Holland City Zoning Code
ARTICLE 39
6 Landscaping and Green Infrastructure
Sec. 39-6.01 Intent.
[7-21-2021 by Ord. No. 1796]
A.
The intent of this article is to ensure the long-term environmental sustainability of the City of Holland by applying standards that preserve and enhance the City's tree and landscaping coverage and enable developments to meet low-impact development (LID) goals by incorporating green infrastructure into site design. LID assists the City in reaching its goals to decrease flooding events, erosion, and pollutants entering the waterways, and to protect groundwater and surface water quality by infiltrating, filtering, storing, and detaining stormwater runoff close to its source. These investments yield multiple benefits toward building City resilience, as indicated in detail below.
B.
Benefits of low-impact development (LID) standards.
1.
Preserve, protect, and enhance the City's urban tree canopy. One of the City's sustainability and resiliency goals is to preserve, protect, and enhance the City of Holland's urban tree canopy. This provides numerous natural benefits for air and water quality, prevents the urban heat island effect, reduces harmful UV radiation, lowers heating and cooling costs, mitigates soil erosion and stream pollution, and ensures long-term environmental sustainability, since planting trees remains one of the cheapest and most effective means of drawing excess CO2 from the atmosphere.
 |
2.
Promote surface infiltration. LID is achieved through site design that promotes surface water infiltration when impervious surfaces (buildings, parking lots, etc.) are clustered to preserve undeveloped, landscaped, or tree-covered pervious surfaces (natural green infrastructure), and when site design includes a balanced mixture of pervious and impervious surfaces, combined with structural green infrastructure. Both allow stormwater to enter into the ground (infiltrate) and into conventional infrastructure pipes and waterways more slowly, which reduces the threat of local flooding and the amount of pollution that reaches waterways.
Surface Infiltration Process  |
3.
Minimize erosion. In urban areas, increased volume and velocity of stormwater runoff causes erosion of both the land surface and the streambank. As erosion occurs, the path of the waterway changes and is more likely to intrude onto private properties, destabilize the land, and affect the roots of trees, making them unable to provide their full benefits.
Local Erosion Example  |
4.
Decrease pollutants. Increased impervious surface area does not allow rain and snowmelt to soak into the ground. This leads to excess stormwater runoff that washes pollutants off of impervious surfaces and carries them into the City's lakes and streams as shown in the image titled "Urban Wet Weather Flows." Pollutants from urban runoff include oil, grease, and toxic chemicals from motor vehicles, pesticides from lawns, viruses and bacteria from pet waste, road salts, heavy metals from roof shingles and motor vehicles, and thermal pollution from impervious surfaces. These pollutants can harm fish and wildlife populations, kill native vegetation, foul drinking water, and make recreational areas unsafe and unpleasant. (EPA. https://www.epa.gov/nps/nonpoint-source-urban-areas)
 |
5.
Decrease flooding. In a one-inch rainstorm, about 4,000 gallons of water falls on a typical residential lot in the City of Holland, which is enough to fill a swimming pool. In most development designs, about two-thirds of that water flows directly to storm drains.
Local Flooding Example  |
6.
Additional LID benefits.
a.
Increase property values.
b.
Increase retail sales.
c.
Energy savings.
d.
Reduce infrastructure costs.
e.
Reduce costs associated with flooding.
f.
Reduce water bills.
g.
Protect biodiversity.
h.
Increase mental health and worker productivity.
i.
Reduce crime.
C.
Site design to achieve LID goals. To ensure LID goals are met, the following standards are required, which shall be further specified in this article:
1.
Landscape requirements.
2.
Impervious surface maximums for certain zone districts.
3.
Green infrastructure requirements.
Traditional Parking Lot Design  | Preferred: LID Parking Lot Design  |
Traditional "Big Box" Site Layout  | Preferred: Equivalent LID Site Layout  |
Sec. 39-6.02 Landscape requirements (Sections 39-5.04, 39-5.08). [1]
[7-21-2021 by Ord. No. 1796]
A.
Applicability. The following developments shall comply with the landscape requirements in this article:
1.
New construction on any property requiring site plan approval.
2.
Building additions on any property requiring site plan approval.
3.
New parking lots or reconfigurations of parking lots, deemed significant enough by the approving authority, and requiring site plan approval.
4.
Street construction or reconstruction.
5.
