Reflecting on Lakes
A Guide for Watershed Partnerships
What makes your lake special?
Lakes have different meanings to different people. Ask yourself and others in your
partnership if you value any of the following from your lake...
The solitude and reflection that contrasts the hectic pace of
Recreational value for skiing, boating or fishing.
Drinking water to area residents.
Flood protection for downstream residents.
Abundant wildlife habitat.
Irrigation water for crops, golf courses, and lawns.
Tourism (restaurants, shops, hotels, entertainment, marinas,
Others unique to your partnership's lake.
In fact some lakes are the focal
point for millions, and in some cases billions, of dollars worth of food, tourism,
transportation and recreation.
How protecting your watershed can improve your lake.
A high quality lake, valued for water supply, recreation and aesthetic appeal, can benefit
all watershed residents (and nonresidents alike) by providing a healthy place to play
and/or enjoy a quiet sunset. In other words, a high quality lake improves the quality of
the community's life.
Watershed residents, even those located a long distance from the lake, can benefit if
the lake serves as a drinking water supply. A healthier lake lowers the cost of drinking
water treatment. This savings to customers -- present and future -- can be immense.
Property values, not only on the lakeshore, but throughout the watershed community, can
benefit from a desirable lake.
Economic development resulting from increased tourism and industrial development can
increase the tax base for watershed communities. This could improve schools, roads and
Well maintained and protected wildlife habitat areas attract birds and animals that add
to the appeal of the lake and its watershed.
Let's get started...
The good news is that if you and your partners have come to consensus on the ways lake
users value your lake, you're already well on your way.
Six keys to protecting lakes
Valuing high quality lakes
Understanding the link between the lake and its watershed
Understanding in-lake processes
Recognizing and preventing threats to lake quality
Forming partnerships with lake-watershed members
Knowing where to go for help
Your next step is to begin to understand the characteristics of your particular lake
and its associated watershed. This will become the basis for developing the most
appropriate and effective management strategies for achieving your group's goals. (See Putting Together a Watershed Management Plan
for additional assistance.)
A lake is the reflection of its watershed (the land that drains -- eventually -- into
it) and the everyday actions that take place on the watershed. The importance of the
relationship between a lake and its watershed cannot be over emphasized when protecting,
managing or restoring a lake.
The lake-watershed "system" is a functioning unit with interacting
biological, physical, chemical and human components. If a lake suffers from problems such
as extensive weed growth or algal scum, fish kills, or filling in with sediments, often
the cause of the problem can be linked to a source or sources within the watershed.
The characteristics of lake-watershed interaction depend on a number of variables. Some
variables include the ratio of drainage area to lake area, how the land is used, the
climate, soils and geography, as well as existing conservation measures.
The interplay between these and other variables varies from region to region and even
from lake to lake. That's why each lake and its watershed are a unique system.
Sizes and shapes. The origin of a lake often determines the size and
other characteristics of the lake.
"Natural" lakes are those that were formed by geological
processes such as receding glaciers (kettle lakes), volcanoes and earthquakes, eroding
limestone (solution lakes) and river activity (oxbow lakes).
"Man-made" lakes, often referred to as impoundments or
reservoirs, are those that were formed by damming a drainageway, stream or river. Man-made
lakes can range in size and shape from the smallest farm pond to huge "run-of
the-river" reservoirs such as Lake Mead formed by the Hoover Dam or those found in
the Tennessee Valley. (For simplicity we refer to both "man-made" and
"natural" lakes as "lakes".)
Lake-watershed size relationship. If a lake is small relative to its
watershed, the potential is greater for the lake to fill in with sediment or be affected
by nutrients tied to the soil particles, than a large lake with a relatively small
Climate and soils. Lakes in areas with more rainfall and steep,
erosive, nutrient-rich soils will have greater potential for algae blooms and plant growth
than those in dry climates with infertile soils.
Topographic. In general, the greater the slope of the land in the
lake's watershed, the greater the potential of pollutants reaching the lake.
Wetlands. Adjacent wetlands often filter out pollutants before they
enter a lake, improving the water quality of the lake. Wetlands also provide habitat for
plants and animals.
The in-lake environment.
Understanding the relationship between the lake and its watershed is just the beginning.
In order to carry out appropriate actions for lake protection, it is also important to
understand key in-lake processes.
The in-lake environment is determined by a variety of factors including:
Volume of water flow into and out of the lake, or lake hydrology
Hydraulic residence time
Internal cycling of lake nutrients (particularly phosphorous and
Lake habitat for plants and animals
Lake Hydrology. Watershed features will have a great influence on lake
hydrology. The volume of water entering the lake via precipitation, groundwater flows,
surface land runoff, and streams in relation to the water exiting the lake via
evaporation, uptake by plants (transpiration), groundwater seepage, and surface streams
will determine the concentration of nutrients, sediments and other potential pollutants
within the lake.
Hydraulic Residence Time. The average period of time required to
completely renew a lake's water volume is called the hydraulic residence time. As an
example, if the lake volume is relatively small and the flow of water is relatively high,
the hydraulic residence time will be short. This can cause any nutrients -- which may lead
to algal blooms -- to be quickly washed out of the lake. On the other hand if the lake has
a long hydraulic residence time, algae have more of a chance to grow, bloom, and flourish
given adequate nutrient input and sunlight.
Lake Stratification. In most lakes, seasonal differences in temperature
between the air and water can cause the water to "turnover," or mix from top to
bottom. In other lakes, turnover can be caused by wind mixing the lake. The significance
of this phenomenon is that plant nutrients -- commonly stored in sediment on the lake
bottom -- can be stirred up and become fertile water for algae and aquatic plant growth.
Internal Cycling. Nutrients can also "cycle" in a lake when a
lack of oxygen at the bottom creates conditions that allow phosphorus to be released from
the sediment. This can stimulate algae and aquatic plant growth.
Lake Habitat. Lakes provide important habitat for many plants, animals,
fish and waterfowl. Many of these species are dependent upon the lake to complete their
life cycles. Lakes are often viewed only as places of recreation for many people, but to
wildlife and fish, lakes are essential for their survival.
Lake productivity stages.
In-lake factors combined with the lake-watershed relationship, determine how
"productive" a lake will be. The biological productivity of a lake is based on
the availability of plant nutrients and is referred to as the lakes "trophic"
condition. Extremely high or low productivity usually limits aquatic life. High
productivity leads to lots of algae and other aquatic plants. Low productivity leads to
very little aquatic life.
The trophic condition of lakes ranges from the least productive
moderately productive (mesotrophic) to highly productive (eutrophic). Hypereutrophic lakes
are the most productive of all.
The process of moving from an oligotrophic state to an eutrophic state, is a natural
process that can take thousands of years, as sediment from the watershed carries nutrients
slowly into the lake.
However, where human activity has affected a watershed, lake productivity can
dramatically increase over a relatively shorter period of time. This type of
eutrophication--as a result of watershed disturbance by humans -- is known as
What Threatens Lakes?
In addition to understanding how to make your lake-watershed healthier it is important to
understand how activities on the watershed and in or around the lake can threaten the
Major Threats To Lakes
The major threats to lake water quality in the United States are:
An overabundance of nutrients. This leads to algal blooms and excessive
plant growth which ultimately deplete oxygen supplies for fish and some other aquatic
Organic wastes. When organic wastes assimilate they cause a lack of
oxygen needed for fish and some other aquatic life to survive.
An overabundance of sediment. This "runoff" soil can fill
lakes and destroy habitat for plants and animals, as well as clog fish gills and smother
Metals and other organic chemicals such as polychlorinated biphenyls
(PCBs), contaminating fish and shellfish.
Rapid raising and lowering of water levels for power generation,
irrigation and other uses.
Although in-lake sources of pollutants like sediment and nutrients can exist, the primary
pollutant sources can be found in the watershed. Some include:
Agricultural management practices (activities) can lead to pollutants
like nitrogen, phosphorous, sediment, pesticides and organic matter entering the lake.
Runoff from pavement and lawns in urban areas picks up oil, metals,
bacteria (including E-coli), nutrients, and transports them through the storm sewer
Municipal sewage treatment plants in some cases can combine sewage with
stormwater in what is called a Combined Sewer Overflow (CSOs). This can lead to nutrients,
organic wastes, toxic household substances and other types of pollution.
Septic systems also contribute to lake pollution when they leak into
the shallow groundwater. This can also increase the load of nutrients, bacteria (including
E-coli) and other organic wastes.
