The botanical garden in Huntsville, Ala., expanded and renovated their west parking lot with a permeable paver upgrade that absorbs and redirects stormwater runoff to new rain gardens in the lot.

The Huntsville Botanical Garden retained 4-Site, a Huntsville, Ala.-based landscape architecture and civil engineering firm, to expand the functionality and available space of a parking lot on the garden's west side. In addition to the increased parking, 4-Site owner and principal Jerry Cargile had to address the lot's need for stormwater infiltration and conveyance, improve the quality of the stormwater runoff, and reuse the water for irrigation purposes.

Two four-man crews installed 17,062 square feet of Pavestone Eco-Prioria pavers in a herringbone pattern in one week after the existing pavement was removed and a layer of aggregate was placed over the expanded parking lot. The stormwater was routed to rain gardens at the end of each parking row via collection points at the head of each parking stall.

Design
The design proposal called for a two-inch layer of open-graded washed stone over the parking lot's stone base. Permeable pavers were placed atop the open-graded stone, creating a medium for the stormwater to flow through and a path for infiltration. The stormwater was routed to new French-drain collection points at the head of each parking stall, and then redirected to rain gardens established at the end of each parking row. The rain gardens provide water quality and temporary storage of the stormwater, until an outlet system allows the water to be directed to the master irrigation pond.

Following the success of the parking lot installation, the botanical garden retained the same design and installation team to renovate the site's front entrance. The same permeable pavers were used for the entryway, including Mocha Blend-colored pavers for the field in a herringbone pattern and a Heritage Buff blend for the borders.

Installation
Brandon Davis, founder of Huntsville-based contractor firm Outdoor Solutions, Inc., oversaw preparation of the site, delivery and grading of additional base material for the parking expansion, installation of the French drains and leveling of the site over a three-week period. Paving Stone of Alabama President Eddie DeSouza worked with Davis and two four-person crews to install the pavers in one week, ensuring the herringbone paver joints were installed in straight lines across the entire parking lot. The crews installed Pavestone's Eco-Priora 5-inch by 10-inch permeable pavers, which have eight concrete lugs on the long side of each block and four lugs on the short side to assist with alignment and structure.

When the west parking lot installation was completed, the botanical garden took on the renovation of the front entrance off of Bob Wallace Avenue. With the success of the west parking garden, the same team was retained to design and construct the new entrance, and the same permeable paver patterns and colors were selected to provide continuity to the pavement and parking areas.