Land, water and energy nexus design and development of nature-based urban housing

Panel: 5. A smart new start for sustainable communities

Authors:
Ricardo Amon
Judy Corbett, Independent researcher, USA
Charles Brush, Hydrolytics, USA

Abstract

A Land, Water and Energy Nexus framework is used to understand the design and development of Village Homes in Davis, California. VH was designed in the early 1970’s by progressive thinkers, people who wanted to provide living interactions with natural systems, where almost half of the land area would be dedicated to building a multi-layered landscape, dependent on rainwater to establish and sustain growth, understanding that the optimal capture of rainwater would be critical for sustainability, encouraging plant growth, enhancing soils, and recharging the groundwater basin.

Using micro catchment principles, the landscape is contoured with cross-sloped swales and holding ponds, optimizing the harvesting of rainwater, and minimizing runoff from the system boundary, enhancing the water cycle. Planting open spaces with ornamental plants and trees, fruit trees, vineyards, and vegetable garden areas, creating an edible landscape to produce food, reducing the food loss from converting agricultural land for urban development. Water scarcity conditions continue since 2011, impacting the LWE nexus.

In 2015, the community drilled a well to replace municipal water used for irrigating the landscape. Under water scarcity conditions additional groundwater is used to supplement lower rainfall, increasing the water energy intensity of watering the landscape. Buildings are embedded in the landscape, with contoured swales guiding the distribution of roads and construction sites, to maintain gravity-driven rainwater flows. Building designs fit the landscape, using solar passive building principles, capturing heat, installing extra insulation to walls and ceilings, and transpiration-roofs to limit air conditioning. Smaller lots encouraged smaller foot-print dwellings demanding less thermal and electric energy. The small lots allowed more land to not-be-under-construction, making it available to develop a natural landscape. Creating an essential value to living in the neighborhood, where people would share and benefit from common landscaped areas. Creating a value-added landscape premium.

The VH experience has extended beyond the neighborhood boundary, to influence city planning with progressive concepts, where nature is understood as an important element of designing urban spaces, expanding an understanding of the critical role that nature has in providing sustainability to human endeavors. People participate in community through board of directors, architectural reviews, and landscape committees; creating standards with respect and tolerance, and the willingness to understand each other and regard for the environment. It requires a common understanding among people to promote “nature-based” codes and standards, where the common-good benefits are priority to achieve desired outcomes.

Where the landscape premium of a VH house is reflected in higher real estate values, among comparable houses, providing a longer-term investment strategy, where a present-value can be estimated to reflect the landscape premium’s life-cycle benefits.

The landscape premium includes direct water energy benefits, derived from the micro catchment landscape design, capturing, and retaining rainwater, landscaping with energy sufficiency principles, and reducing the cost of building on-site municipal stormwater discharge systems. Other indirect energy benefits are achieved when less stormwater is discharged on municipal treatment facilities, decreasing electricity demand while lowering the community’s water energy intensity.

The landscape design is unique in its capacity to capture rain to recharge the aquifer. It provides a model where local stakeholders, including water and power utility companies, could create incentives to adopt micro catchment urban housing principles, creating living spaces with edible landscapes recharging local aquifers. But there is a tradeoff when using groundwater for irrigation and the community must be aware to not impact the aquifer.

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