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RVBC civil rpt SWMP_01-27-'26
STORMWATER MANAGEMENT PLAN RIVER VALLEY BUSINESS CENTER CHANHASSEN, MN DATE:01-27-2026 CMI PROJECT NO.:23089 PREPARED FOR: Cornerstone Investors, LLC PREPARED BY: Civil Methods, Inc. PO Box 28038 St. Paul, MN 55128 ENGINEER CERTIFICATION: I hereby certify that this plan, specification, or report was prepared by me or under my direct supervision and that I am a duly licensed Professional Engineer under the laws of the State of Minnesota. Name:David Poggi, PE Signed: Date:01-27-2026 Registration: MN No. 44573 River Valley Business Center – SWMP January 2026 Civil Methods, Inc.Page | i Table of Contents 1.INTRODUCTION ............................................................................................................................................. 2 2.EXISTING SITE CONDITIONS ........................................................................................................................... 2 3.PROPOSED SITE CONDITIONS ........................................................................................................................ 3 4.STORMWATER MANAGEMENT REQUIREMENTS ........................................................................................... 3 4.1 VOLUME CONTROL &WQV TREATMENT ......................................................................................................... 3 4.2 RUNOFF RATE CONTROL .............................................................................................................................. 4 4.3 BASIN ELEVATIONS ...................................................................................................................................... 4 4.4 BASIN PRETREATMENT ................................................................................................................................. 4 APPENDIX A – SOILS INFORMATION APPENDIX B – DRAINAGE DIAGRAMS APPENDIX C –HYDROCAD REPORT 1.INTRODUCTION The River Valley Business Center project includes the construction of a new storage yard at 2100 Stoughton Ave in Chanhassen, MN. This Stormwater Management Plan (SWMP) addresses the grading and management practices necessary to mitigate the stormwater-related impacts of the project. Governmental agencies with jurisdiction over drainage and stormwater for this project include: ·City of Chanhassen; City of Chaska ·Lower Minnesota River WMO (LMRWMO) ·Minnesota Pollution Control Agency (MPCA) Where needed, site conditions have been modeled with the HydroCAD modeling software using the TR-20 methodology and Atlas 14 design rainfall amounts. Applicability ·Project requires an NPDES/SDS Permit because more than 1 acre of land is disturbed. ·Project is generally subject to the City and Watershed standards. Regulatory Stormwater Requirements: 1)Rate control for the 2-, 10-, and 100-year design rainfall events. 2)Provide volume control for 1.0” of runoff from new impervious area. 3)No increase in TSS and TP. 4)Building Elevations: a.Lowest floor shall be at least 2.0’ above basin HWL and 1.0’ above EOF. 2.EXISTING SITE CONDITIONS The current 6.4 acre site consists of industrial yard, pavements and agricultural use, with grass near street right of way. No wetlands exist onsite. Soil mapping for the area indicates a prevalence of Hydrologic Soil Group (HSG) Type A soils of high infiltration capacity; this condition has been verified with a geotechnical investigation (Appendix A). Based on the recommendations of the Minnesota Stormwater Manual, a suitable estimate of infiltration rate for Type A soils is 1.0 IN/HR. Stormwater runoff drainage from the site is split, with the northern portion of the site discharging north and east, and the southern portion of the site draining south into the storm sewer at the southwest corner of the property and ultimately to the street system (Appendix B). Geotechnical borings were recovered to a depth of 21 FT (roughly elevation = 736), and no groundwater was present. 3.PROPOSED SITE CONDITIONS The proposed conditions include a new parking and storage area, along with site grading and stormwater infiltration basins. Approximately 4.20 acres of new or reconstructed impervious cover (2.94 acres of net new impervious) will be added to the site. Infiltration basins and swales will be graded for stormwater management. In general, post-construction drainage patterns will remain similar to existing conditions (Appendix B). 4.STORMWATER MANAGEMENT REQUIREMENTS 4.1 VOLUME CONTROL &WQV TREATMENT The proposed project will include 4.20 acres (183,067 SF) of new or reconstructed impervious area subject to the water quality standards of the City and LMRWD. An additional 0.20 acres of offsite impervious area (Stoughton Ave) will drain to Basin 1 and is included in the modeling described in section 4.2. The water quality volume (WQV) of 1.0 IN of runoff from the 183,067 SF shall be retained/infiltrated onsite, resulting in a required infiltration volume of 15,256 CF. The total infiltration volume provided in the designed basins (volume below outlet elevation) is 46,579 CF; Table 4.1 summarizes the breakdown for each subcatchment. Table 4.1: Basin Infiltration Volumes: Drawdown of water levels in infiltration basins must occur within 48 hours. Using an infiltration rate of 1.0 IN/HR, the maximum basin depth below outlet elevation is 4.0 FT. The proposed infiltration basins are all designed with a depth to outlet elevation of 2.5 FT or less, depending (see plan). Since the project meets or exceeds the volume control standards for the site, it will inherently meet the TSS and TP standards of no annual increase. Basin or Area ID Regulatory Impervious Area (SF) Infiltration WQV Req'd (IN) Iniltration WQV Req'd (CF) WQV Prov'd (CF) Basin 1 (1in)107073 1.0 8923 26625 Basin 2 (2in)44257 1.0 3688 19954 Area 3 31737 1.0 2645 0 TOTAL:183067 15256 46579 4.2 RUNOFF RATE CONTROL The proposed development shall not increase the existing runoff discharge rate from the site for the 2-, 10-, and 100-year design storms. The pre- and post-construction conditions have been modeled for these rainfall scenarios using the HydroCAD stormwater modeling program. Table 4.2 summarizes the pre- and post-construction discharge rates from each subcatchment, as well as the entire property. A detailed HydroCAD report is included in Appendix C. Table 4.2: Discharge Summary The discharge flow rate in the proposed construction condition is at or below that of the existing condition for the entire site, as well as at each discharge location. 4.3 BASIN ELEVATIONS Floor separation requirements include low floor separation of 2’ from basin HWL. The existing building low floor elevation is approximately 760.0 The following table summarizes basin elevations and related regulatory structure elevations: Table 4.3: Basin and Regulatory Elevations 4.4 BASIN PRETREATMENT No new storm sewer is proposed and runoff will drain to infiltration basins via overland flow (no direct storm sewer drainage from impervious area to infiltration basin). Pretreatment will occur in the grass swales prior to entering the infiltration basins. To ensure adequate grass area for filtration, the calculation outlined in the MN Stormwater Manual for Pretreatment Filter Strip sizing has been used for each basin. Pretreatment sizing is a function of the tributary Area / Node ID Existing (cfs) Proposed (cfs) Existing (cfs) Proposed (cfs) Existing (cfs) Proposed (cfs) E1/P1 1.7 0.0 2.5 0.0 5.3 2.3 E2/P2 0.0 0.0 0.0 0.0 0.0 0.0 E3/P3 3.1 3.1 4.9 4.6 9.0 7.8 R1 3.9 3.1 6.0 4.6 10.9 7.8 2-Year 10-Year 100-Year Basin ID GWL / Redox Bottom Elev.* Outlet Elev.100-Yr HWL EOF (ft, MSL) Lowest Allowable Floor Elev. Basin 1IN <736 752.00 754.50 755.55 755.60 757.55 Basin 2IN <736 754.00 856.20 756.11 756.20 758.11 *3.0' minimum separation required from seasonal high GWL to basin bottom elev. impervious area, as well as typical values for removal fraction (50%) and peak intensity (0.5 in/hr). The following table summarizes minimum filter strip areas for the entire impervious area tributary to each basin, which are substantially exceeded with the proposed plan: Table 4.4: Pretreatment Filter Strip Area Basin ID Minimum Filter Strip Size (SF) Basin 1IN 39 Basin 2IN 15 Appendix A – Soils Information Hydrologic Soil Group—Carver County, Minnesota Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 1/5/2026 Page 1 of 4496086049609304961000496107049611404961210496128049613504961420496086049609304961000496107049611404961210496128049613504961420454260454330454400454470454540454610454680 454260 454330 454400 454470 454540 454610 454680 44° 48' 17'' N 93° 34' 43'' W44° 48' 17'' N93° 34' 21'' W44° 47' 57'' N 93° 34' 43'' W44° 47' 57'' N 93° 34' 21'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 15N WGS84 0 100 200 400 600 Feet 0 40 80 160 240 Meters Map Scale: 1:3,000 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) 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. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation 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: Carver County, Minnesota Survey Area Data: Version 22, Sep 9, 2025 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jun 29, 2023—Sep 13, 2023 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—Carver County, Minnesota Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 1/5/2026 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI MN Minneiska loam B 1.8 8.7% PA Sparta loamy sand, 0 to 2 percent slopes A 15.0 70.6% PB Sparta loamy sand, 2 to 6 percent slopes A 3.4 15.9% PC Sparta loamy sand, 6 to 12 percent slopes A 1.0 4.9% Totals for Area of Interest 21.3 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Hydrologic Soil Group—Carver County, Minnesota Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 1/5/2026 Page 3 of 4 ____________________________________________________________________________________________ La Crosse, WI St. Cloud, MN Mankato, MN Rochester, MN Chosen Valley Testing, Inc. Geotechnical Engineering and Testing • 1410 7th St. NW • Rochester, MN 55901 • Telephone (507) 281-0968• Fax (507) 289-2523 Mr. Joel Buttenhoff June 28, 2007 5th Street Ventures 21000 Highway 7 Excelsior, MN 55331 Re: Design Phase Geotechnical Services Proposed Gedney Property Development 2100 Stoughton Ave. Chaska, Minnesota CVT Project Number: R2007.163 Dear Mr. Buttenhoff: We have completed the drilling and geotechnical evaluation for the proposed development of the Gedney property in Chaska, Minnesota. This brief letter summarizes the findings in the attached report. Summary of Findings The southwestern borings encountered about 1½ feet of aggregate base at the surface. The other borings encountered about 1½ feet of topsoil. Outwash sands were the dominant soils encountered below the topsoil. Fine sands were often encountered below the topsoil or aggregate, and extended to depths of about 4 to 12 feet. Silty sands were met below the surfacial materials in five of the west/northwest borings. Some of these soils had the appearance of possible fill. At depth all of the borings were dominated by medium to coarse sand, often containing gravel, which was met until the termination depths at about 21 feet. Free water was not observed in any of the boreholes and the majority of the samples were only moist. Based on the findings, it appears that the static groundwater level in the areas of exploration is below the depths explored. The upper silty sands were often wet, likely due to water perching in these soils. Summary of Analysis and Recommendations We recommend stripping the topsoil and aggregate base from below the building and oversize areas. These soils were about 1½ feet deep. Most of the borings to the north and northeast encountered loose sands below the topsoil. The far southern borings encountered similar sands. These sands were relatively clean and would respond well to surface compaction. We recommend surface compacting the sands present at footing grade. This can likely be accomplished with turtle-type compactor. The uppermost soils in the northwest borings and those near Highway 212 were very loose to loose silty sands and had the appearance of possible fill materials. These soils are considered to be generally suitable to be left in place below slab areas. We recommend the bottom of the footing trenches be evaluated by qualified geotechnical personnel in order to better determine the suitability of the bearing soils. If overly loose and wet soils or debris-laden fill are present, some below footing corrections may be warranted. At this time potential corrections are expected to be on the order of 1 foot or less. With the understood foundation loads and implementation of the earthwork recommendations, we are of the opinion that the foundations may be designed to exert a bearing pressure of 3,000 psf. Total settlement is expected to be about 1 inch and differential settlement is expected to be on the order of ½ inch or less between footings that are similarly loaded. Proposed Gedney Property Development June 28, 2007 Project: #R2007.163 Page - 2 ____________________________________________________________________________________________ La Crosse, WI St. Cloud, MN Mankato, MN Rochester, MN Remarks We appreciate the chance to provide our professional services to you. The attached report provides more details of our recommendations for the proposed project. If you have any questions about our report, please call us at (507) 281-0968. Sincerely, Chosen Valley Testing, Inc. Jay Nopola, PE Geological Engineer Colby T. Verdegan, PE Geotechnical and Materials Engineer __________________________________________________________________________________________________________ La Crosse, WI St. Cloud, MN Mankato, MN Rochester, MN Design Phase Geotechnical Evaluation Proposed Development of Gedney Property 2100 Stoughton Avenue Chaska, Minnesota CVT Project Number: R2007.163 Date: June 28, 2007 A. Introduction The intent of this report is to present our results to the client in the same logical sequence that led us to arrive at the opinions and recommendations expressed. Since our services must often be completed before the design, assumptions are sometimes needed to prepare a proper evaluation and to analyze the data. A complete and thorough review of this entire document, including the assumptions and the appendices, should be undertaken immediately upon receipt. A.1. Purpose This report was prepared to assist planning for possible future buildings on the Gedney property in Chaska, Minnesota. Our services were authorized by Mr. Joel Buttenhoff of 5th Street Ventures. A.2. Scope To obtain data for analysis, we were authorized to perform a total of 15 penetration test borings in the proposed building area. Four of these borings were drilled in the area just west of the Gedney Plant around the existing rows of tanks. The remaining borings were drilled in the field to the north/northwest of the plant. The borings were drilled to depths of about 20 feet. A.3. Boring Locations and Elevation The desired boring locations were selected by Chosen Valley Testing based on information provided by 5th Street Ventures. The approximate locations of the borings are shown on the Boring Location Sketch in the Appendix. Ground surface elevations were estimated using a level. The top nut of the fire hydrant located at the intersection of Stoughton Ave. and Audubon Road was used as a benchmark. This benchmark was assigned an elevation of 100.0 feet. A.4. Geologic Background A geotechnical report is based on subsurface data collected for the specific structure or problem. Available geologic data from the region can help interpretation of the data and is briefly summarized in this section. Geologic maps indicate that the natural soils at the site are glacial outwash deposits of sand and gravel. Bedrock is expected to be about 150 to 200 feet below the surface. The uppermost bedrock is expected to be from the St. Lawrence or Franconia Formation. B. Subsurface Data Methods: All of the borings were performed using penetration test procedures (Method of Test D1586 of the American Society for Testing and Materials). This procedure allows for the extraction of intact soil specimen from deep in the ground. With this method, a hollow-stem auger is drilled to the desired sampling depth. A 2-inch OD sampling tube is then screwed onto the end of a sampling rod, inserted through the hole in the auger's tip, and then driven into the soil with a 140-pound hammer dropped repeatedly from a height of 30 inches above the sampling rod. The sampler is driven 18-inches into the soil, unless the material is too hard. The samples are generally taken at 2½- to 5- foot intervals. The core of soil obtained is classified and logged by the driller and a representative portion is then sealed in a jar and delivered to the soils engineer for review. B.1. Strata Proposed Gedney Property Development June 28, 2007 Project: #R2007.163 Page - 2 __________________________________________________________________________________________________________ La Crosse, WI St. Cloud, MN Mankato, MN Rochester, MN The southwestern borings (B-1 to B-4) encountered about 1½ feet of aggregate base at the surface. The other borings encountered about 1½ feet of topsoil. Outwash sands were the dominant soils encountered below the topsoil. Fine sands were often encountered below the topsoil or aggregate, and extended to depths of about 4 to 12 feet. Silty sands were met below the surficial materials in Borings B-4 to B-7 and B-12 to depths of about 4 to 7 feet. Some of these soils had the appearance of possible fill. At depth all of the borings were dominated by medium to coarse sand, often containing gravel, which was met until the termination depths at about 21 feet. For the reader’s convenience, a generalized cross section of the borings is provided below. For more detailed information, the reader is referred to the boring logs in the Appendix. 