DRAINAGE REPORT FOR THORNTON SELF STORAGE THORNTON, COLORADO

DRAINAGE REPORT FOR THORNTON SELF STORAGE THORNTON, COLORADO Prepared by: Bowman Consulting 603 Park Point Dr. Suite 100 Golden, CO 80401 (303)-801-2900 June 29, 2015 Revised August 14, 2015

CERTIFICATE SHEET DCB Construction hereby certifies that the drainage facilities for the Thornton Self-Storage will be constructed according to the design presented in this report. I understand that the City of Thornton does not and shall not assume liability for the drainage facilities designed and/or certified by my engineer. I understand that the City of Thornton reviews drainage plans but cannot, on behalf of Thornton Self-Storage, guarantee that final drainage design review will be absolve DCB Construction and/or their successors and/or assigns of future liability for improper design. I further understand that approval of the Plat and/or Development Permit does not imply approval of my engineer s drainage design. ATTEST: Name of Responsible Party Notary Public Authorized Signature I hereby certify that this report (plan) for the final drainage design of Thornton Self-Storage was prepared by me (or under my direct supervision) in accordance with the provisions of the City of Thornton Standards and Specifications for the Design and Construction of Public and Private Improvements for the Responsible Parties thereof. I understand that the City of Thornton does not and shall not assume liability for drainage facilities designed by others. Charles Edward Weiss Registered Professional Engineer State of Colorado No. 28850

GENERAL LOCATION AND DESCRIPTION The Thornton Self-Storage site is located in the Southeast Quarter of Section 34, Township 1 South, Range 68 West of the 6 th Principal Meridian and takes up approximately 5.166 acre portion of Lot 1, Block 1, Qwest Thornton Central Office Subdivision on the west side of North Washington Street. The site s surrounding area is made up of commercial and industrial properties. There is a 40 foot right of way adjacent to the north property line that contains drainage pipes and will be replatted as a drainage easement. An existing STOR-N-LOCK facility is located on the other side of the right of way. The west side of the site is bounded by a day care facility and Newcomb Spring of Colorado manufacturing facility which front Pennsylvania Street. Qwest has a commercial building south of the site with a parking lot and detention basin adjacent to the property. The northeast corner of the site contains a gas regulator station that is in a 30 foot by 50 foot easement. Just west of the gas regulator station is a 42 inch storm drain which daylights into a grass lined channel in a 40 foot drainage easement that runs southeast from the north property line to the site s ultimate outfall, an existing 6 x 3 RCB that goes under Washington Street into Brantner Gulch. Currently the site is undeveloped and covered with sparse vegetation and native grasses. Proposed for the site is an eight building self-storage facility. The main building will be on the east side of the site near Washington Street. It is planned to be a two story structure with water and sewer services, climate-controlled, storage building, approximately 36,900 square feet. The other seven buildings will be single story structures for storage only ranging from approximately 6,000 to 12,000 square feet with driving lanes in between them. A detention and water quality facility is proposed just south of the main building. No irrigation facilities are proposed for this site. DRAINAGE BASINS AND SUB-BASINS The project area was included in the Flood Insurance Rate Map (FIRM) for Adams County, Panel No. 08001C0311 H, revised March 5, 2007. The site does not lie within a Flood Hazard Area as designated by the FIRM. A copy of the FIRM is included at the back of this report. The site drains under Washington Street to Brantner Gulch. The gulch flows easterly to the South Platte River. The South Platte is located about five miles east of the site. The site area does not lie within a major basin study area. Historically, the site generally sloped from southwest to northeast at a uniform 2% towards Washington Street. This historic drainage pattern will not be altered by the proposed additions.

The area was divided into six major drainage basins, five offsite (OS) and the onsite basin which consist of four sub-basins, converging at the culvert crossing under Washington Street. The offsite basins encompass 57.5 acres of commercial/industrial properties, streets, and open space. Areas south of 120 th Avenue are in the City of Northglenn. Pam Acre, Northglenn s Floodplain Administration Stormwater Coordinator, stated that runoff south of 120 th Ave and east of the Farmers Highline Canal is intercepted in piping and directed east along 120 th Ave until they turn north at Race Street and discharge into Brantner Gulch. Basin OS1 includes sub-basins A-J, N-P, R and S as seen in the appendix and starts on the north side of 120 th Ave at the Farmers Highline Canal then continues all the way down Pennsylvania Street, collecting flow from commercial properties on the west side of Pennsylvania Street, to the intersection of Washington Street. Minor flows are collected in a series of inlets as described in the following sentences, major flows continue to Washington Street. There the flow turns south to be collected in the inlets at the culvert on the east side of the Thornton Self-Storage facility crossing Washington Street (design point #3). There are inlets located approximately two thirds of the way down Pennsylvania Street (design point #1) that given the pipe size and slope can only handle the 5 year storm event interception and piped north of the day care site into the storm sewer within the 40 foot Right of Way along the north side of the project site. Another set of inlets located on Pennsylvania Street approximately 275 feet west of the intersection with Washington Street (design point #2) are also sized to pick up the 5 year flow given the pipe size and slope at that point. That flow is piped south through the STOR-N-LOC property where it ties into the existing drainage system in the 40 foot Right of Way. These inlets are located in the sump of Pennsylvania Street. Basin OS2 is located directly north of the Thornton Self Storage Site and consist of the drainage from the STOR-N-LOC facility, which flows to their detention basin on the east side of their site and is piped to the 42 inch drainage pipe located in the 40 foot Right of Way near the gas regulator station (design point #6). For the purpose of calculations this area is called sub-basin Q in the appendix of this report. Basin OS3 is located south of the Thornton Self Storage Site and is made up of sub-basins T-W, beginning at the intersection of 120 th Ave and Pennsylvania Street and continues along the north side of 120 th Ave moving east and including the commercial sites north of 120 th Ave. It then turns north at Washington Street, picking up flow from the west side of the street and continues north to the inlets at the existing 6 X 3 concrete box culvert to cross Washington Street (design point #4). There is an inlet on the west side of Washington Street before the first intersection that picks up the 5 year flow to that point and pipes the flow through a 24 inch RCP out falling into the open channel at the entrance to the 6 X 3 concrete box culvert. Basin OS4 is the adjacent Qwest property that was made up of four sub-basins in their drainage report. OS4-1 s flow is directed into the Qwest detention basin which is then piped across the Self-Storage site to the channel opening at the Washington Street box culvert crossing (design point #6). OS4-2 s flow goes out the south drive access and into Washington Street. Flow in area OS4-3 is channeled to a culvert opening that ties into the existing storm system in Washington Street Right of Way. OS4-4 follows the historical flow path to the northeast corner of the parking

