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HomeMy WebLinkAbout2012-06-19 Stormwater Report -Pondview Rev 5-10-2012 Stormwater Report "Pondview" 26 Main Street North Andover, Massachusetts January 19, 2012 Revised March 13, 2012 Revised April 17, 2012 Revised May 10, 2012 Prepared for. Jeffco, Inc. PO Box 802 Andover, MA 01810 Prepared By: Andover Consultants, Inc. 1 East River Place Methuen, MA 01844 �JAMES WRWE 7HER II �� do.34716 "' ..... f Introduction/Proiect Descri tp 10n The project proposes the construction of an eight unit condominium on a parcel of land behind 22-24 and 28-30 Main Street. The 24,776 square foot parcel off of Main Street is roughly located between Saunders Street and Sutton Street and is within the Industrial S Zoning District, as are all abutting properties, and is situated in the Downtown Overlay District. The project is submitted as a residential use in the Overlay District. The project includes the demolition of two existing wood frame garages (totaling about 2,870 square feet) and the removal of 10, 145 square feet of existing pavement as a redevelopment of the lot. Access to the parcel is via two existing curb cuts on Main Street at 22-24 and 28-30, and access and utility easements through the parcels along the side lines of each lot. The condominium structure will consist of 4 levels; a lower level with garage, a first floor for living space and a second floor with two bedrooms and a third floor with a master bedroom. The project will include a 22-foot wide access drive way and an individual driveway for one car parking, in addition to the garaged parking space noted above. The project will connect to existing water and sewer mains in Main Street through the existing access/utility easements. The parcel also abuts Sutton Pond along its easterly boundary and a former Boston and Maine railroad corridor along its northerly boundary. The railroad corridor is no longer in use, having long since been abandoned. Remnants of the railroad bridge crossing Sutton Pond are still visible in the pond as is a remnant of an associated timber wall near the northeast corner of the parcel. The parcel is more than 200-feet from the inlet and outlet of Sutton Pond so there are no riverfront areas on the lot. There is, however, a vegetated wetland bordering Sutton Pond easterly of the lot and was flagged Greg Hocmuth in August of 2011. All work on the lot falls outside of the 25-foot "no disturbance zone". The condominium structure is located just outside of the 50-foot "no build zone", while other components of the work fall within the 100-foot Buffer Zone of the bordering vegetated wetland. Erosion control will consist of staked hay bales along the easterly and northerly limits of the work. The project will remove more impervious cover than it will create so there is no loss of recharge of groundwater as a result of the work. The project will, however, include installation of a precast concrete galley system to recharge the required volume. Water quality treatment for runoff from the proposed driveway will also be provided by the precast concrete galley system. Existing site features consist of the existing garages and paved areas. The back portion of the lot, on the slope down to Sutton Pond, consists of a few trees and shrubs and was modeled as "good" woods. The area between the tree line and the existing pavement consists of a mixture of bare soil and weed, sapling cover complex. A composite CN of 65 (average of fair to good grass cover) was assumed for this cover type. Soils on the site were mapped by the NRCS as Canton fine sandy loams (map unit designations 420B and 420C as obtained from the USDA Web Soil Survey website). The Canton soil is assigned to Hydrologic Soil Group (HSG) B. Surface runoff from the parcel and adjacent parcels onto the lot generally flows easterly towards Sutton Pond. r DEP Stormwater Management Standards The project is an eight unit residential condominium project not tributary to a critical area so is subject to the Massachusetts Stormwater Standards to the maximum extent practicable. In addition, the project will remove existing pavement and existing, wood frame garages resulting in a net decrease in impervious surface areas once the project is complete. As such, the project is also a redevelopment of an existing developed site. The new work will meet the local requirement of maintaining a 25-foot no disturbance zone from the bordering wetland of Sutton Pond. Standard #1 No New Untreated Discharges Runoff from the proposed paved driveways discharges to a deep sump, hooded catch basin then a precast concrete infiltration system which then discharges to a depression and level spreader to dissipate outlet velocity. Standard #2 Peak Rate Attenuation Runoff from the project discharges in a general easterly direction towards Sutton Pond. As noted above, the work will result in a net decrease in impervious surfaces, peak rates of runoff to Sutton Pond from the parcel and tributary off parcel areas have been calculated. Peak rates of runoff for the 1, 2, 10, and 100-year storm events are as follows: 1-year storm 2-year storm 10-year storm 100-year storm Pre= 1.4 cfs pre= 1.9 cfs pre = 3.4 cfs pre= 6.1 cfs Post= 1.2 cfs post= 1.7 cfs post=3.1 cfs post=5.7 cfs (was 1.l cfs) (was 1.6 cfs) (was=3.0 cfs) (was 5.6 cfs) As can be seen, the peak rates of runoff, post construction, are less than the pre construction rates due to the decrease in impervious areas and the conversion of the bare soil/weedy surface cover to lawn. Standard #3 Recharize The soils at the site according to the USDA Web Soil Survey consist of Canton fine sandy loam. Canton soils are HSG B soil. The target depth to recharge is 0.35 inches. Infiltration/Recharge Calculations Total, existing impervious area = 13,015 sf Total proposed, new impervious area = 10,545 sf+ 650 sf= 11,195 sf Net new impervious area = -1,820 sf There is a decrease in impervious area resulting in no net loss of recharge post construction. However, the proposed precast concrete galley system will provide recharge as detailed below. Precast concrete Ralley infiltration system: Volume required = 11,195 sf x 0.35"/ 12" per foot = 326.5± cf(2445 gallons) Provide 2 - 8 x 14 precast concrete galleys 4'-8" high Volume provided below invert = 2 x 7 ft x 13 ft x 2.36 ft =429.5 cf 429.5 cf> 326.5 cf, ok Note: rear half of the roof(2,148 sf) will discharge to the grass area behind the structure. Time to drain (static method Total volume = vol. =430cf Bottom area = A =7 ft x 13 ft x 2= 182 sf k (HSG B soil =0.52 in/hr (0.0433 ft/hr) t = vol/(k * A), t=430/(0.0433*182) = 54.5 hrs < 72 hrs, ok r Standard #4 Water__Quality Water Quality Calculations The infiltration system will provide the 80% TSS removal with pretreatment provided by a deep sump hooded catch basin. Calculate the water quality volume: Tributary area(new) = 11, 195- (2,148 (roof)) = 9,047 sf Required WQV: Use 0.5" depth for WQV calculation. WQV =0.5/12 ft x 9, 047 = 377±cf Provided WQV =429.5 cf> 377 cf, ok INSTRUCTIONS: version 1,Auromaled:Mar.4,2008 1.In BMP Column,click on Blue Cell to Activate Drop Down Menu 2.Select BMP from Drop Down Menu 3.After BMP is selected,TSS Removal and other Columns are automatically completed. Location:126 Main St North Andover,MA B C D E F TSS Removal Starting TSS Amount Remaining BMP' Rate' Load* Removed C*D Load D-E d Deep Sump and Hooded = Catch Basin 0.25 1.00 0.25 0,75 W Subsurface InfIltratlon O O Structure 0.80 0.75 0.50 0.15 d C Q 0.00 0.15 0.00 0.15 000 0.15 0.00 0.15 lti V 0.001 0.15 0.00 0.15 Separate Form Needs to be