FINAL DRAINAGE REPORT FOR TAMLIN ROAD RV STORAGE …€¦ · FINAL DRAINAGE REPORT FOR TAMLIN ROAD RV STORAGE Page i FINAL DRAINAGE REPORT FOR TAMLIN ROAD RV STORAGE Prepared For:

FINAL DRAINAGE REPORT FORTAMLIN ROAD RV STORAGE

Page i

FINAL DRAINAGE REPORTFOR

TAMLIN ROAD RV STORAGE

Prepared For:

C&M Properties, LLC12748 Barossa Valley Road

Colorado Springs, CO 80921

June 13, 2019Project No. 25134.01

Prepared By:JR Engineering, LLC

5475 Tech Center Drive, Suite 235Colorado Springs, CO 80919

719-593-2593

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Add PCD File No. PPR1945

ENGINEER’S STATEMENT:The attached drainage plan and report were prepared under my direction and supervision and are correctto the best of my knowledge and belief. Said drainage report has been prepared according to the criteriaestablished by El Paso County for drainage reports and said report is in conformity with the master planof the drainage basin. I accept responsibility for any liability caused by any negligent acts, errors, oromissions on my part in preparing this report.

Mike Bramlett, Colorado P.E. # 32314 DateFor and On Behalf of JR Engineering, LLC

DEVELOPER'S STATEMENT:I, the developer, have read and will comply with all of the requirements specified in this drainage reportand plan.

Business Name: ROI Property Group, LLC

By:

Title:Address: 2495 Rigdon Street

Napa, CA 94558

EL PASO COUNTYFiled in accordance with the requirements of the El Paso County Land Development Code, DrainageCriteria Manual, Volumes 1 and 2 and Engineering Criteria Manual, as amended.

Jennifer Irvine, P.E. DateCounty Engineer/ ECM Administrator

Conditions:

Table of ContentsPurpose ................................................................................................................................................................ 4General Site Description ................................................................................................................................... 4

Location ........................................................................................................................................................... 4Description of Property ................................................................................................................................. 4

Existing Drainage Conditions .......................................................................................................................... 5Major Basin Descriptions .............................................................................................................................. 5Existing Sub-basin Drainage ........................................................................................................................ 5

Proposed Drainage Conditions ......................................................................................................................... 5Proposed Sub-basin Drainage ....................................................................................................................... 5

Drainage Design Criteria .................................................................................................................................. 6Development Criteria Reference .................................................................................................................. 7Hydrologic Criteria ........................................................................................................................................ 7Hydraulic Criteria ........................................................................................................................................... 7

Drainage Facility Design .................................................................................................................................. 7Four Step Process to Minimize Adverse Impacts of Urbanization ......................................................... 7Water Quality .................................................................................................................................................. 8Erosion Control Plan ...................................................................................................................................... 9Operation & Maintenance ............................................................................................................................. 9Floodplain Statement ..................................................................................................................................... 9Drainage and Bridge Fees ............................................................................................................................. 9Construction Cost Opinion..........................................................................................................................10

Summary ........................................................................................................................................................... 10References ......................................................................................................................................................... 11

APPENDIXAppendix A – Vicinity Map, Soil Descriptions, FEMA Floodplain MapAppendix B – Reference MaterialAppendix C – Hydrologic CalculationsAppendix D – Hydraulic CalculationsAppendix E – Drainage Maps

FINAL DRAINAGE REPORT FORTAMLIN ROAD RV STORAGE

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PURPOSE

This document is the Final Drainage report for Tamlin Road RV Storage. The purpose of this reportis to:

1. Identify on-site and off-site drainage patterns.

2. Recommend storm water facilities to collect and convey storm runoff from the proposeddevelopment to appropriate discharge and/or detention locations.

3. Recommend water quality and detention facilities to control discharge release rates to belowhistoric.

4. Demonstrate compliance with surrounding major drainage basin planning studies, masterdevelopment drainage plans and flood insurance studies.

GENERAL SITE DESCRIPTION

LOCATIONTamlin Road Storage Yard, known as ‘the site’ from herein, is currently vacant land located in aportion of Section 20, Township 13 South, Range 65 West of the Sixth Principal Meridian inunincorporated El Paso County, Colorado. The site is located northeast of the Tamlin Road andMarksheffel Road intersection. The site is bound by Tamlin Road to the west and north, vacant landowned by Norwood to the east and south. Stetson Hills Filing No. 3 and 4 is located adjacent to thesite on the west side of Marksheffel Road. A vicinity map has been presented in Appendix A.

Sand Creek East Fork tributary is located approximately ¼ mile east of the site. The ultimate outfallof this drainageway is Fountain Creek. However, there are no existing stormwater facilities locatedon site.

DESCRIPTION OF PROPERTYThe site is approximately 16.5 acres and is covered with sparse trees and native vegetation. There areno existing structures on the site. An existing dirt road proceeds southeast from Tamlin Road throughthe site to service an existing water tank, located south of the site. There is a ridge that divides thedrainage patterns on the site. Roughly 6.5 acres drains southwest with slopes between 3-10% whilethe remaining 10 acres drains northeast with slopes up to 8%. In the developed condition, the site willbe asphalt drive aisles, parking stalls and a small kiosk.

The site is comprised solely of Truckton sandy loam, which is classified as a Type A soil by theNRCS. Group A soils exhibit a high infiltration rate when thoroughly wet and consist chiefly ofdeep, well drained to excessively drained gravelly sands. These soils have a high rate of watertransmission. A NRCS soil survey map is presented in Appendix A.

There are no known irrigation facilities located on the project site. An existing water line (sizeunknown) runs north-south through the site in a 30’ utility easement. Additionally, a gas main (sizeunknown) runs parallel to the water main in a 50’ wide easement. Both existing utilities will remainand existing cover over the utilities will be maintained.

EXISTING DRAINAGE CONDITIONS

MAJOR BASIN DESCRIPTIONSThe site lies within the West Tributary Sand Creek regional sub basin within the Sand Creek MajorDrainage Basin. The “Sand Creek Drainage Basin Planning Study” prepared by Kiowa Engineeringrevised in March 1996, evaluated the Sand Creek Major Drainage Basin, the existing facilitiestherein and provided recommendations for future development. A map of the Sand Creek regionalsub basins is presented in Appendix B.

The Sand Creek Basin covers approximately 54 square miles in unincorporated El Paso County andColorado Springs, CO. The undeveloped portions of the basin are typified by rolling range land withfair vegetative cover associated with semi-arid climates. The headwaters of the basin are in TheBlack Forest and generally topography trends south to southwesterly towards its ultimate outfall intoFountain Creek. Per the Sand Creek DBPS, the Sand Creek East Fork Subtributary runs outside thewestern boundary of the site. This drainageway begins at the confluence with the mainstem of EastFork Sand Creek and runs north to Barnes Road.

Based on the FEMA FIRM Map number 08041C0543G and 08041C0545G, the site does not fallwithin a FEMA defined floodplain and is classified as Zone X, which are areas determined to beoutside the 0.2% annual chance floodplain. FIRM maps of the site and surrounding areas have beenpresented in Appendix A.

EXISTING SUB-BASIN DRAINAGEExisting drainage patterns are split on the site by a ridge running north-south. The eastern portion ofthe site drains across undeveloped land to Sand Creek East Fork Subtributary. The western portion ofthe site drains across Tamlin Road and Marksheffel road into Eastview Estates Filing No. 3 stormsewer.

PROPOSED DRAINAGE CONDITIONS

PROPOSED SUB-BASIN DRAINAGEIn general, runoff generated from the site will be collected and conveyed to one of two full spectrumwater quality and detention ponds, Pond A and Pond B, located on site. It should be noted that allproposed parking and drive aisles will be constructed of gravel. However, there is a possibility of the

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Provide an existing drainage plan showing appropriate basins and design points(Q) of the historic drainage flow patterns.

owner paving the drive aisles and parking stalls with asphalt in the future. Therefore, all calculations(hydrologic and hydraulic) have been performed per the future asphalt condition. The proposed basindelineation is as follows:

Basin A1 consists of approximately 6.04 acres of gravel drives, parking stalls and landscaped areas.Runoff from these areas will sheet flow east towards Water Quality Pond A.

Basin A2 consists of approximately 0.80 acres of gravel drives, parking stalls and landscaped areas.Runoff from this basin is collected in a grass-lined swale and conveyed to Water Quality Pond A.The cross sectional analysis of the drainage swale is presented in Appendix D.


Basin A4 consists of approximately 1.48 aces of gravel drives, parking stalls, landscaped areas andundeveloped land. Runoff from this basin will follow historic drainage patterns and sheet floweasterly off site and will not be detained in Water Quality Pond A. The portion of this basin that isdeveloped (0.09 acres) will not significantly increase the runoff from this basin in its undevelopedcondition.

Basin A5 consists of approximately 0.59 acres of landscape area and undeveloped land. Runoff fromthis basin will follow historic patterns and sheet flow easterly offsite and will not be detained inWater Quality Pond A.

Basin B1 consists of approximately 4.30 acres of gravel drives, parking stalls, and landscaped areas.Runoff from this basin is collected in a gravel pan located along the basin’s western border. Theasphalt pan will discharge into a grass-lined swale that conveys the runoff to Water Quality Pond B.The cross sectional analysis of the drainage swale is presented in Appendix D.

Basin B2 consists of approximately 1.31 acres of gravel drives, parking stalls and landscaped areas.Runoff from this basin sheet flows into Water Quality Pond B.

Basin B3 consists of approximately 0.90 acres of landscaped areas and undeveloped land. Runofffrom this basin will follow historic drainage patterns and sheet flow westerly to Tamlin Road. Runofffrom this basin will not be detained in Water Quality Pond B.

Any offsite flows entering the site will bypass the site and not be captured in the water quality anddetention ponds. However, little to no off-site runoff is anticipated to enter the site. Drainage DesignCriteria

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Please indicate the ponds as Full Spectrum detention ponds.

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Water Quality

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Water Quality Pond

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which is it? gravel or asphalt?

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asphalt

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gravel

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Please revise this paragraph regarding the offsite flows entering the site. It appears that you are stating that offsite flow will enter the site but bypass the ponds yet the last sentence indicates that offsite flow will not enter the site. If offsite flow is entering the site from where is this flow coming from and how will it bypass the ponds.

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Drainage Design Criteria

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Per ECM I.7.1.C.1 up to 20%, not to exceed 1 acre of the applicable development site may be omitted from water quality. The cumulative land disturbance proposed in basins A4, A5, and B3 will exceed 1 acre. Please revise your design accordingly to comply with County criteria.

DEVELOPMENT CRITERIA REFERENCEStorm Drainage Analysis and Design Criteria for this project were implemented from the El PasoCounty “Drainage Criteria Manual” (DCM) and the “Urban Storm Drainage Criteria Manual” byUrban Drainage and Flood Control District (USDCM).

HYDROLOGIC CRITERIAAll hydrologic data was obtained from the “El Paso County Drainage Criteria Manual" Volumes 1and 2, and the “Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual”Volumes 1, 2, and 3. Onsite drainage improvements were designed based on the 5 year (minor) stormevent and the 100-year (major) storm event. Runoff was calculated using the Rational Method, andrainfall intensities for the 5-year and the 100-year storm return frequencies were obtained from Table6-2 of the Colorado Springs Criteria. One hour point rainfall data for the storm events is identified inthe chart below. Runoff coefficients were determined based on proposed land use and from data inTable 6-6 from the DCM. Time of concentrations were developed using equations from DCM. Waterquality and detention pond will be sized per the full spectrum method presented in Chapter 13 of theDCM. All runoff calculations and applicable charts and graphs are included in Appendix A.

Table 1 - 1-hr Point Rainfall DataStorm Rainfall (in.)5-year 1.50

100-year 2.52

HYDRAULIC CRITERIAThe Rational Method and USDCM’s SF-2 and SF-3 forms were used to determine the runoff fromthe minor and major storms on the site, and the UDFCD UD-Detention v3.07 spreadsheet wasutilized for sizing the water quality and detention ponds as well as outlet structure. Manning’sequation was used to size the proposed drainage swales in this report.

DRAINAGE FACILITY DESIGN

FOUR STEP PROCESS TO MINIMIZE ADVERSE IMPACTS OF URBANIZATIONIn accordance with the Colorado Springs Drainage Criteria Manual, Volume 2 this site hasimplemented the four step process to minimize adverse impacts of urbanization. The four stepprocess includes reducing runoff volumes, treating the water quality capture volume (WQCV),stabilizing drainage ways, and implementing long-term source controls.

Step 1: The Tamlin Road Storage Facility development consists paved drive aisles and parkingspaces with lawn areas interspersed within the development which helps disconnect impervious areasand reduce runoff volumes. The IRF worksheet can be found in Appendix C.

