THE FINANCIAL BENEFITS OF WATER CONSERVATION: THE TUCSON STORY MARY - PowerPoint PPT Presentation

THE FINANCIAL BENEFITS OF WATER CONSERVATION: THE TUCSON STORY MARY ALLEN, P.E. PETER MAYER, P.E. CANDICE RUPPRECHT BUSINESS PROCESS IMPROVEMENT WATER CONSERVATION PRINCIPAL MANAGER PIMA COUNTY REGIONAL WASTEWATER WaterDM RECLAMATION TUCSON WATER

AWE AVOIDED COST STUDY • Alliance for Water Efficiency grant funds from Walton Family Foundation focused on Colorado River Basin Initiative • WaterDM and City of Westminster Study • Tucson, AZ and Gilbert, AZ selected to participate • Goal of the study is to examine the impact of increased water use efficiency on customer rates

WATER USE IN THE US, 1900 - 2010 Includes fresh and saline water. Source USGS and Pacific Institute 2015

M&I WATER USE IN THE US, 1900 - 2010 Source USGS and Pacific Institute 2015

TUCSON WATER ANNUAL PRODUCTION (1940-2016) Water Production for TW Service Area (Acre-Feet) 140,000 120,000 Total Potable Water Use at 1985 Level Reclaimed 100,000 Water 80,000 60,000 CAP 40,000 20,000 TARP 0 2016 2016 1940 1950 1960 1970 1980 1990 2000 2010 Year Potable Production CAP Production TARP Production Reclaimed Production

RESIDENTIAL INDOOR GPCD 80.0 70.0 Indoor Average Gallons Per Capita Per Day (gpcd) 69.3 60.0 58.6 1999 vs. 2016 = 50.0 15.4% reduction 40.0 36.7 30.0 2016 vs . HE = 37.4% reduction 20.0 10.0 0.0 REU1999 REU2015 High-Efficiency (Aquacraft 2011d) Source: Water Research Foundation (2016) Residential End Uses of Water Update – #4309. Denver, CO.

INDOOR GPCD COMPARISON Statistically significant 20 reductions in: 18 • Clothes washer 16 Gallons per capita per day (gpcd) • Toilet 14 12 • Dishwasher 10 8 6 4 2 0 Clothes Toilet Shower Faucet Leak Other Bath Dishwasher washer REU1999 18.5 15.0 11.6 10.9 9.5 1.6 1.2 1.0 REU2015 14.2 9.6 11.1 11.1 7.9 2.5 1.5 0.7 Source: Water Research Foundation (2015) Residential End Uses of Water Update – #4309. Denver, CO.

WATER EFFICIENCY IS NOT ONE, BUT MANY APPROACHES • Utility-sponsored conservation & education programs • Rebates, Youth & Professional Education • Community outreach campaigns: Pete the Beak; Water Reliability • Increasing block rate structures • 4-Tier structure: $1.55,1-7 ccf; $3.00, 8-15 ccf; $7.48, 16-30 ccf; $11.75 > 30 ccf • Local ordinances: Xeriscape Landscaping (1991), Water Waste (1984) & Comm. Rainwater Harvesting (2008) • International Plumbing Code  Tucson Plumbing Code • National Policy that drives Innovation & technology improvements • Energy Star (2002) & WaterSense (2006)

SINGLE FAMILY AVG. ANNUAL USE 1985 - 2015 180 160 SF Household Avg. Annual Use (CCF) 1960s & 1970s 140 Typical landscape 120 100 Preferences shift… A typical landscape today 80 Present-day Typical landscape 60 40 20 0 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

TOTAL SYSTEM GPCD 1980 - 2015 200 180 160 140 System GPCD 120 100 80 60 40 20 0

POPULATION AND PER CAPITA WATER AND WASTEWATER USE 200 800,000 717,875 180 188 700,000 160 600,000 Gallons per Capita Per Day 140 512,000 500,000 130 120 Population 100 400,000 105 80 300,000 78 60 200,000 40 100,000 20 - - 1989 2015 System Per Capita Water Use (gallons/day) System Per Capita Wastewater Use (gallons/day) Service Area Population

HYPOTHETICAL, NON-CONSERVING WATER DEMAND 160.0 Daily Water Production & 140.0 134.4 Wastewater Flows: 120.0 -1989 actual Avg. Daily Production/Flow (MGD) - 2015 actual 96.4 100.0 93.3 - 2015 hypothetical 80.0 80.0 1989: 188 / 107 gpcd 56.2 60.0 54.0 Pop. 512,000 2015: 130 / 79 gpcd 40.0 Pop. 717,875 20.0 0.0 1989 2015 2015 Hypothetical Water Wastewater

• Due to conservation, per capita water use in Tucson has dropped 45% and wastewater by 35% since 1989. • Yet…. costs to customers continue to increase. • Some customers are confused and frustrated. • What is the impact on water and wastewater rates due to conservation? “WHY ARE MY RATES GOING UP AGAIN WHEN I KEEP CONSERVING WATER?!”

WATER SYSTEM AVOIDED COSTS • Water Treatment Infrastructure • Pumping & transmission expansion • Water Resources • Operating Costs How Much Additional Cost to Tucson Water meet non- conserving, hypothetical demand of 134 mgd?

WASTEWATER SYSTEM AVOIDED COSTS • 2015 Avg. Daily Flow ~ 56.2 MGD • Hypothetical Non-Conserving Avg. Daily Flow ~ 80 MGD • Current System Max. Treatment Ability ~ 95 MGD • In this analysis, wastewater treatment capacity water increased to 107 MGD to meet Hypothetical Non-Conserving Daily Flow range What additional wastewater system infrastructure and costs to meet 80 mgd avg. daily flow?

ADDITIONAL COSTS OF MEETING A NON- CONSERVING DEMAND… THAT HAVE BEEN AVOIDED • Additional $22 million per year for water system O&M • $140,000,000 for new Avra Valley Transmission Main CIP • $15 million for new 7 MGD recycled water facility • Additional $6.4 million per year for wastewater treatment O&M • $195,000,000 for additional 12 MGD of wastewater capacity, financed over time

CUSTOMER RATE IMPACT • Current avg. single-family, water customer uses 98.9 ccf/year , and pays for 84 ccf/year of wastewater treatment. • At current water rates, the avg. single-family customer pays $847 per year for water and sewer. • Under the non-conserving scenario (assuming 188 gpcd) the average single-family customer would pay $976 per year for water and sewer. Due to water efficiency, rates today are nearly 15.3% LOWER than otherwise necessary.

Impact to an Average Single-Family Customer - Tucson, AZ 120 $1,200 100 $1,000 Annual Water and Wastewater Use (kgal) $976 Annual Water & Wastewater Bill - $ $847 82.8 80 $800 63.0 60 $600 97.2 40 $400 74.0 20 $200 0 $- 2015 Actual Non-Conserving Hypothetical Water Use (kgal) Wastewater Discharge (kgal) Annual Water & Wastewater Bill - $

BREAKDOWN OF AVOIDED COSTS Tucson Water rates are Wastewater Treatment, 21.8% Wastewater Treatment Operation, 10.8% 22.3% lower today and Pima County WR rates are 7.8% lower today than otherwise necessary if Water Transmission, per capita water demand 11.8% had not been reduced. Reclaimed Water, 0.0% Water Treatment Operation, 38.6% Interest and Debt Service, 17.0%

STRENGTH OF SEWER FLOWS 500 23500 22781 23000 450 429 22500 400 22000 338 350 21500 Flow in Million Gallons/year 300 Average Strength (mg/L)/year 21000 250 216 20500 200 20000 20424 205 150 19500 100 19000 50 18500 0 18000 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 TSS BOD Combined Influent Flows for Agua Nueva and Tres Rios

IMPACT TO THE SEWER PIPES • Scour velocities may take longer to attain in newer developments with lower flows • Flushing of pipes may be required • Potential for more odors in pipes • Potential for corrosion in pipes • Terminal ends may require steeper slopes • Cost goes up for deeper sewers

FLUSHING THE PIPES

PIPE MAY REQUIRE STEEPER SLOPES Table 5.1 Minimum Slopes for Gravity Sewer Lines Pipe Diameter Minimum Slope *Full-Flow (inches) (ft/ft) Velocity (ft/sec) 6 (terminal reach) 0.0110 3.0 8 (terminal reach) 0.0100 3.5 8 (non-terminal reach) 0.0044 2.3 10 0.0025 2.0 12 0.0019 2.0 15 0.0014 2.0 18 0.0011 2.0 24 0.0008 2.0 *Manning’s (n) value of 0.013 used

ODORS AND CORROSION

• Water and wastewater rates have increased because of the increasing costs of providing 24/365 service, while maintaining and improving infrastructure to meet regulatory treatment requirements. • Decreasing demands are a balancing act: Revenue v. Resources • The typical Tucson single-family customer pays 15% less today, than they would need to be if water efficiency had not been achieved. Bottom Line: When Everyone Conserves, Everyone Saves

QUESTIONS & DISCUSSION THANK YOU! MARY.ALLEN@PIMA.GOV CANDICE.RUPPRECHT@TUCSONAZ.GOV