5-25-20_WINN970905C_H&H_Report.pdf

STORM WATER CALCULATIONS

For:

BOUSKA WETLAND

WINN970905C

Iowa Department of Agriculture and Land Stewardship

Ridgeway, Iowa

S-H PROJECT # 2240006350

September 22nd, 2025

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: Anthony J Harbaugh, P.E.____ Date: _________________________

My license renewal date is December 31, 2025.

Pages, sheets, or divisions covered by this certification: ________ _Stormwater Report and Attachments __________________

Prepared by:

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

(515) 223-8104

TABLE OF CONTENTS

1. Project Summary

2. Drainage Area Map

3. Soil Map/Land Characteristics

4. Hydrology & Hydraulic Model Output

PROJECT SUMMARY

GENERAL

The proposed work includes construction of a wetland to the north of Spillville, IA. The location can be more specifically described as the SW ¼ of Section 5, Township 97 North, Range 9 West of the Fifth Principal meridian, Winneshiek County, Iowa. A dam and sheet pile weir 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

WATER CONTROL STRUCTURE – LOW FLOW SPILLWAY

The water control structure is a 48” circular CMP riser equipped with stop logs for water elevation control. The stop logs will be maintained approximately 1 inch below the crest of the sheet pile to provide passage of low flow. An 18’’ CMP will enter the structure from the pool area. An 18” CMP discharge pipe will run south and daylight into the proposed plunge pool then into the existing 4’ X 5’ RCP box culvert running under Conover Road.

PRINCIPAL SPILLWAY AND FREEBOARD DESIGN

The principal spillway consists of a 40’ wide steel sheet pile structure in the embankment at an elevation of 1154.10’. No auxiliary spillway will be provided. The top of dam is set to an elevation of 1159.00. The following standards were used to design the principal spillway: NRCS 378, NRCS 410, and NRCS 656.

A summary of the design criteria is listed below:

NRCS 378:

Freeboard Capacity - 50-year, 24-hour storm. No auxiliary spillway will be provided, two feet of freeboard from top of dam is required.

NRCS 410:

Freeboard Capacity - 10-year, 24-hour storm

NRCS 656:

Freeboard Capacity - 25-year, 24-hour storm without overtopping embankment, refers to NRCS 378 -for all other spillway requirements.

Using the more conservative of these standards, the wetland was designed to pass the 50-year, 24-hour storm, according to NRCS 378. Based on NRCS 378, the design storm shall be the 50-year, 24-hour storm and the design shall be passed through the principal spillway while providing at least two feet of freeboard to the top of dam. This equates to a storm producing a rainfall depth of 6.50”. The 50-year, 24-hour storm will produce a discharge of 466.76 cfs through the principal spillway and a peak water surface elevation of 1156.21’. The top of dam elevation is set at 1159.00’, providing 2.79’ of freeboard.

WATER QUALITY IMPROVEMENT

The wetland drawdown was designed to meet NRCS 656 requirements. 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 18-hour drawdown frequency. To promote emergent vegetation, 50% or more of the pool area (80% for this design) shall have depths from 0-24 inches.

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 10-foot top width was chosen for this design. Minimum settlement of 5% of the total height of the dam was accounted for on the final construction elevation of the dam. This equates to a final construction elevation of 1159.50’ (10.3 feet x 0.05] + 1159.00). Per NRSC 656, an additional 1 foot of overfill was added to the embankment design 50 feet on each side of the principal spillway (elevation of 1160.00’).

IMPOUNDMENT LIFE

The Impoundment life was calculated using estimated sediment delivery and NRCS standard total 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 5 to 8 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 20% for a 280.5-acre drainage area located in the Iowan Surface Landform. Finally, the estimated sediment storage is based on normal pool storage volume which equates to 2.80 ac-ft.

Based on the assumed soil erosion rate (5 T/Ac/yr), delivery ratio (20%), a sediment unit weight of 100 PCF, and sediment capture rate of 70% of delivered sediment, approximately 196.4 tons of sediment per year (3,927 CF) is anticipated to be retained in the wetland. With a total sediment capacity of 2.80 ac-ft, this equates to an expected impoundment life of 31 years.

GEOTECHNICAL INVESTIGATION AND EVALUATION

A geotechnical investigation has been completed by Terracon for the proposed wetland. A report compiling the findings and associated recommendations is included in the submittal package.

PONDPACK OUTPUT DESCRIPTIONS

Three different PondPack output reports have been included in the appendix. The first output report includes inputs and results from the existing conditions model. The purpose of the output is to document the performance of the existing culvert, prior to the proposed wetland being implemented.

The second output report includes results from a proposed model that does not consider tailwater effects from the existing culvert and roadway embankment. This model only allows water to move forward through the proposed wetland spillway and is included to verify that the principal spillway is appropriately sized to pass the anticipated peak flows while maintaining adequate freeboard.

The third and final output report includes results from a proposed model that allows tailwater effects between the roadway and the wetland to be considered. This model most accurately represents the combined performance of the wetland and roadway in the future condition, once the wetland is constructed. Since the roadway embankment is above the crest of the sheet pile weir, this model allows for the roadway embankment to back water up through sheet pile, resulting in a level pool from the road embankment through the wetland, more or less. This model indicates that the frequency at which Conover Road overtops will not be significantly impacted by the construction of the wetland.

