planning wetland restoration at the watershed level...planning wetland restoration and wetland...

Planning Wetland Restoration and

Wetland Conservation at the

Watershed and Local Levels

Ralph Tiner, USFWS Retired

ralphtiner83@gmail.com

and

Juli Crane and Glenn Westman,

Lake County (IL) Stormwater Management Commission

jcrane@lakecountyil.gov and gwestman@lakecountyil.gov

Two-part Presentation

◼ Introduction – Ralph Tiner

❑ What is Wetland Restoration?

❑ Outline Procedures to Identify:

◼ Potential Wetland Restoration Sites

◼ Likely Functions of These Sites

◼ Lost Functions for a Watershed (Historic Analysis)

◼ Problem areas where wetland restoration may help reduce problem

◼ Example of use of techniques for local wetland protection –

❑ Juli Crane and Glenn Westman

What is wetland restoration?

◼ The return of a wetland and its functions to a close

approximation of its original condition as it existed prior to

disturbance on a former or degraded wetland site. (NRCS)

❑ Bringing back wetland functions to a former wetland area

(Type 1 – Re-establishment)

❑ Improving the condition and functions of a degraded

wetland to reduce, to some extent, the negative impact of

a prior disturbance (Type 2 - Rehabilitation)

What is not wetland restoration?

◼ Creating a wetland where one never existed (wetland creation)❑ Building a marsh-pond by excavating a depression in nonhydric soil down to the water

table (ground water) or adding a clay liner or otherwise compacting substrate to hold surface water.

❑ Making a water garden by excavation and installing a rubber liner

❑ Damming a stream to create a waterbody and fringing wetlands

◼ Changing the type of a wetland to increase one or more functions (wetland enhancement)❑ Converting a wet meadow to a marsh-pond complex for waterfowl

❑ Increasing the hydroperiod of a swamp for waterfowl

❑ Excavating a vernal pool in a swamp for amphibian breeding

❑ Diking and adding fill to a tidal mudflat to create a tidal marsh

Type 1 Restoration – Re-establishment

◼ Area is currently not a wetland but was a wetland in the past❑ Filled Site

❑ Excavated Site (now water)

❑ Effectively Drained Site (drained hydric soil)

❑ Dammed Site (now water)

◼ Restoration involves❑ Restoring wetland hydrology

◼ Removing fill and regrading site to more natural microtopography

◼ Bringing substrate up to a level that would support wetland vegetation

◼ Destroying drainage network (i.e., filling in ditches or breaking tiles) to restore wetland hydrology to the area

◼ Removing dam and restoring streamside wetland

❑ Once wetland hydrology is established, planting desired wetland species (e.g., mast-producing trees on previously farmed bottomlands)

Type 2 Restoration - Rehabilitation

◼ Area is a degraded wetland❑ Hydrologically modified

◼ Wetter than original condition – Dammed/Diked/Impounded or Excavated/Dredged

◼ Drier than original condition - Ditched, or otherwise partly drained

❑ Partially filled ◼ Altered substrate but still wet enough to be wetland

❑ Altered vegetation◼ Forest plantation

◼ Planted with crops

◼ Heavily grazed

◼ Invasive species

❑ Lack of a natural vegetated buffer

◼ Restoration involves❑ Reducing the impact of the disturbance

Steps in Wetland Restoration Planning at the

Watershed Level

1. Identify potential restoration sites

2. Identify likely functions of these sites

3. Identify historic wetland losses in watershed and functions

lost

4. Prioritize wetland restoration for the watershed

Step 1: Identification of Potential

Wetland Restoration Sites Through

Use of GIS and Remote Sensing

How to Identify Potential Wetland Restoration Sites?

Type 1 Sites (Re-establishment):

◼ GIS Analysis and Remote Sensing

◼ Referrals – local knowledge

Type 2 Sites (Rehabilitation):

◼ NWI classifications ❑ Modifiers – d (partly drained), x (excavated), h (diked/impounded), f (farmed),

b (beaver) on areas mapped as hydric soils (to eliminate “created wetlands” from the list)

◼ Remote sensing❑ To update NWI results with more real-time imagery

❑ Look for other features (e.g., fragmentation, more ditching than mapped)

◼ Different water regimes on opposite sites of the road (likely hydrologic alteration)

