Comprehensive Benefit Analysis of the Chesapeake Bay TMDL

Presented by Elena Besedin

Abt Associates | pg 2

Comprehensive Benefit Analysis of the Chesapeake Bay TMDL

BMP Effects

Direct Effects Nutrient load Sediment Load

Indirect Effects Air pollutant release Vegetation/open space

Hydrology

ModelsWater Quality

Aquatic EcosystemFisheries Model

ModelsVegetation effects on air

Hydrological ModelsFlood risk models

Human health risk

Monetization approaches

Abt Associates | pg 3

Benefits of the Chesapeake Bay TMDL: Previous Analyses

Benefit categories included in previous analyses (M. Cropper and W. Isaac, 2011)

– Commercial fishing

– Water-based recreation (fishing, swimming, boating

– Property values

– Nonuse values

Ancillary benefit categories (EPA/ORD)

– Carbon sequestration

– Air pollutant removal (screening level)

Abt Associates | pg 4

Comprehensive Analysis of the Chesapeake Bay TMDL Including additional benefit categories

– Modeling additional ecological effects and ecosystem services provided by Chesapeake Bay and BMPs to reduce nutrient loadings beyond those accounted for in previous analyses

Modeling additional market effects Estimating potential employment effects Including additional services and other economic effects in

benefit-cost analysis

– Accounting for costs and benefits based on TMDL implementation timeline

• Phased controls: 60% of actions by 2017; 100% by 2025

• Potential to evaluate costs and benefits over implementation timeline

– Potential for optimization of BMPs accounting for additional ecosystem service benefits

Abt Associates | pg 5

Direct TMDL Effects: Nutrient and Sediment Load Reductions

Nutrient reductions impacts: Reduced Algal Blooms

– Increased nutrient retention, benthic infauna, community composition, increased oxygen availability, increased water clarity and light transmission

Increased Oxygen Availability– Direct effects on frequency of hypoxic events,

macroinfaunal diversity and biomass, increased bivalve populations and filtration rates, nutrient cycling, fisheries productivity

Decreased Acidification– Population and growth effects of major calcifiers,

altered vital rates, community composition

Nutrients

Algae Turbidity

O2

Light Benthic

Production

Redox Nitrification

Uptake Suspension

Nutrient Recycling

Abt Associates | pg 6

Direct TMDL Effects: Nutrient and Sediment Load Reductions

Sediment reductions improve many factors: Increased Water Clarity

– Direct effects on benthic primary production, macroinfaunal diversity and biomass, shift in relative importance of demersal (increase) and pelagic (decrease) food webs

Increased Submerged Aquatic Vegetation (SAV) Area– Positive feedback with particle trapping and

sediment binding, reduced efflux of sediment nutrients, increased nutrient assimilation, increased oxygen production

Nutrients

Algae Turbidity

O2

Light Benthic

Production

Redox Nitrification

Uptake Suspension

Nutrient Recycling

Abt Associates | pg 7

Indirect TMDL Effects

Example BMPs Land Management

– Agricultural land retirement – Tree planting – Forest buffers – Grass buffers

Natural area restoration– Wetland restoration– Stream restoration

Agriculture– Erosion control (buffer zones)– Animal waste management

Urban Stormwater Management – in impervious cover

Non-Water Quality Effects Land

– in open space / vegetated areas– in the number of trees– in riparian habitat / wetlands

Hydrology – in on-site water storage– in groundwater recharge– in flood risk– stream channel protection

Air effects– reduced ammonia releases – air pollutant removal by vegetation– in temperature extremes

Abt Associates | pg 8

Identifying and Evaluating Ecosystem ServicesEcosystem Service

Category Water Quality Changes Ancillary BMP Services

Provisioning • Habitat for fish/shellfish consumed by humans

• Drinking water supply• Agricultural and industrial water supply• Navigation

• Riparian/terrestrial habitat for fish and game consumed by humans

• Provision of wood and other forest products• Drinking water supply (groundwater)

Cultural Water-based Recreation• Swimming• Fishing• Hunting• Boating• Near water activitiesAesthetic (water clarity/color)• Property values • Scenic vistasNonuse• Habitat preserving aquatic biodiversity

Land and Near Water Recreation• Fishing and shellfishing• Hunting (waterfowl and game)• Birding• Hiking/nature enjoymentAesthetic (landscape effects)• Property values • Scenic vistasEducation• Wetlands/forest education centersNonuse• Habitat preserving wildlife and plant

biodiversity

Abt Associates | pg 9

Identifying and Evaluating Ecosystem Services (continued)

Ecosystem Service Category Water Quality Changes Ancillary BMP Services

Regulating • Nutrient cycling• Primary production• Hypoxia events• Ecosystem resilience• pH• Water Clarity

Air• Air pollutant releases (ammonia)• Air pollutant removal by vegetation• Carbon storage• Reduction in air temperature volatilitySoil• Erosion control• Sediment retentionHydrology• Flood control• Stream bank stabilization• Stream channel protection• Groundwater rechargeWater Quality• Filtration/Nutrient removal (groundwater)• Reduction in stream temperature volatility

Abt Associates | pg 10

Bringing the Pieces Together: Example Framework for Estimating TMDL Benefits

Simplified representation showing only selected components of the analysis.

