Stormwater Solutions

On this page you will find a range of stormwater solutions, from projects as simple as rerouting your downspout to a complex tree box filtration system.

Please note that these are general suggestions and guidelines. It is always best to get input from a professional stormwater engineer or landscape designer with a stormwater background before you start a project. For detailed design guidelines, or if you intend to use any of these suggestions for stormwater credits or permit requirements, please refer to the Stormwater Design Manual published by NC DEQ.

Simple Solutions

Protecting our waterways doesn't have to be hard. Below are some examples of options that are simple to place on any property and are relatively easy to maintain.

Reroute Your Downspout

A downspout that has been turned towards your garden, lawn, rain barrel, or other permeable areas.

Why?

Keeps stormwater from running down your driveway and into local waterways. Each home downspout can drain 12+ gallons of water per minute during a 1-inch rainfall.

How?

Buy a flexible downspout extender from your local home improvement store and turn it away from hard surfaces into a lawn, garden, or other soakable area. You can also connect it to a rain barrel or cistern to collect water for future use.

Benefits

  • Irrigates your lawn or garden
  • Conserves water
  • Gives shellfish a cleaner home
  • Protects rivers, streams, and the ocean

Video

Rain Barrel/Cistern

A barrel or tank that collects and stores rainwater.

Why?

Rain barrels and cisterns(PDF, 342KB) catch rain from roofs and gutters, which prevents pollutants from washing into local waterways. Rain barrels typically hold up to 100 gallons. Cisterns are essentially larger versions of rain barrels. Sizes for cisterns can range from 100 to thousands of gallons!

How?

First stop, shopping! Head to your local rain barrel sale or home improvement store to pick up a rain barrel and a gutter diverter. Second, pick a base for your barrel to stand on. The height helps increase your water pressure. Third, measure the height of your barrel, taking into account the base and the diverter. Fourth, cut your gutter. Fifth, direct your overflow away from your foundation. Finally, attach a hose and enjoy watering your garden or washing your car with reusable water. If you have a cistern, you can even consider placing it underground if you have limited space on your property.

If you have property near Bradley Creek or Hewletts Creek, our HOWBMP program will fully fund and install larger cisterns on your property. Sign up for a site visit to see if you qualify.

Optional: Consider painting your barrel for a fun touch.

Benefits

  • Provides a steady, free source of nutrient and mineral-rich water for your garden or lawn
  • Can decrease flooding
  • Shows your neighbors that you're progressive and environmentally conscious
  • Decreases polluted runoff and protects our waterways

Videos

Rain Garden

A garden specifically designed to soak in polluted stormwater runoff.

Why?

Rain gardens(PDF, 5MB) are dug as a "bowl", rather than a mounded garden bed, and designed with zones in mind – plants that can tolerate wet and dry conditions are placed in the middle, with drought-tolerant plants framing the outside. This design allows more water to collect in the center, slowing it down and giving it time to soak in.

How?

If you have property near Bradley Creek or Hewletts Creek, our HOWBMP program will fully fund and install rain gardens on your property! You can sign up for a site visit to see if you qualify. Otherwise, you can plan it yourself or hire a landscaper that is versed in stormwater management. They will have insight for the best location of the rain garden. Rain gardens require some source of stormwater, like a downspout from a roof, but also need to be a safe distance away from a building's foundation. During planting, native plants are recommended for rain gardens because they don't require pesticides and fertilizers. After that, it’s like regular gardening – prune/deadhead your plants, weed regularly, remove trash and pet waste, add mulch annually, and water during plant establishment and dry periods.

Bonus: Use the water captured in a rain barrel or cistern to water rain garden plants during dry periods.

Benefits

  • Increases property value
  • Can protect against flooding
  • Adds greenery and beauty
  • Provides a unique habitat for pollinators (like bees and butterflies) and wildlife
  • Recharges the groundwater table
  • Filters pollutants and protects our waterways

Videos

Backyard Wetland

Perfect for that soggy patch of yard that won't go away.

Why?

Wetlands collect runoff, filter pollution, and provide lots of habitat for local wildlife and insects, including mosquito predators such as dragonflies. They are typically bigger and deeper than rain gardens, and function more on their own. They are typically more wet than a rain garden. Learn more about constructed wetlands by exploring J.E.L. Wade Park, home of the largest constructed wetland within the City of Wilmington!

How?

If you have property near Bradley Creek or Hewletts Creek, our HOWBMP program will fully fund and install wetlands on your property! You can sign up for a site visit to see if you qualify. Otherwise, you can plan it yourself or hire a landscaper that is versed in stormwater management. They will have insight for the best location of the wetland, but they will typically fit best in a section of property that stays consistently wet. Wetlands will have a similar "bowl" shape to a rain garden to collect water, but can be shaped more flexibly. Once it’s established after a few years, it’s very hands-off. Wetlands are meant to function as their own little habitat.

