9_26-09_HAR892022C_ H&H Report.pdf

STORM WATER CALCULATIONS

For:

HAR892022C Nutrient Reduction Wetland Iowa Department of Agriculture and Land Stewardship

IOWA FALLS, Iowa

S-H PROJECT # 2142204310

July 8th, 2026

I hereby certify that the portion of this engineering document was prepared by me or under my direct personal supervision. I am a duly licensed Professional Engineer under the laws of the State of Iowa.

Signature: ____________________________________________

Name: Dan Jensen, P.E. .

Date: _________________________

My license renewal date is December 31, 2027.

Pages, sheets, or divisions covered by this certification: ________ _All Sheets

Prepared by:

4125 Westown Parkway, Suite 100 – West Des Moines, Iowa 50266

(515) 223-8104

07/08/2026

TABLE OF CONTENTS

1.) Project Summary

2.) Drainage Area Map

3.) Soil Map/Land Characteristics

4.) Principal Spillway Calculations

5.) Geotechnical Report

6.) Specifications

PROJECT SUMMARY

GENERAL

The proposed work includes construction of a wetland to the southeast of Iowa Falls, IA. The location can be more specifically described as the SW ¼ of Section 22, Township 89 North, Range 20 West of the Fifth Principal meridian, Hardin County, Iowa. A dam will be constructed to impound water for the wetland. A drawdown structure on the dam will allow for pool elevation control.

DESIGN STANDARDS, ANALYSIS, AND ASSUMPTIONS

The design procedures and guidelines were obtained from the following resources:

1. “National Engineering Handbook 4 – Hydrology”

2. “NRCS Practice Standard 656, 378, & 410” (as applicable)

DESIGN CRITERIA AND GUIDELINES

IOWA DNR DAM SAFETY

The structure size was reviewed for applicability of Iowa Administrative Code Chapter 73. The thresholds are primarily based on both dam height and water storage volumes. The height of a dam is defined as the vertical distance from the top of the dam to the lowest elevation at the downstream toe of the dam, typically the streambed.

The thresholds for when a Flood Plain Permit from the DNR is required are outlined in 567 Iowa Administrative Code Chapter 73.3 and are listed below with commentary for the HAR892022C Wetland:

Any dam with a height of at least 25 feet and a storage volume of at least 15 acre-ft

The storage at normal water level is 3.5 ac-ft The embankment height is 10 feet.

Any dam with a storage at the top of dam of at least 50 acre-ft and a height of at least 6 feet.

The storage at the top of dam is 34.9 ac-ft The embankment height is 10 feet.

Any high hazard dam (see dam classifications).

Structures located in areas where damages from a failure would be limited to loss of the dam, loss of livestock, damages to farm out-buildings, agricultural lands, and lesser used roads, and where loss of human life is considered unlikely. Therefore, the structure shall be classified as low hazard

An Iowa DNR Dam Safety or Floodplain Permit is not required for this project.

WATER CONTROL STRUCTURE

The water control structure is a 24” dual wall HDPE riser equipped with stop logs for water elevation control.

PRINCIPAL SPILLWAY AND WATER CONTROL STRUCTURE

The principal spillway structure is a 48” concrete box riser (modified SW-302) equipped with stop logs for water elevation control. A 36’’ RCP will enter the structure from the pool area and will exit the manhole structure and daylight downstream of the principal spillway into riprap and existing pond. The stop logs will allow for control of the water level and draining of the wetland for vegetation management/establishment and future maintenance as required. The stop logs will normally be installed to an elevation of 1108.0, 1.0 feet below the rim of the concrete box (1109.0). The outlet pipe is proposed as a 36” reinforced concrete pipe with an upstream invert of 1103.0 and a downstream invert of 1102.3.

The wetland is proposed to meet NRCS CPS 656, which references both CPS 373 and CPS 410.

These standards have the principal and auxiliary spillway design storm requirement summarized below:

NRCS CPS 656

Principal spillway design to comply with CPS 378 Auxiliary spillway to pass 25-year, 24 hour storm

NRCS CPS 378

Principal spillway to pass 10-year, 24 hour storm Auxiliary spillway to pass 25-year, 24 hour storm

NRCS CPS 410

Principal spillway to pass 5-year, 24 hour storm Auxiliary spillway to pass 10-year, 24 hour storm

Since the structure is low hazard with a drainage area smaller than 250 acres (185 acres), the principal spillway must pass the 10-year, 24-hour storm according to NRCS 656 complying with NRCS 378. In lieu of the 10-year, 24-hour storm, the auxiliary spillway was sized to pass the 25-year, 24-hour storm to meet NRCS 656 requirements. NRCS 656 references both NRCS 378 and 410, the more conservative of the two standards were used for design. Therefore, the principal spillway was designed to pass the 10-year, 24-hour storm producing a rainfall depth of 4.46”. The principal spillway storm will produce a wetland discharge of 93 cfs through the principal spillway and a peak water surface elevation of 1109.61’. The auxiliary spillway elevation is proposed at 1111.00’. The auxiliary spillway was designed to pass the 25-year, 24-hour storm producing a rainfall depth of 5.44”. The auxiliary spillway storm will produce a wetland discharge of 144 cfs through the principal spillway and a peak water surface elevation of 1110.06’. The top of dam elevation is proposed at 1113.00’.

