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Drainage Report , Drainage Study FOR CREEK MEADOWS SUBDIVISION Section 3, Phase Three College Station Brazos County, Texas August 18, 2014 ._ t%ti ,• * �► • . • e/ • it OPJA L +` Prepared For: Creek Meadow Partners, L.P. c/o Oldham Goodwin Group, LLC 2800 South Texas Avenue, Suite 401 Bryan, TX 77802 Prepared By: RME Consulting Engineers Texas Firm Registration No. F-4695 P.O. Box 9253 College Station, TX 77845 RME No. 260-0426 Drainage Study FOR CREEK MEADOWS SUBDIVISION Section 3, Phase Three College Station Brazos County, Texas August 18, 2014 ......• EOF 7---*71k1 i i j' i. 40601, `‘•%•.„.A tb 1‘,1 Prepared For: Creek Meadow Partners,L.P. c/o Oldham Goodwin Group,LLC 2800 South Texas Avenue, Suite 401 Bryan,TX 77802 Prepared By: RME Consulting Engineers Texas Firm Registration No.F-4695 P.O.Box 9253 College Station,TX 77845 RME No. 260-0426 Drainage Study CREEK MEADOWS SUBIDIVISION Section 3, Phase Two College Station Brazos County, Texas TABLE OF CONTENTS: PAGE 1.0 General Information 1 1.1 Scope of Report 1 1.2 Site and General Location 1 1.3 Description of Existing Conditions and Drainage Patterns 2 1.4 FEMA Information 3 2.0 Watersheds& Drainage Areas 3 2.1 Detention Facility Watershed 3 2.2 Sub-Drainage Basins for Storm Sewer Collection System 3 3.0 Hydrologic Modeling 4 3.1 Rational Formula and Methodology 4 3.2 Stormwater Runoff Quantities 5 4.0 Storm Drainage System 5 4.1 Street Drainage 5 4.2 Storm Drain Inlets 6 4.3 Storm Drain Conduits 7 5.0 Certification 9 260-0426 Drainage Report-S3P3.docx Page-i LIST OF TABLES: PAGE Section 4.0—Storm Drainage System Table#1: Street Drainage Summary 5 Table#2: Curb Inlet Summary 7 Table#3: Storm Drainage Summary 9 260-0426 Drainage Report-S3P3.docx Page-ii ATTACHMENTS: Section 1.0—General Information Preliminary Plat Final Plat Vicinity Map Section 2.0—Watersheds&Drainage Areas Storm System"A"—Drainage Area Map Section 4.0—Storm Drainage System Winstorm—Hydraulic Computations ST-01: Street&Drainage Plan/Profile 260-0426 Drainage Report-S3P3.docx Page-iii Drainage Study CREEK MEADOWS SUBIDIVISION Section 3, Phase Three College Station Brazos County, Texas 1.0 GENERAL INFORMATION 1.1 Scope of Report: This report addresses the existing conditions and proposed drainage improvements for the Creek Meadows Subdivision - Section 3, Phase Three. This development will consist of 21 single-family residential lots. This drainage study's scope also comments on the existing detention facilities, currently constructed and designed/reported, for this phase of development and is wholly contained in Section 1B of the original development of the Creek Meadows Subdivision. In addition, this drainage report outlines the internal storm drainage system improvements design and analysis for the subject development. The proposed development and drainage improvements are designed and analyzed in accordance with the criteria outlined in the "Unified Stormwater Design Guidelines" (USDG)manual of the City of College Station(CoCS). 1.2 Site and General Location: The master planned development, Creek Meadows subdivision, consists of 293.222 acres of land consisting of three tracts (20.179 acre tract, 176.043 acre tract, and a 96.00 acre tract). Section 3, Phase Three will consist of 4.766 acres, located within the southwestern corner of the 176.043 acre tract, and will consist of the platting of twenty-one (21) residential lots with the construction of their associated improvements of paving, drainage, and utilities. The proposed and future surrounding developments and phases are depicted on the Preliminary Plat which is provided in the "Attachment— Section 1.0" portion of this report. Also,the Final Plat of Creek Meadows— Section 3, Phase Three is provided in the same location of this report. The parent 176.043 acre tract is bordered by Greens Prairie Trail to the East, Royder