Source Data: NWI + Hydric Soils + Digital

Imagery + Historic Topographic Maps

◼ Compare NWI vs. Hydric Soils - “Current” Wetlands and Former Wetlands ❑ does not include former wetlands on built-up areas as those areas are not

mapped as a soil type

◼ Hydric Soils – NWI = Hydric Soil Units that are not an NWI wetland or waterbody ❑ Cull out Undeveloped Hydric Soils = “Potential” Wetland Areas

❑ What’s left are Developed Hydric Soils, then identify ones that may be suitable for wetland re-establishment (Type 1 Restoration)◼ Agriculture areas

◼ Disturbed areas with no buildings (e.g., fill)

◼ Waterbodies created on hydric soils

Potential Type 1 site (or Type 2 if not effectively drained) –

former palustrine forested wetland, now cropland or pasture

on hydric soil (Soil code 9 = Scitico, Shaker, and Maybid soils).

Filled Wetlands

USGS Topographic Map 1930s image

Type 1 – Filled Area (former tidal marsh on older

maps and images)

Type 2 Sites

◼ NWI wetlands with

disturbance modifiers (d, f,

h, x, b) occurring on hydric

soil map units

◼ Additional image analysis

❑ Altered hydrology by roads,

railroads

❑ Interpret invasive species

where possible (image – light

brown = Phragmites)

Type 2 SitesExamine latest imagery

Mapped as wetland by NWI but

did not have “d” modifier for

partly drained

Had to examine imagery to

identify ditch network

Yet, we know that for the

Northeast US, most tidal

marshes have been ditched

Emphasizes need to examine

current imagery

Summarize Results in Wetland Restoration Reports

Connecticut – Statewide Assessment:

Reports and Database

◼ Statewide NWI+

Database (4872 sq. mi.)

◼ Four reports

❑ Status

❑ Characterization/Functional

Assessment

❑ Restoration Site Inventory

❑ Trends

◼ Funded by CTDEEP

Geospatial Database: Potential Wetland Restoration Sites

(Note: this NWI+ Mapper no longer supported by USFWS)

Step 2: Identification of Likely

Functions of Potential Wetland

Restoration Sites

Guiding Principles

◼ The location of a wetland in and within an ecoregion and in a watershed, its position on the landscape, its vegetation type, and the surrounding landscape influence the wetland’s ability to perform a variety of functions.

◼ Its condition is largely dependent on disturbances within and outside the wetland and on its landscape setting.

◼ The more two wetlands share characteristics, the more likely they are to be similar in condition and function.

Characteristics Important to Predicting Functions

◼ Wetland Type (Dominant Life-form or Nonvegetated)

◼ Hydrology

◼ Location in the Watershed

◼ Landform

◼ Hydrologic Connectivity (water flow path)

◼ Disturbances

Characteristics Important to Predicting Functions

◼ Vegetation Type - NWI

◼ Hydrology – NWI

◼ Alterations - NWI

◼ Location in the Watershed - HGM

◼ Landform - HGM

◼ Hydrologic Connectivity (water flow path) - HGM

What is the NWI classification missing that is important for

functional assessment?

◼ FEATURES THAT CAN BE SEEN ON A TOPOGRAPHIC MAP

◼ HGM - Abiotic Properties including❑ Landscape Position

◼ Is the wetland along a river, stream, lake, reservoir, or pond?

◼ If not, is it completely surrounded by upland (dryland) or is it the source of a stream?

❑ Landform◼ Is the wetland situated in a depression, on a flat, on a floodplain, or

on a slope?

❑ Water Flow Path ◼ Where is the water coming from and going to from this wetland?

◼ Mostly an issue for Palustrine Wetlands which account for 95% of the wetlands in the lower 48 states

◼ Also missing surficial geology and groundwater relations but that’s beyond what can be done through aerial mapping

Need to Integrate Concept of HGM into Wetland Mapping to

be able to Use Results to Predict Wetland Functions for

Watersheds and Other Large Geographic Areas

◼ Given GIS technology and existing NWI database … add HGM-type descriptors to NWI types to expand classification for:❑ Better characterization of wetlands and waterbodies (especially

Palustrine types)

❑ Increase functionality of the NWI database for use in:

◼ Predicting wetland functions at the landscape level

◼ Identifying potential wetland restoration sites

◼ Apply when updating NWI data

◼ Procedure evolved from working with MA Wetland Restoration Program in the mid-1990s

Enhanced Wetland Database

◼ Takes the basic concept of HGM and applies descriptors for landscape position, landform, water flow path, and waterbody type to NWI data to create an expanded database:

“NWI+ Database”

Note: These data are not a standard product of the NWI; they are a special product that was typically user-funded or user-produced. Several states are doing this or something similar when updating wetland inventory.

