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8. Avienda Chanhassen Sequencing Flexibility Memo 11-20-2017 KES 26105 Wild Rose Lane, Shorewood, Minnesota 55331, Phone: 952-401-8757, Fax: 952-401-8798 Memorandum Date: November 20, 2017 To: Andi Moffatt, WCA Agent for City of Chanhassen Cc: Mark Nordland, Level 7 Development Peder Larson, Larkin Hoffman Darren Lazan & Steve Sabraski, Landform Professional Services From: Melissa Barrett, Kjolhaug Environmental Services Company Re: Avienda Village, Chanhassen, MN WETLAND PERMIT APPLICATION SEQUENCING FLEXIBILITY REQUEST This memo and attached supporting information are provided to document that wetlands proposed for impact with the Avienda Village project meet MN WCA Rule 8420.0520 Sequencing. Subpt. 7a. Sequencing Flexibility. Sequencing flexibility offers a process for approving proposed wetland impacts when “the proposed replacement wetland is certain to provide equal or greater public value as determined based on a functional assessment reviewed by the technical evaluation panel using a methodology approved by the board.” (Minnesota Rules Part 8420.0520, Subp. 7a.B). The Applicant is asking the LGU to implement sequencing flexibility on this project because two of the four sequencing flexibility criteria listed below apply to the proposed wetland impacts. WCA Rules state that the LGU may allow sequencing flexibility if: 1. the wetlands to be impacted has been degraded to the point where wetland replacement would result in a certain gain in function and public value; 2. avoidance of wetlands would result in severe degradation of the wetland's ability to function and provide public value, for example, because of surrounding land uses, and the wetland's ability to function and provide public value cannot reasonably be maintained through implementation of best management practices, land use controls, or other mechanisms; 3. the only feasible and prudent upland site available for the project or replacement has greater ecosystem function and public value than the wetlands. This may be appropriate only if the applicant: a. demonstrates impact minimization to the wetland; b. agrees to perpetually preserve the designated upland site; and c. completely replaces the impacted wetland's functions and public value; or 4. the wetland is a site where human health and safety is a factor. Items 1 and 3 above apply to all proposed wetland impacts because:  The MnRAM assessment summary included as Table 1 of this memo (with MnRAM output results included in Attachment A of this document) demonstrates the wetlands to be impacted are rated Low for vegetative diversity/integrity and generally Low or Moderate for all other important wetland functions. In contrast, the wetland banks to be used for wetland replacement are high functioning for a number of wetland functions and values, and have a higher overall final wetland Management Classification rating.  Additional discussion on the degraded and partially drained conditions of wetlands to be impacted was included in Section 4.2 of the submitted Wetland Permit Application.  The stormwater assessment summary included as Tables 2 and 3 of this memo (with output results compiled from the engineer’s most recent stormwater management plan dated November 20, 2017) demonstrates that existing site conditions do not currently meet water quality standards, and that proposed post-development conditions will result in an improvement to downstream water quality (specifically total phosphorus and total suspended solids), satisfaction of City non-degradation requirements, and improvements to water quality in the Lake Susan Watershed as identified by the Lake Susan UAA plan.  In addition to water quality improvements that will occur with development of the proposed project, the Applicant will provide funds to the City for other water improvement projects within the City and/or watershed for implementation at their discretion.  