LAND AS THE RESOURCE - Low Impact Development and Sustainable Stormwater Management - page 75

Figure 3-20 The Victorian-era Phipps conservatory has designed a living building to serve
as the Center for Sustainable Landscapes.
environmental experts from both the private market and local academic institu-
tions worked to formulate a concept plan and detailed design. This effort led to
a building program that was both unique and innovative for both the city and
the region, and provided an important test of the living building concepts in
an existing urban environment. One critical issue was the fact that the existing
sewer system servicing the site was part of a century-old combined sewer, with
major water quality impacts downstream on the Monongahela River from CSO
discharges during wet weather. The city is served by a regional sewer system and
plant downriver on the Ohio, but the original sewers were build in streambeds
with stormwater inlets draining the surface and experience severe overflow and
discharge conditions. The new living building would be served by a wetland
treatment system, with an infiltration bed to avoid effluent discharge.
The concept plan included the capture of rooftop rainfall from the new glass
greenhouses (Figure 3-21) to meet the major consumptive use of potable water in
the complex for the irrigation of plants as well as the operation of display foun-
tains. All new parking areas would be built with porous AC pavement underlain
by stone beds for infiltration, with no runoff from the new site. The net result
would be a significant reduction in the flows into the existing combined system,
especially during wet weather.
This concept design, however, was not approved by city or state regulators.
The urban soil in the building location included residual materials and was of
poor quality for effluent renovation. Since the discharge of any effluent, no matter
how small, was not acceptable under the living building criteria, the two regu-
lations were in conflict. In addition, the proposed wetland treatment system of
400 gallons per day (gal/day) could not provide capacity for the much larger
wastewater flow (3,500 gal/day) from the full complex, so the existing discharge