Monthly Archives: April 2016

Permeable Paving Demonstrated at Lake Atalanta

by: Angela Danovi, Program Director of Beaver LakeSmart

Water quality protection, reduced runoff, and aesthetically pleasing public parking are just some of the benefits Ozarks Water Watch has helped to contribute in the current renovation at Lake Atalanta in Rogers.  Over the past several weeks, we have shared photos and information about the permeable paver project.  Today, we are going to share photos and information about how the pavers were installed and the benefits the pavers will provide to the community and to water quality in the Lake Atalanta and Beaver Lake Watershed.

What are Permeable Pavers?

Permeable is a term used to describe paving methods for roads, parking lots, and walkways. A permeable paving system allows water and air to move around the paving material. The permeable pavers that have been placed near the entrance to Lake Atalanta are an interlocking paver.  They look similar to a brick.  However, they have small notches on the side that allows them to interlock with one another while leaving space for rainwater to infiltrate into a layered media that is placed beneath the pavers.  Permeable pavers are different from pervious pavers because water cannot infiltrate through the paver but is instead directed to the edge of the paver where it infiltrates into the ground.  Learn more about the type of permeable pavers installed at Lake Atalanta here.

Bethany Alender from Beaver Watershed Alliance holds a pervious paver during a demonstration installation at Lake Atalanta

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Permeable paver with interlocking notches allows for the pavers to lock together while leaving space for water to pass between pavers and infiltrate into underlying media

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Pallets of Unilock interlocking permeable pavers at the construction site prior to installation.

How are permeable pavers installed?

A permeable paving system generally has three layers of clean gravel.  Each subsequent layer of gravel is smaller than the layer the beneath it.  The interlocking pavers sit on top of the layer of the smallest size gravel.  In some systems small rock is placed between the pavers to maintain space and allow water to infiltrate between the pavers.  For the system at Lake Atalanta, the notches on each paver lock the network of pavers together while leaving space for water to infiltrate between them.

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A base layer of clean and washed gravel is laid as part of the permeable paver system at Lake Atalanta

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The second layer of clean and washed gravel is laid as part of the permeable paver system at Lake Atalanta

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The second layer of the permeable paver system is compacted.

 

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Top layer of clean and washed chipped rock is spread over the permeable paver site.

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The top layer of chipped rock in the permeable paver system is spread and evenly layered.

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The pavers are placed by hand, interlocking each of the notches together and are gently tapped into place.

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Design plan for permeable pavers. The pavers are laid out in a herringbone pattern.

 

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The pavers are placed by hand, interlocking each of the notches together and are gently tapped into place.

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The four layers of the permeable paver system at Lake Atalanta

 

See the finished permeable pavers at Lake Atalanta:

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The permeable paver parking area at Lake Atalanta

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Installed permeable paver interlocked together with space for water infiltration

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Edge of the permeable paver system. The system will be enclosed with curbs on the outer edge and concrete on the inner edge.

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The completed permeable paver project at the entrance to Lake Atalanta

 

Benefits of Permeable Pavers to the Community:

  1. Permeable or pervious pavers allow water to infiltrate back into the ground.  This allows for rainwater to recharge local groundwater supplies, rather than quickly running into nearby creeks or streams.
  2. Permeable pavers reduce flashy runoff during rain storms.  Flash flooding is a result of rain falling on too much impervious surface in a concentrated area during a storm.  With permeable pavers, water can infiltrate into the ground, reducing runoff during rainstorms, reducing high streamflows during storms, and allowing water to slowly percolate, providing more water for streams throughout the year, rather than just during storms.
  3. When reflective, light-colored pavers are used, permeable pavers can be effective in reducing the urban heat island effect. Conventional asphalt absorbs most of the sunlight that strikes it because of its dark color.  That light is converted to heat and radiated back out, contributing to relatively higher temperatures in paved or urban areas.  This is known as a heat island.  By using light colored pavers, more light is reflected and less and is converted into heat, reducing the urban heat island effect.
  4. Due to their design, permeable pavers can provide a safer driving surface in hazardous winter driving conditions.  Unlike conventional asphalt and concrete, which provides a foundation for sheets of ice to develop in winter weather conditions, permeable pavers allow for ice to only form in small sections, providing less continuous surface area for sheet of ice to form, and allowing sunlight to penetrate the ice and melt it quicker.
  5. Permeable pavers protect local water resources.  By reducing runoff and increasing infiltration, permeable pavers also help to reduce pollution.  When a raindrop hits a surface, that raindrop will carry with it sediment and any pollution laying on the earth’s surface, where the raindrop strikes.  By allowing the raindrop to soak into the ground, rather than running to the stream, sediment and pollutants are captured in the ground and cleaner water will slowly release to the stream or percolate into the groundwater.
  6. Permeable pavers reduce thermal pollution in streams.  Thermal pollution is pollution resulting from abnormally hot water entering a waterway.  Hot water discharges to streams can come from many sources including industry.  One of the most common sources of thermal pollution is from asphalt parking lots.  By installing permeable pavers, water that would strike a hot parking lot and runoff, is allowed to soak into the ground, percolate through the soil, and cool to an appropriate temperature before entering a waterway.  By reducing thermal pollution, the habitat of aquatic species is protected.

Benefits of Permeable Pavers to the landowner:

  1. With increased infiltration and runoff reduction, permeable pavers can help reduce costs associated with erosion.  Permeable pavers may even be effective in reducing irrigation to nearby grass or plants.
  2. Permeable pavers are easily replaced.  if one becomes chipped or broken, the individual paver can be lifted out of place and replaced with a new one, extending the overall life and function of pervious paving project for relatively little cost.
  3. Permeable pavers provide an aesthetically pleasing design to any outdoor space.  Due to the versatility in design, they can be placed in any size or shaped area and provide a more pleasing design than concrete would allow.

Thank you to our project partners

The Environmental Protection Agency Region 6, through the Arkansas Natural Resources Commission has provided partial funding for this project under Section 319 of the Clean Water Act.

 

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