Completed for Each Total TSS Removal = 85'�o Outlet or BMP Train Project: °°^°"°' Prepared By: fsf 'Equals remaining load from previous BMP(E) Date: 4/17/2012 which enters the BMP Standard #5 Land Uses With Higher Potential Pollutant Loads (LUHPPLs) The site is not a land use with higher potential pollutant loads. Standard #6 CriticaI Areas The project will not create any discharges to Critical Areas. Standard #7 Redevelopment Project There will be a reduction in impervious areas by the proposed construction in an area previously developed and qualifies as a redevelopment project. Standard #S Construction Period Pollution Prevention and Erosion and Sedimentation Control A Construction Period Pollution Prevention and Erosion and Sedimentation Control plan has been prepared and will be implemented to protect the adjacent properties from sedimentation during construction. The project is not covered by a NPDES Construction General Permit due to the small scale of the project. Standard #9 Operation and Maintenance Plan An Operation and Maintenance Plan (O&M Plan) has been developed which lists the condominium association as the responsible party. The O&M Plan details the schedule for routine maintenance and inspection. Standard #10 Prohibition of Illicit Discharges All illicit discharges at the site will be prohibited. An Illicit Discharge Compliance Statement will be submitted prior to the start of any land disturbance activities. Operation and Maintenance Plan 26 Main Street North Andover, Massachusetts 1. The piped drainage system, including the catch basin sediment sump, precast concrete galley system, drain manhole and the outlet flared end section with level spreader shall be owned and operated by the Condominium Association. At the time of this writing, the association has not been created so its identity is not yet known but shall be referred to as the "Association". 2. The Association or its designated agent shall inspect the stormwater management system 4 times per year, including visual inspection of catch basin sediment sump, drain manhole, precast galley system and terminal level spreader. The owner shall ensure that no portion of the stormwater management system is damaged, blocked or otherwise in a state that prevents its proper operation. 3. The Association shall ensure that accumulated silt and debris within the catch basin is removed in a timely manner. The catch basin shall be cleaned when the sediment level is within the two feet of the outlet pipe. The basin shall be cleaned at least annually in the spring following winter sanding. 4. The Association shall inspect the drainage system components noted above after every major storm for the first year and then every three months thereafter. 5. The association shall inspect the precast galley system after storms of 2 inches or more. The system shall drain within 72 hours after the end of the storm. In the event that the system is not draining, pump filtered water into the drain manhole and remove any debris which is clogging the system. 6. The level spreader shall be mowed, typically when other lawn areas are mowed. Do not aerate the soil in the level spreader area. 7. Illicit discharges are to be prohibited. The Association shall report any illicit discharges once discovered to the North Andover Police and Health Departments. 8. The Association should have the parking area swept of sand and debris after the winter sanding season. Construction Period Pollution Prevention and Erosion and Sedimentation Control Narrative Erosion control measures will be implemented prior to the start of construction. A staked hay bale and silt fence barrier will be installed as shown on the Site Plan. When Construction is complete and all disturbed areas have been stabilized, a certificate of compliance shall be sought from the North Andover Conservation Commission. General Construction Period Operation and Maintenance Plan During construction, the maintenance program shall consist of the following: 1. The erosion control barrier shall be visually inspected daily and shall be repaired or replaced as necessary. 2. Sediment will be removed from the barriers when it has accumulated to a depth of six inches. 3. All seeded or otherwise stabilized areas shall be inspected periodically to insure proper germination and adequate coverage and shall be reseeded/restabilized as necessary. 4. Temporary sediment control structures or devices shall be inspected daily and prior to forecast rainfall of 2 inches or more. Responsible Party The property Owner shall be responsible for ensuring that the site development contractor hired for the work is continually in compliance with this Plan. Construction Period Pollution Prevention Measures The erosion control barrier shall be constructed prior to the start of construction. All disturbed areas shall be mulched and seeded or otherwise permanently stabilized immediately upon reaching finish grade. Site Development Platt See Site Plans revision dated April 19, 2012, and prepared by Andover Consultants, Inc. for development details. Construction Sequencing Platt Major activities will generally proceed as follows: 1. Install perimeter erosion control barrier(staked hay bales and silt fence). 2. Demolish existing structures and existing pavement and remove off site in accordance with all local, state and federal laws and regulations. 3. Clear and grub areas within the limit of work (inside erosion barrier). 4. Prepare building site for construction. S. Construct subsurface utilities connecting to public utilities in Main St. including water, sewer, electric and gas. 6. Install parking lot drainage system including level spreader. 7. Prepare sub-grade and install base material for parking areas to grade. 8. Install binder course of pavement for parking lot. 9. Final grade, seed and mulch disturbed non-paved areas. 10. Complete building construction, 11. Install finish course of pavement. 12. Clean project area 13. Once site is stabilized obtain a certificate of compliance from the Conservation Commission and remove perimeter erosion control stakes and properly dispose of in accordance with applicable laws and regulations. Sequencing of Erasion and Sediinientation Controls Erosion and sedimentation controls will be installed prior to any disturbance at the site. An ongoing inspection and maintenance schedule will be followed and additional measures will be added as necessary. Inspection Schedide During construction the inspection schedule shall consist of the following: 1. The erosion barrier shall be visually inspected daily and shall be repaired or replaced as necessary. 