1. Title Slide An investigation funded through the INNOVATIVE WATER STRATEGIES Division of the Texas Water Development Board 1

2. Research Team   Meredith Blount Miller – Meadows Center   Stacy Bray – Meadows Center   David Venhuizen, P.E. – Venhuizen Water Works   Karen Ford – White Hat Creative 2

3. “Building-scale” Systems Independent rainwater harvesting system for each building THE strategy for all buildings: not an option 3

4. Collective O&M and ASSURED backup supply system 4

5. Study Focus: Texas Hill Country Photo Courtesy of Hill Country Alliance- 2012 Calendar Contest 5

6. Water Supply Options Private well on each lot Community well and water system 6

7. Water Supply Options Connect to area-wide water system 7

8. Water Supply Options Regional pipelines 8

9. Water Supply Options Rainwater Harvesting!! 9

10. “Large- Scale” Rainwater Harvesting Systems 10

11. Why is a development- wide rainwater harvesting SYSTEM a good option? 11

12. Rainwater Harvesting is MORE EFFICIENT 12

13. 83% of rainfall onto the Barton Springs watershed was lost to evapotranspiration, and never made it to a reservoir or aquifer. 13

14. Rainwater Harvesting is MORE EFFICIENT 14

15. Rainwater Harvesting “FITS” IN THE HILL COUNTRY 15

16. Rainwater Harvesting REDUCES UP FRONT COST Developers should like this a lot! 16

17. Rainwater Harvesting REDUCES FISCAL RISK Developers should like this a lot! 17

18. Rainwater Harvesting is UNDER THE USERS’ CONTROL 18

19. Rainwater Harvesting is MORE RELIABLE 19

20. Rainwater Harvesting is MORE SUSTAINABLE 20

21. Roof-harvested rainwater is BETTER WATER 21

22. Water from wells and reservoirs is DEGRADED from quality of the original rainwater. 22

23. Rainwater Harvesting USES LESS ENERGY 23

24. Many reasons to consider building-scale RWH! 24

25. Overview of Project Activities YYYYield-demand modeling BBBBackup supply options RRRRegulation and governance BBBBuilding design issues CCCCost effective analysis MMMMarketability SSSSustainability OOOOutreach/dissemination 25

26. The Modeling Process  Simulate rainwater collection and use in house  Shows “right size” of RWH facilities  “Right size” = size required for long-term sustainability  Determined by backup supply requirements  ASSURED backup supply = RELIABILITY 26

27. Rainwater Harvesting Model  Average rainfall models inadequate  Weather is not average  Multi-year model  Through wet and dry cycles  Used 25-year model, 1987-2011  Covers the “critical period” 27

28. Courtesy of John W. Nielsen-Gammon Professor and Texas State Climatologist Department of Atmospheric Sciences 2828

29. Lowest 12-month rainfall totals 1987-2011 2929

30. Right-Size for Outlier  2010-2011 drought controls “right-sizing”  Outlier  Very infrequent  Right-sized for any future conditions  Reliable and sustainable 30

31. 3131

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34. Roofprint Roof area off of which rainwater is collected 34

35. Roofprint is the plan area of the ROOF, all the roof, NOT the HOUSE area 35

36. Interior Water Use 36

37. Interior Usage Rate for RWH  35 gpcd – presumed by RWH designers Is this reasonable? Is this reasonable?  100 gpcd – “Standard” rate for “conventional” water system planning This is NOT residential INTERIOR water use This is NOT residential INTERIOR water use gpcd = gallons per capita (person) per day 37

38. Water usage used for design of on- site wastewater systems  60 gpcd with “conserving” fixtures  Actual water use observed to be ~50 gpcd ~50 gpcd 38

