local Depression without Oogging (0 cis grate, 3.83 cis curb) CIA = Row Used for Combination Inlets Only da,p,,, _ Depth at Local Depression with Clogging (0 cis grate, 3.83 cls curb) cl , _ Row Used for Combination Inlets Only d=,ea = e as an Office Depth at Local Depression without Clogging (O cis grate, 3.83 cis curb) dm =, Depth at Loral Depression with Clogging (0 cis grate, 3.83 cis curb) d„ =', utffna Gutter Flow Depth Outside of Local Depression d_ , -= Clogging Coefficient for Multiple Units Clogging Factor for Multiple Units Curb as a Weir, Grate as an Orifice Flow Depth at Local Depression without Clogging (0 cis grate, 3.83 cis cum) Flax Depth at Local Depression with Clogging (0 cis grate, 3.83 cis curb) Curb as an Orifice, Grate as an Orifice Flow Depth at Local Depression without Clogging (0 ds grate, 3.83 cis pub) Flow Depth at Local Depression with Clogging (0 cfs grate, 3.83 cis curb) Resulting Gutter Flow Depth Outside of Local Depression Wet Length Inlet Interception Capacity (Design Discharge from Q-Peak) Ifarlt Gutter Flow Depth (based on sheet Q-Allow geometry) ham Street Flow Spread (based on sheet Q-Allow geometry) hart Flow Depth at Street Crown MINOR i MAJOR COOT Type R Ciub 2.00 jinches 7A3 3 I MINOR MAJOR WA I WA feet WA i WA feet WA I N/A WA N/A WA I WA WA I WA MINOR MAJOR 5.00 I 5.00 feet 3.75 - I 3.75 inches 3.70 I 3.70 inches 63.4 I 63.4 degree 2.58 I 2.58 feet D10 0.10 WA N/A f N/A WA inches inches inches inches MINOR I MAJOR Cost= 1.31 I 1.31 Clog = 0.04 I 0.04 MINOR I MAJOR dM = 2.77 i 7.66 inches d„ =1 Z861 I 7.89 inches MINOR ! MAJOR dy= 1.94 C6=1 97 L=1 d = T= 15.0 feet cts In, fL>TCm" 17.6 0.86 I 6.23 1.6 I 15.0 UD-Inlet DP4Jds, Inlet In Sump 6/25/2007, 10:46 AM 1 1.0 12 5 II 10 4 .9 8 10 6 3 9 0 4 \ 2 u_ -H � 7 8 cr w w 3 ���� z I.5 z o 1.0 0 z 9 5 5.5 v-.B- __—___—� .8 W .6 w 5 = z o .7 a .4 z z .4 z a c=� 6 4.5 z o 3 w v u_ ^ o .0 .5 Co 4 2 = F Z z - 'DP 0 ' w. 3 3.5 w w r .4 o a J .I w . %4 a-- 13.6 ow wo p 08 .25 3 0 06 .3 y = o c� w Z 1 = T rc .04 .25 2.5 w w .2 } .03 c 02 wo .2 a 2 a 15 .01 0 .15 L w 0 yo 0=2, h ¢ .10 .1 1.2 Figure 5-2 ' NOMOGRPAH FOR CAPACITY OF CURB OPENING INLETS IN SUMPS, DEPRESSION DEPTH 2- Adapted from Bureau of Public Roads Nomograph iMAY 1984 5-10 DESIGN CRITERIA $TEWART$,�,SSOCIATES 103 S. MELDRUM, FORT COLLINS, CO 80521 PH. 482-9331 FAX 482-9382 Consulting Engineers and Surveyors By: X-IN 01 Date: O't Client: MCLC�kAd- 110 A'e' Sheet No. of Project: gk6n E4tc�e-S Subject: 0100 3 CA = CLtA C=3.0 14 = a,IS = a.c C-Aewaft, C%J _ i3 L Q= 3 (13),d`� = q.zlQj s Circular Pipe Flow Project: Talon Estates Pipe ID: DP4 to Pond i Tc s• ' , ' / Y Invert Slope Manning's n-value Diameter gn discharge now area Flow wetted perimeter Central Angle flow capacity Central Angle (0<Theta<3.14) r area width led perimeter f depth r velocity Aarge nal Depth Froude Number Central Angle (0<Theta-c<3.14) :al flow area :al top width :al flow depth :at flow velocity cal Depth Froude Number So = 0.0100 ft(ft n = 0.0130 D = 24.00 inches Q = 17.6 cfs Af= 3.14 sgft j Pf = 6.28 ft Theta = 3.14 red Qf = 22.7 cfs 1 Theta = 1.90 red An= 2.21 sgft Tn = 1.89 ft Pn = 3.80 ft Yn = 1.32 ft Vn = 7.97 fps On = 17.6 cfs Fr„= 1.30 i Theta-c = 2.11 rad Ac = 2.55 sq ft Tc= 1.72 ft Yc= 1.51 ft Vc = 6.91 fps Frc = 1.00 UD-Culvert-DP4 to Pond.xls, Pipe 6/25/2007, 10:46 AM Project: Channel ID: Critical Flow is - Trapezc Talon Estates Swale to Pond Channel F YO Y 1� 1 w Zl e-----B------a Z2 :)m Width B = 2.00 ft Side Slope Z1 = 4.00 ft/ft t Side Slope Z2 = 4.00 ft/ft gn Discharge Q = 5.26 cfs Flow Depth Y = 0.45 ft Flow Area A = 1.68 sq ft Top Width T= 5.56 ft Hydraulic Depth D = 0.30 ft Flow Velocity V = 3.13 fps Number Fr= 1.00 Wetted Perimeter P = 5.67 ft Hydraulic Radius R = 0.30 ft (min) Specific Energy Esc = 0.60 ft' d on the Critical Flow Area Yoc = 0.15 ft (min) Specific Force Fsc = 0.65 kip UD-Channels.xls, Basics 3/14/2007, 1:39 PM 103 S. UM, FORT STEWART$,A SSOCIATE$ PH. 482-93311RFAX 482-9380LLINS, CO 80521 Consulting Engineers and Surveyors (( I By: a\"-N Date:. Z C Client: k1CAV�,e, Sheet No. Hof Project: TOA pv\ E i Subject: caa� (Or (Yl �CoSk v1S = (o .53 - yC ik1C'4o(•,C, qow 7-; GAS I S \Ae �*� = Q :.SLO py�rt5 �c r r-etQc�Se. = 3• � CAS � �—e�,e�S� c��-e.. = 0.3`=�� C�S IC�Gc� I I MAJOR DETENTION VOLUME BY FAA & MODIFIED FAA METHOD (See USDCM Volume I Runoff Chapter for description of method) Project Talon Estates Basin ID: 1 (For catchments less than 160 acres only. For larger catchments, use hydrograph routing method) (Note: for catchments larger than 90 acres, CUHP hydrograph and routing are recommended) The user must fill in all of the blue cells for these sheets to function. emend Drainage Imperviousness anent Drainage Area ivelopment NRCS Soil Group n Period for Detention Control of Concentration of Watershed able Unit Release Rate (See Table A) hour Precipitation In Rainfall IDF Formula I = C11' P1I/(C2NTc)•C3 icient One icient Two icient Three 1 = 41.46 percent A= 9.7200 acres Type = B A B, C, or D T = 100 years (2, 5, 10, 25, 50, or 100) TG= 27 minutes q = 0.36 cfs/acre P, = 2.66 inches C, = 28.50 Ce= 10.00 C3 = 0.79 'Coefficient C= 0.50 Peak Runoff Op -in= 22.87 ch; ble Peak Outflow Rate Op -out = 3.50 