System Components & Structures

When addressing a drainage problem, one of the most important decisions is whether to move water away through a traditional catch basin and pipe system or to manage it on-site using a dry well. Both approaches are widely used and effective when applied in the right context, but selecting the wrong s…

Is a Catch Basin Appropriate Here? Before a catch basin is installed, it is important to step back and ask a simple but often overlooked question, what purpose is it actually going to serve at this location? Catch basins are frequently installed out of habit or because “there has always been o…

Retention and detention ponds are among the most recognizable features of modern stormwater management systems, yet they are often misunderstood or used interchangeably. While both are designed to manage runoff and protect downstream infrastructure, they serve distinct purposes and function in very …

High density polyethylene, commonly referred to as HDPE, has become a widely used material for culvert pipe applications because it is lightweight, corrosion resistant, and relatively easy to install. In roadway and stormwater infrastructure, HDPE culverts are frequently selected as an alternative t…

Open channel outfalls occupy a unique space in stormwater infrastructure. They are simple in appearance, often nothing more than a vegetated swale or gently graded channel, yet when properly designed they function as treatment systems, flow control measures, and in northern climates even snow manage…

Stormwater culverts come in a wide range of materials, and each type carries a unique combination of strength, lifespan, cost, and installation considerations. Choosing the right material is not a one size fits all choice, because every site presents different soil conditions, hydraulic needs, envir…

A well managed stormwater program depends on accurate and complete information about every outfall in a community. Outfalls are the final discharge points where stormwater leaves the municipal system and enters a stream, lake, wetland, or other receiving water. Because these locations represent the …

Constructed wetlands are engineered systems that mimic the natural processes of a real wetland in order to treat stormwater, wastewater, or other polluted runoff. They are intentionally designed and built rather than formed through natural hydrology, but they function in much the same way. Water flo…

Culverts are enclosed conduits that carry surface water beneath roads, railways, trails, and embankments, allowing drainage and traffic to coexist safely. They form one of the most common, and often most overlooked, structures in municipal stormwater networks. When sized, installed, and maintained c…

Every time rain falls on streets and parking lots, it sweeps grit, trash, and pollutants toward the nearest low point. Catch basins sit at those low points, quietly collecting runoff and helping cities keep roadways safe, pipes clear, and receiving waters cleaner. This article explains how catch bas…

What Exactly Is a Precast Underground Vault? A precast vault is a large, reinforced-concrete box or cylinder installed below grade to detain, treat, or both detain and treat stormwater when surface land is scarce. The modules are factory-made for quality control, then craned into an excavated pit an…

What is a stormwater outfall? A stormwater outfall is the point where a storm-drain system, whether pipes, ditches, or channels, discharges runoff to a receiving water such as a stream, wetland, lake, or the ocean. Regulatory guidance clarifies that simple cross-road culverts, which only pass flow b…