Sustainable Site Development: Rain Gardens & Bioswales Construction(Chicago, July 2010)


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In the presentation, Barrett will discuss how rain gardens and bioswales protects, restores, and mimics the natural water cycle, and how they can help develop a natural approach to water efficiency, and relieve storm water management issues.

“The American Society for Civil Engineers gave the United States’ water systems a grade of ‘D-,’ the lowest of any America infrastructure,” said Barrett. “Through increased use of rain gardens and bioswales, we can improve our water systems and create a better environment for plants, animals, and people.”

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  • Tom Barrett is owner of Green Water Infrastructure. He has over thirty years of successful landscape industry experience and is known as an accomplished corporate growth and change agent.

    Mr. Barrett has held various leadership positions at such industry leaders as Rain Bird, Kenney Machinery, Ewing, Netafim, and MacAllister Machinery. He has worked with such projects as Animal Kingdom at Walt Disney World in Florida. He has won numerous awards in Quality and Process Improvement, and is a frequent contributor of articles for numerous publications.

    Mr. Barrett holds a Bachelor of Science in Agronomy and Plant Genetics from the University of Arizona. He furthered his studies in architecture at Syracuse Univ. He holds multiple certifications in irrigation and water conservation. Tom is a member of the Indiana Nursery and Landscape Association, as well as the International Irrigation Association, in which he chairs the Communications Committee. He is an approved instructor for the Irrigation Association.

    Tom Barrett has been sharing his expertise and his ideas in energetic and dynamic presentations for over twenty years. He is a master trainer. His presentations empower people to become masters of change, rather than victims of circumstance by developing tools for transformative thinking.

    Currently, Tom delivers over thirty presentations each year to organizations around the country. He is well-suited to talk to us today about Rain Gardens & Bioswales. Please join me in welcoming, TOM BARRETT!

  • Green Infrastructure, Green Highways, and Green Streets will be the foundation for the rebuilding and expansion of our nations infrastructure and a key to our economic growth in the 21st Century. Green is the development of innovative approaches and strategies on how to integrate integrate grey and green infrastructure in order to protect water resources and promote sustainable design and community development. We have an opportunity to use a comprehensive approach that takes advantage of our experience on pilot projects, research, the development of standards and specifications, manuals of practice, training, and environmental management systems in order to integrate and institutionalize green approaches.

  • At the largest scale, the preservation and restoration of natural landscape features (such as forests, floodplains and wetlands) are critical components of green stormwater infrastructure. By protecting these ecologically sensitive areas, communities can improve water quality while providing wildlife habitat and opportunities for outdoor recreation.
    On a smaller scale, green infrastructure practices include rain gardens, porous pavements, green roofs, infiltration planters, trees and tree boxes, and rainwater harvesting for non-potable uses such as toilet flushing and landscape irrigation.

    Picture the grime of city streets -- oil, grease and soot from cars and trucks; pet waste; trash and litter; sediment and debris from construction sites; and a mix of toxic chemicals. Now picture the same streets after a rainstorm. They look cleaner, right? Sure, but the debris and contaminants haven't just disappeared -- they've been swept through street drains and underground pipes then washed directly into the nearby river, lake or bay.
    Wherever humans have paved or built over the natural world, dirty rainwater tends to run straight into our waterways, contaminating the water, destroying habitat and damaging property. Known as urban runoff, this type of pollution can have serious consequences, from fouling drinking water to closing beaches and poisoning shellfish beds. Indeed, the U.S. Environmental Protection Agency now considers urban runoff and pollution from other diffuse sources the greatest contaminant threat to our nation's waters. The good news is that there are a number of proven solutions that towns and cities can use to reduce runoff pollution.
    One new and exciting approach has emerged in recent years. Called "low-impact development," it uses both simple common sense and technology -- strategically placed beds of native plants, rain barrels, "green roofs," porous surfaces for parking lots and roads, and other tools -- to help rainfall evaporate back into the atmosphere or soak into the ground, rather than polluting the nearest water body. In effect, low-impact development mimics nature's own filtering systems. The result is less water pollution from dirty runoff, less flooding, replenished groundwater supplies -- and often, more natural-looking, aesthetically pleasing cityscapes.

  • Today we rapidly collect it, condense it, and move it into our local waterways.