A cantilever outlet section was selected over a flared end section to extend the outlet beyond the embankment face and discharge above the normal water level of the downstream pond, allowing the pond to provide energy dissipation and reduce erosion potential. The cantilever outlet section outlets to a stabilized outlet location, providing adequate outlet protection while reducing construction complexity and long-term maintenance requirements.

FREEBOARD DESIGN

Per NRCS 378, the structure shall pass the 100-year, 24-hour storm without overtopping the dam. This equates to a storm producing a rainfall depth of 7.12”. The 100-year, 24-hour storm will produce a discharge of 270 cfs through the principal spillway and a peak water surface elevation of 1111.14. The top of dam elevation is set at 1113.00.

WATER QUALITY IMPROVEMENT

The wetland drawdown was designed to meet NRCS 656 requirements which states that the wetland will drawdown and return to design operating levels within 48 hours after a 10-year, 24-hour storm. The 10-year, 24-hour storm produced a 28-hour drawdown time.

NRCS 656 also states that to promote emergent vegetation, 50% or more of the pool area shall have depths from 0-24 inches. The wetland design has a depth distribution as follows which meets this requirement.

Depth Range Area (ac) Area (percentage) 0-24”

1.59 63.4%

24-36”

0.74 29.6%

Deeper than 36”

0.16 7.0%

SLOPE DESIGN

Side slopes were designed to meet NRCS 656 requirements which reference NRCS 378. Slopes designed with a ratio if three horizontal to one vertical (3:1) or flatter.

EMBANKMENT DESIGN

Per NRCS 378, top width required for dams with total heights less than 15 feet require a minimum of 10 feet top width. A 16-foot top width was requested by the landowner for this project and will also serve to help balance earthwork. Minimum settlement of 5% of the total height of the dam was accounted for on the final construction elevation of the dam. The construction plans show the 10’ high embankment being overbuilt by 5% to account for future settlement. (0.05 x 10’ = 0.5 Feet overbuild).

IMPOUNDMENT LIFE

The Impoundment life was calculated using estimated sediment delivery and NRCS standard sheet and rill erosion rate estimates. The erosion rates are based on the Average Annual Soil Erosion by Water on Cropland and CRP Land, 1982, published by USDA and revised in December 2000. This indicated that the erosion rates for the area ranged from 3 to 5 tons per acre per year. Furthermore, sediment delivery was based on NRCS FOTG “Erosion & Sediment Delivery”, (Chart I: Estimated sediment delivery for landform regions). The chart indicated a sediment delivery percentage of approximately 8% for a 185-acre drainage area located in the Des Moines Lobe. Finally, the estimated sediment storage is based on the normal pool storage volume of 3.47 ac-ft.

Based on the assumed soil erosion rate (5 T/Ac/yr), delivery ratio (8%), a sediment unit weight of 100 PCF, and sediment capture rate of 70% of delivered sediment, approximately 51.8 tons of sediment per year (1,036 CF) is anticipated to be retained in the wetland. With a total sediment capacity of 3.47 ac-ft, this equates to an expected impoundment life of 145 years.

GEOTECHNICAL INVESTIGATION AND EVALUATION

Excavation of two test pits in the proposed borrow area was completed by the landowner with the engineer present. Test pits showed 6-12 inches of topsoil underlain with suitable organic clay material for embankment construction. Deeper, beyond approximate 4 feet, yellow clay was encounters. The yellow clay material is proposed to be used for the embankment core and core trench.

DRAINAGE AREA MAP

SHOOFLY TRUST

(JENSEN, BILL)

SHOOFLY TRUST

JENSEN,

MARY & DAVID

JENSEN,

JOHN & SHANNON

JENSEN,

MARY & DAVID

KELSEY,

KURTIS & ARLISS

KELSEY,

KURTIS & ARLISS

KELSEY,

KURTIS & ARLISS

KELSEY,

KURTIS & ARLISS

SHOOFLY TRUST

(JENSEN, BILL)

SHOOFLY TRUST

(JENSEN, BILL)

SHOOFLY TRUST

(JENSEN, BILL)

DRAINAGE AREA

AREA = 185 ACRES

NORMAL POOL

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SOIL MAP/LAND

CHARACTERISTICS

Hydrologic Soil Group—Hardin County, Iowa (Jensen_HydrologicSoilGroup)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

9/28/2020

482800 483000 483200 483400 483600 483800 484000

482800 483000 483200 483400 483600 483800 484000

42° 30' 52'' N

2'

6' ' W

42° 30' 52'' N

1'

4' ' W

42° 29' 51'' N

2'

6' ' W

42° 29' 51'' N

1'

4' ' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 15N WGS84 0 400 800 1600 2400

Feet 0 100 200 400 600

Meters Map Scale: 1:9,120 if printed on A portrait (8.5" x 11") sheet.

MAP LEGEND MAP INFORMATION

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

Soils Soil Rating Polygons

A

A/D

B

B/D

C

C/D

D

Not rated or not available

Soil Rating Lines A

A/D

B

B/D

C

C/D

D

Not rated or not available

Soil Rating Points A

A/D

B

B/D

C

C/D

D

Not rated or not available

Water Features Streams and Canals

Transportation Rails

Interstate Highways

US Routes

Major Roads

Local Roads

Background Aerial Photography

The soil surveys that comprise your AOI were mapped at 1:15,800.