DRAINAGE

AREA MAP

DRAINAGE AREA

AREA = 280.5 ACRES

WETLAND NORMAL POOL

AREA = 2.4 ACRES

FOREBAY NORMAL POOL

AREA = 0.2 ACRES

CONOVER RD

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SOIL MAP/LAND

CHARACTERISTICS

Hydrologic Soil Group—Winneshiek County, Iowa (globalwatershed)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

4/12/2024

585400 585600 585800 586000 586200 586400 586600 586800

585600 585800 586000 586200 586400 586600 586800

43° 15' 24'' N

6'

2' ' W

43° 15' 24'' N

5'

8' ' W

43° 14' 21'' N

6'

2' ' W

43° 14' 21'' N

5'

8' ' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 15N WGS84 0 450 900 1800 2700

Feet 0 100 200 400 600

Meters Map Scale: 1:9,390 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 1:12,000.

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: Winneshiek County, Iowa Survey Area Data: Version 32, Sep 12, 2023

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

Date(s) aerial images were photographed: Jul 31, 2020—Sep 2, 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—Winneshiek County, Iowa (globalwatershed)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

4/12/2024

Hydrologic Soil Group

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

198B Floyd loam, 1 to 4 percent slopes

B/D 3.1 1.1%

444B Jacwin loam, 2 to 5 percent slopes

C/D 2.7 1.0%

512B Marlean loam, 2 to 5 percent slopes

B 4.0 1.5%

512C Marlean loam, 5 to 9 percent slopes

B 17.9 6.5%

512C2 Marlean loam, 5 to 9 percent slopes, moderately eroded

B 30.8 11.2%

512D2 Marlean loam, 9 to 14 percent slopes, moderately eroded

B 33.0 12.0%

512E2 Marlean loam, 14 to 18 percent slopes, moderately eroded

B 3.0 1.1%

582B Kasson loam, 2 to 5 percent slopes

C 36.9 13.4%

814B Rockton loam, 2 to 5 percent slopes

C 91.8 33.3%

814C Rockton loam, 5 to 9 percent slopes

C 38.3 13.9%

914B Winneshiek loam, 2 to 5 percent slopes

C 5.0 1.8%

1489B Lawson-Ossian complex, 0 to 4 percent slopes

B/D 9.5 3.4%

Totals for Area of Interest 275.9 100.0%

Hydrologic Soil Group—Winneshiek County, Iowa globalwatershed

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—Winneshiek County, Iowa globalwatershed

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

PONDPACK

DIAGRAM

Scenario: Post-Development 10 year

Northern Drainage Area

Western Drainage Area

Buchanan Wetland

Wetland Outlet

Wetland Outfall

Wetland Outlet Structure

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PondPack CONNECT Edition [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBuchananCo_SloanWetland_Section 3_MSE4.ppc

Wetland DA

WINN C

Wetland

Culvert Pond

East Ditch Pond

East Ditch DA

HYDROLOGY &

HYDRAULIC OUTPUT

EXISTING CONDITIONS

43Time vs. Volume, 25 years (Post-Development 25 year)

41Time vs. Volume, 10 years (Post-Development 10 year)

Existing Basin

39Time vs. Elevation, 100 years (Post-Development 100 year)

37Time vs. Elevation, 50 years (Post-Development 50 year)

35Time vs. Elevation, 25 years (Post-Development 25 year)

33Time vs. Elevation, 10 years (Post-Development 10 year)

Existing Basin (OUT)

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

Unit Hydrograph Summary, 50 years (Post-Development 50 year)

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

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

Existing Basin DA

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

Unit Hydrograph Summary, 50 years (Post-Development 50 year)

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

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

East Ditch DA

16Runoff CN-Area, 100 years (Post-Development 100 year)

Existing Basin DA

15Runoff CN-Area, 100 years (Post-Development 100 year)

East Ditch DA

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

Existing Basin DA

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

East Ditch DA

9Time-Depth Curve, 50 years (Post-Development 50 year)

7Time-Depth Curve, 25 years (Post-Development 25 year)

5Time-Depth Curve, 100 years (Post-Development 100 year)

3Time-Depth Curve, 10 years (Post-Development 10 year)

MSE4

1Master Network Summary

Table of Contents

Table of Contents

71Outlet Input Data, 100 years (Post-Development 100 year)

69Outlet Input Data, 50 years (Post-Development 50 year)

67Outlet Input Data, 25 years (Post-Development 25 year)

65Outlet Input Data, 10 years (Post-Development 10 year)

Road Overtop

62Outlet Input Data, 100 years (Post-Development 100 year)

59Outlet Input Data, 50 years (Post-Development 50 year)

56Outlet Input Data, 25 years (Post-Development 25 year)

53Outlet Input Data, 10 years (Post-Development 10 year)

Culvert

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

Elevation-Area Volume Curve, 50 years (Post-Development 50 year)

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

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

Existing Basin

47Time vs. Volume, 100 years (Post-Development 100 year)

45Time vs. Volume, 50 years (Post-Development 50 year)

WINN970905C Stormwater Report - Existing Conditions Subsection: Master Network Summary

Catchments Summary

Peak Flow (ft³/s)

Time to Peak (hours)

Hydrograph Volume (ac-ft)

Return Event

(years)

ScenarioLabel

265.7113.00054.59710Post-Development 10 year

Existing Basin DA

372.2913.00076.15925Post-Development 25 year

Existing Basin DA

465.3313.00095.22250Post-Development 50 year

Existing Basin DA

567.7513.000116.443100Post-Development 100 year

Existing Basin DA

10.7912.3000.95410Post-Development 10 year

East Ditch DA

14.7612.3001.31425Post-Development 25 year

East Ditch DA

18.1812.3001.63150Post-Development 50 year

East Ditch DA

21.9212.3001.981100Post-Development 100 year

East Ditch DA

Node Summary

Peak Flow (ft³/s)

Time to Peak (hours)

Hydrograph Volume (ac-ft)

Return Event

(years)

ScenarioLabel

201.8313.60055.52310Post-Development 10 year

Culvert Outfall

228.9513.40072.53425Post-Development 25 year

Culvert Outfall

235.9913.20083.10850Post-Development 50 year

Culvert Outfall

240.1913.10093.450100Post-Development 100 year

Culvert Outfall

0.000.0000.00010Post-Development 10 year

Road Overflow Outfall

99.1313.4004.90125Post-Development 25 year

Road Overflow Outfall

209.9313.20013.70050Post-Development 50 year

Road Overflow Outfall

321.3513.10024.922100Post-Development 100 year

Road Overflow Outfall

Pond Summary

Maximum Pond Storage

(ac-ft)

Maximum Water

Surface Elevation

(ft)

Peak Flow (ft³/s)

Time to Peak (hours)

Hydrograph Volume (ac-ft)

Return Event

(years)

ScenarioLabel

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PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution CenterEXISTING_WINN C_Section 3 - MSE4.ppc

Subsection: Master Network Summary

Pond Summary

Maximum Pond Storage

(ac-ft)

Maximum Water

Surface Elevation

(ft)

Peak Flow (ft³/s)

Time to Peak (hours)

Hydrograph Volume (ac-ft)

Return Event

(years)

ScenarioLabel

(N/A)(N/A)267.7813.00055.55110Post- Development 10 year

Existing Basin (IN)

6.9351,155.53201.8313.60055.55110Post- Development 10 year

Existing Basin (OUT)

(N/A)(N/A)375.0213.00077.47325Post- Development 25 year

Existing Basin (IN)

10.7221,156.77328.0813.40077.47325Post- Development 25 year

Existing Basin (OUT)

(N/A)(N/A)468.6313.00096.85350Post- Development 50 year

Existing Basin (IN)

11.9371,157.11445.9313.20096.85350Post- Development 50 year

Existing Basin (OUT)

(N/A)(N/A)571.6613.000118.424100Post- Development 100 year

Existing Basin (IN)

12.7251,157.33561.5413.100118.424100Post- Development 100 year

Existing Basin (OUT)

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PondPack CONNECT Edition [10.02.00.01]

Storm Event: 10 yearLabel: MSE4

Return Event: 10 yearsSubsection: Time-Depth Curve

Time-Depth Curve: 10 year

10 year Label hours0.000Start Time hours0.100Increment hours24.000End Time years10Return Event

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

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

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

0.00.00.00.00.00.000 0.00.00.00.00.00.500 0.00.00.00.00.01.000 0.00.00.00.00.01.500 0.10.10.10.10.12.000 0.10.10.10.10.12.500 0.10.10.10.10.13.000 0.10.10.10.10.13.500 0.20.20.20.20.14.000 0.20.20.20.20.24.500 0.20.20.20.20.25.000 0.30.30.30.20.25.500 0.30.30.30.30.36.000 0.30.30.30.30.36.500 0.40.40.40.40.47.000 0.40.40.40.40.47.500 0.50.50.50.50.48.000 0.50.50.50.50.58.500 0.60.60.60.60.59.000 0.70.70.70.60.69.500 0.80.80.70.70.710.000 0.90.90.90.80.810.500 1.21.11.11.01.011.000 1.71.51.41.31.211.500 3.23.12.92.72.112.000 3.53.43.43.33.312.500 3.73.63.63.63.513.000 3.83.73.73.73.713.500 3.83.83.83.83.814.000 3.93.93.93.93.914.500 4.04.04.03.93.915.000 4.04.04.04.04.015.500 4.14.14.14.04.016.000 4.14.14.14.14.116.500

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PondPack CONNECT Edition [10.02.00.01]

Storm Event: 10 yearLabel: MSE4

Return Event: 10 yearsSubsection: Time-Depth Curve

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

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

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

4.24.24.14.14.117.000 4.24.24.24.24.217.500 4.24.24.24.24.218.000 4.34.34.34.24.218.500 4.34.34.34.34.319.000 4.34.34.34.34.319.500 4.44.44.34.34.320.000 4.44.44.44.44.420.500 4.44.44.44.44.421.000 4.44.44.44.44.421.500 4.44.44.44.44.422.000 4.54.54.44.44.422.500 4.54.54.54.54.523.000 4.54.54.54.54.523.500

(N/A)(N/A)(N/A)(N/A)4.524.000

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PondPack CONNECT Edition [10.02.00.01]

Scenario: Post-Development 100 year Storm Event: 100 yearLabel: MSE4

Return Event: 100 yearsSubsection: Time-Depth Curve

Time-Depth Curve: 100 year

100 year Label hours0.000Start Time hours0.100Increment hours24.000End Time years100Return Event

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

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

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

0.00.00.00.00.00.000 0.00.00.00.00.00.500 0.10.10.00.00.01.000 0.10.10.10.10.11.500 0.10.10.10.10.12.000 0.20.10.10.10.12.500 0.20.20.20.20.23.000 0.20.20.20.20.23.500 0.30.30.30.30.24.000 0.30.30.30.30.34.500 0.40.40.40.40.35.000 0.40.40.40.40.45.500 0.50.50.50.50.56.000 0.60.60.60.50.56.500 0.60.60.60.60.67.000 0.70.70.70.70.77.500 0.80.80.80.80.78.000 0.90.90.90.80.88.500 1.01.01.00.90.99.000 1.21.11.11.11.09.500 1.31.31.21.21.210.000 1.61.51.41.41.310.500 1.91.81.81.71.611.000 2.92.62.32.22.011.500 5.35.14.94.63.512.000 5.85.75.65.55.412.500 6.16.06.05.95.913.000 6.36.26.26.26.113.500 6.46.46.46.36.314.000 6.56.56.56.56.414.500 6.66.66.66.66.615.000 6.76.76.76.76.715.500 6.86.86.86.86.716.000 6.96.96.86.86.816.500

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PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: MSE4

Return Event: 100 yearsSubsection: Time-Depth Curve

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

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

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

6.96.96.96.96.917.000 7.07.07.07.07.017.500 7.17.17.07.07.018.000 7.17.17.17.17.118.500 7.27.27.27.17.119.000 7.27.27.27.27.219.500 7.37.37.37.27.220.000 7.37.37.37.37.320.500 7.47.37.37.37.321.000 7.47.47.47.47.421.500 7.47.47.47.47.422.000 7.47.47.47.47.422.500 7.57.57.57.47.423.000 7.57.57.57.57.523.500

(N/A)(N/A)(N/A)(N/A)7.524.000

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PondPack CONNECT Edition [10.02.00.01]

Scenario: Post-Development 25 year Storm Event: 25 yearLabel: MSE4

Return Event: 25 yearsSubsection: Time-Depth Curve

Time-Depth Curve: 25 year

25 year Label hours0.000Start Time hours0.100Increment hours24.000End Time years25Return Event

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

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

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

0.00.00.00.00.00.000 0.00.00.00.00.00.500 0.00.00.00.00.01.000 0.10.10.10.00.01.500 0.10.10.10.10.12.000 0.10.10.10.10.12.500 0.10.10.10.10.13.000 0.20.20.20.20.13.500 0.20.20.20.20.24.000 0.20.20.20.20.24.500 0.30.30.30.30.35.000 0.30.30.30.30.35.500 0.40.40.40.40.36.000 0.40.40.40.40.46.500 0.50.50.50.50.47.000 0.50.50.50.50.57.500 0.60.60.60.60.68.000 0.70.60.60.60.68.500 0.80.70.70.70.79.000 0.90.80.80.80.89.500 1.00.90.90.90.910.000 1.21.11.11.01.010.500 1.41.41.31.31.211.000 2.21.91.71.61.511.500 4.03.83.73.42.612.000 4.34.24.24.14.112.500 4.54.54.54.44.413.000 4.74.64.64.64.613.500 4.84.74.74.74.714.000 4.94.84.84.84.814.500 4.94.94.94.94.915.000 5.05.05.05.04.915.500 5.15.05.05.05.016.000 5.15.15.15.15.116.500

Page 7 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 25 yearLabel: MSE4

Return Event: 25 yearsSubsection: Time-Depth Curve

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

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

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

5.25.25.15.15.117.000 5.25.25.25.25.217.500 5.35.25.25.25.218.000 5.35.35.35.35.318.500 5.35.35.35.35.319.000 5.45.45.45.45.319.500 5.45.45.45.45.420.000 5.45.45.45.45.420.500 5.55.55.55.45.421.000 5.55.55.55.55.521.500 5.55.55.55.55.522.000 5.55.55.55.55.522.500 5.55.55.55.55.523.000 5.65.65.65.65.523.500

(N/A)(N/A)(N/A)(N/A)5.624.000

Page 8 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Scenario: Post-Development 50 year Storm Event: 50 yearLabel: MSE4

Return Event: 50 yearsSubsection: Time-Depth Curve

Time-Depth Curve: 50 year

50 year Label hours0.000Start Time hours0.100Increment hours24.000End Time years50Return Event

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

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

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

0.00.00.00.00.00.000 0.00.00.00.00.00.500 0.00.00.00.00.01.000 0.10.10.10.10.11.500 0.10.10.10.10.12.000 0.10.10.10.10.12.500 0.20.20.20.10.13.000 0.20.20.20.20.23.500 0.20.20.20.20.24.000 0.30.30.30.30.34.500 0.30.30.30.30.35.000 0.40.40.40.40.35.500 0.40.40.40.40.46.000 0.50.50.50.50.56.500 0.60.60.50.50.57.000 0.60.60.60.60.67.500 0.70.70.70.70.68.000 0.80.80.70.70.78.500 0.90.90.80.80.89.000 1.01.01.00.90.99.500 1.11.11.11.11.010.000 1.31.31.21.21.210.500 1.71.61.51.51.411.000 2.52.22.01.91.811.500 4.64.54.34.03.012.000 5.04.94.94.84.712.500 5.35.25.25.15.113.000 5.45.45.45.35.313.500 5.65.55.55.55.514.000 5.75.65.65.65.614.500 5.85.75.75.75.715.000 5.85.85.85.85.815.500 5.95.95.95.95.816.000 6.05.95.95.95.916.500

Page 9 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 50 yearLabel: MSE4

Return Event: 50 yearsSubsection: Time-Depth Curve

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

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

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

6.06.06.06.06.017.000 6.16.16.06.06.017.500 6.16.16.16.16.118.000 6.26.26.26.16.118.500 6.26.26.26.26.219.000 6.36.36.26.26.219.500 6.36.36.36.36.320.000 6.36.36.36.36.320.500 6.46.46.46.36.321.000 6.46.46.46.46.421.500 6.46.46.46.46.422.000 6.46.46.46.46.422.500 6.56.56.56.56.423.000 6.56.56.56.56.523.500

(N/A)(N/A)(N/A)(N/A)6.524.000

Page 10 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: East Ditch DA

Return Event: 100 yearsSubsection: Time of Concentration Calculations

Time of Concentration Results

Segment #1: SCS Lag ft1,136.78Hydraulic Length

74.000CN

ft/ft0.037Slope ft/s0.87Average Velocity hours0.364 Segment Time of Concentration

Time of Concentration (Composite) hours0.364 Time of Concentration (Composite)

Page 11 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: East Ditch DA

Return Event: 100 yearsSubsection: Time of Concentration Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.5)Tc = Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

Page 12 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: Existing Basin DA

Return Event: 100 yearsSubsection: Time of Concentration Calculations

Time of Concentration Results

Segment #1: SCS Lag ft4,600.00Hydraulic Length

79.000CN

ft/ft0.016Slope ft/s0.86Average Velocity hours1.480 Segment Time of Concentration

Time of Concentration (Composite) hours1.480 Time of Concentration (Composite)

Page 13 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: Existing Basin DA

Return Event: 100 yearsSubsection: Time of Concentration Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.5)Tc = Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

Page 14 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: East Ditch DA

Return Event: 100 yearsSubsection: Runoff CN-Area

Runoff Curve Number Data

Adjusted CNUC

C

Area (ft²)

CNSoil/Surface Description

82.0000.00.0115,758.182.000Row crops - SR + Crop residue, good - Soil C

74.0000.00.057,707.274.000Pasture, grassland, or range - good - Soil C

89.0000.00.023,985.489.000Impervious Areas - Gravel (w/ right-of-way) - Soil C

80.512(N/A)(N/A)197,450.7(N/A)COMPOSITE AREA & WEIGHTED CN --->

Page 15 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: Existing Basin DA

Return Event: 100 yearsSubsection: Runoff CN-Area

Runoff Curve Number Data

Adjusted CNUC

C

Area (ft²)

CNSoil/Surface Description

82.0000.00.06,232,307.782.000Row crops - SR + Crop residue, good - Soil C

77.0000.00.0494,523.977.000Residential Districts - 2 acre - Soil C 74.0000.00.02,023,116.074.000Pasture, grassland, or range - good - Soil

C 72.0000.00.090,483.672.000Woods - grass combination - good - Soil C 74.0000.00.0546,361.274.000Pasture, grassland, or range - good - Soil

C 89.0000.00.0162,250.589.000Impervious Areas - Gravel (w/ right-of-way) - Soil C 75.0000.00.02,670,989.075.000Row crops - SR + Crop residue, good -

Soil B

78.604(N/A)(N/A)12,220,031.9(N/A)COMPOSITE AREA & WEIGHTED CN --->

Page 16 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 10 yearLabel: East Ditch DA

Return Event: 10 yearsSubsection: Unit Hydrograph Summary

10 yearStorm Event years10Return Event hours24.000Duration in4.5Depth hours0.364 Time of Concentration (Composite) ft²197,450.7Area (User Defined) hours0.049 Computational Time Increment hours12.244Time to Peak (Computed) ft³/s10.89Flow (Peak, Computed) hours0.100Output Increment hours12.300 Time to Flow (Peak Interpolated Output) ft³/s10.79 Flow (Peak Interpolated Output)

Drainage Area

81.000SCS CN (Composite) ft²197,450.7Area (User Defined) in2.3 Maximum Retention (Pervious) in0.5 Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in2.5 Cumulative Runoff Depth (Pervious) ac-ft0.956Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft0.954Volume

SCS Unit Hydrograph Parameters hours0.364 Time of Concentration (Composite) hours0.049 Computational Time Increment

483.432 Unit Hydrograph Shape Factor

0.749K Factor

1.670Receding/Rising, Tr/Tp

Page 17 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 10 yearLabel: East Ditch DA

Return Event: 10 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s14.09Unit peak, qp hours0.243Unit peak time, Tp hours0.972Unit receding limb, Tr hours1.215Total unit time, Tb

Page 18 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 25 yearLabel: East Ditch DA

Return Event: 25 yearsSubsection: Unit Hydrograph Summary

25 yearStorm Event years25Return Event hours24.000Duration in5.6Depth hours0.364 Time of Concentration (Composite) ft²197,450.7Area (User Defined) hours0.049 Computational Time Increment hours12.244Time to Peak (Computed) ft³/s14.98Flow (Peak, Computed) hours0.100Output Increment hours12.300 Time to Flow (Peak Interpolated Output) ft³/s14.76 Flow (Peak Interpolated Output)

Drainage Area

81.000SCS CN (Composite) ft²197,450.7Area (User Defined) in2.3 Maximum Retention (Pervious) in0.5 Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in3.5 Cumulative Runoff Depth (Pervious) ac-ft1.316Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft1.314Volume

SCS Unit Hydrograph Parameters hours0.364 Time of Concentration (Composite) hours0.049 Computational Time Increment

483.432 Unit Hydrograph Shape Factor

0.749K Factor

1.670Receding/Rising, Tr/Tp

Page 19 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 25 yearLabel: East Ditch DA

Return Event: 25 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s14.09Unit peak, qp hours0.243Unit peak time, Tp hours0.972Unit receding limb, Tr hours1.215Total unit time, Tb

Page 20 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 50 yearLabel: East Ditch DA

Return Event: 50 yearsSubsection: Unit Hydrograph Summary

50 yearStorm Event years50Return Event hours24.000Duration in6.5Depth hours0.364 Time of Concentration (Composite) ft²197,450.7Area (User Defined) hours0.049 Computational Time Increment hours12.244Time to Peak (Computed) ft³/s18.52Flow (Peak, Computed) hours0.100Output Increment hours12.300 Time to Flow (Peak Interpolated Output) ft³/s18.18 Flow (Peak Interpolated Output)

Drainage Area

81.000SCS CN (Composite) ft²197,450.7Area (User Defined) in2.3 Maximum Retention (Pervious) in0.5 Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in4.3 Cumulative Runoff Depth (Pervious) ac-ft1.633Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft1.631Volume

SCS Unit Hydrograph Parameters hours0.364 Time of Concentration (Composite) hours0.049 Computational Time Increment

483.432 Unit Hydrograph Shape Factor

0.749K Factor

1.670Receding/Rising, Tr/Tp

Page 21 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 50 yearLabel: East Ditch DA

Return Event: 50 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s14.09Unit peak, qp hours0.243Unit peak time, Tp hours0.972Unit receding limb, Tr hours1.215Total unit time, Tb

Page 22 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: East Ditch DA

Return Event: 100 yearsSubsection: Unit Hydrograph Summary

100 yearStorm Event years100Return Event hours24.000Duration in7.5Depth hours0.364 Time of Concentration (Composite) ft²197,450.7Area (User Defined) hours0.049 Computational Time Increment hours12.244Time to Peak (Computed) ft³/s22.39Flow (Peak, Computed) hours0.100Output Increment hours12.300 Time to Flow (Peak Interpolated Output) ft³/s21.92 Flow (Peak Interpolated Output)

Drainage Area

81.000SCS CN (Composite) ft²197,450.7Area (User Defined) in2.3 Maximum Retention (Pervious) in0.5 Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in5.3 Cumulative Runoff Depth (Pervious) ac-ft1.984Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft1.981Volume

SCS Unit Hydrograph Parameters hours0.364 Time of Concentration (Composite) hours0.049 Computational Time Increment

483.432 Unit Hydrograph Shape Factor

0.749K Factor

1.670Receding/Rising, Tr/Tp

Page 23 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: East Ditch DA

Return Event: 100 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s14.09Unit peak, qp hours0.243Unit peak time, Tp hours0.972Unit receding limb, Tr hours1.215Total unit time, Tb

Page 24 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 10 yearLabel: Existing Basin DA

Return Event: 10 yearsSubsection: Unit Hydrograph Summary

10 yearStorm Event years10Return Event hours24.000Duration in4.5Depth hours1.480 Time of Concentration (Composite) ft²12,220,031.9Area (User Defined) hours0.197 Computational Time Increment hours13.023Time to Peak (Computed) ft³/s267.20Flow (Peak, Computed) hours0.100Output Increment hours13.000 Time to Flow (Peak Interpolated Output) ft³/s265.71 Flow (Peak Interpolated Output)

Drainage Area

79.000SCS CN (Composite) ft²12,220,031.9Area (User Defined) in2.7 Maximum Retention (Pervious) in0.5 Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in2.4 Cumulative Runoff Depth (Pervious) ac-ft55.164Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft54.597Volume

SCS Unit Hydrograph Parameters hours1.480 Time of Concentration (Composite) hours0.197 Computational Time Increment

483.432 Unit Hydrograph Shape Factor

0.749K Factor

1.670Receding/Rising, Tr/Tp

Page 25 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 10 yearLabel: Existing Basin DA

Return Event: 10 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s214.78Unit peak, qp hours0.987Unit peak time, Tp hours3.946Unit receding limb, Tr hours4.933Total unit time, Tb

Page 26 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 25 yearLabel: Existing Basin DA

Return Event: 25 yearsSubsection: Unit Hydrograph Summary

25 yearStorm Event years25Return Event hours24.000Duration in5.6Depth hours1.480 Time of Concentration (Composite) ft²12,220,031.9Area (User Defined) hours0.197 Computational Time Increment hours13.023Time to Peak (Computed) ft³/s373.98Flow (Peak, Computed) hours0.100Output Increment hours13.000 Time to Flow (Peak Interpolated Output) ft³/s372.29 Flow (Peak Interpolated Output)

Drainage Area

79.000SCS CN (Composite) ft²12,220,031.9Area (User Defined) in2.7 Maximum Retention (Pervious) in0.5 Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in3.3 Cumulative Runoff Depth (Pervious) ac-ft76.899Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft76.159Volume

SCS Unit Hydrograph Parameters hours1.480 Time of Concentration (Composite) hours0.197 Computational Time Increment

483.432 Unit Hydrograph Shape Factor

0.749K Factor

1.670Receding/Rising, Tr/Tp

Page 27 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 25 yearLabel: Existing Basin DA

Return Event: 25 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s214.78Unit peak, qp hours0.987Unit peak time, Tp hours3.946Unit receding limb, Tr hours4.933Total unit time, Tb

Page 28 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 50 yearLabel: Existing Basin DA

Return Event: 50 yearsSubsection: Unit Hydrograph Summary

50 yearStorm Event years50Return Event hours24.000Duration in6.5Depth hours1.480 Time of Concentration (Composite) ft²12,220,031.9Area (User Defined) hours0.197 Computational Time Increment hours13.023Time to Peak (Computed) ft³/s467.17Flow (Peak, Computed) hours0.100Output Increment hours13.000 Time to Flow (Peak Interpolated Output) ft³/s465.33 Flow (Peak Interpolated Output)

Drainage Area

79.000SCS CN (Composite) ft²12,220,031.9Area (User Defined) in2.7 Maximum Retention (Pervious) in0.5 Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in4.1 Cumulative Runoff Depth (Pervious) ac-ft96.109Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft95.222Volume

SCS Unit Hydrograph Parameters hours1.480 Time of Concentration (Composite) hours0.197 Computational Time Increment

483.432 Unit Hydrograph Shape Factor

0.749K Factor

1.670Receding/Rising, Tr/Tp

Page 29 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 50 yearLabel: Existing Basin DA

Return Event: 50 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s214.78Unit peak, qp hours0.987Unit peak time, Tp hours3.946Unit receding limb, Tr hours4.933Total unit time, Tb

Page 30 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: Existing Basin DA

Return Event: 100 yearsSubsection: Unit Hydrograph Summary

100 yearStorm Event years100Return Event hours24.000Duration in7.5Depth hours1.480 Time of Concentration (Composite) ft²12,220,031.9Area (User Defined) hours0.197 Computational Time Increment hours13.023Time to Peak (Computed) ft³/s569.71Flow (Peak, Computed) hours0.100Output Increment hours13.000 Time to Flow (Peak Interpolated Output) ft³/s567.75 Flow (Peak Interpolated Output)

Drainage Area

79.000SCS CN (Composite) ft²12,220,031.9Area (User Defined) in2.7 Maximum Retention (Pervious) in0.5 Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in5.0 Cumulative Runoff Depth (Pervious) ac-ft117.489Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft116.443Volume

SCS Unit Hydrograph Parameters hours1.480 Time of Concentration (Composite) hours0.197 Computational Time Increment

483.432 Unit Hydrograph Shape Factor

0.749K Factor

1.670Receding/Rising, Tr/Tp

Page 31 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 100 yearLabel: Existing Basin DA

Return Event: 100 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s214.78Unit peak, qp hours0.987Unit peak time, Tp hours3.946Unit receding limb, Tr hours4.933Total unit time, Tb

Page 32 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 10 yearLabel: Existing Basin (OUT)

Return Event: 10 yearsSubsection: Time vs. Elevation

Time vs. Elevation (ft)

Output Time increment = 0.100 hours Time on left represents time for first value in each row.

Elevation (ft)

Elevation (ft)

Elevation (ft)

Elevation (ft)

Elevation (ft)

Time (hours)

1,147.101,147.101,147.101,147.101,147.100.000 1,147.101,147.101,147.101,147.101,147.100.500 1,147.101,147.101,147.101,147.101,147.101.000 1,147.101,147.101,147.101,147.101,147.101.500 1,147.101,147.101,147.101,147.101,147.102.000 1,147.101,147.101,147.101,147.101,147.102.500 1,147.101,147.101,147.101,147.101,147.103.000 1,147.101,147.101,147.101,147.101,147.103.500 1,147.101,147.101,147.101,147.101,147.104.000 1,147.101,147.101,147.101,147.101,147.104.500 1,147.101,147.101,147.101,147.101,147.105.000 1,147.101,147.101,147.101,147.101,147.105.500 1,147.101,147.101,147.101,147.101,147.106.000 1,147.101,147.101,147.101,147.101,147.106.500 1,147.101,147.101,147.101,147.101,147.107.000 1,147.101,147.101,147.101,147.101,147.107.500 1,147.101,147.101,147.101,147.101,147.108.000 1,147.101,147.101,147.101,147.101,147.108.500 1,147.121,147.111,147.111,147.101,147.109.000 1,147.231,147.201,147.171,147.151,147.139.500 1,147.511,147.441,147.381,147.321,147.2710.000 1,147.801,147.731,147.681,147.631,147.5910.500 1,148.301,148.181,148.071,147.961,147.8711.000 1,149.321,149.001,148.781,148.601,148.4311.500 1,151.851,151.301,150.751,150.301,149.7612.000 1,154.231,153.811,153.361,152.881,152.3712.500 1,155.471,155.341,155.161,154.911,154.6013.000 1,155.251,155.391,155.481,155.531,155.5313.500 1,154.041,154.361,154.641,154.871,155.0914.000 1,152.011,152.431,152.851,153.271,153.6714.500 1,150.291,150.531,150.811,151.181,151.5915.000 1,149.631,149.721,149.811,149.911,150.0715.500 1,149.251,149.311,149.391,149.461,149.5516.000 1,149.011,149.051,149.101,149.141,149.1916.500 1,148.881,148.901,148.921,148.951,148.9817.000 1,148.791,148.811,148.831,148.841,148.8617.500 1,148.731,148.741,148.751,148.771,148.7818.000 1,148.671,148.681,148.691,148.701,148.7118.500 1,148.611,148.621,148.631,148.641,148.6519.000 1,148.541,148.551,148.571,148.581,148.6019.500

Page 33 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 10 yearLabel: Existing Basin (OUT)

Return Event: 10 yearsSubsection: Time vs. Elevation

Time vs. Elevation (ft)

Output Time increment = 0.100 hours Time on left represents time for first value in each row.

Elevation (ft)

Elevation (ft)

Elevation (ft)

Elevation (ft)

Elevation (ft)

Time (hours)

1,148.471,148.491,148.501,148.511,148.5320.000 1,148.401,148.421,148.431,148.441,148.4620.500 1,148.331,148.351,148.361,148.371,148.3921.000 1,148.261,148.281,148.291,148.301,148.3221.500 1,148.191,148.211,148.221,148.231,148.2522.000 1,148.121,148.141,148.151,148.161,148.1822.500 1,148.041,148.051,148.071,148.091,148.1123.000 1,147.941,147.961,147.981,148.001,148.0223.500

(N/A)(N/A)(N/A)(N/A)1,147.9224.000

Page 34 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 25 yearLabel: Existing Basin (OUT)

Return Event: 25 yearsSubsection: Time vs. Elevation

Time vs. Elevation (ft)

Output Time increment = 0.100 hours Time on left represents time for first value in each row.

Elevation (ft)

Elevation (ft)

Elevation (ft)

Elevation (ft)

Elevation (ft)

Time (hours)

1,147.101,147.101,147.101,147.101,147.100.000 1,147.101,147.101,147.101,147.101,147.100.500 1,147.101,147.101,147.101,147.101,147.101.000 1,147.101,147.101,147.101,147.101,147.101.500 1,147.101,147.101,147.101,147.101,147.102.000 1,147.101,147.101,147.101,147.101,147.102.500 1,147.101,147.101,147.101,147.101,147.103.000 1,147.101,147.101,147.101,147.101,147.103.500 1,147.101,147.101,147.101,147.101,147.104.000 1,147.101,147.101,147.101,147.101,147.104.500 1,147.101,147.101,147.101,147.101,147.105.000 1,147.101,147.101,147.101,147.101,147.105.500 1,147.101,147.101,147.101,147.101,147.106.000 1,147.101,147.101,147.101,147.101,147.106.500 1,147.101,147.101,147.101,147.101,147.107.000 1,147.101,147.101,147.101,147.101,147.107.500 1,147.121,147.111,147.111,147.111,147.108.000 1,147.191,147.171,147.151,147.141,147.138.500 1,147.391,147.341,147.291,147.251,147.229.000 1,147.691,147.641,147.601,147.521,147.459.500 1,147.971,147.911,147.851,147.791,147.7410.000 1,148.311,148.231,148.161,148.101,148.0410.500 1,148.931,148.771,148.641,148.511,148.4011.000 1,150.211,149.811,149.531,149.291,149.1111.500 1,152.781,152.181,151.591,151.001,150.5212.000 1,155.671,155.151,154.581,153.981,153.3812.500 1,156.771,156.771,156.691,156.471,156.1213.000 1,156.401,156.511,156.601,156.671,156.7313.500 1,155.601,155.811,155.991,156.141,156.2714.000 1,154.111,154.471,154.791,155.091,155.3514.500 1,151.981,152.411,152.841,153.281,153.7115.000 1,150.321,150.561,150.831,151.181,151.5815.500 1,149.681,149.761,149.841,149.941,150.1216.000 1,149.391,149.431,149.491,149.551,149.6116.500 1,149.231,149.251,149.281,149.311,149.3417.000 1,149.131,149.151,149.171,149.191,149.2117.500 1,149.041,149.061,149.081,149.101,149.1118.000 1,148.961,148.981,149.001,149.011,149.0318.500 1,148.891,148.901,148.921,148.931,148.9519.000 1,148.811,148.831,148.841,148.861,148.8719.500

Page 35 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 25 yearLabel: Existing Basin (OUT)

Return Event: 25 yearsSubsection: Time vs. Elevation

Time vs. Elevation (ft)

Output Time increment = 0.100 hours Time on left represents time for first value in each row.

Elevation (ft)

Elevation (ft)

Elevation (ft)

Elevation (ft)

Elevation (ft)

Time (hours)

1,148.731,148.751,148.761,148.781,148.7920.000 1,148.661,148.671,148.691,148.701,148.7220.500 1,148.581,148.601,148.611,148.631,148.6421.000 1,148.491,148.501,148.521,148.541,148.5621.500 1,148.391,148.411,148.431,148.451,148.4722.000 1,148.301,148.321,148.341,148.361,148.3722.500 1,148.211,148.231,148.251,148.261,148.2823.000 1,148.121,148.131,148.151,148.171,148.1923.500

(N/A)(N/A)(N/A)(N/A)1,148.1024.000

Page 36 of 7427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

9/19/2025

PondPack CONNECT Edition [10.02.00.01]

Storm Event: 50 yearLabel: Existing Basin (OUT)

Return Event: 50 yearsSubsection: Time vs. Elevation

Time vs. Elevation (ft)

Output Time increment = 0.100 hours Time on left represents time for first value in each row.

Elevation (ft)

Elevation (ft)

Elevation (ft)

Elevation (ft)

Elevation (ft)

Time (hours)

1,147.101,147.101,147.101,147.101,147.100.000 1,147.101,147.101,147.101,147.101,147.100.500 1,147.101,147.101,147.101,147.101,147.101.000 1,147.101,147.101,147.101,147.101,147.101.500 1,147.101,147.101,147.101,147.101,147.102.000 1,147.101,147.101,147.101,147.101,147.102.500 1,147.101,147.101,147.101,147.101,147.103.000 1,147.101,147.101,147.101,147.101,147.103.500 1,147.101,147.101,147.101,147.101,147.104.000 1,147.101,147.101,147.101,147.101,147.104.500 1,147.101,147.101,147.101,147.101,147.105.000 1,147.101,147.101,147.101,147.101,147.105.500 1,147.101,147.101,147.101,147.101,147.106.000 1,147.101,147.101,147.101,147.101,147.106.500 1,147.111,147.101,147.101,147.101,147.107.000 1,147.141,147.131,147.121,147.111,147.117.500 1,147.271,147.231,147.201,147.181,147.168.000 1,147.501,147.441,147.401,147.351,147.318.500 1,147.721,147.671,147.641,147.611,147.559.000 1,148.011,147.941,147.871,147.821,147.769.500 1,148.341,148.271,148.211,148.151,148.0810.000 1,148.721,148.631,148.551,148.471,148.4010.500 1,149.441,149.261,149.101,148.951,148.8311.000 1,150.671,150.361,150.141,149.871,149.6511.500 1,153.491,152.831,152.201,151.611,151.1012.000 1,156.661,156.151,155.521,154.841,154.1612.500 1,157.051,157.101,157.111,157.081,156.9613.000 1,156.631,156.711,156.801,156.891,156.9713.500 1,156.031,156.181,156.311,156.431,156.5414.000 1,154.891,155.171,155.421,155.661,155.8614.500 1,153.101,153.501,153.891,154.261,154.5915.000 1,151.151,151.501,151.881,152.271,152.6815.500 1,150.021,150.221,150.371,150.591,150.8316.000 1,149.681,149.731,149.791,149.861,149.9316.500…