    In a forest, 92% to 98% of that water is return to the environment in a natural fashion. 8% goes into the atmosphere as evaporation and transpiration. The rest goes though the soil trough a natural cleansing process and is returned to our lakes, streams, and ground water.
  • Over the last twenty years our population has grown 8%. Our impermeable surface areas have increased 40%
  • The problem is we combine stormwater with wastewater and overflow our sewerage systems. 749 communities have combined stormwater/wastewater systems. As little ¼” of rain causes them to overflow, dumping raw, untreated sewer water into our waterways.
  • Stormwater is the largest contributor to water pollution today.
  • 40% of our potable water supply systems exceeding the EPA’s permissible levels for atrazine.

  • Heat from Earth is trapped in the atmosphere due to high levels of carbon dioxide (CO2) and other heat-trapping gases that prohibit it from releasing heat into space -- creating a phenomenon known as the "greenhouse effect." Trees remove (sequester) CO2 from the atmosphere during photosynthesis to form carbohydrates that are used in plant structure/function and return oxygen back to the atmosphere as a byproduct. About half of the greenhouse effect is caused by CO2. Trees therefore act as a carbon sink by removing the carbon and storing it as cellulose in their trunk, branches, leaves and roots while releasing oxygen back into the air.
    Trees also reduce the greenhouse effect by shading our homes and office buildings. This reduces air conditioning needs up to 30%, thereby reducing the amount of fossil fuels burned to produce electricity. This combination of CO2 removal from the atmosphere, carbon storage in wood, and the cooling effect makes trees a very efficient tool in fighting the greenhouse effect.  (11)
    One tree that shades your home in the city will also save fossil fuel, cutting CO2 buildup as much as 15 forest trees. (16)
    Approximately 800 million tons of carbon are stored in U.S. urban forests with a $22 billion equivalent in control costs. (1)
    Planting trees remains one of the cheapest, most effective means of drawing excess CO2 from the atmosphere. (15)
    A single mature tree can absorb carbon dioxide at a rate of 48 lbs./year and release enough oxygen back into the atmosphere to support 2 human beings. (10)
    Each person in the U.S. generates approximately 2.3 tons of CO2 each year. A healthy tree stores about 13 pounds of carbon annually -- or 2.6 tons per acre each year. An acre of trees absorbs enough CO2 over one year to equal the amount produced by driving a car 26,000 miles. An estimate of carbon emitted per vehicle mile is between 0.88 lb. CO2/mi. – 1.06 lb. CO2/mi. (Nowak, 1993). Thus, a car driven 26,000 miles will emit between 22,880 lbs CO2 and 27,647 lbs. CO2. Thus, one acre of tree cover in Brooklyn can compensate for automobile fuel use equivalent to driving a car between 7,200 and 8,700 miles. (8)
    If every American family planted just one tree, the amount of CO2 in the atmosphere would be reduced by one billion lbs annually. This is almost 5% of the amount that human activity pumps into the atmosphere each year. (17)
    The U.S. Forest Service estimates that all the forests in the United States combined sequestered a net of approximately 309 million tons of carbon per year from 1952 to 1992, offsetting approximately 25% of U.S. human-caused emissions of carbon during that period.
    Over a 50-year lifetime, a tree generates $31,250 worth of oxygen, provides $62,000 worth of air pollution control, recycles $37,500 worth of water, and controls $31,250 worth of soil erosion. (2)
    Reduction of Other Air Pollutants:

    Trees also remove other gaseous pollutants by absorbing them with normal air components through the stomates in the leaf surface. (3)
    Some of the other major air pollutants and their primary sources are:
    Sulfur Dioxide (SO2)- Coal burning for electricity/home heating is responsible for about 60 percent of the sulfur dioxide in the air.  Refining and combustion of petroleum products produce 21% of the SO2.
    Ozone (O3) -  is a naturally occurring oxidant, existing in the upper atmosphere. O3 may be brought to earth by turbulence during severe storms, and small amounts are formed by lighting. Most O3 - and another oxidant, peroxyacetylnitrate (PAN) - come from the emissions of automobiles and industries, which mix in the air and undergo photochemical reactions in sunlight. High concentrations of O3 and PAN often build up where there are many automobiles.
    Nitrogen oxides - Automotive exhaust is probably the largest producer of NOx. Oxides of nitrogen are also formed by combustion at high temperatures in the presence of two natural components of the air; nitrogen and oxygen.
    Particulates are small (<10 microns) particles emitted in smoke from burning fuel, particular diesel, that enters our lungs and cause respiratory problems. (10)
    There is up to a 60% reduction in street level particulates with trees. (1)
    In one urban park (212 ha.) tree cover was found to remove daily 48lbs. particulates, 9 lbs nitrogen dioxide, 6 lbs sulfur dioxide, and 2 lb carbon monoxide ($136/day value based upon pollution control technology) and 100 lbs of carbon. (1)
    One sugar maple (12" DBH) along a roadway removes in one growing season 60mg cadmium, 140 mg chromium, 820 mg nickel, and 5200 mg lead from the environment. (1)
    Planting trees and expanding parklands improves the air quality of Los Angeles county. A total of 300 trees can counter balance the amount of pollution one person produces in a lifetime. (10)