Step 2: Water Quality treatment for this site is provided in two onsite full spectrum water quality anddetention ponds. Runoff from the site will be collected in vegetated swales and conveyed to thedetention ponds.

Step 3: Drainage fees will be paid with the platting of the site in order to help fund major drainageimprovements per the “Sand Creek Drainage Basin Planning Study”. These improvements helpstabilize the drainage way.

Step 4: BMP’s will be utilized to minimize off-site contaminants and to protect the downstreamreceiving waters. Site specific temporary source control BMPs that will be implemented include, butare not limited to, silt fencing placed around downstream areas of disturbance, construction vehicletracking pads at the entrances, designated vehicle fueling areas, covered storage areas, spillcontainment and control, etc. The permanent erosion control BMP’s include asphalt drives andparking, storm inlets and storm pipe.

WATER QUALITYDeveloped area within Basin A will be conveyed to Full Spectrum Water Quality and DetentionPond A, located along the site’s eastern boundary. Developed area within Basin B will be conveyedto Full Spectrum Water Quality and Detention Pond B, located in the site’s southwest corner alongTamlin Road. It should be noted that all proposed parking and drive aisles will be constructed ofgravel. However, there is a possibility of the owner paving the drive aisles and parking stalls withasphalt in the future. Therefore, all water quality and detention calculations are per the asphaltcondition.

Pond A has a total of 7.91 tributary acres for total detention basin volume of 1.055 ac-ft. Pond Autilizes a full spectrum outlet structure to detain the WQCV for a 40-hr period, the EURV for a 72-hour period and the 100-yr volume for 73-hr period. The outlet structure will release at less thanhistoric rates. Pond A will discharge into an energy dissipater located along the eastern property line.From here, discharge will maintain the sub-basins existing drainage patterns and discharge to vacantland to the east.

Pond B has a total of 5.61 tributary acres producing a total detention basin volume of 0.592 ac-ft.Pond B utilizes a full spectrum outlet structure to detain the WQCV for a 40-hr period, the EURV fora 72-hour period and the 100-yr volume for 72-hr period. The outlet structure will release at less thanhistoric rates. Pond B will discharge directly into an energy dissipater located along Tamlin Road.

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gravel

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Please revise step 3 as no drainage fees are due as this is a site development plan application. This should be relative to the project site.

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As designed, pond B drains in 76 hrs per the submitted calculation.

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Please indicate and analyze if the downstream swale is adequate due to the concentrated discharge from the pond.

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Assuming the dissipater is located in the ditch along tamlin road, Please analyze if the ditch is adequate and has the capacity for this concentrate discharge from the pond.

From here, discharge will maintain the sub-basins existing drainage patterns and discharge westacross Tamlin Road towards Eastview Estates Filing No. 3.

EROSION CONTROL PLANThe El Paso County Drainage Criteria Manual specifies an Erosion Control Plan and associated costestimate be submitted with the Final Drainage Report. We respectfully request that the ErosionControl Plan and Cost Estimate be submitted in conjunction with the grading and erosion controlplan and construction assurances posted prior to obtaining a grading permit.

OPERATION & MAINTENANCEIn order to ensure the function and effectiveness of the stormwater infrastructure, maintenanceactivities such as inspection, routine maintenance, restorative maintenance, rehabilitation and repair,are required. The property owner shall be responsible for the inspection, maintenance, rehabilitationand repair of stormwater and erosion control facilities located on the property unless another partyaccepts such responsibility in writing and responsibility is properly assigned through legaldocumentation. Access is provided from onsite facilities. An Inspection and Maintenance Manualwill accompany the Final Drainage Report submittal package.

FLOODPLAIN STATEMENTBased on the FEMA FIRM Map number 08041C0543G and 08041C0545G, the site does not fallwithin a FEMA defined floodplain and is classified as Zone X, which are areas determined to beoutside the 0.2% annual chance floodplain. FIRM maps of the site and surrounding areas have beenpresented in Appendix A.

DRAINAGE AND BRIDGE FEESThe site lies within the Sand Creek Drainage Basin. See Table 2 below for required drainage basinfees. Per El Paso County processes, Drainage fees are due at the time of platting. This developmentis not proposed to be platted and the fees shown in Table 2 below are for informational purposesonly. The fees are based on an asphalted site and have not taken into consideration pondconstruction credits for the two proposed detention ponds.

Table 2 – Basin Fees

Tamlin Road Storage Yard Drainage Basin Fees

TotalArea

Site %Imperviousness

ImperviousAcres

DrainageFee/Impervious

Acre

BridgeFee/Impervious

Acre

Total Fee -Drainageand Pond

16.5 54.50% 8.99 $18,940 $5,559 $220,246.01

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bridge

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CONSTRUCTION COST OPINIONSee Table 3 below for cost opinion of private storm sewer infrastructure.

Table 3 – Construction Cost Opinion

Private Drainage Facilities

Item Quantity Unit Unit Price Extended Cost12" RCP 80 LF $ 38.00 $ 3,040.0012" FES 2 EA $ 1,200.00 $ 2,400.00

FULL SPECTURMOUTLET STRUCTURE 2 LS $ 15,000.00 $ 30,000.00

Sub-Total $ 35,440.0010% Eng. And Contingency $ 3,544.00

Grand Total $ 38,984.00

SUMMARY

The proposed Tamlin Road Storage Facility drainage improvements include storm sewer, waterquality ponds, and engineered outfalls. The proposed development will not adversely affect theoffsite major drainageways or surrounding developments. This report is in conformance with thelatest El Paso County Storm Drainage Criteria requirements for this site.

REFERENCES

1. El Paso County Drainage Criteria Manual (Volumes I & II), El Paso County CO, Colorado,Updated May, 2014.

2. Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3), Urban Drainage and Flood ControlDistrict, June 2001.

3. “Hydrologic Group Rating for El Paso County Area, Colorado”, USDA-Natural ResourcesConservation Service, National Cooperative Soil Survey. Web Soil Survey URL:http://websoilsurvey.nrcs.usda.gov. [June 14, 2019]

4. “Sand Creek Drainage Basin Planning Study Final Design Report”, Kiowa EngineeringCorporation, March 1996.

http://websoilsurvey.nrcs.usda.gov.

FINAL DRAINAGE REPORT FORTAMLIN ROAD STORAGE FACILITY

Appendix AVicinity Map, Soil Descriptions, FEMA Floodplain Map

A Westrian Company

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Hydrologic Soil Group—El Paso County Area, Colorado

Natural ResourcesConservation Service

Web Soil SurveyNational Cooperative Soil Survey

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527510 527580 527650 527720 527790 527860 527930

527510 527580 527650 527720 527790 527860 527930

38° 54' 32'' N10

4° 4

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38° 54' 32'' N

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Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS840 100 200 400 600

Feet0 40 80 160 240

MetersMap Scale: 1:2,840 if printed on A portrait (8.5" x 11") sheet.

Soil Map may not be valid at this scale.

MAP LEGEND MAP INFORMATION

Area of Interest (AOI)Area of Interest (AOI)

SoilsSoil Rating Polygons

A

A/D

B

B/D

C

C/D

D

Not rated or not available

Soil Rating LinesA

A/D

B

B/D

C

C/D

D


Soil Rating PointsA

A/D

B

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Water FeaturesStreams and Canals

TransportationRails

Interstate Highways

US Routes

Major Roads

Local Roads

BackgroundAerial Photography

The soil surveys that comprise your AOI were mapped at 1:24,000.

Warning: Soil Map may not be valid at this scale.

Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale.

Please rely on the bar scale on each map sheet for map measurements.

Source of Map: Natural Resources Conservation ServiceWeb Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857)

Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: El Paso County Area, ColoradoSurvey Area Data: Version 16, Sep 10, 2018

Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

Date(s) aerial images were photographed: Apr 15, 2011—Aug 17, 2017

The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.




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Hydrologic Soil Group

Map unit symbol Map unit name Rating Acres in AOI Percent of AOI

97 Truckton sandy loam, 3 to 9 percent slopes

A 17.9 100.0%

Totals for Area of Interest 17.9 100.0%

Description

Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms.

The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows:

Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission.

Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission.

Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission.

Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission.

If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes.

Rating Options

Aggregation Method: Dominant Condition

Component Percent Cutoff: None Specified




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USGS The National Map: Orthoimagery. Data refreshed April, 2019.

National Flood Hazard Layer FIRMette

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SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT

SPECIAL FLOODHAZARD AREAS

Without Base Flood Elevation (BFE)Zone A, V, A99

With BFE or Depth Zone AE, AO, AH, VE, ARRegulatory Floodway

0.2% Annual Chance Flood Hazard, Areasof 1% annual chance flood with averagedepth less than one foot or with drainageareas of less than one square mile Zone XFuture Conditions 1% AnnualChance Flood Hazard Zone XArea with Reduced Flood Risk due toLevee. See Notes. Zone XArea with Flood Risk due to Levee Zone D

NO SCREEN Area of Minimal Flood Hazard Zone X

Area of Undetermined Flood Hazard Zone D

Channel, Culvert, or Storm SewerLevee, Dike, or Floodwall

Cross Sections with 1% Annual Chance17.5 Water Surface Elevation

Coastal Transect

Coastal Transect BaselineProfile BaselineHydrographic Feature

Base Flood Elevation Line (BFE)

Effective LOMRs

Limit of StudyJurisdiction Boundary

Digital Data AvailableNo Digital Data AvailableUnmapped

This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standardsThe flood hazard information is derived directly from theauthoritative NFHL web services provided by FEMA. This mapwas exported on 6/14/2019 at 10:33:46 AM and does notreflect changes or amendments subsequent to this date andtime. The NFHL and effective information may change orbecome superseded by new data over time.This map image is void if the one or more of the following mapelements do not appear: basemap imagery, flood zone labels,legend, scale bar, map creation date, community identifiers,FIRM panel number, and FIRM effective date. Map images forunmapped and unmodernized areas cannot be used forregulatory purposes.

Legend

OTHER AREAS OFFLOOD HAZARD

OTHER AREAS

GENERALSTRUCTURES

OTHERFEATURES

MAP PANELS

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FINAL DRAINAGE REPORT FORTAMLIN ROAD STORAGE YARD

Appendix BReference Material

18-470


Appendix CHydrologic Calculations

Tributary Area Percent tc Q5 Q100

Sub-basin (acres) Impervious C5 C100 (min) (cfs) (cfs)

A1 6.04 75% 0.70 0.81 9.5 17.7 34.5A2 0.80 59% 0.56 0.71 5.4 2.3 4.8A3 1.07 62% 0.59 0.73 6.6 3.0 6.2A4 1.48 6% 0.13 0.39 9.1 0.8 4.1A5 0.59 0% 0.08 0.35 5.0 0.2 1.8B1 4.30 66% 0.62 0.75 9.9 11.1 22.5B2 1.31 29% 0.32 0.53 9.2 1.8 4.9B3 0.90 0% 0.08 0.35 5.0 0.4 2.7

BASIN SUMMARY TABLE

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Tributary Q5 Q100

Sub-basin (cfs) (cfs)

1 17.7 34.52 2.3 4.83 3.0 6.24 0.8 4.15 0.2 1.86 11.1 22.57 1.8 4.98 0.4 2.7

POND A IN 22.9 45.5POND B IN 12.8 27.4

DESIGN POINTSUMMARY TABLE


Subdivision: TAMLIN ROAD STORAGE YARD Project Name: TAMLIN ROAD STORAGE YARDLocation: Colorado Springs Project No.:

Calculated By: NQJChecked By: 0

Date: 7/2/19

A1 6.04 100% 4.54 75.2% 90% 0.00 0.0% 0% 1.50 0.0% 75.2%

A2 0.80 100% 0.47 58.8% 90% 0.00 0.0% 0% 0.33 0.0% 58.8%

A3 1.07 100% 0.66 61.7% 90% 0.00 0.0% 0% 0.41 0.0% 61.7%

A4 1.48 100% 0.09 6.1% 90% 0.00 0.0% 0% 1.39 0.0% 6.1%

A5 0.59 100% 0.00 0.0% 90% 0.00 0.0% 0% 0.59 0.0% 0.0%

B1 4.30 100% 2.84 66.0% 90% 0.00 0.0% 0% 1.46 0.0% 66.0%

B2 1.31 100% 0.38 29.0% 90% 0.00 0.0% 0% 0.93 0.0% 29.0%

B3 0.90 100% 0.00 0.0% 90% 0.00 0.0% 0% 0.90 0.0% 0.0%

TOTAL 16.49 54.5%

POND A TOTAL 7.91 POND A 71.7%

POND B TOTAL 5.61 POND B 57.4%

COMPOSITE % IMPERVIOUS CALCULATIONS

Weighted% Imp.

Basins TotalWeighted %

Imp.Basin ID Total Area (ac) % Imp. Area (ac)

Lawns

% Imp. Area (ac)Weighted

% Imp.

Paved Roads (Asphalt) RoofsWeighted

% Imp.% Imp. Area (ac)

25134.00


dsdtorres

Text Box

Per the submitted landscape plan the majority of the landscape islands have rock as a surface material yet it does not appear to have been accounted for. For example basin B2, has a large of amount of these islands with rock yet it attributes 1.46 acres to lawn (0% impervious) and there is very little lawn in this basin. Please review the submitted landscape plan and adjust the calculations for all the basins accordingly.



Date: 7/2/19

A1 6.04 75.2% 6.04 0.00 0.00 4.54 0.00 1.50 0.90 0.73 0.08 0.96 0.81 0.35 0.70 0.81

A2 0.80 58.8% 0.80 0.00 0.00 0.47 0.00 0.33 0.90 0.73 0.08 0.96 0.81 0.35 0.56 0.71

A3 1.07 61.7% 1.07 0.00 0.00 0.66 0.00 0.41 0.90 0.73 0.08 0.96 0.81 0.35 0.59 0.73

A4 1.48 6.1% 1.48 0.00 0.00 0.09 0.00 1.39 0.90 0.73 0.08 0.96 0.81 0.35 0.13 0.39

A5 0.59 0.0% 0.59 0.00 0.00 0.00 0.00 0.59 0.90 0.73 0.08 0.96 0.81 0.35 0.08 0.35

B1 4.30 66.0% 4.30 0.00 0.00 2.84 0.00 1.46 0.90 0.73 0.08 0.96 0.81 0.35 0.62 0.75

B2 1.31 29.0% 1.31 0.00 0.00 0.38 0.00 0.93 0.90 0.73 0.08 0.96 0.81 0.35 0.32 0.53

B3 0.90 0.0% 0.90 0.00 0.00 0.00 0.00 0.90 0.90 0.73 0.08 0.96 0.81 0.35 0.08 0.35

TOTAL 16.49 54.5% 16.49 0.00 0.00 8.98 0.00 7.51 --- --- --- --- --- --- 0.53 0.68

Minor Coefficients Major Coefficients

C5,A,ROOFS C5,A, LAWNS C100,A. ROADS C100,A,ROOFS C100,A, LAWNS

COMPOSITE RUNOFF COEFFICIENT CALCULATIONS

Basins TotalWeighted C5

Basins TotalWeighted C100Basin ID

Area A(ac)

Area B(ac)

Area C/D(ac)

AreaRoads (ac)

AreaRoofs (ac)

AreaLawns (ac)

C5,A,ROADS

25134.00

Total Area(ac)

Basins TotalWeighted %

Imp.

Hydrologic Soil Group Land Use




Date: 7/2/19

FINAL

BASIN D.A. Hydrologic Impervious C5 C100 L S o t i L t S t K VEL. t t COMP. t c TOTAL Urbanized t c t c

ID (ac) Soils Group (%) (ft) (%) (min) (ft) (%) (ft/s) (min) (min) LENGTH (ft) (min) (min)

A1 6.04 A 75% 0.70 0.81 180 2.0% 7.8 430 4.3% 20.0 4.1 1.7 9.5 610.0 15.0 9.5

A2 0.80 A 59% 0.56 0.71 68 20.0% 3.0 350 1.5% 20.0 2.4 2.4 5.4 418.0 18.8 5.4

A3 1.07 A 62% 0.59 0.73 70 3.6% 5.1 280 2.3% 20.0 3.0 1.5 6.6 350.0 17.3 6.6

A4 1.48 A 6% 0.13 0.39 65 4.7% 8.5 105 8.0% 10.0 2.8 0.6 9.1 170.0 25.6 9.1

A5 0.59 A 0% 0.08 0.35 10 33.0% 1.8 25 33.0% 10.0 5.7 0.1 1.9 35.0 26.1 5.0

B1 4.30 A 66% 0.62 0.75 140 2.3% 7.8 520 4.0% 20.0 4.0 2.2 9.9 660.0 17.1 9.9

B2 1.31 A 29% 0.32 0.53 150 9.0% 8.4 280 8.0% 20.0 5.7 0.8 9.2 430.0 22.3 9.2

B3 0.90 A 0% 0.08 0.35 27 33.0% 3.0 150 3.3% 10.0 1.8 1.4 4.4 177.0 27.5 5.0

NOTES:

(URBANIZED BASINS)DATAINITIAL/OVERLAND

(Ti)TRAVEL TIME

(Tt)

STANDARD FORM SF-2TIME OF CONCENTRATION

SUB-BASIN tc CHECK

25134.00


Project Name: TAMLIN ROAD STORAGE YARDSubdivision: TAMLIN ROAD STORAGE YARD Project No.:

Location: Colorado Springs Calculated By: NQJDesign Storm: Checked By: 0

Date:

TRAVEL TIME

STREET

Desi

gn P

oint

Basi

n ID

Area

(Ac)

Runo

ff Co

eff.

t c (m

in)

C*A

(Ac)

I (in

/hr)

Q (c

fs)

tc (m

in)

C*A

(ac)

I (in

/hr)

Q (c

fs)

Qst

reet

(cfs

)

C*A

(ac)

Slop

e (%

)

Qpi

pe (c

fs)

C*A

(ac)

Slop

e (%

)

Pipe

Size

(inc

hes)

Leng

th (f

t)

Velo

city

(fps

)

t t (m

in) REMARKS

1 A1 6.04 0.70 9.5 4.21 4.21 17.7

2 A2 0.80 0.56 5.4 0.45 5.06 2.3

3 A3 1.07 0.59 6.6 0.63 4.75 3.0

4 A4 1.48 0.13 9.1 0.19 4.27 0.8

5 A5 0.59 0.08 5.0 0.05 5.17 0.3

6 B1 4.30 0.62 9.9 2.67 4.14 11.1

7 B2 1.31 0.32 9.2 0.42 4.25 1.8

8 B3 0.90 0.08 5.0 0.07 5.17 0.4

Notes:Street and Pipe C*A values are determined by Q/i using the catchment's intensity value.

BASIN B1 FLOW, CAPTURED IN SWALE,CONVEYED TO POND B.

BASIN B2 FLOW, SHEET FLOW TO POND B.

BASIN B3 (UNDEVELOPED) FLOW, SHEET FLOWWEST OFF SITE TO TAMLIN ROAD.

BASIN A2 FLOW. CAPTURED IN SWALE,CONVEYED TO POND A.

BASIN A1 FLOW. SHEET FLOW INTO POND A.

BASIN A3 FLOW, CAPTURED IN SWALE,CONVEYED TO POND A.

BASIN A4 (UNDEVELOPED) FLOW, SHEET FLOWEAST OFFSITE.


DIRECT RUNOFF TOTAL RUNOFF STREET PIPE

STANDARD FORM SF-3STORM DRAINAGE SYSTEM DESIGN

(RATIONAL METHOD PROCEDURE)

5-Year

25134.00

7/2/19


Project Name: TAMLIN ROAD STORAGE YARDSubdivision: TAMLIN ROAD STORAGE YARD Project No.:

Location: Colorado Springs Calculated By: NQJDesign Storm: Checked By: 0

Date:

TRAVEL TIME

STREET

Desig

n Po

int

Basin

ID

Area

(ac)

Runo

ff Co

eff.

t c (m

in)

C*A

(ac)

I (in

/hr)

Q (c

fs)

tc (m

in)

C*A

(ac)

I (in

/hr)

Q (c

fs)

Qst

reet

(cfs

)

C*A

(ac)

Slop

e (%

)

Qpi

pe (c

fs)

C*A

(ac)

Slop

e (%

)

Pipe

Siz

e (in

ches

)

Leng

th (f

t)

Velo

city

(fps

)

t t (m

in) REMARKS

1 A1 6.04 0.81 9.5 4.88 7.06 34.5

2 A2 0.80 0.71 5.4 0.57 8.50 4.8

3 A3 1.07 0.73 6.6 0.78 7.97 6.2

4 A4 1.48 0.39 9.1 0.57 7.17 4.1

5 A5 0.59 0.35 5.0 0.21 8.68 1.8

6 B1 4.30 0.75 9.9 3.24 6.95 22.5

7 B2 1.31 0.53 9.2 0.69 7.14 4.9

8 B3 0.90 0.35 5.0 0.32 8.68 2.8

Notes:Street and Pipe C*A values are determined by Q/i using the catchment's intensity value.

BASIN B1 FLOW, CAPTURED IN SWALE,CONVEYED TO POND B.

BASIN B2 FLOW, SHEET FLOW TO POND B.

BASIN B3 (UNDEVELOPED) FLOW, SHEET FLOWWEST OFF SITE TO TAMLIN ROAD.

BASIN A1 FLOW. SHEET FLOW INTO POND A.

BASIN A2 FLOW. CAPTURED IN SWALE,CONVEYED TO POND A.

BASIN A3 FLOW, CAPTURED IN SWALE,CONVEYED TO POND A.



STORM DRAINAGE SYSTEM DESIGNSTANDARD FORM SF-3

(RATIONAL METHOD PROCEDURE)

25134.00

PIPE

100-Year

DIRECT RUNOFF TOTAL RUNOFF

7/2/19

STREET



Appendix DHydraulic Calculations

Channel Report

Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Jul 10 2019

BASIN A - DRAINAGE SWALE NORTH - Q_100 = 4.8 cfs

TrapezoidalBottom Width (ft) = 1.00Side Slopes (z:1) = 7.70, 4.00Total Depth (ft) = 1.60Invert Elev (ft) = 6700.00Slope (%) = 1.06N-Value = 0.030

CalculationsCompute by: Known QKnown Q (cfs) = 4.80

HighlightedDepth (ft) = 0.53Q (cfs) = 4.800Area (sqft) = 2.17Velocity (ft/s) = 2.21Wetted Perim (ft) = 7.30Crit Depth, Yc (ft) = 0.46Top Width (ft) = 7.20EGL (ft) = 0.61

0 2 4 6 8 10 12 14 16 18 20 22 24

Elev (ft) Depth (ft)Section

6699.50 -0.50

6700.00 0.00

6700.50 0.50

6701.00 1.00

6701.50 1.50

6702.00 2.00

Reach (ft)

Channel Report


BASIN A - DRAINAGE SWALE SOUTH - Q_100 = 6.2 cfs




0 2 4 6 8 10 12 14 16 18 20 22 24


6699.50 -0.50

6700.00 0.00

6700.50 0.50

6701.00 1.00

6701.50 1.50

6702.00 2.00

Reach (ft)

Channel Report


BASIN B - DRAINAGE SWALE - Q_100 = 22.5 cfs




0 5 10 15 20 25 30 35 40 45 50 55 60


6699.50 -0.50

6700.00 0.00

6700.50 0.50

6701.00 1.00

6701.50 1.50

6702.00 2.00

6702.50 2.50

6703.00 3.00

Reach (ft)

dsdtorres

Callout

Provide protection for this grass swale as the velocity is exceeding the permissible velocity

Weir Report


Pond A Spillway (Q_100_undetained = 29.8 cfs per UD-Detention Peak Inflow)

Trapezoidal WeirCrest = SharpBottom Length (ft) = 100.00Total Depth (ft) = 1.21Side Slope (z:1) = 4.00

CalculationsWeir Coeff. Cw = 3.10Compute by: Known QKnown Q (cfs) = 29.80

HighlightedDepth (ft) = 0.21Q (cfs) = 29.80Area (sqft) = 21.18Velocity (ft/s) = 1.41Top Width (ft) = 101.68

0 10 20 30 40 50 60 70 80 90 100 110 120 130

Depth (ft) Depth (ft)Pond A Spillway (Q_100_undetained = 29.8 cfs per UD-Detention Peak Inflow)

-0.50 -0.50

0.00 0.00

0.50 0.50

1.00 1.00

1.50 1.50

2.00 2.00

Length (ft)Weir W.S.

Weir Report


Pond B Spillway (Q_100_undetained = 12.8 cfs per UD-Detention Peak Inflow Q)

Trapezoidal WeirCrest = SharpBottom Length (ft) = 20.00Total Depth (ft) = 1.34Side Slope (z:1) = 4.00

CalculationsWeir Coeff. Cw = 3.10Compute by: Known QKnown Q (cfs) = 12.80

HighlightedDepth (ft) = 0.34Q (cfs) = 12.80Area (sqft) = 7.26Velocity (ft/s) = 1.76Top Width (ft) = 22.72

0 5 10 15 20 25 30 35 40 45

Depth (ft) Depth (ft)Pond B Spillway (Q_100_undetained = 12.8 cfs per UD-Detention Peak Inflow Q)

-0.50 -0.50

0.00 0.00

0.50 0.50

1.00 1.00

1.50 1.50

2.00 2.00

Length (ft)Weir W.S.


Appendix EWater Quality and Detention

Project:

Basin ID:

Depth Increment = ft

Required Volume Calculation 6716.7 Top of Micropool -- 0.00 -- -- -- 0 0.000

Selected BMP Type = EDB 6717 -- 0.30 -- -- -- 380 0.009 53 0.001

Watershed Area = 7.91 acres 6718 -- 1.30 -- -- -- 2,653 0.061 1,547 0.036

Watershed Length = 600 ft 6719 -- 2.30 -- -- -- 5,807 0.133 5,803 0.133

Watershed Slope = 0.050 ft/ft 6720 -- 3.30 -- -- -- 9,841 0.226 13,627 0.313

Watershed Imperviousness = 71.70% percent 6721 -- 4.30 -- -- -- 13,085 0.300 25,090 0.576

Percentage Hydrologic Soil Group A = 100.0% percent 6722 -- 5.30 -- -- -- 16,257 0.373 39,761 0.913

Percentage Hydrologic Soil Group B = 0.0% percent 6722.5 -- 5.80 -- -- -- 17,822 0.409 48,281 1.108

Percentage Hydrologic Soil Groups C/D = 0.0% percent 6723.7 -- -- -- --

Desired WQCV Drain Time = 40.0 hours -- -- -- --

Location for 1-hr Rainfall Depths = User Input -- -- -- --

Water Quality Capture Volume (WQCV) = 0.186 acre-feet -- -- -- --

Excess Urban Runoff Volume (EURV) = 0.723 acre-feet -- -- -- --

2-yr Runoff Volume (P1 = 1.19 in.) = 0.499 acre-feet 1.19 inches -- -- -- --



25-yr Runoff Volume (P1 = 2 in.) = 0.944 acre-feet 2.00 inches -- -- -- --



500-yr Runoff Volume (P1 = 0 in.) = 0.000 acre-feet inches -- -- -- --

Approximate 2-yr Detention Volume = 0.473 acre-feet -- -- -- --






-- -- -- --

Stage-Storage Calculation -- -- -- --

Zone 1 Volume (WQCV) = 0.186 acre-feet -- -- -- --

Zone 2 Volume (EURV - Zone 1) = 0.537 acre-feet -- -- -- --

Zone 3 Volume (100-year - Zones 1 & 2) = 0.332 acre-feet -- -- -- --

Total Detention Basin Volume = 1.055 acre-feet -- -- -- --

Initial Surcharge Volume (ISV) = user ft 3̂ -- -- -- --

Initial Surcharge Depth (ISD) = user ft -- -- -- --

Total Available Detention Depth (Htotal) = user ft -- -- -- --Depth of Trickle Channel (HTC) = user ft -- -- -- --

Slope of Trickle Channel (STC) = user ft/ft -- -- -- --

Slopes of Main Basin Sides (Smain) = user H:V -- -- -- --

Basin Length-to-Width Ratio (RL/W) = user -- -- -- --

-- -- -- --

Initial Surcharge Area (AISV) = user ft 2̂ -- -- -- --

Surcharge Volume Length (LISV) = user ft -- -- -- --

Surcharge Volume Width (W ISV) = user ft -- -- -- --

Depth of Basin Floor (HFLOOR) = user ft -- -- -- --

Length of Basin Floor (LFLOOR) = user ft -- -- -- --

Width of Basin Floor (WFLOOR) = user ft -- -- -- --

Area of Basin Floor (AFLOOR) = user ft 2̂ -- -- -- --

Volume of Basin Floor (VFLOOR) = user ft 3̂ -- -- -- --

Depth of Main Basin (HMAIN) = user ft -- -- -- --

Length of Main Basin (LMAIN) = user ft -- -- -- --

Width of Main Basin (WMAIN) = user ft -- -- -- --

Area of Main Basin (AMAIN) = user ft 2̂ -- -- -- --

Volume of Main Basin (VMAIN) = user ft 3̂ -- -- -- --

Calculated Total Basin Volume (Vtotal) = user acre-feet -- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- --

Optional User Override1-hr Precipitation

Volume(ft 3̂)

Volume(ac-ft)

Area(acre)

DETENTION BASIN STAGE-STORAGE TABLE BUILDER

OptionalOverride

Area (ft 2̂)Length

(ft)

OptionalOverrideStage (ft)

Stage(ft)

Stage - StorageDescription

Area(ft 2̂)

Width(ft)

TAMLIN ROAD STORAGE FACILITY

BASIN A

UD-Detention, Version 3.07 (February 2017)

Example Zone Configuration (Retention Pond)

Basin A_asphalt_UD-Detention_v3.07.xlsm, Basin 7/3/2019, 9:21 AM

dsdtorres

Callout

update accordingly per comments on composite impervious calculation

1 User Defined Stage-Area Boolean for Message

1 Equal Stage-Area Inputs Watershed L:W

1 CountA

0 Calc_S_TC

H_FLOOR

L_FLOOR_OTHER

0.00 ISV 0.00 ISV

0.00 Floor 0.00 Floor

2.66 Zone 1 (WQCV) 2.66 Zone 1 (WQCV)

4.77 Zone 2 (EURV) 4.77 Zone 2 (EURV)

5.67 Zone 3 (100-year) 5.67 Zone 3 (100-year)



0.000

0.280

0.560

0.840

1.120

0.000

0.105

0.210

0.315

0.420

0.00 1.50 3.00 4.50 6.00

Volu

me

(ac-

ft)

Area

(acr

es)

Stage (ft.)

Area (acres) Volume (ac-ft)

0

100

200

300

400

0

5

10

15

20

0.00 1.50 3.00 4.50 6.00

Area

(sq

.ft.)

Leng

th, W

idth

(ft.)

Stage (ft)

Length (ft) Width (ft) Area (sq.ft.)

Basin A_asphalt_UD-Detention_v3.07.xlsm, Basin 7/3/2019, 9:21 AM

Project: Basin ID:

Stage (ft) Zone Volume (ac-ft) Outlet Type

Zone 1 (WQCV) 2.66 0.186 Orifice Plate

Zone 2 (EURV) 4.77 0.537 Orifice Plate

Zone 3 (100-year) 5.67 0.332 Weir&Pipe (Restrict)

1.055 TotalUser Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP) Calculated Parameters for Underdrain

Underdrain Orifice Invert Depth = N/A ft (distance below the filtration media surface) Underdrain Orifice Area = N/A ft2

Underdrain Orifice Diameter = N/A inches Underdrain Orifice Centroid = N/A feet

User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV in a sedimentation BMP) Calculated Parameters for PlateInvert of Lowest Orifice = 0.00 ft (relative to basin bottom at Stage = 0 ft) WQ Orifice Area per Row = N/A ft2

Depth at top of Zone using Orifice Plate = 4.77 ft (relative to basin bottom at Stage = 0 ft) Elliptical Half-Width = N/A feetOrifice Plate: Orifice Vertical Spacing = N/A inches Elliptical Slot Centroid = N/A feet

Orifice Plate: Orifice Area per Row = N/A inches Elliptical Slot Area = N/A ft2

User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest)Row 1 (required) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row 5 (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional)

Stage of Orifice Centroid (ft) 0.00 1.59 3.00

Orifice Area (sq. inches) 1.02 1.10 3.20

Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional)

Stage of Orifice Centroid (ft)

Orifice Area (sq. inches)

User Input: Vertical Orifice (Circular or Rectangular) Calculated Parameters for Vertical OrificeNot Selected Not Selected Not Selected Not Selected

Invert of Vertical Orifice = N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Area = N/A N/A ft2

Depth at top of Zone using Vertical Orifice = N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Centroid = N/A N/A feetVertical Orifice Diameter = N/A N/A inches

User Input: Overflow Weir (Dropbox) and Grate (Flat or Sloped) Calculated Parameters for Overflow WeirZone 3 Weir Not Selected Zone 3 Weir Not Selected

Overflow Weir Front Edge Height, Ho = 4.77 N/A ft (relative to basin bottom at Stage = 0 ft) Height of Grate Upper Edge, Ht = 4.77 N/A feetOverflow Weir Front Edge Length = 3.00 N/A feet Over Flow Weir Slope Length = 3.00 N/A feet

Overflow Weir Slope = 0.00 N/A H:V (enter zero for flat grate) Grate Open Area / 100-yr Orifice Area = 13.85 N/A should be > 4Horiz. Length of Weir Sides = 3.00 N/A feet Overflow Grate Open Area w/o Debris = 6.30 N/A ft2

Overflow Grate Open Area % = 70% N/A %, grate open area/total area Overflow Grate Open Area w/ Debris = 3.15 N/A ft2

Debris Clogging % = 50% N/A %

User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice) Calculated Parameters for Outlet Pipe w/ Flow Restriction PlateZone 3 Restrictor Not Selected Zone 3 Restrictor Not Selected

Depth to Invert of Outlet Pipe = 0.96 N/A ft (distance below basin bottom at Stage = 0 ft) Outlet Orifice Area = 0.46 N/A ft2

Outlet Pipe Diameter = 12.00 N/A inches Outlet Orifice Centroid = 0.32 N/A feetRestrictor Plate Height Above Pipe Invert = 6.75 inches Half-Central Angle of Restrictor Plate on Pipe = 1.70 N/A radians

User Input: Emergency Spillway (Rectangular or Trapezoidal) Calculated Parameters for SpillwaySpillway Invert Stage= 5.84 ft (relative to basin bottom at Stage = 0 ft) Spillway Design Flow Depth= 0.21 feet

Spillway Crest Length = 100.00 feet Stage at Top of Freeboard = 7.05 feetSpillway End Slopes = 4.00 H:V Basin Area at Top of Freeboard = 0.41 acres

Freeboard above Max Water Surface = 1.00 feet

Routed Hydrograph ResultsDesign Storm Return Period = WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 YearOne-Hour Rainfall Depth (in) = 0.53 1.07 1.19 1.50 1.75 2.00 2.25 2.52 0.00

Calculated Runoff Volume (acre-ft) = 0.186 0.723 0.499 0.650 0.788 0.944 1.108 1.300 0.000OPTIONAL Override Runoff Volume (acre-ft) =

Inflow Hydrograph Volume (acre-ft) = 0.186 0.724 0.499 0.650 0.788 0.944 1.108 1.301 #N/APredevelopment Unit Peak Flow, q (cfs/acre) = 0.00 0.00 0.00 0.01 0.02 0.04 0.30 0.73 0.00

Predevelopment Peak Q (cfs) = 0.0 0.0 0.0 0.1 0.1 0.3 2.4 5.7 0.0Peak Inflow Q (cfs) = 4.4 16.7 11.6 15.0 18.2 21.7 25.5 29.8 #N/A

Peak Outflow Q (cfs) = 0.1 0.3 0.2 0.3 0.7 3.5 5.3 5.5 #N/ARatio Peak Outflow to Predevelopment Q = N/A N/A N/A 4.2 4.9 10.5 2.2 0.9 #N/A

Structure Controlling Flow = Plate Plate Plate Plate Overflow Grate 1 Overflow Grate 1 Outlet Plate 1 Outlet Plate 1 #N/AMax Velocity through Grate 1 (fps) = N/A N/A N/A N/A 0.1 0.5 0.8 0.8 #N/AMax Velocity through Grate 2 (fps) = N/A N/A N/A N/A N/A N/A N/A N/A #N/A

Time to Drain 97% of Inflow Volume (hours) = 39 67 59 64 68 67 65 64 #N/ATime to Drain 99% of Inflow Volume (hours) = 40 72 63 70 74 74 73 73 #N/A

Maximum Ponding Depth (ft) = 2.59 4.68 3.95 4.45 4.83 5.02 5.22 5.55 #N/AArea at Maximum Ponding Depth (acres) = 0.16 0.33 0.27 0.31 0.34 0.35 0.37 0.39 #N/A

Maximum Volume Stored (acre-ft) = 0.176 0.692 0.475 0.619 0.745 0.808 0.880 1.008 #N/A

Detention Basin Outlet Structure DesignUD-Detention, Version 3.07 (February 2017)

TAMLIN ROAD STORAGE YARDBASIN A


dsdtorres

Callout

Adjust the design so that the release is equal to or less than pre-development

COUNTA for Basin Tab = 1 Ao Dia WQ Plate Type Vert Orifice 1 Vert Orifice 2Count_Underdrain = 0 0.11 (diameter = 3/8 inch) 2 1 1

Count_WQPlate = 1 0.14(diameter = 7/16 inch)

Count_VertOrifice1 = 0 0.18 (diameter = 1/2 inch) Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean

Count_VertOrifice2 = 0 0.24(diameter = 9/16 inch) 4 1 5yr, <72hr 0

Count_Weir1 = 1 0.29 (diameter = 5/8 inch) >5yr, <120hr #N/A 0

Count_Weir2 = 0 0.36(diameter = 11/16 inch) Max Depth Row

Count_OutletPipe1 = 1 0.42 (diameter = 3/4 inch) WQCV 260 Watershed Constraint Check