Road to the South and Southwest, and Greens Prairie Road West to the West. Developments adjacent to the parent tract, all of which are rural residential, consist of Royder Ridge to the South, Woodlake to the East, and Wellborn Oaks to the Northeast. Access to the subdivision will be accomplished by Royder Road, Greens Prairie Trail and Greens Prairie Trail West. The subject development, Creek Meadows Subdivision — Section 3, Phase Three, is adjacent and immediately northwest of Section 3, Phase Two which is under construction at the time of this report. A Vicinity Map, for this project site, is provided and is located in the "Attachment — Section 1.0" portion of this manual. This map is being provided as an aid in locating the site. Drawings describing the work and its specific locations are contained in the 260-0426 Drainage Report-S3P3.docx Page-1 Creek Meadows—Section 3,Phase Three RME Consulting Engineers Drainage Study August 18,2014 Construction Drawings prepared by RME Consulting Engineers, College Station, Brazos County, TX. These Construction Drawings are included as part of this Drainage Report by reference. 1.3 Description of Existing Conditions and Drainage Patterns: The 176.043-acre tract, which contains the proposed development of Creek Meadows Subdivision — Section 3, Phase Two, is primarily an unimproved area with moderately well sloping (approximately 1.0%) undeveloped site with natural drainage systems that convey runoff to either an existing drainage storm sewer system, which is part of the Creek Meadows Subdivision, or Peach Creek South Tributary 20. Existing land-cover general consists of open grassy areas with some thick brush, weeds, and trees. Elevations range on the site from approximately 296' Mean Sea Level (MSL) to approximately 306' MSL. The Brazos County soil maps, as reported on the NRCS Web Soil Survey web- based program, indicates that the studied area is primarily comprised of Type C and D soils. These soils generally consist of clays or silty clay/sand mixtures with low absorption rates. Pre-development runoff, from the 176.043 parent tract, flowed through a series of existing stock ponds and then into a well-defined creek that develops along the southern property line of the subject parent tract. Peach Creek South Tributary 20 is well defined and pristine in nature downstream of these existing stock ponds. At current or post-development conditions, runoff is conveyed by means of overland flow or by systems of underground storm drainage that discharges runoff into Pond 1. Pond 1 is a retention/detention pond with a normal pool elevation of 308.00' and a maximum berm or ponding elevation of 312.50'. Runoff is then routed through Pond 1, via a trapezoidal shaped weir, and into Pond 2. Pond 2 is "dry" pond with a bottom elevation of 303.00' and a maximum berm or ponding elevation of 309.34'. Runoff routed through Pond 2 is then discharged through a double barrel box culvert and into Pond 3. Pond 3 is a retention/detention pond with a normal pool elevation of 302.00' and a maximum berm or ponding elevation of 306.64'. Runoff routed through Pond 3 is then discharged through a double barrel box culvert and into Pond 4. Pond 4 is"dry"pond with a bottom elevation of 295.50' and a maximum berm or ponding elevation of 301.00'. Runoff routed through Pond 4 is then discharged through a trapezoidal weir and into the headworks Peach Creek South Tributary 20. A more descriptive analysis and explanation of these tiered detention facility networks is provided in Section 6 of the original Drainage Study(prepared by RME on March 8, 2007). Section 3,Phase Three is both upstream and downstream of these four(4) detention pond system. The downstream portion is in the "undetained" area of the watershed. However, detention for new impervious cover, within this development, was accounted for in this original study and design. Therefore, no additional detention will be required for this phase. 