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2020-003_Moments of Chanhassen20200325_packet
Page | 1 18681 Lake Drive East Chanhassen, MN 55317 952-607-6512 www.rpbcwd.org protect. manage. restore. Riley Purgatory Bluff Creek Watershed District Permit Application Review Permit No: 2020-003 Considered at Board of Managers Meeting: April 1, 2020 Received complete: March 18, 2020 Applicant: TMSC of Chanhassen, LLC., Elizabeth Wright Consultant: Civil Site Group, Robbie Latta Project: The Moments of Chanhassen – The project proposes development of a 3.6-acre site in Chanhassen, MN. Proposed work includes construction of a 48-unit memory care residential facility with associated parking, grading, utilities, landscaping and stormwater management facilities. Stormwater management facilities including a filtration basin, infiltration basin, and a subsurface infiltration system will be constructed to provide volume control, water quality, and rate control. Location: 1620-1660 Arboretum Blvd Chanhassen, MN 55317 Reviewer: Louise Heffernan and Scott Sobiech P.E., Barr Engineering Proposed Board Action Manager ______________ moved and Manager ____________ seconded adoption of the following resolutions based on the permit report that follows and the presentation of the matter at the April 1, 2020 meeting of the managers: Resolved that the application for Permit 2020-003 is approved, subject to the conditions and stipulations set forth in the Recommendations section of the attached report; Resolved that on determination by the RPBCWD administrator that the conditions of approval have been affirmatively resolved, the RPBCWD president or administrator is authorized and directed to sign and deliver Permit 2020-003 to the applicant on behalf of RPBCWD. Upon vote, the resolutions were adopted, ______ [VOTE TALLY]. Page | 2 Applicable Rule Conformance Summary Rule Issue Conforms to RPBCWD Rules? Comments B Floodplain Management and Drainage Alterations See Comment See stipulation #1. C Erosion Control Plan See Comment See Rule Specific Permit Condition C1. D Wetland and Creek Buffers See Comment See Rule Specific Permit Condition D1-D2. G Waterbody Crossings See Comment See Rule Specific Permit Condition G1. J Stormwater Management Rate Yes Volume Yes See stipulation #3. Water Quality Yes Low Floor Elev. See Comment See Rule Specific Permit Condition J1. Maintenance See Comment See Rule Specific Permit Condition J2. Chloride Management See Comment See stipulation #6. Wetland Protection Yes L Permit Fee Deposit Yes $3,000 received January 22, 2020 M Financial Assurances See Comment The financial assurance is calculated at $451,601 Background The proposed project includes development of a 48-unit memory care residential facility with associated parking, grading, utilities, landscaping, an outfall to Riley Creek, and stormwater management facilities. The 3.6-acre site is currently undeveloped, and the open space is a combination of open grassland and wooded areas. The project proposes construction of three stormwater management facilities to provide stormwater quantity, volume and rate quality control. A filtration basin proposed at the eastern side of the property will provide water quality, rate control and abstraction for the eastern portion of the proposed parking Page | 3 areas and landscaping. The filtration basin has an elevated underdrain system to promote infiltration. A subsurface filtration system with elevated draintile is proposed beneath a portion of the parking area and will accept runoff from the western portion of the parking area and the building roof. The subsurface system will consist of a tire derived aggregate (TDA) field which will allow for infiltration beneath an outlet that discharges to the City of Chanhassen storm sewer system along West 78th Street. TDA is a relative new practice in Minnesota for stormwater management. A study from MnDOT (http://www.dot.state.mn.us/research/TS/2013/201320TS.pdf) states “Environmental concerns. In the 1990s, TDA’s impact on water quality was a significant concern. While laboratory studies suggest that in extreme conditions, chemicals from TDA can leach into groundwater in concentrations that exceed drinking water standards, field studies conducted since then—including a MnDOT project—have mitigated this concern somewhat and indicate that TDA fills should not affect off-site soil or groundwater quality. TDA use in water, however, is still not recommended.” A small infiltration basin is also proposed on the north side of the building to provide abstraction and water quality treatment prior to discharging to the onsite wetland. One delineated wetland is located onsite north of the proposed building. Riley Creek is located along the northern site boundary. The 100-year floodplain of Riley Creek was found to inundate a portion of the property along the northern property boundary at varying elevations between approximately 945 to 952 feet (NGVD29). Because Riley Creek and a wetland are downgradient from the proposed land disturbing activities, wetland and creek buffer requirements apply to the proposed project. The project site information is summarized below: Project Site Information Area (acres) Total Site Area 3.6 Existing Impervious 0.01 Disturbed Impervious Area 0.01 Proposed Impervious Area 1.26 Change in Impervious Area 1.25 Regulated Impervious Area 1.26 Total Disturbed Area 2.88 Rule Specific Permit Conditions Rule B: Floodplain Management and Drainage Alterations Because the proposed project involves constructing a new outfall as well as grading and rip rap installation below the 100-year flood elevation of Riley Creek (945 NGVD29), the project activities must Page | 4 conform to the RPBCWD’s Floodplain Management and Drainage Alterations rule (Rule B). The 100-year flood elevations of Riley Creek along the northern site boundary are displayed on the plans (Rule B, Subsection 4.2). The proposed low floor elevation of the building (958 feet) will be constructed in accordance with Rule J, Subsection 3.6 (Rule B, Subsection 3.1). The plans provide a cross-section showing the proposed outfall including existing and proposed ground surface below the 100-year floodplain. Because the project proposes to match existing elevations at the proposed outfall, the post-development conditions will result in no net change in the existing floodplain storage. Thus, the project conforms to Rule B, Subsection 3.2. The proposed outfall includes a riprap stilling basin at the flared end section outlet prior to discharge into Riley Creek, thus reducing the velocity of the stormwater outflow to not alter the creek flows or channel stability in accordance with Rule B, Subsection 3.3. The Applicant submitted an erosion control plan in conformance with Rule C, per Rule B, Subsection 3.5. A note on the plans indicates that activities must be conducted to minimize the potential transfer of aquatic invasive species conforming to Rule B, Subsection 3.5. To conform to the RPBCWD Rule B requirements the following stipulation is recommended: B1. Proof that drainage and flowage easements over all land below the 100-year flood elevation have been conveyed to the municipality with jurisdiction, if required, needs to be submitted prior to project close out. Rule C: Erosion Prevention and Sediment Control Because the project will alter more than 50 cubic yards of material, the project must conform to the requirements in the RPBCWD Erosion Prevention and Sediment Control rule (Rule C, Subsection 2.1). The erosion and sediment control plans prepared by Civil Site Group include installation of perimeter control (including redundant perimeter controls at the proposed wetland and creek buffer), inlet protection for storm sewer catch basins, a rock construction entrance, protection