70 75 80 85 90 95 100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Boring NumberApproximate ElevationAggregate Base Topsoil Silty Sand Fine Sand Sand & Gravel Below Boring B.2. Penetration Test Results The number of blows needed for the hammer to advance the penetration test sampler is an indicator of soil characteristics. The number of blows to advance the sampler 1 foot is called the penetration resistance or “N”-value. The results tend to be more meaningful for natural mineral soils, than for fill soils. In fill soils, compaction tests are more meaningful. The upper, fine sand returned values of 2 to 18 Blows per Foot (BPF), indicating they ranged from very loose to medium dense, but were most often very loose to loose. Resistance values in the silty sand were 4 to 17 Blows per Foot (BPF), indicating they ranged from very loose to medium dense, but were also typically very loose to loose. The sands and gravels at depth had values ranging from 8 to 57, indicating they were loose to Proposed Gedney Property Development June 28, 2007 Project: #R2007.163 Page - 3 __________________________________________________________________________________________________________ La Crosse, WI St. Cloud, MN Mankato, MN Rochester, MN very dense, but were most often medium dense. B.3. Groundwater Data During the drilling operation, the drillers may note the presence of moisture on the sampling instrument, in the cuttings, or within the boreholes. These observations are recorded on the boring logs. The water level may vary with weather; time of year and other factors and the presence or absence of water during the drilling is subject to interpretation and is not always conclusive. Free water was not observed in any of the boreholes and the majority of the samples were only moist. Based on the findings, it appears that the static groundwater level in the areas of exploration is below the depths explored. The upper silty sands were often wet, likely due to water perching in these soils. C. Project Design Data Each structure has a different loading configuration and intensity, different grades, and different structural and performance tolerances. Therefore, the geotechnical exploration will be construed differently from one structure to another. If the initial structure should change design, we should be engaged to review these conditions with respect to the prevailing soil conditions. Without the opportunity to review any such changes, the recommendations may no longer be valid or appropriate. Specific design information for the buildings is still preliminary at this time. Our recommendations are therefore preliminary and would ideally be reviewed once specific design information becomes available. The proposed buildings will likely be commercial, single story, slab-on-grade structures, likely of masonry and steel- frame construction. For purposes of analysis, we have assumed that strip-footing loads for the buildings would be on the order of 4,000 pounds per foot of wall and column loads may be on the order of 100,000 pounds. The site is fairly level and we anticipate only minor cutting/filling on the order of 0 to 3 feet. D. Analysis We recommend stripping the topsoil and aggregate base from below the building and oversize areas. These soils were about 1½ feet deep. Most of the borings to the north and northeast encountered loose sands below the topsoil. The far southern borings encountered similar sands. These sands were relatively clean and would respond well to surface compaction. We recommend surface compacting the sands present at footing grade. This can likely be accomplished with a small turtle type compactor. The uppermost soils in the northwest borings (B-4 to B-7) and those near Highway 212 (B-12) were very loose to loose silty sands. These silty sands were typically wet and some of had the appearance of possible fill materials. These soils were granular and considered to be generally suitable to be left in place below slab areas. We recommend the bottom of the footing trenches are evaluated by qualified geotechnical personnel in order to better determine the suitability of the bearing soils. If overly loose and wet soils or debris-laden fill are present, some below footing corrections may be warranted. At this time potential corrections are expected to be on the order of 1 foot or less. Frost-depth footings are expected to bear primarily in the natural sands. With the understood foundation loads and implementation of the earthwork recommendations, we are of the opinion that the foundations may be designed to exert a bearing pressure of 3,000 psf. Total settlement is expected to be about 1 inch and differential settlement is expected to be on the order of ½ inch or less between footings that are similarly Proposed Gedney Property Development June 28, 2007 Project: #R2007.163 Page - 4 __________________________________________________________________________________________________________ La Crosse, WI St. Cloud, MN Mankato, MN Rochester, MN loaded. The remainder of this report provides more details of our recommendations for the proposed building. E. Building Recommendations E.1. Grading Recommendations E.1.a. Stripping/Excavations: We recommend that any topsoil or aggregate base be stripped from the proposed building and over-sized areas. These materials were about 1½ feet deep at the locations explored. E.1.b. Oversizing: Any corrective excavations should be oversized at least 1 foot beyond the building areas for each foot of fill needed below footing grade. This over-sizing can be reduced by up to 50% if rather precise staking is present during grading. E.1.c. Filling and Compaction: All fill below the building and in the oversized area should be compacted to a minimum of 95 percent of its maximum standard Proctor density. The on-site, natural sand materials should be suitable for general use as fill. If below footing corrections are needed, we recommend using clean sands or gravels that have less than 10% particles passing the number 200 sieve. We recommend placing at least 4 to 6 inches of cleaner sands having less than 5% particles passing a number 200 sieve at the top of the subgrade (just below slabs). All fill below building areas should be compacted to at least 95 percent of its standard Proctor density. Compaction tests are recommended to document that these compaction levels have been achieved. E.1.d. Surface Compaction: Many of the upper sands were very loose to loose. As a precaution, we recommend surface compacting the bearing soils in areas where clean sands are present at footing grade. This can likely be accomplished with a turtle-type compactor. E.1.e. Review of Bearing Soils: Silty sands, some of which had the appearance of possible fill, are expected directly west of the existing Gedney building. Because these soils were granular, they are expected to be suitable to be left in place below slab areas. We recommend that any silty sands present at footing grade are reviewed by qualified geotechnical personnel to better assess their suitability. If overly loose or wet soils are encountered, some below footing corrections may be warranted. Based on our findings, possible corrections are expected to be about 1 foot below footings or less. E.2. Building Design E.2.a. Foundation Depth: We recommend placing foundations for heated structures at least 42 inches below the exposed ground surface for frost protection. Interior footings in heated structures may be placed immediately below the slab. We recommend placing foundations for unheated structures at least 60 inches below the exposed ground surface. E.2.b. Bearing