2. All seeded areas shall be inspected periodically to insure proper germination and adequate coverage and shall be reseeded as necessary. Any wash outs shall be promptly repaired, reseeded and mulched 3. Maintain existing driveway by sweeping as needed to prevent tracking of soil onto existing parking lot, remove any soil tracked onto existing pavement. Inspection and Maintenance Log Fonn Inspection and Maintenance Report 25 Maim Street North Andover, Massachusetts DEP File No. 242-1544 Catch basin Condition Action Taken Infiltration galleys Pipe flare end Level spreader Drain manhole Signed Date Lon_g Term Pollution Prevention Plan Good housekeeping practices The Condominium Association (Association) shall ensure regular maintenance activities at the site remain on schedule. Professional Landscape and Building Maintenance services may be utilized to maintain the building and grounds. Provisions for storing materials and waste products inside or under cover No Hazardous materials shall be stored at this site. Vehicle washing controls No vehicle washing activities will take place in the area. Requirements for routine inspections and maintenance of stormwater BMPs The Association will be responsible for ensuring that the inspection and maintenance activities including regular inspection and maintenance of the storm water management structures continue indefinitely. Requirements for storage and use of fertilizers, herbicides, and pesticides No fertilizers, herbicides or pesticides shall be stored outside. These materials shall be stored in compliance with the manufacturer's recommendations and in compliance with all local, state and federal rules and regulations. Provisions for solid waste management Any solid waste produced by the site will be temporarily stored in trash receptacles and emptied weekly. Snow disposal and plowing Snow shall not be plowed directly into the street but stored just off the edge of pavement. Plow damage to grassed areas adjacent to the pavement shall be repaired in the spring once growing season starts. Winter Road Salt and/or Sand Use and Storage restrictions No salt shall be stored outside at the site. Minimal use of salt and sand is encouraged to mitigate slippery conditions. Street sweeping schedules The paved parking area shall be swept in the spring (April or May). Provisions for prevention of illicit discharges to the stormwater management system The storage and use of hazardous materials is prohibited. No illicit discharges of oil or other hazardous materials shall occur at the site. Any detected illicit discharges shall be reported immediately to the North Andover Police and Board of Health. List of Emergency Contacts for implementing Long-Term Pollution Prevention Plan Condominium Association North Andover Police Department 978-683-3168 North Andover Conservation Department 978-688-9530 North Andover• Health Department 978-688-9540 Massachusetts Department of Environmental Protection 978-694-3200 Illicit Discharge Statement 26 Main Street North Andover, MA 01845 As the Owner of the project depicted on design plans for Assessor Map 28 Parcel 14, aka Parcel III rear of 22-24 Main St., in the Town of North Andover, Massachusetts, I hereby certify that no illicit discharges are proposed or exist on the site, Print Name Signature Date USGS Site Locus i.lA%6RENL`�s�f y!r t WCtpgLP T" - '•t� �•' " yak t\ )1 %/ �• � HM f A:-, % f, :t_r t / {{� si i�•ij �. S y� ��, �ti� SITE 4-1 nned *� tt 1,•. 5. ,c r f 1 � t :.> ,. — �`.�--,� y \� t ; • -►i, .- � \ cif��`� �� � `�91111C1F[�) �•'��'� ��� •.tk. 4 . 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'r •t � �`„ � z � �•-t G"✓� 5� ay 75, 5 e s Rocky Brook r- }Jr. ..54 IF, MQSgufto Brook] _ r I r i. j� r LtM1TOF RIVERViEW -Ile STREET WAYm ZONE COCHICHEWICK APPROXIMATE SCALE :> C x lJRC1011a�0 FEET 1 9��� SU- -roN �` STREET 5 ys� ° c, o �` ~u -Sutton Q n ® NATIONAL FLOOD INSURANCE PROGRAM A I N Pond -p fi -� STREET _.. Dam 4 I w STREET • N O w I 1RM `A 13 CE FLOOD INSURANCE RATE MAP ZONE X J1 7- ZONE X m () U' [n d TOWN OF NORTH ANDOVE,R, � MASSACHUSETTS ESSEX COUNTIF ABANDONED RAILROAD o 2 0 BRIDGE PANEL 3OF15 ¢ OMFF MAP INCEX FOR PANES NOT PAINTED) S UTTON, Osgood = j POND ''` � Dam y PANEL ltYAr7pr1 P.0 C ESCOMRUNITY-PANEL NUMBER O I 250098 0003 C MAP REMISED: _O "',a JUNE 2. 1993 Ljj SE Et1 7 FadeW EmaTelaW 31anagernentAgmJ �T C This m an official copy of a portion of the above refecanced flood map. It �(- �� ,1�o LIMIT OF was extracted using F-MrrOn-Lone. This map does not ro4act changes FLOODWAY or amendments which may have boon made subsDqucrtt to tho date on the tltlo dock. For the latest product information about National Rood Insurance Program eaad mope check the FEMA Flood Map Store at wow.mso.fema-g'W .............. . .............. __.. ____ ____ ____. Test Pit Data SOIL TEST PIT LOG Deep Observation Hole Number: TP_1 round elevation: 56.1 Coarse Fragments Soil Horizon/Soil Matrix:Color- Soil Texture %by volume Soil Soil Depth(in.) sayer Moist(Munsell) (USDA) Structure Consistence Other Depth for Percent rave[ Cobbles& (Moist) Stones 0-120 Fill n/a Soil Evaluator James Fairweather#702 Date of test Jan. 3, 2012 Additional Notes: No observed water, some cobbles and small boulders near bottom. Possible fill associated with old railroad bridge abutment. Top 4 feet± evidence of old trash disposal area with several glass bottles and layers of ash. Bottom of pit=46.1. ............................................... SOIL TEST PIT LOG Deep Observation Hole Number: -2 round elevation: 56.1 Coarse Fragments Soil Horizon/Soil Matrix:color- Soil Texture %by Volume Soil Soil Depth(in.) Layer Moist{Munsell} (USDA) Structure Consistence Other Depth Color Percent ravel Gobbles& (Moist) Stones 0-20 Fill n/a 20-30 Ab 10 YR 2/2 Sandy loam massive friable 30-44 Bw 10 YR 4/6 Loamy massive friable sand 44-116 c 2.5 y 5/4 Sand & Single loose ravel rain Soil Evaluator James Fairweather#702 Date of test Jan. 3,2012 Additional Notes: No observed water table. Few small boulders near bottom, fine-medium platy structure at 9T. Bottom of pit 46.4. ................................. ......... ... SOIL TEST PIT LOG Deep Observation Hole Number: TP-3 -- - ^round elevation 57.4 Coarse Fragments Soil Horizon/Soil Matrix:Color- Soil Texture %by Volume Soil Soil Depth(in.) Layer Moist{Mansell} (USDA) Cobbles& Structure Consistence Other Depth Color Percent ravel (Moist) Stones 0-16 Fill n/a 16-20 Ab 10 YR 2/2 Sandy loam massive friable 20-26 Bw1 10 YR 4/6 Loamy massive friable sand 26-34 Bw2 10 YR 5/6 Loamy massive friable Sand 44-116 c 2.5 y 5/4 Sand & Single loose ravel rain Soil Evaluator James Fairweather#702 Date of test Jan. 3,2012 Additional Notes: No observed water. Fine to medium platy structure at 86". Bottom of pit 48.7 ............................................................. . ... .. HydroCAD Calculations �X 1 Existing DEV 2 DEV 9 Developed 2 Developed I ca 0 0 CB DRYWELL DMH Level Spreader summary Bobcat Reach Pon .Ink Drainage Diagram for Jeffco-Main St 05-10-12 Prepared by Andover Consultants, Inc. HydroCAD®6.00 s/n 002099 0 2006 HydroCAD Software Solutions LLC HydroCAD Pre-developed calculations 1-Year Storm P=2.6 inches Jeffco-Main St 05-10-12 Type 111 24-hr 1-Yr Rainfall=2.60" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 OO 2006 H droCAD Software Solutions LLC Subcatchment EX 1: Existing Runoff - 1.4 cfs @ .12.05 hrs, Volume= 0.091 af, Depth= 1.13" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 1-Yr Rainfall=2.60" Area sf CN Description 24,161 98 Paved parking & roofs 6,114 61 >75%Grass cover, Good, HSG B 7,536 65 bare soil/weeds/grass, HSG B 4 014 55 Woods Good HSG B 41,825 83 Weighted Average 17,664 Pervious Area 24,161 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.5 50 0.0380 1.55 Sheet Flow, Smooth surfaces n=0.011 P2= 3.20" 0.2 50 0.0400 4.06 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.7 84 0.0160 2.04 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.8 76 0.0100 1.61 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.2 44 0.0450 3.42 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 38 0.2400 7.89 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.5 342 Total Jeffco-Main St 05-10-12 Type 11124-hr 1-Yr Rainfa11=2.60" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 ©2006 H droCAD Software Solutions LLC Subcatchment EX 1: Existing Hydrograph 1.4 cis —Runo11 Type III 24-hr 1-Yr Rainfall=2.60" 1 Runoff Area=41 ,825 sf y Runoff Volume=0.091 of Runoff Depth=1 .13" Flow Length=342' Tc=2.5 m i n CN=83 0 0 1 2 77 