Destruction of shoreline vegetation by construction, wave action, and
other activities, also increases chances of degrading lake quality as well as plant and
Atmospheric deposition, air pollution that is carried to the ground via
rain, is also a major threat in some areas of the country. Some types are referred to as
Urbanization of agricultural or forested land increases hard surfaces
like roads, parking lots, and rooftops. This increases the velocity of runoff reaching the
lake and causes streambank erosion, turbidity, and degraded wildlife habitats. Urban
runoff also carries oil, bacteria, nutrients, sediment, and metals into lakes.
Activities that threaten lakes.
Today many of the traditional polluting activities such as building and road construction,
commercial farming, and factory discharges have environmental requirements they must meet.
That's why it's the smaller scale activities that can be the most detrimental to a lake's
health. For example:
Leaking septic systems can contribute to nutrients and bacteria getting
into nearby waterways, streams and, eventually, the lake. Some nutrients can also be
carried through the shallow aquifer and reach spring-fed lakes. Either way, it can prevent
the lake's use for drinking water or recreational activities. It can also cause
overenrichment and algae blooms.
Using detergents containing phosphorous to wash boats, cars, and pets
in locations where the waste water can run off into the lake adds unneeded nutrients.
Overfertilizing your lawn or fertilizing at the lakeshore can also
contribute excess nutrients to the lake...potentially affecting drinking water and
recreational activities. (Remember a green lawn creates a green lake.)
Clearing vegetation near and on the lake shore removes a natural
buffering system which can help absorb nutrients and sediment runoff.
Using powerful outboard motors in shallow areas can churn up nutrient
laden sediments to support algae growth and destroy aquatic life.
Poorly maintained powerboat engines can leak oil and grease into the
"Clean" cropping practices that leave the fields clean in the fall
also leave soil vulnerable to snow, wind and rain. Nutrients and some herbicides attach to
the soil particle and are carried with it, ultimately, to the lake.
Mixing herbicides near wells or tile lines can leak chemicals into the
shallow groundwater which, ultimately, resurfaces into springs or streams which carry it
into the lake.
Treating manure like a waste rather than a fertilizer source can
contribute to nutrients and bacteria getting into nearby waterways, streams and,
eventually, the lake. Some nutrients can also be carried through the shallow aquifer and
reach spring-fed lakes. Either way, it can prevent the lake's use for drinking water or
recreational closings. It can also cause overenrichment and algae blooms.
Although it may seem that one house, one boat, or one farm alone cannot harm a lake,
the cumulative impacts of hundreds of boats, homes, and farms can add up to poor lake
quality. Every action you take affects the lake!
What you can do.
Because lakes and their watersheds are interrelated, watershed management is essential for
achieving and maintaining a healthy lake. In many cases, in-lake treatments (like algea
treatment) may also be required to achieve a desirable and balanced system.
Set a realistic goal.
As your group becomes more familiar with the lake, its link with the watershed, and the
desires of those who use the lake and live in the watershed; you and the group should
reevaluate the goals.
Let's assume your lake is naturally highly productive due to a combination of factors
that occur even without human presence, such as a warm climate, shallow lake, and highly
productive soils. In this situation, a plan that has a goal of returning the lake to an
oligotrophic, pristine clear water condition would be impossible.
Setting realistic goals based on existing conditions in addition to social and economic
considerations is a key to success.
Form a partnership between citizens and government agencies, as well as
anyone else with a vested interest in the lake and its watershed. Be sure to involve all
key players in the effort at the initial planning stages and continue to seek active
participation through implementation. This helps identify and avert future conflicts and
is often the key to success.
Remember, conflict can be healthy. Although it is not always possible
to avoid conflict in partnerships that involve groups with seemingly divergent interests,
finding and building on common goals -- a healthy, balanced lake and watershed -- will
help overcome differences. See the Managing
Conflict guide to better understand how conflict can be healthy. You may also
want to review Leading & Communicating
to brush up on your communication skills.
Clear communication and strong leadership will also help assure a
successful lake-watershed partnership.
What about existing lake associations?
