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Caring forOur Lakes

Watershed and In-LakeManagement for

Connecticut Lakes

C O N N E C T I C U T D E P A R T M E N T O F E N V I R O N M E N T A L P R O T E C T I O NB U R E A U O F W A T E R M A N A G E M E N T

R e v i s e d 1 9 9 6

Caring for Our Lakes

Watershed andIn-Lake Management

for Connecticut Lakes

Caring for Our Lakes

Watershed andIn-Lake Management

for Connecticut Lakes

CONNECTICUT DEPARTMENT OF ENVIRONMENTAL PROTECTIONBUREAU OF WATER MANAGEMENT

Revised 1996

Copies of these publications are available at no chargefrom the Bureau of Water Management.

Telephone: 860 424-3716.

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FOREWORD

Caring for our lakes is important to the preserva-tion of natural resources, stimulation of economicgrowth, and elevation of the quality of life in ourstate. Lakes and ponds enhance our landscape and areused extensively for swimming, fishing, boating, andother forms of recreation. Money spent on recreation isimportant to local and state economies, and the highproperty values of lakefront homes augment tax revenuesof surrounding communities. These benefits deterioratewith a decline in lake water quality.

How should you care for your lake? First, you mustunderstand the external factors that impact water quality.You must answer questions such as — Where does thewater that flows into the lake come from? What pollutantsdoes that water carry? Identifying pollutant sources in thewatershed and halting or controlling that pollution so itdoes not enter the lake is called watershed management.

Second you must learn about the physical, chemical,and biological features of your lake. These characteristicsmake your lake unique. At the same time you shouldidentify real and potential problems that are causing con-cern for lake residents and users. These may include anovergrowth of aquatic plants, algae blooms, or excessivesedimentation. Dealing with these internal problems iscalled in-lake management. In many instances, the lackof watershed management has given rise to the need forin-lake management.

This booklet is designed to give you an overview of

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watershed and in-lake management methods. Some ofthese methods can be used by local individuals, business-es, lake associations, town officials, and other interestedparties. Other tasks may require the services of profession-al experts such as limnologists, environmental engineers,or resource managers. The Lakes Management Program ofthe Connecticut Department of EnvironmentalProtection (CT DEP) is a good place to start if you havequestions or need advice about management options. Theprogram maintains a list of professional firms that canconduct diagnostic studies and implement managementmeasures for your lake and watershed.

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INTRODUCTION

The booklet has three chapters. Chapter 1 provides ageneral background of lake ecology and describes typicalproblems faced by lake users and residents. This sectionencourages you to set community goals and to develop amanagement plan. Chapter 2 focuses on watershed man-agement activities that protect lake water quality fromnutrients, sediment, and other pollution. Best ManagementPractices (BMPs) for residential, urban and agriculturalwatershed protection are discussed. Chapter 3 describesin-lake management methods that relieve aquatic weedand algae growth problems.

Technical terms are italicized when they first appear inthis booklet, and are found in the glossary in APPENDIXA. APPENDIX B lists organizations and agencies to con-tact for additional information. Connecticut lakes areclassified in APPENDIX C.

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TABLE OF CONTENTS

Foreword v

Introduction vii

1. Background: How a Lake Changes 11.1 Taking Responsibility for Your Lake 11.2 Eutrophication:

The Crux of Lake Management 31.3 Problems Associated with Eutrophication 4

Algae blooms 4Aquatic weed beds 4Loss of water depth 4Dissolved oxygen depletion 5Special problems in artificial

lakes and ponds 51.4 Acidification 61.5 Seasonal Stratification of Lake Water 6

Summer stratification 6Fall overturn 7Winter stratification 8Spring turnover 8

1.6 Lake Classification 8Trophic state classification 8Water quality classification 10

2. Watershed Management2.1 A Lake and Its Watershed 11

Sources of pollution: point and nonpoint 12

Table of Contents vii

Managing nonpoint source pollution (BMPs) 142.2 Pollution Prevention (BMPs) 15

Septic systems 15Soil erosion 18Agriculture 21Woodland and timber harvesting 23Residential nonpoint pollution sources 24Urban runoff 25Washing vehicles 27Waterfowl 28Recreational beaches 29

2.3 Pollution Recovery (BMPs) 30Extended detention ponds 30Wet ponds 30Natural wetlands 31Artificial stormwater wetlands 31Infiltration trenches 32Infiltration basins 32Sand filters 32

3. In-Lake Management 343.1 The Appropriateness of

In-Lake Management 343.2 Managing Macrophytes 35

Mechanical removal of plants 38Cutting 38Raking 39Uprooting 39Lake bottom barriers 42Sediment removal 43Grass carp 45Aquatic herbicides 47Light limiting dyes 49Wintertime drawdown 50

viii Caring For Our Lakes

Weevil predation 513.3 Controlling Algae 52

Reducing phosphorus availability 52Buffered alum 54Hypolimnetic aeration 55Hypolimnetic withdrawal 55Artificial circulation 56Killing or directly removing algae 57Aquatic algicides 57Mechanical removal 58

Conclusion 59

AppendicesAppendix A 61Appendix B 66Appendix C 69

1

BACKGROUND:HOW A LAKE CHANGES

1.1 Taking Responsibility for Your Lake1.2 Eutrophication: The Crux of Lake Management1.3 Problems Associated with Eutrophication1.4 Acidification1.5 Seasonal Stratification of Lake Water1.6 Lake Classification

1.1 Taking Responsibility for Your LakeTaking responsibility

for the lake you use orlive near is the first steptoward effective lake care.If it is a private lake, youand your neighbors aredirectly responsible formaking managementdecisions concerning itswell-being. If the lake haspublic access, your responsibilities are shared with one ormore tax-supported public agencies. As a member of thepublic, your responsibility and input are important. Inmany cases it is crucial that you get involved becausepublic agencies do not have the resources to manage eachlake to the degree necessary for effective protection. It isyour passion for your lake that will ensure clean water forswimming, fishing, boating, and other uses.

