Recommended Wetland Management Standards According to Management Class

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3 Recommended Wetland Management Standards According to Management Class Measure Management Strategy Management Class Preserve Manage 1 Manage 2 Manage 3 Maintain wetland and existing functions, values and wildlife habitat. Possible need for active management of wetland to protect unique features. Apply strict avoidance standards. Maintain wetland without degrading existing functions, values and wildlife habitat. Maintain wetland footprint. Improve wetland biological and plant community diversity/integrity or enhance other functions if possible. 5 Consider rehabilitating one or more functions. 6 Bounce (10-year) Existing Existing plus 0.5 feet Existing plus 1 feet No limit Inundation Period 1 (1&2 year) Inundation Period 1 (10-year) Existing Existing plus 1 day Existing plus 2 days Existing plus 7 days Existing Existing plus 7 days Existing plus 14 days Existing plus 21 days Runout Control 2 Stormwater Treatment No change, maintain existing hydrology Upstream sediment and nutrient pretreatment required to maintain (and, if possible, exceed) background loading rates No change, maintain existing hydrology Upstream sediment and nutrient pretreatment required to maintain (and, if possible, exceed) background loading rates 0 to 1 feet above existing outlet Remove sediment from new inflows Buffer Width ft ft ft. 25 ft. 0 to 4 feet above existing runout Remove sediment from new inflows 1 Inundation period is defined as the proposed peak storage divided by the average discharge (S/Q). 2 If currently landlocked, new outlet should be above delineated wetland elevation. 3 Buffers are unmowed, naturalized strips of vegetation around the perimeter of the wetland. While a general default number for a wildlife buffer is of limited value in and of itself, it is a reasonable starting point for general consideration/planning purposes pending more detailed site investigation. 4 Includes wetlands where vegetative diversity and wildlife habitat are a priority, identified by the Preserve row in Figures 10a and b (excluding Fish Habitat and Shoreline Protection); otherwise 100 ft. minimum for water quality protection. Based on Semlitsch and Bodie 2003, and SEWRPC Managing the Water s Edge Making Natural Connections. 5 Enhancement involves heightening, intensifying, or improving a single, specific function of an existing wetland, potentially to the detriment of other functions. 6 Rehabilitation involves repairing or increasing the functionality of an existing degraded wetland. Source: State of Minnesota Storm-Water Advisory Group Storm-Water and Wetlands: Planning and Evaluation Guidelines for Addressing Potential Impacts of Urban Storm-Water and Snow-Melt Runoff on Wetland, as modified in Minnesota Board of Soil and Water Resources Recommended Wetland Management Classification System to Accompany the Minnesota Routine Assessment Method for Evaluating Wetland Functions, (MnRAM) Version 3.4,.Draft.

4 Susceptibility of Wetlands to Degradation by Stormwater Impacts Exceptionally Susceptible Wetland Types: 1 Highly Susceptible Wetland Types: 2 Moderately Susceptible Wetland Types: 3 Least Susceptible Wetland Types: 4 Sedge Meadows Shrub-carrs a Floodplain Forests a Gravel Pits b Fresh (Wet) Open Bogs Alder Thickets Meadows b Cultivated Hydric Soils Coniferous Bogs Fresh (Wet) Meadows c,e Shallow Marshes c Material Disposal Dredged Material/Fill Sites Calcareous Fens Shallow Marshes d,e Deep Marshes c Low Prairies Deep Marshes d,e Lowland Hardwood Swamps Seasonally Flooded Wetlands Notes: Special consideration must be given to avoid altering these wetland types. Inundation must be avoided. Water chemistry changes due to alteration by stormwater impacts can also cause adverse impacts. Note: All scientific and natural areas and pristine wetland should be considered in this category regardless of wetland type. a., b., c. Can tolerate inundation from 6 inches to 12 inches for short periods of time. May be completely dry in drought or late summer conditions. d. Can tolerate +12 inches inundation, but adversely impacted by sediment and/or nutrient loading and prolonged high water levels. e. Some exceptions. a. Can tolerate annual inundation of 1 to 6 feet or more, possibly more than once/year. b. Fresh meadows that are dominated by reed canary grass. c. Shallow marshes dominated by reed canary grass, cattail, giant reed, or purple loosestrife. These wetlands are usually so degraded that input of urban storm water may not have adverse impacts. There will always be exceptions to the general categories listed above. Use best professional judgment. A more complete description of wetland characteristics under each category is contained in Attachment A of the source (see footnote). Pristine wetlands are those that show little disturbance from human activity.

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7 Recommended Wetland Management Standards According to Management Class Measure Management Strategy Management Class Preserve Manage 1 Manage 2 Manage 3 Maintain wetland and existing functions, values and wildlife habitat. Possible need for active management of wetland to protect unique features. Apply strict avoidance standards. Maintain wetland without degrading existing functions, values and wildlife habitat. Maintain wetland footprint. Improve wetland biological and plant community diversity/integrity or enhance other functions if possible. 5 Consider rehabilitating one or more functions. 6 Bounce (10-year) Existing Existing plus 0.5 feet Existing plus 1 feet No limit Inundation Period 1 (1&2 year) Inundation Period 1 (10-year) Existing Existing plus 1 day Existing plus 2 days Existing plus 7 days Existing Existing plus 7 days Existing plus 14 days Existing plus 21 days Runout Control 2 Stormwater Treatment No change, maintain existing hydrology Upstream sediment and nutrient pretreatment required to maintain (and, if possible, exceed) background loading rates No change, maintain existing hydrology Upstream sediment and nutrient pretreatment required to maintain (and, if possible, exceed) background loading rates 0 to 1 feet above existing outlet Remove sediment from new inflows Buffer Width ft ft ft. 25 ft. 0 to 4 feet above existing runout Remove sediment from new inflows 1 Inundation period is defined as the proposed peak storage divided by the average discharge (S/Q). 2 If currently landlocked, new outlet should be above delineated wetland elevation. 3 Buffers are unmowed, naturalized strips of vegetation around the perimeter of the wetland. While a general default number for a wildlife buffer is of limited value in and of itself, it is a reasonable starting point for general consideration/planning purposes pending more detailed site investigation. 4 Includes wetlands where vegetative diversity and wildlife habitat are a priority, identified by the Preserve row in Figures 10a and b (excluding Fish Habitat and Shoreline Protection); otherwise 100 ft. minimum for water quality protection. Based on Semlitsch and Bodie 2003, and SEWRPC Managing the Water s Edge Making Natural Connections. 5 Enhancement involves heightening, intensifying, or improving a single, specific function of an existing wetland, potentially to the detriment of other functions. 6 Rehabilitation involves repairing or increasing the functionality of an existing degraded wetland. Source: State of Minnesota Storm-Water Advisory Group Storm-Water and Wetlands: Planning and Evaluation Guidelines for Addressing Potential Impacts of Urban Storm-Water and Snow-Melt Runoff on Wetland, as modified in Minnesota Board of Soil and Water Resources Recommended Wetland Management Classification System to Accompany the Minnesota Routine Assessment Method for Evaluating Wetland Functions, (MnRAM) Version 3.4,.Draft.

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9 Zones of Protection for Semi-Aquatic Species Source: Semlitsch, R and R. Bodie Biological Criteria for Buffer Zones around Wetlands and Riparian Habitats for Amphibians and Reptiles. Conservation Biology 17 (5).

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12 Wetland Management Recommendations According to Management Class Measure Management Strategy Management Class Preserve Manage 1 Manage 2 Manage 3 Maintain wetland and existing functions, values and wildlife habitat. Possible need for active management of wetland to protect unique features. Apply strict avoidance standards. Maintain wetland without degrading existing functions, values and wildlife habitat. Maintain wetland footprint. Improve wetland biological and plant community diversity/integrity or enhance other functions if possible. 5 Consider rehabilitating one or more functions. 6 Bounce (10-year) Existing Existing plus 0.5 feet Existing plus 1 feet No limit Inundation Period 1 (1&2 year) Inundation Period 1 (10-year) Existing Existing plus 1 day Existing plus 2 days Existing plus 7 days Existing Existing plus 7 days Existing plus 14 days Existing plus 21 days Runout Control 2 Stormwater Treatment No change, maintain existing hydrology Upstream sediment and nutrient pretreatment required to maintain (and, if possible, exceed) background loading rates No change, maintain existing hydrology Upstream sediment and nutrient pretreatment required to maintain (and, if possible, exceed) background loading rates 0 to 1 feet above existing outlet Remove sediment from new inflows Buffer Width 3,4 700 ft 700 ft. 400 ft. 100 ft. 0 to 4 feet above existing runout Remove sediment from new inflows 1 Inundation period is defined as the proposed peak storage divided by the average discharge (S/Q). 2 If currently landlocked, new outlet should be above delineated wetland elevation. 3 Buffers are unmowed, naturalized strips of vegetation around the perimeter of the wetland. While a general default number for a wildlife buffer is of limited value in and of itself, it is a reasonable starting point for general consideration/planning purposes pending more detailed site investigation. 4 Includes wetlands where vegetative diversity and wildlife habitat are a priority, identified by the Preserve row in Figures 10a and b (excluding Fish Habitat and Shoreline Protection); otherwise 100 ft. minimum for water quality protection. Based on Semlitsch and Bodie 2003, and SEWRPC Managing the Water s Edge Making Natural Connections. 5 Enhancement involves heightening, intensifying, or improving a single, specific function of an existing wetland, potentially to the detriment of other functions. 6 Rehabilitation involves repairing or increasing the functionality of an existing degraded wetland. Source: State of Minnesota Storm-Water Advisory Group Storm-Water and Wetlands: Planning and Evaluation Guidelines for Addressing Potential Impacts of Urban Storm-Water and Snow-Melt Runoff on Wetland, as modified in Minnesota Board of Soil and Water Resources Recommended Wetland Management Classification System to Accompany the Minnesota Routine Assessment Method for Evaluating Wetland Functions, (MnRAM) Version 3.4,.Draft.

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