    Urban Forests Protect Our Water
    Trees reduce topsoil erosion, prevent harmful land pollutants contained in the soil from getting into our waterways, slow down water run-off, and ensure that our groundwater supplies are continually being replenished. For every 5% of tree cover added to a community, stormwater runoff is reduced by approximately 2%. (1)
     Research by the USFS shows that in a 1 inch rainstorm over 12 hours, the interception of rain by the canopy of the urban forest in Salt Lake City reduces surface runoff by about 11.3 million gallons, or 17%. These values would increase as the canopy increases. (13)
    Along with breaking the fall of rainwater, tree roots remove nutrients harmful to water ecology and quality. (13)
    Trees act as  natural pollution filters. Their canopies, trunks, roots, and associated soil and other natural elements of the landscape filter polluted particulate matter out of the flow toward the storm sewers. Reducing the flow of stormwater reduces the amount of pollution that is washed into a drainage area. Trees use nutrients like nitrogen, phosphorus, and potassium--byproducts of urban living--which can pollute streams. (20)

    Urban Forests Save Energy

    Homeowners that properly place trees in their landscape can realize savings up to 58% on daytime air conditioning and as high as 65% for mobile homes. If applied nationwide to buildings not now benefiting from trees, the shade could reduce our nation’s consumption of oil by 500,000 barrels of oil/day. (12) 
    The maximum potential annual savings from energy conserving landscapes around a typical residence ranged from 13% in Madison up to 38% in Miami. Projections suggest that 100 million additional mature trees in US cities (3 trees for every unshaded single family home) could save over $2 billion in energy costs per year. (10)
    Trees lower local air temperatures by transpiring water and shading surfaces. Because they lower air temperatures, shade buildings in the summer, and block winter winds, they can reduce building energy use and cooling costs. (6)
    Help to cool cities by reducing heat sinks. Heat sinks are 6-19 degrees Fo warmer than their surroundings (Global Releaf GA). A tree can be a natural air conditioner. The evaporation from a single large tree can produce the cooling effect of 10 room size air conditioners operating 24 hours/day. (18)
    USFS estimates the annual effect of well-positioned trees on energy use in conventional houses at savings  between 20-25% when compared to a house in a wide-open area. (USFS meteorologist Gordon Heisler)(13).

    Urban Forests Can Extend the Life of Paved Surfaces

    The asphalt paving on streets contain stone aggregate in an oil binder. Without tree shade, the oil heats up and volatizes, leaving the aggregate unprotected.

    Vehicles then loosen the aggregate and much like sandpaper, the loose aggregate grinds down the pavement. Streets should be overlaid or slurry sealed every 7-10 years over a 30-40 year period, after which reconstruction is required.

    A slurry seal costs approximately $0.27/sq.ft. or $50,000/linear mile. Because the oil does not dry out as fast on a shaded street as it does on a street with no shade trees, this street maintenance can be deferred. The slurry seal can be deferred from every 10 years to every 20-25 years for older streets with extensive tree canopy cover. (19)

    Urban Forests Can Increase Traffic Safety
    Trees can also enhance traffic calming measures, such as narrower streets, extended curbs, roundabouts, etc. Tall trees give the perception of making a street feel narrower, slowing people down. Closely spaced trees give the perception of speed (they go by very quickly) slowing people down. A treeless street enhances the perception of a street being wide and free of hazard, thereby increasing speeds. Increased speed leads to more accidents.
    Trees can serve as a buffer between moving vehicles and pedestrians. 
    Street trees also forewarn drivers of upcoming curves. If the driver sees tree trunks curving ahead before seeing the road curve, they will slow down and be more cautious when approaching curves. (16)