Count_OutletPipe2 = 0 0.50(diameter = 13/16 inch) 2 Year 396 Slope 0.040

COUNTA_2 (Standard FSD Setup)= 1 0.58 (diameter = 7/8 inch) EURV 469 Shape 1.04

MaxPondDepth_Error? FALSE 0.67(diameter = 15/16 inch) 5 Year 446Hidden Parameters & Calculations 0.76 (diameter = 1 inch) 10 Year 484 Spillway Depth

0.86(diameter = 1-1/16 inches) 25 Year 503 0.21WQ Plate Flow at 100yr depth = 0.32 0.97(diameter = 1-1/8 inches) 50 Year 523

CLOG #1= 35% 1.08(diameter = 1-3/16 inches) 100 Year 556 1 Z1_Boolean

Cdw #1 = 1.15 1.20(diameter = 1-1/4 inches) 500 Year #N/A 1 Z2_Boolean

Cdo #1 = 1.07 1.32(diameter = 1-5/16 inches) Zone3_Pulldown Message 1 Z3_Boolean

Overflow Weir #1 Angle = 0.000 1.45(diameter = 1-3/8 inches) 1 Opening Message

CLOG #2= #VALUE! 1.59(diameter = 1-7/16 inches) Draintime Running

Cdw #2 = #VALUE! 1.73(diameter = 1-1/2 inches) Outlet Boolean Outlet Rank Total (1 to 4)

Cdo #2 = #VALUE! 1.88(diameter = 1-9/16 inches) Vertical Orifice 1 0 0 1

Overflow Weir #2 Angle = #VALUE! 2.03(diameter = 1-5/8 inches) Vertical Orifice 2 0 0 Boolean

Underdrain Q at 100yr depth = 0.00 2.20(diameter = 1-11/16 inches) Overflow Weir 1 1 1 0 Max Depth

VertOrifice1 Q at 100yr depth = 0.00 2.36(diameter = 1-3/4 inches) Overflow Weir 2 0 0 0 500yr Depth

VertOrifice2 Q at 100yr depth = 0.00 2.54(diameter = 1-13/16 inches) Outlet Pipe 1 1 1 0 Freeboard

EURV_draintime_user = 2.72(diameter = 1-7/8 inches) Outlet Pipe 2 0 0 1 Spillway

Count_User_Hydrographs #N/A 2.90(diameter = 1-15/16 inches) 0 Spillway Length

CountA_3 (EURV & 100yr) = 1 3.09(diameter = 2 inches) Button Visibility Boolean FALSE Time Interval

CountA_4 (100yr Only) = 1 3.29(use rectangular openings) 1 Button_Trigger

0 Underdrain

1 WQCV Plate

0 EURV-WQCV Plate

0 EURV-WQCV VertOrifice

1 Outlet 90% Qpeak0 Outlet Undetained

S-A-V-D Chart Axis Override X-axis Left Y-Axis Right Y-Axisminimum bound

maximum bound


Detention Basin Outlet Structure Design

0

5

10

15

20

25

30

35

0.1 1 10

FLO

W [

cfs]

TIME [hr]

500YR IN

500YR OUT

100YR IN

100YR OUT

50YR IN

50YR OUT

25YR IN

25YR OUT

10YR IN

10YR OUT

5YR IN

5YR OUT

2YR IN

2YR OUT

EURV IN

EURV OUT

WQCV IN

WQCV OUT

0

1

2

3

4

5

6

0.1 1 10 100

PON

DIN

G D

EPTH

[ft]

DRAIN TIME [hr]

500YR

100YR

50YR

25YR

10YR

5YR

2YR

EURV

WQCV

0.00

1.00

2.00

3.00

4.00

5.00

6.00

0

10,000

20,000

30,000

40,000

50,000

60,000

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00

OU

TFLO

W [c

fs]

AREA

[ft^

2], V

OLU

ME

[ft^

3]

PONDING DEPTH [ft]

User Area [ft^2]

Interpolated Area [ft^2]

Summary Area [ft^2]

Volume [ft^3]

Summary Volume [ft^3]

Outflow [cfs]

Summary Outflow [cfs]

Outflow Hydrograph Workbook Filename:

Storm Inflow Hydrographs

The user can override the calculated inflow hydrographs from this workbook with inflow hydrographs developed in a separate program.

SOURCE WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK #N/A

Time Interval TIME WQCV [cfs] EURV [cfs] 2 Year [cfs] 5 Year [cfs] 10 Year [cfs] 25 Year [cfs] 50 Year [cfs] 100 Year [cfs] 500 Year [cfs]

3.59 min 0:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A

0:03:35 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A

Hydrograph 0:07:11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A

Constant 0:10:46 0.20 0.74 0.52 0.67 0.80 0.95 1.11 1.30 #N/A

1.394 0:14:22 0.53 1.99 1.39 1.79 2.16 2.58 3.02 3.53 #N/A0:17:57 1.36 5.12 3.56 4.61 5.56 6.63 7.75 9.06 #N/A0:21:32 3.75 14.06 9.79 12.66 15.28 18.22 21.29 24.89 #N/A

0:25:08 4.38 16.71 11.58 15.03 18.18 21.74 25.47 29.84 #N/A0:28:43 4.16 15.96 11.05 14.34 17.36 20.77 24.34 28.54 #N/A

0:32:19 3.79 14.53 10.05 13.05 15.81 18.91 22.16 25.98 #N/A0:35:54 3.36 12.98 8.97 11.66 14.13 16.92 19.84 23.28 #N/A0:39:29 2.87 11.22 7.73 10.07 12.22 14.65 17.19 20.19 #N/A0:43:05 2.51 9.77 6.74 8.77 10.64 12.75 14.95 17.55 #N/A0:46:40 2.27 8.85 6.10 7.95 9.64 11.55 13.56 15.91 #N/A0:50:16 1.85 7.31 5.02 6.56 7.97 9.57 11.25 13.22 #N/A0:53:51 1.49 5.98 4.09 5.36 6.52 7.84 9.23 10.86 #N/A0:57:26 1.13 4.61 3.14 4.13 5.04 6.08 7.17 8.46 #N/A1:01:02 0.82 3.44 2.33 3.07 3.76 4.55 5.39 6.39 #N/A1:04:37 0.60 2.49 1.69 2.23 2.72 3.29 3.91 4.66 #N/A1:08:13 0.47 1.93 1.31 1.72 2.10 2.54 3.01 3.56 #N/A1:11:48 0.39 1.58 1.08 1.42 1.73 2.09 2.47 2.92 #N/A1:15:23 0.33 1.34 0.92 1.20 1.47 1.77 2.09 2.47 #N/A1:18:59 0.29 1.18 0.81 1.06 1.29 1.55 1.83 2.16 #N/A

1:22:34 0.27 1.06 0.73 0.95 1.16 1.39 1.64 1.94 #N/A1:26:10 0.25 0.98 0.67 0.88 1.07 1.28 1.51 1.78 #N/A1:29:45 0.18 0.72 0.49 0.64 0.78 0.94 1.11 1.31 #N/A1:33:20 0.13 0.53 0.36 0.47 0.57 0.69 0.81 0.96 #N/A1:36:56 0.10 0.39 0.26 0.35 0.42 0.51 0.60 0.71 #N/A1:40:31 0.07 0.28 0.19 0.25 0.31 0.37 0.44 0.52 #N/A1:44:07 0.05 0.20 0.14 0.18 0.22 0.27 0.32 0.38 #N/A

1:47:42 0.03 0.14 0.10 0.13 0.16 0.19 0.23 0.27 #N/A1:51:17 0.02 0.10 0.07 0.09 0.11 0.14 0.16 0.19 #N/A1:54:53 0.02 0.07 0.05 0.06 0.07 0.09 0.11 0.13 #N/A1:58:28 0.01 0.04 0.03 0.04 0.04 0.05 0.07 0.08 #N/A2:02:04 0.00 0.02 0.01 0.02 0.02 0.03 0.03 0.04 #N/A2:05:39 0.00 0.01 0.00 0.01 0.01 0.01 0.01 0.02 #N/A2:09:14 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:12:50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:16:25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:20:01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:23:36 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:27:11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:30:47 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:34:22 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:37:58 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:41:33 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:45:08 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:48:44 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:52:19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:55:55 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A2:59:30 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A

3:03:05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A


3:56:56 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A4:00:32 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A4:04:07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A4:07:43 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A

4:11:18 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A4:14:53 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A4:18:29 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A



Summary Stage-Area-Volume-Discharge RelationshipsThe user can create a summary S-A-V-D by entering the desired stage increments and the remainder of the table will populate automatically.

The user should graphically compare the summary S-A-V-D table to the full S-A-V-D table in the chart to confirm it captures all key transition points.

Stage Area Area Volume Volume TotalOutflow

[ft] [ft^2] [acres] [ft^3] [ac-ft] [cfs]

0.00 0 0.000 0 0.000 0.00

0.50 812 0.019 170 0.004 0.02

1.00 1,948 0.045 860 0.020 0.03

1.50 3,252 0.075 2,134 0.049 0.04

2.00 4,829 0.111 4,155 0.095 0.07

2.50 6,614 0.152 7,046 0.162 0.09

2.71 7,461 0.171 8,523 0.196 0.10

3.00 8,631 0.198 10,857 0.249 0.10

3.50 10,490 0.241 15,661 0.360 0.19

4.00 12,112 0.278 21,311 0.489 0.23

4.50 13,719 0.315 27,771 0.638 0.27

4.90 14,988 0.344 33,512 0.769 1.50

5.00 15,305 0.351 35,027 0.804 3.15

5.50 16,883 0.388 43,075 0.989 5.43

5.84 17,822 0.409 48,281 1.108 5.56

6.00 17,822 0.409 48,281 1.108 5.56

6.50 17,822 0.409 48,281 1.108 5.56

7.00 17,822 0.409 48,281 1.108 5.56


WQCV

EURV

100-YEAR



For best results, include thestages of all grade slopechanges (e.g. ISV and Floor)from the S-A-V table onSheet 'Basin'.

Also include the inverts of alloutlets (e.g. vertical orifice,overflow grate, and spillway,where applicable).

Project:

Basin ID:


Required Volume Calculation 6711.74 Top of Micropool -- 0.00 -- -- -- 0 0.000

Selected BMP Type = EDB 6712 -- 0.26 -- -- -- 462 0.011 55 0.001

Watershed Area = 5.61 acres 6713 -- 1.26 -- -- -- 7,015 0.161 3,729 0.086

Watershed Length = 840 ft 6714 -- 2.26 -- -- -- 9,304 0.214 11,958 0.275

Watershed Slope = 0.050 ft/ft 6715 -- 3.26 -- -- -- 10,935 0.251 22,077 0.507

Watershed Imperviousness = 57.40% percent 6715.6 -- 3.96 -- -- -- 11,492 0.264 29,927 0.687

Percentage Hydrologic Soil Group A = 100.0% percent -- -- -- --

Percentage Hydrologic Soil Group B = 0.0% percent -- -- -- --

Percentage Hydrologic Soil Groups C/D = 0.0% percent -- -- -- --




Excess Urban Runoff Volume (EURV) = 0.386 acre-feet -- -- -- --




25-yr Runoff Volume (P1 = 2 in.) = 0.520 acre-feet 2.00 inches -- -- -- --



500-yr Runoff Volume (P1 = 0 in.) = 0.000 acre-feet inches -- -- -- --







-- -- -- --

Stage-Storage Calculation -- -- -- --

Zone 1 Volume (WQCV) = 0.106 acre-feet -- -- -- --

Zone 2 Volume (EURV - Zone 1) = 0.279 acre-feet -- -- -- --

Zone 3 Volume (100-year - Zones 1 & 2) = 0.206 acre-feet -- -- -- --

Total Detention Basin Volume = 0.592 acre-feet -- -- -- --

Initial Surcharge Volume (ISV) = user ft 3̂ -- -- -- --

Initial Surcharge Depth (ISD) = user ft -- -- -- --

Total Available Detention Depth (Htotal) = user ft -- -- -- --Depth of Trickle Channel (HTC) = user ft -- -- -- --

Slope of Trickle Channel (STC) = user ft/ft -- -- -- --

Slopes of Main Basin Sides (Smain) = user H:V -- -- -- --

Basin Length-to-Width Ratio (RL/W) = user -- -- -- --

-- -- -- --

Initial Surcharge Area (AISV) = user ft 2̂ -- -- -- --

Surcharge Volume Length (LISV) = user ft -- -- -- --

Surcharge Volume Width (W ISV) = user ft -- -- -- --

Depth of Basin Floor (HFLOOR) = user ft -- -- -- --

Length of Basin Floor (LFLOOR) = user ft -- -- -- --

Width of Basin Floor (WFLOOR) = user ft -- -- -- --

Area of Basin Floor (AFLOOR) = user ft 2̂ -- -- -- --

Volume of Basin Floor (VFLOOR) = user ft 3̂ -- -- -- --

Depth of Main Basin (HMAIN) = user ft -- -- -- --

Length of Main Basin (LMAIN) = user ft -- -- -- --

Width of Main Basin (WMAIN) = user ft -- -- -- --

Area of Main Basin (AMAIN) = user ft 2̂ -- -- -- --

Volume of Main Basin (VMAIN) = user ft 3̂ -- -- -- --

Calculated Total Basin Volume (Vtotal) = user acre-feet -- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- --


OptionalOverride

Area (ft 2̂)Length

(ft)


Stage(ft)


Area(ft 2̂)

Width(ft)


BASIN B


Volume(ft 3̂)

Volume(ac-ft)

Area(acre)

Optional User Override1-hr Precipitation


Basin B_UD-Detention_v3.07.xlsm, Basin 7/3/2019, 11:05 AM

dsdtorres

Callout

update accordingly per comments on composite impervious calculation

1 User Defined Stage-Area Boolean for Message

1 Equal Stage-Area Inputs Watershed L:W

1 CountA

0 Calc_S_TC

H_FLOOR

L_FLOOR_OTHER

0.00 ISV 0.00 ISV

0.00 Floor 0.00 Floor

1.38 Zone 1 (WQCV) 1.38 Zone 1 (WQCV)

2.76 Zone 2 (EURV) 2.76 Zone 2 (EURV)

3.60 Zone 3 (100-year) 3.60 Zone 3 (100-year)



0.000

0.175

0.350

0.525

0.700

0.000

0.070

0.140

0.210

0.280

0.00 1.00 2.00 3.00 4.00

Volu

me

(ac-

ft)

Area

(acr

es)

Stage (ft.)

