Sometimes everything doesn’t fit into the space allotted. This was the case with revitalizing Lower Cascades Park in the famous Indiana University basketball City of Bloomington (pop. 72,000). New life to a small, historic park included installing massive playground equipment and more parking. Asphalt was not a slam dunk for parking since there wasn’t room for more paving and a detention pond. The solution immediately rebounded back as 40,000 sf (4,000 m2) of permeable interlocking concrete pavement. Indianapolis-based Landscape Architect Debra Schmucker, President of Cornerstone Planning & Design and commissioned by the City to draw up plans for the revitalized park found the sixth man in permeable interlocking concrete pavement.
Completed in September 2005, the project represents the first permeable pavement project built by the City for the Department of Parks and Recreation. Appropriately named for the lovely waterfalls that run through it, Cascades Park was Bloomington’s first established in 1924. The Park was created to block the expansion of a nearby limestone quarry that would have tarnished this gem. In the Depression years, WPA and CCC took abundant limestone from the quarry for make work projects including walls that line Cascades Creek that bisects the park, shelters for drinking fountains and picnickers (see Figure 1) and a bathhouse for a swimming pool that once existed there.
According to Dave Williams, the City’s Director of Operations and Development in the Parks and Recreation Department, Bloomington is a very ‘green’ community. Two issues enabled the City to consider permeable pavement. First, the City had recently spent $5 million for a stormwater detention and park project upstream from Cascades Park to help improve the water quality of Cascades Creek running through it.
Mr. Williams noted that the project utilized “five pre-treatment stormwater cleansing structures, detention ponds, two wetlands, thousands of wetland plants all in an effort to clean the stormwater before it headed into Cascades Creek. Taking the easy route and building asphalt lots and watching the oil, gasoline and other contaminants flow into the creek didn’t make sense if we were going to continue our efforts to improve the stormwater quality and park ecology.”
The second issue concerned limited space to construct two small detention ponds likely required to handle stormwater flows from asphalt lots in the park. “Removing already limited green space in the park to use for detention didn’t make sense. Detention ponds (not required to be fenced in Indiana) were also a liability, plus aesthetic and maintenance concern,” Mr. Williams noted. In addition, permeable pavement would promote the longevity of towering trees in the park.
Ms. Schmucker researched permeable pavements for the City. Research pointed towards permeable interlocking concrete pavement with high infiltration capacities. “Elimination of detention facilities, an acceptable appearance for this park environment (a major concern for the City); all of these design criteria helped satisfy the ongoing goal to think progressively and set a good example for the public,” according to Mr. Williams. Costs were found to acceptable since the pavement combined paving and drainage costs into one facility.
Moreover, permeable interlocking concrete pavement gained the approval of the City’s utilities department without providing detention. Other permeable pavement types were considered including porous asphalt but lack of applications in the immediate area and concerns with freeze thaw cycles eliminated this option. Porous concrete was proposed by a local supplier after the project bid with pavers. The City stayed with permeable interlocking concrete pavement because it would provide a cost-effective, visually attractive solution.