Abt Associates | pg 11

Effects of Increased Vegetation: i-Tree Model, US Forestry Service

i-Tree is a peer-reviewed model developed by the USFS– Estimates services from trees and shrubs– Use field data or GIS layers for tree canopy and impervious surface

Air Pollution Removal (PM10, PM2.5, NO2, SO2, CO, O3)– Pollution removal per unit of tree canopy based on local conditions– Can be converted to changes in concentrations

Carbon Sequestration and Storage– Sequestration and storage per unit of tree canopy

Energy Savings– Shading and windbreak savings based on tree placement

Can be supplemented with data for other vegetation types

Abt Associates | pg 12

Human Health Effects from Reduced Air Pollution (Example)

$Monetary Value of Health Effects

For each subgroup and baseline and post-

regulation:

Pollutant exposure distribution

Adverse health effects distribution

Population Distribution by Age and Presence of Sensitive Subgroups

BenMap (EPA_OAQPS)

Abt Associates | pg 13

Flood Analysis Approach (Example)

Channel/Floodplain assumptions in SWAT, Manning’s Equation

Flood Depths

SWAT Flood Zone Estimation

NFRST

GIS Data

Flood Hazard (Flood

Frequency Analysis)

Flood Depth Estimation

Flows Flood Flows

Floodplain Areas per Census Block

Stream lines Census Block

Channel/Floodplain assumptions in SWAT

Flood Impacts

Updated HAZUS-HM Inventory in 2040

SWAT: Soil and Water Assessment Tool developed by USDA HAZUS-MH: Hazards U.S. Multi-Hazard (HAZUS-MH) Tool developed by FEMA NFRST: National Flood Risk Screening Tool developed by Abt Associates

$

Abt Associates | pg 14

Market-based Approaches

Water Quality – Commercial fish/shellfish harvest– Drinking water treatment– Reservoir dredging – Navigational waterways dredging– Agricultural/industrial water supply

Air – Electricity savings– Technology alternatives to carbon

sequestration– Technology alternatives to air

pollutant removal Employment Effects Regional Economic Impacts

– Input output models

Hydrological Benefits– Flood damages– Groundwater quantity – Drinking water treatment

(groundwater)– Avoided cost of infrastructure

maintenance and expansion– Avoided cost of stream

restoration– Water storage for beneficial use

Abt Associates | pg 15

Nonmarket Valuation

Water Quality Water-based recreation

– Recreational demand models– Stated preference (SP) studies– Hedonic studies

Human health (e.g., exposure to pathogens in shellfish, drinking water or while swimming)

– Cost of illness– SP studies– Averting behavior

Aesthetic– Hedonic property– SP studies– Recreational demand

Nonuse values (aquatic life support, biodiversity, overall ecosystem health and resilience)

– Stated preference studies

Landscape Land (including wetlands)

– Land-based recreation• Recreational demand models• SP studies• Hedonic studies

– Aesthetic• Hedonic property• SP studies• Recreational demand

– Nonuse (wildlife habitat, biodiversity)

• SP studies

Abt Associates | pg 16

Nonmarket valuation

Air Human health

– Exposure to criteria pollutants (mortality and morbidity)

• Cost of illness• Stated preference studies (BT)

– Exposure to extreme temperature (mortality)

• SP studies

Carbon sequestration• Social Cost of Carbon (SCC)

Hydrology Flooding (value of reduced flood

risk)– SP studies– Hedonic property models

Groundwater protection– SP studies– Averting behavior

Stream channel protection– SP studies– Hedonic property models

Abt Associates | pg 17

Value of Ancillary Services from Urban BMPs for Chesapeake Bay Watershed

EPA/ORD analysis, 2011

Abt Associates | pg 18

Example Cost-Effectiveness of BMPs with and without Ancillary Benefits

Abt Associates | pg 19

Challenges, Gaps, Overlaps Quantification

– Lack of data or models to estimate ecological improvements (e.g., ecosystem resilience, stream channel stabilization)

– Some beneficial effects are omitted from the water quality modeling step (e.g., pathogens)

– Timeline for TMDL implementation

Monetization

– Linking ecological and economic endpoints

– Selecting ecological metrics that provide an accurate representation of ecosystem change

Measurable Comprehensive

Interpretable Applicable

– Potential overlapping and double counting of benefits

Property value change vs. recreational benefits

Property value change from improved landscape vs. water quality

– Capturing multi-media effects

Selecting an optimal set of BMPs: cost-benefit optimization framework