HGM-type Descriptors = LLWW Descriptors

◼ Landscape Position – the relationship of a wetland to a

contiguous waterbody

◼ Landform – the physical shape of the wetland

◼ Water Flow Path – the directional flow of water related to the

wetland

◼ Waterbody Type – more descriptive of lakes, ponds,

estuaries, rivers, and streams

Add descriptors to NWI wetlands to create NWI+ Database

Dichotomous Keys for

Classification

(Version 3.0 December 2014)

Detailed and Simplified

Keys plus Illustrated

Examples

Landscape Position

◼ Relationship between a Wetland and a Waterbody

❑ MARINE

❑ ESTUARINE

❑ LOTIC

❑ LENTIC

❑ TERRENE

Marine (associated with ocean)

Estuarine (associated with estuaries)

Lentic (associated with lakes and reservoirs)

Lotic (associated with rivers and streams)

Terrene (geographically isolated, source of stream, or

hydrologically decoupled from stream; latter types often

are groundwater discharge sites)

Landforms

◼ Slope (>2%)

◼ Island

◼ Fringe

◼ Floodplain (basin, flat, island)

◼ Basin

◼ Flat

Water Flow Path

◼ Bidirectional-tidal

◼ Bidirectional-nontidal (lake)

◼ Throughflow

◼ Outflow

◼ Inflow

◼ Vertical Flow (“geographically isolated wetlands” - other

descriptors can show any connectivity between isolated types in “isolated complex”)

◼ Paludified

Landscape Position

and Water Flow Path

Waterbody TypesMore specific types:

◼ Estuary: Drowned River Valley, Bar-built;❑ Macrotidal, Mesotidal (6-12 ft tides), Microtidal

❑ Circulation patterns – salt-wedge, homogenous, partially mixed

◼ Rivers/Streams: gradients, dammed

◼ Lakes: natural, dammed (reservoir)

◼ Ponds: natural (woodland-wetland, woodland-dryland, sinkhole-woodland, sinkhole-prairie, Carolina bay, cypress dome, vernal-woodland, interdunal, floodplain, grady, other), dammed/impounded (aquaculture, agriculture, industrial, golf, stormwater, etc.), excavated (etc.), beaver ❑ Note: can add other types of interest – list is a first cut.

Other Descriptors - Examples

◼ Headwater

◼ Floating mat

◼ Drainage divide

◼ Partly drained

◼ Coastal island

◼ Freshwater wetland discharging directly into an estuary

◼ Overwash

◼ Tidally restricted (road or railroad)

◼ Fragmented

Digital Data Sources Used for Enhanced Classification

◼ Wetlands and waterbodies - NWI

◼ Hydric soils – USDA NRCS SSURGO soils

◼ Topographic data – Digital Raster Graphics (DRG), Digital

Elevation Models (DEM), or LiDAR

◼ Rivers and Streams – National Hydrography Data (NHD)

◼ Digital Imagery – various sources

Predicting Wetland Functions

◼ NWI properties + LLWW descriptors = Geospatial Database

◼ Identify functions of interest

◼ Correlate the attributes in database with wetland functions =

wetland functions assigned to each mapped wetland or

potential wetland restoration site

List of Functions of Interest

◼ Surface Water Detention (inland wetlands)

◼ Coastal Storm Surge Detention

◼ Streamflow Maintenance

◼ Bank and Shoreline Stabilization

◼ Nutrient Transformation

◼ Carbon Sequestration

◼ Sediment and Other Particulate Retention

◼ Provision of Fish and Wildlife Habitat

❑ Fish and Aquatic Invertebrates

❑ Waterfowl and Waterbirds

❑ Other Wildlife

◼ Provision of Habitat for Unique, Uncommon, or Highly Diverse Wetland Plant Communities

Coordinated Effort To Develop Correlations

◼ Reviewed literature

◼ Worked with wetland specialists in the Northeast❑ Maine Wetland Advisory Group

❑ NYCDEP

❑ Nanticoke Wetlands Study Group

❑ FWS biologists

❑ Others

◼ Correlation Report (2003) and Tables (2013)

