Category Archives: Stormwater

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


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


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.


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


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


The second layer of the permeable paver system is compacted.


permeable paver layers


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


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


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


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



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

paver layers

The four layers of the permeable paver system at Lake Atalanta


See the finished permeable pavers at Lake Atalanta:


The permeable paver parking area at Lake Atalanta


Installed permeable paver interlocked together with space for water infiltration


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


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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Why does that water look so dirty?

War Eagle

War Eagle Mill sits in the middle of War Eagle Creek in Northwest Arkansas, December, 2015. Photos: Stuart Covey. Photo obtained from Garrett Lewis on Facebook

Just a few weeks ago Northwest Arkansas became flooded after 10 inches of rain fell across the area.  People flocked up to Beaver Dam for the rare sight of water spilling through the gates while others took the opportunity to capture breathtaking photos such as the one above. One unifying theme in all of the flood waters was mud!

These water bodies, War Eagle, West Fork, the White River, and others, don’t usually appear this muddy to us.  Perhaps since this was an extremely high flood event, we don’t think about mud in water being a problem.  But the mud, or sediment, in water is a problem.  In fact, sediment is considered the number 1 water pollutant in water!

What’s the problem?  It’s just mud!

Sediment knocks two punches into lowering water quality because it is a pollutant and it is also a carrier of pollutants.  Sediment as a pollutant can cause harm to aquatic life including fish and macroinvertebrates.  It can get caught in the gills of these animals, smother their habitat and breeding areas, and reduce the availability of food.  Water bodies with high levels of sediment may have higher temperatures due to increased absorption of sunlight.  It also costs more to take sediment out of surface water that is treated for drinking water.  For example, on Monday, December 28, 2015, near the peak of the flood, the Beaver Water District extracted 136 tons of mud or sediment from the water it treated. That’s about six times more than the usual 22 tons!

As a pollutant carrier, sediment can deliver increased nutrients, bacteria, and chemicals to waterways.  Those pollutants can adsorb or attach to sediment particles.  Once those sediment particles are detached from the surface of the earth, anything attached to them goes along for the ride, often ending up in the nearest waterway.  For example nutrients found in fertilizers, wastes and manures, and some cleaners, will get into the water after being attached to a soil particle!

While natural erosion produces nearly 30 percent of the total sediment load in the United States, accelerated erosion from human use of land accounts for the remaining 70 percent of sediment that goes to our surface waters!  Sediment pollution causes up to $16 billion in environmental damage annually.

Our friends at the University of Arkansas Cooperative Extension Service provided this short video to demonstrate some ways that sediment and anything attached to sediment can get into our surface waters.




Photo Credit: University of Arizona

Turbidity is a measure of the amount of suspended sediment and visible particles in a sample of water, or essentially, turbidity measures the cloudiness of the water. So clear water has low turbidity (beaker on the left) and water with high turbidity is more opaque (beaker on the right).  We want our waters to stay clear in order to keep ourselves healthy, our aquatic life healthy, and our water healthy!


What can you do to keep our waters clear and mud free?


Build a Buffer – Avoid mowing within 10 to 25 feet from the edge of a stream or creek. This will create a safe buffer zone that will help minimize erosion and naturally filter stormwater runoff that may contain sediment.



Sweep, Don’t Spray!  Sweep sidewalks and driveways instead of hosing them off. Washing these areas results in sediment and other pollutants running off into streams, rivers and lakes.

Use Best Management Practices:  The most concentrated sediment releases come from construction activities, including relatively minor home-building projects such as room additions and swimming pools.  If you are engaged in a construction project, be sure to identify and implement appropriate best management practices to reduce runoff and increase water infiltration.  The Arkansas Forestry Commission has some great recommendations for BMPs to use when doing even small construction projects on your own property at

No dirt in water or the streets!  Notify local officials when you see sediment entering streets or streams near a commercial construction site.  Sediment should never be flowing off of a construction site, nor should it be tracked into the street.

Cover up the bare spots!  Bare soil is endangered soil!  Protect your soil and property by covering up bare spots.  Use weed-free mulch when reseeding bare spots on your lawn, and use a straw erosion control blanket if restarting or tilling a lawn  In gardens, put compost or weed-free mulch on your garden to help keep soil from washing away.

Wash the car on the grass!  Wash your car at a commercial car wash or on a surface that absorbs water, such as grass or gravel.  Washing the car on a hard surface sends dirt, chemicals, and cleaners straight to the nearest waterway!



You can help keep our waters clear and healthy!


