Water Reuse A Primary Focus of Campus Design

For the past seven years, a significant and central role in my professional work has been occupied by Walmart. I have been directly leading the civil engineering site and infrastructure design of the company’s new 350-acre campus in Bentonville, Arkansas, which is setting a benchmark for future corporate campus design and development. 

The new Walmart Home Office campus, which opened to associates in 2025, was designed to advance Walmart’s vision for sustainability, resilient workplace—one that supports both its associates and the broader Bentonville community while reinforcing a long-term environmental commitment to Northwest Arkansas. 

This outcome was achieved through a series of integrated engineering and planning strategies that reimagined the campus from the ground up. These included regionally sourced materials for mass timber construction, energy-efficient mechanical, electric, and plumbing systems, thousands of trees and plants for landscaping, and several critically important water-related best management practices that incorporate sustainable low impact development (LID). LID is an engineering and land-planning approach that harvests and manages stormwater runoff onsite to replicate predevelopment hydrology and return improved water quality to the community.

Water treatment and reuse was a priority for the campus design as several nations around the globe are currently faced with severe water shortages or are on the brink of water bankruptcy. As defined by the United Nations, water bankruptcy involves the scenario where the water needs of the global population, in concert with climate change-fueled heat and drought, have resulted in more water use than is naturally created in the form of rain and snow. In the U.S., we have seen shrinking rivers and lakes, declining aquifers, and wetlands that are drying up, particularly in the Southwest. 

While the scale may be small, the focus on responsible and sustainable water management incorporated on the Walmart Home Office campus is a steppingstone in the right direction. 

My firm, Walter P Moore, served as the lead civil site and infrastructure engineering design team for the campus since 2018. Over 80 team members from the firm contributed their expertise—including water resources, traffic, and site structural engineering—to the campus’s sustainable design initiatives. These initiatives, including those related to sustainable and resilient LID design, were strategically guided by the landscape architect SWA Group’s concept of Big Nature.

Embracing the Big Nature concept, the idea that every landscape we inhabit, whether developed at a large or small scale, is part of a larger ecological system, we designed the campus civil engineering systems to actively implement water and stormwater management and treatment processes that mimic predevelopment conditions, improve the local ecology, and minimize environmental impact.

We implemented the water-related goals associated with Big Nature by designing a comprehensive, resilient, and sustainable stormwater treatment train that include bioswales, rain gardens, the Razorback Greenway Trail—an open, vegetated hike-and-bike trail and waterway traversing the campus—and the North and South wet-bottom lakes. In concert, each of these treatment features work together to efficiently manage stormwater, filter pollutants, provide non-potable water supply, and improve water quality before discharge to public waterways, including Town Branch Creek and Osage Creek.

LID played a key role in regard to water management for the Walmart Home Office campus. We based our LID designs on ensuring that almost every drop of water that lands on the campus is harvested, treated, and sent to one of two retention ponds to be reused on campus. 

Our design integrated bioswales along major roadways and conveyance paths, which proves effective in attenuating stormwater runoff and reducing infrastructure costs across the campus. By providing storage, attenuating peak flows, and treating developed flows locally before entering the storm sewer system, the bioswales serve as a natural pretreatment mechanism that enhances water quality and contributes to a more sustainable, campus-wide stormwater management strategy.

The stormwater collection systems convey and discharge pretreated runoff to the central Razorback Greenway Trail vegetated waterway. We designed the Razorback Greenway Trail not only as an extension of the hike-and-bike Razorback Trail, but also as the backbone of the campus stormwater conveyance and water-quality treatment systems. The Greenway allows for the connection of multiple stormwater treatments designed to activate, aerate, polish, and deliver naturally treated stormwater free of sediment, excess nutrients, contaminants, and debris to the campus lakes and public streams serving as outfalls.

By organizing and connecting stormwater treatments upstream of the campus lakes, we significantly reduced the need for costly and maintenance-intensive infrastructure such as lake aeration systems, chemical and biological controls to regulate algae blooms, and dredging. 

The two campus lakes were specifically designed to temporarily store and manage stormwater. Their design allows for controlled release of developed flows, prevents downstream flooding, and minimizes impacts on natural waterways such as Town Branch Creek and Osage Creek. The lakes serve as the final treatment step in the campus stormwater treatment train as the wet bottoms and wetland planting filter any water released before discharge.

A major component of the campus master plan was a clear understanding of water as a critical resource. Planning and design for the most effective use of water across the campus was an overarching goal. Our team identified water resources to serve the campus, evaluate risks associated with extremes of too much or too little water, and plan comprehensive water management strategies to better understand the water cycle. 

This allowed us to develop mutually beneficial solutions for the campus, community, ecology and environment. Understanding site-specific water supply sources, demands, and stresses formed the foundation for designing a more resilient and sustainable campus.

We also conducted water mapping and water balance analyses for Walmart’s original home office site to identify feasible options for onsite water collection, storage, and reuse, while also providing critical data to support LID and resiliency strategies on the new campus. These water balance efforts integrated multiple uses of campus water resources into mapping software that guided the design of the sustainable infrastructure.

Because of the broad scope of the water infrastructure design, campus water supply demands can be shifted to non-potable sources, reducing overall water supply costs. By using captured rainfall and building condensate for irrigation and other low-contact maintenance applications, potable water can be conserved for critical uses such as drinking water, food preparation, wellness facilities, hospitality services, and conference centers—ensuring high-quality water is available where it is most needed.

To ensure campus water supply was distributed appropriately, we designed flow diagrams to map the interdependence between water sources and campus demands. These diagrams provided the framework for calculating required storage capacities and strategically positioning processes within the water supply chain. Scenario development further helped determine the best solutions regarding land use, recreation, operational needs, and cost considerations.

We also designed water resource protection measures, including a progressive stormwater management train that transitions from small, distributed features to large, centralized systems before water leaves the campus. The campus accepts and treats stormwater from nearby neighborhoods, with detention centralized in either of the two lakes upstream of each outfall. This approach reduces discharge during extreme rain events and improves downstream drainage conditions.

A non-potable water distribution network captures stormwater runoff and building condensate through storm sewers and bioswales. The network delivers treated water volume from the two lakes on campus into a pressurized distribution system for irrigation and maintenance water, reducing any reliance on the City of Bentonville’s municipal water supply and enhancing water resiliency.

Water balance and mapping played a critical role in the design of the campus lakes, providing insight into water sources and uses to optimize performance and efficiency. 

The master plan prioritizes resource management strategies, including the integration of a weather-actuated gate at the South Lake to optimize water harvesting, reuse, and active detention storage. This intelligent gate dynamically adjusts water levels in real time, ensuring overlap between storage capacity, public discharge, and campus reuse functions.

By facilitating pre-storm peak releases, the system discharges only the volume necessary to accommodate incoming storm events. This proactive approach mitigates downstream flooding, improves stormwater management for surrounding developments, and enhances overall hydrologic resilience.

To support efficient long-term maintenance, we designed bioswales and pass-through planters with minimal landscaping requirements. Strategic planting around the lakes further minimizes debris entry, reinforcing the campus’s sustainability goals.

Overall, our team designed the Walmart Home Office campus master plan as a comprehensive, resilient, and environmentally responsible approach to sustainable water management. 

Despite the smaller scale, the solutions to the global water crisis and the LID engineering concepts incorporated into the Walmart Home Office campus are a prime example of how we can become closer to being self-sufficient in regard to large-scale campus water needs and even give back cleaner water to nearby resources.