VVIIRRGGIINNIIAA RRAAIINNWWAATTEERR HHAARRVVEESSTTIINNGG MMAANNUUAALL A comprehensive guide to examining, designing and maintaining rainwater harvesting systems to abate stormwater runoff. The Cabell Brand Center 2007 VIRGINIA RAINWATER HARVESTING MANUAL Compiled by The Cabell Brand Center August 2007 Contributing Authors: Adrienne LaBranche, Hans-Otto Wack, Ph.D., David Crawford, Ed Crawford, and Cabell Brand Virginia Rainwater Harvesting Manual 2007 TABLE OF CONTENTS Acknowledgements .......................................................................................................... 1 Urgent Freshwater Problems..................................................s ..........................................2 The Trend .........................................................................................................................4 Future of Rainwater Harvesting ......................................................................................5 Systems............................................................................................................................5 Residential ....................................................................................................................6 Commercial ..................................................................................................................7 Industrial ......................................................................................................................8 Agricultural ..................................................................................................................9 Fire Suppression .......................................................................................................... 9 Virginia Rainwater Harvesting Application..................................................n .................10 Environment ..................................................................................................................10 Economic.......................................................................................................................11 Taxes ..........................................................................................................................11 Cost of water ..............................................................................................................12 LEED Certification ........................................................................................................13 Low Impact Development .............................................................................................13 Technical Standards and Rules ......................................................................................15 Components...................................................................................................................16 Plumbing ....................................................................................................................16 Tanks ..........................................................................................................................16 Conveyance systems ...................................................................................................18 Filters .........................................................................................................................19 Cleaning and Maintenance ........................................................................................21 Gutters: .............................................................................................................................. 21 Downspouts: ...................................................................................................................... 21 Filters:................................................................................................................................ 21 Tanks: ................................................................................................................................ 22 Design & Installation .................................................................................................22 Water Quality..................................................y ...............................................................23 Water quality standards .................................................................................................23 Oxygenation ..................................................................................................................24 Treating potable water...................................................................................................25 Factors affecting water quality ..................................................................................25 Sizing a System ..............................................................................................................27 Calculations ...................................................................................................................27 Virginia Rainfall Distribution........................................................................................28 Indoor Water Conservation ...........................................................................................29 Irrigation..................................................n .......................................................................31 Scheduling .....................................................................................................................31 Water Conservation Tips...............................................................................................32 Installation & Maintenance .......................................................................................32 Application .................................................................................................................32 References ......................................................................................................................34 Virginia Application & Case Studies..................................................s ...........................37 Commercial ...................................................................................................................38 The Cabell Brand Center iii Salem, VA www.cabellbrandcenter.org Virginia Rainwater Harvesting Manual 2007 Residential .....................................................................................................................41 Links..................................................s .............................................................................52 The Cabell Brand Center iv Salem, VA www.cabellbrandcenter.org Virginia Rainwater Harvesting Manual 2007 LIST OF FIGURES Fig. 1: Rainwater harvesting system ...................................................................................3 Fig. 2: Small residential nonpotable rainwater harvesting system...................................... 7 Fig. 3: Commercial or large residential above ground nonpotable rainwater harvesting system ..........................................................................................................................7 Fig. 4: Commercial or large residential below ground rainwater harvesting system..........8 Fig. 5: Siphonic roof drain ..................................................................................................8 Fig. 6: Collection pond with aeration fountain ...................................................................9 Fig. 7: Virginia counties regulated by Chesapeake Bay Preservation Act........................10 Fig. 8: Below ground tank.................................................................................................16 Fig. 9: Downspout filter ....................................................................................................19 Fig. 10: Vortex and downspout filters...............................................................................19 Fig. 11: Calming Inlet .......................................................................................................20 Fig. 12: Floating fine filter with pressure pump ...............................................................21 Fig. 13: Old and modern filter designs..............................................................................21 Fig. 14: Fine particulate matter and angled overflow pipe ............................................... 24 Fig. 15: Residential UV light potable water treatment...................................................... 25 Fig . 16: Average Virginia annual precipitation................................................................. 28 The Cabell Brand Center v Salem, VA www.cabellbrandcenter.org Virginia Rainwater Harvesting Manual 2007 LIST OF TABLES Table 1: Tank Comparison................................................................................................17 Table 2: Purification Options............................................................................................25 Table 3: Roofing material and associated contaminants................................................... 26 Table 4: Residential/Commercial rainfall catchment (gallons).........................................28 Table 5: Industrial rainfall catchment (gallons) ................................................................29 Table 6: Recommended tank size (gallons) ......................................................................29 Table 7: Water Saving Appliance Comparison................................................................