Rainwater Harvesting Demonstration Project

By: Angela Danovi

Program Director of Beaver LakeSmart

In mid-October I had the opportunity to attend the EPA region 6 stormwater conference in Hot Springs, Arkansas.  Over the past few years Hot Springs has become a leader in water quality and stormwater management in Arkansas. They have developed a Hot Springs stormwater inspector certification course and require stormwater inspectors to be directly involved with construction projects from planning through implementation and completion to ensure water quality protection and compliance with stormwater laws is a priority throughout the project.  Additionally, they have been implementing various stormwater demonstration projects to reduce runoff and flooding and to provide examples to residents and homeowners with ideas on how they can voluntarily protect water quality on their own property.  (Visit the Hot Springs Stormwater Management Website).

The EPA Region 6 Stormwater Conference provided a great opportunity to visit Hot Springs and see some of their demonstration projects as well as discuss some of the current trends and issues in stormwater management. The first day I decided to attend an all day workshop led by Brad Lancaster of the Watershed Management Group, where we learned about some innovative approaches to capturing and harvesting stormwater.  As a resident of Arizona, Brad has had the opportunity to test various systems and approaches in one of the driest climates in the nation.  For this workshop, the attendees helped to install a rainwater harvesting garden near downtown Hot Springs.  The great thing about this project was that with some help from the city to secure and prepare the site along with a few volunteers and some relatively low-cost materials, we were able to install a rainwater harvesting garden that extended the length of a block in one afternoon!

The project involved installing a rainwater harvesting garden that was situated between a curb and a sidewalk at the bottom of a hill near downtown Hot Springs.  At the top of the site on the upslope, a curb cut was installed and a rock pool was laid out.  The plan is for water that is flowing down the street to enter into the curb cut and flow into the rock pool.  If trash, debris, or cigarette butts is being carried downhill by the water, it should drop out in the pool, limiting the post-storm cleanup and maintenance.

Photo 1: The rainwater harvesting site prepared by the city of Hot Springs looking downhill


Rainwater Harvesting site in Hot Springs inserted into a curb and prepared by the city. The site is situated near the bottom of a hill with the slope heading towards the intersection seen in the distance at the top of the photo.

As the water flows downhill in the rainwater harvesting garden, it will flow through a series of rock checks that will help to slow it down and spread it out.  The rock checks work like stair steps.

Photo 2: The rainwater harvesting site prepared by the city of Hot Springs, looking uphill


The rainwater harvesting site installed in the city of Hot Springs, looking uphill. The water will enter into the curb cut and flow downhill through the site, spreading out, and soaking in.

Photo 3: Laying out stones for the rock checks in the rainwater harvest garden


Brad Lancaster, workshop leader from the Stormwater Management Group, explains installing the rock checks for the stormwater harvesting workshop at the 2015 EPA region 6 stormwater conference

Photo 4: Measuring height from bottom of the swale to the top of the first rock check


Brad Lancaster demonstrates the use of a water level to measure the difference in height from the bottom of the swale to the top of the first rock check

Photo 5: Measuring height from bottom of the swale to the top of the first rock check


Brad Lancaster and a volunteer demonstrate the use of a water level to measure the difference in height from the bottom of the swale to the top of the first rock check

Brad used a water level, a device made with two yard sticks, tubing, and water in the tubing, to demonstrate how to measure the difference in height from the swale to the first rock check.

Photo 6: Volunteers install the rock checks throughout the project


Photo 7: Installed rock check in the water harvesting project


Photo 8: Plants for the rainwater harvesting project


Plants organized by water tolerance to be planted into the rainwater harvesting project

Several different types of plants were planted in the project.  Before planting, the plants were set throughout the site according to their drought tolerance or water needs.  The plants with the highest water needs that could tolerate longer periods of saturation were placed in the center of the site.  Plants with moderate water needs were placed about 2/3 of the way up the slope from the edge of the curb or sidewalk.  The most drought tolerant plants with the least water needs were placed closest to the curb.  Additionally sages were planted in front of and behind the rock checks to slow down water and allow it to spread out throughout the site.

 Photo 9: Volunteers lay out plants according to drought tolerance


Volunteers laying out plants and planting plants according to water tolerance in the rainwater harvesting project

Photo 10: Planting sages near the rock check


Evan Teague, Environmental Specialist of the Arkansas Farm Bureau, assists with planting plants in the rainwater harvesting project

Photo 11: Completed Rainwater Harvesting Project


Brad Lancaster checks the completed site and makes a few adjustments to the rock checks

Photo 12: completed rainwater harvesting project in Hot Springs


Completed rainwater harvesting project in Hot Springs

Installation of the rainwater harvesting project was completed in about three hours by a team of approximately 20 volunteers who were attendees to the EPA region 6 stormwater conference.  One adjustment Brad recommended upon completion of this project was in preparing future projects to not cut out dips in the site preparation because the main idea is for water to flow over rock check as it moves downhill through the site.  He expects this site to still function well, especially as the plants grow and fill in across the site.  A similar rainwater project was planned and prepared around the corner from this one.  As the city of Hot Springs continues to develop and redevelopment occurs in the older sections of the city, these projects will help to protect water quality and improve the quality of stormwater throughout Hot Springs.