crs of OpouUOp-in Rafio= 0.15 Determination of MAJOR Detention Volume Using FAA & Modified FAA Method 5 11 Enter Rainfall Duration Incremental increase Value Here e.. 5 for SMmutes Rainfall Duration minutes (input) Rainfall Intensity inches /hr (output) Inflow Volume cubic feet (output) Average Outflow (FAA, cfs) (output) Outflow Volume (FAA, cf) (output) Storage Volume (FAA, cf) (output) Adjustment Factor (Modified) (output) Average Outflow (Mod, cfs) (output) Outflow Volume (Mod, cf) (output) Storage Volume (Mod, cf) (output) 5 9.60 13,991 2.04 613 13.378 1.00 3.50 1,050 12,941 10 7.65 22,294 2.04 1,227.. ,. 21.067 "1.00 3.50 2,100 20,194 15 6.41 28.036 2.04 1.840 26,196 - 1.00 - 3.50 - 3j149 24,887 20 5.55 32,367 2.04 2,453 - . 29,914 1.00 3.50 4,199 28,168 25 4.91 35,820 2.04 3,067 - 32,753 1.00 3.50 5,249 30,571 30 4.42 38.681 - 2-04 - 3,680 35,001 0.95 3.32 5,979 32,701 35 4.03 1 41,118 204 - 4,293 36,824 0.89 3A0 6,504 34,613 40 3.71 43,239 2.04 4,907 38,332 - 0.84 2.93 7.029 36.209 45 - 3.44 45,115 .2.04 5,520 39,595 0.80 2.80 7.554 37,561 50 3.21 46,798 2.04 6.133 40,665 0.77 2.69-- 8.079 38,719 55 3.01 48,324 204 6,747 41,577 - 0.75 '2.61 8.604 39,720 60 2.84 49.719 2.04 7,360 42,359 0.72 2.54 9.129 40,590 65 2.69 51,005 2.04 7,973 43,032. 0.71 2.48 9,654 41,351 70 2.56 52,198 2.04 8.587 43,612- 0.69 2.42 10,178 42,020 75 2.44 53,311 2.04 9,200 44,111 0.68 2.38 - 10,703 42,608 80 2.33 54,355 - 204 9,813 44,542 _ 0.67 2.34 11,228 43,126 65 2.23 55,337 204 _ 10,426 44,911' 0.66 2.30 11,753 - 43.584 90 2.14 56,265 2.04 11,040 45,226 . 0.65 2.27 12,278 43,987 95 2.06 57,146 2.04 - 11 A53' 45.492 0.64 2.25 12.803 44,343 100 1.99 57.983 2.04 12.266 :, 45,716 0.63 2.22 13,328 44,655 105 192 58.781 204 12,880 45,901 0.63 .2.20 -13,853 44,928 110 1.86 - 59,544 2.04 13,493 ' 46,051 0.62 2.18 14.378 45,166 115 1.80 60,275 2.04 14,106 46,169 0.62 216 14.902 45,373 120 1.74 60,977 2.04 14,720 46,257 0.61 2.14 15,427 45,549 125 1.69 61,652 2.04 15,333 ' 46,319. 0.61 2.13 15,952 1 45,700 130 1.64 62,302 2.04 - 15,946 '46,355 0.60 - 2.11 16.477 45.825 135 1.60 62,929 _ 2.04 16,560 46,369 0.60 2.10 17,002 45,927 140 1.56 63,535 2.04 17,173 46,362 _ 0.60 2.09 17,527 46,008 145 1.52 64.122 2.04 17,786 46,335 0.59 2.07 18,052 46,070 150 1.48 64,690 204 18,400 46,290 0.59 2.06` 18,577 46,113 155 1.44 65,241 204 19,013 46,228 0.59 2.05' 19.101 45,139 160 1.41 65,775 204 - 19,626 46,149 0.58 2.04 19,626 46,149 165 1.38 66,295 2.04 20,240 ' 46,056 0.58 - 2.04 20,151 46.144 170 1.35 66,801 2.04 20,853 ' 45,948 .. 0.58 2.03 20,676 46,125 175 132 1 67.293 204 21,466 45,827 0.58 2.02 21.201 _ 46,092 180 1.29 67,773 204 22,080 45,693 0.57 2.01 21,726 46.047. 