What Is a Subsurface Gravel Wetland?

What Is a Subsurface Gravel Wetland?

Subsurface gravel wetlands help remove contaminants naturally.

When it rains, the rainwater falls on the ground or whatever happens to be on the ground: roofs, grass, cars, roads, people, etc. The surface on which rainwater falls is either permeable or impermeable; generally, only certain soil types are permeable. Impermeable surfaces like asphalt and concrete force the water to trickle down wherever gravity takes it. Even rainwater on a lawn can eventually leach onto the sidewalk and down to the nearest storm drain. Storm drains aren’t the only outlet for stormwater though. What is a subsurface gravel wetland, you may ask? Let’s take a brief look and see where Reliable Contracting comes into the picture.

What Is a Subsurface Gravel Wetland?

A subsurface gravel wetland is an alternative wastewater or stormwater treatment system that uses a gravel subsurface cell system to process water and covers less than an acre. The lowest level of the wetland is a series of gravel cells connected by pipes. These gravel pits constantly hold water and are anaerobic, meaning they lack oxygen. 

Above the gravel pits is a layer of wetland soil, and growing in this soil is a thick layer of wetland vegetation. In Maryland, this system is easy to achieve due to the state’s many native wetland species. During a storm, a layer of rainwater will collect above the wetland soil but also drain into the gravel cells. 

The stormwater or wastewater usually starts in a collection basin, such as a sediment forebay, before it flows into the subsurface gravel wetland.

The Success of Subsurface Gravel Wetlands

The first implementation of a subsurface gravel wetland was in 1996, when it was invented purely for wastewater treatment. Over the years, it has gained more ground as it proves to be one of the most successful forms of storm and wastewater treatment. These systems successfully remove concentrates of nitrate and phosphorus and solid wastes. They work well through every season, including winter. Maintenance every three years is critical to continued optimal water filtration.

Subsurface Gravel Wetlands & Other Stormwater Management Systems

Reliable Contracting is a major Anne Arundel County asphalt manufacturer and contractor that also accomplishes concrete paving, utility installations, and stormwater management system installations. Subsurface gravel wetlands are one of the multiple stormwater management systems available in Maryland; are they right for your commercial property?


Reliable is dedicated to delivering quality products, displaying professionalism within the firm, seeking new opportunities for expansion and profitability, and providing an environment for individual success. If you have a commercial or residential construction project that you need taken care of, please contact Anne Arundel County’s largest site-work contractor today by calling 410-987-0313 or visiting our website. You can also follow Reliable Contracting on Facebook, LinkedIn, Pinterest, and Twitter!

Reliable Contracting Company serves the following and surrounding counties: Annapolis, Queen Anne’s, Anne Arundel, Baltimore, Baltimore City, Calvert, Caroline, Charles, Howard, Prince George, St. Mary’s, Talbot, and Washington D.C.

This entry was posted on Friday, April 28th, 2023 at 1:23 pm. Both comments and pings are currently closed.