of stormwater management facilities, placement of a minimum of 6 inches of topsoil, decompaction of pervious areas compacted during construction, and retention of native topsoil onsite. To conform to RPBCWD Rule C requirements the following revisions are needed: C1. The Applicant must provide the name and contact information of the general contractor responsible for the site. RPBCWD must be notified if the responsible party changes during the permit term. This information is required prior to issuance of the permit. Page | 5 Rule D: Wetland and Creek Buffers Because the proposed work triggers a permit under RPBCWD Rules B, G, and J and Riley Creek and the onsite wetland are downgradient from the proposed construction activities, Rule D, Subsections 2.1a and 3.1 require buffer along the downgradient edge of the creek and wetland. Rule D, Subsections 3.1b and 3.1c require buffer on the edge of the wetland that is downgradient from the activity and on a streambank downgradient from the land-disturbing activity in accordance with Rule D, Subsection 3.2. No land disturbing activities are proposed within the onsite wetland. Using the MNRAM functions and values assessment dated February 4, 2020 the onsite wetland was determined to be medium value. The land-disturbing activities are located upgradient from the medium value wetland requiring a 40-foot average, 20-foot minimum buffer width (Rule D, Subsection 3.2b.iii). RPBCWD Rule D, Subsection 3.2.b.v requires an average buffer width of 50 feet from the creek centerline, minimum 30 feet for a public waters watercourse. The Applicant provided a buffer plan and marker location map confirming that the proposed buffer area extends the required average widths. As shown in the table below, the required buffer width for the onsite wetland and Riley Creek conform to Rule B, Subsection 3.2. Regulated Feature RPBCWD Wetland Value Required Minimum Width1 (ft) Required Average Width1 (ft) Provided Minimum Width (ft) Provided Average Width (ft) Riley Creek N/A 30 50 73.2 84.7 Onsite Delineated Wetland Medium 20 40 20.0 40.2 1 Average and minimum required buffer width based on Rule D, Subsection 3.2.b. The Applicant is proposing revegetating disturbed areas within the proposed buffer with native vegetation in conformance with Rule D, Subsection 3.3. The plans identify buffer marker locations and include a design detail in conformance with design and text provided by the District (Rule D, Subsection 3.4). A note is included on the plan sheet indicating the project will be constructed so as to minimize the potential transfer of aquatic invasive species (e.g., zebra mussels, Eurasian watermilfoil, etc.) to the maximum extent possible conforming to Rule D, Subsection 3.6. To conform to the RPBCWD Rule D the following revisions are needed: Page | 6 D1. The plans and specifications must identify the installation date of the buffer markers, which must be set to ensure protection of buffer area during and after land-disturbing activities. This information is needed prior to issuance of the permit (Rule D, Subsection 3.4a) D2. Buffer areas and maintenance requirements must be documented in a declaration recorded after review and approval by RPBCWD in accordance with Rule D, Subsection 3.5. The maintenance declaration must also include an exhibit clearly showing the buffer area and monument locations. Rule G: Waterbody Crossings and Structures Because the project proposes a new outfall structure along the bank of Riley Creek, a public watercourse, the project requires conformance with RPBCWD’s Waterbody Crossings and Structures Rule (Rule G). The proposed work falls within the scope of Minnesota Department of Natural Resources General Permit #2015-1192. (Rule F: Stormwater and Streambank Stabilization is not triggered because the riprap being installed in bank of the creek is to prevent erosion moreso than stabilize the bank and the relevant Rule F criteria are covered here, under Rule G.) This work represents a demonstrated public benefit by maintaining existing drainage patterns and reducing pollutant loading to Riley Creek (Rule G, Subsection 3.1a). The project plans incorporate a detail of the proposed outfall that require a small stilling basin be provided prior to the discharge entering Riley Creek. In addition, site runoff is conveyed to sump manholes and the proposed filtration basin with subsurface infiltration for entrapment of floatables, sedimentation, runoff retention and reduction of peak runoff rates to less than existing condition before the discharging to the creek, thus the design is in conformance with Rule G, Subsection 3.3. Placement of the proposed outfall structure represents the minimal impact solution by minimizing concentrated overland flow which would exacerbate soil erosion potential and promote sediment discharge into the creek from upgradient sources. The proposed outfall design minimizes the discharge velocity by including a drop manhole structure and limits the site disturbance adjacent to the creek, both of which minimize erosion potential and thus meet criteria in Rule G, Subsection 3.5a. The project proposes to match existing elevations along the creek at the outfall to minimize encroachment and change along the creek. In addition, a portion of the stormwater runoff from the site is conveyed to the City of Chanhassen storm sewer system to reduce flow at the outfall. Thus, design is in conformance with Rule G, Subsection 3.5b. As discussed in the Rule B narrative above, the propose project will comply with the District floodplain rule, as required by subsection 3.5c. Based on the designed outfall discharge velocity, outlet invert elevation, energy dissipation design, riprap construction and proposed stabilization methods, the proposed outfall structure is not reasonably Page | 7 likely to cause adverse effects to water quality and the physical or biological character of the waterbody, thus conforming to Rule G, Subsection 3.5d. The project SWPPP includes a note directing the contractor that no work affecting the bed or banks of a protected water shall occur between March 15 and June 15 (Rule G, Subsection 3.7a). Disturbed areas near and along the banks will be immediately stabilized after completion of permitted work and revegetated as soon as growing conditions allow (Rule G, Subsection 3.7b). A note is included on the plan sheet indicating the project will be constructed so as to minimize the potential transfer of aquatic invasive species (e.g., zebra mussels, Eurasian watermilfoil, etc.) to the maximum extent possible (Rule G, Subsection 3.7c). Plans submitted confirm that riprap is sized appropriately in relation to the erosion potential. Riprap is sized at 6 inches in diameter which is appropriately sized to withstand the designed discharge velocity of 3.5 feet per second, thus conforming to Rule F, Subsection 3.3b (i). Plans submitted confirm the proposed outfall construction along the bank of Riley Creek will follow the natural alignment of the bank and will not cover emergent vegetation (Rule F, Subsection 3.3b (ii) and 3.3b (iv)). The plans and details indicate that a transitional layer consisting of graded gravel, at least 6 inches deep with an appreciate geotextile fabric will be placed between the existing shoreline and rip rap, thus conforming to Rule F, Subsection 3.3b (iii). As shown in the riprap detail in the plans, the riprap is proposed to extend to the area around the top of the pipe below the Riley Creek 100-year floodplain elevation of 945 NGVD29, consistent with Rule F, Subsection 3.3b (v). The riprap design reflects energy dissipation and stabilization necessary to minimize erosion at the streambank and is not placed for cosmetic purposes per Rule F, Subsection 3.3b (vi). To conform to the RPBCWD