lot and through a curb opening onto the Self-Storage site. For the purpose of this report the site was broken into sub-basins Y and Z. Basin OS5 includes three commercial sites, sub-basins K-L on the Historic Drainage exhibit in the appendix, on the east side of Pennsylvania Street along with open space, sub-basin X, south of the first commercial site that extends along the back of the commercial sites down to the Self- Storage site (design point #5). The commercial sites have onsite detention that releases to a channel flowing along the west side of the Self-Storage property, then continue around the north side of the Self-Storage site joining with the 42 inch RCP flow in the channel leading to the box culvert under Washington Street (design point #6). Basin A is the onsite basin which is broken into seven sub-basins, A1 through A7. The existing site consists of native vegetation. A1 consist of the majority of the development portion of the site including storage buildings and drive aisles, A2 is the north drive aisle which eventually enters A3 through a curb opening near the northern access point. A3 is the green space at the front of the site near Washington Street. Sub-basin A4 includes the main access point on the south eastern side of the site along with the main building parking area and the disturbed area added to the Qwest parking lot. A5 is the detention pond. A6 and A7 are areas outside the development area where flow will be undisturbed. More details and specifics will be explained in the drainage facility design portion of this report. DRAINAGE DESIGN CRITERIA The drainage plan is designed in accordance to the City of Thornton Standards and Specifications for the Design and Construction of Public Improvements, revised October 2012 and Urban Drainage and Flood Control District Criteria Manual Volume 1 and Criteria Manual Volume 2, revised April 2008. Procedures for estimating storm runoff are those described in the manuals above. Anderson and Hastings prepared a drainage study for the Qwest site titled Qwest Thornton Exchange Expansion which included the Self-Storage site. The east side of the site has many constraints including Washington Street, utilities along Washington Street, the gas regulator station, and converging drainage systems. The rainfall distribution values were found in table 400-1 of the City of Thornton Standards and Specifications. The rational method was used since the site area was less than 160 acres. Runoff values were determined for the 5-year initial storm and 100-year major storm event. Runoff coefficients were taken from tables RO-3 and RO-5 in the Urban Drainage and Flood Control District, weighting global values based on percentage of land use type. Detention volumes were determined along with the allowable release rates for both the 5-year and 100-year storms per Urban Drainage and Flood Control District spreadsheets which can be viewed in the appendix of this report. Bentley FlowMaster V8i was used to determine pipe capacity, channel capacity, pipe size, and normal depth in the pipe. The reports for these pipes can be found in the appendix of this report.

WETLAND PRESERVATOIN AND MITIGATION There is no evidence of any wetlands present on the site. DRAINAGE FACILITY DESIGN The 10-year and 100-year detention basin discharge through the outlet pipe will be 0.85 cfs and 4.88 cfs respectively. To determine these discharge rates Urban Drainage and Flood Control table SO-1 was used for Hydrologic Soil Group C for the on-site Platner loam soils found in the NRCS web soil survey. The site is currently undeveloped open space that is 2% impervious and therefore requires a 10-year and 100-year volume of 0.41 and 0.76 acre feet. respectively. The detention basin will be constructed with 4 to 1 maximum side slopes. Volume provided for water quality is 0.16 acre feet. An emergency outlet sized for twice the 100-year outlet rate will be notched into the berm on the northeast side of the basin. The emergency outlet will be armored with Type L rip-rap. Grading will be accomplished by having a ridge line along the north side of the buildings. Flow will travel south in the drive aisles between the buildings to the curb and gutter in the south access drive, eventually passing through a curb opening into the detention pond. The flow north of the buildings will travel east along the north access drive curb and gutter to a curb opening to the green space at the east side of the site. This flow will join with the flow from that green space and be piped to the detention pond. The main access at the southeast corner of the site will convey flow through a curb opening at the detention pond. Undisturbed areas along the north and south side of the property will continue their historical flow to the east. The site has a 5-year and 100-year runoff rate of 9.9 and 22.3 cfs respectively. This flow will follow the historical path, sheet flowing from west to east across the site. The northern flow will enter a curb opening just east of the first building. From there it will travel over grass to an area inlet and piped to the detention pond. Flow on the south side of the property will flow to a curb opening and enter the detention pond. Flow from Basin OS5 was determined to be 16.3 and 35.2 cfs for the 5-year and 100-year, respectively. This flow will be collected in a culvert opening on the west side of the property and piped along the north side of the property to the culvert under Washington Street. CONCULSIONS The drainage plan was designed in accordance with City of Thornton Standard and Specifications. Calculations for the determination of runoff rates and volumes are included in the appendix of this report. The calculations were performed in accordance to the Thornton Standards and procedures given in the UDFCD Manual. A detention basin is provided to limit the runoff from the developed site so that there will be no impact on the downstream drainage facilities.

REFERENCES Standards and Specifications for the Design and Construction of Public Improvements, City of Thornton, 2012 Edition Urban Storm Drainage Criteria Manual (Volumes 1 & 2), Urban Drainage and Flood Control District, Denver, Colorado, June 2001 (with current revisions) Phase III Drainage Report, Anderson & Hastings on behalf of Qwest, Denver, Colorado, June 2000

APPENDIX

603 Park Point Drive, Suite 100 Golden, CO 80401

Table A-2 Off-Site C Value Calculations Self-Storage Thornton, Colorado Global Parameters 1 total park/open % pave/build % % check composite Imp. Land Use % Imp. C 2 C 5 C 100 Basin OS1 22.64 2.60 11.49% 20.04 88.51% 88.74% Low Density Residential 35 0.25 0.33 0.57 Basin OS2 4.10 0.41 10.00% 3.69 90.00% 90.20% Medium Density Residential 50 0.34 0.40 0.60 Basin OS3 16.11 1.68 10.42% 14.43 89.58% 89.79% Multi-Family 75 0.54 0.58 0.71 BasinOS4 5.00 2.17 43.30% 2.84 56.70% 57.57% Parks/Open Space 2 0.04 0.15 0.50 Basin OS5 9.65 4.95 51.32% 4.70 48.68% 49.71% Pavement/Building 100 0.89 0.90 0.96 Basin A 4.98 4.98 100.00% 0.00 0.00% 2.00% Subbasin Total Area (acres) Land Use Area per Sub-Basin C Coefficient 2 Residential Parks/Open Space Pavement/Building Composite Imperviousness Low Density Medium Density Multi-Family % Check 2-year 5-year 100-year Area (acres) % Area (acres) % Area (acres) % Area (acres) % Area (acres) % 1 1.45 0 0.0% 0.00 0.0% 0 0.0% 0.15 10.0% 1.31 90.0% 100.00% 90% 0.81 0.83 0.91 2 1.04 0 0.0% 0.00 0.0% 0 0.0% 0.10 10.0% 0.94 90.0% 100.00% 90% 0.81 0.83 0.91 3 1.47 0 0.0% 0.00 0.0% 0 0.0% 0.74 50.0% 0.74 50.0% 100.00% 51% 0.47 0.53 0.73 4 1.86 0 0.0% 0.00 0.0% 0 0.0% 0.19 10.0% 1.67 90.0% 100.00% 90% 0.81 0.83 0.91 5 1.11 0 0.0% 0.00 0.0% 0 0.0% 0.11 10.0% 1.00 90.0% 100.00% 90% 0.81 0.83 0.91 6 1.88 0 0.0% 0.00 0.0% 0 0.0% 0.19 10.0% 1.69 90.0% 100.00% 90% 0.81 0.83 0.91 7 1.69 0 0.0% 0.00 0.0% 0 0.0% 0.17 10.0% 1.52 90.0% 100.00% 90% 0.81 0.83 0.91 8 0.90 0 0.0% 0.00 0.0% 0 0.0% 0.09 10.0% 0.81 90.0% 100.00% 90% 0.81 0.83 0.91 9 0.96 0 0.0% 0.00 0.0% 0 0.0% 0.10 10.0% 0.86 90.0% 100.00% 90% 0.81 0.83 0.91 10 2.51 0 0.0% 0.00 0.0% 0 0.0% 0.00 0.0% 2.51 100.0% 100.00% 100% 0.89 0.90 0.96 11 1.59 0 0.0% 0.00 0.0% 0 0.0% 0.16 10.0% 1.43 90.0% 100.00% 90% 0.81 0.83 0.91 12 2.80 0 0.0% 0.00 0.0% 0 0.0% 0.28 10.0% 2.52 90.0% 100.00% 90% 0.81 0.83 0.91 13 0.83 0 0.0% 0.00 0.0% 0 0.0% 0.08 10.0% 0.75 90.0% 100.00% 90% 0.81 0.83 0.91 14 1.82 0 0.0% 0.00 0.0% 0 0.0% 0.18 10.0% 1.64 90.0% 100.00% 90% 0.81 0.83 0.91 15 1.69 0 0.0% 0.00 0.0% 0 0.0% 0.17 10.0% 1.52 90.0% 100.00% 90% 0.81 0.83 0.91 16 0.91 0 0.0% 0.00 0.0% 0 0.0% 0.09 10.0% 0.82 90.0% 100.00% 90% 0.81 0.83 0.91 17 4.10 0 0.0% 0.00 0.0% 0 0.0% 0.41 10.0% 3.69 90.0% 100.00% 90% 0.81 0.83 0.91 18 1.51 0 0.0% 0.00 0.0% 0 0.0% 0.15 10.0% 1.36 90.0% 100.00% 90% 0.81 0.83 0.91 19 1.84 0 0.0% 0.00 0.0% 0 0.0% 0.18 10.0% 1.66 90.0% 100.00% 90% 0.81 0.83 0.91 20 3.08 0 0.0% 0.00 0.0% 0 0.0% 0.31 10.0% 2.77 90.0% 100.00% 90% 0.81 0.83 0.91 21 5.06 0 0.0% 0.00 0.0% 0 0.0% 0.51 10.0% 4.55 90.0% 100.00% 90% 0.81 0.83 0.91 22 5.09 0 0.0% 0.00 0.0% 0 0.0% 0.00 0.0% 5.09 100.0% 100.00% 100% 0.89 0.90 0.96 23 2.88 0 0.0% 0.00 0.0% 0 0.0% 0.86 30.0% 2.02 70.0% 100.00% 71% 0.64 0.68 0.82 24 4.43 0 0.0% 0.00 0.0% 0 0.0% 4.43 100.0% 0.00 0.0% 100.00% 2% 0.04 0.15 0.50 25 3.78 0 0.0% 0.00 0.0% 0 0.0% 0.95 25.0% 2.84 75.0% 100.00% 76% 0.68 0.71 0.85 26 1.22 0 0.0% 0.00 0.0% 0 0.0% 1.22 100.0% 0.00 0.0% 100.00% 2% 0.04 0.15 0.50 27 4.98 0 0.0% 0.00 0.0% 0 0.0% 4.98 100.0% 0.00 0.0% 100.00% 2% 0.04 0.15 0.50 Total 62.48 0.00 0.0% 0.00 0.0% 0.00 0.0% 4.35 7.0% 40.84 65.4% 72.33% 66% 0.58 0.60 0.66 1. From Table RO-3 and RO-5 in the UDFCD USDCM 2. C coefficients calculated by weighting global C values based on percentage of land use type.

Table A-3 Off-Site Rational Method Hydrologic Calculations Thornton Self-Storage Thornton, Colorado Sub-Basin Data C Values 2-year 5-year 100-year Time of Concentration, Tc Overland Time (ti) Travel Time (tt) Tc Tc Check Final Tc Intensity, I Peak Discharge, Q Design Pt. Basin ID Area C CA C CA C CA Length (300' max) Slope ti Length Slope Velocity tt tc=ti+tt Total length Tc = (l/180+10) Final Tc 2-year 5-year 100-year 2-year 5-year 100-year acres ft % min. ft % fps min min ft min min in/hr cfs 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 A 1 1.45 0.81 1.17 0.83 1.20 0.91 1.33 223 0.7% 8.5 280 0.7% 1.7 2.7 11.2 503 12.8 11.2 2.50 3.56 6.95 2.9 4.3 9.2 B 2 1.04 0.81 0.84 0.83 0.86 0.91 0.95 147 0.7% 6.9 285 0.7% 1.7 2.8 9.7 432 12.4 9.7 2.66 3.78 7.37 2.2 3.2 7.0 C 3 1.47 0.47 0.68 0.53 0.77 0.73 1.07 180 0.6% 16.8 300 0.6% 1.5 3.3 20.1 480 12.7 12.7 2.38 3.38 6.60 1.6 2.6 7.1 D 4 1.86 0.81 1.50 0.83 1.53 0.91 1.70 280 1.6% 7.2 300 1.6% 2.3 2.2 9.4 580 13.2 9.4 2.69 3.83 7.46 4.0 5.9 12.7 E 5 1.11 0.81 0.89 0.83 0.92 0.91 1.01 180 2.1% 5.3 285 2.1% 2.9 1.6 6.9 465 12.6 6.9 2.99 4.26 8.30 2.7 3.9 8.4 F 6 1.88 0.81 1.51 0.83 1.55 0.91 1.72 200 1.4% 6.4 275 1.4% 2.4 1.9 8.3 475 12.6 8.3 2.82 4.01 7.81 4.3 6.2 13.4 G 7 1.69 0.81 1.36 0.83 1.39 0.91 1.54 250 1.3% 7.3 300 1.3% 2.3 2.2 9.5 550 13.1 9.5 2.68 3.81 7.43 3.6 5.3 11.5 H 8 0.90 0.81 0.72 0.83 0.74 0.91 0.82 170 1.3% 6.0 230 1.3% 2.3 1.7 7.7 400 12.2 7.7 2.89 4.11 8.01 2.1 3.1 6.6 I 9 0.96 0.81 0.77 0.83 0.79 0.91 0.88 175 2.1% 5.2 240 2.1% 2.9 1.4 6.6 415 12.3 6.6 3.04 4.32 8.43 2.3 3.4 7.4 J 10 2.51 0.89 2.23 0.90 2.26 0.96 2.41 30 2.9% 1.4 1970 2.9% 3.2 10.3 11.7 2000 21.1 11.7 2.46 3.51 6.83 5.5 7.9 16.5 14.87 11.68 12.02 13.44 18.3 2.00 2.84 5.54 23.4 34.2 74.5 K 11 1.59 0.81 1.28 0.83 1.31 0.91 1.45 220 2.4% 5.6 250 2.4% 3.1 1.3 6.9 470 12.6 6.9 2.99 4.26 8.30 3.8 5.6 12.1 L 12 2.80 0.81 2.25 0.83 2.31 0.91 2.56 280 2.4% 6.3 250 2.4% 3.1 1.3 7.6 530 12.9 7.6 2.90 4.12 8.03 6.5 9.5 20.6 M 13 0.83 0.81 0.67 0.83 0.68 0.91 0.76 180 0.6% 8.2 53 0.6% 1.5 0.6 8.7 233 11.3 8.7 2.76 3.93 7.66 1.8 2.7 5.8 5.22 4.20 4.31 4.77 8.7 2.77 3.94 7.67 11.6 17.0 36.6 N 14 1.82 0.81 1.47 0.83 1.50 0.91 1.66 270 1.8% 6.8 225 1.8% 2.5 1.5 8.3 495 12.8 8.3 2.81 4.00 7.79 4.1 6.0 13.0 O 15 1.69 0.81 1.36 0.83 1.39 0.91 1.54 300 1.8% 7.2 270 1.8% 2.5 1.8 9.0 570 13.2 9.0 2.73 3.89 7.58 3.7 5.4 11.7 P 16 0.91 0.81 0.73 0.83 0.75 0.91 0.83 30 0.3% 4.0 400 0.3% 1.8 3.7 7.7 430 12.4 7.7 2.89 4.12 8.03 2.1 3.1 6.7 19.29 15.24 15.66 17.48 23.3 1.76 2.50 4.87 26.8 39.2 85.2 Q 17 4.10 0.81 3.30 0.83 3.38 0.91 3.75 300 1.0% 8.7 250 1.0% 2.0 2.1 10.8 550 13.1 10.8 2.54 3.62 7.05 8.4 12.2 26.4 R 18 1.51 0.81 1.22 0.83 1.25 0.91 1.38 210 1.6% 6.3 300 1.6% 2.3 2.2 8.4 510 12.8 8.4 2.80 3.98 7.75 3.4 5.0 10.7 S 19 1.84 0.81 1.48 0.83 1.52 0.91 1.68 19 2.0% 1.7 1150 2.0% 2.8 6.8 8.6 1169 16.5 8.6 2.78 3.95 7.71 4.1 6.0 13.0 22.64 17.94 18.43 20.54 28.3 1.57 2.24 4.37 28.2 41.3 89.7 T 20 3.08 0.81 2.48 0.83 2.54 0.91 2.82 265 1.6% 7.0 685 1.6% 2.3 5.0 12.0 950 15.3 12.0 2.44 3.47 6.76 6.0 8.8 19.0 U 21 5.06 0.81 4.07 0.83 4.17 0.91 4.62 175 0.7% 7.4 450 0.7% 1.7 4.4 11.8 625 13.5 11.8 2.45 3.49 6.80 10.0 14.6 31.5 V 22 5.09 0.89 4.53 0.90 4.58 0.96 4.89 30 1.6% 1.7 1875 2.0% 2.3 13.6 15.3 1905 20.6 15.3 2.18 3.10 6.05 9.9 14.2 29.6 W 23 2.88 0.64 1.83 0.68 1.94 0.82 2.37 280 2.5% 9.6 280 2.5% 3.1 1.5 11.1 560 13.1 11.1 2.51 3.58 6.97 4.6 7.0 16.5 16.11 12.91 13.24 14.69 28.2 41.1 88.9 X 24 4.43 0.04 0.18 0.15 0.66 0.50 2.22 300 1.4% 27.0 720 3.5% 1.2 10.0 37.0 1020 15.7 15.7 2.16 3.07 5.98 0.4 2.0 13.2 9.65 4.38 4.97 6.99 15.7 2.16 3.07 5.98 9.4 15.3 41.8 site 27 4.98 0.04 0.20 0.15 0.75 0.50 2.49 50 2.2% 9.5 625 2.2% 1.0 10.4 19.9 675 13.8 13.8 2.29 3.26 6.36 0.5 2.4 15.8 Y 25 3.78 0.68 2.56 0.71 2.69 0.85 3.19 140 3.2% 5.7 485 3.2% 3.5 2.3 8.0 625 13.5 8.0 2.85 4.05 7.90 7.3 10.9 25.2 Z 26 1.22 0.04 0.05 0.15 0.18 0.50 0.61 120 0.0% 105.0 275 1.0% 0.7 6.5 111.5 395 12.2 12.2 2.42 3.44 6.71 0.1 0.6 4.1 5.00 2.61 2.88 3.80 12.2 2.42 3.44 6.71 6.3 9.9 25.5 Total 62.48 41.34 43.64 52.26 29.4 1.54 2.19 4.27 63.6 95.6 223.1 Thornton Self-Storage Offsite Hydrology 06082015.xls Q Peak 1 of 1

WASHINGTON STREET 48" RCP EX. 18" RCP 54" RCP 603 Park Point Drive, Suite 100 Golden, CO 80401

Table A-2 On-Site C Value Calculations Self-Storage Thornton, Colorado Global Parameters 1 Land Use % Imp. C 2 C 5 C 100 Low Density Residential 35 0.25 0.33 0.57 Medium Density Residential 50 0.34 0.40 0.60 Multi-Family 75 0.54 0.58 0.71 Parks/Open Space 2 0.04 0.15 0.50 Pavement/Building 100 0.89 0.90 0.96 Subbasin Land Use Area per Sub-Basin C Coefficient 2 Total Area Residential Parks/Open Space Pavement/Building Composite Imperviousness (acres) Low Density Medium Density Multi-Family % Check 2-year 5-year 100-year Area (acres) % Area (acres) % Area (acres) % Area (acres) % Area (acres) % A1 3.31 0.00 0.0% 0.00 0.0% 0 0.0% 0.00 0.0% 3.31 100.0% 100.00% 100% 0.89 0.90 0.96 A2 0.21 0.00 0.0% 0.00 0.0% 0 0.0% 0.00 0.0% 0.21 100.0% 100.00% 100% 0.89 0.90 0.96 A3 0.58 0.00 0.0% 0.00 0.0% 0 0.0% 0.57 98.3% 0.01 1.7% 100.00% 4% 0.05 0.16 0.51 A4 0.32 0.00 0.0% 0.00 0.0% 0 0.0% 0.00 0.0% 0.32 100.0% 100.00% 100% 0.89 0.90 0.96 A5 0.38 0.00 0.0% 0.00 0.0% 0 0.0% 0.38 100.0% 0.00 0.0% 100.00% 2% 0.04 0.15 0.50 A6 0.12 0.00 0.0% 0.00 0.0% 0 0.0% 0.12 100.0% 0.00 0.0% 100.00% 2% 0.04 0.15 0.50 A7 0.18 0.00 0.0% 0.00 0.0% 0 0.0% 0.18 100.0% 0.00 0.0% 100.00% 2% 0.04 0.15 0.50 Total 4.88 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.95 19.5% 3.93 80.5% 100.00% 81% 0.72 0.75 0.87 1. From Table RO-3 and RO-5 in the UDFCD USDCM 2. C coefficients calculated by weighting global C values based on percentage of land use type.

Table A-3 On-Site Rational Method Hydrologic Calculations Thornton Self-Storage Thornton, Colorado Sub-Basin Data C Values 2-year 5-year 100-year Time of Concentration, Tc Overland Time (ti) Travel Time (tt) Tc Tc Check Final Tc Intensity, I Peak Discharge, Q Design Pt. Basin ID Area C CA C CA C CA Length (300' max) Slope Length Slope ti tt acres ft % min. ft % fps min min ft min min in/hr cfs 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 Velocity tc=ti+tt Total length Tc = (l/180+10) Final Tc 2-year 5-year 100-year 2-year 5-year 100-year 1 A1 3.31 0.89 2.95 0.90 2.98 0.96 3.18 31 1.5% 1.8 276 1.5% 1.7 2.7 4.5 307 11.7 7.8 2.88 4.09 7.98 8.5 12.2 25.3 2 A2 0.21 0.89 0.19 0.90 0.19 0.96 0.20 8 1.0% 1.0 485 0.8% 2.7 3.0 4.0 493 12.7 4.0 3.47 4.93 9.62 0.6 0.9 1.9 2 A3 0.58 0.05 0.03 0.16 0.09 0.51 0.29 20 1.0% 7.7 205 1.0% 3.7 0.9 8.6 225 11.3 8.6 2.78 3.95 7.70 0.1 0.4 2.3 0.79 0.22 0.28 0.50 12.6 2.38 3.39 6.60 0.5 1.0 3.3 3 A4 0.32 0.89 0.28 0.90 0.29 0.96 0.31 12 1.0% 1.3 234 1.0% 4.7 0.8 2.1 246 11.4 2.1 3.90 5.54 10.80 1.1 1.6 3.3 6 A5 0.38 0.04 0.02 0.15 0.06 0.50 0.19 24 4.0% 5.4 109 1.0% 6.7 0.3 5.6 133 10.7 5.6 3.18 4.53 8.83 0.0 0.3 1.7 4 A6 0.12 0.04 0.00 0.15 0.02 0.50 0.06 15 1.0% 6.7 652 1.3% 5.7 1.9 8.7 667 13.7 8.7 2.77 3.94 7.69 0.0 0.1 0.5 5 A7 0.18 0.04 0.01 0.15 0.03 0.50 0.09 27 1.5% 7.9 573 1.3% 6.7 1.4 9.3 600 13.3 9.3 2.70 3.83 7.47 0.0 0.1 0.7 TOTAL 5.89 3.70 3.94 4.82 7.8 2.88 4.09 7.98 10.6 16.1 38.4 Thornton Self-Storage Site Hydrology 08112015.xls Q Peak 2 of 2

DETENTION VOLUME BY THE MODIFIED FAA METHOD (See USDCM Volume 2 Storage Chapter for description of method) Project: THORNTON SELF-STORAGE Basin ID: ON SITE FLOW Design Information (Input): Design Information (Input): Catchment Drainage Imperviousness I a = 81.00 percent Catchment Drainage Imperviousness I a = 81.00 percent Catchment Drainage Area A = 4.880 acres Catchment Drainage Area A = 4.880 acres Predevelopment NRCS Soil Group Type = B A, B, C, or D Predevelopment NRCS Soil Group Type = B A, B, C, or D Return Period for Detention Control T = 10 years (2, 5, 10, 25, 50, or 100) Return Period for Detention Control T = 100 years (2, 5, 10, 25, 50, or 100) Time of Concentration of Watershed Tc = 13 minutes Time of Concentration of Watershed Tc = 13 minutes Allowable Unit Release Rate q = 0.23 cfs/acre Allowable Unit Release Rate q = 1.00 cfs/acre One-hour Precipitation P 1 = 0.97 inches One-hour Precipitation P 1 = 2.69 inches Design Rainfall IDF Formula i = C 1* P 1/(C 2+T c)^c 3 Design Rainfall IDF Formula i = C 1* P 1/(C 2+T c)^c 3 Coefficient One C 1 = 28.50 Coefficient One C 1 = 28.50 Coefficient Two C 2 = 10 Coefficient Two C 2 = 10 Coefficient Three C 3 = 0.789 Coefficient Three C 3 = 0.789 Determination of Average Outflow from the Basin (Calculated): (For catchments less than 160 acres only. For larger catchments, use hydrograph routing method) (NOTE: for catchments larger than 90 acres, CUHP hydrograph and routing are recommended) Determination of MINOR Detention Volume Using Modified FAA Method Determination of MAJOR Detention Volume Using Modified FAA Method Determination of Average Outflow from the Basin (Calculated): Runoff Coefficient C = 0.64 Runoff Coefficient C = 0.71 Inflow Peak Runoff Qp-in = 7.38 cfs Inflow Peak Runoff Qp-in = 22.69 cfs Allowable Peak Outflow Rate Qp-out = 1.12 cfs Allowable Peak Outflow Rate Qp-out = 4.88 cfs Mod. FAA Minor Storage Volume = 8,912 cubic feet Mod. FAA Major Storage Volume = 23,062 cubic feet Mod. FAA Minor Storage Volume = 0.205 acre-ft Mod. FAA Major Storage Volume = 0.529 acre-ft 10 <- Enter Rainfall Duration Incremental Increase Value Here (e.g. 5 for 5-Minutes) Rainfall Rainfall Inflow Adjustment Average Outflow Storage Rainfall Rainfall Inflow Adjustment Average Outflow Storage Duration Intensity Volume Factor Outflow Volume Volume Duration Intensity Volume Factor Outflow Volume Volume minutes inches / hr cubic feet "m" cfs cubic feet cubic feet minutes inches / hr cubic feet "m" cfs cubic feet cubic feet (input) (output) (output) (output) (output) (output) (output) (input) (output) (output) (output) (output) (output) (output) 0 0.00 0 0.00 0.00 0 0 0 0.00 0 0.00 0.00 0 0 10 2.60 4,874 1.00 1.12 673 4,200 10 7.21 14,994 1.00 4.88 2,928 12,066 20 1.89 7,079 0.82 0.91 1,098 5,981 20 5.24 21,777 0.82 3.98 4,773 17,005 30 1.51 8,462 0.71 0.80 1,434 7,027 30 4.17 26,033 0.71 3.46 6,237 19,796 40 1.26 9,461 0.66 0.74 1,771 7,690 40 3.50 29,107 0.66 3.21 7,701 21,406 50 1.09 10,242 0.63 0.70 2,108 8,134 50 3.03 31,509 0.63 3.05 9,165 22,344 60 0.97 10,883 0.61 0.68 2,445 8,438 60 2.68 33,481 0.61 2.95 10,629 22,852 70 0.87 11,427 0.59 0.66 2,781 8,646 70 2.42 35,155 0.59 2.88 12,093 23,062 80 0.79 11,900 0.58 0.65 3,118 8,782 80 2.20 36,612 0.58 2.82 13,557 23,055 90 0.73 12,320 0.57 0.64 3,455 8,865 90 2.03 37,903 0.57 2.78 15,021 22,882 100 0.68 12,697 0.56 0.63 3,791 8,906 100 1.88 39,063 0.56 2.75 16,485 22,579 110 0.63 13,040 0.56 0.63 4,128 8,912 110 1.75 40,119 0.56 2.72 17,949 22,170 120 0.59 13,355 0.55 0.62 4,465 8,890 120 1.65 41,087 0.55 2.70 19,413 21,675 130 0.56 13,646 0.55 0.62 4,802 8,845 130 1.55 41,983 0.55 2.68 20,877 21,106 140 0.53 13,917 0.55 0.61 5,138 8,779 140 1.47 42,817 0.55 2.66 22,341 20,477 150 0.50 14,171 0.54 0.61 5,475 8,696 150 1.40 43,598 0.54 2.64 23,805 19,793 160 0.48 14,410 0.54 0.61 5,812 8,598 160 1.33 44,333 0.54 2.63 25,269 19,064 170 0.46 14,635 0.54 0.60 6,149 8,487 170 1.27 45,026 0.54 2.62 26,733 18,294 180 0.44 14,849 0.54 0.60 6,485 8,364 180 1.22 45,684 0.54 2.61 28,197 17,487 190 0.42 15,052 0.53 0.60 6,822 8,231 190 1.17 46,309 0.53 2.60 29,661 16,649 200 0.41 15,246 0.53 0.60 7,159 8,088 200 1.13 46,906 0.53 2.59 31,125 15,781 210 0.39 15,432 0.53 0.59 7,495 7,936 210 1.09 47,476 0.53 2.59 32,589 14,887 220 0.38 15,609 0.53 0.59 7,832 7,777 220 1.05 48,023 0.53 2.58 34,053 13,970 230 0.37 15,780 0.53 0.59 8,169 7,611 230 1.02 48,548 0.53 2.57 35,517 13,031 240 0.35 15,944 0.53 0.59 8,506 7,439 240 0.98 49,053 0.53 2.57 36,981 12,072 250 0.34 16,103 0.53 0.59 8,842 7,260 250 0.95 49,540 0.53 2.56 38,445 11,095 260 0.33 16,255 0.52 0.59 9,179 7,076 260 0.93 50,010 0.52 2.56 39,909 10,101 270 0.32 16,403 0.52 0.59 9,516 6,887 270 0.90 50,464 0.52 2.55 41,373 9,091 280 0.32 16,546 0.52 0.59 9,852 6,694 280 0.87 50,904 0.52 2.55 42,837 8,067 290 0.31 16,685 0.52 0.59 10,189 6,495 290 0.85 51,331 0.52 2.55 44,301 7,030 300 0.30 16,819 0.52 0.58 10,526 6,293 300 0.83 51,744 0.52 2.54 45,765 5,980 310 0.29 16,950 0.52 0.58 10,863 6,087 310 0.81 52,146 0.52 2.54 47,229 4,918 320 0.28 17,077 0.52 0.58 11,199 5,878 320 0.79 52,537 0.52 2.54 48,693 3,845 330 0.28 17,201 0.52 0.58 11,536 5,665 330 0.77 52,918 0.52 2.53 50,157 2,761 340 0.27 17,321 0.52 0.58 11,873 5,448 340 0.75 53,289 0.52 2.53 51,621 1,668 350 0.27 17,439 0.52 0.58 12,209 5,229 350 0.74 53,650 0.52 2.53 53,085 566 360 0.26 17,553 0.52 0.58 12,546 5,007 360 0.72 54,003 0.52 2.53 54,549-546 370 0.25 17,665 0.52 0.58 12,883 4,782 370 0.71 54,347 0.52 2.52 56,013-1,665 380 0.25 17,775 0.52 0.58 13,220 4,555 380 0.69 54,684 0.52 2.52 57,477-2,793 390 0.24 17,882 0.52 0.58 13,556 4,325 390 0.68 55,013 0.52 2.52 58,941-3,928 400 0.24 17,986 0.52 0.58 13,893 4,093 400 0.67 55,335 0.52 2.52 60,405-5,070 410 0.24 18,089 0.52 0.58 14,230 3,859 410 0.65 55,650 0.52 2.51 61,869-6,218 420 0.23 18,189 0.52 0.58 14,567 3,623 420 0.64 55,959 0.52 2.51 63,333-7,374 430 0.23 18,287 0.51 0.58 14,903 3,384 430 0.63 56,261 0.51 2.51 64,797-8,535 440 0.22 18,384 0.51 0.58 15,240 3,144 440 0.62 56,558 0.51 2.51 66,261-9,703 450 0.22 18,478 0.51 0.58 15,577 2,902 450 0.61 56,849 0.51 2.51 67,725-10,876 460 0.22 18,571 0.51 0.58 15,913 2,658 460 0.60 57,135 0.51 2.51 69,189-12,054 470 0.21 18,662 0.51 0.58 16,250 2,412 470 0.59 57,415 0.51 2.51 70,653-13,238 480 0.21 18,752 0.51 0.58 16,587 2,165 480 0.58 57,690 0.51 2.50 72,117-14,426 490 0.21 18,840 0.51 0.58 16,924 1,916 490 0.57 57,961 0.51 2.50 73,581-15,620 500 0.20 18,926 0.51 0.58 17,260 1,666 500 0.56 58,227 0.51 2.50 75,045-16,818 510 0.20 19,011 0.51 0.58 17,597 1,414 510 0.55 58,488 0.51 2.50 76,509-18,020 520 0.20 19,095 0.51 0.57 17,934 1,161 520 0.54 58,746 0.51 2.50 77,973-19,227 530 0.19 19,177 0.51 0.57 18,270 907 530 0.54 58,999 0.51 2.50 79,437-20,438 540 0.19 19,258 0.51 0.57 18,607 651 540 0.53 59,248 0.51 2.50 80,901-21,653 550 0.19 19,338 0.51 0.57 18,944 394 550 0.52 59,493 0.51 2.50 82,365-22,871 560 0.19 19,416 0.51 0.57 19,281 136 560 0.51 59,735 0.51 2.49 83,829-24,094 570 0.18 19,494 0.51 0.57 19,617-123 570 0.51 59,973 0.51 2.49 85,293-25,320 580 0.18 19,570 0.51 0.57 19,954-384 580 0.50 60,208 0.51 2.49 86,757-26,549 590 0.18 19,645 0.51 0.57 20,291-645 590 0.49 60,439 0.51 2.49 88,221-27,782 600 0.18 19,719 0.51 0.57 20,627-908 600 0.49 60,667 0.51 2.49 89,685-29,018 Mod. FAA Minor Storage Volume (cubic ft.) = 8,912 Mod. FAA Major Storage Volume (cubic ft.) = 23,062 Mod. FAA Minor Storage Volume (acre-ft.) = 0.2046 Mod. FAA Major Storage Volume (acre-ft.) = 0.5294 UDFCD DETENTION VOLUME ESTIMATING WORKBOOK Version 2.2, Released January 2010 Modified FAA Method.xls, Modified FAA 8/13/2015, 3:54 PM

DETENTION VOLUME BY THE MODIFIED FAA METHOD (See USDCM Volume 2 Storage Chapter for description of method) Project: THORNTON SELF-STORAGE Basin ID: ON SITE FLOW Inflow and Outflow Volumes vs. Rainfall Duration 100,000 80,000 60,000 Volume (Cubic Feet) 40,000 20,000 0 0 100 200 300 400 500 600 700-20,000-40,000 Duration (Minutes) Minor Storm Inflow Volume Minor Storm Outflow Volume Minor Storm Storage Volume Major Storm Inflow Volume Major Storm Outflow Volume Major Storm Storage Volume UDFCD DETENTION VOLUME ESTIMATING WORKBOOK Version 2.2, Released January 2010 Modified FAA Method.xls, Modified FAA 8/13/2015, 3:54 PM

Detention Summary Thornton Self-Storage Detention Basin Basin 1 Contributing Area, Acres 4.88 Bottom Elevation 5330 Overflow Elevation 5335 Basin Depth, ft. 5.0 WQCV, cf 5,928 10-year WSE 5332.0 10-Year Depth, ft. 2.0 10-year Volume, cf 16,156 10-year Peak Outflow, cfs 1.12 100-year WSE 5334.0 100-Year Depth, ft. 4.0 100-year Volume, cf 36,922 100-year Peak Outflow, cfs 4.88 Total Provided: WQCV, cf 7,024 10-Year, cf 18,105 100-Year, cf 33,569 Total Required: WQCV, cf 5,928 10-Year, cf 15,954 100-Year, cf 30,114

INLET IN A SUMP OR SAG LOCATION Project = Inlet ID = THORNTON SELF-STORAGE WASHINGTON SUMP H-Curb W W P H-Vert Lo (C) Wo Lo (G) Design Information (Input) MINOR MAJOR Type of Inlet Inlet Type = CDOT Type R Curb Opening Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') a local = 3.00 3.00 inches Number of Unit Inlets (Grate or Curb Opening) No = 1 1 Water Depth at Flowline (outside of local depression) Ponding Depth = 6.0 6.2 inches Grate Information MINOR MAJOR Override Depths Length of a Unit Grate L o (G) = N/A N/A feet Width of a Unit Grate W o = N/A N/A feet Area Opening Ratio for a Grate (typical values 0.15-0.90) A ratio = N/A N/A Clogging Factor for a Single Grate (typical value 0.50-0.70) C f (G) = N/A N/A Grate Weir Coefficient (typical value 2.15-3.60) C w (G) = N/A N/A Grate Orifice Coefficient (typical value 0.60-0.80) C o (G) = N/A N/A Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening L o (C) = 15.00 15.00 feet Height of Vertical Curb Opening in Inches H vert = 6.00 6.00 inches Height of Curb Orifice Throat in Inches H throat = 6.00 6.00 inches Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 degrees Side Width for Depression Pan (typically the gutter width of 2 feet) W p = 2.00 2.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10) C f (C) = 0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7) C w (C) = 3.60 3.60 Curb Opening Orifice Coefficient (typical value 0.60-0.70) C o (C) = 0.67 0.67 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition) Q a = 9.7 10.6 cfs WARNING: Inlet Capacity less than Q Peak for Minor and Major Storms Q PEAK REQUIRED = 51.0 114.4 cfs Washington 100yr Sump Inlet.xlsm, Inlet In Sump 8/14/2015, 1:16 PM

Worksheet for commercial site 100yr inlet pipe Project Description Friction Method Solve For Manning Formula Full Flow Diameter Input Data Roughness Coefficient 0.013 Channel Slope 1.00000 % Normal Depth 2.40 ft Diameter 28.75 in Discharge 36.60 ft³/s Results Diameter 28.75 in Normal Depth 2.40 ft Flow Area 4.51 ft² Wetted Perimeter 7.53 ft Hydraulic Radius 0.60 ft Top Width 0.00 ft Critical Depth 2.05 ft Percent Full 100.0 % Critical Slope 0.00929 ft/ft Velocity 8.12 ft/s Velocity Head 1.02 ft Specific Energy 3.42 ft Froude Number 0.00 Maximum Discharge 39.37 ft³/s Discharge Full 36.60 ft³/s Slope Full 0.01000 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % 8/14/2015 11:05:04 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2

Worksheet for commercial site 100yr inlet pipe GVF Output Data Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 2.40 ft Critical Depth 2.05 ft Channel Slope 1.00000 % Critical Slope 0.00929 ft/ft 8/14/2015 11:05:04 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2

Worksheet for commercial site 5yr inlet pipe Project Description Friction Method Solve For Manning Formula Full Flow Diameter Input Data Roughness Coefficient 0.013 Channel Slope 1.00000 % Normal Depth 1.79 ft Diameter 21.51 in Discharge 16.90 ft³/s Results Diameter 21.51 in Normal Depth 1.79 ft Flow Area 2.52 ft² Wetted Perimeter 5.63 ft Hydraulic Radius 0.45 ft Top Width 0.00 ft Critical Depth 1.51 ft Percent Full 100.0 % Critical Slope 0.00957 ft/ft Velocity 6.69 ft/s Velocity Head 0.70 ft Specific Energy 2.49 ft Froude Number 0.00 Maximum Discharge 18.18 ft³/s Discharge Full 16.90 ft³/s Slope Full 0.01000 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % 8/14/2015 11:24:29 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2

Worksheet for commercial site 5yr inlet pipe GVF Output Data Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.79 ft Critical Depth 1.51 ft Channel Slope 1.00000 % Critical Slope 0.00957 ft/ft 8/14/2015 11:24:29 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2

Project Description Worksheet for 5yr Penn Plus 100yr Commercial Friction Method Solve For Manning Formula Full Flow Diameter Input Data Roughness Coefficient 0.013 Channel Slope 0.52000 % Normal Depth 3.49 ft Diameter 41.86 in Discharge 70.80 ft³/s Results Diameter 41.86 in Normal Depth 3.49 ft Flow Area 9.56 ft² Wetted Perimeter 10.96 ft Hydraulic Radius 0.87 ft Top Width 0.00 ft Critical Depth 2.64 ft Percent Full 100.0 % Critical Slope 0.00613 ft/ft Velocity 7.41 ft/s Velocity Head 0.85 ft Specific Energy 4.34 ft Froude Number 0.00 Maximum Discharge 76.16 ft³/s Discharge Full 70.80 ft³/s Slope Full 0.00520 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % 8/14/2015 11:02:29 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2

Worksheet for 5yr Penn Plus 100yr Commercial GVF Output Data Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 3.49 ft Critical Depth 2.64 ft Channel Slope 0.52000 % Critical Slope 0.00613 ft/ft 8/14/2015 11:02:29 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2

Project Description Worksheet for 5yr Penn Plus 5yr Commercial Friction Method Solve For Manning Formula Full Flow Diameter Input Data Roughness Coefficient 0.013 Channel Slope 0.52000 % Normal Depth 3.09 ft Diameter 37.04 in Discharge 51.10 ft³/s Results Diameter 37.04 in Normal Depth 3.09 ft Flow Area 7.48 ft² Wetted Perimeter 9.70 ft Hydraulic Radius 0.77 ft Top Width 0.00 ft Critical Depth 2.31 ft Percent Full 100.0 % Critical Slope 0.00627 ft/ft Velocity 6.83 ft/s Velocity Head 0.72 ft Specific Energy 3.81 ft Froude Number 0.00 Maximum Discharge 54.97 ft³/s Discharge Full 51.10 ft³/s Slope Full 0.00520 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % 8/14/2015 11:18:24 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2

Worksheet for 5yr Penn Plus 5yr Commercial GVF Output Data Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 3.09 ft Critical Depth 2.31 ft Channel Slope 0.52000 % Critical Slope 0.00627 ft/ft 8/14/2015 11:18:24 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2

Worksheet for 5yr Penn 100yr Com 5yr SNL Project Description Friction Method Solve For Manning Formula Full Flow Diameter Input Data Roughness Coefficient 0.013 Channel Slope 0.56000 % Normal Depth 3.99 ft Diameter 47.85 in Discharge 106.60 ft³/s Results Diameter 47.85 in Normal Depth 3.99 ft Flow Area 12.49 ft² Wetted Perimeter 12.53 ft Hydraulic Radius 1.00 ft Top Width 0.00 ft Critical Depth 3.13 ft Percent Full 100.0 % Critical Slope 0.00611 ft/ft Velocity 8.54 ft/s Velocity Head 1.13 ft Specific Energy 5.12 ft Froude Number 0.00 Maximum Discharge 114.67 ft³/s Discharge Full 106.60 ft³/s Slope Full 0.00560 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % 8/14/2015 11:03:31 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2

Worksheet for 5yr Penn 100yr Com 5yr SNL GVF Output Data Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 3.99 ft Critical Depth 3.13 ft Channel Slope 0.56000 % Critical Slope 0.00611 ft/ft 8/14/2015 11:03:31 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2

Worksheet for 5yr Penn 5yr Com 5yr SNL Project Description Friction Method Solve For Manning Formula Full Flow Diameter Input Data Roughness Coefficient 0.013 Channel Slope 0.56000 % Normal Depth 3.75 ft Diameter 44.96 in Discharge 90.30 ft³/s Results Diameter 44.96 in Normal Depth 3.75 ft Flow Area 11.03 ft² Wetted Perimeter 11.77 ft Hydraulic Radius 0.94 ft Top Width 0.00 ft Critical Depth 2.92 ft Percent Full 100.0 % Critical Slope 0.00617 ft/ft Velocity 8.19 ft/s Velocity Head 1.04 ft Specific Energy 4.79 ft Froude Number 0.00 Maximum Discharge 97.14 ft³/s Discharge Full 90.30 ft³/s Slope Full 0.00560 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % 8/14/2015 11:19:27 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2

Worksheet for 5yr Penn 5yr Com 5yr SNL GVF Output Data Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 3.75 ft Critical Depth 2.92 ft Channel Slope 0.56000 % Critical Slope 0.00617 ft/ft 8/14/2015 11:19:27 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2

Worksheet for outfall pipe to culvert 100yr Project Description Friction Method Solve For Manning Formula Full Flow Diameter Input Data Roughness Coefficient 0.013 Channel Slope 0.50000 % Normal Depth 4.13 ft Diameter 49.58 in Discharge 110.70 ft³/s Results Diameter 49.58 in Normal Depth 4.13 ft Flow Area 13.40 ft² Wetted Perimeter 12.98 ft Hydraulic Radius 1.03 ft Top Width 0.00 ft Critical Depth 3.16 ft Percent Full 100.0 % Critical Slope 0.00574 ft/ft Velocity 8.26 ft/s Velocity Head 1.06 ft Specific Energy 5.19 ft Froude Number 0.00 Maximum Discharge 119.08 ft³/s Discharge Full 110.70 ft³/s Slope Full 0.00500 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % 8/14/2015 11:04:08 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2

Worksheet for outfall pipe to culvert 100yr GVF Output Data Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 4.13 ft Critical Depth 3.16 ft Channel Slope 0.50000 % Critical Slope 0.00574 ft/ft 8/14/2015 11:04:08 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2

Worksheet for outfall pipe to culvert 5yr Project Description Friction Method Solve For Manning Formula Full Flow Diameter Input Data Roughness Coefficient 0.013 Channel Slope 0.50000 % Normal Depth 4.01 ft Diameter 48.16 in Discharge 102.50 ft³/s Results Diameter 48.16 in Normal Depth 4.01 ft Flow Area 12.65 ft² Wetted Perimeter 12.61 ft Hydraulic Radius 1.00 ft Top Width 0.00 ft Critical Depth 3.06 ft Percent Full 100.0 % Critical Slope 0.00577 ft/ft Velocity 8.10 ft/s Velocity Head 1.02 ft Specific Energy 5.03 ft Froude Number 0.00 Maximum Discharge 110.24 ft³/s Discharge Full 102.48 ft³/s Slope Full 0.00500 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % 8/14/2015 11:23:40 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2

Worksheet for outfall pipe to culvert 5yr GVF Output Data Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 4.01 ft Critical Depth 3.06 ft Channel Slope 0.50000 % Critical Slope 0.00577 ft/ft 8/14/2015 11:23:40 AM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2

Cross Section for washington sump xsection Project Description Friction Method Solve For Manning Formula Normal Depth Input Data Channel Slope 1.50000 % Normal Depth 1.50 ft Discharge 225.00 ft³/s Cross Section Image 8/14/2015 12:28:31 PM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1

Cross Section for washington sump xsection minus culvert capcity Project Description Friction Method Solve For Manning Formula Normal Depth Input Data Channel Slope 1.50000 % Normal Depth 1.16 ft Discharge 86.00 ft³/s Cross Section Image 8/14/2015 12:30:19 PM Bentley Systems, Inc. Haestad Methods Solution Bentley Center FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1