Definitions, abbreviations & explanations of Lake Information
Introductory information - pdf form
Lake Variability and Descriptions
Each lake has qualities which make it unique, much like people with distinct
personalities. Lakes vary based on physical characteristics, such as size, depth,
configuration, chemical characteristics (such as soft versus hard water), water
clarity, or the types of plant and animal life present. For example, hard water lakes
have higher levels of dissolved minerals such as calcium, iron and magnesium than
soft water lakes. Some lakes, especially those near acidic wetlands like bogs, are
stained with tannic acid that leaches from surrounding vegetation. The water in
these "tannin lakes" may range in color from a dark brown "coffee" color to light
Natural lakes in Wisconsin frequently are classified by the source of water supply.
Based on water source and outflows, four categories of lakes have been identified
in this publication:
1. Drainage lakes - These lakes have both an inlet and outlet where the main water
source is stream drainage. Most major rivers in Wisconsin have drainage lakes
along their course. Drainage lakes owing one-half of their maximum depth to a dam
are considered to be artificial lakes or impoundments.
2. Seepage lakes - These lakes do not have an inlet or an outlet, and only
occasionally overflow. As landlocked waterbodies, the principal source of water is
precipitation or runoff, supplemented by groundwater from the immediate drainage
area. Since seepage lakes commonly reflect groundwater levels and rainfall
patterns, water levels may fluctuate seasonally. Seepage lakes are the most common
lake type in Wisconsin.
3. Spring lakes - These lakes have no inlet, but do have an outlet. The primary
source of water for spring lakes is groundwater flowing into the bottom of the lake
from inside and outside the immediate surface drainage area. Spring lakes are the
headwaters of many streams and are a fairly common type of lake in northern
4. Drained lakes - These lakes have no inlet, but like spring lakes, have a
continuously flowing outlet. Drained lakes are not groundwater-fed. Their primary
source of water is from precipitation and direct drainage from the surrounding land.
Frequently, the water levels in drained lakes will fluctuate depending on the supply
of water. Under severe conditions, the outlets from drained lakes may become
intermittent. Drained lakes are the least common lake type found in Wisconsin.
Artificial lakes are human-made bodies of water referred to as impoundments. In
this publication, a lake is considered an impoundment if one-half or more of its
maximum depth results from a dam or other type of control structure. An impoundment
is considered a drainage lake since it has an inlet and outlet with its principal
water source coming from stream drainage. Approximately 13 percent of Wisconsinís
lakes fit this definition.
Lake Type Characterizations
The water quality of a lake and species of fish present are significantly influenced
by the lake type. For example, drainage lakes support fish populations which are not
necessarily identical to the streams connected to them. Drainage lakes, particularly
impoundments, usually have higher nutrient levels than many natural seepage or
In contrast to drainage lakes, landlocked seepage lakes are not influenced by
streams. Consequently, seepage lakes frequently have a less diverse fishery.
Seepage lakes also have a smaller drainage area, which may help to account for
lower nutrient levels.
About the Contents of this Publication
This booklet contains information on all named lakes in Wisconsin and all unnamed
lakes of more than 20 acres. The lakes are listed alphabetically by county. The
following notes may help you use this publication.
Lake Name - The official name is listed according to "Wisconsin Geographical
Names" and as shown on U.S. Geological Survey 71/2 minute quadrangle maps.
Many lakes also have a different local name, which is listed in parenthesis after the
official name. An asterisk (*) following the lake name indicates that the lake is a
border lake and is counted for total number of lakes and acreage in another county.
Surface Area - This column provides information on the lake size of a lake in acres
of open water. For lakes that span state lines total acreage is given in the column
under surface area and the Wisconsin acreage is listed in parenthesis after the lake
name. The area below the ordinary high water mark (OHWM), which is legally the
lake's bed, may be a different size.
Maximum Depth - The maximum depth in feet is recorded at the deepest point in
a lake. All lakes in this publication should have a maximum depth listed.
Mean Depth - The mean depth in feet is an average determined from the lake
volume and area. Not all lakes have a mean depth listed, only those with completed
lake survey maps.
Public Access - Detailed access information is available for most counties in the
state. Many public fishing piers are now wheelchair-accessible. For information on
specific access sites, contact your nearest DNR office. Each office has a copy of
Fishing and Boating Access for Everyone. Copies of individual location maps with
descriptions of the amenities available at that site can be provided to you. In the
column titled "Public Access," the following abbreviations describe existing access
where information is available:
BRBoat Ramp. These are sites with a defined public boat launching facility
which may or may not have parking.
BFBarrier-free Boat Ramp. These sites have a boarding dock or means of
wheelchair access to boats.
PBarrier-free Pier. These piers were designed to accommodate wheelchairs.
TWalk in Trail. These access sites are partially developed, excluding a boat
ramp, and are entirely within public lands.
RRoadside. These sites do not include any access developments. Public roads
with a marked right-of-way extending to the water provide a limited degree
WWilderness in Public Ownership. A lake is in a wilderness area if there are no
roads or buildings within 200 feet of the waterbody. Wilderness lakes have
no defined walk-in trail to the water.
BWBarrier-free Wilderness Access. These site have a firm surface to gain access
to the water, but no special piers or ramps.
NWNavigable Water. Navigable access is provided by the presence of an inlet or
outlet stream which furnishes adequate boat access to a lake. A small stream
not large enough to float a boat does not provide effective navigable access.
A few counties do not have detailed access information. For those waters marked
with an "x," some type of access, other than navigable water access, is available.
Regulations governing boat usage are effective on certain lakes and are posted at
the public access sites.
Map - If a lake survey map showing the contour depths in a lake is available, an "X"
appears in the column called "Map." Nearly one fourth of all the named lakes in the
state have been mapped. Lake survey maps provide valuable information for lake
property owners and anglers who wish to know more about the lake depths.
Lake Type - The four lake types identified in this publication are defined on page
one. The following abbreviations describe the category of lake type:
DG= Drainage lake SE = Seepage lake
SP= Spring lake DN = Drained lake
Species of fish - The relative abundance of various game fish species including
muskellunge, northern pike, walleye, largemouth bass, smallmouth bass, panfish,
trout, catfish and sturgeon is listed. Abundance of a fish species is coded using the
A= Abundant C = Common P = Present
The absence of any symbol means that a fish species is not present.
Some recent exotic species -
E= Eurasian Water Milfoil (Myriophyllum spicatum)
It is an aquatic plant.
Z= Zebra Mussel (Dreissena polymorphia).