Four Years Later: Successes and Challenges for the Water Conservation Program at Stanford University
Margaret (Marty) Laporte
Stanford University, Utilities Division, 327 Bonair Siding, Stanford, California 94305. USA
Michelle L. Maddaus
Maddaus Water Management, Alamo, California 94507 USA
William O. Maddaus
Maddaus Water Management, Alamo, California 94507 USA
ABSTRACT
This paper describes successes, challenges and practical aspects of implementing water conservation measures at a large university campus that is similar in many respects to city of 25,000 people. The water conservation program at Stanford University has reduced water usage by about 10 percent over the last four years despite adding new buildings during the same period. Stanford is on schedule to meet its goal of expanding the campus but holding water use down to a strict level, required by Santa Clara County.
Stanford University is located on the San Francisco Bay Peninsula, approximately 30 miles south of San Francisco California. In 2000, the university received a General Use Permit (GUP) from Santa Clara County for development of additional 2,035,000 net square feet of academic and academic support facilities (a 20 percent expansion). The approval of the 2000 GUP and the EIR resulted in specific requirements, one of which was the completion of a Water Conservation, Reuse, and Recycling Master Plan (Master Plan). The Plan’s key requirement is for Stanford not to exceed its domestic water allocation from the San Francisco Public Utilities Commission (SFPUC). SFPUC typically supplies 100% of the domestic water for Stanford University, with a daily average allocation of 3.033 million gallons per day (mgd).
Stanford staff worked with Maddaus Water Management (MWM) to develop a 10-year Master Plan. Using MWM’s Water Conservation Cost-Effectiveness evaluation software (DSS model), Maddaus:
Reviewed existing water consumption in key campus water use groups;
Evaluated and recommended 14 water conservation measures that could be implemented; and
Estimated water savings for each measure.
The 14 domestic water conservation measures included:
Replacing toilets and showerheads in student housing and academic and athletic facilities;
Water audits of residential areas;
Requiring the use of low water use plantings;
Improving irrigation efficiency and moving some irrigated landscape off the SFPUC domestic supply and on to a well and lake supply.
The Master Plan and water conservation measures were submitted to Santa Clara County in December 2001. Implementation of the recommended water conservation measures began in earnest in 2001. To date Stanford has partially implemented 10 of the 14 measures plus additional measures with variable success. As of June 2005, the total cost for implementation of projects is $1.5 million, while the estimated savings for completed projects are 0.26 mgd. Since most of the buildings on campus are metered, the total metered domestic water consumption is tracked monthly, while annual consumption trends for key groups are reviewed in detail. This analysis has shown that conservation works to save water; 9.6 percent of baseline demand has been saved to-date. Stanford is on track with the Plan’s estimated savings by 2005 and more than halfway to the goal of saving 16% of baseline consumption by 2010. The cost of conservation savings to-date is less than the current price of purchasing water from the
SFPUC so the conservation has been cost-effective.
Although the results of the Master Plan and Stanford’s Water Conservation Program are site-specific, the methodology for reviewing water use and metering data, establishing baseline consumption, and developing water conservation measures is applicable to other educational institutions. Flexibility of the final program and on-going evaluation of effectiveness of measures are critical to obtain best water conservation results.
INTRODUCTION
The objective of this paper is to explain the methodology of creating a water conservation program and discuss the results of 4 years of current efforts. The following topics will be discussed:
1. History of Campus Development
2. Overview of Stanford’s Water System
3. Reviewing Historical Water Use and Metering Data
4. Development of Water Conservation Measures
5. Results of 2001-2005 Water Conservation Efforts
6. Conclusions and Recommendations
Water conservation, reuse and recycling should be based on the need for and benefit from saving water. The need to conserve water at Stanford, as in many communities throughout California and the world, is critical because of limited water supply and the desire for the sustainable use of water resources. The cost savings from water conservation, reuse and recycling primarily are derived from reduced domestic purchases, reduced wastewater discharge costs and from the deferred need to acquire new water supplies. Selection of water conservation, reuse and recycling measures that are applicable to Stanford was based on a review of projected water demands and growth on campus.