Capacity and Settlement: With the understood foundation loads and implementation of the earthwork recommendations, the bearing soils are estimated to have a bearing capacity of 3,000 psf. This capacity includes a safety factor of at least 3 against shear failure. Proposed Gedney Property Development June 28, 2007 Project: #R2007.163 Page - 5 __________________________________________________________________________________________________________ La Crosse, WI St. Cloud, MN Mankato, MN Rochester, MN With the recommended soil corrections and anticipated foundation loads, total settlement is expected to be about 1 inch. Differential settlement is expected to be on the order of ½ inch or less between footings that are similarly loaded. E.2.c. Vapor Barrier: A vapor barrier is recommended below slabs which will receive floor coverings. Some contractors prefer to place this below a sand layer, to reduce the potential for curling. E.2.d. Slab Design: The completed subgrade is expected to consist primarily of compacted sand soils. We recommend using a modulus of subgrade reaction of up to 200 pounds per cubic inch for these materials. F. Paved Areas F.1. Stripping and Grading We recommend removing the topsoil and existing paving materials from below paved areas. The soils after stripping and grading are expected to consist of materials ranging from clean sands to silty sands. To provide more uniform support to the pavement, the subgrade soils should be graded as needed to even out any localized discontinuities in the subgrade soils and provide a gradational transition between soil types. This will also help to limit differential frost heave. We recommend thoroughly mixing and scarifying the subgrade and then compacting these soils to at least 95% of the soil’s maximum standard Proctor density. Fill in the upper 3 feet of roads should be compacted to at least 100% of the soils maximum standard Proctor density. F.2. Pavement Design The R-values for the subgrade will vary depending on the materials present. The silty sands are expected to have R-values on the order of 30 to 50, and up to 70 for clean sands. In the absence of specific traffic loading data, we suggest a subgrade consisting of at least 3 inches of bituminous over 6 inches of aggregate base in auto traffic areas, and 3 ½ inches of bituminous and 8 inches of aggregate in truck traffic areas. G. General Grading Recommendations G.1. Excavation The stripping operations can likely be accomplished with a variety of equipment. Rubber tired equipment often has difficulty traversing in dry sands. G.2. Dewatering We expect that any water that is able to collect in excavation areas can be removed with a sump pump. G.3. Compaction All fill should be placed in lifts adjusted to the compactor being used and the material being compacted. We recommend limiting lifts to no more than 2 feet for imported clean sands or gravels and no more than 1 foot for silt or clay materials – assuming large, self-propelled or tow-behind compactors are used. If the earthwork occurs during freezing temperatures, good winter construction practices should be used. No frozen fill should be used nor should structural filling take place on frozen ground. G.4. Construction Testing and Documentation Ideally, the bottom of all excavations should be evaluated and documented by qualified geotechnical Proposed Gedney Property Development June 28, 2007 Project: #R2007.163 Page - 6 __________________________________________________________________________________________________________ La Crosse, WI St. Cloud, MN Mankato, MN Rochester, MN personnel after the unsuitable soils are removed from the building and oversize area and before filling. Fill placed below building areas should be evaluated for conformance to the project gradation recommendations and should be tested for compaction. If the filling proceeds during periods of freezing weather, full-time testing should be considered to help confirm that imported fill is thawed prior to and during compaction and that all snow has been removed before placement of the fill. Although our firm offers testing services relating to civil and structural components of the building (such as concrete testing, reinforcement observations, etc.) specification of such services is beyond our work scope and the designer should be consulted as to such requirements. H. Level of Care The services provided for this project have been conducted in a manner consistent with that level of care and skill ordinarily exercised by members of the profession currently practicing in this area under similar budget and time constraints. This is our professional responsibility. No other warranty, expressed or implied, is made. I. Certification I hereby certify that this report was prepared by me or under my direct supervision and that I am a duly registered engineer under the laws of the State of Minnesota. Colby T. Verdegan, PE Registration number 18983 Date: June 28, 2007 feetmeters500100 92.1 21.0 18.0 1.5 6.0 96.6 80.1 77.1 SP SP SP 98.1 Tests or Notes 12 16 10 10 11 18 6 0.0 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, fine to medium grained, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, fine grained, brown, moist, loose to medium dense. (Glacial Outwash) 18" AGGREGATE BASE Benchmark: Top nut of fire hydrant located at intersection of Stoughton Ave. and Audubon Road, assigned 100.0 feet. L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL B-01 page 1 of 1 PROJECT: See attached sketch. DATE: 6/14/07 SCALE: R2007.163LOB R2007-163.GPJ 10/24/12R2007.163 Proposed Development of Gedney Property 2100 Stoughton Ave. Chaska, Minnesota BORING:B-01 LOCATION:(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)1" = 3' 91.3 21.0 1.5 18.0 Tests or Notes 95.8 79.3 76.3 SP SP 97.3 6.0 16 24 17 13 22 12 12 0.0 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, fine to medium grained, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, fine grained, brown, moist, medium dense. (Glacial Outwash) 18" AGGREGATE BASE SP L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL LOB R2007-163.GPJ 10/24/12PROJECT: See attached sketch. DATE: 6/14/07 SCALE: 1" = 3' B-02 page 1 of 1 R2007.163 Proposed Development of Gedney Property 2100 Stoughton Ave. Chaska, Minnesota BORING:B-02 LOCATION:(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 93.2 21.0 1.5 18.0 Tests or Notes 96.7 80.2 77.2 SP SP 98.2 5.0 23 20 17 17 16 15 18 0.0 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, fine to medium grained, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, fine grained, brown, moist, medium dense. (Glacial Outwash) AGGREGATE BASE SP L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL LOB R2007-163.GPJ 10/24/12PROJECT: See attached sketch. DATE: 6/14/07 SCALE: 1" = 3' B-03 page 1 of 1 R2007.163 Proposed Development of Gedney Property 2100 Stoughton Ave. Chaska, Minnesota BORING:B-03 LOCATION:(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 94.4 21.0 1.5 7.0 Tests or Notes 96.9 91.4 77.4 SM SP 0.0 4.0 57 10 11 12 30 11 4 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, loose to very dense. (Glacial Outwash) SILTY SAND, fine to medium grained, brown, wet, medium dense. (Glacial Outwash) CLAYEY SAND TO SILTY SAND, fine grained, wet, dark brown to black, very loose. (Glacial Outwash/Possible Fill) AGGREGATE BASE 98.4 L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL LOB R2007-163.GPJ 10/24/12PROJECT: See attached sketch. DATE: 6/14/07 SCALE: 1" = 3' B-04 page 1 of 1 R2007.163 Proposed Development of Gedney Property 2100 Stoughton Ave. Chaska, Minnesota BORING:B-04 LOCATION:(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 R2007.163 17 B-05BORING: Chaska, Minnesota SM 2100 Stoughton Ave. Tests or Notes 19 LOB R2007-163.GPJ 10/24/12B-05 page 1 of 1R2007.163 1" = 3'SCALE:6/14/07 Proposed Development of Gedney Property Slightly Organic SILTY SAND, trace roots, fine grained, moist, dark brown to black. (Topsoil)1.5 4.0 21.0(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)22 LOCATION: 21 SILTY SAND, fine to medium grained, dark brown, trace gravel, wet, loose. (Glacial Outwash/Possible Fill) POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, medium dense. (Glacial Outwash) End of boring. Boring dry upon completion. Boring backfilled upon completion. 