Area (acres) Volume (ac-ft)

0

100

200

300

400

0

5

10

15

20

0.00 1.00 2.00 3.00 4.00

Area

(sq

.ft.)

Leng

th, W

idth

(ft.)

Stage (ft)

Length (ft) Width (ft) Area (sq.ft.)

Basin B_UD-Detention_v3.07.xlsm, Basin 7/3/2019, 11:05 AM

Project: Basin ID:

Stage (ft) Zone Volume (ac-ft) Outlet Type

Zone 1 (WQCV) 1.38 0.106 Orifice Plate

Zone 2 (EURV) 2.76 0.279 Orifice Plate

Zone 3 (100-year) 3.60 0.206 Weir&Pipe (Restrict)

0.592 TotalUser Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP) Calculated Parameters for Underdrain

Underdrain Orifice Invert Depth = N/A ft (distance below the filtration media surface) Underdrain Orifice Area = N/A ft2

Underdrain Orifice Diameter = N/A inches Underdrain Orifice Centroid = N/A feet

User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV in a sedimentation BMP) Calculated Parameters for PlateInvert of Lowest Orifice = 0.00 ft (relative to basin bottom at Stage = 0 ft) WQ Orifice Area per Row = N/A ft2

Depth at top of Zone using Orifice Plate = 2.76 ft (relative to basin bottom at Stage = 0 ft) Elliptical Half-Width = N/A feetOrifice Plate: Orifice Vertical Spacing = N/A inches Elliptical Slot Centroid = N/A feet

Orifice Plate: Orifice Area per Row = N/A inches Elliptical Slot Area = N/A ft2

User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest)Row 1 (required) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row 5 (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional)

Stage of Orifice Centroid (ft) 0.00 0.92 1.65

Orifice Area (sq. inches) 0.86 0.86 2.00

Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional)

Stage of Orifice Centroid (ft)

Orifice Area (sq. inches)

User Input: Vertical Orifice (Circular or Rectangular) Calculated Parameters for Vertical OrificeNot Selected Not Selected Not Selected Not Selected

Invert of Vertical Orifice = N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Area = N/A N/A ft2

Depth at top of Zone using Vertical Orifice = N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Centroid = N/A N/A feetVertical Orifice Diameter = N/A N/A inches

User Input: Overflow Weir (Dropbox) and Grate (Flat or Sloped) Calculated Parameters for Overflow WeirZone 3 Weir Not Selected Zone 3 Weir Not Selected

Overflow Weir Front Edge Height, Ho = 3.00 N/A ft (relative to basin bottom at Stage = 0 ft) Height of Grate Upper Edge, Ht = 3.00 N/A feetOverflow Weir Front Edge Length = 3.00 N/A feet Over Flow Weir Slope Length = 3.00 N/A feet

Overflow Weir Slope = 0.00 N/A H:V (enter zero for flat grate) Grate Open Area / 100-yr Orifice Area = 27.49 N/A should be > 4Horiz. Length of Weir Sides = 3.00 N/A feet Overflow Grate Open Area w/o Debris = 6.30 N/A ft2

Overflow Grate Open Area % = 70% N/A %, grate open area/total area Overflow Grate Open Area w/ Debris = 3.15 N/A ft2

Debris Clogging % = 50% N/A %

User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice) Calculated Parameters for Outlet Pipe w/ Flow Restriction PlateZone 3 Restrictor Not Selected Zone 3 Restrictor Not Selected

Depth to Invert of Outlet Pipe = 0.98 N/A ft (distance below basin bottom at Stage = 0 ft) Outlet Orifice Area = 0.23 N/A ft2

Outlet Pipe Diameter = 12.00 N/A inches Outlet Orifice Centroid = 0.20 N/A feetRestrictor Plate Height Above Pipe Invert = 4.00 inches Half-Central Angle of Restrictor Plate on Pipe = 1.23 N/A radians

User Input: Emergency Spillway (Rectangular or Trapezoidal) Calculated Parameters for SpillwaySpillway Invert Stage= 3.96 ft (relative to basin bottom at Stage = 0 ft) Spillway Design Flow Depth= 0.33 feet

Spillway Crest Length = 20.00 feet Stage at Top of Freeboard = 5.29 feetSpillway End Slopes = 4.00 H:V Basin Area at Top of Freeboard = 0.26 acres

Freeboard above Max Water Surface = 1.00 feet

Routed Hydrograph ResultsDesign Storm Return Period = WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 YearOne-Hour Rainfall Depth (in) = 0.53 1.07 1.19 1.50 1.75 2.00 2.25 2.52 0.00

Calculated Runoff Volume (acre-ft) = 0.106 0.386 0.264 0.346 0.424 0.520 0.634 0.766 0.000OPTIONAL Override Runoff Volume (acre-ft) =

Inflow Hydrograph Volume (acre-ft) = 0.106 0.386 0.264 0.346 0.424 0.520 0.634 0.766 #N/APredevelopment Unit Peak Flow, q (cfs/acre) = 0.00 0.00 0.00 0.01 0.01 0.03 0.19 0.47 0.00

Predevelopment Peak Q (cfs) = 0.0 0.0 0.0 0.0 0.1 0.2 1.1 2.6 0.0Peak Inflow Q (cfs) = 1.8 6.5 4.5 5.8 7.1 8.7 10.6 12.8 #N/A

Peak Outflow Q (cfs) = 0.1 0.2 0.1 0.1 0.2 0.9 2.2 2.3 #N/ARatio Peak Outflow to Predevelopment Q = N/A N/A N/A 5.1 2.5 5.9 2.0 0.9 #N/A

Structure Controlling Flow = Plate Plate Plate Plate Plate Overflow Grate 1 Outlet Plate 1 Outlet Plate 1 #N/AMax Velocity through Grate 1 (fps) = N/A N/A N/A N/A N/A 0.1 0.3 0.3 #N/AMax Velocity through Grate 2 (fps) = N/A N/A N/A N/A N/A N/A N/A N/A #N/A

Time to Drain 97% of Inflow Volume (hours) = 38 67 59 65 69 71 69 68 #N/ATime to Drain 99% of Inflow Volume (hours) = 40 72 62 69 74 77 77 76 #N/A

Maximum Ponding Depth (ft) = 1.33 2.67 2.13 2.50 2.82 3.09 3.27 3.61 #N/AArea at Maximum Ponding Depth (acres) = 0.16 0.23 0.21 0.22 0.23 0.24 0.25 0.26 #N/A

Maximum Volume Stored (acre-ft) = 0.099 0.363 0.247 0.325 0.400 0.465 0.507 0.596 #N/A

Detention Basin Outlet Structure DesignUD-Detention, Version 3.07 (February 2017)

TAMLIN ROAD STORAGE YARDBASIN B


dsdtorres

Callout

Adjust the design so that the release is equal to or less than pre-development

COUNTA for Basin Tab = 1 Ao Dia WQ Plate Type Vert Orifice 1 Vert Orifice 2Count_Underdrain = 0 0.11 (diameter = 3/8 inch) 2 1 1

Count_WQPlate = 1 0.14(diameter = 7/16 inch)

Count_VertOrifice1 = 0 0.18 (diameter = 1/2 inch) Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean

Count_VertOrifice2 = 0 0.24(diameter = 9/16 inch) 4 1 5yr, <72hr 1

Count_Weir1 = 1 0.29 (diameter = 5/8 inch) >5yr, <120hr #N/A 0

Count_Weir2 = 0 0.36(diameter = 11/16 inch) Max Depth Row

Count_OutletPipe1 = 1 0.42 (diameter = 3/4 inch) WQCV 133 Watershed Constraint Check

Count_OutletPipe2 = 0 0.50(diameter = 13/16 inch) 2 Year 214 Slope 0.040

COUNTA_2 (Standard FSD Setup)= 1 0.58 (diameter = 7/8 inch) EURV 268 Shape 2.89

MaxPondDepth_Error? FALSE 0.67(diameter = 15/16 inch) 5 Year 251Hidden Parameters & Calculations 0.76 (diameter = 1 inch) 10 Year 283 Spillway Depth

0.86(diameter = 1-1/16 inches) 25 Year 310 0.33WQ Plate Flow at 100yr depth = 0.20 0.97(diameter = 1-1/8 inches) 50 Year 328

CLOG #1= 35% 1.08(diameter = 1-3/16 inches) 100 Year 362 1 Z1_Boolean

Cdw #1 = 1.15 1.20(diameter = 1-1/4 inches) 500 Year #N/A 1 Z2_Boolean

Cdo #1 = 1.07 1.32(diameter = 1-5/16 inches) Zone3_Pulldown Message 1 Z3_Boolean

Overflow Weir #1 Angle = 0.000 1.45(diameter = 1-3/8 inches) 1 Opening Message

CLOG #2= #VALUE! 1.59(diameter = 1-7/16 inches) Draintime Running

Cdw #2 = #VALUE! 1.73(diameter = 1-1/2 inches) Outlet Boolean Outlet Rank Total (1 to 4)

Cdo #2 = #VALUE! 1.88(diameter = 1-9/16 inches) Vertical Orifice 1 0 0 1

Overflow Weir #2 Angle = #VALUE! 2.03(diameter = 1-5/8 inches) Vertical Orifice 2 0 0 Boolean

Underdrain Q at 100yr depth = 0.00 2.20(diameter = 1-11/16 inches) Overflow Weir 1 1 1 0 Max Depth

VertOrifice1 Q at 100yr depth = 0.00 2.36(diameter = 1-3/4 inches) Overflow Weir 2 0 0 0 500yr Depth

VertOrifice2 Q at 100yr depth = 0.00 2.54(diameter = 1-13/16 inches) Outlet Pipe 1 1 1 0 Freeboard

EURV_draintime_user = 2.72(diameter = 1-7/8 inches) Outlet Pipe 2 0 0 1 Spillway

Count_User_Hydrographs #N/A 2.90(diameter = 1-15/16 inches) 0 Spillway Length

CountA_3 (EURV & 100yr) = 1 3.09(diameter = 2 inches) Button Visibility Boolean TRUE Time Interval

CountA_4 (100yr Only) = 1 3.29(use rectangular openings) 1 Button_Trigger

0 Underdrain

1 WQCV Plate

0 EURV-WQCV Plate

0 EURV-WQCV VertOrifice

1 Outlet 90% Qpeak0 Outlet Undetained

S-A-V-D Chart Axis Override X-axis Left Y-Axis Right Y-Axisminimum bound

maximum bound



0

2

4

6

8

10

12

14

0.1 1 10

FLO

W [

cfs]

TIME [hr]

500YR IN

500YR OUT

100YR IN

100YR OUT

50YR IN

50YR OUT

25YR IN

25YR OUT

10YR IN

10YR OUT

5YR IN

5YR OUT

2YR IN

2YR OUT

EURV IN

EURV OUT

WQCV IN

WQCV OUT

0

0.5

1

1.5

2

2.5

3

3.5

4

0.1 1 10 100

PON

DIN

G D

EPTH

[ft]

DRAIN TIME [hr]

500YR

100YR

50YR

25YR

10YR

5YR

2YR

EURV

WQCV

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50

OU

TFLO

W [c

fs]

AREA

[ft^

2], V

OLU

ME

[ft^

3]

PONDING DEPTH [ft]

User Area [ft^2]

Interpolated Area [ft^2]

Summary Area [ft^2]

Volume [ft^3]

Summary Volume [ft^3]

Outflow [cfs]

Summary Outflow [cfs]

Outflow Hydrograph Workbook Filename:

Storm Inflow Hydrographs

The user can override the calculated inflow hydrographs from this workbook with inflow hydrographs developed in a separate program.

