How to combine engineered earth armoring with greywater treatment

In recent years, the drive for sustainability has intensified, particularly in sectors where resource conservation is critical. This is especially true in the realm of urban development, where innovative strategies are being deployed to combat the effects of water scarcity exacerbated by frequent droughts. One such strategy is implementing on-site wastewater treatment systems, which are increasingly being adopted in residential and commercial projects. These systems are not only a response to the urgent need for water conservation but also a proactive measure against the growing demand for water resources driven by population growth in several water-scarce regions across the United States, including states like Arizona, California, Florida, Nevada, and Texas.

State and local governments are recognizing the potential of these systems by offering incentives for their use, particularly for the recycling of greywater. Greywater, which comprises lightly used water from bathroom sinks, showers, bathtubs, and clothes washers, excludes wastewater from toilets and is considered safe for reuse in applications such as landscape or crop irrigation. The application of greywater reuse systems is a practical response to the dual challenges of water scarcity and the need for resilient urban planning.

The benefits of reusing greywater are manifold. Firstly, it significantly reduces the demand for freshwater in irrigation and can be efficiently distributed through systems like drip irrigation or spray techniques. These systems are particularly suited to challenging terrains, such as areas with difficult access or steep slopes. The reuse of greywater in such contexts not only supports the establishment of vegetation, which is crucial for erosion control but also enhances groundwater recharge, water quality, and property aesthetics, thereby increasing property values. For instance, a study commissioned by Santa Rosa, California, showed that a laundry-to-landscape greywater system could save about 56.8 l (15 gal) of water per person per day.

Moreover, when greywater systems are combined with technologies like Engineered Earth Armoring Solutions^®, they provide optimal slope stabilization, which is crucial for preventing erosion. This integration has proven successful on various residential and commercial properties, highlighting the potential for widespread application in urban development.

The practical implications of these systems are illustrated by a case study from 2019, where a developer acquired two homes adjacent to each other near Coral Beach in Malibu, California. The properties were plagued by a steep, unvegetated slope that suffered severe erosion due to runoff from the nearby Pacific Coast Highway. The erosion not only threatened the stability of the slope but also led to sediment deposition on the properties' driveway, with potential long-term impacts on the local stormwater system's hydraulic capacity and maintenance costs.

In response, the developer decided to incorporate sustainable practices into the renovation of these homes. This involved installing a drip and spray irrigation system that utilized greywater to irrigate the steep slope behind the houses. Additionally, to protect this investment and further stabilize the slope, an Engineered Earth Armoring Solution was employed. This system is designed to lock soil in place, enhancing the slope's stability and offering protection against further erosion.

The success of this project prompted the City of Malibu and other local municipalities to encourage the adoption of similar integrated solutions involving on-site wastewater treatment and slope stabilization technologies. These initiatives are not only sustainable but also cost-effective compared to traditional hard armoring solutions like rock riprap, which have higher carbon outputs and financial costs.

The adoption of on-site wastewater treatment and Engineered Earth Armoring Solutions represents a shift towards more sustainable urban development practices that effectively address the challenges of water scarcity and land degradation. By integrating these technologies, municipalities can reduce operational and maintenance costs associated with urban water management and promote environmental sustainability. The example set by Malibu can serve as a model for other regions facing similar environmental challenges, underscoring the importance of innovative solutions in contemporary urban planning.

Overall, the movement towards sustainable urban development using on-site wastewater treatment systems and innovative land stabilization technologies not only conserves water resources but also promotes ecological stability, enhances urban aesthetics, and improves property values. As water scarcity becomes an increasingly pressing issue, the role of these technologies will undoubtedly become more critical in shaping resilient urban landscapes across the nation.