Total Hydrology Planning: Using Water to Drive Community Design

Are you interested in reducing the cost of water infrastructure in your developments and for your homes? Would you like to use less land for stormwater management? Does a lack of water in your area or local water quality issues dictate how and if you can build? If you answered "yes" — or even "maybe" — to any of these questions, consider utilizing total hydrology planning for your next project. Total hydrology planning is a methodology developed by landscape architecture firm Consilium Design to identify and utilize all water resources on a project site. It uses strategies best suited to the relationship between the climate and site-specific conditions of a project to achieve a balance between a site's water supply and demand. Such projects are better positioned to be more resilient to drought and storm events. Planning and Design New efficiencies over traditional water infrastructure can be accomplished through innovative land planning at the beginning of the development process:

• Reducing the development footprint of neighborhoods and communities reduces the linear foot runs of water, sanitary sewer and the developed flows, enabling designers to scale down stormwater management systems and the amount of irrigated landscape.
• More efficient patterns and connectivity of streets allow for more frequent internal looping of the system to better balance water pressure, and reduce line sizes and construction phasing.
• Other site design techniques that reduce water needs include clustering homes around common "front yards" for gathering and play, only using turf for small outdoor living areas (if at all) and using synthetic turf for outdoor play spaces.

Native Landscape Preservation The most water efficient, sustainable landscape for any land is the predevelopment, native landscape. There are several ways to preserve the native landscape and restore disturbed areas:

• Compact design allows for the preservation of larger, consolidated landscape areas that are easier to protect and preserve during construction.
• Native/naturalized landscapes are easier to re-establish in disturbed areas without the need for permanent irrigation.
• Irrigated turf grass areas should be restricted to active-use landscapes such as entertainment spaces and play areas.
• Managing stormwater at its source where it meets the ground, with green infrastructure such as bio-swales, can eliminate or reduce the size of the structured storm system, improve stormwater quality and reduce the need for supplemental irrigation.

Rainwater Usage and Collection Rainwater harvesting can reduce potable water demand in the landscape by 30% or more. There are several techniques that can be applied at the home, neighborhood and community level, including:

• Rooftop collection and storage; and
• Directing surface rainwater as sheet flows or via curb cuts from streets, parking lots, patios and walks to adjacent landscape areas whenever possible.

Changing the Culture of Water Shifting the conversation from water scarcity (i.e., what we don’t have) to water management (i.e., maximizing what is available) can help builders to create solutions in any climate. The shift requires understanding and acceptance of new ideas and approaches to how everyone values and uses water. Working with water providers and other organizations that manage and regulate the distribution and use of water to change codes and policies to allow for new, innovative practices to be implemented can enable the total hydrology planning methodology to be successful. This post was adapted from an article by NAHB Environmental Issues Committee member and Principal and Founder of Consilium Design Craig Karn that first appeared in the June 2020 issue of the Colorado Real Estate Journal. For more information about NAHB’s sustainable and green building programs, explore the green resources on NAHB's website. And to stay current on the high-performance residential building sector, follow NAHB's Sustainability and Green Building team on Twitter.