260-0426 Drainage Report-S3P3.docx Page-2 Creek Meadows—Section 3,Phase Three RME Consulting Engineers Drainage Study August 18,2014 1.4 FEMA Information: The entire master planned Creek Meadow Subdivision does not lie within mapped 100- year floodplain as graphically depicted by the Federal Emergency Management Agency (FEMA) —Flood Insurance Rate Map (FIRM) Community/Panel number 480083 0325E, with an effective date of May 16, 2012. However, with the original Drainage Study for Creek Meadows — Section 1 A & 1B (dated March 8, 2007), RME performed a hydraulic analysis of Peach Creek South Tributary 20 between Royder Road and upstream to the called Pond 4 of Creek Meadows. The resulting proposed 100-year floodplain is illustrated in plan view on the Preliminary Plat and as stated before is contained in the "Attachment — Section 1.0" portion of the report. This floodplain model was updated to included the Greens Prairie Trail box culvert improvements, constructed with the new elementary school, and is reflected on the Final Plat of Creek Meadows — Section 3, Phase Two. As illustrated a small portion of Section 3, Phase Two does contain the resulting 100-year floodplain. 2.0 WATERSHEDS & DRAINAGE AREAS 2.1 Detention Facility Watershed: As previously discussed, the Creek Meadow Subdivision and subject development (Section 3, Phase Three) is located in a watershed of Peach Creek South Tributary 20. This Drainage Report will not include the hydrologic/hydraulic modeling of detention facilities and floodplain evaluation. Detailed analysis and reports of these detention facilities can be examined in the original Drainage Study (prepared by RME on March 8, 2007) for Section 1B. However, considerations for detention storage and development requirements were provided for with this development in the subdivision's detention facilities. 2.2 Sub-drainage Basins for Storm Sewer Collection System: For analysis of the internal storm drainage system, the Storm Sewer Drainage System "A" (as identified in the original study) was further broken into smaller sub-drainage areas so that individual curb inlets, grate inlets, and conveyance elements could properly be designed and analyzed. The Storm System"A"—Drainage Area Map, illustrates these sub-drainage areas, and is located in the "Attachment — Section 2.0" portion of this Drainage Study. The sub-drainage areas, per system, are briefly described below. Please note that when sub-drainage areas abutted or received runoff from future phases the hydrologic model reflected the worse-case scenario for that receiving node. Dependent upon location dictated whether existing drainage conditions were modeled or future development conditions were modeled. This is due to the fact that at future development conditions some receiving system's node areas will be significantly decreased. 260-0426 Drainage Report-S3P3.docx Page-3 Creek Meadows—Section 3,Phase Three RME Consulting Engineers Drainage Study August 18,2014 • System A — Drainage system for portion of Sunny Meadow Brook Court located in Section 1B, Phase Four and the west half of Shady Brook Lane located in the subject phase; 3.0 HYDROLOGIC MODELING 3.1 Rational Formula and Methodology: The Rational Method (Q=CIA) is one of the more frequently used methods to determine the peak runoff from a watershed and is typically reliable for small watersheds (< 50 acres). The Rational Method generates hydrologic data based on drainage area geometrics, surface conditions, and rainfall intensities. The Rational Method will be employed to determine these sizes of watershed's runoff values, for the sub-drainage areas for the internal storm drain systems, and it is explained further as: Q=CIA where, Q=peak runoff rate (cubic feet per second); C = runoff coefficient — This represents the average runoff characteristics of the land cover