Rule G the following revisions are needed: G1. Permit applicant must provide a draft maintenance declaration for the outfall structure, in accordance with Rule G, Section 5. Rule J: Stormwater Management Because the project will disturb 2.9 acres of surface area, the project must meet the criteria of RPBCWD’s Stormwater Management rule (Rule J, Subsection 2.1). The project proposes construction of three stormwater management facilities to provide stormwater quantity, volume and rate quality control. A filtration basin proposed at the eastern side of the property will provide water quality, rate control and abstraction for the eastern portion of the proposed parking areas and landscaping. The filtration basin has an elevated underdrain system to promote infiltration. A subsurface filtration system with elevated draintile is proposed beneath a portion of the parking area and will accept runoff from the western portion of the parking area and the building roof. The subsurface system will consist of a tire derived aggregate (TDA) field which will allow for infiltration beneath an outlet that discharges to the City of Chanhassen storm sewer system along West 78th Street. Page | 8 A small infiltration basin is also proposed on the north side of the building to provide abstraction and water quality treatment prior to discharging to the onsite wetland. Pretreatment for the filtration basin is provided by a Rain Guardian Turret device which separates sediment from water flowing into the basin. Pretreatment to the subsurface TDA field infiltration basin is provided by sump catch basins while pretreatment to the small northern basin is provided by a vegetated filter strip. Rate Control In order to meet the rate control criteria listed in Subsection 3.1.a, the 2-, 10-, and 100-year post development peak runoff rates must be equal to or less than the existing discharge rates at all locations where stormwater leaves the site. The Applicant used a HydroCAD hydrologic model to simulate runoff rates for pre- and post-development conditions for the 2-, 10-, and 100-year frequency storm events using a nested rainfall distribution, and a 100-year frequency, 10-day snowmelt event. The existing and proposed 2-, 10-, and 100-year frequency discharges from the site are summarized in the table below. Modeled Discharge Location 2-Year Discharge (cfs) 10-Year Discharge (cfs) 100-Year Discharge (cfs) 10-Day Snowmelt (cfs) Ex Prop Ex Prop Ex Prop Ex Prop EX1/PR1 (Wetland/Creek) 3.2 2.2 6.7 4.5 13.9 9.4 0.5 0.3 EX2/PR2 (Adjacent Property) 0.5 0.3 1.1 0.7 2.3 1.4 0.1 <0.1 EX3/PR3 (78th Street) 0.7 0.4 1.4 0.6 2.9 1.2 0.1 <0.1 The proposed stormwater management plan will provide rate control in compliance with the RPBCWD requirements for the 2-, 10-, and 100-year events. Thus, the proposed project meets the rate control requirements in Rule J, Subsection 3.1a. Volume Abstraction Subsection 3.1.b of Rule J requires the abstraction onsite of 1.1 inches of runoff from all impervious surface of the parcel. An abstraction volume of 5,049 cubic feet is required from the 1.26 acres (55,080 square feet) of impervious area on the project for volume retention. The Applicant proposes three stormwater management facilities to provide volume abstraction, a filtration basin with subsurface infiltration below an elevated underdrain, a subsurface TDA field with a subsurface infiltration area below the TDA field outlet, and a small infiltration basin north of the proposed building. Soil borings performed by Haugo Geotechnical Services, Inc. dated January 5, 2018 show that soils onsite typically consist of Sandy Lean Clay fill with trace organic materials, gravel and wood over Sandy Lean Clay (CL) glacial till. The MN Stormwater Manual indicates an infiltration rate of 0.06 inches per hour for Page | 9 sandy lean clay is appropriate based on the identification of Hydrologic Soil Group (HSG) Type D soils onsite. Soil borings performed by Haugo Geotechnical show groundwater identified in the soil borings at elevations ranging from 946 feet to 950 feet. Groundwater was not encountered in the soil boring taken at the location and elevation of the proposed filtration basin at the eastern side of the property. Groundwater was encountered in the soil borings located near the proposed subsurface infiltration system ranging from approximately 946 feet to 950 feet. The bottom of the proposed subsurface infiltration system is at an elevation of 963.00 feet. This indicates that groundwater is at least 3 feet below the bottom of the proposed stormwater management systems (Rule J, Subsection 3.1.b.ii.2). An abstraction volume of 5,787 cubic feet is provided by the three proposed infiltration systems. The table below summarizes the volume abstraction required and the volume abstraction achieved by the proposed stormwater management facilities on the site. Stormwater Management System Required Abstraction Depth (inches) Required Abstraction Volume (cubic feet) Provided Abstraction Depth (inches) Provided Abstraction Volume (cubic feet) Filtration/Infiltration Basin, East End of Site 1.1 669 2.6 1,557 Subsurface TDA Filtration/Infiltration System, Beneath West Parking Area 1.1 4,095 1.1 4,104 Small north infiltration basin 1.1 72 1.1 126 Total Site 1.1 5,049 1.2 5,787 The RPBCWD Engineer concurs that the volume abstraction provided by the proposed stormwater management facilities is in compliance with Rule J, Subsection 3.1b (i). Pretreatment of runoff must be provided in accordance with the guidance in the Minnesota Stormwater Manual. Pretreatment for the filtration basin is provided by a Rain Guardian Turret device which separates sediment from water flowing into the basin. Pretreatment to the subsurface TDA field infiltration basin is provided by sump catch basins. Pretreatment devices are in conformance with Rule J, Subsection 3.1b.ii.1. The proposed stormwater facilities provide adequate surface area to drawdown the abstraction volumes within the required 48 hour period, thus conforming with Rule J, Subsection 3.1.b.ii.3. While the geotechnical report lists a suggested infiltration rate of 0.06 inches per hour based on soil classification, it does not contain infiltration or hydraulic conductivity testing results at the bottom of the infiltration facilities as required by Rule J, Subsection 3.1.b.ii.c. The applicant must submit documentation verifying the infiltration capacity of the soils and that the volume control capacity is calculated using the measured infiltration rate prior to project close-out. If infiltration capacity is less Page | 10 than needed to conform with the volume abstraction requirement in subsection 3.1b, design modifications to achieve compliance with RPBCWD requirements will need to be submitted (in the form of an application for a permit modification or new permit). Water Quality Management Subsection 3.1.c of Rule J requires the Applicant provide volume abstraction in accordance with 3.1b or least 60 percent annual removal efficiency for total phosphorus (TP), and at least 90 percent annual removal efficiency for total suspended solids (TSS) from site runoff, and no net increase in TSS or TP loading leaving the site from existing conditions. Because the BMPs proposed by the applicant provide more volume abstraction than is require in accordance with 3.1b, the engineer concurs with the modeling, and finds that the proposed project is in conformance with Rule J, Subsection 3.1.c. Low floor Elevation No structure may be constructed or reconstructed such that its lowest floor elevation is less than 2 feet above the 100-year event flood elevation of a waterbody or stormwater management facility. No stormwater management system may be constructed or reconstructed in a manner that brings the low floor elevation of an adjacent