Approximately 20 acres of upland woodland located within the Bluff Creek Overlay District (BCOD) will be placed in a perpetual conservation easement. This upland has greater ecosystem function and public value than the wetlands proposed for impact. This woodland is a remnant of the North Central Hardwood Forest and currently contains little to no invasive species. Specifically, this woodland lacks common buckthorn, which is often present in remnant forest communities. This woodland contains bluff slopes, one Preserve quality wetland (Wetland 10, Appendix F of the Wetland Permit Application), and one documented cultural resource site.  Wetland impact minimization discussions have been included in previous submittals. Efforts have been made to avoid all wetland impacts where feasible. Wetlands 3, 4, and 10 have been avoided completely, and impacts to Wetland 6 have been minimized by 50%. With submission of this memo and attached supporting information, we are requesting that the LGU implement sequencing flexibility on this project. Thank you. Table 1. MnRAM Assessment Summary - Avienda Village, Chanhassen, MN1256789#1494; Drummer Bank (BSA9, Wtsh 32, Blue Earth Co)#1605; Schmidgall Bank (BSA9, Wtsh 23, Stevens Co)#174; Ryan Bank (BSA9, Wtsh 33, Rice Co)#1636; Kremer Bank 1 (BSA9, Wtsh 25, Lyon Co)Vegetative Diversity/Integrity Moderate Low Low Low Low Low Low High High Moderate HighMaintenance of Hydrologic RegimeLow Low Low Moderate Low Low Low Moderate Moderate High HighFlood/Stormwater/Attenuation Moderate Moderate Moderate Moderate Moderate Moderate Moderate High High Moderate HighDownstream Water Quality Moderate Moderate Moderate High Moderate Moderate Moderate Moderate Moderate Moderate ModerateMaintenance of Wetland Water QualityLow Low Low Moderate Low Low Low High High Moderate HighShoreline Protection NA NA NA NA NA NA NA NA NA NA NAWildlife Habitat Low Low Low Low Low Low Low High High High ModerateFish Habitat NA NA NA NA NA NA NA Moderate NA NA NAAmphibian Habitat Low Low NA NA NA NA NA Moderate Moderate Moderate ModerateAesthetic/Recreation/ Education/CulturalLow Low Low Moderate Low Low Low Moderate Moderate Exceptional ModerateFinal Management Classification 2Manage 2 Manage 2 Manage 3 Manage 2 Manage 3 Manage 3 Manage 3Preserve (Wetland Water Quality = High & Veg Diversity/Integrity = High)Preserve (Wetland Water Quality = High & Veg Diversity/Integrity = High)Preserve (Aesthetics etc. = Exceptional & Wildlife Habitat = High)Preserve (Wetland Hydrology = High & Veg Diversity/Integrity = High)1 Additional wetland bank that may be used in the event credit availability from other bank/s change.2 Preserve = Exceptional; Manage 1 = High Quality; Manage 2 = Medium Quality; Manage 3 = Low Quality Avienda Existing Wetlands (BSA9, Wtsh 33, Carver Co) Mitigation Wetland BanksWetlands & Wetland Functions/Values Table 2: Stormwater Assessment Summary Major Watershed Hydrologic – Runoff Volume per Storm (af)* Water Quality – TP (lbs./yr.) Water Quality – TSS (lbs./yr.)Lake Susan UAA Plan 1-yr: 2.594 10-yr: 7.500 100-yr: 16.854 1-yr: 5.268 10-yr: 14.064 100-yr: 32.729 1-yr: 3.500 10-yr: 9.201 100-yr: 19.443 1-yr: 5.616 10-yr: 15.983 100-yr: 35.469 Discharge to Lake Susan Increases in total runoff volume to Lake Susan of 115%-135%; Reduction of 3.06 lb.s/yr. in Lake Susan watershed Reduction of 1,439.8 lbs./yr in Lake Susan watershed Improvement to water quality in Lake Susan watershed Discharge to Bluff Creek Increases in total runoff volume to Bluff Creek of 107%-108% Reduction of 17.06 lbs./yr. in Bluff Creek watershed Reduction of 7,598.7 lbs/yr. in Bluff Creek watershed na Table 3: Non-Degredation Summary Major Watershed Non-Degredation Requirement per City, Annual Maximum Allowable Runoff (af) Non-Degredation per Site P8 Modeling, Annual Runoff (af) Results * Total runoff volumes per storm are not directly regulated City or Watershed rules. Refer to non-degradation summary for runoff volume compliance. 