Green Roof for Tulsa City-County Central Library!

The Tulsa City-County Central Library, constructed in 1965, formerly included two reflecting pools flanking the main library entrance.  The reflecting pools were built over an underground parking structure - and over time -the pools began to leak, damaging cars and creating a hazard.  And so, the pools were emptied and sat abandoned for years.  They became an eyesore, and a maintenance issue. 

The library evaluate using the former pools as landscaping, but faced challenges due to soil loads on the parking structure roof.  But, observing rooftop gardens, they began to see other opportunities for reuse. 

After consultation with structural engineers, the library confirmed that a roof system would be feasible.  The project was fully funded by the American Recovery and Reinvestment Act "Green Project Reserve" adminstered by the Oklahoma Water Resources Board. 

The first step was to remove the old terrazzo and install a new waterproof membrane to correct leakage problems.  The next step was to add insulation and a root-stop barrier.  The bottom white later is styrofoam insulation, which was also helped to raise the bed.

Next, a moisture retention layer was added.  This was critical due to the long, hot, dry summer in Tulsa as well as the garden's location on a southern exposure.  Roof top gardens often also have moisture loss from constant winds.  Rather than using soil, LiteTop(r) growing media was utilized to help minimize weight. 

Plants were chosen to minimize the need for irrigation and maintenance.  A drip irrigation system was installed to assure plant survival while minimizing water consumption.  The landscaping design was developed specifically to deter misuse or vandalism of the beds.  The final installation is an attractive as well as educational addition to the library.  Along with overall beautification, the library has seen a decrease in the amount of abuse and litter in the surrounding plaza. 

Last year the Tulsa City-County Library System received two grants to install green stormwater management systems.  We have recieved a presentation from the Library showing the sites, design elements, and final products for both installations and will be posting them here.  Go by and check these out yourself!

The first is at the Judy Z. Kishner Library, located in a Sperry, OK. The library was completed in 2008 and lies in a two acre lot adjacent to the Osage Trail. Nearly the entire town, along with areas to the north, is prone to flooding. The contours and elevations of the library property did not allow positive drainage off the site and were a mosquito haven.

Since draining the water was not an option for this property, the idea of a rain garden took shape.To fund this project, the Library applied for a grant from the Amercina Recovery and Reinvestment ‘Project Green Reserve’ administred by the Oklahoma Water Resources Board. Due to the innovative nature of this problem resolution, the project was fully funded with the Green Reserve Grant Funds.

During construction, the existing surface depression was excavated further and the soil amended.  New vegetation, selected to enjoy the wet conditions, was planted. The finished result is an amenity for the library and the nearby trail as well as a stormwater management feature.