structure into noncompliance according to Rule J, Subsection 3.6. The low floor elevation of the proposed building and the adjacent stormwater management feature or waterbody are summarized below. Stormwater Management Facility or Waterbody Low Floor Elevation of Proposed Building (feet) 100-year Event Flood Elevation of Adjacent Stormwater Facility or Waterbody (feet) Freeboard (feet) Filtration Basin 958.00 953.89 4.11 Subsurface TDA Field Infiltration Basin 958.00 965.02 3.18 Riley Creek 958.00 952.1-945.00 13.00-5.9 While the RPBCWD Engineer concurs that the low floor of the proposed building is in compliance with Rule J, Subsection 3.6a relative to the 100-year elevations on Riley Creek, the proposed filtration basin, and the subsurface TDA field infiltration basin, there is only 0.44 feet separation between the proposed low floor and the emergency overflow from the small northern infiltration basin. No adjacent habitable buildings will be brought into noncompliance with standards in Rule J, Subsection 3.6b. Thus, to conform to the RPBCWD Rule J, Subsection 3.6 the following revision is needed: J1. Permit applicant must revise the design to provide at least one foot separation between the emergency overflow of the northern information basin and the proposed low floor of the structure and provide updated drawings. Page | 11 Maintenance Subsection 3.7 of Rule J requires the submission of a maintenance plan. All stormwater management structures and facilities must be designed for maintenance access and properly maintained in perpetuity to assure that they continue to function as designed. The stormwater management facilities include the filtration basin on the east side of the property, the subsurface TDA field infiltration system, small infiltration basin north of the building, sump manhole structures and the Rain Guardian Turret device. The Applicant must provide a draft maintenance and inspection declaration in conformance with Rule J, Subsection 3.7, for approval by RPBCWD staff prior to recordation. To conform to the RPBCWD Rule J the following revisions are needed: J2. Permit applicant must provide a maintenance and inspection declaration as required by Rule J, Subsection 3.7. A maintenance declaration template is available on the permits page of the RPBCWD website (http://www.rpbcwd.org/permits/). A draft declaration must be provided for District approval prior to recordation as a condition of issuance of the permit. Chloride Management Subsection 3.8 of Rule J requires the submission of chloride management plan that designates the individual authorized to implement the chloride management plan and the MPCA-certified salt applicator engaged in implementing the plan. To close out the permit and release the $5,000 in financial assurance held for the purpose of chloride management, the permit applicant must provide a chloride management plan that designates the individual authorized to implement the chloride management plan and the MPCA-certified salt applicator engaged in implementing the plan at the site. Wetland Protection Subsection 3.10 of Rule J requires that no activity subject to this rule may alter a site in a manner that alters the bounce in water level, duration of inundation, or change the runout elevation in the subwatershed in which the site is located for any wetland receiving discharge directly from the site. The wetland is downgradient from land disturbing activities and receives sheet flow discharge from the patio on the north side of the proposed building and landscaping. The Applicant used a HydroCAD hydrologic model to simulate runoff rates and flow depths for pre- and post-development conditions for applicable storm events specified in Table J1. Rule J, Subsection 3.10 identifies the permitted bounce for a 10-year event for a medium value wetland to be existing levels plus/minus 1.0 foot. The modeled inflow depths for the wetland pre- and post-development conditions for a 10-year event are 2.27 inches and 2.35 inches, respectively, providing 0.08 inches of bounce. Table J1 identifies a permitted change of 0 to 1.0 feet for runout control elevation change for a medium value wetland. Because no grading is proposed at the wetland outlet (approximately 951.80 feet at the northernmost elevation of the wetland boundary), the runout elevation will not change. Table J1 identifies the inundation period for 1- and 2-year events for a medium value wetland as the existing period plus two days, and the existing period plus 14 days for a 10-year event. The submitted hydrologic Page | 12 models demonstrate that the duration of inundation has not been increased from existing conditions. The submitted materials demonstrate, and RPBCWD engineers concurs, that project is in conformance with Rule J, Subsection 3.10a for the medium value wetland at the site. Rule J, Subsection 3.10b requires that treatment of runoff to wetlands meet at the water quality treatment criteria in Rule J, subsection 3.1c. The Applicant is proposing the construction of a small infiltration basin to abstract 1.1 inches of runoff from the tributary impervious area to demonstrate conformance with the wetland water quality protection criteria. Because the small infiltration basin proposed by the applicant provides the volume abstraction required in accordance with 3.1b, the engineer finds that the proposed project is in conformance with Rule J, Subsection 3.10b. Rule L: Permit Fee Deposit: The RPBCWD permit fee schedule adopted in February 2020 requires permit applicants to deposit $3,000 to be held in escrow and applied to cover the $10 permit-processing fee and reimburse RPBCWD for permit review and inspection-related costs and when a permit application is approved, the deposit must be replenished to the applicable deposit amount by the applicant before the permit will be issued to cover actual costs incurred to monitor compliance with permit conditions and the RPBCWD Rules. A permit fee deposit of $3,000 was received on January 22, 2020. Rule M: Financial Assurance: Rules C: Silt fence and bio-logs: 4,000 L.F. x $2.50/L.F. = ............................................................... $10,000 Inlet protection: 9 x $100 = ..................................................................................................... $900 Rock Entrance: 1.0 x $900 = .................................................................................................... $900 Restoration: 2.9 acres x $2,500/acre = ................................................................................ $7,250 Rule D: Wetland and Creek Buffers: $5,000= .................................................................................. $5,000 Rules G & J: Stormwater Management Facilities and Creek Outfall: $305,197 x 125% of engineer’s opinion of cost= ........................................................................................................................... $381,496 Chloride Management Plan: $5,000 ................................................................................................. $5,000 Contingency (10%) .......................................................................................................................... $41,055 Total Financial Assurance .............................................................................................................. $451,601 Applicable General Requirements: 1. The RPBCWD Administrator shall be notified at least three days prior to commencement of work. 2. Construction shall be consistent with the plans and specifications approved by the District as a part of the permitting process. The date of the approved plans and specifications is listed on the permit. Page | 13 3. Return or allowed expiration of any remaining surety and permit close out is dependent on the permit holder providing proof that all required documents have been recorded and providing as-built drawings that show that the project was constructed as approved by the Managers and in conformance with the RPBCWD rules and regulations. Findings 1. The proposed project includes the information necessary, plan sheets and erosion control plan for review. 