185 1.26 68,241 204 22,693 - - 45,548 0.57 2.00 - 22,251 45,990 FAA Major Storage Volume (cubic R) = FAA Major Storage Volume (acre-R) _ 46,369 Mod. FAA Major Storage Volume (cubic h.) = Mod. FAA Major Storage Volume (acre-ft.) =F 46,149 1.0645 1. 5554 UD-Detention 1.As, Modified FAA __............. ....,.,......... ........... �. ..,..ate.... ,.y,. .�...,� 6252007.10:49 AM MAJOR DETENTION VOLUME BY FAA & MODIFIED FAA METHOD (See USDCM Volume I Runoff Chapter for description of method) Project: Talon Estates Basin ID: 1 Inflow and Outflow Volumes vs. Rainfall Duration Intersection of Modified and FAA Outflow Plots Is at maaimum detention volume 80,000 70,000 60,000 50,000 m m LL U n tj 40,000 E E 0 30,000 20,000 10,000 0 0 20 40 60 80 100 120 140 160 180 200 Duration (Minutes) —Inflow Volume -A—Modified Outflow Volume -*—FAA Outflow Volume UDFCD DETENTION VOLUME ESTIMATING WORKBOOK Version 2.01, Released August 2006 UD-Detention 1 As. Modified FAA 6tlSQ007, 10:49 AM Talon Estates Pond Volume 6/22/2007 Elevation ft Area ftz Volume ft3 Cumulative Volume ft3 Cumulative Volume ac-ft 2.55 0 0 0 0.00 3 1684 253 253 0.01 4 13166 6520 6772 0.16 5 17799 15424 22197 0.51 6 23096 20390 42587 0.98 7 28030 25523 68110 1.56 11 Design Procedure Form: Extended Detention Basin (EDB) - Sedimentation Facility 11 I �1 Designer. Company: Date: Project: Location: Mary Mateo Stewart & Associates January 31, 2007 Talon Estates FL Collins, CO 1. Basin Storage Volume I, = 41.46 % A) Tributary Area's Imperviousness Ratio (i = la/ 100) i = 0.41 B) Contributing Watershed Area (Area) Area = 9.720 acres C) Water Quality Capture Volume (WQCV) WQCV = 0.18 watershed inches (WQCV =1.0`(0.91'11_1.19.12+0.78'p) D) Design Volume: Vol = (WQCV / 12) `Area' 1.2 Vol = 0.1785 acre-feet 2. Outlet Works A) Outlet Type (Check One) X Orifice Plate Perforated Riser Pipe Other. B) Depth at Outlet Above Lowest Perforation (H) H = 2.00 feet C) Recommended Maximum Outlet Area per Row, (A,) A, = 0.4 square inches D) Perforation Dimensions: I) Circular Perforation Diameter or D = 0.750 inches ii) Width of 2" High Rectangular Perforations W = inches E) Number of Columns (nc, See Table 6a-1 For Maximum) nc = 1 number F) Actual Design Outlet Area per Row (A,) A, = 0.4 square inches G) Number of Rows (nr) nr = 6 number H) Total Outlet Area (A,) A,r = 2.6 square inches 3. Trash Rack A) Needed Open Area: A, = 0.5' (Figure 7 Value)' A, A, = 93 square inches B) Type of Outlet Opening (Check One) X < 2" Diameter Round 2" High Rectangular Other: C) For 2", or Smaller, Round Opening (Ref.: Figure 6a): i) Width of Trash Rack and Concrete Opening ^wc) from Table 6a-1 Ww„c = 6 inches ii) Height of Trash Rack Screen (HT .H-m = 54 inches 1 Of UD-BMP-EDB.xIs, EDB 1/31/2007, 10:33 AM 1 STEWART$,LSSOCIATES 10 82 9 31 LDRFM, FORgT COLLINS, CO 80521 PH.Consulting Engineers and Surveyors IIe- By: MfY1 Date: ► O(c Client: _W 0AgX okr Sheet No. --J— of Project �� trnn E S e.