Underlying Infrastructure Yields Natural and Enhanced Park Experience
By Christina Hughes and David Lundberg
Prior to the construction of the Clay Family Eastern Glades development in Houston, Texas, Memorial Park, consisting of 1400+ acres, was primarily known as an exercise park where people could engage in outdoor activities such as walking, running, and biking. As Memorial Park developed a new, 10-year Master Plan designed by landscape architectural firm Nelson Byrd Woltz, they sought to increase patronage and greater expand usage of the park. Walter P Moore joined the team to redesign and reconstruct the widely underutilized Eastern Glades section of the park and establish the park as an all-day destination for Houston residents and visitors.
The highlight of the Memorial Park Eastern Glades development is the prominent Hines Lake, which provides many benefits to the site—some hidden to the untrained eye. Eastern Glades was designed to both minimize impacts from development and highlight the importance of conservation and environmental stewardship. Concepts such as water reuse, water treatment, and flood resilience were integral to the project.
In addition to habitat and recreation benefits for the community, the lake was designed as a multi-function basin that stores and treats runoff for re-use as irrigation and holds stormwater runoff during large rainfall events to protect the site and surrounding area from increased flood risk. To address the owner’s concerns for a natural-looking aesthetic, most of the infrastructure is hidden below at least three feet of water in the lake. Above this level, the park will re-use the first foot of water for irrigation in lieu of buying potable water from the City. A water balance study used statistical rainfall analysis and local information on seepage and evaporation to determine the percentage of total irrigation demand that would be met using one foot of water storage. Working with a lake consultant designing the circulation system, it was determined that the lake will be fully refilled with rainfall and stormwater capture from the site most months out of the year.
The water reuse storage is meant to offset the irrigation demands of the Eastern Glades improvements, providing a total of 86 percent of annual irrigation demand and making the park more resilient to drought. Walter P Moore conducted the water balance study to confirm the lake’s capacity to store water to be reused for the park’s irrigation needs, accounting for losses from infiltration, evaporation, and seepage.
The lake also functions as a stormwater quality treatment system and includes two sediment forebays at the lake’s inflow points to restrict sediment and debris particles entering the main body of the lake, which substantially reduces maintenance dredging of the lake. To further promote settling of polluting particulates, a small weir plate on the outlet restricts outflow for the first few inches of ponding, thus slowing the release and increasing the residence time of the “first flush” inflow of stormwater, which generally contains the highest amount of contaminants. The increased residence time promotes sedimentation of pollutant-carrying solids that may be in the stormwater entering into the lake during the beginning of a rainfall event. The result is improved water quality leaving the lake, which ultimately enters one of the city’s major waterways, Buffalo Bayou.
Year-round, the lake is designed to provide an aquatic wildlife habitat, afforded by intentional non-uniform shaping at the base and edges of the lake along with native wetland and riparian planting along the lake edge slopes. The intentionally natural look of the lake was intended to create a habitat for native creatures. Both the outlet restrictor structure and inflow pipes to the lake were designed to be invisible to visitors of the park and provide minimal disturbance to the aquatic habitat.
In addition to preserving a natural environment, Walter P Moore focused on preservation of the existing forestry by saving and working around the existing trees. The project is in the process of achieving SITES Certification, the U.S. Green Building Council designation for sustainable site development.
The wetland planting around the edges of the lake serves an aesthetic purpose and improves water quality as well. In concert with the forebays, the wetland planting is designed to polish the water, limit shoreline erosion, and decrease lake maintenance. The dense vegetation also provides a natural look and feel to the lake’s surroundings to give visitors a sense of being in nature.
Portions of the Eastern Glades area are naturally swamp land, but a goal of the project was to ensure the pedestrian trails do not become inundated with water during a rain event. The original plan for the trails was to raise them above the swampy areas. However, this strategy would block natural drainage patterns. Facilitation of the natural drainage patterns was accomplished by adding small drains at curb breaks and by providing small trenches that allowed water to pass beneath the trails. A total of nearly 30 drains were installed in low spots along some of the outer trails.
Eastern Glades design includes grassy lawn areas for recreation and picnicking interspersed with pockets of naturally planted “island” areas that preserve some of the most significant trees on the site. Native plants are prevalent throughout the project which reduces the need for frequent fertilization, thus limiting the environmental impacts to the waterways. Walter P Moore designed the lawn areas to rapidly drain either by infiltration into the underlying soils or to undisturbed “island” areas where the water can slowly infiltrate. The grading was done in such a way that the grassy areas can be used soon after a rain event without damage to the landscape or inconvenience to visitors.
Walter P Moore used a collaborative approach to improve the safety of visitors around the lake. Although not required by code, the firm referenced a series of different resources to develop a recommendation for safety bench design along the edges of the lake and pedestrian pathways that fit the project. Working in concert with the Nelson Byrd Woltz, the safety benching was creatively incorporated with the wetland planting to accomplish a natural look and feel that was integrated into the surrounding aquatic environment, while providing a less dangerous depth around the edge of the lake. This design further added to the water quality treatment and the lake bank erosion control.
The 100-acre section of Eastern Glades is a gem among outdoor enthusiasts and nature aficionados. While much of Memorial Park remains an athlete’s playground, Eastern Glades invites visitors to take a moment to slow down, take in the beauty of their surroundings, and stay awhile. Meanwhile, the carefully laid infrastructure does its work behind the scenes, keeping the park lush and pedestrian-friendly.
Christina Hughes is a Senior Associate and Water Resources Engineering Team Director. Contact her at email@example.com.
David Lundberg is an Associate and a Senior Engineer in the Civil Engineering group. Contact him at firstname.lastname@example.org.