In 2018, Moore Square, which is one of the oldest remaining parks in the center of downtown Raleigh North Carolina, received a major renovation to meet the flourishing growth of downtown residents, businesses and visitors.
The 4-acre park, which is bordered by Raleigh’s signature oak trees, now includes meandering walkways that weave through spacious lawn areas, granite benches and amenities. The large expanses of lawn invite visitors to relax, play, or attend concerts and festivals with capacity for 5,000 attendees. Beneath the lawn areas are utility vaults and storm cisterns essential to the overall function of the park.
A great deal of thought was involved in the soil design for the lawn areas due to its predicted high use – therefore soil compaction, plus the surrounding impervious surfaces of downtown Raleigh in a region that receives large rain events, consecutively at times. Stormwater planning and management were key.
The engineered soil selected was a blend containing ASTM C330 expanded slate coarse sand as the primary component. Expanded slate belongs to the family of expanded shale, clay, and slate (ESCS) structural lightweight aggregates manufactured across the country. ESCS aggregates are porous, inert, adsorbent, and when blended with soil for green infrastructure, provide air-entrained environments for plant roots to thrive. The ESCS porous structure increases and maintains permeability while providing moisture storage for roots when the surrounding soils begin to dry. ESCS is structurally sound therefore the strength and durability of the engineered soil protects root zones from over-compaction for years of use.
The official ribbon cutting ceremony in August 2019 arrived simultaneously with a significant rain event. The ESCS lawns infiltrated, the turf was stable, and soon after the rain ended, the event was a grand success.
