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MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
The ability of streams to withstand the
effects of urbanization Tom Danielson, PhD
Leon Tsomides Doug Suitor
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION
Protecting Maine’s Air, Land and Water
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Overview
• Lessons learned from Impervious Cover study
• Factors that make streams more resilient or vulnerable to urbanization
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Impervious Surfaces
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Stream Watersheds
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Spatial Resolution Matters
• We computed % IC with 3 spatial layers. – 30m resolution
• 2001 National Land Cover Data (NLCD) – 5m resolution
• 2004 Maine Land Cover Data (MELCD) – 1m resolution
• 2004 MELCD and MEIFW
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Advancements in IC Estimates
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Advancements in IC Estimates
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
2001 NLCD – 30m resolution
30m
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
2004 MELCD – 5m resolution
5m
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
2004 MELCD – 1m resolution
1m
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Spatial Resolution Matters
• 5 m spatial compared to 1 m spatial data – overestimates % IC in urban and suburban
areas – underestimates % IC in rural areas
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Impervious Cover Thresholds
Previous studies have found threshold effects on stream biota ranging from 1-15% IC.
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Stream Classes
% OF LINEAR MILES OF STATUTORY CLASSIFICATIONS
Class AA = 6%
Class A = 45%
Class B = 47%
Class C = 2%
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Biomonitoring Results %
Impe
rvio
us C
over
0
10
20
30
40
50
AA/A B C NA
A
Macroinvertebrate Result
0
10
20
30
40
50
AA/A B C NA
B
Algae Result
~25% of data
~25% of data
~25% of data
~25% of data
median
Tom Danielson, Maine DEP
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Risk of Not Attaining Biological Criteria
% Impervious Cover
0 5 10 15 20
High Risk
High Risk
High Risk
Low Risk
Low Risk
Class AA/A
Class B
Class C
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
IC Targets
• “How much IC is too much for this watershed?”
• “What is a good restoration target for this watershed?”
• Answer: “Well, it depends.”
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Factors that Influence Resilience of Streams to
Urbanization
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
1. Condition of Riparian Zone
Kennedy Brook, Augusta
Penjajawoc Stream, Bangor
Whitten Brook, Skowhegan
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Riparian Zones • Sites with more IC in
50 m buffer zone had less Mayfly, Stonefly, and Caddisfly (EPT) Taxa
• The size of points indicates the amount of IC in a 50m buffer zone
0 10 20 30 40 50
0.1
0.2
0.3
0.4
0.5
0.6
0.7
% IC
EP
T re
lativ
e ric
hnes
sEP
T Ta
xa R
elat
ive
Ric
hn
ess
Watershed % IC
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
2. Condition of Headwaters
Perkins Brook, Waterville
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
3. Stream Channel Alteration
Unnamed Stream, Waterville Lindsay Brook, Rockland
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
4. Habitat Fragmentation
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
5. Road Crossings and Culverts
Concord Gully, Freeport, Source: MPBN Tributary to Bond Brook, Augusta
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
6. Water Source
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
7. Watershed Connection
Fall Brook, Portland
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
8. Agriculture
Fence Protects Stream Cows in Stream
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
source: NRCS
source: NWF
Buffer Strips and Contour Tilling
Erosion from Traditional Tilling
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
9. Groundwater Quality
Fish Brook, Fairfield
Upstream Control Downstream Impact
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
10. Nutrient Enrichment
Capisic Brook, Portland
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
11. Salt Application
Source: Road Salt Institute
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Salt Pile
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Salt Pile
2,750 µS/cm
1,600 µS/cm
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
12. Polluted Runoff
Birch Stream, Bangor
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
Take Home Messages • There are different ways to measure IC • There is more to urbanization than IC • A variety of factors make streams more or
less resilient to urbanization • Urbanization can impact aquatic life at
very low levels
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION www.maine.gov/dep
www.maine.gov/dep thomas.j.danielson@maine.gov
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