Stormwater Runoff – What does that look like?

By: Angela Danovi, Beaver LakeSmart Coordinator

Have you ever taken the time to step outside during a rain event and see where the stormwater on your property flows?  It’s a good exercise to do because you learn about the direction water flows, where water concentrates on your property, and where your water converges with your neighbors or enters a storm drain.  This information is helpful because if you want to implement Best Management Practices to protect water quality, you need to know where the water flows that you are dealing with and where you might get the best impact and water protection.

During the recent rain event as Tropical Depression Bill came over Northwest Arkansas, I took the opportunity to follow the flow of water at my apartment complex and record what was happening.  The purpose was to see how the water was flowing and document it to share as an example for property owners.  There was nothing legally improper at my apartment complex, but there are certainly opportunities to decrease runoff, improve infiltration, and have an overall improvement on water quality.   I hope this blog will show you some things to look for when you walk around your property and evaluate it for possibilities to implement best management practices.

Photo 1: A rainwater downspout from a house

This is a typical setup of a downspout.  Water from the roof is sent on a downspout and out onto the ground.  The force of the water had pushed the black piping at the bottom off of the end of the downspout and the gravel has started washing away with the water.  The water coming off the roof here, goes into the gravel and quickly onto an impervious side walk where it quickly picks up speed and converges with other water water already flowing across the impervious walkway as it heads towards the curb and the nearest storm drain.

20150618_192647A water friendly alternative to downspouts releasing water onto gravel or impervious areas is a installing a rain barrel, installing rain gardens, or even directing the flow to a grassy area.


Photo 2: Rainwater flowing onto an impervious walkway:

Walkways are nice in our yards because they connect our driveways, parking areas, and other areas that we may readily access back to our homes.  However, impervious walkways serve as a conduit for quickly moving rainwater to the nearest creek or stream, bypassing infiltration that is critical for reducing flooding and improving water quality.

20150618_190953[1]A water friendly alternative to impervious walkways that connect to homes or driveways is to disconnect the impervious surfaces.  Can you install a stone walkway with gravel or grass in between the stones?  Can you install grass pavers?  Is there some place you might be able to disconnect your impervious walkway from the adjoining impervious surface?  There’s no right answer for everyone on this issue.  But learn about some permeable alternatives to a traditional concrete drive.  They can improve the aesthetics of the front of your home and will make you be a water smart homeowner!



Photos 3 & 4: Water flowing through backyards

This is the result of water flowing overland, concentrating, and heading to the nearest stream.  This water was flowing through backyards.  This situation occurs because water becomes concentrated and starts flowing overland quickly, rather than soaking in.  This picture is taken just before it drops underground and into a stream that was channelized and put under the parking lot.  The water collected from the parking flows into a storm drain at this location and all of the water flows underground in a channelized stream.



20150618_191429The situation occurs even in grassy areas because this water did not have an opportunity to infiltrate.  Downspouts, impervious surfaces, and poorly contoured yards concentrate water and cause it to flow off quickly.  If this water had the opportunity to infiltrate, you would not have this dramatic of a runoff situation.  If you have rills or small valleys on your property, you might choose to leave the grass higher in those areas.  That will increase infiltration and slow down runoff.


Photo 5: Water flowing into the Storm Drain

Water the flows into the storm drain comes from rain water that flowed overland and was directed to the stormdrain.  Curbs effectively channelize water, increasing its runoff.

20150618_191409A water smart alternative to curbs is to remove curbs.  Water will have a wider area to flow and will not become confined against the curb.  Also, you want to find ways to slow down and divert stormwater before it gets to the storm drain.  If you have a drain on your property, is there a place to install a raingarden before the water gets to the storm drain?


These are just a few photos to show you some of the things you are looking for when you evaluate your home for opportunities to reduce runoff and increase infiltration.  The next time you have a nice rain, go ahead and take a walk!  It’s fun and you can learn more about how water is acting and flowing on your property.  I suggest taking photos so that you can remember what you saw and you can use them when planning any best management projects.  Protecting our water resources starts with you!  Together we can make a difference at protecting our water resources now and for the future.