1. History of Stanford Campus Development and Need for the Master Plan
Stanford University is located on the San Francisco Bay Area Peninsula in northern California. Stanford lands are still largely undeveloped and span two counties – Santa Clara and San Mateo. The neighboring cities in Santa Clara and San Mateo counties comprise densely populated urban communities. The original campus included twelve classroom buildings, two dormitories – one for women and one for men, and engineering laboratories. Today, 120 years later, many dozens of classrooms, laboratories, libraries, dormitories, and other facilities occupy more than nine million square feet at Stanford. The University is still growing, renovating existing buildings, adding new academic and athletic facilities, and housing for students and faculty.
The central academic campus of Stanford University is located in unincorporated Santa Clara County. Santa Clara County requires permits for all Stanford development projects. After a lengthy and complicated process, in 2000, Stanford University received a multi-year General Use Permit (GUP) to build 2 million square feet of academic, housing, and other campus facilities, a 20 percent expansion. The 2000 GUP specifies various conditions of approval for new development at Stanford. One significant condition relates to water conservation and states that:
Within twelve months of General Use Permit approval, Stanford shall prepare and submit to the County Planning Office for review and approval a Water Conservation, Reuse and Recycling Master Plan, which will identify measures for reducing potable water use on campus. Measures included in the plan may be required as conditions of approval for proposed building projects and/or through the annual General Use Permit monitoring process. The overall goal of the plan shall be to ensure that Stanford does not exceed its allocation of 3.033 million gallons per day (mgd).
In 2001, Stanford hired Maddaus Water Management to review historical water use data and use the DSS model to prepare the Water Conservation, Reuse, and Recycling Master Plan. The information presented in this report was generated during the efforts to complete the required Master Plan.
2. Overview of Stanford’s Water System
When the campus first started in the late 1800s, there were no Bay Area-wide water distribution systems and local surface water and wells were nominally adequate for the rural and sparse population. For many decades, Stanford University used local surface and groundwater supplies as the only sources of domestic and agricultural water before the City of San Francisco developed the Bay Area-wide San Francisco Public Utilities (SFPUC) Hetch-Hetchy Water Distribution system. In the 1940s, Stanford University started purchasing domestic water form SFPUC. Later in the 1960s, when SFPUC built additional pipelines in the foothills, Stanford added two additional connections to the SFPUC system. Since then, the SFPUC- Hetch-Hetchy domestic water has been the main source of domestic water for academic, housing, and athletic use on campus. Wells and surface water continue to be used, but mainly for irrigation of Stanford lands.
The Stanford Facilities Operations Water Shop operates the domestic water system that provides potable water to the Stanford campus. The Stanford domestic water system meets all state and federal water quality requirements. The majority of the domestic system has been installed since the early 1960s, but parts of the system date from the early 1930s. Backup potable water supply is provided by five wells on Stanford property.
The Stanford Water Shop also operates a non-potable (lake) water system on the Stanford campus. The lake water supply is used for irrigation and backup fire protection. Since about 1985 there has been a program to maintain and expand the lake water system to irrigate areas with the non-potable water instead of the domestic water. The lake water system includes Searsville Lake and Felt Lake. The Stanford University Utilities Division meters campus domestic water consumption separately at most buildings and landscaped areas using more than 1400 meters. The monthly metered consumption data are stored in the Utilities Metering Database (UMD). The UMD is invaluable for tracking utility consumption trends and storing historical metering data and related information for billing.
3. Review of Stanford Historical Water Use and Metering Data
In order to accurately account for water conservation benefits from water conservation program savings, it is necessary to establish a baseline water use from historical data. The evaluation of historical water supply production for Stanford involved the analysis of available metering data between 1995 and 2000. Data show that the 12-month moving average from 1995 to 2000 for the domestic system increased slightly and was at approximately 2.7 mgd for fiscal year 1999-2000, the base year for the 2000 GUP (Figure 2). This paper focuses specifically on Stanford’s progress after aggressive water conservation implementation since 2001. Note the downward trend in water consumption since implementation was begun in 2001.
