Deficiency Breakdown: Flooding

By Jason Abert, Vice President, Service Delivery

Rushing waters moving at a high velocity or cities completely underwater are images that may come to mind when you think of flooding. However, flooding occurs when water collects within typically dry areas. Flooding can be considered pooling in your parking lot or a small area on your property, any place that water collects where it shouldn’t be can be classified as flooding. Characteristically flooding is a sign that filtration or stormwater systems are not working as designed.

How does Stormwater Impact Flooding?

Stormwater runoff is created when precipitation falls on impervious surfaces and does not allow the water to soak into the soil, vegetation or other porous materials. Instead, the displaced water flows over parking lots, roofs and other man-made structures until it reaches a low-lying area where it can collect on a porous surface. The more impervious surfaces a site has, the larger the volume of stormwater runoff it creates. According to the Environmental Protection Agency (EPA), the presence of impervious surfaces in urban areas makes one city block generate more than five times the amount of runoff than a wooded area of the same size.

When water is unable to infiltrate, it flows over the path of least resistance. This path is supposed to direct runoff into stormwater systems that can collect, treat, redirect and safely release water to a more desired location downstream. The most common cause of localized property flooding is mismanaged stormwater systems. If these systems are undersized based on stormwater runoff volume, clogged with debris, have damaged piping or other system impairments, stormwater runoff is redirected to less than ideal locations including parking lots and the lower levels of buildings.

Where and When does Flooding Occur?

Warm Climate Flooding

In warm climates, flooding most often occurs during the rainy season. The most common failures that lead to flooding in warm weather climates are clogged catch basins, cracked piping and mismanaged vegetation that prevents stormwater systems from controlling the large and continual rain events that are common throughout the rainy season. If your property suffers from reoccurring flooding during rain events, establishing pre-season cleanings and a comprehensive preventative maintenance plan can help prepare systems for the incoming influx of water. If flooding continues with preventative maintenance, schedule a consultation and learn if retrofits are appropriate for your site.

Cold Climate Flooding

In cold climates, spring snowmelt is the most common cause of flooding. Snowmelt occurs in early spring when warm weather begins melting the collections of fallen snow that have accumulated throughout the winter. Snowmelt puts a unique strain on stormwater systems, harboring large collections of pollutants including oils, trash, sediment, and debris from the months of accumulation, compaction and movement. Every time snow is collected in a pile through shoveling, snow plowing or even kicking, the concentration of pollutants increases. Once this highly condensed mixture of snow and pollutants begins to melt, stormwater systems are bombarded of the months of gathered debris. This can lead to clogged catch basins, pipes and other system failures that may cause flooding. Understanding how to properly manage snow, preventative maintenance and proactive system cleanings can prepare stormwater systems for the influx of runoff and debris that snowmelt brings.

Impacts of Flooding

Property Damage

Water pooling in undesired locations can lead to flooded basements, cracked concrete structures, eroded banks and dangerous parking lots. If compromised systems do not receive the corrective maintenance and repairs required, sites may be impacted by consistent reoccurring flooding issues.

Sinkholes

Sinkholes are a dangerous consequence of mismanaged stormwater systems, posing a risk to local communities, passersby and local watersheds. Typically caused by a collapsed pipe or subsurface erosion, sinkholes are an urgent matter that must be addressed swiftly and with the utmost caution. Even a sinkhole with seemingly small surface exposure could be connected to a larger, dangerous underground cavern.

Notice of Violation 

Notices of Violation (NOVs) are costly corrective orders and fines that are issued to sites that fail to meet compliance standards. Notices of Violation are issued by local municipalities after scheduled municipal inspections, unplanned inspections or if a complaint was issued to the regulatory body. Establishing a preventative maintenance plan mitigates NOVs by ensuring regulatory measures continue to be met. If an NOV is issued, contact us immediately as these matters are time-sensitive. Failure to complete NOV corrections within the allotted time can result in daily fines.

Safety Risk 

Flooding is a safety risk to your customers, employees and passersby. Flooded parking lots put users at risk of car damage, hydroplaning and increases fall risk. If mismanaged water makes it into a building, there is the risk of slipping, electrocution and future mold on top of property damages. If your property has flooded once before, it is likely to happen again unless preventative measures are taken.

How Do Stormwater Systems Prevent Flooding?

Stormwater systems are designed to collect, manage, treat, and safely release the stormwater runoff a site generates. When properly engineered and maintained, these systems mitigate flooding risks by removing water from impervious surfaces and releasing the stormwater downstream. These site-specific systems are designed based on site criteria, property owner preferences, regulatory requirements and potential stormwater credit opportunities. Systems can be built above or below ground, address water quantity and quality, or even mimic the natural hydrology of a site with green stormwater infrastructure to minimize human impact on the water cycle. Without stormwater systems, runoff would have nowhere to flow and extreme flooding would become a persistent issue.

Catch Basin Cleanings

Prevalent throughout parking lots and down streets, catch basins are often the first stormwater system access point that runoff reaches. This makes catch basins at increased risk of clogging because large trash and debris have not been removed. Sediment, leaves, oil, trash and other pollutants commonly collect overtop of grates or within the catch basin itself. Without cleanings, grates, catch basins and pipes will become clogged with pollutants and lead to system failure, backups and flooding on your property. Catch basin cleanings are recommended annually at a minimum, with biannual cleanings preferred, but site-specific characteristics may increase the frequency. Vactor and Jetting services are recommended to clean catch basins because the use of pressurized water can dislodge compact accumulation more effectively and deeper within systems than traditional mechanical cleanings.

Interested in learning more on property and parking lot flooding? Check out our free educational webinar Mitigating Property and Parking Lot Flooding. This webinar reviews your responsibilities, breaks down different stormwater components that assist in managing stormwater runoff and assess real-life case studies where property flooding impacted businesses from poorly maintained stormwater systems.

If your property has faced flooding in the past, contact us to learn how our certified stormwater experts can protect your property from future flooding with preventative maintenance, repairs and retrofits.