Rapid Assessment Method

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Rapid Assessment Method

• Brian Smith
• Water Quality/Biology Environmental Specialist
  brian.smith _at_fhwa.dot.gov

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National Wetland Mitigation Banking Study
Technical and Procedural Support to
Mitigation Banking Guidance (Dec 1995)
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Rapid Assessment Method

• Examples
• Minnesota Routine Assessment Method
• Montana Department of Transportation
• Rouge River Project (MI)
• Wetland Rapid Assessment Procedure (FL)
• McHenry County, Illinois
• Advanced Identification (ADID) Study
• Evaluation Methodology

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This Procedure is not HGM but

• Geomorphic setting
• Hydrology is a key factor
• Assigns wetlands to HGM subclass

• Reference and reference standard wetlands used
• Models based on data from reference wetlands

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HGM APPROACH

• Lacks landscape focus
• Costly to implement
• Guidebook testing
• Inconsistent
• Uncoordinated
• Depends on funding
• Variables based on indicators not processes

• Diagnostic not prescriptive
• Does not contribute to mitigation design
• No guarantees for success
• Hydrology, WL, native vegetation
• No structure for inserting success factors

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Rapid Assessment

• Incorporates many HGM concepts
• Follows qualitative, rule-based modeling
• Rules replace equations or quantitative data
• Draws on and synthesizes what is known without
  introducing unknown parameters
• Expedient, less costly, less time consuming

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Rapid Assessment

• Functional indicators of each function
• Functional indicators site variables
• Range of conditions variable conditions
• An index (functional index) generated for each
  function
• Indicates functional capacity
• Only compared within same HGM class and region

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Wetlands
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Travel Patterns Overlaid With Sewered Areas
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Listed Species Habitat, Sewered Areas and Travel
Patterns
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• The proximity of development may alter wetland
  functions and values. evaluation of the
  resource must consider adjacent land use and
  associated interrelationships.
• National Academy of Science (NAS)
• regarding wetland loss and compensation
• Reduce Subjectivity
• Consider Proximity of Development
• Consider adjacent land use and associated
  interrelationships

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Rapid Assessment Objectives

• Wetland evaluation method
• Rapid
• Economical
• Repeatable

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Rapid Assessment Objectives

• Meets needs of local regulatory agencies
• Identifies functions and values
• Incorporates some principles of HGM
• Considers spatial arrangements and scale
• Identifies human activities as part of the
  environment
• Enhance databases

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Stay away from

• Using too many attributes and indicators
• Having too many categories
• Subjectivity
• Frivolous weighting schemes

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GIS Themes

• Used as spatial templates to define areal
  hydrologic settings
• Identify Geomorphic Setting
• Indicates the fluvial environment (e.g. hydric
  soils)
• Landforms and landscapes
• Water source and hydrodynamics
• Direction of flow and strength of water movement
• Layers ranked and combined at a landscape scale
  to provide a relative assessment of wetland
  equivalence

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Steps in the Procedure

• Describe the Region (including HGM or wetland
  classes)
• Develop a Profile for Each HGM or Wetland Class
• Develop a List of Functions
• Develop a Functional Profile for Each HGM Class
• List Relevant Appropriate Variables for Each
  Function
• Describe Each of the Variables

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Steps in the Procedure

• Prepare Rationale for Model Development
• Develop an Inventory Sheet
• Develop a Model for Each Function
• Modify Procedure for Other Regions
• Apply Procedure to Case Studies in Several
  Regions
• Fine Tune Procedure Based on Case Study Results

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What should your assessment method do?

• Rank wetland functions and values?
• Assess interrelationships?
• Assess regional significance? (Mapping)
• Define watershed functions?
• Database integration
• Use good science (peer approved)

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Technical Team

• Defines
• HGM classes
• Identifies reference criteria
• Identifies
• reference standard
• reference standard subset

• Defines
• What is functional and dysfunction?
• Should have local knowledge
• What attributes that can be screened using GIS or
  aerial photography?

