Difference between revisions of "Infiltration design guideline - landscaping"
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{{alert|It is ''REQUIRED'' that impervious area construction is completed and pervious areas established with dense and healthy vegetation prior to introduction of stormwater into a vegetated infiltration practice.|alert-danger}} | {{alert|It is ''REQUIRED'' that impervious area construction is completed and pervious areas established with dense and healthy vegetation prior to introduction of stormwater into a vegetated infiltration practice.|alert-danger}} | ||
| − | Landscaping is critical to the performance and function of vegetated areas of infiltration practices. Therefore, a landscaping plan is ''HIGHLY RECOMMENDED'' for vegetated infiltration practices. ''RECOMMENDED'' planting guidelines for vegetated practices are as follows | + | Landscaping is critical to the performance and function of vegetated areas of infiltration practices. Therefore, a landscaping plan is ''HIGHLY RECOMMENDED'' for vegetated infiltration practices. ''RECOMMENDED'' planting guidelines for vegetated practices are as follows. |
| − | * Vegetation should be selected based on a specified zone of hydric tolerance. [http://www.pca.state.mn.us/index.php/water/water-types-and-programs/stormwater/stormwater-management/plants-for-stormwater-design.html ''Plants for Stormwater Design - Species selection for the Upper Midwest''] is a good resource. | + | *Vegetation should be selected based on a specified zone of <span title="An environment or habitat containing plenty of moisture; very wet"> '''hydric'''</span> tolerance. [http://www.pca.state.mn.us/index.php/water/water-types-and-programs/stormwater/stormwater-management/plants-for-stormwater-design.html ''Plants for Stormwater Design - Species selection for the Upper Midwest''] is a good resource. |
| − | * Native [[Minnesota plant lists|plant species]] should be specified over non-native species. Hardy native species that thrive in our ecosystem without chemical fertilizers and pesticides are the best choices. | + | *Native [[Minnesota plant lists|plant species]] should be specified over non-native species. Hardy <span title="A species that has been observed in the form of a naturally occurring and self-sustaining population in historical times. Non-natives do not meet this definition."> '''native species'''</span> that thrive in our ecosystem without chemical fertilizers and pesticides are the best choices. |
| − | * Many vegetated practices feature wild flowers and grasses as well as shrubs and some trees. | + | *Many vegetated practices feature wild flowers and grasses as well as shrubs and some trees. |
| − | * If woody vegetation is placed near inflow locations, it should be kept out of pretreatment devices and be far enough away to not hamper maintenance of pretreatment devices. | + | *If woody vegetation is placed near inflow locations, it should be kept out of <span title="Pretreatment reduces maintenance and prolongs the lifespan of structural stormwater BMPs by removing trash, debris, organic materials, coarse sediments, and associated pollutants prior to entering structural stormwater BMPs. Implementing pretreatment devices also improves aesthetics by capturing debris in focused or hidden areas. Pretreatment practices include settling devices, screens, and pretreatment vegetated filter strips."> [https://stormwater.pca.state.mn.us/index.php?title=Pretreatment '''pretreatment''']</span> devices and be far enough away to not hamper maintenance of pretreatment devices. |
| − | *Trees should not be planted directly overtop of | + | *Trees should not be planted directly overtop of <span title="An underground drain or trench with openings through which the water may percolate from the soil or ground above"> '''underdrain'''</span> and may be best located along the perimeter of the practice. |
| − | *[[Minnesota plant lists#Salt polerance|Salt resistant vegetation]] should be used in locations with probable adjacent salt application, | + | *[[Minnesota plant lists#Salt polerance|Salt resistant vegetation]] should be used in locations with probable adjacent salt application, e.g. roadside, parking lot, etc. |
| − | *Plugs, bare root plants or potted plants are RECOMMENDED over seed for herbaceous plants, shrubs, and trees. Erosion control mats pre-vegetated with herbaceous plants are also acceptable. For turf, sod is recommended over seed. (NOTE: Fluctuating water levels following seeding (prior to germination) can cause seed to float and be transported, resulting in bare areas that are more prone to erosion and weed invasion than vegetated areas. Seed is also difficult to establish through mulch, a common surface component of vegetated practices. It may take more than two growing seasons to establish the function and desired aesthetic of mature vegetation via seeding.) | + | *<span title="Small-sized seedlings grown in trays from expanded polystyrene or polythene filled usually with a peat or compost substrate."> '''Plugs'''</span>, bare root plants or potted plants are RECOMMENDED over seed for herbaceous plants, shrubs, and trees. [https://stormwater.pca.state.mn.us/index.php?title=Erosion_prevention_practices Erosion control mats] pre-vegetated with <span title="A plant whose growth dies down annually but whose roots or other underground parts survive"> '''herbaceous perennial'''</span> plants are also acceptable. For turf, sod is recommended over seed. (NOTE: Fluctuating water levels following seeding (prior to germination) can cause seed to float and be transported, resulting in bare areas that are more prone to erosion and weed invasion than vegetated areas. Seed is also difficult to establish through <span title="Mulch products are intended to reduce raindrop (splash) erosion, decrease sheet erosion, promote rain/snowmelt infiltration, increase soil moisture retention, regulate soil temperature, and in most cases, improve soil texture and increase organic matter. Mulch products include natural materials such as straw and other grasses, coconut fiber, and bark."> [https://stormwater.pca.state.mn.us/index.php?title=Erosion_prevention_practices_-_natural_and_synthetic_mulches '''mulch''']</span>, a common surface component of vegetated practices. It may take more than two growing seasons to establish the function and desired aesthetic of mature vegetation via seeding.) |
| − | *Vegetated practices should be operated | + | *Vegetated practices should be operated <span title="A stormwater system in which part or all of the stormwater runoff is diverted from the primary treatment practice. Partial diversion is employed for bypass runoff, which is runoff in excess of the designed treatment volume of the practice. Full offline diversion is employed as a temporary means to divert all runoff from a stormwater practice, typically to avoid erosion of exposed soil or establishment of vegetation."> '''offline'''</span> for 1 year or, within the first year, until vegetation is established. |
*Example target plant coverage includes | *Example target plant coverage includes | ||
**at least 50 percent of specified vegetation cover at end of the first growing season; | **at least 50 percent of specified vegetation cover at end of the first growing season; | ||
Revision as of 18:47, 6 June 2022
Warning: It is REQUIRED that impervious area construction is completed and pervious areas established with dense and healthy vegetation prior to introduction of stormwater into a vegetated infiltration practice.
Landscaping is critical to the performance and function of vegetated areas of infiltration practices. Therefore, a landscaping plan is HIGHLY RECOMMENDED for vegetated infiltration practices. RECOMMENDED planting guidelines for vegetated practices are as follows.
- Vegetation should be selected based on a specified zone of hydric tolerance. Plants for Stormwater Design - Species selection for the Upper Midwest is a good resource.
- Native plant species should be specified over non-native species. Hardy native species that thrive in our ecosystem without chemical fertilizers and pesticides are the best choices.
- Many vegetated practices feature wild flowers and grasses as well as shrubs and some trees.
- If woody vegetation is placed near inflow locations, it should be kept out of pretreatment devices and be far enough away to not hamper maintenance of pretreatment devices.
- Trees should not be planted directly overtop of underdrain and may be best located along the perimeter of the practice.
- Salt resistant vegetation should be used in locations with probable adjacent salt application, e.g. roadside, parking lot, etc.
- Plugs, bare root plants or potted plants are RECOMMENDED over seed for herbaceous plants, shrubs, and trees. Erosion control mats pre-vegetated with herbaceous perennial plants are also acceptable. For turf, sod is recommended over seed. (NOTE: Fluctuating water levels following seeding (prior to germination) can cause seed to float and be transported, resulting in bare areas that are more prone to erosion and weed invasion than vegetated areas. Seed is also difficult to establish through mulch, a common surface component of vegetated practices. It may take more than two growing seasons to establish the function and desired aesthetic of mature vegetation via seeding.)
- Vegetated practices should be operated offline for 1 year or, within the first year, until vegetation is established.
- Example target plant coverage includes
- at least 50 percent of specified vegetation cover at end of the first growing season;
- at least 90 percent of specified vegetation cover at end of the third growing season;
- supplement plantings to meet project specifications if cover targets are not met; and
- tailoring percent coverage targets to project goals and vegetation. For example, percent cover required for turf after 1 growing season would likely be 100 percent, whereas it would likely be lower for other vegetation types.
- Vegetated areas should be integrated into the site planning process, and aesthetic considerations should be taken into account in their siting and design.
Operation and maintenance of vegetated practices is critical to meeting these landscape recommendations and targets. For more information on operation and maintenance, see the section on operation and maintenance of stormwater infiltration practices.