Overall Rating Reporter - expired
Overall Score
Liaison Tavey Capps
Submission Date Feb. 25, 2015
Executive Letter Download

STARS v2.0

Duke University
OP-26: Water Use

Status Score Responsible Party
Complete Reporter Tavey Capps
Environmental Sustainability Director
Office of the Executive Vice President
"---" indicates that no data was submitted for this field

Level of water risk for the institution’s main campus:
Medium to High

Total water use (potable and non-potable combined)::
Performance Year Baseline Year
Total water use 439,713,745 Gallons 645,306,519 Gallons

Potable water use::
Performance Year Baseline Year
Potable water use 419,713,745 Gallons 645,306,519 Gallons

Figures needed to determine "Weighted Campus Users"::
Performance Year Baseline Year
Number of residential students 5,300 4,640
Number of residential employees 0 0
Number of in-patient hospital beds 957 957
Full-time equivalent enrollment 14,850 13,002
Full-time equivalent of employees 30,472 22,597
Full-time equivalent of distance education students 0 0

Gross floor area of building space::
Performance Year Baseline Year
Gross floor area 15,447,892 Square feet 13,471,306 Square feet

Area of vegetated grounds::
Performance Year Baseline Year
Vegetated grounds 568 Acres 568 Acres

Start and end dates of the performance year and baseline year (or three-year periods):
Start Date End Date
Performance Year July 1, 2013 June 30, 2014
Baseline Year July 1, 2005 June 30, 2006

A brief description of when and why the water use baseline was adopted:

In October of 2007, The North Carolina Drought Management Advisory Council (NCDMAC) listed Durham County, along with 54 other counties, in the highest category of D4- Exceptional Drought. As a result of the extremely dry conditions experienced by the entire state, Duke University convened Water Conservation Steering & Working Groups, which analyzed all potable water use on campus. In order, to measure progress since this point, Duke adopted fiscal year 2005-2006 as our baseline for this utility.

Water recycled/reused on campus, performance year:
20,000,000 Gallons

Recycled/reused water withdrawn from off-campus sources, performance year:

A brief description of any water recovery and reuse systems employed by the institution:

A new reclamation pond will collect rainwater and runoff from 22 percent of the main campus area for use in a nearby chilled water plant, which pumps water across campus to cool buildings. The pond is expected to save about 100 million gallons of potable water a year.

Condensation in University, Medical Center and Health System cooling systems is reclaimed for use in Duke's Chilled Water Plant's cooling towers. Cooling tower blowdown water is sent through an RO system and reused in cooling towers.

Water from the Asiatic Arboretum pond in Sarah P. Duke Gardens is used to water seasonal plants in the terrace beds of the Gardens. Additionally, in the Charlotte Brody Discovery Garden at Duke Gardens, rainwater is collected to water the surrounding landscape. Duke Gardens staff have also hosted workshops focused on rainwater harvesting at home.

The Fitzpatrick Center for Interdisciplinary Engineering, Medicine and Applied Sciences (FCIEMAS), which opened in 2004, has a 70,000-gallon cistern underground to collect rainwater that is used to irrigate the nearly two-acre complex.

Duke has multiple cisterns installed across campus that collectively hold approximately 260,000 gallons of stormwater. Water from cisterns is used primarily for irrigation.

All irrigation water used on Duke's golf course is non-potable stormwater, which is collected from ponds on site.

A brief description of any water metering and management systems employed by the institution:

Water meters currently track the water consumption from ~ 90% of campus.

A brief description of any building retrofit practices employed by the institution, e.g. to install high efficiency plumbing fixtures and fittings:

see below

A brief description of any policies or programs employed by the institution to replace appliances, equipment and systems with water-efficient alternatives:

see below

A brief description of any water-efficient landscape design practices employed by the institution (e.g. xeriscaping):

Landscaping at Duke University is designed in a way to create a natural environment that is not dependent on water. Drought-tolerant plants and green roofs on campus with succulents are significant examples of these efforts. Ornamental stones are used to hold water, manage runoff, avoid rutting, and prevent weeds. These projects are self-sufficient once they are established, making them an economically efficient investment in sustainable practices.

