Comprehensive
Benefit Analysis of
the Chesapeake
Bay TMDL
Presented by
Elena Besedin
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
Models
Water Quality
Aquatic Ecosystem
Fisheries Model
Models
Vegetation effects on air
Hydrological Models
Flood risk models
Human health risk
Monetization
approaches
Abt Associates | pg 2
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 3
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 4
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 5
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 6
Indirect TMDL Effects
Example BMPs
Non-Water Quality Effects


Land Management
–
–
–
–

Agricultural land retirement
Tree planting
Forest buffers
Grass buffers
–  in open space / vegetated areas
–  in the number of trees
–  in riparian habitat / wetlands

Agriculture
– Erosion control (buffer zones)
– Animal waste management

Urban Stormwater Management
–  in impervious cover
Hydrology
–
–
–
–
Natural area restoration
– Wetland restoration
– Stream restoration

Land

 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 7
Identifying and Evaluating
Ecosystem Services
Ecosystem 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 activities
Aesthetic (water clarity/color)
• Property values
• Scenic vistas
Nonuse
• Habitat preserving aquatic biodiversity
Land and Near Water Recreation
• Fishing and shellfishing
• Hunting (waterfowl and game)
• Birding
• Hiking/nature enjoyment
Aesthetic (landscape effects)
• Property values
• Scenic vistas
Education
• Wetlands/forest education centers
Nonuse
• Habitat preserving wildlife and plant
biodiversity
Abt Associates | pg 8
Identifying and Evaluating
Ecosystem Services (continued)
Ecosystem
Service Category
Regulating
Water Quality Changes
•
•
•
•
•
•
Nutrient cycling
Primary production
Hypoxia events
Ecosystem resilience
pH
Water Clarity
Ancillary BMP Services
Air
• Air pollutant releases (ammonia)
• Air pollutant removal by vegetation
• Carbon storage
• Reduction in air temperature volatility
Soil
• Erosion control
• Sediment retention
Hydrology
• Flood control
• Stream bank stabilization
• Stream channel protection
• Groundwater recharge
Water Quality
• Filtration/Nutrient removal (groundwater)
• Reduction in stream temperature volatility
Abt Associates | pg 9
Bringing the Pieces Together: Example
Framework for Estimating TMDL Benefits
Simplified representation showing only selected components of the analysis.
Abt Associates | pg 10
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 11
Human Health Effects from
Reduced Air Pollution (Example)
Population Distribution by
Age and Presence of
Sensitive Subgroups
For each subgroup and
baseline and postregulation:
Pollutant exposure
distribution
Adverse health effects
distribution
$
Monetary
Value of
Health
Effects
BenMap (EPA_OAQPS)
Abt Associates | pg 12
Flood Analysis Approach (Example)
Updated HAZUS-HM
Inventory in 2040
Channel/Floodplain assumptions in SWAT, Manning’s Equation
SWAT
Flows
Flood Hazard
(Flood
Frequency
Analysis)
Flood
Flows
Channel/Floodplain assumptions in SWAT
Flood Depth
Estimation
Flood Depths
NFRST
Flood Zone
Estimation
Floodplain Areas
per Census Block
Stream lines
Census Block
GIS Data
Flood Impacts
$
 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 13
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



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
Employment Effects
Regional Economic Impacts
– Input output models
Abt Associates | pg 14
Nonmarket Valuation
Water Quality
Landscape


Water-based recreation
–
–
–

Human health (e.g., exposure to pathogens
in shellfish, drinking water or while
swimming)
–
–
–

Cost of illness
SP studies
Averting behavior
Aesthetic
–
–
–

Recreational demand models
Stated preference (SP) studies
Hedonic studies
Hedonic property
SP studies
Recreational demand
Nonuse values (aquatic life support,
biodiversity, overall ecosystem health and
resilience)
–
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
Stated preference studies
Abt Associates | pg 15
Nonmarket valuation
Air
Hydrology


Human health
– Exposure to criteria pollutants
(mortality and morbidity)
– SP studies
• Cost of illness
• Stated preference studies (BT)
– Exposure to extreme temperature
(mortality)
– Hedonic property models

Carbon sequestration
• Social Cost of Carbon (SCC)
Groundwater protection
– SP studies
– Averting behavior
• SP studies

Flooding (value of reduced flood
risk)

Stream channel protection
– SP studies
– Hedonic property models
Abt Associates | pg 16
Value of Ancillary Services from Urban BMPs for
Chesapeake Bay Watershed
EPA/ORD analysis, 2011
Abt Associates | pg 17
Example Cost-Effectiveness of BMPs
with and without Ancillary Benefits
Abt Associates | pg 18
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
Abt Associates | pg 19