-% Subject: 4. ► 4er QUA � 44 Pln4e l_ ie" Wce = 4 I C' (asp = 3.3 al, .5- 0 W u 3x3 -1)ay� I coluvv,n o � (a r mtA p .-1," -e 6 tes 0 z' 0 0 0 Circular Pipe Flow 11 11 11 11 11 11 11 11 Project: Talon Estates Pipe ID: Pond Outlet Pipe V I Y Invert Slope So = 0.0015 ft/ft Manning's n-value n = 0.0130 Diameter D = 18.00 inches ign discharge Q = 3.4 cfs -flow Capacity (Calculated) flow area Af = 1.77 sq ft flow wetted perimeter Pf = 4.71 ft Central Angle Theta = 3.14 rad -flow capacity Qf = 4.1 cfs :ulation of Normal Flow Condition Central Angle (0<Theta<3.14) Theta = 1.96 rad r area An = 1.30 sq ft width Tn = 1.39 ft ted perimeter Pn = 2.94 ft i depth Yn = 1.04 ft i velocity Vn = 2.58 fps :harge Qn = 3A cfs mal Depth Froude Number Fr = 0.47 :ulation of Critical Flow Condition Central Angle (0<Theta-c<3.14) Theta-c = 1.50 rad al flow area Ac = 0.81 sq ft al top width Tc = 1.50 ft al flow depth Yc = 0:70 ft ml flow velocity Vc = 4.16 fps cal Depth Froude Number Fri = 1.00 UD-Culvert-Pond Outlet.xls, Pipe 12/12/2006, 9:22 AM STEWART&ASSOCIATES Consulting Engineers and Surveyors 103 S. MELDRUM, FORT COLLINS, CO 80521 PH. 482-9331 FAX 482-9382 By: M(Yl `tDate: 2 2 Client: KW.-t nx 1 04� Sheet No. of � Project:^[ l p,A G SFc. S Subject: .Ytt. ova is} AA S , I\AY A � Q 10o Z5, -Ile) cis 1= o ,5' STEWART&ASSOCIATES 10 82 93 DRUM,FAX FORT gOLLINS, CO 80521 PH.Consulting Engineers and Surveyors 1, By: (Y\m Date: _ Client: NsaC1w--�- `A4er Sheet No. —L of ._ .-- Project: I L ov1 Subject: ko Lis - S+n}ryv Q=3.ck% - = Q'I = Z r1\A.%%NAe -�o 1t1%1ek' C4(6-") CLIP`) TWA tE GE z.'7o' Idc(m' 3,1{ Z 7� z•7� 3,u7. Z.3$ 3.800 3.44i, 3.51 4ccddl h LM = KncDcd c�cP�a �� K,= o,► C5 I �t -5'h p� I ,� �� \�� �,., C> -- G. 3-3t.5 5 J 3.eo `3e p v - z .S2s Q<. ,72 Z.3e6 3,516 4$ .01 z.vs 3.`IS 3.5-7 C 8 = 1 l/Y= 0,to STEWART&ASSOCIATES 10 S. 9 DR331 F , FORT 8OLLINS, CO 80521 Consulting Engineers and Surveyors 1�jj Vf � - By: r�YIM -1 Date: L-Client: c� bto`te( Sheet No. of Z' Project I6Abr.% Subject: k(2f S� vy� i�aSL �7 ds -e =2 4 y„=1,32' DS — us �w>✓ IE C.4E, I£ 4- Q1,4 4 L �G t� C� b4eo� 2 2..16'i ft-1 319 5,19 5' (3Z.u`) RAINFALL PERFORMANCE STANDARD EVALUATION PROJECT: -�,o� ES S STANDARD FORM A COMPLETED BY: rn)r� DATE: -Z„ DEVELOPED ERODIBILITY SUBBA§IN ZONE Asb (ac) Lsb Ssb Lb Sb PS (ft) ($) (feet) (�) Rl 46�- o,z3 357 I.ea -lvs D S9S o .3� 3SS 0,6 F o.