within the drainage area and is a dimensionless coefficient. Runoff coefficients are interpolated from either Table C-2 or C-3 of the USDG; I=average rainfall intensity(in/hr); A=area of land that contributes stormwater runoff to the area of study (acres); RUNOFF COEFFICIENT(C): The runoff coefficient(C)for various sub-drainage basins was estimated from the USDG, Table C-2 and C-3 by comparison of runoff surface types to percentage of land coverage and total drainage area. Calculations for these weighted runoff coefficients are included in the"Attachment—Section 4" section of this Drainage Study. TIME OF CONCENTRATION "Tc": The Time-of-Concentration (Tc) for each sub-drainage basin is used to determine the intensity of the rainfall event for the corresponding drainage basin. Time-of- Concentration is defined as the time required for the surface runoff to flow from the most remote point in a watershed to the point of analysis. The Tc is the summation of the flow time for shallow overland flow and/or concentrated flow to the lower reach of the watershed. Overland sheet flow is a method developed by Overton and Meadows and is typically used for flow distances of 300 feet or less. Concentrated flows are estimated by velocities determined by use of the Manning's Equation. The minimum T, used for any drainage area will 10.0 minutes. RAINFALL INTENSITY(I): Rainfall intensities (I) are the average rate of rainfall in inches per hour for a given rainfall event. The duration of "I" is assumed to occur at the computed Time-of- Concentration for each respective drainage basin. Rainfall intensities can be determined 260-0426 Drainage Report-S3P3.docx Page-4 Creek Meadows—Section 3,Phase Three RME Consulting Engineers Drainage Study August 18,2014 by use of intensity-duration-frequency(IDF) curves or from intensity equations which are provided in the TxDOT Hydraulic Manual. 3.2 Stormwater Runoff Quantities: Stormwater runoff quantities were calculated, using the Rational Method, with the assistance of the Hydrologic/Hydraulic stormwater modeling program WINSTORM, produced by TxDOT. These runoff conditions are at post-development conditions and their supporting data are contained the"Attachment—Section 4"of this Drainage Report. 4.0 STORM DRAINAGE SYSTEM The "system criteria" listed below in the follow sub-sections are only the main highlights of the CoCS — USDG. The proposed development and drainage improvements are designed and analyzed in full accordance with the criteria outlined in this manual. 4.1 Street Drainage SYSTEM CRITERIA: 1. The maximum velocity of street flow shall not exceed 10 fps. At "T" street intersection the flow velocity will be checked on the stem of the "T". The minimum velocity shall be maintained by keeping a gutter slope of 0.60%or greater; 2. The depth of flow shall be limited to the top of the curb for the design flow (10-year rainfall event) and shall be contained within the right-of-way during the 100-year rainfall event: a. Local Streets — The design storm in local streets shall be limited to the top of crown or the top of curb,whichever is less; b. Collector Streets — Design storm flow in collector streets shall be limited so that one 12-foot wide area at the center of the street will remain clear of water; 3. Curb inlets shall be placed in a manner to ensure that the design storm flows are intercepted along street legs in advance of the curb returns. For intersection types of Collector to Local the curb inlets shall be placed along the local legs. For intersection types of Local to Local it is preferred that the curb inlets be located along two legs. METHODOLGY& CONCLUSIONS: The hydraulic analysis, for street drainage with straight crowns, and corresponding results were determined by using the following equation for triangular channels. Corresponding flows for the studied locations were extracted from the WINSTORM hydraulic program, for stormwater modeling. This TxDOT program's typical use is for modeling gravity stormwater systems. The Winstorm data is summarized, for each system, under the Winstorm—Hydraulic Computations (reference "Attachment— Section 4.0"portion of the report). Flow Depth,Y= {Qn/ [(0.56z*S15)1}3B where, Y=depth of flow(ft); 260-0426 Drainage Report-S3P3.docx Page-5 Creek Meadows—Section 3,Phase Three RME Consulting Engineers Drainage Study August 18,2014 Q= gutter discharge(cubic feet per second); z=reciprocal of the crown slope(ft/ft); S =street or gutter slope (ft/ft); n=Manning's roughness coefficient(typically 0.012); Flow Velocity,V= [(1.49--n) * (R2/3 * S"2)] where, V=velocity of flow(fps); R=hydraulic radius(cross-sectional area/wetted perimeter); S =street or gutter slope (ft/ft); n=Manning's roughness coefficient(typically 0.012); Street drainage depths, for the both the design storm and 100-year rainfall event, are summarized below in Table#1 —"Street Drainage Summary". TABLE#1 STREET DRAINAGE SUMMARY 10-YR 100-YR 10-YR 100-YR Gutter Flow Flow 10-YR 100-YR Runoff Q Runoff Q Slope Depth Depth Velocity Velocity Location (cfs) (cfs) (ft/II) (ft) (ft) (fps) (fps) Sunny Meadow Brook Ct.-CI"Al" 4.343 6.664 0.0068 0.28 0.33 2.12 2.36 Sunny Meadow Brook Ct.-CI"A2" 7.984 10.763 0.0103 0.33 0.37 2.89 3.11 Sunny Meadow Brook Ct.-CI"A3" 7.638 10.161 0.0103 0.32 0.36 2.86 3.07 Street Drainage Notes: 1. Design calculations are with a n=0.018 and 233.3(cross-slope of 3.00%); 2. Runoff rates illustrated are from the Winstorm program. These Q's are the total runoff values being conveyed in the gutter immediately upstream of the identified inlet. For curb inlets at grade, the total runoff is input in lieu of that inlet's intercept capacity; 3. The maximum allowable depth, during the design storm, for all streets it is 0.42'. The maximum allowable depth,during the 100-year event for all right-of-ways,is 0.54'; 4. Sunny Meadow Brook Ct."Al"will experience a greater flow depth than either side of Shady Brook Lane. Therefore, Shady Brook Lane is not included in this analysis. Flow illustrated here also includes pass thru flow from "A2" and "A3" but reduced by 50% to simulate flow from each direction of the cul-de-sac; 4.2 Storm Drain Inlets SYSTEM CRITERIA: 1. All curb inlets within this project are specified as recessed curb inlets with gutter depressions. Curb inlets that are located on streets with less than a 1% longitudinal slope shall be analyzed as curb inlets at sumps; 2. At any developments scenario and analyzed rainfall event, up to the 100-year frequency,the ponding depth at the inlet shall not exceed 24"; METHODOLGY& CONCLUSIONS: The hydraulic analysis, for curb inlet sizing, and corresponding results were determined by using the following equation from the USDG, Table C-8 of Appendix C. Corresponding flows for the studied locations were extracted from the WINSTORM hydraulic program, for stormwater modeling. This TxDOT program's typical use is for modeling gravity stormwater systems. The Winstorm data is summarized, for each 260-0426 Drainage Report-S3P3.docx Page-6 Creek Meadows—Section 3,Phase Three RME Consulting Engineers Drainage Study August 18,2014 system, under the Winstorm—Hydraulic Computations (reference "Attachment— Section 4.0"portion of the report). Required Curb Length (on grade),L =Kc Q°'42S°3(1 T(nSe))°'6 where, Se=Sx+(Eoa=W) L=calculated curb length requirement(ft); Se= Substitution for Sx which is the cross slope of the road(ft/ft); Kc=0.6 (coefficient); S = street or gutter slope (ft/ft); a=gutter depression depth(ft); W=width of gutter depression(ft); E0=ratio of frontal flow to total gutter flow(estimated at 0.50); Required Curb Length (at sag),L=Q/(3.0*y13)where, L=calculated curb length requirement(ft); Q=gutter discharge (cubic feet per second); y=total depth of water or head on the inlet(ft); Curb inlet sizing, for the both the design storm and 100-year rainfall event, are summarized below in Table#2—"Curb Inlet Summary". TABLE#2 CURB INLET SUMMARY 10-YR 100-YR 10-YR 100-YR Gutter Required Required Provided Curb Inlet Runoff Q Runoff Q Slope Length Length Length Location-Curb Inlet I.D. Type (cfs) (cfs) (fi/ft) (ft) (ft) (ft) Sunny Meadow Brook Ct."Al" Sag 8.686 13.595 0.0068 9.10 14.24 15 Wild Creek Ct.-CI"C5" Grade 7.984 10.763 0.0103 15.03 17.04 10 Wild Creek Ct.-CI"C6" Grade 7.538 10.161 0.0103 14.67 16.64 10 Curb Inlet Notes: 1. Design calculations are with a standard gutter depression depth(a)of 0.33' and standard depression width(W)of 2'; 2. Design calculations are with a n=0.018 and a standard cross-sectional slope of 3.0%(0.03 ft/ft); 3. Curb inlets analyzed at sags will utilize the depth(y)of 6"unless otherwise noted; 4. Curb inlets at grade were allowed to be undersized so long as the downstream gutter section and ultimate receiving sag inlet could accommodate conveyed flows; 5. Inlets at sags where reduced by 10%(opening)to account for clogging; 4.3 Storm Drain Conduits SYSTEM CRITERIA: 1. Storm drainage systems are designed to convey the design storm and analyzed during the 100-year rainfall event. An gravity over-flow route, contained within the right-of- way or public drainage easement, has been provided so that conduits that are unable to convey the 100-year storm can "spill" over into these over-flow systems so that situations that are hazardous to life, property, or public infrastructure is prevented; 260-0426 Drainage Report-S3P3.docx Page-7 Creek Meadows—Section 3,Phase Three RME Consulting Engineers Drainage Study August 18,2014 2. For the design storm the minimum flow velocity in a conveyance element shall not be less than 2.5 fps and not greater than 15.0 fps; 3. Roughness coefficients for storm sewer pipes were assigned at 0.012 for smooth-lined High Density Poly-Ethylene (HDPE)pipe and 0.013 for RCP; 4. Junction boxes were provided at all changes in conduit size and grade or alignment changes. Where junction box spacing exceeded 300 feet for 54" diameter pipe, or smaller, and 500' for pipes exceeding 54" in diameter, additional manhole holes were provided to maintain the desired spacing; 5. Storm sewer conduits with a diameter of 18"through 24"were hydraulically analyzed with a 25% reduction in cross-sectional area to compensate for potential partial blockage. Therefore 18" sized pipes were input as 1.30' diameter pipe and 24" sized pipes were inputted as a 1.73' diameter pipe; 6. Conveyance elements were sized so that the design storm's hydraulic grade line would equal to or less than 12"below the respective curb inlet curb elevation; 7. Free-open area of all grate inlets were reduced by 25%to compensate for cloggage; TAILWATER CONSIDERATIONS: Tailwater, for this drainage system, was set to equal that of the downstream drainage element. In this case, the corresponding Pond 4 pool elevation (designed & analyzed rainfall events). Therefore the design storm, 10-year event, had a TW=299.88', and the analyzed storm, 100-year event,had a TW=300.74'. METHODOLGY&CONCLUSIONS: The hydraulic analysis, for storm drain conduits, and corresponding results were determined by using the WINSTORM hydraulic program,for stormwater modeling. This TxDOT program's typical use is for modeling gravity stormwater systems. The Winstorm data is summarized, for each system, under the Winstorm — Hydraulic Computations (reference "Attachment — Section 4.0" portion of the report). Also, for graphical illustration purposes the hydraulic grade line (HGL), for the 10-year and 100- year, are identified on ST-01 Street & Drainage Plan/Profile of the construction drawings (see"Attachment—Section 4.0"portion of the report). Storm drain conveyance elements and system, for the design storm (10-year rainfall event) and analyzed storm(100-year rainfall event), are summarized below in Table#3 — "Storm Drainage Summary". As illustrated the HGL of this system is contained within the storm sewer pipe completely during both studied rainfall events (with exception noted on Comment#3 —Table#3). 260-0426 Drainage Report-S3P3.docx Page-8 Creek Meadows-Section 3,Phase Three RME Consulting Engineers Drainage Study August 18,2014 TABLE#3 STORM DRAINAGE SUMMARY Pipe Size US Top of US Node DS Node Diameter Velocity Capacity Runoff Q US HGL Curb Diff ID ID (in) (fps) (cfs) (cfs) (ft) Elev.(ft) (ft) SYSTEM"A"-10 YR RAINFALL A-1 OUT1 30 8.09 38.61 21.43 300.18 303.80 -3.62 A-2 A-1 24 6.89 19.61 15.46 302.27 305.96 -3.69 A-3 A-2 24 3.67 19.40 7.54 302.31 305.96 -3.65 SYSTEM"A"- 100 YR RAINFALL A-1 OUT1 30 6.60 38.61 28.91 300.85 303.80 -2.95 A-2 A-1 24 6.97 19.61 20.85 302.74 305.96 -3.22 A-3 A-2 24 3.55 19.40 10.16 302.75 305.96 -3.21 Storm Drainage System Notes: 1. All storm sewer system outfalls are specified with velocity dissipaters at the headwall; 5.0 CERTIFICATION "This report for the drainage design of Creek Meadows-Section 3, Phase Three was prepared by me (or under my supervision) in accordance with provisions of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits required by any and all state and federal regulatory agencies for the proposed drainage improvements have been issued." = 1 f::; •,, .,* % :ON A. fE1CA. ...AP� #4.°1 i; -. *'', . PI f-1:1---:\..... tll "sr 3 �_ 1 Rabon Metcalf, P.E. State of Texas P.E.No. 88583 Texas Firm Registration No. F-4695 260-0426 Drainage Report-S3P3.docx Page-9 Section 1 .0 GENERAL INFORMATION Section 4.0 STORM DRAINAGE SYSTEM stmOutput.txt Version 3.05, Jan. 25, 2002 WinStorm (STORM DRAIN DESIGN) Run @ 8/18/2014 2: 35:47 PM PROJECT NAME : 260 JOB NUMBER : 0426 PROJECT DESCRIPTION : Creek Meadows-S3Ph3-System A DESIGN FREQUENCY 10 Years ANALYSYS FREQUENCY : 100 Years MEASUREMENT UNITS: ENGLISH OUTPUT FOR DESIGN FREQUENCY of: 10 Years Runoff Computation for Design Frequency. ID C Value Area Tc Tc Used Intensity Supply Q Total Q (acre) (min) (min) (in/hr) (cfs) (cfs) A-1 0.753 0. 99 10.00 10.00 8 . 63 0.000 6. 440 0.96 0.33 Pavement 0.65 0. 66 Single family 0.000 7 . 984 A-2 0.728 1.27 10. 00 10.00 8.63 0. 96 0.32 Pavement 0. 65 0. 95 Single family 0.000 7 .538 -3 0.728 1.20 10.00 10.00 8 . 63 0.96 0.30 Pavement 0. 65 0.90 Single family On Grade Inlet Configuration Data Inlet Inlet Inlet Slopes Gutter Grate Pond Width Critic ID Type Length Long Trans n Depr. Width Type Allowed Elev. (ft) (%) (%) (ft) (ft) (ft) (ft) A-2 Curb Curb 10. 00 1. 03 3.00 0.014 0.33 n/a n/a 12.00 305. 96 A-3 On Grade Inlets Conmputation Data. Inlet Inlet Total Q Intercept Q Bypass To Inlet Required Actual Ponded ID Type Capacity Allow Actual ID Length Length Width (cfs) (cfs) (cfs) (cfs) (ft) (ft) (ft) A-2 Curb 7 . 98 6.51 1.220 A-1 15.44 10.00 11.53 A-3 Curb 7 . 533 1 5.000 1.027 A-1 14 . 93 10.00 11.30 Page 1 stmOutput.txt ``+ sag Inlets Configuration Data. Inlet Inlet Length/ Grate Left-Slope Right-Slope GutterW Al .Depthd h Criti ID Type Perim. Area Long Trans Long Trans n Dep (ft) (sf) (%) (%) (%) (%) (ft) (ft) (ft) A-1 Curb 15.00 n/a 0. 68 3.00 0.79 3.00 0.014 1.50 0.50 303.80 Sag Inlets Computation Data. Inlet Inlet Length Grate Total Q Inlet t Totald Ponded WLeft idth Ca ID Type Perim Area Capacity ht (ft) (ft) (sf) (cfs) (cfs) (ft) (ft) (ft) A-1 Curb 15.00 n/a n/a 8 .686 14 .393 0.357 9. 93 9. 63 Cumulative Junction Discharge Computations Node Node Weighted Cumulat. Cumulat. Intens. User Additional l Total I.D. Type C-Value Dr.Area Tc Supply y Q Q) (noncfs) (cfs) (acres) (min) (in/hr) A-1 Curb 0.735 3. 46 10. 61 8 . 42 0.000 0.00 21.427 0.00 21.4 -2 Curb 0.728 2.47 10. 10 8. 60 0.000 . 560 60 ` 0.00 5i-3 Curb 0.728 1.20 10.00 8 . 63 0.000 0.00 27 .538 OUT1 Outlt 0.735 3.46 10. 61 8 .42 0.000 Conveyance Configuration Data Run# Node I.D. Flowline Elev. US DS US DS Shape # Span Rise Length Slope n_value (ft) (ft) (ft) (ft) (ft) (%) 1 A-1 OUT1 298 .85 298. 