Adapting to Low Lake Levels and the
Implications of a Changing Climate
Many factors affect water levels
Lake morphology and hydrology
z Landscape position
z Natural variability (weather)
z Short term drought (and wet) cycles
z Climate change
z Human water use (i.e. water withdrawals)
z
Bass Patterson Lake, Washburn County (E. Cook)
Changes in the Hydrologic Cycle
Krohelski 2003
Statewide trends and contrasts
2828-day streamflow compared
to long term average (April)
Precip departures from
normal
How does this compare longterm?
Seasonal differences
Summer (JJA)
Long term perspective
Winter (DJF)
Response of Lakes to Drought
Fig 3.2
Magnuson et al. 2006
LTER Lake Levels, Vilas Co
495.5
Big Muskellunge Lake, Vilas County
2005
2003
2001
1999
1997
1995
1993
1991
1989
1987
1981
2005
2003
2001
1999
1997
1995
1993
1991
1989
1987
494
1985
500.5
1983
494.5
1985
495
501
1983
MSL (m)
502
501.5
Trout Lake, Vilas County
501.5
492.5
492
2005
2003
2001
1999
1997
1995
1993
1991
1989
1987
2005
2003
2001
1999
1997
1995
1993
1991
1989
1987
1985
1983
491
490.5
1981
500
499.5
1985
491.5
1983
500.5
1981
MSL (m)
501
MSL (m)
Eagle River well record
Sparkling Lake, Vilas County
496
1981
MSL (m)
Crystal Lake, Vilas County
502.5
Tomahawk Lake, Bayfield County
Source: NTL LTER, Center for Limnology
Anvil Lake Stage Record
(1936 – 2006)
Anvil Lake – Regime shift?
Anvil Lake, Vilas County, WI
8
7
7
6
6
Stage height (ft)
Stage, in feet
Hydrograph for Anvil Lake, Vilas Co
8
5
4
3
5
4
3
2
2
1
1
0
100%
0
1/1/30
1/1/40
1/1/50
1/1/60
1/1/70
1/1/80
1/1/90
1/1/00
Source: USGS
1/1/10
1985-2007
1936-1981
80%
60%
40%
20%
% of time lower than stage height
0%
Source: USGS
Climate Change in the Great Lakes Region: Starting a Public Discussion
Global Warming Is Unequivocal:
• The recent IPCC report has clearly stated that
“warming of the climate system is unequivocal” and it is
“very likely” caused by human activities.
• Moreover, most of the observed changes are now
simulated by models over the past 50 years, adding
confidence to future projections.
Source: OSTP
Evidence of Climate Change
in the Great Lakes Region
Temperatures are rising, especially in
winter.
z Extreme rainfall events (24(24-hr and 77-day)
are becoming more frequent.
z Winters have become shorter.
z Spring is coming earlier.
z Duration of ice cover is shorter,
especially on smaller lakes.
z
Long term precipitation trends
Source; Edge of the Wilderness Scenic Byways
SOURCE: UCS/ESA, 2003
Climate change in Wisconsin: 1950-2006
Kucharik et al., in prep
in c
re
as
e
15-20% decrease
15
%
10-15% increase
50-150 mm/year increase
(0.2 to 0.6 inches/year)
~20% increase
~15% increase
Which one is the future?
Effects of Global Warming on Water Cycle
Global Warming
(temperature increase)
Speeds up Global
Water Cycle
More Extreme Weather Events
Effects on
lakes?
• Droughts
• Storms
• Floods
Maybe both!
Devil’
Devil’s Lake Stage Record
(1935(1935-2006)
Water Levels – Scenario #1
z
z
z
z
z
Warmer, wetter
winters
More CO2 in
atmosphere makes
plants more water
efficient
More storms
increases runoff
More recharge
increases baseflow
and groundwater
levels
Lakes may go up
1935
1970
2005
Source: USGS
Source: John Magnuson, 2007
Shell Lake Stage Record
(1936 – 2006)
Water Levels – Scenario #2
z
1226
1224
z
1222
1220
1218
1216
z
1214
1/1/30 1/1/40 1/1/50 1/1/60 1/1/70 1/1/80 1/1/90 1/1/00 1/1/10
z
Source: USGS
Shorter duration of ice
cover will increase
evaporation in winter
Warmer air
temperatures will
increase
evapotranspiration
Lower precipitation in
summer will decrease
soil moisture
Lakes may go down
SOURCE: UCS/ESA 2003
Step Increase in Lake Stage, Stream Flow,
and Groundwater Levels after 1970
Groundwater Well
Lake Stage
Stream Flow
(!
!
(!
(!
Shell Lake
!
Eagle River Well
Anvil Lake
!
(!
(!
(!
(!
(!
(! (!
(! (!
(!
Gray = step increase
Red = no step increase
(!
(!
(!
(!
Devils Lake
Source:
WGNHS
USGS Data
Magnuson et al. 2003
Role/implications of climate change
for lake levels in the north
Short term or long term?
z Factors at play
z
z Changing
timing of precipitation
in snowfall and recharge
z Increased summer evaporation
z Decreased summer rainfall
z High in the landscape regionally
z Groundwater Divides
z Changes
OK, SO NOW WHAT?
Wait it out!
z Natural variations are part of
lake ecosystem
z But, larger forces at work
(climate change, water use,
land use)
z Solutions may be local,
regional, and global
z Mitigation vs Adaptation
z
Adapting to low lake levels
z
Understand your lake
z Careful use of lakes and lakeshores
z Protect habitat – fragile ecosystems
z Reduce nutrient inputs
z Shift boating behavior – go deep!
z
Boat wave characteristics
(adapted from Maynord,
Maynord, 2005)
Low water can lead to navigational issues and disturbance to lake beds
Boat speed and water depth
affect sediment disturbance
Maximum wave height
Planing
Wave Height
Displacement
Semi-planing
Maximum Bed Velocity (cm/sec)
70
60
50
40
30
20
10
0
Speed or applied power
Observed (188 cm)
Observed (157 cm)
Observed (127 cm)
Predicted (188 cm)
Predicted (157 cm)
Predicted (127 cm)
0
10
20
30
Boat Speed (mph)
(From Beachler and Hill, 2003)
Sediment
disturbance
Sediment
disturbance
Sediment
disturbance
Weekday to Weekend Change (Asplund, 1996)
Near-shore
Mid-lake
0.00
Boat Density
-0.10
30
Secchi (m)
# boats per 100 ha
40
20
10
-0.20
-0.30
-0.40
-0.60
Shallow lakes
Deep lakes
Shallow lakes
20.0
0.80
Total P
Turbidity
12.0
8.0
0.40
0.20
4.0
0.0
0.00
Shallow lakes
Deep lakes
Shallow lakes
Deep Lakes
Plant Growth – Lake Ripley
Chara Beds with
Propeller Tracks
Solid
160
120
80
40
0
South
North
South
Plot
Buoys
moved
toward
shore
Buoys in
place
Long Lake
Pre-study
Control
Mesh
2
Plant Total Biomass (g/m )
200
North
Fond du
Lac Co.
Deep Lakes
0.60
NTU
µg l -1
16.0
No-wake
zones
protect
plants from
disturbance
Water clarity
-0.50
0
East
North
West
South
Adaptation strategies during
times of low water
Does your lake experience natural water level fluctuations? Such lakes:
may have these problems
aquatic invasive plant species that are adaptable to water level increases or decreases
damage to unique habitats by human use during low water periods
sensitivity to changes in groundwater recharge
a large area less than 8 feet deep during some parts of the year
winter fish kills
removal of woody material, leading to loss of potential habitat for fish during periods of high water and may benefit from
looking for and removing exotic aquatic invasive plants during low water periods
establishing barriers to prevent vehicle access to the dry lake bed during low water periods
use of swales and rain gardens to encourage infiltration of rainwater and snowmelt
no‐wake speeds or electric‐motor‐only zoning
adding oxygen when necessary by mechanical aeration or by plowing snow off the lake surface to encourage plant growth
leaving fallen trees, logs, or branches in place or adding them to the exposed lake bed during low water periods Mechenich and Turyk
UWSP