rapid assessment method brian smith water quality/biology environmental specialist brian.smith...
Post on 19-Dec-2015
215 views
TRANSCRIPT
Rapid Assessment Method
Brian Smith
Water Quality/Biology Environmental Specialist brian.smith @fhwa.dot.gov
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
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
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
Rapid Assessment
Incorporates many HGM concepts
Follows qualitative, rule-based modelingRules replace equations or quantitative
dataDraws on and synthesizes what is known
without introducing unknown parameters
Expedient, less costly, less time consuming
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
Wetlands
Travel Patterns Overlaid With Sewered Areas
Listed Species Habitat, Sewered Areas and Travel Patterns
“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 SubjectivityConsider Proximity of Development
Consider adjacent land use and associated interrelationships
Rapid Assessment Objectives
Wetland evaluation methodRapidEconomicalRepeatable
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
Stay away from:
Using too many attributes and indicators
Having too many categories
Subjectivity
Frivolous weighting schemes
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
Steps in the Procedure
1. Describe the Region (including HGM or wetland classes)
2. Develop a Profile for Each HGM or Wetland Class
3. Develop a List of Functions4. Develop a Functional Profile for Each HGM
Class5. List Relevant & Appropriate Variables for
Each Function6. Describe Each of the Variables
Steps in the Procedure
7. Prepare Rationale for Model Development
8. Develop an Inventory Sheet
9. Develop a Model for Each Function
10. Modify Procedure for Other Regions
11. Apply Procedure to Case Studies in Several Regions
12. Fine Tune Procedure Based on Case Study Results
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)
Technical Team
Defines:HGM classesIdentifies reference criteria
Identifies reference
standard reference
standard subset
Defines:What is functional and dysfunction?Should have local knowledgeWhat attributes that can be screened using GIS or aerial photography?
Useful GIS Information
2-ft contourHydric soilsClosed depressionsUSGS blue-line streamsShape files of recorded floods 2-yr, 5-yr, 10-yr, 20-yr,
100-yr
Existing info from land managers
GeomorphologyRegeneration distanceNRCS farmed wetlandsStream buffersPublic landsPermanent water Landscape factors
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
High Quality and High Value Wetlands
High Quality Habitat
Habitat and Floristic Quality/Diversity Irreplaceable Unmitigatable High state/local
inventory score
High Functional Value
Functional value Several beneficial
functions provided
Initial Screening Process
Existing inventories (state, county)
Aerial photo interpretation and scoring Hydric soilsSize, shape characteristicsPhysical Attributes and IndicatorsDependent on GIS, photo, map resolution Positive and negative
Knowledge of local experts
Initial Screening Process
Purpose:
High functional vs. low functional
Indicators of Dysfunction
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
Aquatic HabitatLAKES
STREAMS
Water Quality and Stormwater Storage Functions
Three mitigating functions present:1. Sediment and toxicant retention2. Nutrient removal and
transformation3. Stormwater Storage/Hydrologic
Stabilization4. Or critical size or juxtaposition in
the landscape wrt to downstream resources
Water Quality Mitigating Functions
Shoreline and streambank stabilizationFlowing water present
Sediment and toxicant retention
Nutrient removal and transformation
Stormwater Storage/Hydrologic Stabilization
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
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
> 5 acres and 50% outside floodplain
Non-riparian
Minimal outlet alteration
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)
Watershed Setting
Advanced Identification of Wetlands (USEPA, USACE, local agencies)
GIS screening tools
Aerial photographs
Field investigation
Watershed SettingMany 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
Watershed SettingAdvanced 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 acresApprox. 10% of wetlands had notable watershed functions
Your Project??
Functional ModelDiversity of Wetland Vegetation
Variables
Plant species diversity
Wetland juxtaposition
Structure
Conditions
High, medium, low
Connected isolated
Pattern
Example indicators (habitat diversity)
Database
General Condition
Size
Location
Disturbance
Functional score
Known Attributes
Quality indicators
Functional indicators
Imperilment
Vulnerability
Viability
Thank you
Brian Smith
Biology/Water Quality Specialist
FHWA – National Resource Center