2. The proposed project will conform to Rules B, C, D, G and J if the Rule Specific Permit Conditions listed above are met. 3. Under Minnesota Department of Natural Resources General Permit 2015-1192 (attached to this report), approval of work under RPBCWD rule(s) G constitutes approval under applicable DNR work in waters rules. Compliance with conditions on approval and payment of applicable fees, if any, are necessary to benefit from general permit approval and the responsibility of the applicants. Recommendation: Approval, contingent upon: 1. Continued compliance with General Requirements 2. Financial Assurance in the amount of $451,601. 3. The applicant providing the name and contact information of the general contractor responsible for the site. 4. Permit applicant must revise the design to provide at least one foot separation between the emergency overflow of the northern information basin and the proposed low floor of the structure and provide updated drawings. 5. Receipt in recordation a maintenance declaration for the stormwater management facilities, buffer areas and proposed outfall structure. Drafts of all documents to be recorded must be approved by the District prior to recordation. 6. The permit fee deposit must be replenished to $3,000 before the permit will be issued to cover actual costs incurred to monitor compliance with permit conditions and the RPBCWD Rules. By accepting the permit, when issued, the applicant agrees to the following stipulations: 1. The applicant provides proof of recordation that drainage and flowage easements over all land below the 100-year flood elevation have been conveyed to the municipality with jurisdiction, if required. 2. Per Rule D, Subsection 3.4.a. the plans and specifications must identify the installation date, which must be set to ensure protection of buffer area during and after land-disturbing activities. Page | 14 This information is required to be submitted by the contractor once the contractor has been determined. 3. Per Rule J, Subsection 3.1.b.ii measured infiltration capacity of the soils at the bottom of the infiltration systems must be provided. The applicant must submit documentation verifying the infiltration capacity of the soils and that the volume control capacity is calculated using the measured infiltration rate. If infiltration capacity is less than needed to conform with the volume abstraction requirement in subsection 3.1b, design modifications to achieve compliance with RPBCWD requirements will need to be submitted (in the form of an application for a permit modification or new permit). 4. Per Rule J Subsection 4.5, upon completion of the site work, the permittee must submit as-built drawings demonstrating that at the time of final stabilization, stormwater facilities (including surface and underground features) conform to design specifications as approved by the District. 5. The work on the Moments of Chanhassen parcel under the terms of permit 2020-003, if issued, must have an impervious surface area and configuration materially consistent with the approved plans. Design that differs materially from the approved plans (e.g., in terms of total impervious area) will need to be the subject of a request for a permit modification or new permit, which will be subject to review for compliance with all applicable regulatory requirements. 6. To close out the permit and release the $5,000 in financial assurance held for the purpose of the chloride management, the permit applicant must provide a chloride management plan that designates the individual authorized to implement the chloride management plan and the MPCA-certified salt applicator engaged in implementing the plan at the site. 7. Replenish the permit fee deposit to the original amount or such lesser amount as the RPBCWD administrator deems sufficient within 45 days of receiving notice that such deposit is due in order to cover continued actual costs incurred to monitor compliance with permit conditions and the RPBCWD Rules. 8. The Department of Natural Resources General Permit #2015-1192 applies to authorize the work in Riley Creek as long as the permittee complies with the conditions of the general permit, which is attached to this report. P ow e r s B l v d LakeDr E ButteCt HunterDr Longacres Dr AcornLaBrinker St Mallo ryCtUtica LaW 78th St Stone Creek DrPark Ct MaplewoodTerW 78th St P o n t i a c C i rShawneeLa U p l a n d C i r TecumesehLaRedman LaAudobon RdWind DrTimberwood DrFawn Hill RdMcglynn Dr Park RdSto n eCr ee k D r Park P l West Lake Ct W 78th St Lake Dr WPark DrWalnut Cv Majestic Way Powers BlvdMotor Plex CtAudobon RdGalpin BlvdPr a i r i e F l o w e r B l v d Coulter Blvd ¨©117 456717 456717 5 5 Chanhassen Lake Lucy Lake Ann BluffCreek RileyCreek Barr Footer: ArcGIS 10.7.1, 2020-03-25 11:45 File: I:\Client\RPBC_WD\Work_Orders\Monthly_General_Services\Permitting\Maps\2020\2020-003 Moments of Chanhassen.mxd User: mbs2 Permit Location Map MOMENTS OF CHANHASSENPermit 2020-003Riley Purgatory Bluff CreekWatershed District !;N 0 1,000 Feet SITE 30.0+/-32.0 +/-43"W 399.54S01°20'39"W 200.00N63°20'43"E 100.00N01°20'42"E 235.075.70S74°17'30"W326.13Δ=18°35'40"R=1004.93N87°06'49"W 228.90PROPERTY LINEPROPERTY LINEWETLANDBUILDING SUMMARY: 48 UNITS17 UG PARKING SPACESBUILDING FOOTPRINT 33,061 SFWWETLANNDHEAVY DUTY BIT PVMT.CONCRETESIDEWALK,TYP.ADA ACCESSIBLE PARKINGSPOT W/ STRIPING SIGNAGEAND CURB RAMPHCHC6' CURB TAPER, B612 TORIBBON CURBSEGMENTAL RETAINING WALL,COORD. STYLE & TYPE W/ARCH. & OWNER, SHOPDRAWINGS REQ'D. SEEGRADING PLAN FOR WALLTOP/BOTTOM ELEVATIONS.SEGMENTAL RETAINING WALL,COORD. STYLE & TYPE W/ARCH. & OWNER, SHOPDRAWINGS REQ'D. SEEGRADING PLAN FOR WALLTOP/BOTTOM ELEVATIONS.6' CURB TAPER, B612 TORIBBON CURBB612 CURB & GUTTER, TYP.ASPHALT TRAIL CROSSING W/HEAVY DUTY PVMT, SEEGRADING.CONC. DRIVEWAY APRON PERCITY STANDARD DETAIL 5208,SHEET C5.0MATCH EX. CURB & GUTTERCONCRETE UTILITY PADS,ENSURE TOP OF PAD IS MIN. 6"ABOVE ADJ. GRADE, COORD. W/ARCH. & ELECTRICAL.HEAVY DUTY BIT PVMT.MONUMENT SIGNWETLAND BUFFER SIGNAGESPACED 60.0', SEE SIGNDETAIL ON SW1.2, TYP.FILTRATION BASIN 1EOF=956.20OUTLET RIM (12" VERTICALORIFICE)=953.95BOTTOM=952.60DRAINTILE (6" PERF. PVC) IE=951.20PLANTING MEDIUM IE=950.60100-YR HWL=953.89INSTALL PER DETAIL W/ 24" SAND BELOWBOTTOM & ROCK SURROUNDINGDRAINTILESEE LANDSCAPE AND GRADINGSEE STORMWATER REPORT FOR VOLUMEAND RATE CONTROL DETAILSPROPOSED 100-YR HWLDRAINAGE & FLOWAGEEASEMENTCONTRACTOR SHALL SUBMITPROPOSED DEMOLITION,STAGING AND CLEAN-UPAREAS TO CITY.LIGHT DUTY BIT PVMT, TYP.RAIN GARDEN/DEPRESSEDGRADEBOTTOM=957.32BOTTOM AREA=528 SFOVERFLOW ELEVATION=957.56SEE GRADING & LANDSCAPERAIN GUARDIAN, SEE UTILITYPLAN & DETAILS ON SHEETC5.3.PROPOSED AVERAGED WETLAND BUFFER: 39,714 SFPPPPRPRPROROROOPOPOPOPOPOOSOSOSESESEEDEDED D AD AAVAVAVAVEVEVERERERRARARAGAGAGGEGEGED WD WWWEWEWETETETLTLTLATLALAANANANDNDNDD D BD BBUBUBUUFUFUFFFFFFEFEFERERERR:R: R: 3: 3393939,9,79,77171471414 4 S4 S SSFSFSFFBY CODE WETLAND BUFFER AREA: 38,248 SF593.20PROPERTY LINEcivilsitegroup.comCOPYRIGHT 2018 CIVIL SITE GROUP INC.cISSUE/SUBMITTAL SUMMARYDATEDESCRIPTIONMOMENTS OF CHANHASSEN1660 ARBORETUM BLVD, CHANHASSEN, MN 5531716258 KENYON AVE, LAKEVILLE, MN 55004TMSC OF CHANHASSEN LLCPROJECT............PROJECT NUMBER: 1722744263Matthew R. PavekLICENSE NO.DATEI HEREBY CERTIFY THAT THIS PLAN,SPECIFICATION, OR REPORT WASPREPARED BY ME OR UNDER MY DIRECTSUPERVISION AND THAT I AM A DULYLICENSED