Water Conservation &Reuse Strategies for Southern California

Rosalind Haselbeck , PhD, LEED APBuilding Green Futures Inc.

LUNCH + LEED

July 15, 2010

Learning Objectives

1. Apply the historical context to our current water crises, both globally and here in San Diego.

2. Identify strategies to reduce indoor water use.3. Discuss the basic features of a rainwater

harvesting system including benefits, components, and estimating supply and demand.

4. Develop an outside water usage and conservation strategy.

5. Identify resources to support water conservation and rainwater/graywater systems.

www.zmescience.com/.../2009/08/water_b.jpg

Historical Context

• How We Use Water

• The Water Cycle and Urbanization

• Water Usage in San Diego

Water FootprintItem Gallons to

produce

Glass of Milk 52

Cup of Coffee 37

1 Apple 19

Cotton T shirt 530

Hamburger 635

Meat-based diet 1320/day

Vegetarian diet 687/day

Source: United Nations Development Report, 2006

Location Water useGPC/day

San Diego 164

US average 152

Japan 99

Germany 51

Nigeria 10

Uganda 4

Water scarcity <13

Water Usage

Source: SDWA Annual Report 2009

How We Use Water

• “Reducing potable water demand by 10% could save approximately 300 billion kilowatthours of energy each year” (Michael Nicklas, Rainwater, High Performance Buildings, Summer 2008).

• Use of potable water– Single vs. multi-use– Need for potable water indoor applications– According to the EPA, 80% of indoor use doesn’t

require potable (Municipal Handbook Rainwater Harvesting Policies, 12/08)

Water Run-off: developed vs. natural

Source: http://www.coastal.ca.gov/nps/watercyclefacts.pdf

Source: http://www.epa.gov/volunteer/stream/vms21.html

History of Water Usage in San Diego

Old Mission Dam; completed 1815 San Vicente reservoir; 1947

Source: San Diego County Water Authority(http://www.sdcwa.org/about/who-history.phtml)

Source: SDWA Annual Report 2009

“Water conservation is the cheapest new source of water”--SDWA, ‘07

Indoor Water Usage

• Water usage and fixture choices

• Water reuse for indoor applications

• LEED credits for Water Efficiency

• Standards for indoor rainwater usage

Source: American Waterworks Association Research Foundation (AWWARF) Residential End Uses of Water, Denver, CO; 1999

Annual Indoor Water UsageVery High Efficiencyf vs. Standard**

Fixture Average # uses per day per person*

Typicalfixture (gal or min)**

Gallonsper person per day

Gallonsper yearfamily of 4

Very hi efficiency fixture(gal or min)f

Gallonsper person per day

Gallons per yearfamily of 4

Toilet 4 1.6 gpf 6.4 9,344 1.1 gpf 5.2 7,592

Lavatoryfaucet

5 2.2 gpm0.5 min

5.5 8,030 1.5 gpm0.5 min

3.75 5,475

Shower 1 2.5 gpm6.3 min

15.75 22,995 1.75 gpm6.3 min

12.6 18,396

Clotheswasher

7 per wkFamily*

55 gal* 20,020 (25 gal) 9,125

Total 60,389 42,413

* Source: http://www.csgnetwork.com/waterusagecalc.html** Source: EPAct 1992; http://www.epa.gov/watersense/docs/matrix508.pdff Source: LEED-H Reference Guide WE 3.2; 2008

WE (min 3 pts) Credit Points

WE 1: Water Reuse5 points max

1.1 Rainwater Harvesting SystemAnd/or

4 points outdoor + indoor (>50% roof)

1.2 Graywater 1 point

OR1.3 Municipal Recycled Water

3 pts max if use instead of1.1-1.2

WE 2: Irrigation 2.1 Hi-efficiency 3 points max

4 points max 2.2 3rd party 1 point max

OR 2.3 Reduce irrigation demand

4 points max

WE 3: Indoor Water Usage

3.1 Hi-efficiencyfixtures/fittings

3 points if all fixtures

6 points max 3.2 Very hi-efficiency 6 points max

WE Credits for LEED-Homes: Maximum 15 points possible

Source: USGBC LEED for Homes Rating System, 2008

WE (min 3 pts) Credit Points

WE 1: Water Efficient Landscaping4 points max

1.1 Use 50% reduction: rainwater, graywater, or recycled municipal

2 points

OR 1.2 NO potable water or NO irrigation

4 points

WE 2: InnovativeWastewater2 points max

Reduce potable water for sewage conveyance or treat to tertiary (50%)

2 points

WE 3: Water use reduction (all indoor fixtures; not irrigation)

3.1 Use 30% Reduction (20% is prerequisite v 3.0)

2 points

4 points max 3.2 Use 35% reduction adds 1 point

3.3 Use 40% reduction adds 1 point

WE Credits for LEED-NC: Maximum 10 points possible

Source: USGBC LEED for New Construction Rating System, 2009

Example Commercial BuildingIndoor Rainwater Application (WE 2 Option 1; LEED-NC v 3.0)

Source: Building Green Futures (www.buildinggreenfutures.com)

http://www.sloanvalve.com

CA Dual Plumbing Code 2010

• Air gap required (recycled and potable)

• Water disinfected to tertiary recycled standard (CA Dept Public Health; filtration/chlorine)

• Allowed structures specified by 13553 Water Code (no single-family residential)

Source: California Plumbing Code Chapter 16A-Part II, 2010

Non-potable Indoor Use of Rainwater*

• Gutters & tank inlet with debris screen

• First flush/roof washer (first 10 gallons)

• Return elbow or calming inlet

• UV-resistant for above-ground

• Air gap or back-flow assembly (municipal vs. rainwater)

• Label pipes and fixtures

• Disinfection is not required

* Code Guide for Rainwater Harvesting; City of Portland for one and two family dwellings, 2001

Rainwater Harvesting Overview

• Benefits of rainwater harvesting

• System components

• Water-harvesting earthworks

• Estimating supply & demand to size tanks

Benefits of Rainwater Harvesting

COMMUNITY• Storm water management (reduces run off to

storm drains)• Reduces summer peak water demands

(conserves water)

INDIVIDUAL• Superior water for irrigation (soft, non-alkaline)• Lower water bills (1st tier)• Possible rebates/incentives (AB 1834)

Components of Rainwater Harvesting for Irrigation

Roof catchment area

Gutters & downspout

StorageTank

OverflowPump

To drip system/hose

Source: Building Green Futures (www.buildinggreenfutures.com)

Above-ground Tanks

Source: RainHarvest Systems

Source: BH Tanks Inc. Source: Bushman Tanks USA

Source: Tankworks Australia

Below-ground Tanks

Source: Graf Rainwater Tanks

Source: Rainwater Collection Solutions

Source: Xerxes Fiberglass Tanks

Source: Atlantis Water Management

Using Earthworks

Source: Building Green Futures (www.buildinggreenfutures.com)

Landscape Features that Manage Stormwater

Source: EncinitasStormwaterManual, 2009

Photograph: City of Encinitas, Roadside GrassCrete parking

Source: SD County LID manual, 2007

Sustainable Water Management

Source: Building Green Futures (www.buildinggreenfutures.com)

Sizing a Rainwater Tank based on Supply & Demand

Basic formula to calculate monthly or annual collection

volume in gallons:

SUPPLY (gallons) = Catchment Area (ft2) X Rainfall (ft)

X Runoff Coefficient X 7.48 gallons/ft3

Note: Runoff coefficient = 0.9 for a typical roof

Example scenario: a 2,000ft2 building:

2000ft2 x 0.83ft/yr x 90% x 7.48 gal/ft3 =

11,175 gallons per year!!

Basic formula to calculate monthly or annual irrigation

demand in gallons:

DEMAND (gallons) = (ETo X Plant Factor) X Area (ft2)

X 7.48 gallons/ft3

Estimating Supply & Demand

Source: Building Green Futures (www.buildinggreenfutures.com)

Outdoor Water Usage

• Drought-tolerant and native plant choices(and soil/mulch)

• Brief introduction to gray water for irrigation

• Rainwater Harvesting Design Strategies(for San Diego County)

• Example projects

Graywater Code for California

• Ch 16A “Nonpotable Water Reuse Systems” added to 2007 California plumbing code August 4, 2009

• 1603A.1.1 Clothes Washer System and/or Single Fixture System: May be installed without a permit if in compliance

• May not result in ponding or run-off

• Design directs to irrigation and contained on site

• If released above-ground requires >/= 2” mulch

Graywater System to Mulch Basins

www.yourhome.gov.au/technical/fs74.html

Characteristics of Drought-tolerant Plants

Source: Building Green Futures (www.buildinggreenfutures.com)

Resources for Drought-Tolerant and Native Plants

• Sunset Western Garden Book by Editors of Sunset Books and K. N. Brenzel; watering designation 1 or 2

• San Diego County Native Plants by James Lightner(2006, San Diego Flora)

• http://www.water.ca.gov/wateruseefficiency/docs/wucols00.pdf Water Use Classification of Landscape Species (University of California Cooperative Extension)

• http://www.bewaterwise.com/knowledge01.htmlCalifornia Friendly Garden resource (from MWD)

• http://www.thegarden.org/ Water conservation Garden at Cuyamaca College; bookshop & classes

Project 1: An Above-ground System with a 550 gallon tank

Source: Building Green Futures (www.buildinggreenfutures.com)

Project 2: An Above-ground System with (2) 2,000 gallon tanks and French drains to landscape

Source: Building Green Futures (www.buildinggreenfutures.com)

Project 3: a Rainwater Pillow

Source: Building Green Futures (www.buildinggreenfutures.com)

Source: Building Green Futures (www.buildinggreenfutures.com)

Project 4: A Modular Underground Storage System

Source: Building Green Futures (www.buildinggreenfutures.com)

Source: Building Green Futures (www.buildinggreenfutures.com)

WE (min 3 pts) Credit Points Project item

WE 1: Water Reuse5 points max

1.1 Rainwater Harvesting SystemAnd/or

3 points outdoor1 point indoor

2 x 1700 gallon cisterns for irrigation only = 3

1.2 Graywater 1 point Clothes washer = 1

OR1.3 Municipal Recycled Water

3 pts max if use instead of1.1-1.2

WE 2: Irrigation 2.1 Hi-efficiency 3 points max

4 points max 2.2 3rd party 1 point max

OR 2.3 Reduce irrigation demand

4 points max

WE 3: Indoor Water Usage

3.1 Hi-efficiencyfixtures/fittings

3 points if all fixtures All fixtures meet standards = 3

6 points max 3.2 Very hi-efficiency (6 points max) TOTAL = 7

System size = Harvest area/Total Roof AreaStorage capacity = 0.62 gal/ft3 x Harvest areaTherefore 2,000 ft2 roof area min capacity = 620 gallons; max = 12,000 gallons

WE Credits for LEED-Homes: Maximum 15 points possible

Project 5: Rainwater Harvesting at NC Schools: indoor and

outdoor usage

Diagrams and Photo Courtesy of Innovative Design (Raleigh, NC)

Resources

• http://www.sandiego.gov/water/conservation

Rainwater harvesting information; residential water surveys (free)

• http://www.bewaterwise.com ; Rebates and incentives (So Cal Metropolitan Water District)

• http://socalwatersmart.com/index.php; Rebates/incentives

• http://www.harvesth2o.com/ ; Online rainwater harvesting community

• http://www.arcsa.org/Rainwater-10-09.pdf; Rainwater Catchment Standards ARCSA and ASPE

Resources; continued• http://www.epa.gov/npdes/pubs/gi_municha

ndbook_harvesting.pdf; EPA Rainwater Harvesting Guidelines

• http://www.whollyh2o.org; California’s Integrated Water Reuse Management Center

• http://www.h2ouse.org; California’s Urban Water Conservation Council

• http://www.oasisdesign.net/greywater/law/california/; California Graywater Policy Center

• Rainwater Harvesting for Drylands vol 1-3 by Brad Lancaster, Rainsource Press (2005-2011)

IF we combine low water use fixtures with water reuse indoors and outdoors

we can:

• Reduce wastewater and stormwater runoff

• Reduce use of potable water

• Increase water reuse

• Restore natural hydrologic cycle

• Preserve freshwater for future generations

“."

Contact:Rosalind Haselbeck, PhD, LEED AP(619) 300-7114rosalind@buildinggreenfutures.com