� G I �.IZ ssn i.a G3 �� I S4 qoz o,u MARCH 1991 8-14 DESIGN CRITERIA EFFECTIVENESS CALCULATIONS PROJECT: Lon DARD FORM B COMPLETED BY: fj�Im DATE: Z,I Erosion Control C-Factor P-Factor Method Value Value Comment �c,ds "Os. 101 I.o �c�ss Vo 1.0 Cvuvg1-�a) ,010 I - D o.� 1,,1c� er C ,�11Ly Sk►r. v5c. l cz 0 S MAJOR PS SUB AREA BASIN ($) BASIN (Ac) CALCULATIONS 10,- Li.S� siw�Vrs Z .31 sac . O'Tb kc, �cedetL �TC'e�ai A = t.7r, N.- MARCH 1991 8-15 DESIGN CRITERIA STEWART&ASSOCIATES 10 482 9 3DiRUM, FAX FORT gOLLINS, CO 80521 Consulting Engineers and Surveyors 1' am By:.mm Date: 1 _ Client: x(a' -r\p�,� ` , Sheet No. � of 1 Project: Subject: +�ern�•e�! Sr_�dtr� C �b Socks Cv -b Cko- 5 A-rck-w —tc"`es IrNIL.-—+r6-";er, L�akex- qukk; V, S\•c-uc� I (�) 4I00o`m I0C5a z3'�91 (a) �, I LA--- z � 8o (� , Vs 4e, C�) A-.3col,r� i , Lis O.iS ac-(-z sGs4gL q I Z .50 ") (-.-) �'- Lck� /Of Q ¢coou 46, S CQ �1S Lov 7S y GD tc= I X-Jilx- c *ZQ=�� 'T-&W C1,0771. So Gpm,"1�4\0A cm k X I .S Q C'ty ee"'v I,S g0-71.50 J13-�k0-7-Z5 No Text O mn � O F- N PRIVATE O H00 -� Z N DRIVE r �� 00 Z 0_ ROAD LES <�t= III N FI I I O III I 0 O F 00 12*0 1 Z N ADS (�0 Ch PRIVAI� Z DRIVE II 1 I 0- zEAD�'ll,r HEAD WALL 12P0 STEEL PIP 12.0 RCP 2/ �B c 020 If v 4.42 0.25 I G 2 E � 1 C ; \/ I 1.52 0.2E I / 1 SHALLOW LATER 11 / IRRIGTI AAL I 11 I I _.> ® ` I S EDGE OF rGRAVEL `D RCP FALCON ROAD NOTE: STORM WATER RUNOFF IS CURRENTLY NOT DETAINED ANID RELEASES INTO EXISTING ROADSIDE SWALES AND PLEASANT VALLEY & LAKE CANAL ai TRACT A NORTHEAST 1 /4 OF SECTION 28 TOWNSHIP 7 NORTH, RANGE 69 WEST LARIMER COUNTY, COLORADO GENERAL NOTES: 1, SITE CONTOURS ARE BASED ON NGVD 29 SURVEY DATUM 2. EXISTING CONTOURS ARE SHOWN AT ONE FOOT INTERVALS 3, SITE IS PRESENTLY USED AS FLOOD IRRIGATED PASTURE DRAINAGE LEGEND SCALE - 1 "=50' SURFACE FLOW DIRECTION so 0 50 Iqp (CONCENTRATED FLOW) SURFACE FLOW DIRECTION GRAPHIC SCALE - FEET (SHEET FLOW) A A=SUB-BASIN DESIGNATION B=AREA IN ACRES B C C=COMPOSITE RUNOFF COEFFICIENTS BENCHMARK C.= (2year event) City of Ft. Collins B.M. No. 6-02 C,m = (100year event) Elevation = 5113.7E D D=DESIGN POINT DESIGNATION 1/2 mile North of Horsetooth Rood on the East side of 3040 South Iraft Hill Road on the Northeast corner of a storm inlet. V SUMMARY RUNOFF TABLE I 8*0 STEEL PIPE EXISTING DRAINAGE CONDITIONS i BASIN DESIGN POINT CONTRIBUTING AREA (ACRES) 0(2),cfs 0(100),cfs A 1 _ 0.71 0.30 1.38 B _ _ 1.67 _ 0.51 2.28 C 1.52 0.48 2.16 D 4.42 1.20 5.43 E 1.03 0.43 1.98 