Impact of Rain Events on SWPPP

There are a few kinds of natural events that may have an impact on stormwater pollution prevention plans (SWPPP) and related construction site setups, and one of the most common here is a notable rain event in the area. Adding significant water to any construction site may involve a need for various responses to prevent stormwater runoff pollution or other related issues, and this is a key part of these programs.

At Silver Leaf SWPPP, we're here to help Utah clients with a wide range of SWPPP solutions, including everything from plan documentation to dewatering services, street sweeping and more. Here are some basics on how rain events are defined, the important SWPPP-related areas to think about when they happen, and some additional considerations.

Defining Rain Events

One of the first and most important parts of this conversation involves defining rain events in the first place. Generally speaking, any 24-hour period where more than half an inch of rain falls is considered to be a 'notable rain event.'

Notable rain events may lead to an increased risk of pollution-related issues, such as stormwater runoff, potential sedimentation of nearby bodies of water, and more. More on that in just a moment.

Risks Caused (or Exacerbated) by Notable Rain Events

When a rain event takes place on a construction site, a few risks either activate or rise in nature. These include:

• Site erosion: This is the most common risk, as any rain event may cause erosion or sedimentation-related issues on a construction site. The more moisture or water, the more likely it is that erosion will take place. And within SWPPP, erosion is a big issue - it leads to runoff issues, which may in turn lead to pollution and other risks.
• Sedimentation of nearby bodies of water: As mentioned above, this is a key risk as well. If the site doesn't have adequate controls in place, or if they weren't properly inspected during the rain event itself, it's possible that sediment could make its way into nearby bodies of water, which can cause environmental damage.
• Impaired waters: This is another key risk of rain events and construction sites that don't take the proper precautions. If a site doesn't have adequate stormwater runoff control measures in place, it's possible - though certainly not guaranteed - that nearby bodies of water may be impaired as a result.

Drought Increases Rain Event SWPPP Risks

While some might assume that rain events aren't as impactful to SWPPP areas in drought-heavy areas like Utah, the opposite may actually be true. In drier parts of the world, any rain event is cause for greater concern - as it's less common in these areas, and thus must be taken more seriously than in wetter parts of the U.S.

This is because when there's less water in the ecosystem, the impact of pollutants within existing water supplies only grows. This includes any pollutants that may find their way into the water supply as a result of inadequate stormwater control or other SWPPP-related issues.

For this reason, it's essential to ensure that any construction site in Utah is properly protected from potential rain events - and that all SWPPP measures are taken seriously, regardless of past weather patterns.

Important SWPPP Themes to Prevent Rain Event Issues

To ensure that rain events don't cause too much damage or lead to any pollution-related issues, there are a few core SWPPP themes that should be followed. These include:

• Having and maintaining adequate stormwater controls in place at all times: This includes everything from silt fences to erosion control blankets, sediment traps and more. Any of these measures should be inspected and evaluated after any notable rain event, to ensure that they are still in proper working order.
• Conducting soil tests: This step is often overlooked or underappreciated - but it's essential to understand the existing soil composition before any significant rain event takes place. Doing so can help inform which types of stormwater control measures would be most effective for the given site.
• Properly disposing of any materials or debris: Any materials (like concrete, asphalt, etc.) that may have been left on a construction site should be properly disposed of after a rain event - this helps reduce the risk of sedimentation and other pollution-related issues.
• Regular inspections: Regular SWPPP inspections are key for any construction site - but especially so after a rain event. This is another way to help ensure that the existing stormwater control measures are functioning as intended and that no other issues occurred due to the additional moisture or water from the rain.

It's clear that rain events can have a significant impact on SWPPP plans and construction sites, but with the proper preparation and implementation of key SWPPP themes, it's possible to mitigate or even prevent many of these issues altogether. Properly responding to rain events is an essential part of any SWPPP setup - and can help protect local waterways from potential pollution-related risks.

For more here, or to learn about any of our SWPPP solutions for clients around Utah, speak to our team at Silver Leaf SWPPP today.