Residential dwellings with one to four units shall only be subject to the street tree requirements of Section 39-6.02C. The Zoning Administrator and City Engineer may waive this requirement if deemed unnecessary.
B.
Landscape Requirements Table. The table below summarizes the landscape requirements, which are further specified in Section 39-6.02C through G. An Airport Zone District is exempt from these requirements.
Landscaping Type | Requirements |
|---|---|
Trees along street frontage | 1 tree per 30 feet |
Parking lot interior | 1 square foot of landscaping per 20 square feet of pavement |
Parking lot islands | 1 island with a tree per 20 spaces Parking lots under 20 spaces exempt Waiver may be permitted per Section 39-6.02D2e |
Parking lot perimeter | 1 square foot of landscaping per 20 square feet of pavement |
Building perimeter | Along all walls visible from a street or parking lot, required for buildings with a front setback greater than 2 feet |
Residential buffer | Required when property is adjacent to a residential zone district |
Green infrastructure | Site design meeting the requirements of Sections 39-6.06 through 39-6.08 |
C.
Street trees along the right-of-way.
1.
Requirements.
a.
One street tree per 30 linear feet measured at the center of each tree.
b.
Minimum 2.5 caliper in size as measured at 4.5 feet above grade.
c.
Existing street trees may be counted towards street tree requirements when stated and shown on the site plan.
d.
Street trees shall be planted in the right-of-way between the property line and the street unless the applicant states why this is not practical and shows an alternative on the site plan. The alternative shall be to either locate the trees a maximum of 10 feet from the right-of-way line or allow the planting of ornamental trees depending on the described rationale. The alternative will be reviewed and may be approved by the approving authority.
e.
Urban streets or when planting trees into concrete or brick, the following requirements shall be followed:
1)
Street trees shall be planted in accordance with MISS DIG and avoid impacts with existing utilities.
2)
Street trees planted in the public right-of-way become the property of the City of Holland.
3)
Streets trees shall be planted so as not to damage brick pavers and not to interfere with snowmelt systems.
4)
Street trees shall be irrigated with drip irrigation bubbles.
5)
Street trees shall be planted in raised beds or in frames, as shown in the graphic.
 | |
Street Tree Types: | |
• | Columnar if close to buildings |
• | Maple if able to grow out for a tree canopy |
• | Ornamental trees where approved |
• | Do not use locust trees in brick pavers |
2.
Species. Species shall be approved if they, in the opinion of the approving authority, meet these standards:
a.
Are not listed in Section 39-6.02G.3.
b.
Are generally resistant to salt, insects, diseases, damage, and drought.
c.
Provide adequate shade and aesthetics.
d.
Are not anticipated to damage street, nonmotorized, or utility infrastructure with their root or branch systems.
D.
Parking Lot Island Rain Garden, 16th Street
Interior parking lot and parking lot islands shall meet the following requirements:
1.
One square foot of interior parking lot landscaping is required per 20 square feet of parking lot pavement.
2.
Parking lot islands are required every 20 parking spaces minimum and shall meet the following requirements:
a.
Two hundred fifty square feet in size minimum;
b.
Include a minimum of one tree each; and
c.
Include additional landscaping, an approved ground cover, and/or structural green infrastructure. See Sections 39-6.06 through 39-6.08.
d.
Width minimums.
1)
No pedestrian pathway: seven feet.
2)
Pedestrian pathway: 11 feet. The pathway shall be a minimum five feet wide, with a minimum of three feet of landscaping on each side of the pathway.
e.
Waiver. A waiver may be approved by the approving authority to reduce the amount of parking lot islands required if the proposed interior parking lot landscaping still meets the intent of this section.
f.
Curbs. Parking lot islands shall have curbs, unless the island is designed as a vegetated swale, in which case curbs may be eliminated or inlets may be constructed within the curb to allow for stormwater flow. Vegetated swale design shall be approved by the City Engineer.
E.
Parking lot perimeter landscaping shall meet the following requirements:
1.
One square foot of perimeter parking lot landscaping is required per 20 square feet of parking lot pavement;
2.
Shall be planted surrounding parking lots and consist of a mixture of landscaping and permitted ground cover types; and
3.
Street trees shall count towards both street tree and parking lot perimeter requirements.
F.
Building perimeter landscaping shall meet the following requirements:
1.
Shall be planted along building walls visible from a public street or from a parking lot.
2.
Shall consist of a mixture of landscaping and approved ground cover types.
3.
Plantings shall be in the building setback when the building has a setback of two feet or greater. Plantings may be in an above ground planter when the building is setback between two feet and six feet from the street fronting property line.
4.
Waiver. The approving authority may waive these requirements if determined the design, use, or context of the property does not necessitate any or all building perimeter landscaping.
G.
Trees and ground cover type requirements.
1.
Minimum size at planting.
Plant Material | Minimum Plant Size | Where Measured |
|---|---|---|
Canopy/shade trees | 2.5-inch caliper | 4.5 feet above grade |
Ornamental trees | 2.0-inch caliper | 4.5 feet above grade |
Evergreen trees | 5 feet in height | Highest point, including leaves or flowers |
Shrubs | 3 feet in height | Highest point, including leaves or flowers |
2.
Ground cover types and requirements.
a.
Native vegetation. These are listed in the Michigan State University Native Plants and Ecosystem Services Southern Lower Peninsula Regional Plant List, or those species that occurred within nearby municipal boundaries prior to European settlement, according to available historical and scientific evidence. These species shall not require pesticide and herbicide applications, in order to eliminate toxicity to local wildlife and aquatic habitats.
Native Plants  Source: Rethinking the American Lawn, Ottawa Country Planning and Performance Improvement |
b.
Xeriscape: landscape that reduces or eliminates the need for irrigation. Xeriscape plants range from succulents to leafy, flowering trees.
c.
Rain garden plantings: no additional requirements.
d.
Perennial and annual flowers: no additional requirements.
e.
Mulch. One shrub per 50 square feet shall be planted on parking lot islands in addition to a tree. Ten percent of a parking lot island shall be a mulch planting bed with flowers or flowering shrubs. Turf grass shall only supplement other ground cover types to provide a multispecies landscape to increase biodiversity.
f.
Rocks and stones are not permitted as a primary ground cover and may only be used in building perimeter maintenance strips and in limited situations where mulching may otherwise be problematic with storm drainage plans, as approved by the approving authority.
3.
Prohibited species are invasive species artificially introduced to West Michigan, are nonnative, and are capable of out-competing and displacing native vegetation. Any species on the Michigan Department of Natural Resources list of invasive species shall be prohibited, in addition to those listed on the following table. Existing prohibited species shall be identified on a site plan and shall not count towards landscape requirements.
Common Name | Botanical Name |
|---|---|
Amur maple | Acer Ginnala |
Autumn olive | Elaeagnus Umbellata |
Black locust | Robinia Spp. |
Box elder | Acer Negundo |
Common buckthorn | Rhamnus Cathartica |
Common reed | Phragmites australis |
Flowering rush | Butomus umbellatus |
Garlic mustard | Alliaria petiolata |
Giant knotweed | Polygonum sahalinensis (Fallopia sachalinensis) |
Glossy buckthorn | Rhamnus Frangula |
Japanese barberry | Berberis Thunbergii |
Japanese knotweed | Fallopia japonica |
Lombardy poplar | Populus nigra var. italica |
Multiflora rose | Rosa Multiflora |
Purple loosestrife | Lythrum salicaria |
Russian olive | Elaeagnus Angustifolia |
Spotted knapweed | Centaurea Biebersteinii |
Tree of heaven | Ailanthus Altissima |
White mulberry | Morus alba |
H.
Tree replacement requirements.
1.
Applicability. Lots half an acre in size or greater, where five or more trees are proposed to be removed. These trees include:
a.
Deciduous trees over six inches in diameter at breast height (DBH).
b.
Coniferous trees over 10 feet in height.
c.
Healthy and noninvasive trees.
2.
Definition of "removed tree": The destruction, relocation, or cutting of a tree so that no portion larger than a stump remains intact on the site, or the mutilation of a tree to the point of near certain death.
3.
Replacement requirements. Trees shall either be replaced on-site at a ratio of one replacement tree per five removed trees, or a payment in lieu of trees shall be made per the requirements of Section 39-6.02H.4. Replacement trees shall comply with the following:
a.
Deciduous replacement trees shall be a minimum three inches DBH at planting.
b.
Coniferous replacement trees shall be a minimum 10 feet in height.
c.
Prohibited species listed in Section 39-6.02G.3 shall not be used as replacement trees.
d.