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 2-Year Storm P=3.1 inches Jeffco-Main St 05-10-12 Type I1124-hr2-Yr Rainfall=3.10" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 ©2006 H droCAD Software Solutions LLC Subcatchment EX 1: Existing Runoff = 1.9 cfs @ 12.05 hrs, Volume= 0.122 af, Depth= 1.53" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2-Yr Rainfall=3.10" Area sf CN Description 24,161 98 Paved parking & roofs 6,114 61 >75% Grass cover, Good, HSG B 7,536 65 bare soil/weeds/grass, HSG B 4,014 55 Woods Good HSG B 41,825 83 Weighted Average 17,664 Pervious Area 24,161 Impervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 0.5 50 0.0380 1.55 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.20" 0.2 50 0.0400 4.06 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.7 84 0.0160 2.04 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.8 76 0.0100 1.61 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.2 44 0.0450 3.42 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 38 0.2400 7.89 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.5 342 Total Jeffco-main St 05-10-12 Type III24-hr2-Yr Rainfall=3.io" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 ©2006 H droCAD Software Solutions LLC Subcatchment EX 1; Existing Hydrograph 2 1.9 efs —Runoff Type 111 24-hr 2-Yr Rainfall=3.10" Runoff Area=41 ,825 sf Runoff Volume=0.122 of 1 Runoff Depth=1 .53" Flow Length=342' Tc=2.5 rein CN=83 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) IQ-Year Storm P=4.5 inches Jeffco-Main St 05-10-12 Type 11124-hr 10-Yr Rainfall=4.50" Prepared by Andover Consultants, Inc. H droCAD®8.00 sin 002099 ©2006 H droCAD Software Solutions LLC Subcatchment EX 1. Existing Runoff = 3.4 cfs @ 12.04 hrs, Volume= 0.218 af, Depth= 2.73" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 10-Yr Rainfall=4.50" Area sf CN Description 24,161 98 Paved parking & roofs 6,114 61 >75%Grass cover, Good, HSG B 7,536 65 bare soil/weeds/grass, HSG B 4,014 55 Woods Good HSG B 41,825 83 Weighted Average 17,664 Pervious Area 24,161 Impervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 0.5 50 0.0380 1.55 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.20" 0.2 50 0.0400 4.06 Shallow Concentrated Flow, Paved Kv=20.3 fps 0.7 84 0.0160 2.04 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.8 76 0.0100 1.61 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.2 44 0.0450 3.42 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 38 0.2400 7.89 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.5 342 Total Jeffco-Main St 05-10-12 Type 11!24-hr 10-Yr Rainfall=4.50" Prepared by Andover Consultants, Inc. H� RAUO v _ Solutions LLC dro 8A0 sln Ofl2fl99 C�20fl6 H droCAp Software Sal,tf„ Subcatchment EX 1: Existing Hydrograph 3.4 cfs —Runoff 3 Type III 24-hr 10-Yr Rai nfal l=4.50" Runoff Area=41 ,825 sf N Runoff Volume=0.218 of 'G 2- Runoff Depth=2.73" Flow Length=342' Tc=2.5 min CN=83 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 2& 27 28 29 30 Time (hours) 100-Year Storm P=7.0 inches Jeffco-Main St 05-10-12 Type/1/24-hr 100-Yr Rainfall=7.00" Prepared by Andover Consultants, Inc. H droCAD®8.00 sln 002099 ©2006 N droCAD Software Solutions LLC Subcatchment EX 1: Existing Runoff — 6.1 cfs @ 12.04 hrs, Volume= 0.402 af, Depth= 5.03" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 100-Yr Rainfall=7.00" Area sf CN Description 24,161 98 Paved parking & roofs 6,114 61 >75%Grass cover, Good, HSG B 7,536 65 bare soil /weeds/grass, HSG B 4,014 55 Woods Good HSG B 41,825 83 Weighted Average 17,664 Pervious Area 24,161 Impervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 0.5 50 0.0380 1.55 Sheet Flow, Smooth surfaces n=0.011 P2= 3.20" 0.2 50 0.0400 4.06 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.7 84 0.0160 2.04 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.8 76 0.0100 1.61 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.2 44 0.0450 3.42 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 38 0.2400 7.89 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.5 342 Total Jeffco-Main St 05-10-12 Type ///24-hr 100-Yr Rainfall-7.00" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 ©2006 H droCA© Software Solutions LLC Subcatchment EX 1: Existing Hydrograph 6.1 cis —Runoil 6 Type III 24-hr 100-Yr 5 Rainfall=7.00" Runoff Area=41,825 sf y 4 Runoff Volume=0.402 of 0 Runoff Depth=5.03" LL 3 Flow Length=342' 2 Tc=2.5 m i n CN=83 1- 0- 0 1 2 3 4 5 B 7 8 9 10 11 Ili 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) HydroCAD Post-developed calculations 1-Year Storm P=2.6 inches Jeffco-Main St 05-10-12 Type 11124-hr 1-Yr Rainfa11=2.60" Prepared by Andover Consultants, Inc. H droCAD@ 8.00 s1n 002099 ©2006 H droCAD Software Solutions LLC Subcatchment DEV 1. Developed 1 Runoff = 1.0 cfs @ 12.04 hrs, Volume= 0.067 af, Depth= 1.26" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt=0.05 hrs Type III 24-hr 1-Yr Rainfall=2.60" Area sf CN Description 17,695 98 Paved parking & roofs( was 17045sf) 10,164 61 >75%Grass cover, Good HSG 13 was 10814 sf 27,859 85 Weighted Average 10,164 Pervious Area 17,695 Impervious Area Te Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 0.5 50 0.0380 1.55 Sheet Flow, Smooth surfaces n=0.011 P2= 3.20" 0.1 28 0.0400 4.06 Shallow Concentrated Flow, Paved Kv=20.3 fps 0.2 14 0.0050 1.14 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 11 0.0250 3.21 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.0 116 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.3 44 0.0030 2.88 3.54 Circular Channel(pipe), Diam= 15.0" Area= 1.2 sf Perim=3.9' r= 0.31' n=0.013 0.1 34 0.0059 4.04 4.96 Circular Channel (pipe), Diam= 15.0" Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.013 2.3 297 Total Jeffco-Main St 05-10-12 Type 11124-hr 1-Yr Rainfall=2.60" Prepared by Andover Consultants, Inc. HydroCAD®8.00 s/n 002099 ©2006 HydroCAD Software Solutions LLC Subcatchment DEV 1: Developed 1 Hydrograph I. cfs --Runoii Type III 24-hr 1-Yr Rainfall=2.60" Runoff Area=27,859 sf N Runoff Volume=0.067 of Runoff Depth=1 .26" LL Flow Length=297' Tc=2.3 m i n CN=85 27 0- 0 1 2 3 4 5 B 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 2526 28 29 30 TEme (hours) Jeffco-Main St 05-10-12 Type III 24-hr 1-Yr Rainfall=2.60" Prepared by Andover Consultants, Inc. HydroCAD®8.00 s/n 002099 O 2006 H droCAD Software Solutions LLC Subcatchment DEV 2: Developed 2 Runoff - 0.2 cfs @ 12.07 hrs, Volume= 0.016 af, Depth= 0.58" Runoff by SCS TR-20 method, UH=SCS, Time Span=0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 1-Yr Rainfall=2.60" Area sf CN Description 4,645 98 Paved parking & roofs 7,029 61 >75% Grass cover, Good, HSG B 2,292 55 Woods Good HSG B 13,966 72 Weighted Average 9,321 Pervious Area 4,645 Impervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 0.8 30 0.0050 0.62 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.20" 0.2 32 0.0220 3.01 Shallow Concentrated Flow, Paved Kv=20.3 fps 2.1 220 0.0120 1.76 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 40 0.2400 7.89 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 3.2 322 Total Subcatchment DEV 2: Developed 2 Hydrograph 0.22.. 0.21- 0.2 cfs -Runoff 0.2 0.19 Type III 24-hr 1-Yr 0.18. 