To measure trends in water consumption Stanford has been following the nine historical water use categories established in Master Plan (Table 1). The categories were chosen to analyze domestic water use and consumption based on monthly-metered data from the UMD.
Table 1. Nine categories and their average annual percent of total demand for 2000 (2.7 mgd) and 2005 (2.5 mgd).
The 2005 average domestic water demand based on metered data from the first two quarters in FY05 is illustrated in Figure 3. Note that student housing, Central Energy Facility (CEF), and the faculty/staff housing continue to be the three largest categories of use. This does not include unaccounted-for water. Unaccounted-for water is approximately 6.6 percent. Stanford’s domestic system is very efficient compared to the industry goal of less than 10 percent unaccounted-for water as determined reasonable by the American Water Works Association (AWWA, 1996).
The change in the distribution of water use by category is due to the additional new academic facilities, new student housing buildings, slower construction rate than originally projected, and to conservation measures in those categories that saw their percentage of the total consumption decline.
Figure 3. Average Annual Demand, by Category for Stanford’s Domestic Water System through February 2005.
To project the growth in future water demand, the Master Plan identified historic campus development and water use and incorporated campus expansion plans under the 2000 GUP. Potential increases in benefits from plumbing codes were compared to campus growth. July 1, 2000 through June 30, 2001 was the baseline year for water projection, assuming a steady development rate until 2010, with and without conservation (Figure 4). Without implementation of this Master Plan, the projection was from the average daily demand in 2000 of 2.7 mgd to as much as 3.6 mgd in 2010 at the anticipated end of the 2000 GUP program. Therefore, the goal of the conservation/recycling Master Plan is to reduce the demand by approximately 16 percent or 0.57 mgd to keep the demand below 3.033 mgd.
The actual rate of development has been slower and is now projected to be beyond 2010. If we assumed the 2000 GUP build out to extend through 2010, Figure 4 illustrates the projected consumption according to the Master Plan with and without conservation and the actual consumption through 2004.
Figure 4. Projected Baseline Water Use from the Master Plan With and Without Conservation Through 2010 and actual use through 2004.
3.1 Major End Uses of Domestic Water
In addition to the historical water use by category, Maddaus Water Management further reviewed Stanford’s UMD data to determine major end uses of water and additional opportunities for water savings. Some end uses of water are similar across nearly all categories. Two of these major end uses of domestic water are: (1) toilets; and (2) landscape irrigation (Table 2). Water use for toilet flushing is based on calibrating a fixture model to the various categories of water use. Estimates were made for the number of persons using the facilities in each category, and the number of times per day they used them.
Table 2. Percent Internal and External Domestic Water Use by Category
Category Internal Water Use (%) External Water Use (%)
For indoor water use the total amount of water used for flushing toilets is estimated to be 280,000 gallons per day, totaling about 10 percent of the total domestic water use on campus. The majority of the water use for toilets is in two housing categories: student and faculty/staff housing. Irrigation water use in these categories is typically not metered separately, so it was determined from review of the seasonal pattern of water billing data and assuming that nearly all of outdoor or seasonal use was for landscape irrigation. Irrigation is a significant use of domestic water, at about 22 percent of overall domestic use. Over 70 percent of the irrigation using domestic water occurs in the housing areas, particularly in faculty/staff housing. The two leading end uses of water: toilet flushing and landscape irrigation represent over 30 percent of the domestic water used on campus. Therefore, these two end uses are specifically targeted by conservation measures, in addition to evaluation of other end uses.
4. Development and Implementation of 14 Water Conservation Measures
The development of the water conservation measures for Stanford University took five main steps.
Step 1: It was important to understand current infrastructure on campus and evaluate all potential water conservation opportunities.
Step 2: Then using this information 14 new conservation measures were recommended.