Calculation of the Environmental Benefits of Water Conservation BMP’s

CUWCC WorkshopsCUWCC WorkshopsSeptember 20-21 2006September 20-21 2006

Katie Coughlin, Ph. D.Katie Coughlin, Ph. D.Lawrence Berkeley National LabLawrence Berkeley National Lab

kcoughlin@lbl.govkcoughlin@lbl.gov

• LBNL Team

• Robert Van Buskirk

• Camilla Dunham-Whitehead

• Peter Chan

• Chris Bolduc

• UC Berkeley

•Michael Hanemann

Outline

• Conceptual Discussion• Definition of environmental benefits as an avoided cost

• Assumptions and constraints imposed by the modeling framework

• Ecological impacts and environmental values

• Model Application• Model organization and output

• Model input and interaction with the Avoided Cost model

• Example Calculations

• Questions and Discussion

Conceptual Discussion:Definition of environmental benefits as an avoided cost

• Calculate value in $/volume of environmental benefits of reduced water use

• The environmental benefit (EB) valuations can then be included in the cost-

benefit analysis of water conservation BMP’s

• Look at direct benefits of reduced raw water withdrawals which are not already

accounted for in other environmental programs

• Two exceptions: avoided cost of waste-water treatment for urban run-off;

environmental benefits of reduced energy use for system operations

• Like all avoided costs, this value is hypothetical, i.e. one must make numerous

assumptions about the future

• Philosophical issues related to monetization of environmental impacts are not

part of this project

Conceptual Discussion:Assumptions and constraints

• Requirements for this project include:— User inputs annual or seasonal water savings; no environmental data required— Model should cover all of CA and be “generic”— Compatibility with AC model— No double counting— Use data from literature reviews— Allow users to modify all default data values

• These impose constraints on the model:— Use annual average environmental data— Benefits are product of environmental impact and economic value— No accounting for water year type— Limited spatial resolution (hydrologic regions)— Doesn’t model system operations— Doesn’t consider water transfers

• Focus on accounting: all regions, services and sources

• This type of integrated calculation has not been done before

Geographic resolutionCalWater 2.2 Hydrologic Regions

Code Region NameNC North Coast SF San Francisco BayCC Central CoastSC South CoastSR Sacramento RiverSJ San Joaquin RiverTL Tulare LakeNL North LahontanSL South LahontanCR Colorado River

Conceptual Discussion:Environmental (ecological) impacts

• EB=unit environmental impact * economic value per unit

• Ecological impacts are defined in terms of services: maintenance of fish populations; maintenance of wetlands; improved water quality

• UEI = fraction*(service per unit volume of water)

• Fraction = probability that a unit of water saved at a source will be used by a particular service

• Use the most basic, robust physical parameters to define the relationship between service and water availability

• Account for seasonal variation in water requirements

• Depends on water source type and location

Unit Environmental impacts

• Determine the relationship between environmental service and water availability

• Express as unit impact per acre-foot

• Multiply by fraction for this service to get net impact per unit of saved water

Water Savings

WatSav(month, year,source)

Unit EnvironmentalImpact by Service

UEI(month, source, ens)

CalculateEnvironmental

Impact

Assemble list ofimpacts for this

source

Water SourceCharacteristics

EnvironmentalService

ens

Water SourceLocation

SLoc

Water SourceType

SType

Conceptual Discussion:Economic values

• EB=unit environmental impact * economic value per unit

• Units are $/service unit

• Economic values can be market or non-market

• Market values exist in the form of prices paid for land acquired expressly to restore riparian or wetland habitat

• Non-market values are drawn from the available literature and focus primarily on recreational uses such as fishing

• Urban runoff: use wastewater treatment costs

• Energy benefits: use emissions permit prices

• No geographic variation

Data Sources

• Fish habitat (4.2.4)• Populations and Regional Distribution: NOAA-NMFS West Coast Salmon

Biological Review Team Report (2003) and Calfish www.calfish.org• Flow data: CADWR water plan• Economic values: BASES study; Sportfishing Values Database

www.indecon.com/fish/signin.asp

• Riparian habitat (4.2.2)• River data: California Rivers Assessment www.ice.ucdavis.edu/newcara• Flow fractions: DWR water plan• Species distributions: California Natural Diversity Database

www.dfg.ca.gov/whdab/html/cnddb.html• Evapotranspiration rates: CIMIS• Species water needs: California Native Plant Society www.cnps.org• Economic values: purchases for conservation and restoration

• Wetlands (4.2.3)• Flow fractions: DWR water• Water requirements: USBR-DWR CALSIM II demands data; LBNL (N. Quinn)

spreadsheet model• Economic values: purchases for conservation and restoration

Data Sources

• Reservoir and lake recreation (4.2.1)• Average seasonal storage: California Data Exchange Center www.cdec.org• Storage-area relation: USBR-DWR CALSIM II data

• Visitation rates, visitation elasticity, economic values: QED studies from 1980• Economic values: BASES study at www.indecon.com/fish/signin.asp • Interagency Ecological Program quarterly reports iep.water.ca.gov• California Natural Diversity Database www.dfg.ca.gov/whdab/html/cnddb.html• California Native Plant Society www.cnps.org

• San Francisco Bay Salinity (4.2.5)• Flow-salinity data: DWR Dayflow model • Species distributions: Interagency Ecological Program quarterly reports

iep.water.ca.gov• Salinity impacts: Kimmerer et al. studies• No economic value data

• Energy Benefits• User input of energy intensity and energy/emissions costs

• Urban runoff• User input of runoff fractions and wastewater treatment costs