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

Source of Map: Natural Resources Conservation Service Web Soil Survey URL:

Coordinate System: Web Mercator (EPSG:3857)

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

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

Soil Survey Area: Hardin County, Iowa Survey Area Data: Version 27, Jun 10, 2020

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

Date(s) aerial images were photographed: Jul 12, 2014—Feb 21, 2017

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

Hydrologic Soil Group—Hardin County, Iowa (Jensen_HydrologicSoilGroup)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

9/28/2020

PRINCIPAL SPILLWAY

CALCULATIONS

Hydrologic Soil Group

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

27B Terril loam, 2 to 6 percent slopes

B 4.7 2.7%

201B Coland-Terril complex, 2 to 5 percent slopes

C/D 2.0 1.1%

L55 Nicollet loam, 1 to 3 percent slopes

B/D 19.5 11.3%

L95 Harps clay loam, Bemis moraine, 0 to 2 percent slopes

C/D 0.3 0.2%

L107 Webster clay loam, Bemis moraine, 0 to 2 percent slopes

C/D 1.7 1.0%

L138B Clarion loam, Bemis moraine, 2 to 6 percent slopes

B 37.0 21.6%

L138C2 Clarion loam, Bemis moraine, 6 to 10 percent slopes, moderately eroded

B 8.8 5.1%

L236B Lester loam, Bemis moraine, 2 to 6 percent slopes

C 9.3 5.4%

L236C2 Lester loam, Bemis moraine, 6 to 10 percent slopes, moderately eroded

C 2.6 1.5%

L329 Webster-Nicollet complex, Bemis moraine, 0 to 3 percent slopes

C/D 69.4 40.4%

L507 Canisteo clay loam, Bemis moraine, 0 to 2 percent slopes

C/D 1.8 1.1%

L638C2 Clarion-Storden complex, Bemis moraine, 6 to 10 percent slopes, moderately eroded

B 14.4 8.4%

L638D2 Omsrud-Storden complex, Bemis moraine, 10 to 16 percent slopes, moderately eroded

B 0.1 0.1%

Totals for Area of Interest 171.7 100.0%

Hydrologic Soil Group—Hardin County, Iowa Jensen_HydrologicSoilGroup

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Description

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

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

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

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

These soils have a moderate rate of water transmission.

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

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

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

Rating Options

Aggregation Method: Dominant Condition

Component Percent Cutoff: None Specified

Tie-break Rule: Higher

Hydrologic Soil Group—Hardin County, Iowa Jensen_HydrologicSoilGroup

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Unit Hydrograph Summary, 10 years (Post-Development 10 year)

135th DA - West

Unit Hydrograph Summary, 100 years (Post-Development 100 year)

Unit Hydrograph Summary, 25 years (Post-Development 25 year)

Unit Hydrograph Summary, 10 years (Post-Development 10 year)

135th DA - East

Time of Concentration Calculations, 100 years (Post- Development 100 year)

Time of Concentration Calculations, 25 years (Post- Development 25 year)

Time of Concentration Calculations, 10 years (Post- Development 10 year)

West Tile DA

Time of Concentration Calculations, 100 years (Post- Development 100 year)

Time of Concentration Calculations, 25 years (Post- Development 25 year)

Time of Concentration Calculations, 10 years (Post- Development 10 year)

OO Ave DA

Time of Concentration Calculations, 100 years (Post- Development 100 year)

Time of Concentration Calculations, 25 years (Post- Development 25 year)

Time of Concentration Calculations, 10 years (Post- Development 10 year)

East Tile DA

Time of Concentration Calculations, 100 years (Post- Development 100 year)

Time of Concentration Calculations, 25 years (Post- Development 25 year)

Time of Concentration Calculations, 10 years (Post- Development 10 year)

135th DA - West

Time of Concentration Calculations, 100 years (Post- Development 100 year)

Time of Concentration Calculations, 25 years (Post- Development 25 year)

Time of Concentration Calculations, 10 years (Post- Development 10 year)

135th DA - East

9Time-Depth Curve, 25 years (Post-Development 25 year)

7Time-Depth Curve, 100 years (Post-Development 100 year)

5Time-Depth Curve, 10 years (Post-Development 10 year)

MSE3

Master Network Summary 2

Table of Contents

Table of Contents

Elevation-Area Volume Curve, 100 years (Post-Development 100 year)

Elevation-Area Volume Curve, 25 years (Post-Development 25 year)

Elevation-Area Volume Curve, 10 years (Post-Development 10 year)

Proposed Wetland

104Time vs. Volume, 100 years (Post-Development 100 year)

101Time vs. Volume, 25 years (Post-Development 25 year)

98Time vs. Volume, 10 years (Post-Development 10 year)

Proposed Wetland

95Time vs. Elevation, 100 years (Post-Development 100 year)

92Time vs. Elevation, 25 years (Post-Development 25 year)

89Time vs. Elevation, 10 years (Post-Development 10 year)

Proposed Wetland (OUT)

Addition Summary, 100 years (Post-Development 100 yea 88r)

Addition Summary, 25 years (Post-Development 25 year) 87

Addition Summary, 10 years (Post-Development 10 year) 86

Wetland Outfall

Unit Hydrograph Summary, 100 years (Post-Development 100 year)

Unit Hydrograph Summary, 25 years (Post-Development 25 year)

Unit Hydrograph Summary, 10 years (Post-Development 10 year)

West Tile DA

Unit Hydrograph Summary, 100 years (Post-Development 100 year)

Unit Hydrograph Summary, 25 years (Post-Development 25 year)

Unit Hydrograph Summary, 10 years (Post-Development 10 year)

OO Ave DA

Unit Hydrograph Summary, 100 years (Post-Development 100 year)

Unit Hydrograph Summary, 25 years (Post-Development 25 year)

Unit Hydrograph Summary, 10 years (Post-Development 10 year)

East Tile DA

Unit Hydrograph Summary, 100 years (Post-Development 100 year)

Unit Hydrograph Summary, 25 years (Post-Development 25 year)

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Jensen_Wetland - Section 5 - MSE3_AdjustedCN.ppc

IDALS - HAR892022C

Subsection: Master Network Summary

Catchments Summary

Peak Flow (ft³/s)

Time to Peak (min)

Hydrograph Volume (ac-ft)

Return Event

(years)

ScenarioLabel

46.09762.0007.22910Post-Development 10 year

East Tile DA

76.20762.00011.22725Post-Development 25 year

East Tile DA

135.43762.00019.096100Post-Development 100 year

East Tile DA

28.34762.0004.27410Post-Development 10 year

135th DA - East

46.60762.0006.63825Post-Development 25 year

135th DA - East

82.46756.00011.290100Post-Development 100 year

135th DA - East

12.91759.0001.76310Post-Development 10 year

135th DA - West

20.68756.0002.68625Post-Development 25 year

135th DA - West

35.88753.0004.478100Post-Development 100 year

135th DA - West

19.22750.0002.25310Post-Development 10 year

OO Ave DA

30.88747.0003.43125Post-Development 25 year

OO Ave DA

53.48747.0005.721100Post-Development 100 year

OO Ave DA

11.75744.0001.20710Post-Development 10 year

West Tile DA

18.76744.0001.83825Post-Development 25 year

West Tile DA

32.45741.0003.064100Post-Development 100 year

West Tile DA

Node Summary

Peak Flow (ft³/s)

Time to Peak (min)

Hydrograph Volume (ac-ft)

Return Event

(years)

ScenarioLabel

47.51816.00015.17310Post-Development 10 year

Wetland Outfall

79.48816.00023.53325Post-Development 25 year

Wetland Outfall

143.83804.00040.546100Post-Development 100 year

Wetland Outfall

Pond Summary

IDALS - HAR892022C

Subsection: Master Network Summary

Pond Summary

Maximum Pond Storage

(ac-ft)

Maximum Water

Surface Elevation

(ft)

Peak Flow (ft³/s)

Time to Peak (min)

Hydrograph Volume (ac-ft)

Return Event

(years)

ScenarioLabel

(N/A)(N/A)93.21768.00016.67110Post- Development 10 year

Proposed Wetland (IN)

9.0571,109.6147.51816.00015.17310Post- Development 10 year

Proposed Wetland

(OUT)

(N/A)(N/A)143.68762.00025.54825Post- Development 25 year

Proposed Wetland (IN)

11.1741,110.0679.48816.00023.53325Post- Development 25 year

Proposed Wetland

(OUT)

(N/A)(N/A)269.77765.00043.003100Post- Development 100 year

Proposed Wetland (IN)

17.4911,111.14143.83804.00040.546100Post- Development 100 year

Proposed Wetland

(OUT)

(N/A)(N/A)30.03762.0004.31910Post- Development 10 year

135th Basin

- East (IN)

0.6851,121.2622.45780.0004.27810Post- Development 10 year

135th Basin

- East (OUT)

(N/A)(N/A)53.32762.0006.94125Post- Development 25 year

135th Basin

- East (IN)

1.4861,122.6830.73789.0006.88625Post- Development 25 year

135th Basin

- East (OUT)

(N/A)(N/A)102.18756.00012.394100Post- Development 100 year

135th Basin

- East (IN)

2.5761,123.2885.98771.00012.322100Post- Development 100 year

135th Basin

- East (OUT)

(N/A)(N/A)12.91759.0001.76310Post- Development 10 year

135th Basin

- West (IN)

0.1221,120.7912.61762.0001.75810Post- Development 10 year

135th Basin

- West

(OUT)

(N/A)(N/A)20.68756.0002.68625Post- Development 25 year

135th Basin

- West (IN)

27 Siemon Company Drive Suite 200 W Page 3 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Jensen_Wetland - Section 5 - MSE3_AdjustedCN.ppc

Subsection: Master Network Summary

Pond Summary

Maximum Pond Storage

(ac-ft)

Maximum Water

Surface Elevation

(ft)

Peak Flow (ft³/s)

Time to Peak (min)

Hydrograph Volume (ac-ft)

Return Event

(years)

ScenarioLabel

0.1641,121.1720.35759.0002.67925Post- Development 25 year

135th Basin

- West

(OUT)

(N/A)(N/A)35.88753.0004.478100Post- Development 100 year

135th Basin

- West (IN)

0.2251,121.6435.46756.0004.468100Post- Development 100 year

135th Basin

- West

(OUT)

(N/A)(N/A)19.22750.0002.25310Post- Development 10 year

OO Ave Basin (IN)

0.2031,119.0014.45765.0002.25210Post- Development 10 year

OO Ave Basin (OUT)

(N/A)(N/A)30.88747.0003.43125Post- Development 25 year

OO Ave Basin (IN)

0.4441,119.4824.25762.0003.43125Post- Development 25 year

OO Ave Basin (OUT)

(N/A)(N/A)53.48747.0005.721100Post- Development 100 year

OO Ave Basin (IN)

0.5591,119.6352.22750.0005.720100Post- Development 100 year

OO Ave Basin (OUT)

(N/A)(N/A)11.75744.0001.20710Post- Development 10 year

West Tile Basin (IN)

0.5181,119.001.62828.0001.19910Post- Development 10 year

West Tile Basin (OUT)

(N/A)(N/A)18.76744.0001.83825Post- Development 25 year

West Tile Basin (IN)

1.0081,119.361.65852.0001.62825Post- Development 25 year

West Tile Basin (OUT)

(N/A)(N/A)32.45741.0003.064100Post- Development 100 year

West Tile Basin (IN)

1.4941,119.647.40792.0002.499100Post- Development 100 year

West Tile Basin (OUT)

27 Siemon Company Drive Suite 200 W Page 4 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Scenario: Post-Development 10 year

Label: MSE3 Storm Event: 10 year

Subsection: Time-Depth Curve Return Event: 10 years

Time-Depth Curve: 10 year

10 year Label

Start Time 0.000 min

Increment 6.000 min

End Time 1,440.000 min

Return Event 10 years

CUMULATIVE RAINFALL (in)

Output Time Increment = 6.000 min

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (min)

0.0053070.0038400.0024750.0011910.0000000.000

0.0139150.0119970.0102130.0084740.00682430.000

0.0247080.0223450.0201150.0179740.01587860.000

0.0376870.0349220.0322460.0296590.02711790.000

0.0528960.0496840.0465620.0435300.040586120.000

0.0702900.0666320.0630640.0595860.056196150.000

0.0899140.0858100.0817960.0778720.074036180.000

0.1116780.1071740.1027140.0983430.094061210.000

0.1356730.1307230.1258170.1210440.116317240.000

0.1618980.1564570.1511490.1458870.140758270.000

0.1902640.1844210.1786680.1729590.167384300.000

0.2208590.2145710.2083710.2022610.196195330.000

0.2536400.2469060.2402600.2337040.227237360.000

0.2886510.2814710.2743790.2673770.260464390.000

0.3258480.3182210.3106840.3032350.295921420.000

0.3652290.3571570.3492180.3413240.333519450.000

0.4067970.3983230.3898930.3815980.373347480.000

0.4505940.4416740.4327980.4240570.415404510.000

0.5185200.5034890.4886380.4740090.459603540.000

0.5967480.5806920.5648140.5492040.533728570.000

0.6800610.6630240.6461200.6294400.612982600.000

0.8203720.7845590.7520900.7230550.697366630.000

1.0500180.9973450.9480180.9020800.859531660.000

1.6611271.4470471.2961651.1876981.106080690.000

3.2723023.1638353.0129532.7988732.064489720.000

3.5579203.5119823.4626553.4099823.353920750.000

3.7369453.7079103.6754413.6396283.600469780.000

3.8305603.8138803.7969763.7799393.762634810.000

3.9107963.8951863.8793083.8632523.847018840.000

3.9859913.9713623.9565113.9414803.926272870.000

4.0359434.0272024.0183264.0094064.000397900.000

4.0784024.0701074.0616774.0532034.044596930.000

4.1186764.1107824.1028434.0947714.086653960.000

4.1567654.1493164.1417794.1341524.126481990.000

27 Siemon Company Drive Suite 200 W Page 5 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: MSE3 Storm Event: 10 year

Subsection: Time-Depth Curve Return Event: 10 years

CUMULATIVE RAINFALL (in)

Output Time Increment = 6.000 min

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (min)

4.1926234.1856214.1785294.1713494.1640791,020.000

4.2262964.2197404.2130944.2063604.1995361,050.000

4.2577394.2516294.2454294.2391414.2327631,080.000

4.2870414.2813324.2755794.2697364.2638051,110.000

4.3141134.3088514.3035434.2981024.2926161,140.000

4.3389564.3341834.3292774.3243274.3192421,170.000

4.3616574.3572864.3528264.3483224.3436831,200.000

4.3821284.3782044.3741904.3700864.3659391,230.000

4.4004144.3969364.3933684.3897104.3859641,260.000

4.4164704.4134384.4103164.4071044.4038041,290.000

4.4303414.4277544.4250784.4223134.4194141,320.000

4.4420264.4398854.4376554.4352924.4328831,350.000

4.4515264.4497874.4480034.4460854.4441221,380.000

4.4588094.4575254.4561604.4546934.4531761,410.000

(N/A)(N/A)(N/A)(N/A)4.4600001,440.000

27 Siemon Company Drive Suite 200 W Page 6 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Scenario: Post-Development 100 year

Label: MSE3 Storm Event: 100 year

Subsection: Time-Depth Curve Return Event: 100 years

Time-Depth Curve: 100 year

100 year Label

Start Time 0.000 min

Increment 6.000 min

End Time 1,440.000 min

Return Event 100 years

CUMULATIVE RAINFALL (in)

Output Time Increment = 6.000 min

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (min)

0.0084730.0061300.0039520.0019010.0000000.000

0.0222140.0191530.0163050.0135280.01089430.000

0.0394450.0356710.0321110.0286940.02534760.000

0.0601640.0557500.0514780.0473480.04329090.000

0.0844430.0793170.0743330.0694910.064792120.000

0.1122110.1063730.1006770.0951230.089712150.000

0.1435390.1369890.1305810.1243150.118192180.000

0.1782850.1710940.1639740.1569960.150161210.000

0.2165900.2086870.2008550.1932370.185690240.000

0.2584560.2497700.2412970.2328950.224707270.000

0.3037390.2944120.2852270.2761140.267214300.000

0.3525820.3425430.3326460.3228920.313209330.000

0.4049140.3941630.3835540.3730880.362764360.000

0.4608060.4493430.4380220.4268440.415808390.000

0.5201870.5080120.4959790.4840890.472412420.000

0.5830570.5701700.5574960.5448940.532434450.000

0.6494150.6358870.6224300.6091870.596015480.000

0.7193340.7050940.6909250.6769700.663157510.000

0.8277710.8037770.7800670.7567140.733716540.000

0.9526560.9270240.9016770.8767570.852050570.000

1.0856581.0584591.0314741.0048460.978573600.000

1.3096531.2524791.2006461.1542941.113283630.000

1.6762621.5921741.5134271.4400911.372166660.000

2.6518442.3100842.0692141.8960561.765760690.000

5.2239445.0507864.8099164.4681563.295777720.000

5.6799095.6065735.5278265.4437385.354240750.000

5.9657065.9193545.8675215.8103475.747834780.000

6.1151546.0885266.0615416.0343426.006717810.000

6.2432436.2183236.1929766.1673446.141427840.000

6.3632866.3399336.3162236.2922296.267950870.000

6.4430306.4290756.4149066.4006666.386284900.000

6.5108136.4975706.4841136.4705856.456843930.000

6.5751066.5625046.5498306.5369436.523985960.000

6.6359116.6240216.6119886.5998136.587566990.000

27 Siemon Company Drive Suite 200 W Page 7 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: MSE3 Storm Event: 100 year

Subsection: Time-Depth Curve Return Event: 100 years

CUMULATIVE RAINFALL (in)

Output Time Increment = 6.000 min

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (min)

6.6931566.6819786.6706576.6591946.6475881,020.000

6.7469126.7364466.7258376.7150866.7041921,050.000

6.7971086.7873546.7774576.7674186.7572361,080.000

6.8438866.8347736.8255886.8162616.8067911,110.000

6.8871056.8787036.8702306.8615446.8527861,140.000

6.9267636.9191456.9113136.9034106.8952931,170.000

6.9630046.9560266.9489066.9417156.9343101,200.000

6.9956856.9894196.9830116.9764616.9698391,230.000

7.0248777.0193237.0136277.0077897.0018081,260.000

7.0505097.0456677.0406837.0355577.0302881,290.000

7.0726527.0685227.0642507.0598367.0552081,320.000

7.0913067.0878897.0843297.0805557.0767101,350.000

7.1064727.1036957.1008477.0977867.0946531,380.000

7.1180997.1160487.1138707.1115277.1091061,410.000

(N/A)(N/A)(N/A)(N/A)7.1200001,440.000

27 Siemon Company Drive Suite 200 W Page 8 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Scenario: Post-Development 25 year

Label: MSE3 Storm Event: 25 year

Subsection: Time-Depth Curve Return Event: 25 years

Time-Depth Curve: 25 year

25 year Label

Start Time 0.000 min

Increment 6.000 min

End Time 1,440.000 min

Return Event 25 years

CUMULATIVE RAINFALL (in)

Output Time Increment = 6.000 min

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (min)

0.0064740.0046840.0030190.0014520.0000000.000

0.0169730.0146340.0124580.0103360.00832330.000

0.0301380.0272540.0245340.0219230.01936660.000

0.0459680.0425950.0393310.0361760.03307590.000

0.0645180.0606020.0567940.0530940.049504120.000

0.0857340.0812740.0769220.0726780.068544150.000

0.1096700.1046660.0997700.0949820.090304180.000

0.1362180.1307230.1252830.1199520.114730210.000

0.1654850.1594460.1534620.1476420.141875240.000

0.1974720.1908350.1843620.1779420.171686270.000

0.2320700.2249440.2179260.2109630.204163300.000

0.2693890.2617180.2541570.2467040.239306330.000

0.3093730.3011580.2930530.2850560.277168360.000

0.3520770.3433180.3346690.3261280.317696390.000

0.3974460.3881440.3789500.3698660.360944420.000

0.4454820.4356350.4259520.4163230.406803450.000

0.4961820.4858460.4755650.4654460.455382480.000

0.5496030.5387230.5278980.5172350.506682510.000

0.6324540.6141220.5960060.5781630.560592540.000

0.7278720.7082880.6889220.6698820.651005570.000

0.8294910.8087100.7880930.7677470.747674600.000

1.0006340.9569500.9173470.8819330.850598630.000

1.2807391.2164931.1563261.1002941.048397660.000

2.0261281.7650081.5809731.4486721.349120690.000

3.9913283.8590273.6749923.4138722.518122720.000

4.3397064.2836744.2235074.1592614.090880750.000

4.5580674.5226534.4830504.4393664.391603780.000

4.6722534.6519074.6312904.6105094.589402810.000

4.7701184.7510784.7317124.7121284.692326840.000

4.8618374.8439944.8258784.8075464.788995870.000

4.9227654.9121024.9012774.8903974.879408900.000

4.9745544.9644354.9541544.9438184.933318930.000

5.0236775.0140485.0043654.9945184.984618960.000

5.0701345.0610505.0518565.0425545.033197990.000

27 Siemon Company Drive Suite 200 W Page 9 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: MSE3 Storm Event: 25 year

Subsection: Time-Depth Curve Return Event: 25 years

CUMULATIVE RAINFALL (in)

Output Time Increment = 6.000 min

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (min)

5.1138725.1053315.0966825.0879235.0790561,020.000

5.1549445.1469475.1388425.1306275.1223041,050.000

5.1932965.1858435.1782825.1706115.1628321,080.000

5.2290375.2220745.2150565.2079305.2006941,110.000

5.2620585.2556385.2491655.2425285.2358371,140.000

5.2923585.2865385.2805545.2745155.2683141,170.000

5.3200485.3147175.3092775.3037825.2981251,200.000

5.3450185.3402305.3353345.3303305.3252701,230.000

5.3673225.3630785.3587265.3542665.3496961,260.000

5.3869065.3832065.3793985.3754825.3714561,290.000

5.4038245.4006695.3974055.3940325.3904961,320.000

5.4180775.4154665.4127465.4098625.4069251,350.000

5.4296645.4275425.4253665.4230275.4206341,380.000

5.4385485.4369815.4353165.4335265.4316771,410.000

(N/A)(N/A)(N/A)(N/A)5.4400001,440.000

27 Siemon Company Drive Suite 200 W Page 10 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - East Storm Event: 10 year

Subsection: Time of Concentratio Return Event: 10 yearsn Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,995.00 ft

CN 61.000

Slope 0.031 ft/ft

Average Velocity 0.63 ft/s

52.920 min Segment Time of Concentration

Time of Concentration (Composite)

52.920 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 11 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - East Storm Event: 10 year

Subsection: Time of Concentratio Return Event: 10 yearsn Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 13 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - East Storm Event: 25 year

Subsection: Time of Concentratio Return Event: 25 yearsn Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,995.00 ft

CN 61.000

Slope 0.031 ft/ft

Average Velocity 0.63 ft/s

52.920 min Segment Time of Concentration

Time of Concentration (Composite)

52.920 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 14 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - East Storm Event: 25 year

Subsection: Time of Concentratio Return Event: 25 yearsn Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 16 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - East Storm Event: 100 year

Subsection: Time of Concentrati Return Event: 100 yearson Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,995.00 ft

CN 61.000

Slope 0.031 ft/ft

Average Velocity 0.63 ft/s

52.920 min Segment Time of Concentration

Time of Concentration (Composite)

52.920 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 17 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - East Storm Event: 100 year

Subsection: Time of Concentrati Return Event: 100 yearson Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 19 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - West Storm Event: 10 year

Subsection: Time of Concentratio Return Event: 10 yearsn Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,940.00 ft

CN 61.000

Slope 0.038 ft/ft

Average Velocity 0.69 ft/s

46.988 min Segment Time of Concentration

Time of Concentration (Composite)

46.988 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 20 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - West Storm Event: 10 year

Subsection: Time of Concentratio Return Event: 10 yearsn Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 22 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - West Storm Event: 25 year

Subsection: Time of Concentratio Return Event: 25 yearsn Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,940.00 ft

CN 61.000

Slope 0.038 ft/ft

Average Velocity 0.69 ft/s

46.988 min Segment Time of Concentration

Time of Concentration (Composite)

46.988 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 23 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - West Storm Event: 25 year

Subsection: Time of Concentratio Return Event: 25 yearsn Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 25 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - West Storm Event: 100 year

Subsection: Time of Concentrati Return Event: 100 yearson Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,940.00 ft

CN 61.000

Slope 0.038 ft/ft

Average Velocity 0.69 ft/s

46.988 min Segment Time of Concentration

Time of Concentration (Composite)

46.988 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 26 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - West Storm Event: 100 year

Subsection: Time of Concentrati Return Event: 100 yearson Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 28 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: East Tile DA Storm Event: 10 year

Subsection: Time of Concentratio Return Event: 10 yearsn Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 2,165.00 ft

CN 61.000

Slope 0.032 ft/ft

Average Velocity 0.65 ft/s

55.435 min Segment Time of Concentration

Time of Concentration (Composite)

55.435 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 29 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: East Tile DA Storm Event: 10 year

Subsection: Time of Concentratio Return Event: 10 yearsn Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 31 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: East Tile DA Storm Event: 25 year

Subsection: Time of Concentratio Return Event: 25 yearsn Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 2,165.00 ft

CN 61.000

Slope 0.032 ft/ft

Average Velocity 0.65 ft/s

55.435 min Segment Time of Concentration

Time of Concentration (Composite)

55.435 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 32 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: East Tile DA Storm Event: 25 year

Subsection: Time of Concentratio Return Event: 25 yearsn Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 34 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: East Tile DA Storm Event: 100 year

Subsection: Time of Concentrati Return Event: 100 yearson Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 2,165.00 ft

CN 61.000

Slope 0.032 ft/ft

Average Velocity 0.65 ft/s

55.435 min Segment Time of Concentration

Time of Concentration (Composite)

55.435 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 35 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: East Tile DA Storm Event: 100 year

Subsection: Time of Concentrati Return Event: 100 yearson Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 37 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: OO Ave DA Storm Event: 10 year

Subsection: Time of Concentratio Return Event: 10 yearsn Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,402.00 ft

CN 61.000

Slope 0.036 ft/ft

Average Velocity 0.63 ft/s

36.880 min Segment Time of Concentration

Time of Concentration (Composite)

36.880 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 38 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: OO Ave DA Storm Event: 10 year

Subsection: Time of Concentratio Return Event: 10 yearsn Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 40 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: OO Ave DA Storm Event: 25 year

Subsection: Time of Concentratio Return Event: 25 yearsn Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,402.00 ft

CN 61.000

Slope 0.036 ft/ft

Average Velocity 0.63 ft/s

36.880 min Segment Time of Concentration

Time of Concentration (Composite)

36.880 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 41 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: OO Ave DA Storm Event: 25 year

Subsection: Time of Concentratio Return Event: 25 yearsn Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 43 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: OO Ave DA Storm Event: 100 year

Subsection: Time of Concentrati Return Event: 100 yearson Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,402.00 ft

CN 61.000

Slope 0.036 ft/ft

Average Velocity 0.63 ft/s

36.880 min Segment Time of Concentration

Time of Concentration (Composite)

36.880 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 44 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: OO Ave DA Storm Event: 100 year

Subsection: Time of Concentrati Return Event: 100 yearson Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 46 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: West Tile DA Storm Event: 10 year

Subsection: Time of Concentratio Return Event: 10 yearsn Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,103.00 ft

CN 61.000

Slope 0.038 ft/ft

Average Velocity 0.62 ft/s

29.713 min Segment Time of Concentration

Time of Concentration (Composite)

29.713 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 47 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: West Tile DA Storm Event: 10 year

Subsection: Time of Concentratio Return Event: 10 yearsn Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 49 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: West Tile DA Storm Event: 25 year

Subsection: Time of Concentratio Return Event: 25 yearsn Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,103.00 ft

CN 61.000

Slope 0.038 ft/ft

Average Velocity 0.62 ft/s

29.713 min Segment Time of Concentration

Time of Concentration (Composite)

29.713 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 50 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: West Tile DA Storm Event: 25 year

Subsection: Time of Concentratio Return Event: 25 yearsn Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 52 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: West Tile DA Storm Event: 100 year

Subsection: Time of Concentrati Return Event: 100 yearson Calculations

Time of Concentration Results

Segment #1: SCS Lag

Hydraulic Length 1,103.00 ft

CN 61.000

Slope 0.038 ft/ft

Average Velocity 0.62 ft/s

29.713 min Segment Time of Concentration

Time of Concentration (Composite)

29.713 min Time of Concentration (Composite)

27 Siemon Company Drive Suite 200 W Page 53 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: West Tile DA Storm Event: 100 year

Subsection: Time of Concentrati Return Event: 100 yearson Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.Tc = 5)

Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

27 Siemon Company Drive Suite 200 W Page 55 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - East Storm Event: 10 year

Subsection: Unit Hydrograph Sum Return Event: 10 yearsmary

Storm Event 10 year

Return Event 10 years

Duration 1,440.000 min

Depth 4.460000 in

52.920 min Time of Concentration (Composite)

Area (User Defined) 48.800 acres

7.056 min Computational Time Increment

Time to Peak (Computed) 762.043 min

Flow (Peak, Computed) 28.35 ft³/s

Output Increment 3.000 min

762.000 min Time to Flow (Peak Interpolated Output)

28.34 ft³/s Flow (Peak Interpolated Output)

Drainage Area

SCS CN (Composite) 61.000

Area (User Defined) 48.800 acres

6.393443 in Maximum Retention (Pervious)

1.278689 in Maximum Retention (Pervious, 20 percent)

Cumulative Runoff

1.057024 in Cumulative Runoff Depth (Pervious)

Runoff Volume (Pervious) 4.299 ac-ft

Hydrograph Volume (Area under Hydrograph curve)

Volume 4.274 ac-ft

SCS Unit Hydrograph Parameters

52.920 min Time of Concentration (Composite)

7.056 min Computational Time Increment

483.432 Unit Hydrograph Shape Factor

K Factor 0.749

Receding/Rising, Tr/Tp 1.670

27 Siemon Company Drive Suite 200 W Page 56 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Label: 135th DA - East Storm Event: 10 year

Subsection: Unit Hydrograph Sum Return Event: 10 yearsmary

SCS Unit Hydrograph Parameters

Unit peak, qp 62.69 ft³/s

Unit peak time, Tp 35.280 min

Unit receding limb, Tr 141.119 min

Total unit time, Tb 176.399 min

27 Siemon Company Drive Suite 200 W Page 57 of 111 Watertown, CT 06795 USA +1-203-755-1666

10/12/2023

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc.