ASSESSING THE QUALITY AND ASSESSING THE QUALITY AND QUANTITY OF DEPRESSIONAL QUANTITY OF DEPRESSIONAL

WETLANDS IN THE REDWOOD RIVER WETLANDS IN THE REDWOOD RIVER WATERSHED UTILIZING A WATERSHED UTILIZING A

PROBABILISTIC SURVEY DESIGNPROBABILISTIC SURVEY DESIGN

John GenetJohn GenetMN Pollution Control AgencyMN Pollution Control Agency--St. Paul, MNSt. Paul, MN

Anthony R. OlsenAnthony R. OlsenUS EPA NHEERLUS EPA NHEERL--Corvallis, ORCorvallis, OR

EMAP 2007 SymposiumEMAP 2007 SymposiumApril 10April 10--1111thth 20072007Washington, DCWashington, DC

Index of Biological Integrity (IBI)

– Multimetric Index– Based on deviation

from reference conditions (least impacted sites)

– Measurement of condition (quality)

Introduction

DisturbanceIB

I

Assessment– Aquatic Life

Use Support (ALUS)

– Impairment threshold

• Lowest scoring reference site

– Confidence interval

Introduction

HDS

IBI

90% C

I

ImpairmentThreshold

= reference

= impacted

Study Objectives

• Assess quality of depressional wetlands in a watershed using a probabilistic survey

• Estimate wetland loss since early 1980s• Evaluate feasibility of utilizing a

randomized survey design for wetland condition monitoring

Study Area-Redwood River

Locator map

GrasslandGrassland7.4%7.4%

AgricultureAgriculture85.6%85.6%

UrbanUrban 1.1%1.1%Rural DevelopmentsRural Developments

1.4%1.4%

WetlandsWetlands0.5%0.5%

Open WaterOpen Water1.5%1.5%

ForestForest2.6%2.6%

Gravel pits, Mines, Gravel pits, Mines, & Exposed Soil 0.1%& Exposed Soil 0.1%

Target Population

Seasonal, Semi-permanent, & Permanent Emergent Depressional Wetlands

Sample Frame-NWI

Invert IBI calculated & ALUS assessment conducted25 sites (1808 est. ha)

Plants and Sediment Sampled

40 sites (2721 est. ha)

Inverts and Water Chemistry Sampled39 sites (2721 est. ha)

EMAP draw350 Sites

Site Evaluation146 sites evaluated to obtain 40 target sites

Target40 sites (2721 est. ha)

Plant IBI calculated & ALUS assessment conducted40 sites (2721 est. ha)

Site Selection & Sampling

106 sites were either absent,non-target, not sampleable,or not accessible

Results-Water Chemistry

Total Kjeldahl Nitrogen (mg/L)

0 1 2 3 4 5 6 7%

of w

ater

shed

0

20

40

60

80

100

Dep

ress

iona

l Wet

land

Are

a (h

a)

0

500

1000

1500

2000

2500

CDF estimate95% Confidence Limits

Chloride (mg/L)

0 10 20 30 40 50 60

% o

f wat

ersh

ed

0

20

40

60

80

100

Dep

ress

iona

l Wet

land

Are

a (h

a)

0

500

1000

1500

2000

2500

CDF estimate95% Confidence Limits

Chloride Total N

Regional Reference Conditions

Results-Invertebrate IBI

Macroinvertebrate IBI

0 10 20 30 40 50 60 70 80

% o

f wat

ersh

ed

0

20

40

60

80

100

No.

Sem

i-per

man

ent &

Per

man

ent W

etla

nd B

asin

s 0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

CDF estimate95% Confidence Limits

Macroinvertebrate IBI

0 10 20 30 40 50 60 70 80

% o

f wat

ersh

ed

0

20

40

60

80

100

Sem

i-per

man

ent/P

erm

anen

t Dep

ress

iona

l Wet

land

Are

a (h

a)

0

200

400

600

800

1000

1200

1400

1600

1800

CDF estimate95% Confidence Limits

Number of Basins Cumulative Area

ImpairmentImpairmentBasins Basins –– 86%86% Area Area –– 97%97%

Biological Impairment Threshold

Results-Plant IBI

Plant IBI

0 20 40 60 80 100

% o

f wat

ersh

ed

0

20

40

60

80

100

No.

of E

mer

gent

Dep

ress

iona

l Wet

land

Bas

ins

(Sea

sona

l, Se

mi-p

erm

anen

t, &

Per

man

ent)

0

100

200

300

400

500

600

700

800

CDF estimate95% Confidence Limits

Plant IBI

0 20 40 60 80 100

% o

f wat

ersh

ed

0

20

40

60

80

100

Dep

ress

iona

l Wet

land

Are

a (h

a)

0

500

1000

1500

2000

2500

CDF estimate95% Confidence Limits

Number of Basins Cumulative Area

Biological Impairment Threshold

ImpairmentImpairmentBasins Basins –– 63%63% Area Area –– 81%81%

Results-ALUS

Use Support Assessment

support non-support

% o

f wet

land

bas

ins

0

20

40

60

80

100

# D

epre

ssio

nal W

etla

nd B

asin

s

0

100

200

300

400

500

600

700

800

Use Support Assessment

support non-support

% o

f wet

land

are

a0

20

40

60

80

100

Dep

ress

iona

l Wet

land

Are

a (h

a)

0

500

1000

1500

2000

2500

Error bars = 95% Confidence limitsError bars = 95% Confidence limits

Results-ALUS

Results-Site Evaluation

Sampled, 40Riparian Wetland, 20

Lake, 2

Not Sampleable, 17

Landowner Denied, 5

Absent, 62Not Sampled, 106

All All Evaluated SitesSites Dropped SitesDropped Sites

Results-Basin Extrapolation

00

200200

400400

600600

800800

10001000

12001200

< 1 ha< 1 ha 11--5 ha5 ha 55--10 ha10 ha > 10 ha> 10 ha TotalTotal

# W

etla

nd B

asin

s#

Wet

land

Bas

ins

Depressional Wetland:AbsentDepressional Wetland:AbsentDepressional Wetland:PresentDepressional Wetland:PresentLakeLakeRiparian WetlandRiparian Wetland

Results-Area Extrapolation

00

500500

10001000

15001500

20002000

25002500

30003000

< 1 ha< 1 ha 11--5 ha5 ha 55--10 ha10 ha > 10 ha> 10 ha TotalTotal

Wet

land

Are

a (h

ecta

res)

Wet

land

Are

a (h

ecta

res)

Depressional Wetland:AbsentDepressional Wetland:AbsentDepressional Wetland:PresentDepressional Wetland:PresentLakeLakeRiparian WetlandRiparian Wetland

Results-Wetland Losses

Size Estimated No. of Wetland Basins Estimated Wetland Area (ha)Category (ha) circa 1980 2003 % change circa 1980 2003 % change

< 1 1475 536 -63.6 486.8 201.7 -58.61-5 407 241 -40.9 848.2 541.2 -36.25-10 58 39 -33.3 396.2 266.8 -32.7> 10 51 48 -6.2 1741.7 1711.1 -1.8

Total 2012 896 -55.5 3437.6 2714.4 -21.0

• Majority of depressional wetlands in the Redwood are biologically impaired

• Likely stressors: nutrients, invasive species, sedimentation, altered hydrology

• Significant losses of small (seasonal) wetland basins from 1980-2003

• These are not net losses– No accounting for permitted actions & mitigation,

and/or wetland additions from conservation programs (CREP, WRP, etc)

Conclusions

• Accurate sample frame is crucial– NWI format is

problematic– Data is > 20 yrs

• Access not a big issue

Conclusions-Probabilistic Survey

PEMCd

PEMFd

PEMFd

PEMAd

PEMFd

PEMFd

NWI Wetland Classification:wetland type polygons

MPCA Assessment Unit:

wetland basin

Mark Gernes – idea for project, study design, field work, comments & suggestions on reportMichael Bourdaghs - comments & suggestions on report, assistance with presentation

Field Crew EPA SupportJoel Chirhart Rich SumnerHarold Wiegner Mary KentulaMaureen Minister Naomi DetenbeckBruce Sandstrom Sue ElstonAdam Hoffman Alicia HernandezTravis Fristed

Acknowledgements

Comprehensive Wetland Assessment, Comprehensive Wetland Assessment, Monitoring, and Mapping Strategy Monitoring, and Mapping Strategy (CWAMMS)(CWAMMS)

• Probabilistic Survey of Wetland Quantity and Quality (Statewide Status & Trends)

• Update NWI • Develop Web-Based

Wetland Accounting System (permit and mitigation tracking)

AA CCoommpprreehheennssiivvee WWeettllaanndd AAsssseessssmmeenntt,,

MMoonniittoorriinngg,, aanndd MMaappppiinngg SSttrraatteeggyy

ffoorr MMiinnnneessoottaa

July 2006July 2006

Probabilistic Statewide Wetland SurveyProbabilistic Statewide Wetland Survey33--Panel Interpenetrating DesignPanel Interpenetrating Design

Year (Panel) 1 Year (Panel) 1

1580 1 mi1580 1 mi22 plotsplots

Year (Panel) 2 Year (Panel) 2

1580 1 mi1580 1 mi22 plotsplots

Year (Panel) 3 Year (Panel) 3

1580 1 mi1580 1 mi22 plotsplots

+ 250 Common Plots Sampled each year + 250 Common Plots Sampled each year ---------------------------------------------------------------------->>

Panel 1: 2006 Wetland Quantity StatusPanel 1: 2006 Wetland Quantity Status2007 Wetland Quality Status2007 Wetland Quality Status

20062006Panel 1 (black) and Panel 1 (black) and Common plots (red)Common plots (red)

http://www.pca.state.mn.us/water/biomonitoring/bio-wetlands.htmlRedwood Report available at:

Questions?

More CWAMMS information available at:http://www.pca.state.mn.us/water/wetlands/cwamms.html