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40. 40

41. Usage Rates in RWH Model  50 gpcd – “default” rate  45 gpcd and 40 gpcd – better demand control 41

42. Modeled Household Occupancies  2-person occupancy “Empty-nesters”/seniors “Empty-nesters”/seniors  4-person occupancy “Standard” 3-bedroom house, likely the bulk of “normal” subdivision market “Standard” 3-bedroom house, likely the bulk of “normal” subdivision market 42

43. Irrigation Water Use 43

44. Wastewater Reuse for Irrigation 44

45. 45

46. Modeling Results Summary 46

47. Example Modeling Results 47

48. Dripping Springs Interior Usage Only Roofprint 4,500 sq. ft. Cistern capacity35,000 gallons Occupancy 4 persons Water usage rate 50 gpcd Backup supply requirements 1996 2,000 gallons 2008 4,000 gallons 2009 14,000 gallons 2011 18,000 gallons Total = 38,000 gallons 48

49. Dripping Springs Interior Usage Only Roofprint 4,500 sq. ft. Cistern capacity35,000 gallons Occupancy 4 persons Water usage rate 45 gpcd Backup supply requirements 2009 4,000 gallons 2011 10,000 gallons Total = 14,000 gallons 49

50. Dripping Springs Interior Usage Only Roofprint 4,500 sq. ft. Cistern capacity35,000 gallons Occupancy 4 persons Water usage rate 40 gpcd Backup supply requirements 2011 2,000 gallons Total = 2,000 gallons 50

51. Dripping Springs Interior + Irrigation Usage WITHOUT wastewater reuse Roofprint 4,500 sq. ft. Cistern capacity35,000 gallons Occupancy 4 persons Interior usage rate 50 gpcd Irrigated area 2,400 sq. ft. Irrigated area 2,400 sq. ft. Backup water supply required in 13 years Max. yr. = 58,000 gallons in 2011 2 nd most = 40,000 gallons in 1996 3 rd most = 38,000 gallons in 2008 Total over 25 years = 268,000 gallons 51

52. Dripping Springs Interior + Irrigation Usage WITHOUT wastewater reuse, larger system Roofprint 7,000 sq. ft. Cistern capacity50,000 gallons Occupancy 4 persons Interior usage rate 50 gpcd Irrigated area 2,400 sq. ft. Backup supply requirements 2009 6,000 gallons 2011 28,000 gallons Total = 34,000 gallons 52

53. Dripping Springs Interior + Irrigation Usage WITH wastewater reuse Roofprint 4,500 sq. ft. Cistern capacity35,000 gallons Occupancy 4 persons Interior usage rate 50 gpcd Irrigated area 2,400 sq. ft. Backup supply requirements 1996 2,000 gallons 2008 6,000 gallons 2009 14,000 gallons 2011 22,000 gallons Total = 44,000 gallons 53

54. Overview of Project Activities YYYYield-demand modeling BBBBackup supply options RRRRegulation and governance BBBBuilding design issues CCCCost effective analysis MMMMarketability SSSSustainability OOOOutreach/dissemination 54

55. Options for Backup Supply System A private well for each building Community well, “minimal” distribution system Community well + tanker truck delivery Connection to existing PWS system Tanker truck delivery from potable water supply 55

56. Tanker Trucks Supplied by Public Water System  Likely to be predominant method  Favored by developers – no up front costs  Regulatory issues – requirement for ASSURED supply?  How formalized?  What will it cost to set up? 56

57. Tanker Trucks Supplied by Public Water System  Conditions of service for guaranteed supply  Cost of guarantee?  Commercial hauler, or utility/HOA truck  Supply capacity, number of trucks available  Regulatory status  Backup requirement must be very limited 57

58. Tanker trucks supplied by a public water system REQUIRE that you hold backup supply to low levels. 58

59. Tanker Truck System: Capacity Limitations Development with 100 houses 1 House = 1 Truck / Month = 100 Trips / Month 59

60. Tanker Truck System: Capacity Limitations 22 working days in a month 100/22 = 4.5 truck trips per day One tanker truck, full time for one development! 22 working days in a month 100/22 = 4.5 truck trips per day One tanker truck, full time for one development! 60

61. Is the private sector ready for this kind of demand?  Ability to meet intermittent demand  Ability to expand fleet as number of developments grows  Further investigation needed 61

62. Overview of Project Activities YYYYield-demand modeling BBBBackup supply options RRRRegulation and governance BBBBuilding design issues CCCCost effective analysis MMMMarketability SSSSustainability OOOOutreach/dissemination 62

63. TCEQ Regulations  Regulatory status of development-wide RWH strategy  Rules under consideration  Rules for backup supply strategies  Rule interpretations for RWH systems that are public water supply systems 63

64. Regulatory Status?  Building-scale RWH systems currently unregulated  Would it be a “public water supply system” if: Platted as THE water supply system the development? Platted as THE water supply system the development? Collective O&M of all RWH systems? Collective O&M of all RWH systems? Collective arrangements for backup supply? Collective arrangements for backup supply? 64

65. Would this cause the TCEQ to consider building-scale RWH a “public water supply system?” 65

66. Current understanding of TCEQ’s position  Building-scale RWH system to remain unregulated  Regulations being developed for RWH systems with connection to public water supply system on property  Regulatory status of tanker truck backup supply system needs clarification 66

67. Rule Interpretations for RWH that ARE Public Water Supply Systems village centers, churches, community halls 67

68. Public Water Supply Systems Rule Interpretations for RWH ChlorinationVS UV disinfection unit 68

69. Are these practices approved for building-scale systems? What would be the testing and reporting requirements? Would they be affordable? 69

70. County-level Governance Through Platting Requirements Rainwater Harvesting as THE development-wide water SYSTEM – what requirements would that generate? 70

71. County-level Governance Through Platting Requirements  “Water availability” standards  Water treatment standards  Backup supply standards 71

72. What does “water availability” require?  “Right-sizing” of roofprint and cistern  Backup supply system as determined by that system sizing 72

73. Who sets the standards for water availability? Commissioner’s Court? Developers? 73

74. Outreach to County Governments  “Chicken-or-egg” conundrum Developers aren’t requesting plat approval for this kind of water supply solution. Developers aren’t requesting plat approval for this kind of water supply solution. Therefore, no impetus for county governments to think through these matters. Therefore, no impetus for county governments to think through these matters.  Further outreach efforts are suggested: Surveys Surveys Seminars Seminars Focus group workshops Focus group workshops 74

75. Overview of Project Activities YYYYield-demand modeling BBBBackup supply options RRRRegulation and governance BBBBuilding design issues CCCCost effective analysis MMMMarketability SSSSustainability OOOOutreach/dissemination 75

76. “Right-Sized” RWH Facilities At Each Modeling Location 2-Person Occupancy4-Person Occupancy ModelingRoofprintCistern SizeRoofprintCistern Size Location(sq. ft.)(gallons)(sq. ft.)(gallons) Austin 2,500 15,000 4,500 35,000 Blanco 2,500 15,000 4,500 35,000 Boerne 2,500 15,000 4,500 35,000 Burnet 2,500 15,000 4,500 30,000 Dripping Springs 2,500 15,000 4,500 35,000 Fredericksburg 3,000 20,000 5,000 40,000 Menard 3,000 20,000 5,500 40,000 San Marcos 2,500 15,000 4,500 30,000 Wimberley 2,500 15,000 4,500 30,000 76

77. “Right-Sizing” the Roofprint and Cistern 77

78. The “Veranda Strategy”  Reduces solar load and air conditioning requirements  Creates outdoor living spaces 78

79. 79

80. Bladder-type cistern that could be placed under the veranda floor 80

81. Additional Roofprint with the “Veranda Strategy” 81

82. Need Hill Country RWH Vernacular Designs  Business opportunity for architects?  Design competition  Student design studio project 82

83. “Chicken or Egg” Again Developers need house designs that could implement rainwater harvesting systems. 83

84. Overview of Project Activities YYYYield-demand modeling BBBBackup supply options RRRRegulation and governance BBBBuilding design issues CCCCost effective analysis MMMMarketability SSSSustainability OOOOutreach/dissemination 84

85. Cost Effectiveness of RWH vs. Other Strategies  Compare global life-cycle costs  Other strategies to be evaluated: 85

86. Cost items for Building-scale RWH Strategy  First Costs “Extra” roofprint “Extra” roofprint Collection/first flush hardware Collection/first flush hardware Cistern Cistern Treatment system Treatment system Disinfection system Disinfection system Pump/pressurization system Pump/pressurization system  On-going Costs Power costs Power costs O&M, equipment replacement O&M, equipment replacement Backup water costs Backup water costs 86

87. Summary and Comparison Costs of Water Supply Options 87

88. Overview of Project Activities YYYYield-demand modeling BBBBackup supply options RRRRegulation and governance BBBBuilding design issues CCCCost effective analysis MMMMarketability SSSSustainability OOOOutreach/dissemination 88

89. Marketing Focus Group The marketing focus group included members of the following interest groups: Land developers Land developers Homebuilders Homebuilders Architects Architects Land planners and engineers Land planners and engineers Real estate brokers Real estate brokers Banker (home finance specialist) Banker (home finance specialist) Consumers (potential home buyers) Consumers (potential home buyers) 89

90. What determines Marketability? ASSURED backup supply available RWH-“friendly” house designs Regulatory clarity Cost effective Readily available financing 90

91. The BIG ONE – Perception 91

92. “Conservation Ethic” 92 Will perception about “deprivation” deter developers from adopting RWH?

93. Education Key Factor for Marketability Photo courtesy of ARCSA: http://www.arcsa.org/content.asp?contentid=194 93

94. Overview of Project Activities YYYYield-demand modeling BBBBackup supply options RRRRegulation and governance BBBBuilding design issues CCCCost effective analysis MMMMarketability SSSSustainability OOOOutreach/dissemination 94

95. Sustainability of Development “Development lives mainly on water falling on it.” 95

96. Long-Distance Water Importation Photo courtesy of California Department of Water Resources 96

97. “Conservation Development” The Pattern Favored for the Hill Country 97

98. Hydrologic Sustainability Does RWH “rob” water from streams and aquifers? World Birding Center Headquarters, photo courtesy Lake Flato Architects 98

99. Hydrologic Sustainability Strategy for analysis: Strategy for analysis: Rainfall-runoff response of undeveloped site Rainfall-runoff response of undeveloped site Rainfall-runoff response of developed site, no RWH Rainfall-runoff response of developed site, no RWH Rainfall-runoff response of developed site with RWH Rainfall-runoff response of developed site with RWH 99

100. Outcomes of Hydrologic Modeling  Rainwater harvesting will NOT result in decreased levels of runoff from the finished development in comparison with the land in its “raw” state.  The addition of impervious cover other than roofs – i.e., streets and driveways – and land alterations – e.g., improved landscaping, drainage structures – will result in a higher runoff rate from all non-roof areas, more than making up for what is captured into rainwater cisterns. 100

101. Hydrologic Sustainability 101

102. Hydrologic Sustainability RWH off rooftops in a development would improve the hydrological integrity of the developed property. 102

103. For more information: Texas Water Development Board www.twdb.texas.gov/innovativewater/rainwater/ Meadows Center for Water and the Environment Texas State University www.rsihillcountrywater.org/rainwater-harvesting/ David Venhuizen, P.E. venhuizen-ww.com For more information: Texas Water Development Board www.twdb.texas.gov/innovativewater/rainwater/ Meadows Center for Water and the Environment Texas State University www.rsihillcountrywater.org/rainwater-harvesting/ David Venhuizen, P.E. venhuizen-ww.com venhuizen-ww.com 103