65 Circ 1 0.00 2.50 26. 50 0.75 0. 012 2 A-2 A-1 300. 93 299.35 Circ 1 0.00 2. 00 210.32 0.75 0.013 3 A-3 A-2 301.28 301.03 Circ 1 0.00 2.00 34 .00 0.74 0.013 Conveyance Hydraulic Computations. Tailwater = 299.880 (ft) Junc Hydraulic Gradeline Depth Velocity Run# US Elev DS Elev F{ ;lope (f )• Actual Actual 4Cap Loss (ft) (ft) % t (f/s) (f/s) (cfs) (cfs) (ft) Niftw Page 2 stmOutput.txt 1* 300.18 299. 98 0.232 1.33 1.33 8.09 8.09 21. 43 38 . 61 0.000 4044%* 302.27 300. 69 0.467 0:8� 1.24 5.77.34 3. 67 6. 89 15.46 19. 61 0.000 7 . 54 19.40 0.000 `iripy* 302.31 302.27 0. OUTPUT FOR ANALYSYS FREQUENCY of: 100 Years Runoff Computation for Analysis Frequency. ID C Value Area Tc Tc Used Intensity Supply Q Total Q (acre) (min) (min) (in/hr) (cfs) (cfs) A-1 0.753 0. 99 10.00 10.00 11. 64 0.000 8. 680 0. 96 0.33 Pavement 0. 65 0. 66 Single family 11. 64 0.000 10.763 A-2 0.728 1.27 10.00 10.00 0. 96 0.32 Pavement 0.65 0. 95 Single family A-3 0.728 1.20 10.00 10.00 11.64 0.000 10. 161 0. 96 0.30 Pavement 0. 65 0. 90 Single family ClOn Grade Inlet Configuration Data Inlet Inlet Inlet Slopes Gutter Grate Pond Width Critic ID Type Length Long Trans n Depr. Width Type Allowed Elev. (ft) (%) (%) (ft) (ft) (ft) (ft) A-2 Curb 10.00 1.03 3.00 0.014 0.33 n/a n/a 12.00 305. 9612.00 305. 96 A-3 Curb 10.00 1.03 3.00 0.014 0.33 n/a n/a On Grade Inlets Conmputation Data. Inlet Inlet Total Q Intercept Q Bypass To Inlet Required Actual Ponded ID Type Capacity Allow Actual ID Length Length Width (cfs) (cfs) (cfs) (cfs) (ft) (ft) (ft) A-2 Curb 10. 8 .143 18 . 39 12. 90 A-3 Curb 10. 1617 .866 5.000 2.295 A-1 17 .78 10.00 12. 63 Sag Inlets Configuration Data. Inlet Inlet Length/ Grate Left-Slope Right-Slope Gutter Depth Critic C Page 3 stmOutput.txt ID Type Perim. Area Long Trans Long Trans n DeprW Allowed Elev. (ft) (sf) (%) (%) (%) (%) (ft) (ft) (ft) A-1 Curb 15.00 n/a 0. 68 3.00 0.79 3.00 0.014 1. 50 0.50 303.80 Sag Inlets Computation Data. Inlet Total Ponded Width Inlet Inlet Length Grate Total Q Capacity Head Left Right ID Type Perim Area P Y (ft) (ft) (sf) (cfs) (cfs) (ft) (ft) (ft) A-1 Curb 15.00 n/a n/a 13.595 14.393 0. 481 11.73 11.40 Cumulative Junction Discharge Computations Node Node Weighted Cumulat. Cumulat. Intens. USerQ Additional l Dotal Supply I.D. Type C-Value Dr.Area Tc (cfs) (cfs) ch. (acres) (min) (in' /hr) cfs) A-1 Curb 0.735 3. 46 10.59 11. 37 0. 000 0. 00 28. 910 A-2 Curb 0.728 2.47 10.09 11. 60 0.000 0.00 28.910 0.00 20.847 A-3 Curb 0.728 1.20 10.00 11. 64 0.000 0.00 28 . 910 61 OUT1 Outlt 0.735 3. 46 10.59 11.37 0.000 Conveyance Configuration Data Run# Node I.D. Flowline Elev. Span Rise Length Slope n_value (ft) (ft) US DS US DS Shape # t)t) (ft) (ft) (%) 1 A-1 OUT1 298 .85 298.65 Circ 1 0.00 2.50 26.50 0.75 0. 012 2 A-2 A-1 300. 93 299.35 Circ 1 0.00 2.00 210.32 0.75 0. 013 3 A-3 A-2 301.28 301.03 Circ 1 0. 00 2.00 34 . 00 0.74 0.013 Conveyance Hydraulic Computations. Tailwater = 300.740 (ft) Junc Hydraulic Gradeline Depth Velocity Run# US Elev DS Elev Fr.Slope Unif. Actual Unif. Actual Q Cap Loss (ft) (ft) (%) (ft) (ft) (f/s) (f/s) (cfs) (cfs) (ft) 1* 300.85 300.74 0.423 1. 62 2.09 8.58 6. 60 28.91 38. 61 0.000 2 302.74300. 990202 1.03 1.49 1.81 71 6. 97 6. 97 20.85 19. 61 0.000 71 6.22 3. 55 10. 16 19.40 0.000 3* 302.755 302.74 . END Page 4 stmOutput.txt * Super critical flow. NORMAL TERMINATION OF WINSTORM. Warning Messages for current project: Runoff Frequency of: 10 Years Capacity of grade inlet exceeded at inlet Id= A-2 Capacity of grade inlet exceeded at inlet Id= A-3 Tailwater set to uniform depth elevation = 299. 98 (ft) Runoff Frequency of: 100 Years Capacity of grade inlet exceeded at inlet Id= A-2 Computed ponded width exceeds allowable width at inlet Id= A-2 Capacity of grade inlet exceeded at inlet Id= A-3 Computed ponded width exceeds allowable width at inlet Id= A-3 Run# 2 Insufficient capacity. Page 5