Pete V. Domenici U.S. Courthouse Landscape Retrofit

Challenge

When considering stormwater management strategies for the landscape retrofit, the design team had to work within several unique constraints. The project was initiated over concerns that the existing water-intensive landscape was beginning to cause water-related damage to the parking structure located underneath. A primary goal of the landscape retrofit was to design a landscape that would reduce the possibility of water damage in the future. Additionally, the design team had to work within New Mexico state regulations controlling the distribution of the water. In New Mexico, distribution and access to water are managed to ensure the downstream release of all surface and groundwater. Both of these constraints led the design team to rule out stormwater strategies that relied on retaining and infiltrating water on-site.

Solution

Instead, the design team explored strategies focused on slowing and moving water through the site. For example, the large terraced garden at the front of the courthouse is actually a series of micro-basins. As water moves from one to the other, water is slowed and small amounts are absorbed by the landscape. In areas where it was difficult to change existing grades, such as the parking lot, the design team installed trench drains to collect and direct stormwater to nearby landscape areas. Fortunately, New Mexico state regulations only apply to stormwater that falls on the site, so it was permissible for the design team to capture rainwater that falls on the roof of the courthouse. Runoff from the roof is collected in two underground cisterns and used for landscape irrigation.

• The stormwater management system includes three major installations  to slow and move water through the site: a series of trench drains that release to rock-lined bioswales in the parking lot, trench drains that direct water from the entry plaza to the rock garden designed for stormwater detention, and a series of terraced gardens that slowly direct water through the south edge of the site.
• Irrigation water is supplemented by rainwater collected from the one-acre roof and stored in two underground rainwater cisterns. Together, the cisterns have a total capacity of 16,000 gallons. The cisterns are tied into the drip irrigation system and used to water the drought-tolerant landscape.
• The hardscape materials palette includes 23,240 sf (32%) of materials with a solar reflectance index (SRI) value greater than 29. At maturity, trees will provide shade for 31,033 sf  or 43% of hardscape surfaces.
• Power for the landscape is provided by a 27.5-kWh solar panel array installed on the lower levels of the courthouse roof.
• The plant palette is made up of 58% native plants. The 18 native species include Sunset Hyssop, Mescal Agave, Mormon Tea, Apache Plume, Modesto Ash, Red Yucca, Pineleaf Penstemon, and Soaptree Yucca.
• 87 established Honey Locust and Sycamore trees were preserved in their existing locations. The design team worked with an arborist to provide monitoring and recommendations, such as limiting soil compaction, for preserving tree health throughout construction.
• A variety of topdress materials were used to create a dynamic pattern in the landscape while providing a mulch to retain moisture in the soil. The selected materials included two types of inorganic rock mulch and pecan shell mulch sourced from farms located in New Mexico.
• Building materials and plants were salvaged for reuse in the landscape renovation, including over 80 trees, irrigation pipe, concrete, and structural foam fill. The replacement value of the salvaged materials was roughly 25% of the total materials cost for the project.
• Over 21,000 sf of existing concrete pavement was harvested from the site and reused to create a series of site walls and benches. The 532 linear feet of site walls were constructed from concrete blocks created by saw cutting existing concrete into modular units. 
• Over 40% of the materials utilized for the project were sourced from within 500 miles of the site.
• An existing stone art piece created by artist Doug Hyde and installed by the Art in Architecture Program was relocated, with the permission of the artist, to fit within the renovated landscape design.
• 3% of parking is reserved as preferred parking for Green Score Rated reduced emissions vehicles, encouraging the use of low-emission and high-fuel efficiency vehicles for commuting.
• The project paid the local prevailing wage to the 45 construction workers who worked on the project in accordance with the Davis-Bacon Act. According to the Living Wage Calculator, 58% of these workers earned a living wage to support a family of four.

• The design incorporates 1,796 sf of recycled concrete site walls. Had the design team utilized a standard concrete site wall, the cost would have been approximately $152,550. The approximate cost of the recycled concrete walls was $102,000. Utilizing the recycled material diverted waste from the landfill, created site walls with a premium finish, and saved approximately $50,550.

• One of the primary design strategies for the landscape retrofit was to utilize the site as a “quarry” by harvesting existing concrete paving. This strategy helped to divert over 21,000 sf of concrete from the landfill. The design solution uses the existing concrete cut into modules and artfully assembled into site walls. As a relatively unconventional building material, the design team had to first convince the General Services Administration (GSA) that the harvested concrete was the right choice and then convince the contractor that it could be built. The demolition plan specified dimensions for the saw cut blocks that were packed and stored on-site. Based upon the expected quantity of blocks, the team designed a series of site walls and benches that incorporated a mixture of the different concrete colors harvested. An expected loss for damaged blocks was included in their calculations, but expectations were exceeded at around 84% success. During construction, the design team worked closely with the contractor to ensure their comfort with the details. This collaboration resulted in an exemplary use of recycled concrete as a building material that has influenced the local design and construction community to consider new materials.
• The existing landscape of the courthouse featured an art piece by Doug Hyde. Installed as part of the Art in Architecture program, the piece was originally associated with the malfunctioning water features. The project team had to develop a process for relocating the delicate 6,000-pound stones in order to align with the original structure and the new design. Early in the design process the artist gave approval and advice for relocating. During construction an art conservator was brought in to help with actual relocation of the piece. Each block was craned into place over the new footings. Initially, the stones were placed over a block of ice that allowed each stone to be easily adjusted to its exact location. The challenge of utilizing the ice blocks was that each block melted at a different rate requiring another set of adjustments to the location once the ice had completely melted.

Soil Amendments: Grow-Well Brands
Concrete: Duke City Redi Mix
Irrigation: RainBird
Rainwater Cisterns: Xerxes
Lighting: Beta LED, Ghidini, Nora Lighting, Beta Lighting, BK Lighting
Photovoltaic Panels:  SunPower, Sanyo

Project Team

Client: U.S. General Services Administration
Landscape Architect: Rios Clementi Hale Studios 
General Contractor: AIC General Contractor, Inc 
Landscape Contractor: The Hilltop MEP 
Engineer: NSI - Biohabitats 
Structural Engineer: KPFF 
Civil Engineer: NSI- Biohabitats 
Water System Design: NSI-Biohabitats 
Lighting: KGM 
Electrical Engineer: Syska Hennessy 
Arborist: Bryan Suhr 
Waterproofing: Simpson Gumpertz & Heger 
Irrigation Designer & Local Landscape Architect: Surroundings Photovoltaic 
Design Consultant: Positive Energy

Role of the Landscape Architect

Rios Clementi Hale Studios (RCHS) served as lead designer and landscape architect of record. As project prime RCHS led a team of engineers, designers, and client groups from initial concepts to design development, construction documentation and observation, SITES Pilot Project Certification, and on-going monitoring.