Rice University
OP-23: Rainwater Management

The Harris Gully Natural Area is the key component of Rice's stormwater management system. It acts as a rain garden on Rice’s campus, reducing the rapid flow of stormwater and increasing its infiltration into the soil. The Gully is comprised of plantings of native grasses, wildflowers, trees, and shrubs, thereby creating a replica of the natural system once widespread in the Houston area. Rice University also has seven green roofs, which are important upstream LID features distributed across campus. Locations include the OEDK, South Plant, Baker Servery, Duncan College, McMurtry College, West Servery, and the Biosciences Research Collaborative. At the Rice Children’s Campus, a rainwater collection system captures rooftop and courtyard run-off and utilizes an 8,000-gallon underground storage tank. Yearly rainfall harvest is estimated at 233,642 gallons. This is of course non-potable water. The estimate was developed by our landscape architecture consultant as part of the submittal to the USGBC for the LEED-Silver certification for the Rice Children’s Campus. Out of the 19 miles of sidewalks and paths on Rice's campus, there are 0.8 miles of pervious concrete sidewalks, and 4 miles of granite sidewalks and paths. Thus, about 1/4 of Rice's campus employs porous paving. Rice's North Annex Parking Lot has three planting beds in between the parking spaces which serve as bioswales. Furthermore, the path leading to the Harris Gully Natural Area serves as a bioswale, channeling water and directing it to the Gully's detention storage.

Rice University has adopted a policy for stormwater management from the City of Houston and Harris County Flood Control District which essentially mandates Low Impact Development practices. These entities have significant regulations regarding detention and compensatory storage due to the frequency and severity of flooding in Houston. For compensatory storage, regulations require that there be no net loss of volume in the 100-year flood plain. Thus, because a portion of Rice’s campus lies in this flood plain, if the University fills a cubic foot of dirt from the land, then it must excavate a cubic foot of storage volume elsewhere in that flood plain (and this volume must be open to the sky). For stormwater detention, regulations require that for every acre of impervious land cover, 0.55 acre-feet of storage must be provided. See page 6-21 ofhttp://www.hcfcd.org/downloads/manuals/HCFCD_PCPM_Dec2010.pdf Currently, the Harris Gully Natural Area on Rice’s campus meets both the compensatory and detention storage requirements for most of the campus; however, as Rice continues to develop, the University has started to use other methods to meet the storage and detention requirements mandated by the City of Houston. For example, the lawn in front of Rice's recently constructed continuing studies building, the Anderson-Clarke Center, has a slight depression so as to provide its own compensatory storage on-site. Furthermore, Rice actively seeks out areas where sidewalks and other impervious materials can be removed.