Solving The Water Runoff Puzzle With: Interlocking Permeable Pavers

Part of a $10 million improvement campaign underway at The College School of Webster Groves (Mo.), a parking lot installation of interlocking, permeable

Part of a $10 million improvement campaign underway at The College School of Webster Groves (Mo.), a parking lot installation of interlocking, permeable concrete pavers provides students a lesson in ÎgreenÌ construction and environmental responsibility. Key to the project’s overall goal is using low-impact, energy- and water-efficient design and building materials.

Masonry market leader Kirchner Block & Brick supplied the Eco-Stone permeable concrete pavement system for Phase 1 of The College School renovation. Notes David Mudd of the Kirchner Landscape Products Division, It’s exciting to be involved in a project that demonstrates what can be accomplished when everyone commits to using low-impact, environment-friendly methods of design and construction.

Permeable interlocking concrete pavements (PICPs) are becoming more popular as communities face stormwater runoff regulations, he adds, as well as increased impervious cover restrictions, and adopt low-impact development (LID) or Leadership in Energy and Environmental Design (LEED) practices. In an attempt to manage stormwater runoff and relieve overtaxed drainage and sewer systems, many cities and states have incorporated Environmental Protection Agency regulations in their municipal design.

According to St. Louis Metropolitan Sewer District Director of Engineering Brian Hoelscher, Porous pavement, properly designed and installed, is a double winner. From an environmental protection perspective, it reduces the amount of surface runoff that is generated, as compared to traditional paved surfaces. From a ratepayer point of view, porous pavement will not be counted in calculating an individual property’s stormwater charge, thus saving the customer dollars every month.

While stormwater runoff management regulations vary among municipalities nationwide, water quality and/or quantity may be stipulated, including criteria for the reduction of such water pollutants as nitrogen, phosphorous, nitrates, metals, and sediment. From an engineering viewpoint, permeable pavements are infiltration trenches with paving on top that supports pedestrian and vehicular traffic. The system has allowed us to minimize stormwater runoff issues and meet design and structural requirements for the school, explains Bill Berthold, P.E., president of St. Louis-based Frontenac Engineering Group.

Moreover, Kirchner officials note, Eco-Stone offers the benefits of concrete as well as the distinct advantages of a permeable pavement system. Pavers are produced at Kirchner’s local facility in accordance with ASTM requirements for strength and quality. Compared to paving alternatives like asphalt, permeable concrete units help reduce the heat island effect by reflecting sunlight and releasing heat more rapidly (note Tech Talk, page 48). A wide range of colors also provides considerable freedom in design. Affirms designer Steve Dehekker, vice president of Hastings & Chivetta Architects in St. Louis, The pavers contribute to the sustainable aspect of the installation and enhance its architectural appeal. We alternated custom color units to define parking spaces for an overall effect resembling an outdoor plaza, rather than a parking lot.

As College School renovation general contractor, Kozeny-Wagner Construction, Arnold, Mo., aimed to satisfy specific project requirements while promoting interests of the wider community. Vice President Michael Kozeny asserts, More than just managing a project, we believe Kozeny-Wagner is responsible for understanding and supporting the needs of our clients, our community, and the environment. Our involvement on the College School campus and association with a sustainable design project have expanded our knowledge of the Eco-Stone product line. When applicable, we will recommend the pavers as an alternative solution to prevent additional storm water runoff.

Confirming an increase in the use of permeable pavers over the last few years, Kirchner Sales and Marketing Director Mark Wilhelms reports, In addition to the 17,000 square feet being installed at the College School, our permeable pavers have been used at the landscape architecture office of SWT Design and for parking on the Great Rivers Greenway trail segments at Grant’s Trail and Barathaven.

Additionally, permeable concrete pavement systems are finding more widespread acceptance in residential applications. Once wary of Îcostly and unprovenÌ green building practices, home builders and developers now are responding to impervious cover restrictions and increasing energy costs by adopting environmentally sound construction technologies, including Eco-Stone. The National Association of Home Builders has further fueled the trend by encouraging the use of ÎgreenÌ products in single and multifamily developments.

To meet growing demand for permeable concrete pavers, Kirchner has introduced Aqua-Bric. This pedestrian-friendly paver will allow greater variety in installation patterns to give architects and owners even more design flexibility. As pervious interlocking pavers, Aqua-Bric and Eco-Stone offer the structural support, durability, and beauty of traditional concrete pavers with the environmental benefit of permeability, Wilhelms affirms.