User-Defined SOURCE WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK #N/A

Time Interval TIME WQCV [cfs] EURV [cfs] 2 Year [cfs] 5 Year [cfs] 10 Year [cfs] 25 Year [cfs] 50 Year [cfs] 100 Year [cfs] 500 Year [cfs]

4.96 min 0:00:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A

0:04:58 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A

Hydrograph 0:09:55 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A

Constant 0:14:53 0.08 0.29 0.20 0.26 0.32 0.39 0.47 0.56 #N/A

1.008 0:19:50 0.22 0.78 0.54 0.70 0.85 1.04 1.27 1.52 #N/A0:24:48 0.57 2.01 1.38 1.80 2.20 2.68 3.25 3.91 #N/A0:29:46 1.57 5.51 3.80 4.95 6.04 7.38 8.94 10.75 #N/A

0:34:43 1.82 6.50 4.47 5.83 7.13 8.73 10.61 12.80 #N/A0:39:41 1.73 6.19 4.25 5.55 6.79 8.33 10.12 12.22 #N/A


1:54:05 0.11 0.40 0.27 0.36 0.45 0.55 0.67 0.81 #N/A1:59:02 0.10 0.37 0.25 0.33 0.41 0.51 0.62 0.75 #N/A2:04:00 0.07 0.27 0.19 0.25 0.30 0.37 0.45 0.55 #N/A2:08:58 0.05 0.20 0.14 0.18 0.22 0.27 0.33 0.40 #N/A2:13:55 0.04 0.15 0.10 0.13 0.16 0.20 0.24 0.30 #N/A2:18:53 0.03 0.11 0.07 0.10 0.12 0.15 0.18 0.22 #N/A2:23:50 0.02 0.08 0.05 0.07 0.08 0.10 0.13 0.16 #N/A

2:28:48 0.01 0.05 0.04 0.05 0.06 0.07 0.09 0.11 #N/A2:33:46 0.01 0.04 0.03 0.03 0.04 0.05 0.06 0.08 #N/A2:38:43 0.01 0.02 0.02 0.02 0.03 0.03 0.04 0.05 #N/A2:43:41 0.00 0.01 0.01 0.01 0.02 0.02 0.03 0.03 #N/A2:48:38 0.00 0.01 0.00 0.01 0.01 0.01 0.01 0.02 #N/A2:53:36 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 #N/A2:58:34 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:03:31 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:08:29 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:13:26 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:18:24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:23:22 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:28:19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:33:17 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:38:14 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:43:12 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:48:10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:53:07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A3:58:05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A4:03:02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A4:08:00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A

4:12:58 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A


5:27:22 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A5:32:19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A5:37:17 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A5:42:14 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A

5:47:12 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A5:52:10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A5:57:07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 #N/A



Summary Stage-Area-Volume-Discharge RelationshipsThe user can create a summary S-A-V-D by entering the desired stage increments and the remainder of the table will populate automatically.

The user should graphically compare the summary S-A-V-D table to the full S-A-V-D table in the chart to confirm it captures all key transition points.

Stage Area Area Volume Volume TotalOutflow

[ft] [ft^2] [acres] [ft^3] [ac-ft] [cfs]

0.00 0 0.000 0 0.000 0.00

0.50 1,969 0.045 340 0.008 0.02

1.00 5,246 0.120 2,143 0.049 0.04

1.38 7,267 0.167 4,584 0.105 0.05

1.50 7,541 0.173 5,472 0.126 0.06

2.00 8,686 0.199 9,529 0.219 0.11

2.50 9,695 0.223 14,238 0.327 0.14

2.76 10,120 0.232 16,814 0.386 0.16

3.00 10,511 0.241 19,289 0.443 0.17

3.50 11,126 0.255 24,725 0.568 2.28

3.60 11,206 0.257 25,841 0.593 2.31

3.96 11,492 0.264 29,927 0.687 2.40


EURV

100-YEAR



WQCV

For best results, include thestages of all grade slopechanges (e.g. ISV and Floor)from the S-A-V table onSheet 'Basin'.

Also include the inverts of alloutlets (e.g. vertical orifice,overflow grate, and spillway,where applicable).

dsdtorres

Text Box

Please provide UD-BMP worksheet for each of the ponds.


Appendix FDrainage Maps

A Westrian Company

TAMLIN ROAD STORAGE YARD

PROPOSED DRAINAGE MAP

X:\2510000.all\2513400\D

raw

ings\S

heet D

wgs\D

rainage\D

rainage M

ap.dw

g, D

rainage M

ap, 7/25/2019 1:27:07 P

M, C

S

dsdtorres

Callout

Please revise the line type of the parking stalls so that they are lighter (gray) to make the drawing more clear.

dsdtorres

Callout

The ultimate discharge of the stormwater runoff from the development must be to a suitable outfall. Please analyze the downstream swale/ditch. Is it adequate for the concentrated discharge of the pond? Is any protection/improvements required?

dsdtorres

Callout

Provide a legend for the basin call-outs information

dsdtorres

Text Box

Please provide stormwater flow arrows.

dsdtorres

Callout

Please label basin B drainage swale on the map.

Drainage Report- Final_v1.pdf Markup Summary

Subject: CalloutPage Label: 6Author: dsdtorresDate: 10/17/2019 1:50:20 PMColor:

which is it? gravel or asphalt?

Callout (25)


Please indicate and analyze if the downstreamswale is adequate due to the concentrateddischarge from the pond.


Assuming the dissipater is located in the ditchalong tamlin road, Please analyze if the ditch isadequate and has the capacity for this concentratedischarge from the pond.


The ultimate discharge of the stormwater runofffrom the development must be to a suitable outfall.Please analyze the downstream swale/ditch. Is itadequate for the concentrated discharge of thepond? Is any protection/improvements required?


?


Please revise this paragraph regarding the offsiteflows entering the site. It appears that you arestating that offsite flow will enter the site butbypass the ponds yet the last sentence indicatesthat offsite flow will not enter the site. If offsite flowis entering the site from where is this flow comingfrom and how will it bypass the ponds.


Per ECM I.7.1.C.1 up to 20%, not to exceed 1 acreof the applicable development site may be omittedfrom water quality. The cumulative landdisturbance proposed in basins A4, A5, and B3 willexceed 1 acre. Please revise your designaccordingly to comply with County criteria.


Please indicate the ponds as Full Spectrumdetention ponds.

undeveloped land. Runoff from this basin will follow historic drainage easterly off site and will not be detained in Water Quality Pond A. The podeveloped (0.09 acres) will not significantly increase the runoff from thiscondition.

Basin A5 consists of approximately 0.59 acres of landscape area and undevthis basin will follow historic patterns and sheet flow easterly offsite andWater Quality Pond A.

Basin B1 consists of approximately 4.30 acres of gravel drives, parking staRunoff from this basin is collected in a gravel pan located along the basasphalt pan will discharge into a grass-lined swale that conveys the runoff The cross sectional analysis of the drainage swale is presented in Appendix

Basin B2 consists of approximately 1.31 acres of gravel drives, parking staRunoff from this basin sheet flows into Water Quality Pond B.

Basin B3 consists of approximately 0.90 acres of landscaped areas and u

which is it? gravel orasphalt?

eceiving waters. Site specific temporary source control BMPs that will be implemented include, butare not limited to, silt fencing placed around downstream areas of disturbance, construction vehicleracking pads at the entrances, designated vehicle fueling areas, covered storage areas, spill

containment and control, etc. The permanent erosion control BMP’s include asphalt drives andparking, storm inlets and storm pipe.

WATER QUALITYDeveloped area within Basin A will be conveyed to Full Spectrum Water Quality and DetentionPond A, located along the site’s eastern boundary. Developed area within Basin B will be conveyedo Full Spectrum Water Quality and Detention Pond B, located in the site’s southwest corner along

Tamlin Road. It should be noted that all proposed parking and drive aisles will be constructed ofgravel. However, there is a possibility of the owner paving the drive aisles and parking stalls withasphalt in the future. Therefore, all water quality and detention calculations are per the asphaltcondition.

Pond A has a total of 7.91 tributary acres for total detention basin volume of 1.055 ac-ft. Pond Autilizes a full spectrum outlet structure to detain the WQCV for a 40-hr period, the EURV for a 72-hour period and the 100-yr volume for 73-hr period. The outlet structure will release at less thanhistoric rates. Pond A will discharge into an energy dissipater located along the eastern property line.From here, discharge will maintain the sub-basins existing drainage patterns and discharge to vacantand to the east.

Pond B has a total of 5.61 tributary acres producing a total detention basin volume of 0.592 ac-ft.Pond B utilizes a full spectrum outlet structure to detain the WQCV for a 40-hr period, the EURV for

Please indicate and analyze if the downstreamswale is adequate due to the concentrateddischarge from the pond.

historic rates. Pond A will discharge into an energy dissipater located aloFrom here, discharge will maintain the sub-basins existing drainage patteland to the east.

Pond B has a total of 5.61 tributary acres producing a total detention bPond B utilizes a full spectrum outlet structure to detain the WQCV for a a 72-hour period and the 100-yr volume for 72-hr period. The outlet struchistoric rates. Pond B will discharge directly into an energy dissipater l

Assuming the dissipater is located in the ditchalong tamlin road, Please analyze if the ditch isadequate and has the capacity for this concentratedischarge from the pond.

The ultimate discharge of the stormwaterrunoff from the development must be toa suitable outfall. Please analyze thedownstream swale/ditch. Is it adequatefor the concentrated discharge of thepond? Is any protection/improvementsrequired?

oped land. Runoffmlin Road. Runoff

water quality and Drainage Design

?

asphalt pan will discharge into a grass-lined swale that conveys the runoff to Water Quality Pond B.The cross sectional analysis of the drainage swale is presented in Appendix D.



Any offsite flows entering the site will bypass the site and not be captured in the water quality anddetention ponds. However, little to no off-site runoff is anticipated to enter the site. Drainage DesignCriteria Please revise this paragraph regarding the offsite flows entering the site. It

appears that you are stating that offsite flow will enter the site but bypass theponds yet the last sentence indicates that offsite flow will not enter the site. Ifoffsite flow is entering the site from where is this flow coming from and howwill it bypass the ponds.

owner paving the drive aisles and parking stalls with asphalt in the future. Therefore, all calculations(hydrologic and hydraulic) have been performed per the future asphalt condition. The proposed basindelineation is as follows:

Basin A1 consists of approximately 6.04 acres of gravel drives, parking stalls and landscaped areas.Runoff from these areas will sheet flow east towards Water Quality Pond A.



Basin A4 consists of approximately 1.48 aces of gravel drives, parking stalls, landscaped areas andundeveloped land. Runoff from this basin will follow historic drainage patterns and sheet floweasterly off site and will not be detained in Water Quality Pond A. The portion of this basin that isdeveloped (0.09 acres) will not significantly increase the runoff from this basin in its undevelopedcondition.

Basin A5 consists of approximately 0.59 acres of landscape area and undeveloped land. Runoff from

Per ECM I.7.1.C.1 up to 20%, not to exceed 1 acre of the applicable development site may beomitted from water quality. The cumulative land disturbance proposed in basins A4, A5, andB3 will exceed 1 acre. Please revise your design accordingly to comply with County criteria.

alls with asphalt in the future. Therefore, all calculationsmed per the future asphalt condition. The proposed basin

es of gravel drives, parking stalls and landscaped areas.owards Water Quality Pond A.

es of gravel drives, parking stalls and landscaped areas.ss-lined swale and conveyed to Water Quality Pond A.wale is presented in Appendix D.

es of gravel drives, parking stalls and landscaped areas.

Please indicate the ponds as FullSpectrum detention ponds.


gravel


Please revise step 3 as no drainage fees are dueas this is a site development plan application. Thisshould be relative to the project site.


As designed, pond B drains in 76 hrs per thesubmitted calculation.


Please indicate what conveys this flow across thetamlin road/marksheffel intersection to theeastview estates land


bridge


Adjust the design so that the release is equal to orless than pre-development


Adjust the design so that the release is equal to orless than pre-development


Provide an existing drainage plan showingappropriate basins and design points(Q) of thehistoric drainage flow patterns.


