Rapid Assessment Method Brian Smith Water Quality/Biology Environmental Specialist
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 modeling Rules replace equations or quantitative data Draws 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 Subjectivity Consider Proximity of Development Consider adjacent land use and associated interrelationships
Rapid Assessment Objectives Wetland evaluation method Rapid Economical Repeatable
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 Functions 4. Develop a Functional Profile for Each HGM Class 5. List Relevant & Appropriate Variables for Each Function 6. 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 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?
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
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 soils Size, shape characteristics Physical Attributes and Indicators Dependent 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 Habitat LAKES STREAMS
Water Quality and Stormwater Storage Functions Three mitigating functions present: 1.Sediment and toxicant retention 2.Nutrient removal and transformation 3.Stormwater Storage/Hydrologic Stabilization 4.Or critical size or juxtaposition in the landscape wrt to downstream resources
Water Quality Mitigating Functions Shoreline and streambank stabilization Flowing 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 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
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??
Functional Model Diversity 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