7 20 21 See attached sketch. L O G O F B O R I N G DATE: CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL PROJECT: 0.097.3 SP SM 95.8 93.3 76.3 21.0 1.5 4.0 Tests or Notes 76.3 Slightly Organic SILTY SAND, trace roots, fine grained, moist, dark brown to black. (Topsoil) SM SM SP 97.3 0.0 95.8 93.3 24 41 21 13 25 17 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, medium dense to dense. (Glacial Outwash) SILTY SAND, fine to medium grained, trace gravel, brown to light brown, wet, medium dense. (Glacial Outwash) 16 L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL LOB R2007-163.GPJ 10/24/12PROJECT: See attached sketch. DATE: 6/14/07 SCALE: 1" = 3' B-06 page 1 of 1 LOCATION: R2007.163(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 B-06BORING: Chaska, Minnesota 2100 Stoughton Ave. Proposed Development of Gedney Property 21.0 1.5 6.0 Tests or Notes 76.5 Slightly Organic SILTY SAND, trace roots, fine grained, moist, dark brown to light black. (Topsoil) SM SM SP 97.5 0.0 96.0 91.5 16 16 13 17 20 4 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, medium dense. (Glacial Outwash) SILTY SAND, fine to medium grained, brown, wet, very loose to loose. (Glacial Outwash) 7 L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL LOB R2007-163.GPJ 10/24/12PROJECT: See attached sketch. DATE: 6/14/07 SCALE: 1" = 3' B-07 page 1 of 1 LOCATION: R2007.163(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 B-07BORING: Chaska, Minnesota 2100 Stoughton Ave. Proposed Development of Gedney Property SM 1.596.0 Tests or Notes SP 97.5 0.0 20 21.0 SLIGHTLY ORGANIC SILTY SAND, trace roots, fine grained, moist, dark brown to black. (Topsoil) POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, loose to dense. (Glacial Outwash) End of boring. Boring dry upon completion. Boring backfilled upon completion. 9 22 76.5 26 34 15 10 Symbol D2487 ASTM DepthElev. CHOSEN VALLEY TESTING Description of Materials L O G O F B O R I N G R2007.163PROJECT: See attached sketch. DATE: 6/14/07 SCALE: 1" = 3' R2007.163LOB R2007-163.GPJ 10/24/12Proposed Development of Gedney Property (SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)Chaska, Minnesota BORING:B-08 WL LOCATION: BPF 2100 Stoughton Ave. B-08 page 1 of 1 (ASTM D2488) 21.0 1.5 9.0 Tests or Notes 74.6 Slightly Organic SILTY SAND, trace roots, fine grained, moist, dark brown to black. (Topsoil) SM SP SP 95.6 0.0 94.1 86.6 18 20 8 9 8 5 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, loose to medium dense. (Glacial Outwash) POORLY GRADED SAND, fine grained, brown, moist, loose. (Glacial Outwash) 6 L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL LOB R2007-163.GPJ 10/24/12PROJECT: See attached sketch. DATE: 6/15/07 SCALE: 1" = 3' B-09 page 1 of 1 LOCATION: R2007.163(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 B-09BORING: Chaska, Minnesota 2100 Stoughton Ave. Proposed Development of Gedney Property 21.0 1.5 7.0 Tests or Notes 73.6 Slightly Organic SILTY SAND, trace roots, fine grained, moist, dark brown to black. (Topsoil) SM SP SP 94.6 0.0 93.1 87.6 30 19 17 13 12 8 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, medium grained, with gravel, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, fine grained, brown, moist, loose. (Glacial Outwash) 8 L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL LOB R2007-163.GPJ 10/24/12PROJECT: See attached sketch. DATE: 6/15/07 SCALE: 1" = 3' B-10 page 1 of 1 LOCATION: R2007.163(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 B-10BORING: Chaska, Minnesota 2100 Stoughton Ave. Proposed Development of Gedney Property 90.5 21.0 12.0 1.5 7.0 96.0 85.5 76.5 SM SP SP 97.5 Tests or Notes 19 24 21 23 18 6 5 0.0 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, fine to medium grained, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, medium to coarse grained, with gravel, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, fine to medium grained, brown, moist, loose. (Glacial Outwash) Slightly Organic SILTY SAND, trace roots, fine grained, moist, dark brown to black. (Topsoil) SP L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL B-11 page 1 of 1 PROJECT: See attached sketch. DATE: 6/15/07 SCALE: R2007.163LOB R2007-163.GPJ 10/24/12R2007.163 Proposed Development of Gedney Property 2100 Stoughton Ave. Chaska, Minnesota BORING:B-11 LOCATION:(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)1" = 3' 21.0 1.5 6.0 Tests or Notes 76.7 Slightly Organic SILTY SAND, trace roots, fine grained, moist, dark brown to black. (Topsoil) SM SM SP 97.7 0.0 96.2 91.7 49 26 20 18 13 4 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, medium to coarse grained, with gravel, brown, moist, medium dense to dense. (Glacial Outwash) SILTY SAND, fine to medium grained, brown to dark brown, moist to wet, very loose to loose. (Glacial Outwash) 5 L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL LOB R2007-163.GPJ 10/24/12PROJECT: See attached sketch. DATE: 6/15/07 SCALE: 1" = 3' B-12 page 1 of 1 LOCATION: R2007.163(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 B-12BORING: Chaska, Minnesota 2100 Stoughton Ave. Proposed Development of Gedney Property 21.0 1.5 12.0 Tests or Notes 74.7 Slightly Organic SILTY SAND, trace roots, fine grained, moist, dark brown to black. (Topsoil) SM SP SP 95.7 0.0 94.2 83.7 31 23 16 7 8 2 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, medium to coarse grained, with gravel, brown, moist, medium dense to dense. (Glacial Outwash) POORLY GRADED SAND, fine grained, brown, moist, very loose to loose. (Glacial Outwash) 4 L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL LOB R2007-163.GPJ 10/24/12PROJECT: See attached sketch. DATE: 6/15/07 SCALE: 1" = 3' B-13 page 1 of 1 LOCATION: R2007.163(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 B-13BORING: Chaska, Minnesota 2100 Stoughton Ave. Proposed Development of Gedney Property 21.0 1.5 11.0 Tests or Notes 75.5 Slighty Organic SILTY SAND, trace roots, fine grained, moist, dark brown to black. (Topsoil) SM SP SP 96.5 0.0 95.0 85.5 17 16 16 6 7 4 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, fine grained, brown, moist, very loose to loose. (Glacial Outwash) 5 L O G O F B O R I N G CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL LOB R2007-163.GPJ 10/24/12PROJECT: See attached sketch. DATE: 6/15/07 SCALE: 1" = 3' B-14 page 1 of 1 LOCATION: R2007.163(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 B-14BORING: Chaska, Minnesota 2100 Stoughton Ave. Proposed Development of Gedney Property CHOSEN VALLEY TESTING Elev. Depth ASTM D2487 Symbol Description of Materials (ASTM D2488) BPF WL Tests or Notes 1.5 11.0 PROJECT: 18 See attached sketch. 7 5 4 21.0 End of boring. Boring dry upon completion. Boring backfilled upon completion. POORLY GRADED SAND, medium to coarse grained, trace gravel, brown, moist, medium dense. (Glacial Outwash) POORLY GRADED SAND, fine grained, brown, moist, very loose to loose. (Glacial Outwash) SLIGHTLY ORGANIC SILTY SAND, trace roots, fine grained, moist, dark brown to black. (Topsoil)LOB R2007-163.GPJ 10/24/12L O G O F B O R I N G B-15BORING: Chaska, Minnesota 2100 Stoughton Ave.(SEE REPORT AND STANDARD PLATES FOR EVALUATION AND DESCRIPTIVE TERMINOLOGY.)R2007.163 B-15 page 1 of 1R2007.163 1" = 3'SCALE:6/15/07DATE: Proposed Development of Gedney Property 18 LOCATION: 94.8 75.3 85.3 SM 21 6 SP 0.096.3 SP Appendix B – Drainage Diagrams PUGPUGPUGPUGPUGPUGPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHXXXXXXXE 70227023DSDSFFE=759.46DSDSDSDSDSDSDSDSFFE=760.00SSTEEEESFOFOFOFOFOFOFOFOFO GASGASGASGASGASGASGASGASGASGASGASGASGASGASGAS POHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHSTOSTOSTOSTOSTO STOWATWATWATWATWAT WAT WAT WAT WAT WAT WATWATWATSANSANSANSANSANSANSANSANSANSANSANSANSANRE=755.72INV SW=752.07RE=755.7INV NE/NW=751.77RE=755.62INV NW=749.72INV SE/SW UNABLE TO MEASURERE=756.10NO INVERTSRE=756.37INV SW/NW=751.87RE=756.74INV SE=753.34RE=756.42INV N/SE=751.62INV E UNABLE TO MEASURERE=756.48INV W=752.58RE=757.20INV S=752.55RE=757.90INV NE=750.55RE=757.30INV N/W=750.90RIM=757.21INV=747.46RIM=757.93INV=748.58WATER TOWERTRANSMISSIONLINE TOWERTANKSELEVATEDWALKWAYBUILDINGBUILDINGELEVATEDWALKWAYTANKSBUILDING756756 757757757757 757757758758758758758758759759759759759757757757757758759757757757757758758759759759758 759756757758756757758759759759759758759757758756757758759758757RETAINING WALLELECTRICCABINETTRANSMISSION LINE EASEMENTPER DOC NO. A455245AUDUBON ROAD CHASKA BLVD. (COUNTY ROAD 61)STOUGHTON AVENUEAREA NOT FULLY SURVEYED125.00PARCEL PARCEL 2 PARCEL ESSSWSANSANSANRIM=758.96INV=749.77RIM=759.21INV=749.73RIM=755.61INV=751.60RE=753.61INV SE=753.32GUARD RAIL755210211EEEEEEEEEEPUGPUGPUGPUGPUGPUGPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHX X XXXXX 70227023DSDSFFE=759.46DSDSDSDSDSDSDSDSFFE=760.00SSTEEEESFOFOFOFOFOFOFO FO FO GASGASGASGASGASGASGASGASGASGASGASGASGAS GASGASPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHSTOSTOSTOSTOSTO STOWATWATWATWATWAT WAT WAT WAT WAT WAT WATWATWATSANSANSANSANSANSANSANSANSANSANSANSANSANRE=755.72INV SW=752.07RE=755.7RE=755.62INV NW=749.72INV SE/SW UNABLE TO MEASURERE=756.10NO INVERTSRE=756.37INV SW/NW=751.87RE=756.74INV SE=753.34RE=756.42INV N/SE=751.62INV E UNABLE TO MEASURERE=756.48INV W=752.58RE=757.20INV S=752.55RE=757.90INV NE=750.55RE=757.30INV N/W=750.90RIM=757.21INV=747.46RIM=757.93INV=748.58TRANSMISSIONLINE TOWERBUILDING756 756757757757 757757757758758758758758 758759 759759759 759757757757757758759757757757757758758759 7597597587 5 9 7 5 6 7 5 7 7 5 8 7 5 6 7 5 7 7 5 8 75 9 7 5 9 759 759758759757758756757758759758757 RETAINING WALLELECTRICCABINETTRANSMISSION LINE EASEMENTPER DOC NO. A455245AUDUBON ROAD CHASKA BLVD. (COUNTY ROAD 61)STOUGHTON AVENUEAREA NOT FULLY SURVEYED125.00 P A R C E L PARCEL 2 PARCEL ESSSWSANSANSANRIM=758.96INV=749.77RIM=759.21INV=749.73RIM=755.61INV=751.60RE=753.61INV SE=753.32GUARD RAIL755210211CIVIL METHODS, INC.PO Box 28038St. Paul, MN 55128o:763.210.5713 | www.civilmethods.comRIVER VALLEY BUSINESS CENTERCORNERSTONE INVESTORS, LLCCHASKA, MNDRAINAGE DIAGRAMEXISTING CONDITIONPROPOSED CONDITIONLEGEND: Feet060120CHANHASSEN, MN Appendix C –HydroCAD Report E1 Existing to Southwest E2 Existing to Northeast E3 Existing to Southeast 1R Entire Project Site Discharge E2i Existing field depression Routing Diagram for 23089_River Valley Center_EX Prepared by Civil Methods, Inc., Printed 1/8/2026 HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link MSE 24-hr 3 2-Year Rainfall=2.84"23089_River Valley Center_EX Printed 1/8/2026Prepared by Civil Methods, Inc. Page 2HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment E1: Existing to Southwest Runoff =1.65 cfs @ 12.45 hrs, Volume=0.176 af, Depth= 0.58" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.84" Area (sf) CN Description *35,248 98 122,378 39 >75% Grass cover, Good, HSG A 157,626 52 Weighted Average 122,378 39 77.64% Pervious Area 35,248 98 22.36% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.8 100 0.0100 0.12 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 18.7 450 0.0033 0.40 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 32.5 550 Total Summary for Subcatchment E2: Existing to Northeast Runoff =0.35 cfs @ 12.40 hrs, Volume=0.048 af, Depth= 0.25" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.84" Area (sf) CN Description 100,564 59 Small grain, C&T, Good, HSG A 100,564 59 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.3 100 0.0100 0.11 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 2.80" 2.5 150 0.0200 0.99 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 17.8 250 Total Summary for Subcatchment E3: Existing to Southeast Runoff =3.14 cfs @ 12.13 hrs, Volume=0.160 af, Depth= 2.15" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.84" MSE 24-hr 3 2-Year Rainfall=2.84"23089_River Valley Center_EX Printed 1/8/2026Prepared by Civil Methods, Inc. Page 3HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Area (sf) CN Description *28,160 98 10,739 77 Newly graded area, HSG A 38,899 92 Weighted Average 10,739 77 27.61% Pervious Area 28,160 98 72.39% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.0 Direct Entry, Summary for Reach 1R: Entire Project Site Discharge Inflow Area =6.820 ac, 21.34% Impervious, Inflow Depth = 0.59" for 2-Year event Inflow =3.87 cfs @ 12.13 hrs, Volume=0.336 af Outflow =3.87 cfs @ 12.13 hrs, Volume=0.336 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Summary for Pond E2i: Existing field depression Inflow Area =2.309 ac, 0.00% Impervious, Inflow Depth = 0.25" for 2-Year event Inflow =0.35 cfs @ 12.40 hrs, Volume=0.048 af Outflow =0.08 cfs @ 13.75 hrs, Volume=0.048 af, Atten= 77%, Lag= 81.3 min Discarded =0.08 cfs @ 13.75 hrs, Volume=0.048 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 756.95' @ 13.75 hrs Surf.Area= 2,850 sf Storage= 690 cf Plug-Flow detention time= 105.1 min calculated for 0.048 af (100% of inflow) Center-of-Mass det. time= 105.1 min ( 1,009.9 - 904.8 ) Volume Invert Avail.Storage Storage Description #1 756.50'54,398 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 756.50 200 0 0 757.00 3,130 833 833 758.00 27,000 15,065 15,898 759.00 50,000 38,500 54,398 Device Routing Invert Outlet Devices #1 Discarded 756.50'1.200 in/hr Exfiltration over Surface area #2 Primary 758.00'Runout Elev, Cv= 2.62 (C= 3.28) Head (feet) 0.00 1.00 Width (feet) 20.00 200.00 MSE 24-hr 3 2-Year Rainfall=2.84"23089_River Valley Center_EX Printed 1/8/2026Prepared by Civil Methods, Inc. Page 4HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Discarded OutFlow Max=0.08 cfs @ 13.75 hrs HW=756.95' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.08 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=756.50' TW=0.00' (Dynamic Tailwater) 2=Runout Elev ( Controls 0.00 cfs) MSE 24-hr 3 10-Year Rainfall=4.20"23089_River Valley Center_EX Printed 1/8/2026Prepared by Civil Methods, Inc. Page 5HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment E1: Existing to Southwest Runoff =2.46 cfs @ 12.45 hrs, Volume=0.283 af, Depth= 0.94" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.20" Area (sf) CN Description *35,248 98 122,378 39 >75% Grass cover, Good, HSG A 157,626 52 Weighted Average 122,378 39 77.64% Pervious Area 35,248 98 22.36% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.8 100 0.0100 0.12 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 18.7 450 0.0033 0.40 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 32.5 550 Total Summary for Subcatchment E2: Existing to Northeast Runoff =1.83 cfs @ 12.31 hrs, Volume=0.156 af, Depth= 0.81" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.20" Area (sf) CN Description 100,564 59 Small grain, C&T, Good, HSG A 100,564 59 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.3 100 0.0100 0.11 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 2.80" 2.5 150 0.0200 0.99 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 17.8 250 Total Summary for Subcatchment E3: Existing to Southeast Runoff =4.94 cfs @ 12.13 hrs, Volume=0.254 af, Depth= 3.41" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.20" MSE 24-hr 3 10-Year Rainfall=4.20"23089_River Valley Center_EX Printed 1/8/2026Prepared by Civil Methods, Inc. Page 6HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Area (sf) CN Description *28,160 98 10,739 77 Newly graded area, HSG A 38,899 92 Weighted Average 10,739 77 27.61% Pervious Area 28,160 98 72.39% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.0 Direct Entry, Summary for Reach 1R: Entire Project Site Discharge Inflow Area =6.820 ac, 21.34% Impervious, Inflow Depth = 0.95" for 10-Year event Inflow =6.04 cfs @ 12.13 hrs, Volume=0.537 af Outflow =6.04 cfs @ 12.13 hrs, Volume=0.537 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Summary for Pond E2i: Existing field depression Inflow Area =2.309 ac, 0.00% Impervious, Inflow Depth = 0.81" for 10-Year event Inflow =1.83 cfs @ 12.31 hrs, Volume=0.156 af Outflow =0.29 cfs @ 13.53 hrs, Volume=0.156 af, Atten= 84%, Lag= 73.4 min Discarded =0.29 cfs @ 13.53 hrs, Volume=0.156 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 757.30' @ 13.53 hrs Surf.Area= 10,328 sf Storage= 2,862 cf Plug-Flow detention time= 144.7 min calculated for 0.156 af (100% of inflow) Center-of-Mass det. time= 144.7 min ( 1,008.0 - 863.3 ) Volume Invert Avail.Storage Storage Description #1 756.50'54,398 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 756.50 200 0 0 757.00 3,130 833 833 758.00 27,000 15,065 15,898 759.00 50,000 38,500 54,398 Device Routing Invert Outlet Devices #1 Discarded 756.50'1.200 in/hr Exfiltration over Surface area #2 Primary 758.00'Runout Elev, Cv= 2.62 (C= 3.28) Head (feet) 0.00 1.00 Width (feet) 20.00 200.00 MSE 24-hr 3 10-Year Rainfall=4.20"23089_River Valley Center_EX Printed 1/8/2026Prepared by Civil Methods, Inc. Page 7HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Discarded OutFlow Max=0.29 cfs @ 13.53 hrs HW=757.30' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.29 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=756.50' TW=0.00' (Dynamic Tailwater) 2=Runout Elev ( Controls 0.00 cfs) MSE 24-hr 3 100-Year Rainfall=7.18"23089_River Valley Center_EX Printed 1/8/2026Prepared by Civil Methods, Inc. Page 8HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment E1: Existing to Southwest Runoff =5.34 cfs @ 12.46 hrs, Volume=0.663 af, Depth= 2.20" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.18" Area (sf) CN Description *35,248 98 122,378 39 >75% Grass cover, Good, HSG A 157,626 52 Weighted Average 122,378 39 77.64% Pervious Area 35,248 98 22.36% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 13.8 100 0.0100 0.12 Sheet Flow, Grass: Short n= 0.150 P2= 2.80" 18.7 450 0.0033 0.40 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 32.5 550 Total Summary for Subcatchment E2: Existing to Northeast Runoff =7.06 cfs @ 12.28 hrs, Volume=0.506 af, Depth= 2.63" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.18" Area (sf) CN Description 100,564 59 Small grain, C&T, Good, HSG A 100,564 59 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 15.3 100 0.0100 0.11 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 2.80" 2.5 150 0.0200 0.99 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 17.8 250 Total Summary for Subcatchment E3: Existing to Southeast Runoff =8.97 cfs @ 12.13 hrs, Volume=0.467 af, Depth= 6.27" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.18" MSE 24-hr 3 100-Year Rainfall=7.18"23089_River Valley Center_EX Printed 1/8/2026Prepared by Civil Methods, Inc. Page 9HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Area (sf) CN Description *28,160 98 10,739 77 Newly graded area, HSG A 38,899 92 Weighted Average 10,739 77 27.61% Pervious Area 28,160 98 72.39% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.0 Direct Entry, Summary for Reach 1R: Entire Project Site Discharge Inflow Area =6.820 ac, 21.34% Impervious, Inflow Depth = 1.99" for 100-Year event Inflow =10.89 cfs @ 12.13 hrs, Volume=1.130 af Outflow =10.89 cfs @ 12.13 hrs, Volume=1.130 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Summary for Pond E2i: Existing field depression Inflow Area =2.309 ac, 0.00% Impervious, Inflow Depth = 2.63" for 100-Year event Inflow =7.06 cfs @ 12.28 hrs, Volume=0.506 af Outflow =0.65 cfs @ 13.66 hrs, Volume=0.506 af, Atten= 91%, Lag= 82.6 min Discarded =0.65 cfs @ 13.66 hrs, Volume=0.506 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 757.85' @ 13.66 hrs Surf.Area= 23,433 sf Storage= 12,130 cf Plug-Flow detention time= 240.4 min calculated for 0.506 af (100% of inflow) Center-of-Mass det. time= 240.4 min ( 1,074.1 - 833.7 ) Volume Invert Avail.Storage Storage Description #1 756.50'54,398 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 756.50 200 0 0 757.00 3,130 833 833 758.00 27,000 15,065 15,898 759.00 50,000 38,500 54,398 Device Routing Invert Outlet Devices #1 Discarded 756.50'1.200 in/hr Exfiltration over Surface area #2 Primary 758.00'Runout Elev, Cv= 2.62 (C= 3.28) Head (feet) 0.00 1.00 Width (feet) 20.00 200.00 MSE 24-hr 3 100-Year Rainfall=7.18"23089_River Valley Center_EX Printed 1/8/2026Prepared by Civil Methods, Inc. Page 10HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Discarded OutFlow Max=0.65 cfs @ 13.66 hrs HW=757.85' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.65 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=756.50' TW=0.00' (Dynamic Tailwater) 2=Runout Elev ( Controls 0.00 cfs) P1 Proposed P2 Proposed to NE P3 Proposed to Southeast 1R Entire Project Site Discharge 1in Infiltration Basin 1 2in Infiltration Basin 2 Routing Diagram for 23089_River Valley Center_PR Prepared by Civil Methods, Inc., Printed 1/8/2026 HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link MSE 24-hr 3 2-Year Rainfall=2.84"23089_River Valley Center_PR Printed 1/8/2026Prepared by Civil Methods, Inc. Page 2HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P1: Proposed Runoff =7.29 cfs @ 12.27 hrs, Volume=0.578 af, Depth= 1.80" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.84" Area (sf) CN Description *107,073 98 Site Impervious *8,684 98 Street Impervious 52,185 39 >75% Grass cover, Good, HSG A 167,942 80 Weighted Average 52,185 39 31.07% Pervious Area 115,757 98 68.93% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.8 100 0.0150 0.59 Sheet Flow, n= 0.025 P2= 2.80" 1.6 200 0.0200 2.12 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 14.1 400 0.0010 0.47 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.5 700 Total Summary for Subcatchment P2: Proposed to NE Runoff =3.06 cfs @ 12.23 hrs, Volume=0.221 af, Depth= 1.19" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.84" Area (sf) CN Description *44,257 98 53,153 39 >75% Grass cover, Good, HSG A 97,410 66 Weighted Average 53,153 39 54.57% Pervious Area 44,257 98 45.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.8 100 0.0150 0.59 Sheet Flow, n= 0.025 P2= 2.80" 1.2 150 0.0200 2.12 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 11.3 150 0.0010 0.22 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 15.3 400 Total MSE 24-hr 3 2-Year Rainfall=2.84"23089_River Valley Center_PR Printed 1/8/2026Prepared by Civil Methods, Inc. Page 3HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P3: Proposed to Southeast Runoff =3.05 cfs @ 12.13 hrs, Volume=0.158 af, Depth= 2.61" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.84" Area (sf) CN Description *31,737 98 31,737 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.0 Direct Entry, Summary for Reach 1R: Entire Project Site Discharge Inflow Area =6.820 ac, 64.54% Impervious, Inflow Depth = 0.28" for 2-Year event Inflow =3.05 cfs @ 12.13 hrs, Volume=0.158 af Outflow =3.05 cfs @ 12.13 hrs, Volume=0.158 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Summary for Pond 1in: Infiltration Basin 1 Inflow Area =3.855 ac, 68.93% Impervious, Inflow Depth = 1.80" for 2-Year event Inflow =7.29 cfs @ 12.27 hrs, Volume=0.578 af Outflow =0.26 cfs @ 14.82 hrs, Volume=0.578 af, Atten= 96%, Lag= 152.9 min Discarded =0.26 cfs @ 14.82 hrs, Volume=0.578 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 753.62' @ 14.82 hrs Surf.Area= 11,195 sf Storage= 16,054 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 575.5 min ( 1,341.0 - 765.5 ) Volume Invert Avail.Storage Storage Description #1 752.00'78,047 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 752.00 8,657 0 0 754.00 11,795 20,452 20,452 756.00 16,200 27,995 48,447 757.00 43,000 29,600 78,047 Device Routing Invert Outlet Devices #1 Discarded 752.00'1.000 in/hr Exfiltration over Surface area #2 Primary 754.50'12.0" Round Culvert L= 40.0' Ke= 0.500 MSE 24-hr 3 2-Year Rainfall=2.84"23089_River Valley Center_PR Printed 1/8/2026Prepared by Civil Methods, Inc. Page 4HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Inlet / Outlet Invert= 754.50' / 754.30' S= 0.0050 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf Discarded OutFlow Max=0.26 cfs @ 14.82 hrs HW=753.62' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.26 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=752.00' TW=0.00' (Dynamic Tailwater) 2=Culvert ( Controls 0.00 cfs) Summary for Pond 2in: Infiltration Basin 2 Inflow Area =2.236 ac, 45.43% Impervious, Inflow Depth = 1.19" for 2-Year event Inflow =3.06 cfs @ 12.23 hrs, Volume=0.221 af Outflow =0.19 cfs @ 13.59 hrs, Volume=0.221 af, Atten= 94%, Lag= 82.0 min Discarded =0.19 cfs @ 13.59 hrs, Volume=0.221 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 754.72' @ 13.59 hrs Surf.Area= 8,015 sf Storage= 5,203 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 244.6 min ( 1,007.1 - 762.5 ) Volume Invert Avail.Storage Storage Description #1 754.00'31,170 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 754.00 6,340 0 0 755.00 8,650 7,495 7,495 756.00 11,500 10,075 17,570 757.00 15,700 13,600 31,170 Device Routing Invert Outlet Devices #1 Discarded 754.00'1.000 in/hr Exfiltration over Surface area #2 Primary 756.20'EOF, Cv= 2.62 (C= 3.28) Head (feet) 0.00 1.00 Width (feet) 8.00 12.00 Discarded OutFlow Max=0.19 cfs @ 13.59 hrs HW=754.72' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.19 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=754.00' TW=0.00' (Dynamic Tailwater) 2=EOF ( Controls 0.00 cfs) MSE 24-hr 3 10-Year Rainfall=4.20"23089_River Valley Center_PR Printed 1/8/2026Prepared by Civil Methods, Inc. Page 5HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P1: Proposed Runoff =10.88 cfs @ 12.27 hrs, Volume=0.885 af, Depth= 2.75" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.20" Area (sf) CN Description *107,073 98 Site Impervious *8,684 98 Street Impervious 52,185 39 >75% Grass cover, Good, HSG A 167,942 80 Weighted Average 52,185 39 31.07% Pervious Area 115,757 98 68.93% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.8 100 0.0150 0.59 Sheet Flow, n= 0.025 P2= 2.80" 1.6 200 0.0200 2.12 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 14.1 400 0.0010 0.47 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.5 700 Total Summary for Subcatchment P2: Proposed to NE Runoff =4.56 cfs @ 12.23 hrs, Volume=0.343 af, Depth= 1.84" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.20" Area (sf) CN Description *44,257 98 53,153 39 >75% Grass cover, Good, HSG A 97,410 66 Weighted Average 53,153 39 54.57% Pervious Area 44,257 98 45.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.8 100 0.0150 0.59 Sheet Flow, n= 0.025 P2= 2.80" 1.2 150 0.0200 2.12 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 11.3 150 0.0010 0.22 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 15.3 400 Total MSE 24-hr 3 10-Year Rainfall=4.20"23089_River Valley Center_PR Printed 1/8/2026Prepared by Civil Methods, Inc. Page 6HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P3: Proposed to Southeast Runoff =4.55 cfs @ 12.13 hrs, Volume=0.241 af, Depth= 3.96" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.20" Area (sf) CN Description *31,737 98 31,737 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.0 Direct Entry, Summary for Reach 1R: Entire Project Site Discharge Inflow Area =6.820 ac, 64.54% Impervious, Inflow Depth = 0.42" for 10-Year event Inflow =4.55 cfs @ 12.13 hrs, Volume=0.241 af Outflow =4.55 cfs @ 12.13 hrs, Volume=0.241 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Summary for Pond 1in: Infiltration Basin 1 Inflow Area =3.855 ac, 68.93% Impervious, Inflow Depth = 2.75" for 10-Year event Inflow =10.88 cfs @ 12.27 hrs, Volume=0.885 af Outflow =0.30 cfs @ 15.28 hrs, Volume=0.885 af, Atten= 97%, Lag= 180.8 min Discarded =0.30 cfs @ 15.28 hrs, Volume=0.885 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 754.47' @ 15.28 hrs Surf.Area= 12,839 sf Storage= 26,290 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 854.8 min ( 1,616.1 - 761.3 ) Volume Invert Avail.Storage Storage Description #1 752.00'78,047 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 752.00 8,657 0 0 754.00 11,795 20,452 20,452 756.00 16,200 27,995 48,447 757.00 43,000 29,600 78,047 Device Routing Invert Outlet Devices #1 Discarded 752.00'1.000 in/hr Exfiltration over Surface area #2 Primary 754.50'12.0" Round Culvert L= 40.0' Ke= 0.500 MSE 24-hr 3 10-Year Rainfall=4.20"23089_River Valley Center_PR Printed 1/8/2026Prepared by Civil Methods, Inc. Page 7HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Inlet / Outlet Invert= 754.50' / 754.30' S= 0.0050 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf Discarded OutFlow Max=0.30 cfs @ 15.28 hrs HW=754.47' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.30 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=752.00' TW=0.00' (Dynamic Tailwater) 2=Culvert ( Controls 0.00 cfs) Summary for Pond 2in: Infiltration Basin 2 Inflow Area =2.236 ac, 45.43% Impervious, Inflow Depth = 1.84" for 10-Year event Inflow =4.56 cfs @ 12.23 hrs, Volume=0.343 af Outflow =0.21 cfs @ 13.77 hrs, Volume=0.343 af, Atten= 95%, Lag= 92.5 min Discarded =0.21 cfs @ 13.77 hrs, Volume=0.343 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 755.13' @ 13.77 hrs Surf.Area= 9,011 sf Storage= 8,615 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 383.8 min ( 1,145.6 - 761.8 ) Volume Invert Avail.Storage Storage Description #1 754.00'31,170 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 754.00 6,340 0 0 755.00 8,650 7,495 7,495 756.00 11,500 10,075 17,570 757.00 15,700 13,600 31,170 Device Routing Invert Outlet Devices #1 Discarded 754.00'1.000 in/hr Exfiltration over Surface area #2 Primary 756.20'EOF, Cv= 2.62 (C= 3.28) Head (feet) 0.00 1.00 Width (feet) 8.00 12.00 Discarded OutFlow Max=0.21 cfs @ 13.77 hrs HW=755.13' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.21 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=754.00' TW=0.00' (Dynamic Tailwater) 2=EOF ( Controls 0.00 cfs) MSE 24-hr 3 100-Year Rainfall=7.18"23089_River Valley Center_PR Printed 1/8/2026Prepared by Civil Methods, Inc. Page 8HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P1: Proposed Runoff =19.30 cfs @ 12.27 hrs, Volume=1.620 af, Depth= 5.04" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.18" Area (sf) CN Description *107,073 98 Site Impervious *8,684 98 Street Impervious 52,185 39 >75% Grass cover, Good, HSG A 167,942 80 Weighted Average 52,185 39 31.07% Pervious Area 115,757 98 68.93% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.8 100 0.0150 0.59 Sheet Flow, n= 0.025 P2= 2.80" 1.6 200 0.0200 2.12 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 14.1 400 0.0010 0.47 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.5 700 Total Summary for Subcatchment P2: Proposed to NE Runoff =8.51 cfs @ 12.23 hrs, Volume=0.672 af, Depth= 3.61" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.18" Area (sf) CN Description *44,257 98 53,153 39 >75% Grass cover, Good, HSG A 97,410 66 Weighted Average 53,153 39 54.57% Pervious Area 44,257 98 45.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 2.8 100 0.0150 0.59 Sheet Flow, n= 0.025 P2= 2.80" 1.2 150 0.0200 2.12 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 11.3 150 0.0010 0.22 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 15.3 400 Total MSE 24-hr 3 100-Year Rainfall=7.18"23089_River Valley Center_PR Printed 1/8/2026Prepared by Civil Methods, Inc. Page 9HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P3: Proposed to Southeast Runoff =7.81 cfs @ 12.13 hrs, Volume=0.421 af, Depth= 6.94" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-96.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.18" Area (sf) CN Description *31,737 98 31,737 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft) (ft/sec)(cfs) 6.0 Direct Entry, Summary for Reach 1R: Entire Project Site Discharge Inflow Area =6.820 ac, 64.54% Impervious, Inflow Depth = 1.72" for 100-Year event Inflow =7.81 cfs @ 12.13 hrs, Volume=0.976 af Outflow =7.81 cfs @ 12.13 hrs, Volume=0.976 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Summary for Pond 1in: Infiltration Basin 1 Inflow Area =3.855 ac, 68.93% Impervious, Inflow Depth = 5.04" for 100-Year event Inflow =19.30 cfs @ 12.27 hrs, Volume=1.620 af Outflow =2.66 cfs @ 12.99 hrs, Volume=1.620 af, Atten= 86%, Lag= 43.2 min Discarded =0.35 cfs @ 12.99 hrs, Volume=1.066 af Primary =2.30 cfs @ 12.99 hrs, Volume=0.554 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 755.55' @ 12.99 hrs Surf.Area= 15,209 sf Storage= 41,378 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 648.4 min ( 1,407.8 - 759.4 ) Volume Invert Avail.Storage Storage Description #1 752.00'78,047 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 752.00 8,657 0 0 754.00 11,795 20,452 20,452 756.00 16,200 27,995 48,447 757.00 43,000 29,600 78,047 Device Routing Invert Outlet Devices #1 Discarded 752.00'1.000 in/hr Exfiltration over Surface area #2 Primary 754.50'12.0" Round Culvert L= 40.0' Ke= 0.500 MSE 24-hr 3 100-Year Rainfall=7.18"23089_River Valley Center_PR Printed 1/8/2026Prepared by Civil Methods, Inc. Page 10HydroCAD® 10.10-5a s/n 07283 © 2020 HydroCAD Software Solutions LLC Inlet / Outlet Invert= 754.50' / 754.30' S= 0.0050 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf Discarded OutFlow Max=0.35 cfs @ 12.99 hrs HW=755.55' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.35 cfs) Primary OutFlow Max=2.30 cfs @ 12.99 hrs HW=755.55' TW=0.00' (Dynamic Tailwater) 2=Culvert (Barrel Controls 2.30 cfs @ 3.47 fps) Summary for Pond 2in: Infiltration Basin 2 Inflow Area =2.236 ac, 45.43% Impervious, Inflow Depth = 3.61" for 100-Year event Inflow =8.51 cfs @ 12.23 hrs, Volume=0.672 af Outflow =0.28 cfs @ 15.20 hrs, Volume=0.672 af, Atten= 97%, Lag= 177.9 min Discarded =0.28 cfs @ 15.20 hrs, Volume=0.672 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 756.11' @ 15.20 hrs Surf.Area= 11,956 sf Storage= 18,843 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 697.8 min ( 1,464.5 - 766.7 ) Volume Invert Avail.Storage Storage Description #1 754.00'31,170 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 754.00 6,340 0 0 755.00 8,650 7,495 7,495 756.00 11,500 10,075 17,570 757.00 15,700 13,600 31,170 Device Routing Invert Outlet Devices #1 Discarded 754.00'1.000 in/hr Exfiltration over Surface area #2 Primary 756.20'EOF, Cv= 2.62 (C= 3.28) Head (feet) 0.00 1.00 Width (feet) 8.00 12.00 Discarded OutFlow Max=0.28 cfs @ 15.20 hrs HW=756.11' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.28 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=754.00' TW=0.00' (Dynamic Tailwater) 2=EOF ( Controls 0.00 cfs)