Provide a legend for the basin call-outs information

Road Storage Facility development consists paved dris interspersed within the development which helps disconumes. The IRF worksheet can be found in Appendix C.

treatment for this site is provided in two onsite full spect

gravel

Step 1: The Tamlin Road Storage Facility development consists paved drive aisles and parkingspaces with lawn areas interspersed within the development which helps disconnect impervious areasand reduce runoff volumes. The IRF worksheet can be found in Appendix C.

Step 2: Water Quality treatment for this site is provided in two onsite full spectrum water quality anddetention ponds. Runoff from the site will be collected in vegetated swales and conveyed to thedetention ponds.

Step 3: Drainage fees will be paid with the platting of the site in order to help fund major drainageimprovements per the “Sand Creek Drainage Basin Planning Study”. These improvements helpstabilize the drainage way.

Step 4: BMP’s will be utilized to minimize off-site contaminants and to protect the downstreamreceiving waters. Site specific temporary source control BMPs that will be implemented include, butare not limited to, silt fencing placed around downstream areas of disturbance, construction vehicletracking pads at the entrances, designated vehicle fueling areas, covered storage areas, spillcontainment and control, etc. The permanent erosion control BMP’s include asphalt drives andparking, storm inlets and storm pipe.

WATER QUALITYDeveloped area within Basin A will be conveyed to Full Spectrum Water Quality and DetentionPond A, located along the site’s eastern boundary. Developed area within Basin B will be conveyedto Full Spectrum Water Quality and Detention Pond B, located in the site’s southwest corner along

Please revise step 3 as no drainage fees are due as thisis a site development plan application. This should berelative to the project site.

ary acres for total detention basin volume of 1.055 ac-ft. Pond Ature to detain the WQCV for a 40-hr period, the EURV for a 72-

me for 73-hr period. The outlet structure will release at less thange into an energy dissipater located along the eastern property line.n the sub-basins existing drainage patterns and discharge to vacant

ry acres producing a total detention basin volume of 0.592 ac-ft.let structure to detain the WQCV for a 40-hr period, the EURV forlume for 72-hr period. The outlet structure will release at less thange directly into an energy dissipater located along Tamlin Road.

As designed, pond B drains in 76hrs per the submitted calculation.

ischarge will maintain the sub-basins existing drainage patterns and discharge west Road towards Eastview Estates Filing No. 3.

CONTROL PLANCounty Drainage Criteria Manual specifies an Erosion Control Plan and associated costubmitted with the Final Drainage Report. We respectfully request that the Erosionand Cost Estimate be submitted in conjunction with the grading and erosion controltruction assurances posted prior to obtaining a grading permit.

N & MAINTENANCEnsure the function and effectiveness of the stormwater infrastructure, maintenance

h as inspection, routine maintenance, restorative maintenance, rehabilitation and repair,The property owner shall be responsible for the inspection, maintenance, rehabilitationstormwater and erosion control facilities located on the property unless another party responsibility in writing and responsibility is properly assigned through legal

Please indicate what conveys this flow across the tamlinroad/marksheffel intersection to the eastview estates land

taken into consideration pond

in Fees

BridgeImperviousAcre

Total Fee -Drainageand Pond

$5,559 $220,246.01

bridge

0.264 0.346 0.424 0.520 0.634 0.766 0.000

0.264 0.346 0.424 0.520 0.634 0.766 #N/A0.00 0.01 0.01 0.03 0.19 0.47 0.000.0 0.0 0.1 0.2 1.1 2.6 0.04.5 5.8 7.1 8.7 10.6 12.8 #N/A0.1 0.1 0.2 0.9 2.2 2.3 #N/AN/A 5.1 2.5 5.9 2.0 0.9 #N/APlate Plate Plate Overflow Grate 1 Outlet Plate 1 Outlet Plate 1 #N/AN/A N/A N/A 0.1 0.3 0.3 #N/AN/A N/A N/A N/A N/A N/A #N/A59 65 69 71 69 68 #N/A62 69 74 77 77 76 #N/A

2.13 2.50 2.82 3.09 3.27 3.61 #N/A0.21 0.22 0.23 0.24 0.25 0.26 #N/A

0.247 0.325 0.400 0.465 0.507 0.596 #N/A

Adjust the design so that the release isequal to or less than pre-development

0.499 0.650 0.788 0.944 1.108 1.300 0.00

0.499 0.650 0.788 0.944 1.108 1.301 #N/0.00 0.01 0.02 0.04 0.30 0.73 0.00.0 0.1 0.1 0.3 2.4 5.7 0.0

11.6 15.0 18.2 21.7 25.5 29.8 #N/0.2 0.3 0.7 3.5 5.3 5.5 #N/N/A 4.2 4.9 10.5 2.2 0.9 #N/Plate Plate Overflow Grate 1 Overflow Grate 1 Outlet Plate 1 Outlet Plate 1 #N/N/A N/A 0.1 0.5 0.8 0.8 #N/N/A N/A N/A N/A N/A N/A #N/59 64 68 67 65 64 #N/63 70 74 74 73 73 #N/

3.95 4.45 4.83 5.02 5.22 5.55 #N/0.27 0.31 0.34 0.35 0.37 0.39 #N/

0.475 0.619 0.745 0.808 0.880 1.008 #N/

Adjust the design so that the release isequal to or less than pre-development

iated with semi-arid climates. The headwaters of the basin are in Thetopography trends south to southwesterly towards its ultimate outfall intond Creek DBPS, the Sand Creek East Fork Subtributary runs outside thee. This drainageway begins at the confluence with the mainstem of East

north to Barnes Road.

M Map number 08041C0543G and 08041C0545G, the site does not falloodplain and is classified as Zone X, which are areas determined to beance floodplain. FIRM maps of the site and surrounding areas have been

DRAINAGEare split on the site by a ridge running north-south. The eastern portion ofeloped land to Sand Creek East Fork Subtributary. The western portion ofin Road and Marksheffel road into Eastview Estates Filing No. 3 storm

NAGE CONDITIONS

Provide an existing drainage plan showingappropriate basins and design points(Q) ofthe historic drainage flow patterns.

Provide a legend forthe basin call-outsinformation


Please revise the line type of the parking stalls sothat they are lighter (gray) to make the drawingmore clear.


Please label basin B drainage swale on the map.


Provide protection for this grass swale as thevelocity is exceeding the permissible velocity


update accordingly per comments on compositeimpervious calculation


update accordingly per comments on compositeimpervious calculation

Subject: CalloutPage Label: 18Author: CSDate: 7/10/2019 1:37:18 PMColor:

SITE


SITE


SITE

Subject: HighlightPage Label: 6Author: dsdtorresDate: 10/17/2019 1:48:44 PMColor:

asphalt

Highlight (12)

Please revise the line type of theparking stalls so that they arelighter (gray) to make the drawingmore clear.

Please label basin Bdrainage swale on themap.

Q (cfs) = 22.50Area (sqft) = 4.88Velocity (ft/s) = 4.61Wetted Perim (ft) = 14.84Crit Depth, Yc (ft) = 0.62Top Width (ft) = 14.76EGL (ft) = 0.85

Depth (ft)Section

Provide protection forthis grass swale asthe velocity isexceeding thepermissible velocity

Project:

Basin ID:


Required Volume Calculation 6716.7 Top of Micropool -- 0.00 -- -- --

Selected BMP Type = EDB 6717 -- 0.30 -- -- --

Watershed Area = 7.91 acres 6718 -- 1.30 -- -- --

Watershed Length = 600 ft 6719 -- 2.30 -- -- --

Watershed Slope = 0.050 ft/ft 6720 -- 3.30 -- -- --

Watershed Imperviousness = 71.70% percent 6721 -- 4.30 -- -- -- 1

Percentage Hydrologic Soil Group A = 100.0% percent 6722 -- 5.30 -- -- -- 1

Percentage Hydrologic Soil Group B = 0.0% percent 6722.5 -- 5.80 -- -- -- 1

Percentage Hydrologic Soil Groups C/D = 0.0% percent 6723.7 -- -- -- --




OO

ArLength

(ft)


Stage(ft)


Area(ft 2̂)

Width(ft)


BASIN A



update accordinglyper comments oncomposite imperviouscalculation

Project:

Basin ID:


uired Volume Calculation 6711.74 Top of Micropool -- 0.00 -- -- -- 0 0.000

Selected BMP Type = EDB 6712 -- 0.26 -- -- -- 462 0.011

Watershed Area = 5.61 acres 6713 -- 1.26 -- -- -- 7,015 0.161

Watershed Length = 840 ft 6714 -- 2.26 -- -- -- 9,304 0.214

Watershed Slope = 0.050 ft/ft 6715 -- 3.26 -- -- -- 10,935 0.251

Watershed Imperviousness = 57.40% percent 6715.6 -- 3.96 -- -- -- 11,492 0.264

Percentage Hydrologic Soil Group A = 100.0% percent -- -- -- --

Percentage Hydrologic Soil Group B = 0.0% percent -- -- -- --

Percentage Hydrologic Soil Groups C/D = 0.0% percent -- -- -- --





OptionalOverride

Area (ft 2̂)Length

(ft)


Stage(ft)


Area(ft 2̂)

Width(ft)


BASIN B


Area(acre)


update accordingly percomments on compositeimpervious calculation

SITE

SITE

SITE

Runoff fromasphalt panThe cross se


gravel


Drainage DesignCriteria


Water Quality


Water Quality


Water Quality Pond


Water Quality


Water Quality


Water Quality


Water Quality

30 acres of gran a gravel pan-lined swale th

Basin B1 consists of approximately 4.30 acres of gravel drives, parking stalls, and landscaped areas.Runoff from this basin is collected in a gravel pan located along the basin’s western border. Theasphalt pan will discharge into a grass-lined swale that conveys the runoff to Water Quality Pond B.The cross sectional analysis of the drainage swale is presented in Appendix D.



Any offsite flows entering the site will bypass the site and not be captured in the water quality anddetention ponds. However, little to no off-site runoff is anticipated to enter the site. Drainage DesignCriteria

of gravel drives, parkingards Water Quality Pond

of gravel drives, parking

d A.

g stalls and landscaped ared to Water Quality Pond

dix D.

ndix D.

g stalls and landscaped areas.ed to Water Quality Pond A.

ndix D.

g stalls, landscaped areas and

48 aces of gravel drives,basin will follow histord in Water Quality Pond

cantly increase the runof

stalls, and landscaped arbasin’s western border. ff to Water Quality Pondix D.

Basin A5 consists othis basin will folloWater Quality Pond

Basin B1 consists o

y 1.31 acres of gravel d into Water Quality Pond

ly 0.90 acres of landsca


Water Quality


Pond

Subject: PolygonPage Label: 18Author: CSDate: 7/10/2019 1:37:30 PMColor:

Polygon (3)



Subject: Text BoxPage Label: 1Author: dsdtorresDate: 10/15/2019 3:28:12 PMColor:


Text Box (4)


Please provide UD-BMP worksheet for each of theponds.


Per the submitted landscape plan the majority ofthe landscape islands have rock as a surfacematerial yet it does not appear to have beenaccounted for. For example basin B2, has a largeof amount of these islands with rock yet itattributes 1.46 acres to lawn (0% impervious) andthere is very little lawn in this basin. Please reviewthe submitted landscape plan and adjust thecalculations for all the basins accordingly.


Please provide stormwater flow arrows.

ely 0.90 acres of landscc drainage patterns and s

ed in Water Quality Pond

te will bypass the site an

Drainageand Pond

20,246.01

tional Flood Hazard Layer FIRMette77"N

C&M Properties, LLC12748 Barossa Valley Road

Colorado Springs, CO 80921

June 13, 2019Project No. 25134.01


Please provideUD-BMP worksheetfor each of theponds.

100% 0.00 0.0% 90% 0.00 0.0% 0% 0.59 0.0%

100% 2.84 66.0% 90% 0.00 0.0% 0% 1.46 0.0%

100% 0.38 29.0% 90% 0.00 0.0% 0% 0.93 0.0%

100% 0.00 0.0% 90% 0.00 0.0% 0% 0.90 0.0%

POND

POND

2513400_Drainage_Calcs_v2.07.xlsm

Per the submitted landscape plan the majority of the landscapeislands have rock as a surface material yet it does not appearto have been accounted for. For example basin B2, has a largeof amount of these islands with rock yet it attributes 1.46 acresto lawn (0% impervious) and there is very little lawn in thisbasin. Please review the submitted landscape plan and adjustthe calculations for all the basins accordingly.

Please provide stormwaterflow arrows.

Documents

FINAL DRAINAGE REPORT FOR TAMLIN ROAD RV STORAGE …€¦ · FINAL DRAINAGE REPORT FOR TAMLIN ROAD RV STORAGE Page i FINAL DRAINAGE REPORT FOR TAMLIN ROAD RV STORAGE Prepared For: