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IndependenceParkway<br />07186<br />Green Road Design Challenge<br />Tidal Road<br />Aerial View<br />
Concepts<br />The concepts focus on incorporating the highest ranked Best Management Practices LID applications into this ...
Design Concepts<br />Existing<br />The existing road is bordered on the east by ditches of varying depth from 2’ to 3’.   ...
Rain gardens and grass swales as bioretention elements for storm water management
Green walls designed of hog wire and metal poles
Existing banners relocated to short columns
Lighting is provided by solar panels mounted on green wall
Dry stacked retaining walls allow the ditch to be widened.</li></ul>Tidal Road<br />
Design Concepts<br />Existing<br />Existing two lane roadway of 28’-0” is constructed of crushed limestone with asphalt to...
Design Concepts<br />Existing Monument<br />The existing marker is in need of enhancement to provide recognition deserving...
Design Concepts<br />Existing Roadside Banners<br />Entrance to San Jacinto Monument<br />The San Jacinto Monument entranc...
Design Concepts<br />Monument Plan<br />Monument Elevation<br />The existing historical marker is presently obscure and un...
Design Concepts<br />Independence Parkway Easement Elevation<br />The “green wall” designed of metal poles and hog wire.  ...
Design Concepts<br />We envision an opportunity for a bike path that is a part of the State Park routes to Independence Pa...
Design Concepts<br />Proposed Roadway Perspective<br />As a major cost savings measure we chose the maintain the existing ...
Road Sections<br />
Hydrographs<br />The two comparative provides hydrologic analysisof the stormwater drainage flows as it relates to this ro...
Hydrographs<br />HEC-HMS software is used in our office and therefore was utilized to create this hydrological data. The p...
Porous Asphalt Road <br />               “It’s not just for parking lots anymore”<br />Porous asphalt offers a powerful so...
Permeable Paver Shoulders<br />Permeable Pavers<br />Permeable pavers are consist of concrete pavers with joints filled wi...
GrassCrete Median<br />GrassCrete <br />GrassCrete provides a natural wetlands environment that works to decrease the impe...
Rain Gardens <br />Rain gardens offers natural filtration of rainwater run-off …<br />Rain gardens are implemented as part...
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GREEN ROADWAY Team 07186 Competition Submittal

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Electronic submittal from team of Harris County Public Infrastructure Department

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GREEN ROADWAY Team 07186 Competition Submittal

  1. 1. IndependenceParkway<br />07186<br />Green Road Design Challenge<br />Tidal Road<br />Aerial View<br />
  2. 2. Concepts<br />The concepts focus on incorporating the highest ranked Best Management Practices LID applications into this roadway design project. These LID techniques are deemed most effective in handling stormwater run-off and removal of pollutants. We chose Seattle’s design criteria as most applicable to Harris County’s infrastructure challenges.<br />Our decision to retain the existing roadway was based on providing solutions that were the least intrusive to the environment and provided cost savings to Harris County’s infrastructure cost over the long-term By utilizing the existing road as part of the design the County would save as much as $300,000 in demolition cost as well as $2 million in roadway construction cost. Retrofitting the existing two lane roadway section also provides an opportunity to mill and reuse/recycle the existing asphalt top, another cost savings.<br />The roadway design consist of porous asphalt, a Grasscrete median, permeable paver shoulders with rain gardens and bio-retention swales at roadsides. As architectural enhancements green walls, short columns housing the existing Precinct 2 banner poles and a Harris County emblem compose the Independence Parkway corridor. <br />At “points of interest” enhancements include a pull-off of permeable pavers and other decorative elements that invite drivers to stop and discover Harris County’s history.<br />Porous asphalt has advanced over the past decade and proven successful on high speed roads in Europe. The major advantages of porous asphalt are the reduction in hydroplaning and a reduction in spray from tires. Other benefits include noise reduction and less wear on tires due to less road friction. Although porous asphalt cost are about the same as conventional road construction cost will be reduced as the material gain popularity. Also, with porous asphalt roads drainage pipes are eliminated and a cost savings. <br />Centered along the roadway is a median constructed of Grasscrete. Grasscrete was chosen to create a combined systems that promote bio-filtration of rainwater run-off to improve the quality of stormwater leaving the roadway.<br />Instead of ditches that typically dot Harris County’s roadways rain gardens and bio-retention swales are designed with year round native wildflowers and varied grasses. These gardens are designed to remove pollutants from rainwater run-off before it enters other water sources. Rain gardens are an opportunity for the County to embrace the simplicity of nature thereby allowing it to prevail in design of it’s roadsides. Much of the native forest covering is retained, preservation of the wetlands areas and protection of the natural drainage pattern lead to the final landscaping design. These LID techniques help to reduce the volume of stormwater, manage heavy water run-off and replenish other waterways. It also enhances the boulevard and creates an aesthetically pleasing driving experience. <br />
  3. 3. Design Concepts<br />Existing<br />The existing road is bordered on the east by ditches of varying depth from 2’ to 3’. The easement just east of the ditches are overgrown with mature trees, weeds, native grasses and seasonal wildflowers.<br />Independence Parkway<br />Proposed<br /><ul><li>Maintain existing mature trees
  4. 4. Rain gardens and grass swales as bioretention elements for storm water management
  5. 5. Green walls designed of hog wire and metal poles
  6. 6. Existing banners relocated to short columns
  7. 7. Lighting is provided by solar panels mounted on green wall
  8. 8. Dry stacked retaining walls allow the ditch to be widened.</li></ul>Tidal Road<br />
  9. 9. Design Concepts<br />Existing<br />Existing two lane roadway of 28’-0” is constructed of crushed limestone with asphalt top. Shoulders bordering the roadway span 8’-0” are of the same construction composition as the roadway.<br />Proposed design includes maintaining the existing road, constructing two southbound lanes, Grasscrete median and permeable paver shoulder.<br />Proposed<br />
  10. 10. Design Concepts<br />Existing Monument<br />The existing marker is in need of enhancement to provide recognition deserving of such historical landmark.<br />The monument pull-off was designed to encourage passers-by to pause and experience Harris County’s history. <br />A tranquil mini-park area is achieved with a circular permeable pavers pattern surrounding the monument and decorative stone poles bordering the rear. Each sides of the monument is flanked with rain gardens.<br />Proposed Monument Pull-off<br />
  11. 11. Design Concepts<br />Existing Roadside Banners<br />Entrance to San Jacinto Monument<br />The San Jacinto Monument entrance provided inspiration for the short columns serving as part of the decorative border lining this roadway corridor. The existing roadside banners are relocated to top off the short columns and are attached to solar powered light fixtures.<br />Relocate Banners<br />
  12. 12. Design Concepts<br />Monument Plan<br />Monument Elevation<br />The existing historical marker is presently obscure and uninviting. We propose to enhance this point of interest with a permeable paver pull-off, a circular paver pattern surrounding the marker and a mini-park environment. Rain gardens on both the north and south sides of the marker help to create a tranquil setting.<br />
  13. 13. Design Concepts<br />Independence Parkway Easement Elevation<br />The “green wall” designed of metal poles and hog wire. Vines are used to provide coverage along the hog wire creating a green wall. This application creates a similar coverage of bushes without the required trimming to achieve a manicured look.<br />Butting the green wall are short columns with a profile inspired by the San Jacinto Monument. The columns are topped with solar powered light poles. The existing Precinct 2 banners were relocated to the light poles. A Harris County emblem is flanked by round pipes that are attached to the inside of the short columns.<br />These combined elements create a unique corridor along Independence Parkway and provides a relief to motorists and an enhance driving experience.<br />
  14. 14. Design Concepts<br />We envision an opportunity for a bike path that is a part of the State Park routes to Independence Parkway at strategic points.<br />Bike Trail Elevation<br />
  15. 15. Design Concepts<br />Proposed Roadway Perspective<br />As a major cost savings measure we chose the maintain the existing roadway and construct a new median and south bound lanes. <br />The new roadway is constructed of porous asphalt topping which allows water to flow down through the asphalt. The inside lanes run-off flows to the Grasscrete median and the outside lanes flow to the permeable pavers and into the rain gardens.<br />Existing Road Perspective<br />
  16. 16. Road Sections<br />
  17. 17. Hydrographs<br />The two comparative provides hydrologic analysisof the stormwater drainage flows as it relates to this road project of 14.54 acres. The hydrographs to the right indicate our design reduces downstream stormwater runoff and flooding impact at the site.<br />The proposed road is designed with porous asphalt and crushed limestone, permeable paver shoulders and a Grasscrete median. This proposed design will capture and convey stormwater to the roadside rain gardens and grass swales. <br />
  18. 18. Hydrographs<br />HEC-HMS software is used in our office and therefore was utilized to create this hydrological data. The post development hydrograph indicates the peak flows are below the pre-development hydrographs for the 5yr,10 yr and 100 yr storm events. <br />The same parameters and calculation method (SCS Method) from the published output file to develop the Comparative Existing Model was utilized and reflects a flow reduction.<br />5-Year Storm Event<br />10-Year Storm Event<br />100-Year Storm Event<br />
  19. 19. Porous Asphalt Road <br /> “It’s not just for parking lots anymore”<br />Porous asphalt offers a powerful solution in roadway storm-water management.<br />In this case porous asphalt is proposed as a topping on the existing road as well as the new road sections. Porous asphalt will provide water retention benefits including reduced run-off, filtering of run-off and diversion of run-off into rain gardens along the roadway sides. Selection of porous asphalt reduces impervious surfaces of the roadway.<br />In contrast on conventional concrete surfaces rainwater is trap on the surface and requires costly stormwater drainage systems. Rainwater therefore becomes runoff which may contribute to flooding. Also, contaminants are washed from surfaces directly into waterways without undergoing filtration.<br />For these reasons, managing water run-off is a significant issue in roadway planning and development. Porous asphalt can serve to mitigate the impact on the built environment and natural hydrology. Porous asphalt roadways will allow for road design and construction that are more harmonious with natural processes, and sustainable. They conserve water, reduce runoff, promote infiltration which cleanses stormwater, replenish aquifers, and protect streams. Porous asphalt is a combined road and drainage infrastructure, without the cost of drain pipes.<br />Cost<br />Porous pavement does not cost more than conventional pavement. On a yard-by-yard basis, the asphalt cost is approximately the same as the cost of conventional asphalt. The cost difference is generally offset by the significant reduction in stormwater pipes and inlets. When the cost savings provided by eliminating the detention basin are considered, porous asphalt is an economically sound choice. <br />
  20. 20. Permeable Paver Shoulders<br />Permeable Pavers<br />Permeable pavers are consist of concrete pavers with joints filled with very small stones. Water flows through the spaces between the pavers and continue to flow through to the crushed stone layers. The open spaces between the crushed stones store water and infiltrate it to the soil sub-grade. The stones in the joints provide 100% surface permeability and the base filters stormwater and reduces pollutants.<br />Permeable pavers meet best management practice performance criteria as a structural application for roads and pedestrian surfaces.<br />Rain runoff is reduced by as much as 100% and eliminates surface puddles and flooding. The permeable pavers chosen here have a 50 year life-cycle.<br />Permeable pavers as the shoulder material provide aesthetic, draining and structural qualities alongside the porous asphalt road.<br />Examples of permeable paver shoulder<br />
  21. 21. GrassCrete Median<br />GrassCrete <br />GrassCrete provides a natural wetlands environment that works to decrease the impervious surface of this roadway design. Water flow will be contained within the stem height of the grass cover. As a consequence, the flow rate is likely to be limited by grass. GrassCrete provides long established benefits in the ability to balance hydrostatic pressures. This is particularly important in the rapid lowering of water levels where residual pressure in the sub-grade could otherwise cause buckling.<br />The conical profile of GRASSCRETE enables significant volumes of water to be retained within the surface while at the same time providing an effective venting of the sub-grade.<br />Most important stormwater drainage is eliminated with this surface stabilization system.<br />