    Urban Forests Can Improve Economic Sustainability
    The scope and condition of a community's trees and, collectively, its urban forest, is usually the first impression a community projects to its visitors. A community's urban forest is an extension of its pride and community spirit.
    Studies have shown that:
    Trees enhance community economic stability by attracting businesses and tourists.
    People linger and shop longer along tree-lined streets.
    Apartments and offices in wooded areas rent more quickly and have higher occupancy rates.
    Businesses leasing office spaces in developments with trees find their workers are more productive and absenteeism is reduced. (11)

    Urban Forests Can Increase Real Estate Values
    Property values increase 5-15% when compared to properties without trees (depends on species, maturity, quantity and location)
    A 1976 study that evaluated the effects of several different variables on homes in Manchester, Connecticut, found that street trees added about $2686 or 6% to the sale price of a home. (10)
    A more recent study indicated that trees added $9,500, or more than 18 percent, to the average sale price of a residence in a suburb of Rochester, New York. (8)

    Urban Forests Can Increase Sociological Benefits
    Two University of Illinois researchers (Kuo and Sullivan) studied how well residents of the Chicago Robert Taylor Housing Project (the largest public housing development in the world) were doing in their daily lives based upon the amount of contact they had with trees, and came to the following conclusions:
     Trees have the potential to reduce social service budgets, decrease police calls for domestic violence, strengthen urban communities, and decrease the incidence of child abuse according to the study. Chicago officials heard that message last year. The city government spent $10 million to plant 20,000 trees, a decision influenced by Kuo’s and Sullivan’s research, according to the Chicago Tribune.
    Residents who live near trees have significantly better relations with and stronger ties to their neighbors.
    Researchers found fewer reports of physical violence in homes that had trees outside the buildings. Of the residents interviewed, 14% of residents living in barren conditions have threatened to use a knife or gun against their children versus 3% for the residents living in green conditions. (15)
    Studies have shown that hospital patients with a view of trees out their windows recover much faster and with fewer complications than similar patients without such views. (13)
    A Texas A&M study indicates that trees help create relaxation and well being.
    A U.S. Department of Energy study reports that trees reduce noise pollution by acting as a buffer and absorbing 50% of urban noise.  

  • A rain garden uses native soil and deep rooted native plants of the wet mesic prairie and sedge-meadow

  • Bioswales differ from Rain Gardens because they are usually engineered soils with an underdrain. Rain Gardens are preferable because they are less expensive and less susceptible to failure.

    Indiana Native Plant and Wildflower Society home page
    The Environmental Protection Agency Web page on landscaping with native wildflowers and grasses. Includes
    online handbook on building and maintaining a natural landscape, information on weed laws and more.
    Wild Ones - Natural Landscapers home page. Offers tips on landscaping with native plants.

  • Why Choose Green Infrastructure?
    Nature works best: Rivers, streams, wetlands, floodplains, and forests provide a suite of critical services like clean water and flood protection, and should be viewed as essential and effective components of our water infrastructure. New York City has great quality tap water because the city invested in water protection by purchasing land around its Catskills reservoirs to ensure that polluted runoff from roads and lawns doesn’t enter the water supply.The city’s $600 million investment in Catskills land protection and restoration did the job of $6 billion in capital costs to construct a water filtration plant as well as $200-300 million in annual operation and maintenance costs.
    We can’t waste money: Spending money wisely means investing in multi-purpose solutions that lower costs and provide more benefits. Recently, the City of Indianapolis announced that by using wetlands, trees, and downspout disconnection to reduce stormwater flows into their combined sewer system, the City will be able to reduce the diameter of the planned new sewer pipe from 33’ to 26’, saving over $300 million.
    We must enhance community safety and enjoyment: Traditional infrastructure isn’t designed to handle the increased floods and droughts that come with global warming, so we need a modern approach to protect public health, safety, and quality of life. Green solutions give communities the security and flexibility they need. Napa, CA solved flooding problems by choosing to restore the Napa River’s natural channel and wetlands, rather than lining the river with concrete. The effort has protected 2,700 homes and prevented $26 million in flood damage each year, and has created new parks and open space.
    Return to Top
    Green Infrastructure is Good for Jobs and the Economy
    These green solutions create good jobs in many sectors, including plumbing, landscaping, engineering, building, and design. Green infrastructure also supports supply chains and the jobs connected with manufacturing of materials including roof membranes, rainwater harvesting systems, and permeable pavement.
    New York City’s broad sustainability plan, PlaNYC, includes substantial investments in green infrastructure to reduce stormwater and sewage overflows and protect drinking water supplies. The City estimates that full implementation of PlaNYC will create 4,449 water infrastructure jobs of all types per year.
    Other countries are utilizing green water technologies at a much higher rate than the United States. We cannot afford to fall behind other nations in this vital area, it is a matter of economic competitiveness as well as quality of life and community security.A New Vision for Water
    We are at a crossroads today in how we manage our water. Traditional water infrastructure will continue to play a role, but it is static, solves only a single problem, and requires a huge expense to build and maintain. We must use this transformational moment to move from old 19th Century infrastructure to a wiser combination of green and traditional infrastructure that will meet the needs of the 21st Century.

