Excessive rainfall can cause significant disruption to the urban environments that we live in. Storm drains can struggle to keep up with the constant flow of water, causing streets, sidewalks, and other impermeable areas to overflow. This can cause a number of disruptions to residents in these areas such as:
Water pollution caused by runoff can cause additional long term damage to the environment due to the unhealthy debris that can be carried away by flowing water. Many of our streets have motor oil, gas, road salt, fertilizer, litter, and other debris that are transported by the flowing water. Storm drains can easily be clogged by this debris, causing them to become even less effective at moving excessive water away from urban areas. The more toxic substances like oil, gas, fertilizer, and road salt can have a significant impact on the natural environment and human health as well. Eventually, these substances will get into waterways that we use for enjoyment, economic purposes, and for our basic water supply. This can cause a number of negative outcomes such as:
Groundwater contamination as a result of flooding can have an especially negative impact on the environment. Groundwater is used for a variety of purposes such as agricultural irrigation and human consumption, which could be at risk if contaminated. The movement of water from the land surface into the soil is called infiltration. A number of factors can contribute to the amount of infiltration that happens in a given area, such as:
If the amount of precipitation is greater than the infiltration capacity of an area, runoff will occur. This is generally measured by the amount of rainfall in millimeters per hour. Tools such as a permeameter or ring infiltrometer are commonly used to measure this. You can think of infiltration as the velocity that runoff is absorbed into the soil. More dense types of soil will absorb stormwater at a slower rate. For example, sandy soil will allow for faster infiltration, where soil containing more clay will be slower at infiltration.
Measuring infiltration to determine soil’s water absorption capacity is important for Engineers, hydrologists, and farmers.
Engineers
Farmers
Hydrologists
As we mentioned earlier, gray infrastructure refers to stormwater management infrastructure that is engineered and constructed. You are likely familiar with these types of infrastructure as they are easy to spot on most urban streets.