F 0.34 0.19 0.B6 G 1 6 1 0.84 0.24 1 1.08 TOTAL 10.53 3.35 15.17 s = SHEET, FLOW, NO DEFINED CONCENTRATED POINT LEGEND: SUB -BASIN BOUNDARY ----- - - - -P SITE BOUNDY/PROPERTY LINE --- EXISTING MI OR CONTOUR EXISTING MA11OR CONTOUR �s^ CANAL CENRUNE CENTERUNE PF ROAD EDGE OF ORAVEL ROAD M z z ox F .J K FFn 7 0 U a: O W O 1 i=11111i1� 3 m � N v , m LLl � � a as 0 Qw�li U > oI O " �I (J� z o (J 0'5 n U a W W J Y W ��jjz i z "C1 o E5 U IIS W � ICY_ v o Z Q a _ z G m W c/0 w' _ �w Y CL Q jO CO - LL1 LLj F Z J O O S (n O w 0 W Z Z Z 0 0 Q z ~ W G -.ae x�rml wrz 6146 12/13/06 -- -- Senn NIYBffl 1 2 DRAINAGE SWALE WITH 2' CONCRE-E VALLEY PAN O 0 75% 12' CROSSPAN 13' CURB C11- Ell PROPOSED DRAINAGE PLAN DRAINAGE SWALE SCALE 150 WITH 2' CONCRETE VALLEY PAN O 0.4% w TC LOT 6� '7 SLOT 5' DRAINAGE SWALE \ 1,56 o:5s �, WITH 2' CONCRETE LONGWING DRIVE P� -.. VALLEY PAN O 0.4% f 1 I- 1 o. _ II 045 LOT 4 L07 8 ,3 LOT 13 J 056 1 '/ II A2 1 045 1 I I " LOT110 60 A A& 1 LOT 12 LOT 11 ( I Q I Oi 3 1 I '� r---- 1 LOT 2 I ( � � DETENTIO NA 1 POND t" Y n U LOT 7 s, 1 v ` L Alas - --�. POND DATA POND INVERT ELEV = 5102,87 VOLUME REQUIRED = 1.07 AC -FT VOLUME PROVIDED = 1,12 AC -FT RELEASE RATE = 3,35 CF5 100-YR WATER SURFACE ELEV = 5106.25 WATER QUALITY VOLUME REQUIRED = 0.19 AC. -FT WATER QUALITY VOLUME PROVIDED = 0.4,3 AC -FT (VO-UME A7 TOP OF WATER QUALITY PLATE) 1 I 1 V SCALE - 1"=50' 0 Vo 100 r GRAPHIC SCALE - FEET LEGEND SUB -BASIN BOUNDARY ..---------- SITE BOUNDARY/PROPERTY LINE -- - --- EXISTING,MINOR CONTOUR - EXISTING MAJOR CONTOUR CENTERLINE OF ROAD UTILITY EASEMENT -- -- -- PROPOSED CONTOUR 5110 DRAINAGE LEGEND �1 SURFACE FLOW DIRECTION (CONCENTRATED FLOW) SURFACE FLOW DIRECTION (SHEET FLOW) A A=SUB-BASIN DESIGNATION B=AREA IN ACRES B C, C=COMPOSITE RUNOFF COEFFICIENTS C. _ (2year event) Cmo= (100reor event) D=DESIGN POINT DESIGNATION `LRGENCI SPILLWAY REMOVE 72'0 STEEL PIPE PROPOSED MANHOLE EXISTING AREA INLET \ / TO BE REMOVED 1 1 INSTALL 5' TYPE R \ 1 8.70 1800 RCP cP�P TING POND OUTLET M REPLACE WITHEXIPROPOSED E 18 0 STORM RCP�� N 24'0 Rf-P OU TRIPLE TYPE R INLET 12' CROS.BPAN BASIN 02(ala) Qlft(C A7 0." 1.94 A2 1.70 7.81 B 1 32 6.05 C O55 2.45 0 0.22 1 01 E 0.29 1.26 F 0.21 0.93 G1 LOS 5.02 G2 0.74 3.37 G3 0.52 2.27 H 0.65 3.76 1 0.29 1.32 DESIGNPOINT QT(d) Qim(c ) 1 1.% 9.02 2 3.V 13.W 3 0.� 3.13 4 ie3 17.W 5 2.12 974 6 2.52 9.w 7 6.52 2516 =�- FALCON DRIVE - - EXISTING AREA m L1_J o o Q U > m 0 � �. S V / o iE < Q o U' Q w w Z o 9 C�d 1 I- Z w 0 U z w 'IG Z LLJ 0 .. E LL Y ( / N a = >v w 0 Q Z � Q w w J Q 0 O(n c� w w w (n Z Z O Q Q O Z ch 11 .a N.TEz 61 46 12/21/07 sHm wuecA 2 2