◼ Should review prior to use in other geographic regions❑ Reviewed/revised for coastal

Georgia, Wisconsin, and New Mexico

◼ User Adaptable (can modify functions of interest)

Step 3: Identification of Lost

Functions for the Watershed

Historic Assessment

◼ Hydric Soils data = “historic wetlands” (best approximation) ❑ GIS and Image Analysis – locate lost wetlands (converted hydric soils)

◼ Easier to do in agricultural or forest regions vs. urban/suburban locales

❑ Wetland type classification – based on soil type and characteristic vegetation at remaining wetlands on this hydric soil

◼ Historic Wetlands – Existing Wetlands = Lost Wetlands

◼ Functions of Lost Wetlands❑ Apply NWI type and LLWW descriptors then use correlation table to

determine likely functions

❑ Combine with assessment of current wetland functions, if of interest

❑ Determine wetland losses as they relate to wetland functions (lost functions)

Assessing the Impact

of Wetland Changes:

Historic Changes for

Nanticoke Watershed

Nanticoke Wetland Stats

Pre-settlement

◼ 230,000 acres

◼ 2,814 wetlands

◼ 72% outflow wetlands❑ Average size = 433 acres

1998

◼ 142,000 acres (62% of pre-settlement acreage)

◼ 5,810 wetlands

◼ 43% decrease in outflow wetlands❑ Average size = 44 acres

◼ Palustrine wetlands – lost 40%

◼ Estuarine wetlands – lost 28%

Impact of Wetland Changes on Functions

(Pre-settlement to 1998)

◼ Surface Water Detention = -36%

◼ Streamflow Maintenance = -64%

◼ Nutrient Transformation = -47%

◼ Sediment Retention = -46%

◼ Coastal Storm Surge Detention = -23%

◼ Fish-Shellfish Habitat = -33%

◼ Waterfowl-Waterbird Habitat = -34%

◼ Other Wildlife Habitat = -41%

Result = Preliminary

◼ Analysis can produce:

❑ A historic perspective on the significance of losses at the watershed

level

❑ Predicted functions for potential wetland restoration sites

◼ Need to examine most current imagery and field check

determinations for “potential restoration sites” prior to actual

planning restoration for specific locations

NWI+ Data and Reports By FWS Posted Online

◼ USFWS Region 5

❑ https://www.fws.gov/northeast/ecologicalservices/wetlandspubs.html

❑ Look under Inventories of potential wetland restoration sites and

Watershed-based wetland studies

◼ USFWS NWI Documents Search Engine

❑ https://www.fws.gov/wetlands/Search.html#gsc.tab=0

❑ Type in “Tiner Wetland Restoration Watershed”

◼ ASWM’s Wetlands One-Stop

Mapping

❑ http://aswm.org/wetland-

science/wetlands-one-stop-

mapping

❑ Look under NWI+ Mapper for

display of results and NWI+

Reports for copies of summary

reports

◼ New Book: Academic Press

Step 4: Prioritization of Restoration

Sites

Problems That May Benefit from Wetland Restoration

◼ Developed areas subject to flood damages

◼ Watercourses and waterbodies experiencing degraded

water quality

◼ Fragmentation of wetlands and other natural habitats

Regulatory Agencies and Watershed Associations should

know where these areas are located

Where to Begin

◼ Lost functions – historic analysis

◼ Identify problems that can be reduced by wetland restoration

❑ Flood-prone areas

❑ Polluted waters

❑ Wetlands with buffers in poor condition

◼ Locate potential restoration sites relative to known problem

areas

◼ Rehabilitate disturbed wetlands

Agency/Organization Determines Priorities

◼ After identifying problem areas, use the wetland restoration site

database to locate sites that may help reduce a problem, such as

❑ More flood storage wetlands above flood-prone development

❑ Restore wetlands below the pollution source to help renovate poor

water quality

❑ Improve water flow between contiguous wetlands

❑ Lessen habitat fragmentation on the landscape - use wetlands to

improve habitat connectivity between conservation lands

❑ Control invasive species

❑ Restore vegetative buffers along watercourses and waterbodies.

❑ Consider historic losses to set priorities

Now let’s look at how these techniques

have been used to produce information

vital for conserving wetlands at the local

level

Lake County, Illinois