PROFESSIONAL ENGINEERUNDER THE LAWS OF THE STATE OFMINNESOTA.02/14/2001/22/20 WATERSHED SUBMITTAL02/04/20 SITE PLAN02/18/20 CITY/WATERSHED RESUBMITTAL03/05/20 WATERSHED RESUBMITTAL....01/06/20 CITY SUBMITTALDRAWN BY:RL, JSREVIEWED BY:PSPRELIMINARY:NOT FORCONSTRUCTIONREVISION SUMMARYDATEDESCRIPTIONC2.0SITE PLAN............SITE AREA TABLE:SITE LAYOUT NOTES:SITE PLAN LEGEND:NKnow what'sR WETLAND BUFFER EXHIBIT TRUCK TURNING EXHIBIT (1"=40') 30.0+/-32.0 +/-S01°20'43"W 399.54S01°20'39"W 200.00N63°20'43"E 100.00N01°20'42"E 235.075.70S74°17'30"W326.13Δ=18°35'40"R=1004.93N87°06'49"W 228.90"W 593.20WETLANDWWETLTANNDFILTRATION BASIN 1EOF=956.20OUTLET RIM (12" VERTICALORIFICE)=953.95BOTTOM=952.60DRAINTILE (6" PERF. PVC) IE=951.20PLANTING MEDIUM IE=950.60100-YR HWL=953.89INSTALL PER DETAIL W/ 24" SAND BELOWBOTTOM & ROCK SURROUNDINGDRAINTILESEE LANDSCAPE AND GRADINGSEE STORMWATER REPORT FOR VOLUMEAND RATE CONTROL DETAILSRAIN GARDEN/DEPRESSEDGRADEBOTTOM=957.32BOTTOM AREA=528 SFOVERFLOW ELEVATION=957.56SEE GRADING & LANDSCAPEcivilsitegroup.comCOPYRIGHT 2018 CIVIL SITE GROUP INC.cISSUE/SUBMITTAL SUMMARYDATEDESCRIPTIONMOMENTS OF CHANHASSEN1660 ARBORETUM BLVD, CHANHASSEN, MN 5531716258 KENYON AVE, LAKEVILLE, MN 55004TMSC OF CHANHASSEN LLCPROJECT............PROJECT NUMBER: 1722744263Matthew R. PavekLICENSE NO.DATEI HEREBY CERTIFY THAT THIS PLAN,SPECIFICATION, OR REPORT WASPREPARED BY ME OR UNDER MY DIRECTSUPERVISION AND THAT I AM A DULYLICENSED PROFESSIONAL ENGINEERUNDER THE LAWS OF THE STATE OFMINNESOTA.02/14/2001/22/20 WATERSHED SUBMITTAL02/04/20 SITE PLAN02/18/20 CITY/WATERSHED RESUBMITTAL03/05/20 WATERSHED RESUBMITTAL....01/06/20 CITY SUBMITTALDRAWN BY:RL, JSREVIEWED BY:PSPRELIMINARY:NOT FORCONSTRUCTIONREVISION SUMMARYDATEDESCRIPTIONC3.0GRADING PLAN............GENERAL GRADING NOTES:GRADING PLAN LEGEND:GROUNDWATER INFORMATION:CITY OF CHANHASSEN GRADING NOTES:EROSION CONTROL NOTES:NKnow what'sR EOF=1135.52EOF=968.85EOF=969.13 30.0+/-32.0 +/-195.00361.00S01°20'43"W 399.54S01°20'39"W 200.00N63°20'43"E 100.00N01°20'42"E 235.075.70S74°17'30"W326.13Δ=18°35'40"R=1004.93N87°06'49"W 228.90S01°20'42"W 593.20WETLANDWWETLTANNDFILTRATION BASIN 1EOF=956.20OUTLET RIM (12" VERTICALORIFICE)=953.95BOTTOM=952.60DRAINTILE (6" PERF. PVC) IE=951.20PLANTING MEDIUM IE=950.60100-YR HWL=953.89INSTALL PER DETAIL W/ 24" SAND BELOWBOTTOM & ROCK SURROUNDINGDRAINTILESEE LANDSCAPE AND GRADINGSEE STORMWATER REPORT FOR VOLUMEAND RATE CONTROL DETAILSRAIN GARDEN/DEPRESSEDGRADEBOTTOM=957.32BOTTOM AREA=528 SFOVERFLOW ELEVATION=957.56SEE GRADING & LANDSCAPESTUB 6" SANITARY TO 5'FROM BUILDINGIE @ STUB=955.03COORD. W/MECH'L30 LF 6" PVC SCH. 40SANITARY SERVICE @1.00%SAN. MH 3RE=968.00±IE=954.73DIRECTIONAL BORE 186LF 6" PVC SDR 35SANITARY SERVICE @1.00%SAN. MH 2RE=969.20±IE=952.87DIRECTIONAL BORE 300LF 6" PVC SDR 35SANITARY SERVICE @1.00%6" CORE DRILL CONNECTION W/INTRAFLOW INSIDE DROP TO EX.SANITARY INTERCEPTOR MANHOLEEX. RE=970.80EX. IE=928.10 (FIELD VFY.)PR. IE CORE DRILL=949.87PR. IE INSIDE DROP ELBOW=928.20 (0.1'ABOVE EX. IE)POINT ELBOW TOWARD DOWNSTREAM.SECURE INSIDE DROP WITHINMANHOLE, ENSURE WATER-TIGHTPENETRATION OF MANHOLE.STUB 8" C900COMBINEDDOMESTIC/FIREWATER SERVICETO 5' FROM BLDG.,COORD. W/ MECH'LFOR FINAL SIZINGAND LOCATION.WET TAP 8"COMBINED C900DOMESTIC/FIREWATER SERVICESTO EX. 12" WATERMAIN, COORD. W/CITY. COORD. W/MECH'L FOR FINALSIZING PRIOR TOCONSTRUCTION.COORDINATION W/CITY MUST BE48-HOURS PRIORTO TAP.CONTRACTOR TO FIELD VERIFY ALL SMALL UTILITIES.CONTACT ENGINEER IMMEDIATELY WITH ANYCONFLICTS.OCS 2RE=955.95IE (12" VERTICAL ORIFICE)=953.95IE (N, 12")=948.20IE (DRAINTILE)=951.20SEE DETAIL C5.1/26" PERF. PVC DRAINTILENETWORKIE=951.20CB 5RE=968.63IE=964.63SUMP IE=960.63RAIN GUARDIAN 3RE=956.81IE=955.81INSTALL RIP RAP DOWN TOBASIN BOTTOM. SEE DETAILSON SHEET C5.3.62 LF 12" HDPE @ 2.00%STUB 12" PVC BUILDING STORMROOF DRAIN TO 5' FROM BLDG.,COORD. W/ MECH'L.STUB IE=964.69BLDG IE=964.79DRAINTILE CLEANOUT RISERCAP RISER @ 1' ABOVEBOTTOM OF BASIN, TYP.OUTLET CONTROLSTRUCTURE 3RE=969.00±IE=963.4810 LF 12" RCP @ 0.00%OPEN ENDED RCP,IE=963.4837 LF 6" PVC SDR 35 @2.00%CORE DRILLCONNECTION TO EX.CATCH BASIN.EX. IE=962.00 (FIELDVFY.)PR. IE=962.74CB 4RE=968.39IE=964.39SUMP IE=960.3910 LF 12" RCP @ 2.00%OPEN ENDED RCP,IE=964.1910 LF 12" RCP @ 2.00%OPEN ENDED RCP,IE=964.43UNDERGROUND TDA FIELDINFILTRATION BASINFIELD IE=963.00FIELD TOP=965.50FOOTPRINT=17,100 SF (BOTTOM)FIELD OUTLET (6" @ OCS 1) IE=963.48100-YR HWL=965.02SEE SECTION DETAILINSTALL & COMPACT TDA PERMANUFACTURER'S AND GEOTECHNICALENGINEER'S GUIDANCESEE STORMWATER REPORT FORVOLUME AND RATE CONTROL DETAILS10 LF 12" RCP @ 2.00%OPEN ENDED RCP,IE=964.49DROP STRUCTURE & OUTFALL 1RE=952.00±IE (S)=946.96IE (N)=944.11SEE DETAIL C5.1/322 LF 12" HDPE @ 0.50%STMH 7RE=970.60±IE=964.69CONTRACTOR TO PERFORM A MINIMUMOF ONE DOUBLE-RING INFILTRATIONTEST PER ASTM D3385 STANDARDWITHIN THE LIMITS OF EACHSTORMWATER BMP. REPORT FINDINGSTO ENGINEER & RPBCWDFES 1IE=944.00EXIT VELOCITY=3.5 FPSINSTALL 2.8 CY CLASS II RIPATOP 1.4 CY GRANULARFILTER & GEOTEXTILE PERDETAIL C5.1/4, SEE GRADINGPLAN FOR HOLD DOWNINSPECTION PORT, SEEDETAILRE=968.60±INSPECTION PORT, SEEDETAILRE=969.00±INSPECTION PORT, SEEDETAILRE=969.00±MECHANICAL TO DETERMINE FINAL ROOF STORMWATERDRAIN, WATER AND SANITARY SERVICE SIZES. COORD. W/MECHANICAL AND PLUMBING PLANS PRIOR TO SITE UTILITYINSTALLATION. NOTIFY ENGINEER.civilsitegroup.comCOPYRIGHT 2018 CIVIL SITE GROUP INC.cISSUE/SUBMITTAL SUMMARYDATEDESCRIPTIONMOMENTS OF CHANHASSEN1660 ARBORETUM BLVD, CHANHASSEN, MN 5531716258 KENYON AVE, LAKEVILLE, MN 55004TMSC OF CHANHASSEN LLCPROJECT............PROJECT NUMBER: 1722744263Matthew R. PavekLICENSE NO.DATEI HEREBY CERTIFY THAT THIS PLAN,SPECIFICATION, OR REPORT WASPREPARED BY ME OR UNDER MY DIRECTSUPERVISION AND THAT I AM A DULYLICENSED PROFESSIONAL ENGINEERUNDER THE LAWS OF THE STATE OFMINNESOTA.02/14/2001/22/20 WATERSHED SUBMITTAL02/04/20 SITE PLAN02/18/20 CITY/WATERSHED RESUBMITTAL03/05/20 WATERSHED RESUBMITTAL....01/06/20 CITY SUBMITTALDRAWN BY:RL, JSREVIEWED BY:PSPRELIMINARY:NOT FORCONSTRUCTIONREVISION SUMMARYDATEDESCRIPTIONC4.0UTILITY PLAN............GENERAL UTILITY NOTES:UTILITY LEGEND:CITY OF CHANHASSEN UTILITY NOTES:NKnow what'sR civilsitegroup.comCOPYRIGHT 2018 CIVIL SITE GROUP INC.cISSUE/SUBMITTAL SUMMARYDATEDESCRIPTIONMOMENTS OF CHANHASSEN1660 ARBORETUM BLVD, CHANHASSEN, MN 5531716258 KENYON AVE, LAKEVILLE, MN 55004TMSC OF CHANHASSEN LLCPROJECT............PROJECT NUMBER: 1722744263Matthew R. PavekLICENSE NO.DATEI HEREBY CERTIFY THAT THIS PLAN,SPECIFICATION, OR REPORT WASPREPARED BY ME OR UNDER MY DIRECTSUPERVISION AND THAT I AM A DULYLICENSED PROFESSIONAL ENGINEERUNDER THE LAWS OF THE STATE OFMINNESOTA.02/14/2001/22/20 WATERSHED SUBMITTAL02/04/20 SITE PLAN02/18/20 CITY/WATERSHED RESUBMITTAL03/05/20 WATERSHED RESUBMITTAL....01/06/20 CITY SUBMITTALDRAWN BY:RL, JSREVIEWED BY:PSPRELIMINARY:NOT FORCONSTRUCTIONREVISION SUMMARYDATEDESCRIPTIONC5.1CIVIL DETAILS............CLFLOWFLOWSANITARY SEWER MANHOLEN T S6CATCH BASIN/MANHOLE/RISERREMARKSCASTING SCHEDULECASTING SCHEDULEN T SSTORM CURB INLETR-30674-551-3STORM MANHOLER-1642BIO-FILTRATION BASIN (RAIN GARDEN - TYP.)N T STYPICAL SECTION VIEWCONSTRUCTION SEQUENCING1BIO-FILTRATION BASIN OCSN T S2DROP STRUCTUREN T S3UNDERGROUND TDA FIELD INFILTRATION BASINN T S7RIPRAP @ FLARED END SECTIONSUBGRADE SOILS(IN-SITU SAND)2136"GEOTEXTILE FABRIC: 4OZ.; NON-SILTING;EXTEND 24" BEYONDTOP OF EXCAVATIONGRADEPAVEMENT,SEE DETAIL &GEOTECH FORSECTIONKEY1. MIN. 18" COVER BELOW BITUMINOUS PAVEMENT SECTION.2. TIRE DERIVED AGGREGATE FIELD; 50% VOID SPACE FOLLOWING COMPACTION, SEE PLAN FOR DEPTH &FOOTPRINT3. COUPLE SOLID PVC TO PERFORATED PVC FOR WATER LEVEL OBSERVATION.TYP. SECTION DETAILNTSCONSTRUCTION SEQUENCINGCB OR MANHOLE, SEE PLANINLET OR OUTLET PIPE, SEE PLAN FORINVERT, LENGTH AND SLOPE1:1 TRENCH SIDESLOPECRUSHED/SCREENEDCONCRETE BEDDING;2-4"; OR APPROVEDEQUAL; FILL TO PIPE,HAUNCH AND COMPACT6" PVC INSPECTION PIPE3TOP CASTINGFORINSPECTIONPORT4 civilsitegroup.comCOPYRIGHT 2018 CIVIL SITE GROUP INC.cISSUE/SUBMITTAL SUMMARYDATEDESCRIPTIONMOMENTS OF CHANHASSEN1660 ARBORETUM BLVD, CHANHASSEN, MN 5531716258 KENYON AVE, LAKEVILLE, MN 55004TMSC OF CHANHASSEN LLCPROJECT............PROJECT NUMBER: 1722744263Matthew R. PavekLICENSE NO.DATEI HEREBY CERTIFY THAT THIS PLAN,SPECIFICATION, OR REPORT WASPREPARED BY ME OR UNDER MY DIRECTSUPERVISION AND THAT I AM A DULYLICENSED PROFESSIONAL ENGINEERUNDER THE LAWS OF THE STATE OFMINNESOTA.02/14/2001/22/20 WATERSHED SUBMITTAL02/04/20 SITE PLAN02/18/20 CITY/WATERSHED RESUBMITTAL03/05/20 WATERSHED RESUBMITTAL....01/06/20 CITY SUBMITTALDRAWN BY:RL, JSREVIEWED BY:PSPRELIMINARY:NOT FORCONSTRUCTIONREVISION SUMMARYDATEDESCRIPTIONC5.3CIVIL DETAILS............ General Permit Number 2015-1192 MINNESOTA DEPARTMENT OF NATURAL RESOURCES Public Waters Work General Permit Expiration Date: 05/20/2020 Pursuant to Minnesota Statutes, Chapter 103G, and on the basis of statements and information contained in the permit application, letters, maps, and plans submitted by the applicant and other supporting data, all of which are made part hereof by reference, PERMISSION IS HEREBY GRANTED to the applicant to perform actions as authorized below. Resource:Watershed:County:Project Name: Riley-Purgatory-Bluff Creek Watershed District Hennepin and Carver Lower Minnesota River - Shakopee All Public Waters within Riley-Purgatory-Bluff Creek Watershed Authorized Action:Purpose of Permit: Sediment Removal, Sand Blanket w/o Excavation, Sand Blanket w/ Excavation, Riprap (Natural Rock), Retaining Wall, Erosion Control/Stabilization Fill & Grading, Culvert Construction/Modification/Replacement, Bridge Construction/Modification/Replacement, Bioengineering Place natural rock riprap; shape banks/shorelines for placement of riprap or bioengineering; install beach sand blankets; construct retaining walls, bridges and culverts; remove structures; remove sediment; all in accordance with the Conditions of this permit. N/ARiparian Property Owners within Riley-Purgatory-Bluff Creek Watershed District Permittee:Authorized Agent: Property Description (land owned or leased or where work will be conducted): Water Regulations Unit Supervisor Tom Hovey Expiration Date:Effective Date:Issued Date:Title:Authorized Issuer: 05/20/202009/22/201509/22/2015 This permit is granted subject to the following CONDITIONS: APPLICABLE FEDERAL, STATE, OR LOCAL REGULATIONS: The permittee is not released from any rules, regulations, requirements, or standards of any applicable federal, state, or local agencies; including, but not limited to, the U.S. Army Corps of Engineers, Board of Water and Soil Resources, MN Pollution Control Agency, watershed districts, water management organizations, county, city and township zoning. NOT ASSIGNABLE: This permit is not assignable by the permittee except with the written consent of the Commissioner of Natural Resources. NO CHANGES: The permittee shall make no changes, without written permission or amendment previously obtained from the Riley-Purgatory-Bluff Creek Watershed District or the Commissioner of Natural Resources, in the dimensions, capacity or location of any items of work authorized hereunder. SITE ACCESS: The permittee shall grant access to the site at all reasonable times during and after construction to authorized representatives of the Commissioner of Natural Resources for inspection of the work authorized hereunder. TERMINATION: This permit may be terminated by the Commissioner of Natural Resources at any time deemed necessary for the conservation of water resources of the state, or in the interest of public health and welfare, or for violation of any of the conditions or applicable laws, unless otherwise provided in the permit. CONDITIONS continued on next page...(MPARS revision 10/07/2013, Permit Issuance ID 14270, printed 09/22/2015) GENERAL PERMIT CONDITIONS (Continued from previous page) COMPLETION DATE: Construction work authorized under this permit shall be completed on or before the date specified above. The permittee may request an extension of the time to complete the project by submitting a written request, stating the reason thereof, to the Commissioner of Natural Resources. WRITTEN CONSENT: In all cases where the permittee by performing the work authorized by this permit shall involve the taking, using, or damaging of any property rights or interests of any other person or persons, or of any publicly owned lands or improvements thereon or interests therein, the permittee, before proceeding, shall obtain the written consent of all persons, agencies, or authorities concerned, and shall acquire all property, rights, and interests needed for the work. PERMISSIVE ONLY / NO LIABILITY: This permit is permissive only. No liability shall be imposed by the State of Minnesota or any of its officers, agents or employees, officially or personally, on account of the granting hereof or on account of any damage to any person or property resulting from any act or omission of the permittee or any of its agents, employees, or contractors. This permit shall not be construed as estopping or limiting any legal claims or right of action of any person other than the state against the permittee, its agents, employees, or contractors, for any damage or injury resulting from any such act or omission, or as estopping or limiting any legal claim or right of action of the state against the permittee, its agents, employees, or contractors for violation of or failure to comply with the permit or applicable conditions. EXTENSION OF PUBLIC WATERS: Any extension of the surface of public waters from work authorized by this permit shall become public waters and left open and unobstructed for use by the public. WETLAND CONSERVATION ACT: Where the work authorized by this permit involves the draining or filling of wetlands not subject to DNR regulations, the permittee shall not initiate any work under this permit until the permittee has obtained official approval from the responsible local government unit as required by the Minnesota Wetland Conservation Act. INVASIVE SPECIES - EQUIPMENT DECONTAMINATION: All equipment intended for use at a project site must be free of prohibited invasive species and aquatic plants prior to being transported into or within the state and placed into state waters. All equipment used in designated infested waters, shall be inspected by the Permittee or their authorized agent and adequately decontaminated prior to being transported from the worksite. The DNR is available to train inspectors and/or assist in these inspections. For more information refer to the "Best Practices for Preventing the Spread of Aquatic Invasive Species" at http://files.dnr.state.mn.us/publications/ewr/invasives/ais/best_practices_for_prevention_ais.pdf. Contact your regional Invasive Species Specialist for assistance at www.mndnr.gov/invasives/contacts.html. A list of designated infested waters is available at www.mndnr.gov/invasives/ais/infested.html. A list of prohibited invasive species is available at www.mndnr.gov/eco/invasives/laws.html#prohibited. CONSTRUCTION DEWATERING - GENERAL: All construction dewatering in excess of 10,000 gallons per day or one million gallons per year must be authorized by a separate water appropriation permit. All worksite discharge water must be treated for sediment reduction prior to return to the surface water. Water from designated infested waters shall not be diverted to other waters, transported on a public road, or transported or appropriated off property riparian to infested waters without a DNR permit specifically for this use. All equipment in