  • Sustainable Site Development: Rain Gardens & Bioswales Construction(Chicago, July 2010)

    1. 1. Constructing Rain Gardens & Bioswales By Tom Barrett Green Water Infrastructure, Inc.
    2. 2. The GREEN Economy
    3. 3. How Much Rain Falls in Chicago? January - 1.86" Image of Rain Falling February - 1.58" March - 2.59" April - 3.28" May - 3.75" June - 4.08" July - 3.39" August - 3.38" September - 2.91" October - 2.65" November - 2.09" December - 1.88" Total 33.44"
    4. 4. How Much Water Falls in Chicago? 2,500 sq. ft. Roof January - ,727 gallons 2 Image of Rain Falling February - ,540 2 March - ,130 4 April - 5,735 May - ,268 5 June - 5,657 July - ,470 5 August - ,200 7 September - ,096 5 October - ,223 4 November - 4,691 December - 3,787 Total 6,525 5
    5. 5. How Much Water Falls in Chicago? 3 Acre Commercial Property January - 42,560 gallons 1 Image of Rain Falling February - 32,784 1 March - 15,876 2 April - 299,783 May - 75,344 2 June - 295,710 July - 85,934 2 August - 76,358 3 September - 66,383 2 October - 20,764 2 November - 245,203 December - 197,954 Total 2,954,654
    6. 6. How Much Water Falls in Chicago? City Block (660’ x 660’ – 10 acres) January - 75,195 gallons 4 February - 42,610 4 March - 19,581 7 April - 999,267 May - 17,805 9 June - 985,690 July - 53,105 9 August - ,254,515 1 September - 87,936 8 October - 35,873 7 November - 817,335 December - 659,842 Total 9,848,756
    8. 8. Stormwater Mitigation Stormwater Mitigation Stormwater Mitigation Stormwater Mitigation Stormwater Mitigation
    9. 9. Image of Rain Falling
    11. 11. Peak Flow (1 Acre Site) Grass Field Roof 1 Year Storm 1.4 cfs 4.3 cfs 2 Year Storm 2.1 cfs 5.4 cfs 10 Year Storm 4.3 cfs 8.0 cfs 25 Year Storm 5.7 cfs 9.5 cfs 100 Year Storm 8.0 cfs 12.0 cfs cfs – cubic feet per second
    12. 12. Peak Flow (1 Acre Site) Grass Field Roof 1 Year Storm 10.5 gps 32.2 gps 2 Year Storm 15.7 gps 40.4 gps 10 Year Storm 32.2 gps 59.8 gps 25 Year Storm 42.6 gps 71.1 gps 100 Year Storm 59.8 gps 89.8 gps gps – gallons per second
    13. 13. Peak Flow (1 Acre Site) Grass Field Roof 1 Year Storm 630 gpm 1,932 gpm 2 Year Storm 942 gpm 2,424 gpm 10 Year Storm 1,932 gpm 3,588 gpm 25 Year Storm 2,556 gpm 4,266 gpm 100 Year Storm 3,588 gpm 5,388 gpm gpm – gallons per minute
    14. 14. Peak Flow (2,500 sq. ft. Roof) Grass Field Roof 1 Year Storm 0.08 cfs 0.25 cfs 2 Year Storm 0.12 cfs 0.31 cfs 10 Year Storm 0.25 cfs 0.46 cfs 25 Year Storm 0.33 cfs 0.55 cfs 100 Year Storm 0.46 cfs 0.69 cfs cfs – cubic feet per second
    15. 15. Peak Flow (2,500 sq. ft. Roof) Grass Field Roof 1 Year Storm 0.60 gps 1.85 gps 2 Year Storm 0.90 gps 2.32 gps 10 Year Storm 1.85 gps 3.43 gps 25 Year Storm 2.44 gps 4.08 gps 100 Year Storm 3.43 gps 5.15 gps gps – gallons per second
    16. 16. Peak Flow (2,500 ft. sq. Roof) Grass Field Roof 1 Year Storm 36 gpm 111 gpm 2 Year Storm 54 gpm 139 gpm 10 Year Storm 111 gpm 206 gpm 25 Year Storm 147 gpm 245 gpm 100 Year Storm 206 gpm 309 gpm gpm – gallons per minute