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Useful GIS Information

• 2-ft contour
• Hydric soils
• Closed depressions
• USGS blue-line streams
• Shape files of recorded floods
• 2-yr, 5-yr, 10-yr, 20-yr, 100-yr
• Existing info from land managers

• Geomorphology
• Regeneration distance
• NRCS farmed wetlands
• Stream buffers
• Public lands
• Permanent water
• Landscape factors

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Important Functions

• Biological/Habitat Functions
• Wildlife Habitat/Floristic Diversity
• Stream and Lake Aquatic Habitat

• Water Quality/ Stormwater Storage Functions
• Shoreline and streambank stabilization
• Sediment and toxicant retention
• Nutrient removal and transformation
• Stormwater storage and hydrologic stabilization

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High Quality and High Value Wetlands

• High Functional Value
• Functional value
• Several beneficial functions provided

• High Quality Habitat
• Habitat and Floristic Quality/Diversity
• Irreplaceable
• Unmitigatable
• High state/local inventory score

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Initial Screening Process

• Existing inventories (state, county)
• Aerial photo interpretation and scoring
• Hydric soils
• Size, shape characteristics
• Physical Attributes and Indicators
• Dependent on GIS, photo, map resolution
• Positive and negative
• Knowledge of local experts

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Initial Screening Process

• Purpose
• High functional vs. low functional
• Indicators of Dysfunction

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Wildlife Habitat and Floristic Quality/Diversity

• Attributes
• Drainage ditches (-)
• Excavation (-)
• Size (GIS) ()
• Physical intrusions and barriers (-)
• Surrounding land use (/-)
• Habitat structure ()
• Vegetative and open water interspersion

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Aquatic Habitat
LAKES
STREAMS
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Water Quality and Stormwater Storage Functions

• Three mitigating functions present
• Sediment and toxicant retention
• Nutrient removal and transformation
• Stormwater Storage/Hydrologic Stabilization
• Or critical size or juxtaposition in the
  landscape wrt to downstream resources

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Water Quality Mitigating Functions

• Shoreline and streambank stabilization
• Flowing water present
• Sediment and toxicant retention
• Nutrient removal and transformation
• Stormwater Storage/Hydrologic Stabilization

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GIS Screening

• Shoreline stabilization
• Quality of buffer vegetation
• Wetland adjacency
• Wetland buffer width

• Sediment and toxicant retention
• Size
• Upstream of valuable aquatic resource
• Minimal outlet alteration
• Erect persistent vegetation
• Sediment accretion present
• Occasional flooding or ponding

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GIS Screening

• Nutrient Removal/ Transformation
• Upstream of valuable aquatic resource
• Non-riparian
• Minimal outlet alteration
• Ground cover vegetation in a low velocity
  environment

• Stormwater Storage/ Hydrologic Stabilization
• gt 5 acres and 50 outside floodplain
• Non-riparian
• Minimal outlet alteration

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Watershed Setting

• wetland remnants of the development process may
  not constitute the best configuration of wetland
  type for a watershed
• has implications for the kind of wetland
  planning that might be required in some
  watersheds and mitigation practices in those
  watershed
• (NAS - Committee on Mitigating Wetland Losses)

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Watershed Setting

• Advanced Identification of Wetlands (USEPA,
  USACE, local agencies)
• GIS screening tools
• Aerial photographs
• Field investigation

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Watershed Setting

• Many wetland systems have been altered, severed,
  fragmented
• Juxtaposition
• Interrelationships
• Flow patterns
• Many wetlands not functioning in their historical
  (pre-settlement) context
• How critical were interrelationships?
• Our best guess must consider landscape

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Watershed Setting

• Advanced Identification of Wetlands
• 4 of total of wetlands in county designated as
  high habitat quality of biological functions
  (17,489 acres)
• 17,489 acres of high habitat quality accounted
  for 42 of wetland acres
• Approx. 10 of wetlands had notable watershed
  functions
• Your Project??

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Functional ModelDiversity of Wetland Vegetation

• Variables
• Plant species diversity
• Wetland juxtaposition
• Structure

• Conditions
• High, medium, low
• Connected ? isolated
• ? Pattern

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Example indicators (habitat diversity)
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Database

• General Condition
• Size
• Location
• Disturbance
• Functional score
• Known Attributes

• Quality indicators
• Functional indicators
• Imperilment
• Vulnerability
• Viability

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Thank you

• Brian Smith
• Biology/Water Quality Specialist
• FHWA National Resource Center