0.17- Rai nfall-2;60" 0,6= 0.15 Runoff Area=13,966 sf 0.14 N 0.13 Runoff Vol ume=0.016 of o 0,11 Runoff. Depth=0,58" LL 0.1 0.09 Flow Length-322' 0.08- 0.07 Tc=3,2 min 0.os= 0.05 f'� ```` ee�� ' CN=72 0.04 0.03-: 0.02 0.01 0' 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffc®-Main St 05-10-12 Type /i/24-hr t-Yr Rainfall=2.60" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 ©2006 H droCAD Software Solutions LLC Reach sum: summary Inflow Area = 0.960 ac, Inflow Depth = 0.91" for 1-Yr event Inflow — 1.2 cfs @ 12.06 hrs, Volume= 0.073 of Outflow = 1.2 cfs @ 12.06 hrs, Volume= 0.073 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs /3 Reach sum: summary Hydrograph i 2 cis _lnfiow Outflow Inflow. Area=0.960 ac N O LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 1 a 15 16 i 7 16 19 20 21 22 23 24 7777738 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr 1-Yr Rainfall=2.60" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 0 2006 H droCAD Software Solutions LLC Pond 1 P: DRYWELL Inflow Area = 0.640 ac, Inflow Depth = 1.26" for 1-Yr event Inflow — 1.0 cfs @ 12.04 hrs, Volume= 0.067 of Outflow = 1.0 cfs @ 12.06 hrs, Volume= 0.071 af, Atten= 3%, Lag= 0.9 min Discarded = 0.0 cfs @ 0.00 hrs, Volume= 0.012 of Primary — 1.0 cfs @ 12.06 hrs, Volume= 0.058 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Starting Elev= 54.70' Surf.Area= 406 sf Storage= 513 cf Peak Elev= 55.02' @ 12.06 hrs Surf.Area=406 sf Storage= 572 cf (59 cf above start) Plug-Flow detention time= 118.8 min calculated for 0.059 of (88% of inflow) Center-of-Mass det. time= (not calculated: outflow precedes inflow) Volume Invert Avail.Stora a Storage Description #1 51.63' 45 cf 8.00'W x 28.00%x 0.50'H Prismatoid 112 cf Overall x 40.0%Voids #2 52.13' 728 cf 7.00'W x 26.001 x 4.00'H Prismatolid 773 cf Total Available Storage Device Routing Invert Outlet Devices #1 Primary 54.50' 15.0" x 6.0' long Culvert Ke= 0.500 Outlet Invert= 54.40' S=0.0167 /' Cc= 0.900 n= 0.010 #2 Discarded 0.00' 0.520 inthr Exfiltration over Surface area piscarded OutFlow Max=0.0 cfs @ 0.00 hrs HW=54.70' (Free Discharge) T- -2=Exfiltration (Exfiltration Controls 0,0 cfs) rimary OutFlow Max=1.0 cfs @ 12.06 hrs HW=55.01' TW=54.69' (Dynamic Tailwater) 1=Culvert (Barrel Controls 1.0 cfs @ 3.00 fps) Jeffco-Main St 05-10-12 Type 11124-hr 1-Yr Rainfall=2.60" Prepared by Andover Consultants, Inc. H drgCAD®8.00 s/n 002099 0 2006 H droCAD Software Solutions LLC Pond i P, DRYWELL Hydrograph MP,imay 1.0 cfs Discarded Inflow Area=0.640 ac Peak Elev=55.02' Storage=572 cf 0 0.o fs 0- 0 1 2 3 4 5 7 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type ///24-hr 1-Yr Rainfall=2.60" Prepared by Andover Consultants, Inc. H droCADO 8.00 s/n 002099 4 2006 H droCAD Software Solutions LI.0 Pond cb: CB Inflow Area = 0.640 ac, Inflow Depth = 1.26" for 1-Yr event Inflow = 1.0 cfs @ 12.04 hrs, Volume= 0.067 of Outflow - 1.0 cfs @ 12.04 hrs, Volume= 0.067 af, Atten=0%, I_ag= 0.0 min Primary - 1.0 cfs @ 12.04 hrs, Volume= 0.067 of Routing by Dyn-Stor-Ind method, Time Span=0.00-30.00 hrs, dt= 0.05 hrs/3 Peak Elev= 55.19' @ 12.05 hrs Device Routing Invert Outlet Devices #1 Primary 54.60' 15.0" x 6.0' long Culvert Ke= 0.500 Outlet Invert= 54.50' S=0.0167 '/' Cc= 0.900 n= 0.010 rimary OutFlow Max=1.0 cfs 0 12.04 hrs HW=55.18' TW=55.01' (Dynamic Tailwater) 1=Culvert (Outlet Controls 1.0 cfs @ 2.63 fps) Pond cb: CB Hydrograph 1.Ocfs _Inflow Primary 1. Inflow Area=0.640 ac Peak Elev=5519' 150" x 6.0' Culvert 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type ///24-hr 1-Yr Rainfall-2.60" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 0 2006 H droCAD Software Solutions LLC Pond DMH: DMH Inflow Area = 0.640 ac, Inflow Depth = 1.10" for 1-Yr event Inflow - 1.0 cfs @ 12.06 hrs, Volume= 0.058 of Outflow = 1.0 cfs @ 12.06 hrs, Volume= 0.058 af, Atten= 0%, Lag= 0.0 min Primary - 1.0 cfs @ 12.06 hrs, Volume= 0.058 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs /3 Peak Elev= 54.69' @ 12.06 hrs Device Routing Invert Outlet Devices #1 Primary 53.90' 15.0" x 34.0` long Culvert Ke= 0.500 Outlet Invert= 53.70' S= 0.0059 `/' Cc= 0.900 n= 0.013 Primary OutFiow Max=1.0 cfs @ 12.06 hrs HW=54.69' TW=54.58' (Dynamic Tailwater) L1=Culvert (Outlet Controls 1.0 cfs 0 1.69 fps) Pond DMH: DMH Hydrograph to cfs _Inflow 1. Primary Inflow Area=0.640 ac Peak Elev=54.69' 15.0" x 34.0' Culvert O LL 0 0 1 2 3 4 5 6 7 B 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type If124-hr 1-Yr Rainfall=2.60" Prepared by Andover Consultants, Inc. H droCAD@ 8.00 sln 002099 ©2006 H droCAD Software Solutions LLC Pond Is: Level Spreader Inflow Area = 0.640 ac, Inflow Depth = 1.10" for 1-Yr event Inflow - 1.0 cfs @ 12.06 hrs, Volume= 0.058 of Outflow - 1.0 cfs @ 12.06 hrs, Volume= 0.058 af, Atten= 0%, Lag= 0.1 min Primary = 1.0 cfs @ 12.06 hrs, Volume= 0.058 of Routing by Dyn-Star-Ind method, Time Span=0.00-30.00 hrs, dt= 0.05 hrs/3 Peak Elev= 54.59' @ 12.06 hrs Surf.Area= 94 sf Storage= 43 cf Plug-Flow detention time= 26.7 min calculated for 0.057 of (98% of inflow) Center-of-Mass det. time= 11.6 min ( 826.4 - 814.7) Volume Invert Avail.Stora a Storage Description #1 54.00' 86 of Custom Stage Data(Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store feet s -ft cubic-feet cubic-feet 54.00 50 0 0 54.50 90 35 35 55.00 115 51 86 Device Routing Invert Outlet Devices #1 Primary 54.50' 14.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=1.0 cfs @ 12.06 hrs HW=54.58' TW=0.00' (Dynamic Tailwater) t---1=Broad-Crested Rectangular Weir (Weir Controls 1.0 cfs @ 0.81 fps) Jeffco-Main St 05-10-12 Type 11124-hr f-Yr Rainfa11=2.60" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 ©2006 H droCAD Software Solutions LLC Pond Is: Level Spreader Hydrograph to cis I _inflow 1 Primary Inflow Area-0,640 ac Peak Elev=54.59' Stoirage=43 cf N O LL 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 2-Year Storm P=3.1 inches Jeffco-Main St 05-10-12 Type 11124-hr2-Yr Rainfall=3.10" Prepared by Andover Consultants, Inc. HydroCAD®8 00 s/n 002099 ©2006 HVdroCAD Software Solutions LLC Subcatchment DEV 1: Developed 1 Runoff - 1.4 cfs @ 12.04 hrs, Volume= 0.089 af, Depth= 1.67" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2-Yr Rainfall=3.10" Area sf CN Description 17,695 98 Paved parking & roofs( was 17045sf) 10,164 61 >75% Grass cover, Good HSG B was 10814 sf 27,859 85 Weighted Average 10,164 Pervious Area 17,695 Impervious Area Tc Length Slope Velocity Capacity Description (rein) (feet) (ft/ft) ft/sec cfs 0.5 50 0.0380 1.55 Sheet Plow, Smooth surfaces n= 0.011 P2= 3.20" 0.1 28 0.0400 4.06 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.2 14 0.0050 1.14 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 11 0.0250 3.21 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.0 116 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.3 44 0.0030 2.88 3.54 Circular Channel (pipe), Diam= 15.0" Area= 1.2 sf Perim= 3.9' r= 0.31' n=0.013 0.1 34 0.0059 4.04 4.96 Circular Channel (pipe), Diam= 15.0" Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.013 2.3 297 Total Jeffco-Main St 05-10-12 Type 11124-hr2-Yr Rainfa11=3.10" Prepared by Andover Consultants, Inc. HydroCADO 8.00 s/n 002099 O 2006 H d OCAD Software Solutions LLC Subcatchment DEV 1: Developed 1 Hydrograph 1.4 cfs —Runoff Type III 24-hr 2-Yr Rainfall=3.10" 1 Runoff Area=27,859 sf Runoff Volume=0.089 of Runoff Depth=1 .67" Flow Length=297' Tc=2.3 min CN=85 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr2-Yr Rainfall=3.10" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 O 2006 H droCAD Software Solutions LLC Subcatchment DEV 2: Developed 2 Runoff = 0.3 cfs @ 12.06 hrs, Volume= 0.023 af, Depth= 0.87" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2-Yr Rainfall=3.10" Area sf CN Description 4,645 98 Paved parking & roofs 7,029 61 >75% Grass cover, Good, HSG B 2,292 55 Woods Good HSG B 13,966 72 Weighted Average 9,321 Pervious Area 4,645 Impervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 0.8 30 0.0050 0.62 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.20" 0.2 32 0.0220 3.01 Shallow Concentrated Flow, Paved Kv= 20.3 fps 2.1 220 0.0120 1.76 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 40 0.2400 7.89 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 3.2 322 Total Subcatchment DEV 2: Developed 2 Hydrograph 0.36- 0.34 0.3 cfs -Runoff 0.32: 0.3: Type III 24-hlr 2-Yr 0.28: Rainfall=3.1 Orr 0.26 0.24 Runoff Area=13,966 sf 0.22 0.2 Runoff Volume=0.023 of 0 0.,& Runoff Depth=0.87" 0.1 4 Flow Length-322` 0.12 Tc=3.2 m i n 0.08 CN=72 0.06- 0.04 0.02 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr2-Yr Ralnfa11=3.10" Prepared by Andover Consultants, Inc. HydroCADO 8.00 s/n 002099 0 200E HydroCAD Software Solutions LLC Reach sum: summary Inflow Area = 0.960 ac, Inflow Depth = 1.29" for 2-Yr event Inflow - 1.7 cfs @ 12.06 hrs, Volume= 0.103 of Outflow - 1.7 cfs 0 12.06 hrs, Volume= 0.103 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Reach sum: summary Hydragraph 1.7 efs Inllow Outflow Inflow Area=0.960 ac N 3 0 fl 1 2 3 A 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr2-Yr Rainfall=3.10" Prepared by Andover Consultants, Inc. H droCADO 8.00 s/n 002099 ©2006 H droCAD Software Solutions LLC Pond 1 P: DRYWELL Inflow Area = 0.640 ac, Inflow Depth = 1.67" for 2-Yr event Inflow = 1 A cfs @ 12.04 hrs, Volume= 0.089 of Outflow = 1.3 cfs @ 12.06 hrs, Volume= 0.093 af, Atten= 2%, Lag= 0.8 min Discarded = 0.0 cfs @ 0.00 hrs, Volume= 0.012 of Primary - 1.3 cfs @ 12.06 hrs, Volume= 0.081 of Routing by Dyn-Stor-Ind method, Time Span=0.00-30.00 hrs, dt= 0.05 hrs /3 Starting Elev= 54.70' Surf.Area= 406 sf Storage= 513 cf Peale Elev= 55.12' @ 12.06 hrs. Surf.Area= 406 sf Storage= 590 cf (77 cf above start) Plug-Flow detention time= 93.7 min calculated for 0.081 of (91%of inflow) Center-of-Mass det. time=0.4 min ( 824.5 - 824.1 ) Volume Invert Avail.Stora a Storage Description #1 51.63' 45 cf 8.00'W x 28.00'L x 0.50'H Prismatoid 112 cf Overall x 40.0%Voids #2 52.13' 728 cf 7.00'W x 26.00'L x 4.00'H Prismatoid 773 cf Total Available Storage Device Routing Invert Outlet Devices #1 Primary 54.50' 15.0" x 6.0' tong Culvert Ke= 0.500 Outlet Invert= 54.40' S= 0.0167 '/' Cc=0.900 n= 0.010 #2 Discarded 0.00' 0.520 in/hr Exfiltration over Surface area Iiscarded OutFlow Max=0.0 cfs @ 0.00 hrs HW=54.70' (Free Discharge) L2=Exfiltration (Exfiltration Controls 0.0 cfs) Primary OutFlow Max=1.3 cfs @ 12.06 hrs HW=55.11' TW=54.75' (Dynamic Tailwater) t-1=Culvert (Barrel Controls 1.3 cfs @ 3.18 fps) Jeffco-Main St 05-10-12 Type 11124-hr2-Yr Rainfall=3.10" Prepared by Andover Consultants, Inc. HydroCAD®8.00 s/n 002099 O 2006 HydroCAD Software Solutions LLC Pond 1 P: DRYWELL Hydrograph —Inflow 1.3 cfs Outflow Discarded Inflow Area=0.640 ac Primary Peak Elev=55.12' 1 Storage=590 cf 0 LL 0.0 is fl 0 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr2-Yr Rainfall=3.10" Prepared by Andover Consultants, Inc. H droCADO 8.00 sln 002099 ©2006 H droCAD Software Solutions LLC Pond cb: CB Inflow Area = 0.640 ac, Inflow Depth = 1.67" for 2-Yr event Inflow - 1.4 cfs @ 12.04 hrs, Volume= 0.089 of Outflow - 1.4 cfs @ 12.04 hrs, Volume= 0.089 af, Atten=0%, Lag= 0.0 min Primary = 1.4 cfs @ 12.04 hrs, Volume= 0.089 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Peak Nev= 55.31' @ 12.05 hrs Device Routing Invert Outlet Devices #1 Primary 54.60' 15.0" x SA' long Culvert Ke= 0.500 Outlet Invert= 54.50' S=0.0167 Y' Cc= 0.900 n=0.010 Primary OutFlow Max=1.3 cfs @ 12.04 hrs HW=55.30' TW=55.11' (Dynamic Tailwater) t-1=Culvert (Outlet Controls 1.3 cfs @ 2.76 fps) Pond cb: CB Hydrograph 1.4 cfs I —Inflow —Primary Inflow Area=0.640 ac Peak Elev_55.31 ' 15.0" x 6.0' Culvert N 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr2-Yr Rainfall=3.10" Prepared by Andover Consultants, Inc. H droCAD@ 8.00 s/n 002099 ©2006 H droCAD Software Solutions LLC Pond DMH: DMH Inflow Area = 0.640 ac, Inflow Depth = 1.51" for 2-Yr event Inflow = 1.3 cfs @ 12.06 hrs, Volume= 0.081 of Outflow 1.3 cfs @ 12.06 hrs, Volume= 0.081 af, Atten= 0%, Lag= 0.0 min Primary - 1.3 cfs @ 12.06 hrs, Volume= 0.081 of Routing by Dyn-Star-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Peak Elev= 54.76' @ 12.06 hrs Device Routing Invert Outlet Devices #1 Primary 53.90' 15.0" x 34.0' long Culvert Ke= 0.500 Outlet Invert= 53.70' S= 0.0059 /' Cc= 0.900 n= 0.013 rimary OutFlow Max=1.3 cfs @ 12,06 hrs HW=54.75' TW=54.60' (Dynamic Tailwater) 1=Culvert (Outlet Controls 1.3 cfs @ 2.07 fps) Pond DMH: DMH Hydrograph 1.3 Cfs —InfIOW Primary Inflow Area=0.640 ac Peak Elev_54.76' 1 15.0"' x 34.0' Culvert N O 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr 2-Yr Rainfall=3.10" Prepared by Andover Consultants, Inc. H droCADO 8.00 s/n 002099 0 2006 H droCAD Software Solutions LLC Pond Is. Level Spreader Inflow Area = 0.640 ac, Inflow Depth = 1.51" for 2-Yr event Inflow = 1.3 cfs @ 12.06 hrs, Volume= 0.081 of Outflow = 1.3 cfs @ 12.06 hrs, Volume= 0.080 A Atten= 0%, Lag= 0.1 min Primary -- 1.3 cfs 0 12.06 hrs, Volume= 0.080 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Peak Elev= 54.61' @ 12.06 hrs Surf.Area= 95 sf Storage=45 cf Plug-Flow detention time= 19.6 min calculated for 0.079 of (98%of inflow) Center-of-Mass det. time= 8.5 min ( 821.5 - 813.1 ) Volume Invert Avail.Stora a Storage Description #1 54.00' 86 cf Custom Stage Data(Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet 54.00 50 0 0 54.50 90 35 35 55.00 115 51 86 Device Routing Invert Outlet Devices #1 Primary 54.50' 14.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=1.3 cfs @ 12.06 hrs HW=54.60' TW=0.00' (Dynamic Tailwater) t--1=Broad-Crested Rectangular Weir (Weir Controls 1.3 cfs @ 0.90 fps) Jeffco-Main St 05-10-12 Type If124-hr 2-Yr Rainfall=3.10" Prepared by Andover Consultants, Inc. HydroCAD®8.00 sln 002099 ©2006 HydroCAD Software Solutions LLC Pond Is: Level Spreader Hydrograph 1,3 cfs »Inflow Primary I nflow Area=0.640 ac Peak Elev-54.61 ' Storage-45 cf N O LL 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 10-Year Storm P=4.5 inches Jeffco-Main St 05-10-12 Type Ill 24-hr 10-Yr Rainfall=4.50" Prepared by Andover Consultants, Inc. H droCiAD®8.00 s/n 002099 ©2006 H droCAD Software Solutions LLC Subcatchment DEV 1: Developed 1 Runoff = 2.4 cfs @ 12.04 hrs, Volume= 0.155 af, Depth= 2.91" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 10-Yr Rainfall=4.50" Area sf CN Descri tion 17,695 98 Paved parking & roofs( was 17045sf) 10,164 61 >75% Grass cover, Good HSG B was 10814 sf 27,859 85 Weighted Average 10,164 Pervious Area 17,695 Impervious Area Tc Length Slope Velocity Capacity Description min feet ftlft ft/sec cfs 0.5 50 0.0380 1.55 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.20" 0.1 28 0.0400 4.06 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.2 14 0.0050 1.14 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 11 0.0250 3.21 Shallow Concentrated Flow, Paved Kv=20.3 fps 1.0 116 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.3 44 0.0030 2.88 3.54 Circular Channel (pipe), Diam= 15.0" Area= 1.2 sf Perim 3.9' r=0.31` n= 0.013 0.1 34 0.0059 4.04 4.96 Circular Channel (pipe), Diam= 15.0" Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.013 2.3 297 Total Jeffco-Main St 05-10-12 Type U124-hr 10-Yr Rainfall=4.50" Prepared by Andover Consultants, Inc. H droCAD®8.00 sln 002099 ©2006 H droCAD Software Solutions LLC Subcatchment DEV 1: Developed 1 Hydrograph 2.4 cis I —Runoff Type III 24-hr 10-Yr 2 Rainfall=4.50" Runoff Area=27,859 sf N Runoff Volume=0.155 of 3 Runoff Depth=2.91 "0 1 Flow Length=297' Tc=2.3 m i n CN=85 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 i 2 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr i0-Yr Rainfall=4.50" Prepared by Andover Consultants, Inc. HydroCAD®8.00 s/n 002099 ©2006 HydroCAD Software Solutions LLC Subcatchment DEV 2: Developed 2 Runoff - 0.7 cfs @ 12.06 hrs, Volume= 0.049 af, Depth= 1.82" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 10-Yr Rainfall=4.50" Area s# CN Description 4,645 98 Paved parking & roofs 7,029 61 >75%Grass cover, Good, HSG B 2,292 55 Woods Good HSG B 13,966 72 Weighted Average 9,321 Pervious Area 4,645 Impervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 0.8 30 0.0050 0.62 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.20" 0.2 32 0.0220 3.01 Shallow Concentrated Flow, Paved Kv=20.3 fps 2.1 220 0.0120 1.76 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 40 0.2400 7.89 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 3.2 322 Total Subcatchment DEV 2: Developed 2 Hydrograph 0.8 0.75- 0.7 cfs --Ftunaff Type III 24-hr, 1 o-Yr 0.65� 0.6 Rainfall 4.50" 0.55_ Runoff Area=13,966 sf 0.5 ° _ Runoff Volume=0.049 of 0.4 - LRff Depth=1 .82" " a w, Length=322' 0.25 Tc=3.2 min 0.2: CN=72 0.15 0.05 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr 10-Yr Rainfa11=4.50" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 0 2006 H droCAD Software Solutions LLC Reach sum: summary Inflow Area - 0.960 ac, Inflow Depth = 2.43" for 10-Yr event Inflow = 3.1 cfs @ 12.05 hrs, Volume= 0.194 of Outflow = 3.1 cfs @ 12.05 hrs, Volume= 0.194 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs /3 Reach sum: summary Hydrograph 3.1 cfs _Inflow 3 Outflow Inflow Areas0.960 ac 2 N 3 O 1 0 1 2 3 4 5 6 7 B 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr 10-Yr Rainfall=4.50" Prepared by Andover Consultants, Inc. HydroCADO 8.00 s/n 002099 ©2006 HydroCAD Software Solutions LLC Pond 1 P: DRYWELL Inflow Area = 0.640 ac, Inflow Depth = 2.91" for 10-Yr event Inflow - 2.4 cfs @ 12.04 hrs, Volume= 0.155 of Outflow = 2.3 cfs @ 12.05 hrs, Volume= 0.159 af, Atten= 1%, Lag=0.7 min Discarded = 0.0 cfs @ 0.00 hrs, Volume= 0.012 of Primary = 2.3 cfs @ 12.05 hrs, Volume= 0.146 of Routing by Dyn-Star-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Starting Elev= 54.70' Surf.Area= 406 sf Storage= 513 cf Peak Elev= 55.37' @ 12.05 hrs Surf.Area= 406 sf Storage= 635 cf (122 cf above start) Plug-Flow detention time= 61.8 min calculated for 0.147 of (95% of inflow) Center-of-Mass det. time= 3.6 min ( 811.9 - 808.3 ) Volume Invert Avail.Stora a Storage Description #1 51.63' 45 cf 8.00'W x 28.001 x 0.50'H Prismatoid 112 cf Overall x 40.0%Voids #2 52.13' 728 cf 7.00'W x 26.001 x 4.00'H Prismatoid 773 cf Total Available Storage Device Routino Invert Outlet Devices #1 Primary 54.50' 15.0" x 6.0' long Culvert Ke=0.500 Outlet Invert= 54.40' S= 0.0167 '/' Cc= 0.900 n= 0.010 #2 Discarded 0.00' 0.520 inlhr Exfiltration over Surface area Discarded OutFlow Max=0.0 cfs @ 0.00 hrs HW=54.70' (Free Discharge) t2=Exfiltration (Exfiltration Controls 0.0 cfs) Primary OutFlow Max=2.3 cfs @ 12.05 hrs HW=55.37' TW=54.93' (Dynamic Tailwater) t--1=Culvert (Barrel Controls 2.3 cfs @ 3.59 fps) Jeffco-Main St 05-10-12 Type 11124-hr 10-Yr Rainfall=4.50" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 ©2006 H droCA© Software Solutions LLC Pond 1 P: ©RYWELL Mydrograph 2.3 cfs —Inflow Outflow —Discarded Inflow Airea=0.640 ac —Primary 2 Peak Elev-55.37' Storage=635 cf N O LL 1- 0.c fs 0 0 1 2 3 4 5 B 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type ///24-hr 10-Yr Rarnfal1=4.50" Prepared by Andover Consultants, Inc. HydroCADO 8.00 s/n 002099 0 2006 HydroCAD Software Solutions LLC Pond cb: CB Inflow Area = 0.640 ac, Inflow Depth = 2.91" for 10-Yr event Inflow = 2.4 cfs @ 12.04 hrs, Volume= 0.155 of Outflow - 2.4 cfs @ 12.04 hrs, Volume= 0.155 af, Atten= 0%, Lag= 0.0 min Primary -- 2.4 cfs @ 12.04 hrs, Volume= 0.155 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Peak Elev= 55.60' @ 12.05 hrs Device Routing Invert Outlet Devices #1 Primary 54.60' 15.0" x 6.0' long Culvert Ke= 0.500 Outlet Invert= 54.50' S= 0.0167 '/' Cc= 0.900 n=0.010 Primary OutFlow Max=2.3 cfs @ 12.04 hrs HW=55.58' TW=55.35' (Dynamic Tailwater) 't -1=Culvert (Outlet Controls 2.3 cfs @ 3.07 fps) Pond cb: CB Hydrograph 2.4 cfs —iWiow —Primary Inflow. Area-0.640 ac 2, Peak Elev-55.60' 15.0" x 6.0` Culvert 3 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) JeffCo-Mein St 05-10-12 Type ///24-hr 10-Yr Rainfall=4.50" Prepared by Andover Consultants, Inc. H droCAD@ 8.00 s/n 002099 ©2006 H droCAD Software Solutions LL.0 Pond DMH: DMH Inflow Area = 0.640 ac, Inflow Depth = 2.75" for 10-Yr event Inflow = 2.3 cfs @ 12.05 hrs, Volume= 0.146 of Outflow - 2.3 cfs @ 12.05 hrs, Volume= 0.146 af, Atten= 0%, Lag= 0.0 min Primary - 2.3 cfs @ 12.05 hrs, Volume= 0.146 of Routing by Dyn-Star-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Peak Elev= 54.94' @ 12.05 hrs Device Routing_ Invert Outlet Devices #1 Primary 53.90' 15.0" x 34.0' long Culvert Ke= 0.500 Outlet Invert= 53.70' S= 0.0059 /' Cc= 0.900 n=0.013 rimary OutFlow Max=2.3 cfs @ 12.05 hrs HW=54.93' TW=54.65' (Dynamic Tailwater) 1=Culvert (Outlet Controls 2.3 cfs @ 2.89 fps) Pond DMH: DMH Hydrograph 2.3 cis —In{low Primary Inflow Area=0.640 ac 2- Peak Elev=54.94' 15.0" x 34.0' Culvert n 0 1 2 3 4 5 6 7 6 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr 10-Yr Rainfall=4.50" Prepared by Andover Consultants, Inc. H droCADO 8.00 sln 002099 ©2006 H droCAD Software Solutions LLC Pond Is: Level Spreader Inflow Area = 0.640 ac, Inflow Depth = 2.75" for 10-Yr event Inflow 2.3 cfs @ 12.05 hrs, Volume= 0.146 of Outflow - 2.3 cfs @ 12.05 hrs, Volume= 0.146 af, Atten= 0%, Lag=0.1 min Primary = 2.3 cfs @ 12.05 hrs, Volume= 0.146 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-30,00 hrs, dt= 0.05 hrs/3 Peak Elev= 54.65' @ 12.05 hrs Surf.Area= 98 sf Storage= 49 c# Plug-Flow detention time= 11.4 min calculated for 0.145 of (99% of inflow) Center-of-Mass dot. time= 4.7 min ( 809.2 - 804.5 ) Volume Invert Avail.Stora a Storage Description #1 54.00' 86 cf Custom Stage Data(Prismatic) Listed below (Recale) Elevation Surf.Area Inc.Store Cum.Store feet s -ft cubic-feet cubic-feet 54.00 50 0 0 54.50 90 35 35 55.00 115 51 86 Device Routing Invert Outlet Devices #1 Primary 54.50' 14.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=2.3 cfs @ 12,05.hrs HW=54.65' TW=0.00' (Dynamic Tailwater) L1=Broad-Crested Rectangular Weir (Weir Controls 2.3 cfs @ 1.09 fps) Jeffco-Main St 05-10-12 Type 11124-hr 10-Yr Ralnfall=4.50° Prepared by Andover Consultants, Inc. H droCAD®.8.00 s/n 002099 0 2006 H droCAD Software Solutions LLC Pond Is: Level Spreader Hydrograph 2.3 cis — Inllow Primary Inflow Area=0.640 ac 2-Peak Elev=54.65' Storage=49 d Hf O rL i- 0- 0 i 2 3 4 5 6 7 B 9 10 11 12 13 14 15 1S 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 100-Year Storm P=7.0 inches Jeffco-Main St 05-10-12 Type 11124-hr 100-Yr Rainfall=7.00" Prepared by Andover Consultants, Inc. H droCAD®8.00 s/n 002099 0 2006 H droCAD Software Solutions LLC Subcatchment DEV 1: Developed 1 Runoff = 4.2 cfs @ 12.04 hrs, Volume= 0.280 af, Depth= 5.25" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 100-Yr Rainfall=7.00" Area sf CN Description 17,695 9B Paved parking & roofs( was 17045sf) 10,164 61 >75%Grass cover, Good HSG 8 was 10814 sf 27,859 85 Weighted Average 10,164 Pervious Area 17,695 Impervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/see cfs 0.5 50 0.0380 1.55 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.20" 0.1 28 0.0400 4.06 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.2 14 0.0050 114 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 11 0.0250 