Bonus: Route your rain barrel or downspout towards your wetland.

Benefits

  • Increases property value
  • Can protect against flooding
  • Adds greenery and beauty
  • Provides a unique habitat for pollinators (like bees and butterflies) and wildlife
  • Recharges the groundwater table
  • Filters pollutants and protects our waterways 

Tree Planting

We sure love trees of green.

Why?

Tree roots hold soil in place to reduce erosion and soak in lots of water when it rains! Not to mention, trees provide habitat for wildlife, improve air quality and they can even boost your mood.

How?

If you have property near Bradley Creek or Hewletts Creek, our HOWBMP program will fully fund and install trees on your property! You can sign up for a site visit to see if you qualify. Or, head over to your local garden store or nursery, pick up some native trees, and plant them on your property using practices recommended by local arborists.

Benefits

  • Increases property value
  • Can help reduce noise from loud neighbors or busy roadways
  • Adds beauty to your yard
  • Improves mental wellness
  • The shade can help save on energy costs
  • Greater tree canopy can buffer high winds
  • Provides habitat for wildlife
  • Helps absorb standing water and stormwater runoff which filters pollutants and protects our waterways.
  • Great for improving air quality

Creative Alternatives

Below, you'll find alternative options to typical property features that can help reduce stormwater and protect our waterways.

Impervious Area Removal

Life is already hard enough.

Why?

Impervious, or hard, surfaces do not allow water to soak in. Roads, sidewalks, and driveways are some examples. When it rains, stormwater runs over these hard surfaces and collects pollutants like bacteria, oil, litter, and gardening chemicals along the way. Converting these hard surfaces to permeable surfaces allows space for rain to soak in and reduces the amount of runoff that can carry pollution down the drain.

How?

Whether you do it yourself, or reach out to local contractors to do the job for you, you can replace pavement from your driveway, parking lot, sidewalk, etc. with grass or permeable materials. You can also reduce your rooftop area. This is a good alternative for low flow parking lots.

Benefits

  • Reduces localized flooding
  • Recharges groundwater table
  • Converting to grass protects naked feet (and dog paws) from burns in the summer
  • Stops pollution from entering waterways

Bioretention Area

Like a bigger rain garden.

Why?

Bioretention areas are often used intermittently with rain gardens. However, the term “bioretention area” is typically used when talking about a larger treatment area than a typical rain garden. Similarly designed to rain gardens, bioretention areas have a shallow depression in the center to capture and soak in stormwater. They are a great alternative to retention ponds because rather than only retaining water, the plants and soils help to soak in and actually filter out pollutants.

How?

If you have property near Bradley Creek or Hewletts Creek, our HOWBMP program will fully fund and install bioretention areas on your property! You can sign up for a site visit to see if you qualify. Otherwise, you can do it yourself if you have the proper digging equipment and permits. You may also look for a landscape professional or engineer that is versed in stormwater management. After that, maintenance is like regular gardening – prune/deadhead your plants, weed regularly, remove trash and pet waste, add mulch annually, and water during plant establishment and dry periods.

Bonus: Direct a rain barrel, cistern, or downspout to the bioretention area.

Benefits

  • Increases property value
  • Can protect against flooding
  • Adds greenery and beauty
  • Provides a unique habitat for pollinators (like bees and butterflies) and wildlife
  • Recharges the groundwater table
  • Filters pollutants and protects our waterways
  • EPA's Bioretention Design Handbook

Grass Swale

A stretch of wide, sloped grass that soaks in stormwater more efficiently than a ditch.

Why?

While ditches are meant to transport water as quickly as possible, grass swales do the opposite – they slow down and allow stormwater to soak into the ground. This reduces the amount of polluted runoff draining into local waterways, while still helping to control flooding on roadways and properties.

How?

Find a stormwater-certified contractor or engineer to help with the design process.

However, here are some things to consider when designing a swale:

  • The swale should be wider than it is deep so the water has a chance to slow down and soak in.
  • Swales should not be used for projects with lots of sediment.
  • You can build small “check dams” or barriers that will slow some of the water as it moves in the swale.

Benefits

  • Very cost-effective – they’re one of the least expensive solutions available, and treat large amounts of stormwater
  • Simple to maintain - just keep it clean and occasionally mow
  • Adds green space to roadways
  • Natural look for landscaped properties
  • Prevents erosion along roadways or paths
  • Slows down and naturally filters stormwater runoff

Level Spreader

Slow and steady wins the race!

