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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)
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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