There is a lot of attention in stormwater management lately. It’s a hot topic because cities are focused on long-term sustainability and looking to reduce runoff pollution, thus motivating property developers, architects, and homeowners to do their part by installing management and treatment systems on their properties. But what’s the difference between detention, infiltration, harvesting or retention? And what are some of the most common ways you can manage stormwater on your property?
Detention and Infiltration vs. Harvesting and Retention
You may be familiar with stormwater detention, but not up to speed on the differences between detention and harvesting. It’s important to understand these processes in order to make an informed decision on how to manage your site’s stormwater.
Large or small stormwater detention systems are often used in conjunction with infiltration. They are used for a set period of time before treated or controlled flows are released into a natural watercourse. This process can help reduce flooding by allowing water levels in creeks and rivers to drop before they overflow their banks during heavy rainfall events.
Stormwater harvesting refers to the collection, filtration, and storage of rainwater for reuse; either onsite (e.g., landscape irrigation) or offsite. A variety of technologies are used for harvesting rainwater including cisterns made from concrete tanks or precast storage vaults.
Stormwater Management: Detention
Detention revolves around collecting water and storing it for later use. This can be done by designing and building engineered underground storage vaults, retention basins or ponds. These areas hold water during heavy rains for volume control and prevent overflow into streets or areas where it could cause damage. They’re also useful for storing stormwater which can be used during dry periods for irrigation purposes.
Stormwater Management: Infiltration
Infiltration involves letting stormwater seep into soil mimicking a more natural process of recharging the earth’s groundwater, rivers, lakes and aquifers rather than collecting it or simply redirecting the runoff.
Stormwater infiltration is the process of water entering the soil. It occurs naturally, but it can also be enhanced by man-made structures like concrete vaults built with infiltration galleries. Infiltration helps manage stormwater, as it reduces runoff volumes and regulates the rate at which run off enters streams, rivers, lakes and groundwater supplies.
Aside from managing stormwater, infiltration is important for flood mitigation because it reduces streambank erosion during heavy rains or snowmelts when high stream flows erode banks and cause flooding downstream. Additionally, infiltration also has filtration benefits, allowing pollutants to settle out before they enter local waterways.
Infiltration isn’t always a straightforward option for managing stormwater in all areas. Urban areas tend to have impermeable surfaces that prevent water from sinking into the ground through infiltration (concrete sidewalks or parking lots). However there are specialized designed storage vault systems that can meet urban challenges and maximize land-use for successful infiltration. Santa Fe Water Systems has years of experience addressing these challenges with a collection of solutions and endless design options that offer a wide range of concrete or HDPE piping specifically designed to accommodate pre-filtration, catchment, and the dissipation into groundwater.
Another traditional stormwater management solution that is growing in popularity with municipalities and property owners is the Dry Well. Our Dry Well can be installed in challenging soil structures to improve water infiltration, including areas with denser surface soils and hard-to-permeate surface substrates such as clay or rock; and where conventional stormwater management methods may not be efficient or feasible.
Stormwater Management: Harvesting
Stormwater harvesting is a surface water management technique that collects and stores rainwater on site, rather than allowing it to discharge into municipal storm drain systems. This can reduce the amount of stormwater runoff and pollution entering nearby waterways.
Harvesting or stormwater retention, involves capturing rainwater before it reaches the ground through many of the same methods as detention. This is another way to store water for the future and prevent problems associated with increased runoff during heavy rain.
Santa Fe Water Systems offers retention vessels that include IAPMO certified steel, HDPE, reinforced concrete, or fiberglass options. We can also design and employ an array of standard or custom systems to meet your site’s harvesting needs:
- Pre-Filtration Units
- Rainwater Storage Vessels
- Pump Station & Controls
- Integrated Irrigation Systems
- NSF Certified Filtration or Treatment
- System Water Replenishment
When it comes to stormwater management, there are many options available. The ultimate goal is to reintroduce clean stormwater back into the natural watercourse, so the most effective method is usually a combination of several options. Some of the most proven stormwater management methods developed to accomplish this include detention and retention systems, as well as infiltration galleries and bioretention. In the end, it all comes down to what works best for your particular site conditions and needs.