Stormwater

The massive, unprecedented flood which hit UofL on August 4, 2009, causing $20.9 million in damages, was a wake-up call for many. It hinted at the increasing intensity of storms to come as our greenhouse gas emissions continue to warm the planet and alter the climate we once knew. But it also helped motivate us to take action to both mitigate our climate impact, and to adapt to a changing climate by getting serious about sustainable stormwater management.

UofL is working with Louisville's Metropolitan Sewer District (MSD) on a variety of projects to help keep runoff out of the sewer system. As VP for Business Affairs, LarryOwsley puts it, "When you have that much rain in that short a time, the sewers — which are large sewers — just back up and there's no place for the water to go." Even if the sewers can handle stormwater from UofL, the treatment plants at the end of the pipe often can't, leading to dangerous releases of untreated sewage into the Ohio River.

UofL is now pursuing means of lessening the risk of flood and reducing our campus' contribution to the problem by diverting stormwater from the sewer system all together through infiltration and rainwater harvesting projects, or by slowing its release through water absorbing changes to our campus landscape. Around campus, we are beginning to disconnect downspouts, install vegetated green roofs, and build rain gardens and bioswales to facilitate groundwater recharge through infiltration.

Stormwater Management Projects

UofL is making several changes to campus landscaping, parking lots and rooftops, with the help of $1.5 million in cost-sharing from MSD. We think that this significant investment today could essentially pay for itself by helping prevent millions of dollars in future flood damage. We are also hoping the projects at UofL will serve as an example for similar projects across the city on both public and private property. MSD's investment in Belknap campus stormwater projects is part of a 2005 $850 million agreement that MSD made in federal court with the U.S. Environmental Protection Agency and state regulators to reduce the incidence of combined sewer overflows into waterways during storm events.

Projects at UofL include:

• Rain Barrels: Rainwater harvesting from the roof of the Cultural Center for use in the campus Garden Commons.
• Bioswales: Vegetated bioswales are stormwater runoff conveyance systems which provide a natural alternative to sewers. They help reduce threats to water quality by infiltrating the first flush of storm water runoff and filtering the large storm flows they convey. UofL will utilize existing natural drainage swales whenever possible, and enhance them with native plants to encourage infiltration and filter out contaminants. A bioswale is designed to handle stormwater from the roof of the new College of Business expansion.
  
• Rain Gardens: Areas of campus will be redesigned to channel runoff into shallow depressions which will be replanted with deep-rooted, native species to facilitate infiltration, converting a waste problem (runoff) into a beneficial good (groundwater). Rain gardens are planned for the Law School courtyard and for the west side of Ekstrom Library.
  

• Pervious Pavements: UofL is moving away from the traditional method of creating hardscapes which prevent infiltration and channel stormwater to sewers. Instead, we are creating lots, roadways, plazas, and sidewalks by either pouring pervious pavement, as is being used in the Dental School renovation, or laying permeable pavers, as have been used in the Red Barn plaza and Grawemeyer Oval loop renovations, and the Garden Commons community gathering space.
• Green Roofs: Vegetated roofs are not only beautiful, but they help moderate temperatures to reduce the urban heat island effect and building energy demands for cooling and heating, while reducing storm water runoff, generating oxygen, and providing wildlife habitat in the urban landscape. They can also be designed as green spaces for urban dwellers looking to escape the concrete jungle. UofL has begun installing green roofs to help demonstrate their many benefits, with projects at the new College of Business Equine Addition (942 square feet), the Early Learning Center at Family Scholar House, and the new Cardinal Towne affiliated student housing and retail facility.
• Infiltration Basins: Traditional-looking parking lots, plazas and lawns can conceal advanced stormwater infiltration systems. Instead of draining to the combined sewer system, these areas drain to large underground infiltration basins capable of handling huge rainfall events and the water from surrounding rooftops. These designs were included in:
  
  1. The Ville Grill and Red Barn plaza 2011 renovations.
  2. The Grawemeyer Oval lawn renovated in 2011.
     
  3. The College of Business parking lot renovated in 2011.
  4. The lot behind Bettie Johnson Hall, the Urban Studies Institute, and University Planning, Design & Construction renovated in 2011.
  5. The Speed Museum expansion project has been designed with a large infiltration basin beneath the plaza which will be able to handle roof drainage from Strickler Hall, Life Sciences, and the College of Business.
  Researchers from UofL's Center for Infrastructure Research have installed monitoring equipment to study infiltration rates, storage capacity, and the performance of these designs.
  

Look for these Green Infrastructure Installations at UofL planned for 2012:

• Law School Courtyard Rain Garden
  
• Underneath the Eastern Parkway Overpass
• Speed School of Engineering Rain Garden
  
• Clinical & Translational Research Building (HSC)
  
• Ekstrom Library
• Green Roof and Rain Garden at the College of Business Expansion:
  

  Business School Equine Addition - Rain Garden Plan:
  - Impervious surface drainage areas (less green roof) = (3708 -942) = 2766 square feet
  - Required retention volume for ¾” runoff = ¾” x 2766 sf = 173 cubic feet
  - Provided retention volume = 1509 cubic feet (Total) 8’ x 8’ x 6.5’ x 0.30 = 125 cubic feet (infiltration trench) plus 1384 cubic feet surface storage (per grading plan surface model)
  Business School Equine Addition - Green Roof Plan:
  - The green roof total area will be 942 square feet (the gravel border is not included in this total).  The green roof material is a pre-vegetated sedum mat with 4”-6” fill material.