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