Lake associations are voluntary organizations that usually are comprised of lakeshore
property owners. Often these organizations find participation and limited financial
commitment from those who do not reside on the lakeshore, but who may have an impact on
the lake quality. This is why it's very important to have a strong lake-watershed
Any other advantages?
Other advantages of voluntary organizations include the ability to:
Act more quickly than governmental-based organizations.
Detect and begin to address potential stresses to the lake
system before a
government representative does.
Represent members' interest to state and local governments.
Educate decision makers regarding land use in the watershed
and protection of
Act as an early warning signal for potential threats to the lake.
Undertake projects to help protect the lake.
Educate newcomers and visitors about the value of practicing
wise use of the
lake and surrounding watershed.
Sources of information.
To start down the road toward an effective local watershed partnership, you may want to
read some of these other guides from the Conservation Technology Information Center by
calling 765-494-9555. See our catalog
to order this online.
Getting to Know Your Watershed
Leading & Communicating
Putting Together a Watershed Plan
Groundwater & Surface Water: Understanding
Wetlands: A Key Link in Watershed Management
Guide to Information and Resources
Nonpoint Source Water Quality Contacts
The author acknowledges the following sources of information that
were used in developing this guide. You may also find these publications helpful.
Beyond the Estuary, The Importance of Upstream Wetlands in Estuarine Processes;
July, 1990, U. S. Environmental Protection Agency, Office of Water; 20W-5003.
Riparian Area Management, A Citizen's Guide; Lake County, Illinois
Stormwater Management Commission.
The Lake and Reservoir Restoration Guidance Manual, 2nd Edition; August
1990. U. S. Environmental Protection Agency, Office of Water; EPA-440/4-90-006.
Limnology, Second Edition; 1983. Wetzel, Robert G.; Saunders College
Answers to Common Lake Questions; September 1992. New Hampshire
Department of Environmental Services; Water Supply and Pollution Control Division; Biology
LakeSmarts, The First Lake Maintenance Handbook; November 1993.
McComas, Steve. The Terrene Institute. 1717 K St., Suite 801, Washington, D.C. 20006.
National Water Quality Inventory, 1992 Report to Congress; March 1994.
EPA 841-R-94-001. U. S. Environmental Protection Agency, Office of Water, 401 M St. SW,
Washington, D.C., 20460.
Where To Go For Help
Contact your local or state water quality agency, state lake association, local natural
resource agency, local conservation district or local extension office for assistance.
About this guide...
This guide is one of a series for people who want to organize a local partnership to
protect their watershed. This series will not solve all your problems. They were designed
to provide guidance for going through the process of building a voluntary partnership,
developing a watershed management plan and implementing that plan.
Because the characteristics of each watershed are unique, you may wish to select and
use the portions of this guide that are applicable to your particular situation.
Although the series is written for watershed-based planning areas, the ideas and
process can be used for developing other types of plans (such as wildlife areas) to match
the concerns of the partnership.
Regardless of the area, remember a long-term, integrated perspective - based on a
systematic, scientific assessment - can be used to address more than one concern at a
Please contact the Know Your Watershed program
at CTIC, 765-494-9555, for more information.
Special thanks to Susan Kaynor, Environmental Scientist, Coconut Grove, Florida, who
dedicated long hours to writing this guide. Without her help this guide would not be
The University of Wisconsin Cooperative Extension Service provided the illustrations
used throughout this guide. Watershed partnerships can obtain a copy of the full set of
illustrations (clip art) by calling 608-262-0020. Thank you.
Special thanks also go to the professionals (listed below) who carefully reviewed this
guide. Their experience and thoughtful guidance enriched it. Their time and insight is
US EPA, Region 5, Water Division
USDA, Natural Resources Conservation Service
Southwest Florida Water Mgmt. District
Northern Illinois Planning Commission
University of Wisconsin
Tennessee Valley Authority
South Dakota DENR
US EPA, Office of Wetlands, Oceans & Watersheds
USDA, Natural Resources Conservation Service
US EPA, Office of Water, Watershed Branch
The Know Your Watershed campaign is coordinated by the Conservation
Technology Information Center (CTIC), a nonprofit public/private partnership dedicated to
the advancement of environmentally beneficial and economically viable natural resource
systems. It provides information and data about agricultural and natural resource
management systems, practices and technologies. The center was established in 1982 under
the charter of the National Association of Conservation Districts.
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