8,786.70 na Discharge to Lake Susan 10.57 1,943.40 No methods implemented/no change 1,188.00 na Discharge to Lake Susan 7.51 503.6 Helps to meet TP goal, reduces TP by 3.06 lbs./yr.Existing ConditionsProposed ConditionsResultsDischarge to Bluff Creek 21.59 Discharge to Bluff Creek 38.65 Proposed ConditionsDischarge to Lake Susan Discharge to Bluff Creek Satisfied Satisfied127.3 73.6 56.5 55.6 Avienda Village, Chanhassen, MN WETLAND PERMIT APPLICATION SEQUENCING FLEXIBILITY REQUEST ATTACHMENT A –MNRAM OUTPUT RESULTS Wetland Community Summary Avienda Cowardin ClassificationWetland Name Location Vegetative Diversity/Integrity Plant Community Circular 39 Wetland Proportion Individual Community Rating Highest Wetland Rating Average Wetland Rating Weighted Average Wetland Rating Community * PEMA Type 1 Fresh (Wet) Meadow 100 0.110-116-23-23-001Avienda WL3 Low Low Low100 PEMAd Type 1 Fresh (Wet) Meadow 100 0.110-116-23-23-001Avienda WL4 Low Low Low100 PEMAd Type 1 Fresh (Wet) Meadow 100 0.110-116-23-23-001Avienda WL6 Low Low Low100 PEMAd Type 1 Fresh (Wet) Meadow 100 0.110-116-23-23-001Avienda WL7/8 Low Low Low100 PFO1A Type 1 Seasonally Flooded Basin 100 0.510-116-23-23-001Avienda WL10 Moderate Moderate Moderate100 PEMF Type 4 Deep Marsh 60 0.510-116-23-23-001Avienda MnDOT WL PSS1B Type 6 Shrub Carr 20 0.5 PEM1A Type 1 Fresh (Wet) Meadow 20 0.5 Moderate Moderate Moderate100 PEMAd Type 1 Fresh (Wet) Meadow 80 0.110-116-23-23-001Avienda WL1 PEMCd Type 3 Shallow Marsh 20 0.5 Moderate Low Low100 PUBG Type 5 Shallow, Open Water Communities 0 0.110-116-23-23-001Avienda WL2 PEMBd Type 2 Fresh (Wet) Meadow 0 0.1 PEMAd Type 1 Fresh (Wet) Meadow 0 0.1 Friday, December 09, 2016 Page 1 of 2 * Denotes incomplete calculation data. Wetland Community Summary Avienda Cowardin ClassificationWetland Name Location Vegetative Diversity/Integrity Plant Community Circular 39 Wetland Proportion Individual Community Rating Highest Wetland Rating Average Wetland Rating Weighted Average Wetland Rating Community * Low Low Not Applicable PEMAd Type 1 Seasonally Flooded Basin 100 0.110-116-23-23-001Avienda WL5 Low Low Low100 PEMAd Type 1 Seasonally Flooded Basin 100 0.110-116-23-23-001Avienda WL9 Low Low Low100 Friday, December 09, 2016 Page 2 of 2 * Denotes incomplete calculation data. Wetland Name Maint. of Hydrologic Regime Flood/ Stormwater/ Attenuation Downstream Water Quality Maint. of Wetland Water Quality Shoreline Protection Wetland Functional Assessment Summary Avienda HydrogeomorphologyLocationWSSA Moderate High High Low Not ApplicableDepressional/Tributary (outlet but no perennial inlet or drainage entering from upstream subwatershed) Avienda WL3 10-116-23-23-001933 Low Moderate Moderate Low Not ApplicableDepressional/Flow-through (apparent inlet and outlet), Depressional/Flow-through (apparent inlet and outlet) Avienda WL4 10-116-23-23-001933 Moderate Moderate High Moderate Not ApplicableDepressional/Tributary (outlet but no perennial inlet or drainage entering from upstream subwatershed) Avienda WL6 10-116-23-23-001933 Low Moderate Moderate Low Not ApplicableDepressional/Tributary (outlet but no perennial inlet or drainage entering from upstream subwatershed) Avienda WL7/8 10-116-23-23-001933 High Moderate High High Not ApplicableDepressional/Isolated (no discernable inlets or outlets)Avienda WL10 10-116-23-23-001933 Moderate Moderate Moderate Moderate Not ApplicableDepressional/Tributary (outlet but no perennial inlet or drainage entering from upstream subwatershed) Avienda MnDOT WL 10-116-23-23-001933 Low Moderate Moderate Low Not ApplicableDepressional/Flow-through (apparent inlet and outlet), Depressional/Flow-through (apparent inlet and outlet) Avienda WL1 10-116-23-23-001933 Low Moderate Moderate Low Not ApplicableDepressional/Tributary (outlet but no perennial inlet or drainage entering from upstream subwatershed) Avienda WL2 10-116-23-23-001933 Low Moderate Moderate Low Not ApplicableDepressional/Tributary (outlet but no perennial inlet or drainage entering from upstream subwatershed) Avienda WL5 10-116-23-23-001933 Low Moderate Moderate Low Not ApplicableDepressional/Tributary (outlet but no perennial inlet or drainage entering from upstream subwatershed) Avienda WL9 10-116-23-23-001933 Friday, December 09, 2016 Page 1 of 1 Wetland Name Ground- Water Interaction Maint. of Char. of Wildlife Habitat Maint.of Char. Fish Habitat Aesthetics/ Recreation/ Education/ Cultural Commercial Uses Wetland Restoration Potential Additional Stormwater Treatment Needs Wetland Functional Assessment Summary Avienda Maint. of Char. Amphibian Habitat Additional Information Wetland Sensitivity to Stormwater and Urban Develop.Location RechargeModerateNot Applicable Moderate Not Applicable Not Applicable ModerateLowLowAvienda WL3 10-116-23-23-001 RechargeModerateNot Applicable Low Not Applicable Not Applicable ModerateLowModerateAvienda WL4 10-116-23-23-001 RechargeLowNot Applicable Moderate Not Applicable Not Applicable ModerateModerateNot ApplicabAvienda WL6 10-116-23-23-001 Combination Discharge, Recharge Low Not Applicable Low Not Applicable Not Applicable ModerateLowNot ApplicabAvienda WL7/8 10-116-23-23-001 RechargeHighNot Applicable Moderate Not Applicable Not Applicable ExceptionalHighHighAvienda WL10 10-116-23-23-001 Combination Discharge, Recharge Moderate Not Applicable Moderate Not Applicable Not Applicable ModerateModerateLowAvienda MnDOT WL 10-116-23-23-001 RechargeLowNot Applicable Low Not Applicable Not Applicable ModerateLowLowAvienda WL1 10-116-23-23-001 Combination Discharge, Recharge Low Not Applicable Low Not Applicable Not Applicable ModerateLowLowAvienda WL2 10-116-23-23-001 RechargeLowNot Applicable Low Low Moderate ExceptionalLowNot ApplicabAvienda WL5 10-116-23-23-001 RechargeLowNot Applicable Low Low Moderate ExceptionalLowNot ApplicabAvienda WL9 10-116-23-23-001 Friday, December 09, 2016 Page 1 of 1 MnRAM_3.2_Score_Sheet.xls Drummer Wetland Bank Function Name Vegetative Diversity/Integrity 1.00 High Hydrology - Characteristic 0.63 Med Flood Attenuation 0.68 High Water Quality--Downstream 0.58 Med Water Quality--Wetland 0.85 High Shoreline Protection N/A N/A Characteristic Wildlife Habitat Structure 0.69 0.69 High Maintenance of Characteristic Fish Habitat 0.60 0.60 Med Maintenance of Characteristic Amphibian Habitat 0.50 Med Aesthetics/Recreation/Education/Cultural 0.49 0.49 Med Commercial use N/A N/A 0 Special Features listing:p 0 Groundwater Interaction discharge Groundwater Functional Index no special indicators Restoration Potential (draft formula) N/A N/A Stormwater Sensitivity (not active)Final RatingRating CategoryFunctional Rating SummariesRaw score9608 MnRAM_Excel_Spreadsheet 1 11/16/2017 Wetland Functional Assessment SummaryWetland NameMaintenance of Hydrologic RegimeFlood/ Stormwater/ AttenuationDownstreamWaterQuality Maintenance of WetlandWaterQualityShorelineProtectionHydrogeomorphologyWetland NameGround-WaterInteractionMaintenance of Characteristic Wildlife Habitat StructureMaintenance of Characteristic Fish HabitatAesthetics/Recreation/Education/ CulturalCommercial UsesWetlandRestorationPotentialWetland Sensitivity to Stormwaterand Urban Development Additional StormwaterTreatmentNeedsMaintenance of Characteristic Amphibian HabitatAdditional InformationCowardinClassificationWetland Name LocationVegetative Diversity/IntegrityPlantCommunityWetland Community SummaryCircular39 