  22. 22. Rain Gardens <br />Rain gardens offers natural filtration of rainwater run-off …<br />Rain gardens are implemented as part of our design to promote rainwater runoff from the porous asphalt roadway to be filtered and absorbed in a natural setting . Rain gardens reduces rain runoff by allowing stormwater to soak into the ground (as opposed to flowing into storm drains) and surface waters which causes erosion, water pollution, flooding, and diminished groundwater. These gardens help to cut down on the amount of pollution reaching other waterways.<br />By installing a rain garden in selected areas, the “V” channel can be widened at the gardens to provide for a place to “park” runoff from a rain event in bio-retention areas. The dry stacked retaining walls on the west face at the R.O.W. allow the ditch section bottom to be widened to create the wetlands. The dry stacked limestone allows for drainage from behind the wall in addition to providing for scenic relief along the swale ditch. By placing the wetland areas in contact with the limestone we can allow the pH of the water to normalize from any acidity that accumulates in the roadway drainage. Limestone when placed in a wet environment grows lichens and algae that give it a green color that further enhances the presentation.<br /> Native plants are used to reduce maintenance cost and the native plants will better tolerant the water, soil and climate conditions. The selection of ”Native Texas” (hyperlink needed) wetland edge vegetation, such as wildflowers, long grasses, short grasses will absorb most of the water that flows to the rain gardens. Water filters through soil layers before entering the groundwater system. Natural infiltration is achieved through the root systems and through amended soils.<br />
  23. 23. Bio-filtration Concepts<br />Plant Entrance<br />By combining the rain gardens with the grass lined swales, we anticipate that greater than 90% of TSS and VSS will be removed by the grass lined swale ditches alone. Grass lined swales are evaluated to remove as much as 90% of TSS and when used in combination with settling areas or in this case rain gardens, we can infer that nearly all TSS and VSS will be removed. Additionally, grass lined swales will remove between 80% and 90% of metals, nitrates and phosphorous. When these swales have long runs as is the case in this project, much of the bacteria is removed also as a result of exposure to sunlight and heat. <br /> <br />The riffles used in conjunction with the proposed Floatables Screens will filter floatable trash and litter and will aerate the water to entrain oxygen into the runoff. This aeration in conjunction with the settling qualities of the rain garden wetlands and the grass lined swales will provide a drainage effluent that is nearly free of TSS and VSS in addition to being aerated and free of trash and litter.<br />Three proposed rain gardens are proposed for the western face of the grass lined swale ditch for the Independence Parkway. These rain gardens are in the deeper ditch sections at the southern boundary of the project limits.<br /> <br />Dry stacked retaining walls on the west face at the R.O.W. allow the ditch section bottom to be widened to create the wetlands. The dry stacked limestone allows for drainage from behind the wall in addition to providing for scenic relief along the swale ditch. By placing the wetland areas in contact with the limestone we can allow the pH of the water to normalize from any acidity that accumulates in the roadway drainage. Limestone when placed in a wet environment grows lichens and algae that give it a green color that further enhances the presentation.<br /> <br />The rain gardens will retain water most of the time except for very dry periods. The wet characteristics of the gardens will encourage shore birds and wildlife, further enhancing the biological characteristics of the treatment.<br />
  24. 24. Flower Mix<br />
  25. 25. Grass Mix<br />
  26. 26. Project Cost Estimates and Comparison to the Project Costs if Traditionally Developed<br />LID ROADWAY CONSTRUCTION COST <br />Excavation, demolition of roadway and haul off debris $ 180,000.00 New fill material for roadway $ 637,000.00 Grass paver section at median $ 160,000.00 Pervious Pavers $ 250,000.00 Concrete drives and tie ins $ 70,000.00 Underground storm drain, tie ins, catch basins at 200&apos; o.c. $ 260,000.00 w/drain line in center of road under pavers <br />Limestone retaining walls $ 291,000.00 Porous asphalt paving $ 425,000.00 Demolition and removal of temp. drives on West $ 20,000.00 Ditch re-grading $ 80,000.00 Misc. items (swpp, striping, permitting, bonding, etc.) $ 160,000.00 Finish grading with grass, sod, and plantings $ 115,000.00 Contingency $ 250,000.00 Total Estimate $ 2,998,000.00<br />TYPICAL PRECINCT 2 ROADWAY CONSTRUCTION COST <br />1 Mile Roadway with side ditches $5,000,000.00*<br />*as provided by competition sponsors<br />
  27. 27. Thank You<br />Green Road Design Challenge<br />

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