Virginia Rainwater Harvesting Manual 2007 VVIIRRGGIINNIIAA RRAAIINNWWAATTEERR HHAARRVVEESSTTIINNGG MMAANNUUAALL A comprehensive guide to examining, designing and maintaining rainwater harvesting systems to abate stormwater runoff. The Cabell Brand Center The Cabell Brand Center 2007 1 Salem, VA www.cabellbrandcenter.org Virginia Rainwater Harvesting Manual 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, Nickolas J. Sojka, DVM and Cabell Brand. The Cabell Brand Center i Salem, VA www.cabellbrandcenter.org 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 ........................................................................................................ 10 Virginia Rainwater Harvesting Application..................................................n .................11 Environment ..................................................................................................................11 Economic.......................................................................................................................12 Taxes ..........................................................................................................................12 Cost of water ..............................................................................................................13 LEED Certification ........................................................................................................ 14 Low Impact Development .............................................................................................14 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 ...........................................................................................30 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 i Salem, VA www.cabellbrandcenter.org Virginia Rainwater Harvesting Manual 2007 Residential .....................................................................................................................42 Agricultural....................................................................................................................51 Links..................................................s .............................................................................53 The Cabell Brand Center ii 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. 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: Biofilm 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 iii 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 5: Industrial rainfall catchment (gallons) ................................................................29