WetlandProportionIndividualCommunityRatingHighestWetlandRatingAverageWetlandRatingWeightedAverageWetlandRatingCommunityDenotes incomplete calculation data.Moderate High Moderate High Not ApplicableDepressional/Tributary (outlet but no perennial inlet or drainage entering from upstream subwatershed)0.63 0.73 0.56 0.82 0.00Schmidgall BankCombination Discharge, RechargeHigh Not Applicable Moderate Not Applicable Not Applicable High HighModerate0.69 0.00 0.54 0.00 0.00 1.00 0.820.52Schmidgall BankPEM1FType 4Deep Marsh7511.000.830.95HighHighHighSchmidgall Bank 75-124-43-20-001PEM1CType 3Shallow Marsh1511.000.830.95HighHighHighPEM1AType 2Wet to Wet-Mesic Prairie100.51.000.830.95HighHighHighHighHighHigh1001.000.830.95Friday, November 17, 2017Page 1 of 1 Wetland Functional Assessment Summary Wetland Name Maintenance of Hydrologic Regime Flood/ Stormwater/ Attenuation Downstream Water Quality Maintenance of Wetland Water Quality Shoreline ProtectionHydrogeomorphology Wetland Name Ground- Water Interaction Maintenance of Characteristic Wildlife Habitat Structure Maintenance of Characteristic Fish Habitat Aesthetics/ Recreation/ Education/ Cultural Commercial Uses Wetland Restoration Potential Wetland Sensitivity to Stormwater and Urban Development Additional Stormwater Treatment Needs Maintenance of Characteristic Amphibian Habitat Additional Information Cowardin ClassificationWetland Name Location Vegetative Diversity/Integrity Plant Community Wetland Community Summary Circular 39 Wetland Proportion Individual Community Rating Highest Wetland Rating Average Wetland Rating Weighted Average Wetland Rating Community Denotes incomplete calculation data. High Moderate Moderate Moderate Not Applicable Depressional/Tributary (outlet but no perennial inlet or drainage entering from upstream subwatershed) 0.77 0.64 0.42 0.60 0.00Ryan Bank Combination Discharge, Recharge High Not Applicable Exceptional Not Applicable Not Applicable Moderate ModerateModerate 0.73 0.00 2.00 0.00 0.00 0.50 0.600.60Ryan Bank PUBG Type 5 Shallow, Open Water Communities 55 0.5 0.50 0.50 0.50 Moderate Moderate Moderate Ryan Bank 66-112-22-26-001 PEM1F Type 4 Deep Marsh 15 0.5 0.50 0.50 0.50 Moderate Moderate Moderate PEM1C Type 3 Shallow Marsh 15 0.5 0.50 0.50 0.50 Moderate Moderate Moderate PFO1B Type 1 Hardwood Swamp 15 0.5 0.50 0.50 0.50 Moderate Moderate Moderate Moderate Moderate Moderate1000.50 0.50 0.50 Monday, November 20, 2017 Page 1 of 2 Wetland Functional Assessment SummaryWetland NameMaintenance of Hydrologic RegimeFlood/ Stormwater/ AttenuationDownstreamWaterQuality Maintenance of WetlandWaterQualityShorelineProtectionHydrogeomorphologyWetland NameGround-WaterInteractionMaintenance of Characteristic Wildlife Habitat StructureMaintenance of Characteristic Fish HabitatAesthetics/Recreation/Education/ CulturalCommercial UsesWetlandRestorationPotentialWetland Sensitivity to Stormwaterand Urban Development Additional StormwaterTreatmentNeedsMaintenance of Characteristic Amphibian HabitatAdditional InformationCowardinClassificationWetland Name LocationVegetative Diversity/IntegrityPlantCommunityWetland Community SummaryCircular39 WetlandProportionIndividualCommunityRatingHighestWetlandRatingAverageWetlandRatingWeightedAverageWetlandRatingCommunityDenotes incomplete calculation data.High High Moderate High Not ApplicableDepressional/Tributary (outlet but no perennial inlet or drainage entering from upstream subwatershed)0.88 0.68 0.54 0.83 0.00Kremer BankCombination Discharge, RechargeModerate Not Applicable Moderate Not Applicable Not Applicable High HighModerate0.65 0.00 0.49 0.00 0.00 1.00 0.830.60Kremer BankPEM1CType 3Shallow Marsh500.51.000.830.75HighHighHighKremer Bank 42--00-00-001PEM1AType 1Wet to Wet-Mesic Prairie2511.000.830.75HighHighHighPEM1BType 2Fresh (Wet) Meadow2511.000.830.75HighHighHighHighHighHigh1001.000.830.75Friday, November 17, 2017Page 1 of 1