3.21 Shallow Concentrated Flow, Paved Kv=20.3 fps 1.0 116 0.0100 2.03 Shallow Concentrated Flow, Paved Kv=20.3 fps 0.3 44 0.0030 2.88 3.54 Circular Channel (pipe), Diam= 15.0" Area= 1.2 sf Perim= 3.9` r= 0.31' n=0.013 0.1 34 0.0059 4.04 4.96 Circular Channel (pipe), Diam= 15.0" Area= 1.2 sf Perim= 3.9' r= 0.31' n=0.013 2.3 297 Total Jeffco-Main St 05-10-12 Type Iii 24-hr 100-Yr Rainfall=7.00° Prepared by Andover Consultants, Inc. HydroCADO 8.00 sln 002099 0 2006 HydroCAD Software Solutions LLC Subcatchment DEV 1: Developed 1 Hydrograph 4.2 cis —Runoii 4 Type III 24-hr 100-Yr Rainfall=7.00" 3. Runoff Area=27,859 sf Runoff Volume=0.280 of 0 0 Runoff Depth=5.25" LL 2 Flow Length=297' Tc=2.3 min 1 CN=85 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type IIl 24-hr 100-Yr Rainfall=7.00" Prepared by Andover Consultants, Inc. H droCAD@ 8.00 sin 002099 ©2006 H droCAD Software Solutions LLC Subcatchment DEV 2: Developed 2 Runoff - 1.6 cfs @ 12.05 hrs, Volume= 0.102 af, Depth= 3.83" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 100-Yr Rainfall=7.00" Area s# CN Description 4,645 98 Paved parking & roofs 7,029 61 >75% Grass cover, Good, HSG B 2,292 55 Woods Good HSG B 13,966 72 Weighted Average 9,321 Pervious Area 4,645 Impervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 0.8 30 0.0050 0.62 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.20" 0.2 32 0.0220 3.01 Shallow Concentrated Flow, Paved Kv= 20.3 fps 2.1 220 0.0120 1.76 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 40 0.2400 7.89 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 3.2 322 Total Subcatchment DEV 2: Developed 2 Hydrograph 1.6 cfs —Runoff Type III 24-hr 100-Yr Rainfall=7.00" Runoff Alrea=13,966 sf N 1 Runoff Volume=0.102 of Runoff Depth=3.83" Flow Length=322' Tc=3.2 min CN=72 O 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr 100-Yr Rainfall=7.00" Prepared by Andover Consultants, Inc. H droCADO 8.00 s/n 002099 0 2006 H droCAD Software Solutions LLC Reach sum: summary Inflow Area = 0.960 ac, Inflow Depth = 4.66" for 100-Yr event Inflow - 5.7 cfs @ 12.05 hrs, Volume= 0.373 of Outflow = 5.7 cfs @ 12.05 hrs, Volume= 0.373 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Reach sum: summary Hydrograph 8-. 5.7 cfs _Inflow Outflow Inflow Area=0.964 ac 5 4 N 0 3. iL 2 1... 0 0 1 2 3 4 5 fi 7 8 9 10 11 12 13 14 15 18 17 18 19 20 21 22 23 24 25 2fi 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type H/24-hr 100-Yr Rainfaff=7.00" Prepared by Andover Consultants, Inc. HydroCADO 8.00 s/n 002099 ©2006 HydroCAD Software Solutions LLC Pond 1 P: DRYWELL Inflow Area = 0.640 ac, Inflow Depth = 5.25" for 100-Yr event Inflow - 4.2 cfs @ 12.04 hrs, Volume= 0.280 of Outflow - 4.1 cfs @ 12.05 hrs, Volume= 0.283 af, Atten= 1%, Lag= 0.6 min Discarded - 0.0 cfs @ 0.00 hrs, Volume= 0.012 of Primary - 4.1 cfs @ 12.05 hrs, Volume= 0.271 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Starting Elev= 54.70' Surf.Area= 406 sf Storage= 513 cf Peak Elev= 55.76' @ 12.05 hrs Surf.Area=406 sf Storage= 706 cf (193 cf above start) Plug-Flow detention time= 39.6 min calculated for 0.272 of (97%of inflow) Center-of-Mass det. time=4.3 min ( 795.9 - 791.7) Volume Invert Avail.Storage Storage Description #1 51.63' 45 cf 8.00'W x 28.00'L x 0.50'H Prismatoid 112 cf Overall x 40.0% Voids #2 52.13' 728 cf 7.00'W x 26.00'L x 4.00'H Prismatoid 773 cf Total Available Storage Device Routing Invert Outlet Devices #1 Primary 54.50' 15.0" x 6.0' long Culvert Ke= 0.500 Outlet Invert= 54.40' S= 0.0167 '/' Cc= 0.900 n= 0.010 #2 Discarded 0.00' 0.520 irt/hr Exfiltration over Surface area Qiscarded OutFlow Max=0.0 cfs @ 0.00 hrs HW=54.70' (Free Discharge) r--2=Exfil#ration (Exfiltration Controls 0.0 cfs) Primary OutFlow Max=4.1 cfs @ 12.05 hrs HW=55,76' TW=55.23' (Dynamic Tailwater) L1=Culvert (Barrel Controls 4.1 cfs @ 4.14 fps) Jeffco-Main St 05-10-12 Type 11124-hr 100-Yr Rainfall=7.00" Prepared by Andover Consultants, Inc. HydroCAD®8.0O sln 002099 0 2006 HydroCAD Software Solutions LLC Pond 1 P: DRYWELL Hydrograph Inflow 4.i CIS Outflow Discarded 4 Inflow Area=0.640 ac —Primary Peak Elev=55.76' 3 Storage-706 cf O IL 2. 1 0.0 Cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr 100-Yr Rainfa11=7.00" Prepared by Andover Consultants, Inc. HydroCADO 8.00 s/n 002099 ©2006 HydroCAD Software Solutions LLC Pond cb: CB Inflow Area = 0.640 ac, Inflow Depth = 5.25" for 100-Yr event Inflow = 4.2 cfs @ 12.04 hrs, Volume= 0.280 of Outflow = 4.2 cfs @ 12.04 hrs, Volume= 0.280 af, Atten= 0%, Lag= 0.0 min Primary - 4.2 cfs @ 12.04 hrs, Volume= 0.280 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Peak Elev= 56.26' @ 12.05 hrs Device Routing Invert Outlet Devices #1 Primary 54.60' 15.0" x 6.0' long Culvert Ke= 0.500 Outlet Invert= 54.50' S= 0.0167 '/' Cc= 0.900 n= 0.010 Primary Outflow Max=4.0 cfs @ 12.04 hrs HW=56.19' TW=55.72' (Dynamic Tailwater) t1=Culvert (Inlet Controls 4.0 cfs @ 3.29 fps) Pond cb: CB Hydrograph 4.2 c(s _irrtf0w Primary Inflow Area'0.640 ac Peak Elev=56.26' 3. 15.0" x 6.0' Culvert O U. 2- - 1 0 0 1 2 3 4 5 6 7 6 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type I//24-hr 100-Yr Rainfall=7.00" Prepared by Andover Consultants, Inc. HydroCADO 8.00 s/n 002099 ©2006 HydroCAD Software Solutions LLC Pond DMH: DMH Inflow Area = 0.640 ac, Inflow Depth = 5.09" for 100-Yr event Inflow = 4.1 cfs @ 12.05 hrs, Volume= 0.271 of Outflow = 4.1 cfs @ 12.05 hrs, Volume= 0.271 af, Atten= 0%, Lag= 0.0 min Primary = 4.1 cfs @ 12.05 hrs, Volume= 0.271 of Routing by Dyn-Stor-Ind method, Time Span=0.00-30.00 hrs, dt= 0.05 hrs /3 Peak Elev= 55.23' @ 12.05 hrs Device Routing Invert Outlet Devices #1 Primary 5&90' 15.0" x 34.0' long Culvert Ke= 0.500 Outlet Invert= 53.70' S= 0.0059 '/' Cc= 0.900 n= 0.013 Primary OutlFlow Max=4.1 cfs @ 12.05 hrs HW=55.23' TW=54.72' (Dynamic Tailwater) L1=Culvert (Outlet Controls 4.1 cfs @ 3.93 fps) Pond DMH: DMH Hydrograph 4.1 cis -�Inflow Pnmary 4 Inflow Area=0.640 ac Peak Elev=55.23' 3 15.011 x 34.0" Culvert ;n fl ILL 2- 1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1b 16 !7 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Jeffco-Main St 05-10-12 Type 11124-hr 100-Yr Rainfall=7.00" Prepared by Andover Consultants, Inc. H droCAD@ 8.00 sln 002099 ©2006 H droCAD Software Solutions LLC Pond Is: Level Spreader Inflow Area - 0.640 ac, Inflow Depth = 5.09" for 100-Yr event Inflow = 4.1 cfs @ 12.05 hrs, Volume= 0.271 of Outflow = 4.1 cfs @ 12.05 hrs, Volume= 0.270 af, Atten= 0%, Lag= 0.1 min Primary - 4.1 cfs @ 12.05 hrs, Volume= 0.270 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/3 Peak Elev= 54.72' @ 12.05 hrs Surf.Area= 101 sf Storage= 56 cf Plug-Flow detention time= 6.4 min calculated for 0.270 of (99% of inflow) Center-of-Mass det. time= 2.5 min ( 793.8 - 791.3 ) Volume Invert Av_ail.StorageStorage Description #1 54.00' 86 cf Custom Stage Data(Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 54.00 50 .._.. 0 54.50 90 35 35 55.00 115 51 86 Device Routing Invert Outlet Devices #1 Primary 54.50' 14.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=4.1 cfs @ 12.05 hrs HW=54.72' TW=0.00' (Dynamic Tailwater) L1-Broad-Crested Rectangular Weir (Weir Controls 4.1 cfs @ 1.32 fps) Jeffco-Main St 05-10-12 Type 11124-hr 100-Yr Rainfal1=7.00° Prepared by Andover Consultants, Inc. W droCADO 8.00 sln 002099 ©2006 W droCAD Software Solutions LLC Pond Is: Level Spreader Hydrograph 4.1 cis I —Inflow 17 Primary 4 Inflow Area=0.640 ac Peak Elea=54.72' 3 Storage=56 cf a IL 2- 1- 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 18 '7111 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Drainage Divide Maps