Last year, I started a new job at a company that employs several landscape architects and landscape designers. I quickly discovered that although landscape architects receive training that is somewhat similar to civil engineering, they view the built world in a very different way. Where I am currently employed, specifically, people value permaculture and seek to incorporate permaculture principles into our clients’ projects. The term “permaculture” is not widely used in the civil engineering/stormwater world. However, I have learned that permaculture and LID are connected. The following blog post briefly describes how engineers can incorporate permaculture principles into their stormwater designs.
What is permaculture?
As previously mentioned, permaculture is not something that is commonly discussed in the stormwater world. For this reason, the following section will briefly describe the permaculture design approach.
The term “permaculture” was coined by ethnobotanists Bill Mollison and David Holmgren in the 1970s as a combination of the words “permanent” and “agriculture.” The movement was a response to the extreme environmental damage in Australia. Bill Mollison was a university professor, and David Holmgren was his graduate student. In 1978, the two published “Permaculture One.”
Today, permaculture is associated with gardening and farming. In reality, permaculture is really a design approach rather than a set of “rules.” Permaculture is actually associated with optimizing the design of human environments, in general. This means that permaculture can be applied effectively to the design of stormwater best management practices (BMPs) and low-impact development (LID).
Permaculture is often associated with gardening, growing food, and farming because it is a holistic design approach that puts a lot of emphasis on mimicking the natural world. Many involved in the sustainability movement design environmental solutions for the purpose of minimizing human impacts. In contrast, the purpose of permaculture design is to be regenerative and fit in with the human environment.
Although permaculture is more than just gardening and farming, most permaculture courses will discuss landscape design and growing food. However, you will also learn about various design principles such as patterning, energy management, building soil, and managing water. These fundamentals will be applied differently depending on your geographic location.
Permaculture Ethics
The three principle ethics in permaculture are as follows:
- Care of the Earth
- Care of People
- Fair Share
The first ethic (Care of the Earth) acknowledges that the Earth provides us the things that we need to survive. For this reason, it is important to care for all living (e.g., plants and animals) and non-living (e.g., land, water, air) things of the Earth because ecology has shown us that the living and non-living systems on Earth are connected and dependent on each other.
The second ethic (Care of People) addresses the physical and psychological needs of people. Humans are social creatures and crave community. As such, permaculture design principles emphasize fostering community and positive human interaction.
The third ethic (Fair Share) involves returning the surplus to the Earth and other people. Because natural resources are finite in nature, permaculture does not value the over-consumption of “junk.” Over-consumption results in an injured ecosystem and an inequitable allocation of resources.
What is low impact development (LID)?
The term “low impact development” refers to systems that mimic natural processes to promote groundwater recharge and enhance water quality. According to the United States Environmental Protection Agency (EPA), “LID practices aim to preserve, restore and create green space using soils, vegetation, and rainwater harvest techniques.” In this way, LID is a design approach that can be applied to land development projects for the purpose of restoring a watershed’s natural hydrology.
Restoring a watershed’s natural hydrology improves the health of our nation’s streams and minimizes soil erosion, which in turn, improves soil health. The goal of traditional stormwater management is to get urban runoff offsite as quickly as possible by conveying it through pipes and channels. In contrast, the goal of LID is to slow down the flow of urban runoff and treat stormwater with the use of biological materials (plants, mulch, and soil).
Some examples of LID include:
- bioretention cells,
- vegetated filter strips,
- permeable pavement,
- rainwater harvesting (cisterns), and
- curb cuts.
These practices tend to be much more aesthetically pleasing than traditional stormwater practices.
Although the term LID is often associated with structural stormwater BMPs, nonstructural stormwater BMPs are just as important. Some examples of these practices include pollution prevention, good housekeeping, and street sweeping.
The connection between permaculture and LID
Permaculture and LID are both concerned with the care of the Earth. LID specifically applies to the care of the Earth in the context of land development. While some LID projects incorporate recreational elements into the design, most LID work is not concerned with the care of people.
Permaculture and LID are also similar in that the fundamental design principles will be applied differently depending on where you are in the world. For example, a rainwater harvesting cistern in a very cold climate will need to be designed differently than a rainwater harvesting cistern in a temperate climate. Similarly, infiltration practices (permeable pavement, bioretention) will need to be designed differently depending on how well the soil drains.
Permaculture teachers often discuss building soils by applying mulch and compost. LID design is also concerned with building soils, specifically for the purpose of increasing soil infiltration. Thus, soil amendments are added to the soil to increase porosity and promote infiltration. In some cases, compost may be discouraged in stormwater LID design. This is because compost contains nutrients (nitrogen and phosphorus) that could adversely impact streams impaired by those pollutants.
Rainwater harvesting and water retention are of paramount importance in permaculture and LID. Unlike “traditional” stormwater management, which seeks to convey water offsite, LID and permaculture practices seek to keep stormwater onsite. This water can either be stored in tanks for later use (e.g., irrigation or flushing toilets). Alternatively, water can infiltrate into the soil for the purpose of recharging groundwater aquifers.
The following table summarizes the similarities and differences between permaculture and LID.
| Description | LID | Permaculture |
| Concerned with the environment/ Earth | Yes | Yes |
| Concerned with developing community | Optional | Yes |
| Primary Function | Capture and treat stormwater runoff | Generate productive human/ecosystem interrelationships |
| Water Management | A primary focus | |
| Soil Management | Mulch is used to cover soil in some stormwater BMP designs. Soil amendments are often proprietary. | |
| Energy Management | Not considered in most cases | A primary focus |
| Food production | Not common | A primary focus |
| Economic benefit | Indirect economic benefit of improved water quality and minimizes the need for expensive piping. | Direct economic benefit from growing food and offsetting reliance on municipal water supply and power. |
| Aesthetics | Sometimes natural but often has a “landscaped” look. | Tend to have a natural look rather than a manicured landscaped look. |
| Level of maintenance | Depends on the design | Depends on the design |
| Use of local/ native materials | It is becoming more common to incorporate native/climate-appropriate plants into LID designs | A primary focus |
How to incorporate permaculture principles into your stormwater design
This section lists some ways you can incorporate permaculture principles into real stormwater designs.
- If possible, make your stormwater designs more interactive and less “boring.” Interactive stormwater BMP designs provide an opportunity to educate the public about the importance of hydrating watersheds and being good stewards of our water resources. In an era of “megadroughts,” this is of the utmost importance. An interesting stormwater BMP is also more likely to be maintained properly. Check out Stacy Levy’s work if you are looking for some inspiration.
- Grading and piping are important, but stormwater BMPs will not work well if you do not select the proper plants. When possible, use native/climate-appropriate plants in your stormwater BMPs to increase the chance of their survival. Native plants also tend to have a more natural look/aesthetic as opposed to an overly-manicured landscaped appearance.
- Why not use captured stormwater to grow food? There are many people around the world who rely on rainwater harvesting for their drinking water and growing food. Captured stormwater could be used to water a community garden or food forest. This makes stormwater BMPs multi-functional and builds resilience within the local community.
- Apply mulch to vegetated areas within stormwater BMPs. Mulch builds soil as it breaks down into organic matter (which increases soil porosity, which in turn, promotes infiltration). In addition, mulch holds moisture in the soil and decreases the temperature of the soil surface. These processes minimize the chance of the plants in your BMP dying.