contact with infested waters must be decontaminated upon leaving the site. EROSION AND SEDIMENT CONTROL: In all cases, methods that have been determined to be the most effective and practical means of preventing or reducing sediment from leaving the worksite shall be installed in areas that slope to the water and on worksite areas that have the potential for direct discharge due to pumping or draining of areas from within the worksite (e.g., coffer dams, temporary ponds, stormwater inlets). These methods, such as mulches, erosion control blankets, temporary coverings, silt fence, silt curtains or barriers, vegetation preservation, redundant methods, isolation of flow, or other engineering practices, shall be installed concurrently or within 24 hours after the start of the project, and will be maintained for the duration of the project in order to prevent sediment from leaving the worksite. DNR requirements may be waived in writing by the authorized DNR staff based on site conditions, expected weather conditions, or project completion timelines. EXCAVATED MATERIALS - FLOODPLAIN CONCERN: Excavated material shall not be permanently placed within community designated floodplain areas or shoreland areas, unless all necessary local permits and approvals have been obtained. CONDITIONS continued on next page...Page 2 - General Permit Number 2015-1192 GENERAL PERMIT CONDITIONS (Continued from previous page) AQUATIC PLANT MANAGEMENT: For projects where vegetation is placed waterward of the ordinary high water level, a separate Aquatic Plant Management (APM) permit is needed from the DNR Area Fisheries Manager. See contact list at: http://files.dnr.state.mn.us/fisheries/management/dnr_fisheries_managers.pdf. A permit shall be obtained (no fee required) for each site in order to monitor plant source, species, and planting location. Vegetation must be appropriate for the site and free of invasive species. This condition does not apply when only woody vegetation is used, such as willow and dogwood. APPLICABLE PROJECTS: A project not meeting applicable conditions of this permit or a project the DNR identifies as having the potential for significant resource impacts, is not authorized herein. Rather, such projects will require an individual DNR permit application. ENVIRONMENTAL REVIEW: If the project proposal is part of a project that requires mandatory environmental review pursuant to MN Environmental Quality Board rules, then the permit is not valid until environmental review is completed. RETAINING WALLS: Retaining walls are generally discouraged because their impact on the near-shore aquatic environment can be severe and they restrict wildlife movement, however, they may be permitted if the following conditions are met: a. Existing or expected erosion problems shall preclude the use of riprap shore protection with a finished slope of 2:1 (horizontal to vertical) or more gentle, due to steep banks, nearby structures or other extenuating circumstances; or there shall be a demonstrated need for direct shoreland docking. b. Design shall be consistent with existing uses in the area. Examples are: riverfront commercial-industrial areas having existing structures of this nature, dense residential areas where similar retaining walls are common, or where barges are utilized to carry equipment and supplies. c. Adequate engineering studies shall be performed on foundation conditions, tiebacks, internal drainage, construction materials, and protection against flanking. d. The facility shall not be an aesthetic intrusion upon the area and is consistent with all applicable local, state, and federal management plans and programs for the water body. e. Encroachment below the ordinary high water elevation shall be limited to the absolute minimum necessary for construction. ICE RIDGE REMOVAL: Ice ridge removal projects must meet the DNR "no permit required" conditions for ice ridge removal specified in Minn. Rules part 6115.0215, Subpart 4. If not, a DNR Individual permit is required as District rules do not address this category of project. HYDROLOGIC / HYDRAULIC DATA REPORTING :: Unless waived by the DNR Area Hydrologist, hydrologic modeling to show the impacts of a bridge or culvert constructed in a Public Water to the 100-year flood elevation is required . Additional modeling may also be required for temporary fill or temporary structures required during demolition or construction. Calculations showing calculated velocities through the structures at 2-year peak flows may also be required. FISHERY PROTECTION - EXCLUSION DATES: No activity affecting the bed of the protected water may be conducted between March 15 and April 15 on watercourses, or between April 1 and June 30 on all other waterbodies, to minimize impacts on fish spawning and migration. If work during this time is essential, it shall be done only upon written approval of the Area Fisheries Manager. See contact list at: http://files.dnr.state.mn.us/fisheries/management/dnr_fisheries_managers.pdf Should work begin elsewhere in the project area within these dates, all exposed soils that are within 200 feet of Public Waters and drain to those waters must complete erosion control measures within 24 hours of its disturbance to prevent sediment from entering Public Waters. REPORTING: The Riley-Purgatory-Bluff Creek Watershed District shall submit annually or as requested a summary report of the projects authorized under this General Permit to the Area Hydrologist. CONSTRUCTION AIDS: No construction is allowed of temporary channel diversions or placement of fill for temporary work pads, bypass roads, access roads, or coffer dams to aid in the construction of any authorized structure unless approved in writing by the Area Hydrologist prior to beginning work . FISH PASSAGE: Bridges, culverts and other crossings shall provide for fish movement unless the structure is intended to impede rough fish movement or the stream has negligible fisheries value as determined by the DNR Area Hydrologist in consultation with the Area Fisheries Manager. The accepted practices for achieving these conditions include: Where possible a single culvert or bridge shall span the natural bankfull width adequate to allow for debris and sediment transport rates to closely resemble those of upstream and downstream conditions. A single culvert shall be recessed in order to pass bedload and sediment load. Additional culvert inverts should be set at a higher elevation. All culverts should match the alignment and slope of the natural stream channel, and extend through the toe of the road side slope. "Where possible" means that other conditions may exist and could take precedence, such as unsuitable substrate, natural slope and background velocities, bedrock, flood control, 100 year flood elevations, wetland/lake level control elevations, local CONDITIONS continued on next page...Page 3 - General Permit Number 2015-1192 GENERAL PERMIT CONDITIONS (Continued from previous page) ditch elevations, and other adjacent features. Rock Rapids or other structures may be used to retrofit crossings to mimic natural conditions. PHOTOS AND AS-BUILTS: Upon completion of the authorized work, the permittee may be required to submit a copy of established benchmarks, representative photographs, and may be required to provide as-built surveys of Public Watercourse crossing changes. EXCAVATION OF PUBLIC WATERS: Excavation of Public Waters is authorized by this permit only when the proposed excavation is consistent with Minnesota Rules 6115.0200 and 6115.0201. REMOVAL OF STRUCTURES: Removal of structures from public waters is authorized by this permit when the proposed removal is consistent with Minnesota Rules 6115.0211 subp. 8. Jeanne Daniels, EWR District Managercc: Page 4 - General Permit Number 2015-1192