In the Duke Gardens, water conservation is a high priority and xeriscaping plays a large role in plant decisions. Plants are preferred that require little irrigation once established, and plants that need more water are sited appropriately for efficient water use. Proper mulching is also a standard procedure for all planting areas.

A brief description of any weather-informed irrigation technologies employed by the institution:

Rain sensors are an ordinance in the city of Durham. After a quarter inch of rain, programmed irrigation systems at Duke University shut down. The Duke Gardens and the new Duke Comprehensive Cancer Center site have Smart Controllers for their irrigation systems. The irrigation system for the Doris Duke Center is currently controlled by a ‘smart’ control valve. This system has sensors that respond to recent rainfall and adjusts the duration of irrigation accordingly based on soil moisture.
Where feasible, Duke University Grounds and Sarah P. Duke Gardens use drip irrigation to further conserve water used for landscape irrigation.

A brief description of other water conservation and efficiency strategies employed by the institution:

Recent Initiatives

Conservation measures identified by a water audit of 6 buildings in 2012 are expected to produce an 8 million gallon reduction in water consumption each year at Duke. A new reclamation pond will collect rainwater and runoff from 22 percent of the main campus area for use in a nearby chilled water plant, which pumps water across campus to cool buildings. The pond is expected to save about 100 million gallons of potable water a year. Duke is also helping to improve the watershed it relies on through a stream restoration project on campus.

Sustained Conservation

Through dedicated efforts on campus, Duke reduced its water use by 50 percent month over month from the previous year during the drought. In the years following the drought, there has been an estimated sustained reduction in water consumption of 35 percent. While many of the measures below were first initiated during the drought, they continue to contribute to sustained water conservation on campus.

Conservation Measures – Buildings
- Installed over 3,000 low-flow aerators on lavatories
- Installed over 3,000 low-flow flush valves on urinals and toilets
- Installed over 500 low-flow shower heads
- Corrected single pass cooling on lab equipment
- Installed hand sanitizers in residential hall bathrooms, kitchens, laundry room and common areas
- Installed 200 new high efficiency front load washing machines
- Modified sterilizers at all Duke University Medical Center facilities
- Performed a water audit on campus buildings
- LEED green building commitment

Conservation Measures – Central Plants

- Piped the reclaimed reverse osmosis water (RO) and air handler unit (AHU) condensate from campus buildings to use for make-up water in the Chilled Water Plant cooling towers
- Installed a RO system on the cooling tower blowdown to clean this water and reuse in the cooling towers
- Drilled two wells to provide tower make up water
- Pumping water out of the creek for cooling tower make up
- Installed a condensate transfer system to move condensate between East and West Steam Plants
- Alternate sources of water accounted for over 40 million gallons of water (33%) in FY10 at Chilled Water Plant 2

Reclaimed Water Conservation Measures – Irrigation

- Installed drought-tolerant landscaping on campus
- Designed temporary system to irrigate essential athletic fields that involves the use of reclaimed water. Tanks installed under the bleachers at Soccer/Lacrosse Stadium
- Installed cisterns to collect water for watering of Williams Field
- Increased the size of irrigation ponds on golf course to allow for more natural water storage

Conservation Measures – Educational and Community

- Supplied the University and Medical Center staff, employees and students with 10,000 free low flow shower heads for their homes (total savings of ~73 million gallons of water)
- Raise water conservation awareness by strategically placing signs at decision-making points like faucets, showers, water fountains and toilets
- Several of the monthly Green Devil Challenges have focused on water conservation

The website URL where information about the institution’s water conservation and efficiency initiatives is available:
Data source(s) and notes about the submission:

GSF #'s exclude parking decks that do not have water infrastructure

GSF #'s exclude parking decks that do not have water infrastructure

The information presented here is self-reported. While AASHE staff review portions of all STARS reports and institutions are welcome to seek additional forms of review, the data in STARS reports are not verified by AASHE. If you believe any of this information is erroneous or inconsistent with credit criteria, please review the process for inquiring about the information reported by an institution or simply email your inquiry to stars@aashe.org.