Photo Credit: NCSU-BAE

Why?

Rather than allowing stormwater to rapidly flow into local waterways, potentially causing erosion and flash flooding, level spreaders slow down and spread out stormwater. It collects the water into a long channel with a shallow wall. The water then can flow over the shallow wall and spread across a large buffer area before reaching a stream, with a good portion of the water already soaking back into the ground.

How?

Find a stormwater-certified contractor or engineer to help with the design process.

Review the Level Spreader Chapter in NCDEQ's Stormwater Design Manual

Benefits

  • Treats large areas of land
  • Slows down stormwater
  • Reduces erosion
  • Recharges groundwater table
  • Improves water quality

Good for Built Spaces

For areas that have a greater hard surface footprint, here are some clever ways to incorporate stormwater management without taking up a lot of space. Be aware, however, that most of these projects will require a stormwater engineer during the design process.

Filterra Box

No green space? No problem.

Why?

Filterra boxes are a great tool for incorporating trees and stormwater treatment along streets, parking lots, and sidewalks. Since the stormwater is collected and treated below ground, they take up very little space and can be as intricate as desired. They can help meet regulatory requirements for stormwater reductions, and also add aesthetics and trees/greenery in urban areas.

How?

First, plan out your needs and the space you’ll have available. The Filterra boxes are easily customizable and can accomplish several goals at once. The most effective method is to place them strategically around stormdrains to divert runoff before it goes to local creeks. The Filterra website shows lots of options for how you can connect your boxes to underground storage tanks and sedimentation chambers as well.

Benefits

  • Small footprint with high pollutant removal
  • Can reduce flooding
  • Adds additional trees
  • Improves water quality

Permeable Pavement

So many stylish options.

Why?

Replacing hard surfaces with permeable pavement(PDF, 574KB) or other surfaces that water can soak into reduces the amount of runoff and prevents pollution from running into waterways.

How?

There are different types of pervious materials for you to choose from. Select what’s most appropriate for your situation:

  • Pervious concrete or asphalt – good for low flow areas
  • Pervious pavers – great for a simple driveway, sidewalk, or patio project. They can come in concrete or brick.
  • Plastic or concrete grids – awesome for meeting LEED requirements and reinforcing gravel projects.
  • Turf – if you have overflow parking, or only occasional parking, turf is an easy solution
  • Bound Recycled Glass Porous Pavement – Made by FilterPave, this is recycled glass material that adds color to sidewalks or parking lots!

Reach out to local concrete contractors to see if they offer pervious concrete or asphalt. For pavers, check with BMP-certified contractors that may have the supplies available.

More involved projects can also include underground storage and filtration systems that will additionally treat stormwater as it moves through the system.

Please note that pervious materials are not recommended in areas that will receive high sediment inputs. This can clog the pathways for water and will require constant cleaning and maintenance.

Benefits

  • Increases property value
  • Beautifies your property
  • Protects against flooding
  • Reduces stormwater runoff and pollution entering waterways

Underground Storage

If you don’t have space above ground, move it underground.

Why?

Sometimes, there is just not enough space on your property to implement all of the projects you want. But, with smart planning, you can still help improve water quality by incorporating storage tanks below the surface. The storage can be customized based on your needs without taking up valuable space above ground. Stormwater will get collected in tanks that will either connect to another system, discharge to the nearest water body at a very slow rate, or be stored for water reuse. Some pipes will even have holes that will allow the water to soak back into the groundwater table and be filtered naturally.

How?

Find a BMP-certified contractor or engineer to help with the design process.

Keep in mind the needs of your property when comparing types of underground storage devices. To get the best water quality benefits, it is important to include other stormwater solutions in combination with the underground storage.

Benefits

  • Save space above ground
  • Can reduce flooding
  • Reduces stormwater runoff
  • Improves water quality

Green Roof

The sky’s the limit with this option.

Why?

Roofs are an additional source of stormwater runoff, as water cannot soak into the hard surface. Rather than transporting the water to the ground, why not provide some soaking capabilities at the source with a green roof? Not to mention it also provides additional greenery for developed areas.

How?

You can start small by having small collections of planters or turn it into a green oasis. Check with your building codes and engineers first to confirm how much weight is allowed on the roof. Then, consider hiring a landscaper or urban designer to really maximize your space.

Green Roofs Website

Benefits

  • Small footprint
  • Adds additional greenspace
  • Captures stormwater at the source
  • Can reduce flooding
  • Creates a mini oasis to reduce stress
  • Makes the skyline a little greener.
  • Provides habitat for pollinators & birds
  • Improves air quality