Low Impact Development (LID) Principals and Stormwater Management

Stormwater runoff is a continual and growing concern that pertains to both environmental and public health interests.

Due to the penetrating nature of the problem public advocacy and official legislation have had to work in harmony to create an effective mitigation campaign.

One such governing standard is illustrated in the Clean Water Act. Established in 1972, this law illustrates in clear and sweeping terms the standards for tolerable pollutant levels, as well as overall water quality.

There is, in fact, a range of mitigation methods at work ,but among them, Low Impact Development (or LID) practices are regarded as an effective means of handling the problem.

As the name suggests, LID is a developmental plan that emphasizes low impact design infrastructure to protect against stormwater runoff.

There is a variety of ways in which this can be orchestrated. Today we look at several LID principles that are having a real impact on stormwater runoff.

Designing for Low-Impact Development

The idea behind LID is to create a sustainable green infrastructure for handling environmental concerns. As a result, the design elements at work are always made to be effective but also inconsequential in terms of environmental impact.

When working at its best, a Low-Impact Development design is made to serve as an organic water filter of sorts, taking in toxic water, and turning it into something that is of natural benefit to wildlife and humans alike.

In fact, to the naked eye, most LID designs are indistinguishable from ordinary landscaping features.

There are several basic processes that go into a LID design. They are as follows: pretreatment, filtration, infiltration, and storage and reuse.


The pretreatment element of the process involves preparing the site and getting ready for the project at large.

Different environments require different LID solutions. For example, a city cape environment might utilize a larger mitigation feature, such as a bioretention swale.

Similarly smaller environments might require a basin or rain garden.

Other factors, such as the nature of the site can also have an impact. For instance, gas stations, or other areas with deeply contaminated water supplies may require special accommodations or media resources.


The filtration is a core element of the LID process. During this phase of interaction with the runoff, water is filtered through low-impact landscaping features that naturally treat and clean it.

There are a variety of ways in which this end goal is attained, sand, swales, basins to name a few. But one common element of every approach is bioretention soil.

This ingredients used in the process include a special mix of sand and clay that is able to both extract impurities and allow foliage to grow.

Storage And Reuse

When the water has been filtered and naturally treated, it is then stored within the LID feature, and redistributed for practical use such as fostering natural plant growth.

Remember that one of the key principles of LID is that water is a valuable resource, and this is the part of the design process that really embodies that idea.

Though simple in terms of appearance, these features are highly effective at tasks big and small and have been successfully used to remove heavy metal from urban areas, making them proven means of solving major environmental concerns.

Five principles of low-impact development

There are five basic principles involved in low-impact development that help to keep environmental consequences as low as possible. They are as follows.

  1. Conserve Natural Areas Wherever Possible: The main idea is always to keep things natural. For example, if you don’t need to pave every inch of a given space, you shouldn’t.
  2. Minimize the Developmental Impact on Hydrology: Hydrology is, ostensibly anything pertaining to the natural flow of water. While the idea of LID is to treat stormwater runoff, it’s also to have as small an impact on the environment as possible. This means minimizing the developmental impact on hydrology.
  3. Maintain Runoff Rate and Duration from the Site: This means keeping water within the site so as not to serve as a widespread contaminant.
  4. Scatter Integrated Management Practices (IMPs) Throughout Your Site: Integrated management practices capture, store and keep runoff as close to the initial source as possible.
  5. Implement Pollution Prevention, Proper Maintenance and Public Education Programs: While natural designs can mitigate contaminate problems, education is what might ultimately solve them.

Informing the community of how stormwater runoff impacts them, and what they can do about it is the best way to prevent problems down the road.

The State Water Board partnership in the state of California is a good example of an educational initiative. Partnering with universities and other government and public entities to spread information, this effort has proven effective in spreading technical information and tools to help address complicated environmental problems.

Benefits of LID

LID practices are widely appreciated for their benefits. One of the major pros of LID design systems is that they have a low impact on wildlife.

As illustrated above, one of the main ideas of a low impact design is to disrupt as little as possible. Done right, LID projects mean less unnecessary unnatural surfaces and more of nature at its finest. Rain gardens (part of bioretention strategies everywhere) take the problem of rainwater runoff and create a beautiful solution.

This was seen to great effect at the University of Maryland, where rain gardens were used to handle runoff from a half-acre parking lot.

A study published by Dr. Allen Davis from the University illustrates the positive impact that the gardens had over the course of an extended rainy season. The study found an overall reduction in pollutants in the rain events that were documented.


Any LID / bioretention strategy relies heavily on high-quality media. The effectiveness of bioretention soil will ultimately be the difference between success and failure, which is exactly why we take pride in our product.

Contact us for a free quote so that you can do your project the right way.

Norcal Ag Service