The Upper Midwest is
experiencing an extended period of drought but don’t tell that to
the thousands of people who have been significantly affected by
flooding in the last several years. It seems the drought is more
related to elevation than to general location. If you live in an
area that is less than 1000’ above sea level you may be experiencing
a lot of moisture and a higher water table. If you live in an area
that approaches 2000’ above sea level (read North Central WI and
other elevated State locations) you are probably experiencing a
quite different situation. In addition to declining lake and river
levels in North Central WI, a profoundly diminished overall water
table looms large for current and future water users in the area.
This is the crux of the problem.
If we could lay the blame on
the weather forecasters for the lack of rain or snow, assuming
somehow they would accept responsibility, we could quietly go about
grumbling and complaining and, of course, nothing would be
accomplished. But, as is often the case, the real issues here are
global climate change and a blind eye to indiscriminate resource
use.
A recent presentation by
noted key speakers took place at the Northland Pines High School in
Eagle River, WI and looked at these issues in depth. Buzz Sorge,
Lake Management Planner for the DNR West Central Region, Susan
Knight, UW Aquatic Biologist for the Trout Lake Limnology DNR Office
and Tim Asplund, Statewide Limnologist for the WDNR Lakes and
Wetland Section all made presentations on the issues of:
1)
What sort of changes declining lake levels
trigger including habitat change and
2)
The implications of climate change with
respect to declining inland lake levels
One of the most compelling issues of reviewing statistical data
recapping time periods from 30 to 70 years ago which look at North
Central WI precipitation levels, wet and dry periods and even the
water table of the Eagle River community well (which is at an
all-time low), is the fact that although the spikes of the pictorial
graphs show nearly equal returns from dry and wet sequences of time,
the land’s overall water retention has declined. If you accept the
explanation that annual rainfall and snowfall is pretty much
balanced out by the process of moisture transfer from water bodies
to the air through evaporation then the only other possibility for
lake level decline is the ever declining water table, underground
water level, the aquifer, whatever terminology you’re comfortable
with. So why is this occurring? In the past when we did return to a
wetter cycle the water table increased but it never returned to its
original place. Over all water levels continue to decline and warmer
winters, sooner ice out, later ice in and warmer summer weather
(despite local differences currently being experienced) continues to
tax the water replacement cycle. The human impact of increased
population in North Central WI leading to more private wells tapping
into the various aquifers also factors into the equation. How could
it not?
The implications of declining lake levels is first and most apparent
in more exposed shorelines. Critical here is the natural response
to clean out formerly submerged wood to make the shoreline more
attractive
Words to the wise.
Leave it. Wood removal has been established as the leading cause of
fish habitat decline since it supports so much invertebrate life for
forage and reproduction cycles. Second is the obvious loss of water
habitat for fish movement and the associated problems with a
diminished overall habitat. Finally, and just as important to water
recreationists, there is the loss of access and mobility for
watercraft. Low water levels can cause or increase the likelihood
of:
·
Algal blooms especially if the water body
is already experiencing over fertilization
·
Invasive species dominance
·
Greater winter fish kills due to depleted
dissolved oxygen in the water
·
Loss of water clarity
·
Loss of recreational use
Given the fact that less than 1% of all water on earth is of the
fresh water category and only .009% is contained in inland lakes,
what this State has in terms of precious, perhaps not overstating
the case, rare resources need to be looked at in a new light. 90%
of the life found in a fresh water body lives or is dependent on the
littoral zone, that portion of the water body that supports aquatic
plant production and is generally accepted to be a depth less than
30’ or that depth to which sunlight can easily penetrate. It is also
the area where most of the zooplankton is found, a major dietary
requirement for small fry. Overall declining water levels have the
greatest impact on fish reproduction. So the importance of leaving
branchy fallen wood on your shoreline is important as research has
shown a threefold increase in fish population and growth in woody
habitat with the corollary of wood removal immediately effecting
perch population declines and a change in bass forage to terrestrial
nutrition. Recent studies have also overwhelmingly concluded that
developed shorelines and lawns especially discharge 7-10 times more
phosphorus runoff to water bodies than adjacent woodlands.
Over all moisture levels for the long-term show a 50-year decline,
perhaps a 15%-20% drop in elevated areas of the State. How we as
landowners and shoreline users have impact is by recognizing the
effect we and other users inflict. Of particular concern for
shallow water areas are the boat wave characteristics that we cause
under heavy acceleration to get the hull up on plane. High speed
near shore takeoffs are the most egregious forms of shoreline
mistreatment as a result of bottom disruption and natural aquatic
plant damage. Stronger no-wake zone regulations need to be enacted,
observed and enforced.
It’s all not so unlikely.
We have been in the process of “lovin' this area to death” for over
a half century and don’t forget it was heavily logged a little over
a century ago, the habitat effects of which went essentially
undocumented. It would be difficult to believe that extensive
logging operations did not inevitably trigger some significant
microclimate and ecosystem changes. As population relocation
increases the number of residents in North Central WI the situation
isn’t going to self-correct. It’s here. The key is to focus on the
unique water resource and to become committed to protecting it.
In conclusion it would seem
that there are two schools of thought on the environmental issues.
There are resources-land, water and air that provide us with
tangible and intangible benefits but it is when we treat these
resources like commodities it becomes difficult to refocus on the
common sense limitations of the resource itself. True commodities
are bought, sold and traded but resources aren’t found in stock
market listings and try as we might to extract every last drop of
resource available, and many are trying, we don’t have the ability
to crank up the assembly line, here or in China, and make some
more.
Reported by Jeff Burke at
the 2009 annual meeting