    17. 17. Change in Peak Runoff Flow Before and after Development 300% 225% 150% 75% 0% 1 Year Storm Year Storm Year Storm Year Storm Year Storm 2 10 25 100 Stormwater Effects of Urbanization
    18. 18. PLANTING TREES
    19. 19. Stormwater Mitigation – Collection runoff near the source – Slow it down – Soak it in – Filter it – Apply it to the landscape – Create habitats
    20. 20. Rain Garden A Low Spot Catches Stomwater Deep Rooted Plants
    22. 22. Bioswales Engineered Soils Underdrain
    23. 23. Location Rain gardens are Plant Choices often located at the end of a roof or Choose plants based drain spout. on the need for light and soil type. Depth Size Soil A Rain Garden usually A tpical mix is 65% A typical Rain Garden five to ten percent sand, 15% top soil, is between four to of the impervious 25% organic matter. eight inches deep. surface area. RAIN GARDENS
    24. 24. RAIN GARDEN
    25. 25. RAIN GARDEN
    28. 28. Street Edges & Medians
    29. 29. Parking Lot Edges
    30. 30. Parking Lot Islands
    31. 31. Driveway Edge
    32. 32. Downspout
    34. 34. Criteria Meet Stormwater Utility Clearance Regulations Soil Investigation Detention Volume Percolation Test Fix Drainage Issue Fix Erosion Issue
    35. 35. Criteria Near the Rainwater Distributed Evenly Source Across the Site Avoid “End-of Pipe” Small Tributary Areas because of (usually 1 acre or less) Sedimentation Issues Typically 10’ to 20’ from Buildings
    36. 36. Soil Investigation •Soil Profile to Five Feet •Soil Compaction Level •Depth to Groundwater and Bedrock
    37. 37. Percolation Test •Soil Infiltration Rate •Key Design Parameter •Percolates water in 24 Hours
    38. 38. Sizing Determine Design Native vs. Engineered Goals Soil Assessment Calculate Runoff Volume Determine Allowable Depth Calculate Surface Area
    39. 39. Sizing Runoff Volume = Precipitation x Drainage Area x Runoff Coefficient RV=Pr x D(area) x C(un
    40. 40. Depth Based Upon Infiltration Rate Infiltration in One Day Avoid Misquotes Maximum Depth 18” for Safety
    41. 41. Surface Area Area of Rain Garden (ft2) = Runoff Capture Volume (ft3) / Average Depth (ft) A=V/D(average)
    42. 42. Engineered Soils Bioretention Space Available Volume of Stormwater Drain Faster (the garden can be deeper and not as wide)
    43. 43. Plants - Bottom Palm Sedge Soft Rush Tussock Sedge Marsh Milkweed Blue Flag Iris Joe-Pye Weed
    44. 44. Plants - Sides Purple Coneflower Showy Goldenrod Smooth Phlox
    45. 45. Plants - Edges Butterfly Milkweed Little Bluestem Aromatic Aster
    46. 46. Inlets
    47. 47. Outlets
    48. 48. Curb Cut & Filter Strip Controls Sedimentation
    49. 49. Splash Blocks Prevents Erosion and Gullies
    51. 51. Green • Water • Infrastructure Green • Water • Infrastructure Green • Water • Infrastructure Green • Water • Infrastructure Green • Water • Infrastructure
    52. 52. Thank You