Replacement trees may be counted as required trees to meet other requirements of this section.
e.
Replacement trees shall be indicated on the site plan and planted in locations that, in the opinion of the approving authority, would have the greatest impact on reducing urban heat islands to make the City more resilient.
4.
Payment in lieu of trees. In lieu of planting trees on site, the applicant may pay a replacement fee per tree to the City of Holland to plant trees elsewhere within the City per the City's Tree Replacement Policy. The fee shall be $300 per tree.
5.
Professional tree survey. To verify the trees that shall be replaced, the applicant shall submit a professional tree survey performed by a licensed arborist, specifying which trees meet and do not meet the applicability requirements of Section 39-6.02H.1. The applicant shall then only be required to replace or provide a payment in lieu of trees for those specified.
6.
No professional tree survey. The applicant shall either replace or provide a payment-in-lieu-of-trees per the standards in Section 39-6.02H.3 for all trees, regardless of if they meet the applicability requirements in Section 39-6.02H.1. The number of trees proposed for replacement shall be approved by the approving authority.
7.
Exempt activities.
a.
Tree trimming and other routine maintenance that does not result in the destruction, mutilation, relocation, or cutting of a tree leaving more than a stump intact.
b.
Emergency removal or trimming of trees made necessary by a natural disaster, where the removal of the tree would prevent injury or damage to persons or property.
c.
Trees removed or trimmed by public utilities, public agencies, or when located in seasonal tree farms.
I.
Residential buffers are required when the property is located directly adjacent to a residential zone district.
1.
Buffering shall be required along all property lines separating a multifamily, nonresidential use, or a mixed-use development and a residential zone district. This requirement shall also apply if the development is located in a residential zone district.
2.
Buffering options.
a.
Wall.
1)
Minimum six feet in height.
2)
Solid or opaque and constructed from one of the following materials: masonry, brick, vinyl, or wood.
b.
Berm.
1)
Berm slopes shall not exceed a 4:1 horizontal to vertical ratio, with a top width of at least 1/2 the berm height, and a maximum height of three feet above the base of the berm.
2)
Berm slopes shall be stabilized with an approved ground cover type and be located outside of clear vision areas.
c.
Evergreen screen.
1)
An evergreen screen shall consist of a row of evergreen trees, forming a complete screen as viewed from the adjacent residential property.
2)
Evergreens shall be a minimum five feet in height at the time of planting.
d.
Landscape buffer area.
1)
Size: shall be a minimum 20 feet wide and shall extend along the entire property line.
2)
Trees: shall include a minimum of one tree per 500 square feet of landscape area. If the landscape buffer area is less than 500 square feet, then one tree shall be required.
3)
Shrubs: shall include a minimum of four shrubs per 500 square feet of landscape area.
e.
Preserved woodlands.
1)
Shall be a minimum 20 feet wide and shall extend along the entire property line abutting the residential property.
2)
At least 90% of existing trees six inches in diameter at breast height (DBH) or greater shall be retained.
J.
Clear vision corners required.
1.
Definition: a triangle formed on properties located at intersection corners in required front or secondary street setbacks.
2.
Measurement: established as a triangle formed by two points, each a minimum of 20 feet from the intersection of the property line and the line connecting the points.
3.
Height maximum. Landscaping shall be a maximum of three feet in height within a clear vision corner.
 |
K.
Additional landscape requirements.
1.
Species variety. The landscape plan shall not contain more than 33% of any single plant species. Landscape plans with fewer than 15 required plantings shall be exempt from this requirement.
2.
Stabilization. All landscape planting areas shall be stabilized and maintained with seed, sod, ground covers, mulch, or other approved materials to prevent soil erosion and allow stormwater infiltration. Mulch shall be spread in a manner that avoids soil compaction and shall not overflow into public rights-of-way.
3.
Protection of trees during construction. For every one inch of DBH, there should be a one-foot radius of protection. Appropriate guards shall be maintained around all existing trees to be retained. Remaining trees shall have sufficient room for their root structures to be maintained during construction and in site plan design.
4.
Timing of planting. All required plant material shall be planted prior to issuance of a final certificate of occupancy. In the event that the development is completed during a time of year when planting is impractical, a temporary certificate of occupancy may be issued with a deadline for installing the required landscaping and obtaining a permanent certificate of occupancy. A performance guarantee in the amount of the remaining improvements may be required.
5.
Completion of improvements. Tree stakes, tree ties, and tree wrap shall be removed after completion of the initial growing season.
[1]
Editor's Note: The title of this section was amended 2-2-2022 by Ord. No. 1812.
Sec. 39-6.03 Maintenance of landscaping and green infrastructure.
[7-21-2021 by Ord. No. 1796]
A.
Property owners shall take all reasonable measures to keep all landscaping alive and thriving and shall provide the following:
1.
A maintenance plan shall be included in the required written project summary stating which measures will be used to meet this requirement. This plan is separate from the maintenance agreement required by Chapter 29, Stormwater Ordinance.
2.
Irrigation of trees and shrubs is required. The approving authority may not require all landscaping to be irrigated, if requested, and if adequate green infrastructure is otherwise provided, as determined by the approving authority.
3.
Kept neat. All landscape materials, manufactured materials, and green infrastructure shall be kept in a neat, orderly, and thriving manner, free from debris and refuse.
4.
Removal of plant material. All diseased, unhealthy, and dead plant material or green infrastructure shall be removed immediately and replaced. Replacement landscaping shall be installed at or as close as possible to the size of the landscaping at the time of its removal.
5.
Minimum height of branches over sidewalk. A branch hanging over a public sidewalk or street shall be a minimum seven feet above grade and shall be maintained by the property owner. This maintenance shall include removal of dead branches or stubs that are or may become a menace to people on the public sidewalk or street.
6.
Not permitted on publicly owned trees.
a.
Wearing spurs when climbing trees unless done by a designated City of Holland employee or contractor.
b.
Wires shall not be attached to any tree.
c.
Signs shall not be attached to any tree.
7.
Trees shall not be removed from the right-of-way without permission of City of Holland's Parks and Recreation Department.
Sec. 39-6.04 Impervious surface maximums.
[7-21-2021 by Ord. No. 1796]
A.
Maximum impervious surface allowance. Impervious surfaces shall not exceed the maximum percentage for these zone districts. An increase in the impervious surface percentage may be provided upon request if the approving authority deems it necessary.
OS | HDR | CMU | GMU | RMU | I |
|---|---|---|---|---|---|
20% | 70% | 80% | 70% | 80% | 80% |
B.
Required open space. All areas not covered by buildings, parking areas, driveways, walkways, pedestrian plazas, other impervious surfaces, or water surfaces shall be planted with living vegetation, including canopy trees, shrubbery, and allowable ground cover types (Section 39-6.02G.2).
Sec. 39-6.05 Green infrastructure and stormwater management site design requirements.
[7-21-2021 by Ord. No. 1796]
A.
Intent. To meet the City of Holland's sustainability and resiliency goals, development needs to diversify the ways that stormwater runoff is collected, infiltrated, stored, and treated. Continued reliance solely on conventional infrastructure (water runoff into pipes and ponds) has proven to be unsustainable, especially with an increase in large storms and built development. The use of green infrastructure best management practices (BMPs) has proven to be effective in working in conjunction with conventional infrastructure to mimic natural processes and to meet low-impact development site design.
B.
Chapter 29 Stormwater Ordinance and UDO relationship. Most developments shall be required to obtain a stormwater permit from the City Engineer in addition to obtaining site plan approval. Chapter 29, Article VI, (Stormwater Ordinance) in the City's Code of Ordinances provides specific engineering standards to meet the ordinance and obtain a stormwater permit and references the applicant to the City of Holland's Stormwater Standards Manual for additional stormwater designs and details.
C.
This section of UDO requires the applicant to meet the Stormwater Ordinance requirements in specific ways that are critical for site design and achieving low-impact development goals. The two ways these requirements do this are through the use of structural green infrastructure best management practices and by making retention and detention ponds amenities in addition to being used for stormwater storage.
D.
Structural green infrastructure requirement.
1.
Structural green infrastructure best management practices (BMPs) shall be used to the maximum extent practicable to comply with the Chapter 29, Stormwater Ordinance, the adopted Stormwater Standards Manual, and to obtain a required stormwater permit. Credits are provided when using green infrastructure BMPs to meet the Stormwater Ordinance and are determined through stormwater permit calculations.
2.
Nonstructural BMPs are encouraged to be used in addition to using the required structural green infrastructure BMPs.
3.
Additional best practices include managerial and certain other structural and nonstructural BMPs that are encouraged to be used in addition to the required structural green infrastructure BMPs. These are listed in Section 39-6.08.
E.
Examples of green infrastructure BMPs.
1.
Structural green infrastructure best management practices (BMPs) are stormwater management and treatment techniques where devices are constructed for temporary storage and treatment of stormwater runoff. The following structural green infrastructure BMPs shall be approved in meeting the requirement in Section 39-6.05C.
a.
Pervious durable surface, Section 39-6.06.
b.
Rain garden/bioretention, Section 39-6.07A.
c.
Vegetated swale/bioswale, Section 39-6.07B.
d.
Vegetated green roof, Section 39-6.07C.
e.
Tree filter box, Section 39-6.07D.
f.
Constructed filter, Section 39-6.07E.
g.
Vegetated filter strip, Section 39-6.07F.
2.
Additional structural green infrastructure BMPs are listed in Appendix 3 of the City's Stormwater Standards Manual as "LID and Small Site Structural Best Management Practices." Other structural green infrastructure BMPs may be requested and approved by the approving authority.
3.
Nonstructural green infrastructure BMPs are stormwater treatment techniques that use natural measures to manage and treat stormwater and do not involve the construction or installation of devices. These types are encouraged, but are not required or countable in meeting the requirement of this section. They include:
a.
Native revegetation.
b.
Minimized soil compaction.
c.
Natural flow paths and sensitive area preservation.
d.
Wetland preservation.
e.
Tree preservation.
F.
Retention and detention pond amenities.
1.
Intent: to incorporate retention and detention ponds into the overall site design by designing them to be site amenities.
2.
Definitions. A "retention pond" is a permanent wet pond without a positive surface outlet, or a temporary wet pond that drains dry through infiltration into the ground, which is used to manage stormwater runoff. A "detention pond" is a permanent wet pond with a surface outlet, or a temporary wet pond that drains dry through the use of stormwater infrastructure.
3.
Design standards.
a.
Retention or detention ponds shall provide an amenity in the site's design that in the opinion of the approving authority provides a benefit beyond the storage of stormwater; and
b.
The location of the retention or detention pond shall, in the opinion of the approving authority, be able to amply benefit the proposed users of the site.
4.
Examples of approvable amenities are:
a.
Permanent wet pond.
1)
Fountain.
2)
Bench or benches.
3)
Walking path around or over the pond.
b.
Temporary wet pond.
1)
Park space with benches.
2)
Walking path around, on, or over the pond.
Sec. 39-6.06 Pervious durable surfaces.
[7-21-2021 by Ord. No. 1796]
A.
Intent. The use of pervious surfaces in site and street design mimics natural ground water infiltration, decreases the amount of post-construction stormwater runoff, and implements low-impact development (LID).
B.
"Pervious" definition: a surface covering the ground that allows the infiltration of water into the ground and provides stormwater treatment and storage without a surface outlet; also referred to as "permeable" or "porous."
C.
Pervious durable surface types. The following types of pervious surfaces shall be permitted to meet the durable paving requirements in Section 39-9.02 and are also a type of structural green infrastructure.
1.
Grass pavers: used for areas with occasional parking; not permitted for high-use areas.
2.
Permeable interlocking concrete pavers.
3.
Resin-bound paving.
4.
Permeable clay brick pavers: used for areas with pedestrian and vehicular traffic.
5.
Permeable asphalt.
6.
Permeable concrete.
7.
Plastic grids. These grids help reinforce driveways, parking lots, and fire lanes. Plastic grids can also be planted with grass. Used for areas with occasional parking; not permitted for high-use areas.
8.
Any type not listed but approved by the City Engineer and the approving authority.
Pervious and Nonpervious Split Parking Lot, Hope College  | Pervious Parking Lane  |
Permeable Grass Pavers, Detroit, MI  | Grass Pavers, Detroit, Michigan  |
D.
Benefits of pervious durable surfaces. (Source: 'Introduction to Green Infrastructure Techniques and Opportunities', Drummond Carpenter, PLLC)
1.
Eliminates or minimizes runoff.
2.
Recharges groundwater.
3.
Traps suspended solids and pollutants.
4.
Melting water seeps through the pavement instead of freezing to increase slip and fall protection.
5.
Reduces surface temperatures and, therefore, the heat island effect.
6.
Eliminates the need for retention basins and water collection areas.
7.
Eliminates costs for retention basins, curbs, gutters, and other water collection installations.
8.
In winter conditions, typically requires much less salt or other de-icing products than traditional pavement types.
9.
Lower installation costs (no underground piping, storm drains, or sloping/grading needed).
10.
Low life-cycle costs with an equal life expectancy to that of regular concrete (20 to 40 years when correctly installed).
Sec. 39-6.07 Additional examples of structural green infrastructure best management practices (BMPs).
[7-21-2021 by Ord. No. 1796]
A.
Rain gardens, also called "bioretention facilities," provide stormwater treatment, water storage, and uptake with or without a surface outlet. They are best used in drainage areas and can be used in a combination with an underdrain BMP to provide extended detention for channel protection. See tree box, Section 39-6.07D. Rain gardens are designed to reduce the stormwater flow rate, quantity, and pollutant load of runoff from impervious surfaces to manage water on-site. Rain gardens rely on plants and natural or engineered soil medium to retain stormwater and increase infiltration, while remediating and filtering pollutants carried by urban runoff. They also provide a method to reuse and optimize water, reducing the need for additional irrigation. Rain gardens decrease ambient air and water temperature to reduce the urban heat-island effect.
1.
Common locations for rain gardens are in or along a:
a.
Parking lot island.
b.
Parking lot perimeter.
c.
Field of turf grass.
d.
Street.
 |
Parking Lot Island Rain Garden  | Parking Lot Perimeter - Curb Cut Rain Garden  |
Field Rain Garden  | Street Bioretention/Rain Gardens  |
B.
Vegetated swales are similar to rain gardens, but they focus more on channeling stormwater off from streets and parking lots whereas rain gardens focus on retaining water on site. This BMP is a stormwater conveyance designed to slow, filter, and infiltrate stormwater and is used for small drainage areas with concentrated water flow. A vegetated swale is typically designed with sufficient bottom slope to convey water while filtering it.
Vegetated Swale Examples  |
C.
Vegetated green roofs provide stormwater treatment and water storage with a surface overflow. They are most practical for flat or slightly sloped rooftops. They provide a stormwater buffer, purify the air, reduce ambient temperature, regulate indoor temperates, save energy, and encourage biodiversity.
Green Roof Aerial  |
D.
Tree filter boxes and planter boxes are infiltration filters that combine structural green infrastructure BMPs, nonstructural green infrastructure BMPs, and a perforated underdrain pipe, to retain and filter water. They are most often used on the sides of or center of streets and in parking lot islands.
Tree Filter Box  |
Tree Filter Box  |
Trees planted with pervious pavement reduce stormwater flow and reduce associated pollution  |
E.
Constructed filters are underdrained structures or excavated areas containing a layer of sand, compost, organic material, peat, or other media that reduce pollutant levels in stormwater runoff by filtering sediments, metals, hydrocarbons, and other pollutants before the stormwater reaches the underdrain to be routed to the storm sewer system. Constructed filters are suitable for sites where infiltration is not possible or practical. Any one of the aforementioned bioretention BMPs can also operate as a constructed filter if it has an impervious bottom/sides and includes an underdrain.
Constructed Filter Graphic  |
F.
Vegetated filter strips are permanent, maintained strips of vegetation designed to slow runoff velocities and filter out sediment and other pollutants from urban stormwater. Filter strips require the presence of sheet flow across the strip, which can be achieved through the use of level spreaders. Frequently, filter strips are designed for pretreatment where runoff is directed from a parking lot into another BMP.
Vegetated Filter Strip. Slope design may vary from site to site.  |
Sec. 39-6.08 Additional best practices.
[7-21-2021 by Ord. No. 1796]
A.
The following stormwater management and green infrastructure practices are encouraged by UDO because all uses impact sustainability and can assist in meeting the City of Holland's low-impact development (LID) goals.
1.
Composting.
2.
Planting of trees on residential properties.
3.
Mulching of bare soil.
4.
Lawn reduction.
5.
Water-efficient landscaping.
6.
Washing cars on a lawn area.
7.
Downspout extensions to direct water away from a building foundation, directed into the lawn, landscape, or a rain garden.
Downspout Extensions  |
8.
Water harvesting: use of rain barrels or other mechanisms to collect and store rainwater from roofs to use for irrigation.
Rain Barrel  |
9.
Residential rain gardens.
Residential Rain Garden  |