What is the Ordinary
High Water Level?
The Ordinary High
Water Level (OHW), is the highest level at which the water has remained
long enough to leave evidence on the landscape. Generally, it is the
point where the natural vegetation changes from predominantly aquatic
to predominantly terrestrial plants. In streams, the OHW mark is generally
the top of the bank of the channel.
Why do the water levels
in lakes change?
Lake levels fluctuate
naturally due to rain, snowmelt, drought, or changes in groundwater
level. Any land use changes within a particular watershed may cause
a change in the level of a lake within the watershed. Irrigation,
drainage, sediment deposits, dams (built by beavers or humans), and
other activities that change the flow of water into or out of the
lake affect the lake level. Some lake levels are actively managed,
often for power generation or flood control. Well-known examples of
managed waters include reservoirs along the Mississippi and St. Louis
rivers and lakes bordering Canada. Lakes that are managed to generate
electricity can fluctuate significantly throughout a year, particularly
during times of drought or flooding.
What happens when water
Fluctuations in water
level often cause erosion and sedimentation, may damage property and
upland vegetation, and can wash contaminants into lakes and rivers.
Access to roads and to water for recreation may be affected. Wells
and septic systems may develop problems when water levels change.
A decrease in water level can stimulate plant growth near shore, potentially
stabilizing sediments and increasing water clarity, but it can harm
fisheries by reducing spawning areas and raising water temperature.
What is the right level
for a lake?
Lakes, like people,
change over time. Given geological time, there is no "right"
level for a lake. Historically, the lake you are considering may have
looked vastly different than it does now. It may not be possible to
determine the historical level of your lake by looking at it, but
you could try checking local historical sources for photographs and
Who is responsible for managing
lake levels in reservoirs?
It depends on the
reservoir. Some reservoirs are managed by power companies. Lakes along
the border between the U.S. and Canada are managed by the International
Joint Commission. On inland reservoirs, the DNR maintains its own
dams, but a county or local government usually controls the reservoir
water levels. Some water behind a dam must be released at all times
to maintain river flow below the dam. Low flow periods are critical
for fish when riffle areas dry out, invertebrate populations
(food for small fish) decline, spawning areas decline, and the water
temperature rises. The U.S. Army Corps of Engineers has jurisdiction
over locks and dams on navigable waters.
Who owns the lake and lakebed?
We all own
Minnesotas lakes, but the state manages the waters. Waters
of the State include all surface or underground waters, except
surface waters which are not confined but are spread over the land
(Minnesota Statutes, Section 103G.005, subd. 17). All lakes, ponds,
marshes, rivers, streams, ditches, springs, and water from underground
aquifers, regardless of size or location, are considered Waters
of the State.
The State of Minnesota
owns the bed of the lake if it is navigable according to a federal
test based on whether the waters are used as highways for commerce
or travel. Lakebeds are also considered state-owned if they could
be used for commerce in their natural or ordinary condition, even
if they are not currently in use. Owners of adjacent land own the
bed of the lake or to the centerline of a stream if it is NOT navigable
and meandered. If it is NOT navigable and NOT meandered, the owners
of the streambed are indicated on individual property deeds.
Who can I contact if I have
questions or a problem related to lake levels?
Check your local telephone
listing, the Who to Contact
section of the Minnesota Shoreland Management Resource Guide Web site,
or the Web sites listed below for:
What are some additional
resources related to lake levels?
- Work That Can Be Done
Without a Protected Waters Permit. 1994. Minnesota Department of
Natural Resources, Division of Waters
- A Guide for Buying &
Managing Shoreland. 1988. Minnesota Department of Natural Resources, Division
- Streambank Erosion
a Greater Understanding. 1991. Minnesota Department of Natural Resources,
Division of Waters