4 Water Runoff Solutions For Parking Lots


Parking lots require proper water runoff solutions to prevent damaged surfaces as well as the contribution to local water pollution. Storm water runoff occurs when water travels across hard surfaces, such as parking lots, roads or roofs. Instead of soaking into the soil and replenishing groundwater sources, as it naturally should, this water ends up in creeks, lakes, or other bodies of water. After rushing over hard surfaces, water becomes contaminated with oil and other pollutants that harm local water sources.

Storm water can include water or snow. Runoff is made possible by impervious surfaces such as parking lots, sidewalks, streets and buildings. You might be surprised to find out how quickly runoff finds its way into streams and other bodies of water. For many years, people thought this was a good thing, until we realized just how much pollution it creates in our local waters.

In the US, “point sources” of pollution, or the use of discharge pipes that lead directly into a water source, are almost entirely banned. That means the main source of water pollution relates to storm water runoff, or nonpoint source pollution. This is a big issue because it pollutes our rivers, streams and other water sources, which isn’t good for you, your family or our communities.   

The worst pollutants that originate from this form of runoff include:

-Oil and emissions from vehicles.

-Brake dust

-Road salt

-Bacteria from animal waste and litter that end up on roadways or other hard surfaces.

How To Outfit Your Parking Lot With Proper Drainage

A great deal of research has gone into identifying the best practices to prevent water runoff from negatively impacting our communities. There are a number of ways you can help improve drainage while preventing runoff.

1. Parking Stall Size

Interestingly, the larger the parking stall size the greater the contribution to excess imperviousness. There are different measurement ranges used to define compact, oversized, handicapped, and on-street parking spots. You don’t necessarily need oversized spots, not even to accommodate large vehicles such as vans or SUVs. According to the Center for Watershed Protection, moderate sized parking spots can accommodate very large vehicles just fine.

Back in 1995, researcher Thomas Schueler estimated that switching out large parking stalls for compact stalls, which are about 30% smaller, could reduce total parking lot impervious areas by 10 to 15%.

2. The Layout Of Your Parking Lot

Water runoff is largely influenced by the layout of your parking lot. The size of parking lot aisles is determined by the use of 1 or 2 way lanes. Aisles must be larger in order to accommodate 2-way traffic. By simply making 1-way aisles with angled parking spots, you can reduce the amount of space needed and subsequently reduce impervious surfaces. By reducing the width of parking aisles from 24 to 18 feet, a parking lot’s impervious cover can be reduced by 5 to 10%.

3. Pavement Options

The toughest pavement materials best suited to heavy traffic are impervious. While you can’t get around using these materials, you can use other materials around your parking lot to help facilitate more natural absorption of water. For instance, slopped parking aisles can channel water towards areas with permeable surfaces, such as grass, gravel or soil. 

4. Planting Greenery

Planting islands of greenery in parking lots can offer ample benefits, including greater control of runoff. In the past, these islands were often built up around the surrounding surfaces. Overtime we have realized that they should be built below the surface level so that water falls inside.

It’s very important to pick plants that prefer to be wet in order for this method to be successful. Planting beds can help detain storm water to a certain degree. For larger storms, an overflow outlet can be added to planting beds, often called bio-retention areas or bioswales.

Let Us Help You Reduce Storm Runoff From Parking Lots & Roadways

There are countless parking lots across the US, all of which have the power to increase or decrease pollution. With proper planning and design you can be a part of the solution as opposed to a part of the problem.

Kleenco Construction works in compliance with all local storm water laws and regulations. We provide cost-effective and environmentally friendly solutions to storm runoff. Our wide range of water management services include:

-Regular inspections

-Testing water quality of collection basins

-Repair damage caused by erosion

-Correct storm water runoff

-Removal of trash & overgrowth

-Hydrant repair or replacement

-Vegetation control

-Blockage removal and repair

-Repair of inlet stations

-Spillway repair

-Maintenance of collection basins

-Repair sewer line on sanitary and storm pipe systems

-Repair inlet stations

-Repair outfall structures and devices

-Water line repair and point connection services

-Leak detection and utility location service

-Provide ground cover such as sod placement, straw coverings and hydro seeding.