Month: November 2025

Dry Swales

Dry Swales

Dry Swales

11/12/2025

“How do we categorize water quality swales that are dry for most of the time?”

Water quality swales treat stormwater runoff using vegetated open channels. Not all of these interventions are designed the same. Some are dry for most of the time, giving them the name Dry Swales. Dry swales have specifically selected, highly permeable soil, an underdrain system, and surrounding check dams. Dry swales provide strong performance for metals and nitrate removal, but have higher costs from using highly permeable soils and underdrain systems.

Image credit: https://aqualisco.com/

Water Quality Swales

Water Quality Swales

Water Quality Swales

11/11/25

“How can we treat stormwater runoff using vegetated open channels?”

Stormwater runoff can carry pollution into nearby water bodies. Government bodies may require building and construction operators to slow down and treat stormwater pollution loads coming from their properties. So what’s one way people can accomplish this without using a complicated system? Well, we know that vegetation naturally slows down water and absorbs pollutants while providing infiltration potential. We also know that directing water through a channel allows people to manage the direction of flow. So what if we were to create landscaped vegetation channels that can slow down water, allowing for sediments to settle, infiltration to occur, and pollutants/nutrients to get trapped? Well, this is the basis for Water Quality Swales. Water quality swale slopes are typically at a gentle 3 feet horizontal by 1 foot vertical slope to avoid quick channel flow and maximize surface area for filtration. Land-use managers should install water quality swales before impervious surfaces to enable proper infiltration.

Image credit: https://megamanual.geosyntec.com/

Hyperion Sewage Treatment Plant

Hyperion Sewage Treatment Plant

Hyperion Sewage Treatment Plant

11/10/25

“What is the largest sewage treatment plant in the western US, and what makes it special?”

The US has thousands of sewage treatment plants. The largest one west of the Mississippi, the Hyperion Sewage Treatment Plant, has many interesting properties. Located in the Los Angeles suburb of El Segundo, the Hyperion sewage treatment plant can treat nearly a half a billion gallons per day and recycles nearly 30 percent of its treated water for non-potable uses. The City of Los Angeles is working to make the Hyperion plant recycle 100 percent of its wastewater for beneficial reuse by 2035, including 174 million gallons per day of purified recycled water. These measures will help Los Angeles thrive in the drought-afflicted climate paradigm of the near future. The Hyperion sewage treatment plant is looking to add membrane bioreactor, reverse osmosis, and UV light disinfection capabilities to its processes.

Image credit: https://www.waterandwastewater.com/

Sole Source Aquifers

Sole Source Aquifers

Sole Source Aquifers

11/09/25

“How does the U.S. designate an aquifer that’s the only or principal source of drinking water?”

Municipalities in the U.S. use a plethora of different sources for drinking water, from groundwater aquifers to coastal desalination plants. But some communities rely on a single aquifer for their only or principal source of drinking water. If this aquifer gets contaminated, then it could spell huge trouble for the community. To protect themselves, communities can apply to the EPA to have their aquifer designated as a Sole Source Aquifer if they receive 50 percent or more of their water from a single aquifer and have no reasonable alternative sources if the aquifer becomes contaminated. Sole source aquifer designation provides legal benefits for communities such as extra environmental review for projects that may damage the aquifer, increasing public awareness, and open up potential federal grants.

No Net Increase

No Net Increase

No Net Increase

11/08/25

“How do we ensure new developments don’t increase the amount of hazardous substances in a body of water?”

People generally don’t want a water body to become more polluted, especially if it already has many hazards. Consequently, environmental regulators work to prevent more toxins from entering sewer systems using No Net Increase rules. No net increase regulations state that any development must not increase the amount of pollutants entering the water body of release. Infrastructure and construction operators must undertake best management practices to satisfy no net increase rules. One approach is to remove as much pollution as you discharge.

Stormwater Retention vs Detention

Stormwater Retention vs Detention

Stormwater Retention vs Detention

11/07/25

“What is the difference between stormwater detention and retention?”

Many modern stormwater guides recommend that infrastructure operators and property owners use retention and detention to control runoff. Even though these two actions rhyme, they have very different functions. Stormwater retention permanently holds stormwater, typically through plants, while stormwater detention temporarily stores runoff with physical mechanisms. This is the difference between Stormwater Retention vs Detention. Runoff is typically preferred by infrastructure regulators since it keeps stormwater from flooding areas later.

Embankments

Embankments

Embankments

11/06/25

“What’s the structure that holds canals in place?”

Canals are the lifeblood of societies all over the world. These waterways provide passageway for cargo while controlling water levels. But what structure keeps canals in place? Well, elevated trapezoidal structures parallel to the canals called Embankments constrain the movement of water outwards. Protecting embankments is core to keeping communities safe all over the world.

Why New York City’s Gowanus Canal is So Polluted

Why New York City’s Gowanus Canal is So Polluted

Why New York City’s Gowanus Canal is So Polluted

11/05/25

“Why is the Gowanus Canal so polluted?”

The Gowanus Canal has been a fixture of Brooklyn for the past 150 years. Built as a major industrial transportation route, the body of water was subject to decades of pollution from surrounding coal yards, tanneries, machine shops, and many other types of industrial activity. The canal’s design prevented regular movement between the more oxygenated water in New York Harbor and the deoxygenated water in the canal, leading to a filthy, pathogen-infested environment. People also used the Gowanus Canal to carry out illegal dumping activities. Combined sewer overflow events dump raw sewage into the canal during heavy rainstorms. When we look at these reasons together, it’s easy to see Why New York City’s Gowanus Canal is So Polluted.

Image credit: https://cdn.vox-cdn.com/

Sludge Thickening

Sludge Thickening

Sludge Thickening

11/04/25

“Why do we need to add solids to wastewater before further treatment?”

Sludge treatment processes such as dewatering require conditioning before they can proceed. One of the first steps is to increase the solids concentration of sludge through Sludge Thickening. Sludge thickening ensures that the sludge is not too thin to handle in later processes. 

Image credit: https://aosts.com/