2 Caring for Our Lakes

Learning about your lake and watershed is crucial tolake care. All lakes are essentially collectors of water fromthe surrounding watershed. Thus the quality of a lake isdefined largely by the quality of the water that flows intoit. If the watershed is farmed, the lake may be impactedby agricultural fertilizers, pesticides, and sediments. If thewatershed has urban or suburban areas, water runoff maycontain septic leachate, oil and gas, road sand, salt, andlawn fertilizers. Land development and forest cutting alsocan cause erosion and movement of sand, silt, and organicmatter to the lake.

Knowing how the land in your watershed is used andthe pathways of water into the lake provides valuableinformation for designing protection strategies. You alsoneed to know physical factors such as lake depth, shore-line characteristics, inlets, and outlets. Finally, you needto be aware of a process that occurs in all lakes and ponds—eutrophication. Eutrophication is a natural increase ofnutrients and sediments over time that can stimulateexcessive aquatic weed and/or algae growth.

It is crucial that the people responsible for a lake devel-op watershed and lake management plans to meet theirgoals. For lakes with eutrophication problems, goalsinclude controlling aquatic weeds or reducing algalblooms. Other goals may include developing recreationalopportunities, improving fishing, and enhancing aesthet-ic appeal.

The plan development process includes defining andranking problems, setting a timetable, securing funds,implementing solutions, and evaluating progress. Severallake groups in Connecticut have successfully implement-ed lake and watershed management plans and are reapingthe benefits of quality lakes. The primary purpose of thisbooklet is to help you plan the future of your lake.

Background: How A Lake Changes 3

1.2 Eutrophication—The Crux of LakeManagement

Eutrophication is a natural aging process that increasesaquatic weed and algae growth. Ultimately, in the laststage of eutrophication, the waterbody evolves into a wet-land — a swamp, marsh, or bog. The rate at which a lakereceives nutrients and sediments from its watersheddetermines the rate of eutrophication. Under natural con-ditions eutrophication occurs over a long period. A forest-ed watershed contributes minimal amounts of nutrientsand sediments, and takes centuries to change a lake’sappearance. The aging process speeds up considerably,however, when the amount of plant nutrients and sedi-ments that drain into a lake increases due to develop-ment, farming, and other human activities. The termcommonly used when eutrophication is accelerated bythese man-made conditions is cultural eutrophication.

Effects of cultural eutrophication can occur in a shortperiod of time, a few decades or less. Dissolved nutrients,including phosphorus and nitrogen, fertilize the waterenvironment and stimulate algae and weed growth.Sediment particles also carry nutrients that eventuallybecome available to aquatic plants in the lake. In addi-tion, sediments settling on the bottom make the lakeshallower. This makes the bottom closer to the surface,exposing more area to sunlight, thus expanding growingareas for rooted plants.

An important concept to keep in mind is the role ofthe limiting nutrient, that nutrient in the shortest supplyrelative to the needs of an organism. When the limitingnutrient is depleted, growth stops, even though othernutrients remain available. Any increase in the supply ofthe limiting nutrient results in a corresponding increasein growth, as any decrease in the supply results in adecrease in growth. The supply of the limiting nutrient


controls the growth of algae and aquatic weeds in a lake.Phosphorus is the principal limiting nutrient for thegrowth of algae. Phosphorus or nitrogen typically func-tions as the limiting nutrient for larger aquatic plants.

1.3 Problems Associated with EutrophicationCultural eutrophication can interfere with the use and

enjoyment of a lake and greatly impact the lake ecosys-tem. Typical problems associated with eutrophication arediscussed below.

Algae bloomsAlgae are microscopic plants that are vital components

of the lake ecosystem. Algae serve as sources of food andenergy for fish and other lake organisms. Excessive algaegrowths, however, occur as “blooms” that have a pea soupappearance and can form scums and mats on a lake’s sur-face. Algae blooms interfere with the enjoyment of a lake,and can affect both the taste and odor of water. Whenblooms die, the plant matter decomposes, depleting oxy-gen in lake waters. Such oxygen depletion can cause a fishkill. The presence of frequent algae blooms usually indi-cates that phosphorus levels in the water are high.

Aquatic weed bedsMacrophytes are large aquatic plants that, like algae, are

vital components of a lake ecosystem. They provide coverfor fish and food for wildlife. However, shallow water andtoo many nutrients can cause large, dense weed beds togrow. These can be a nuisance, interfering with swim-ming, fishing, and boating. Decomposition of the plantmatter may deplete oxygen levels, causing fish kills.

Loss of water depthSediments can come from the watershed and from


decaying algae and weeds in a lake. The buildup of sedi-ments in a lake causes a loss of water depth. Shallowerwater encourages excessive macrophyte growth.

Dissolved oxygen depletionFish and other aquatic animals depend on dissolved

oxygen for respiration. Bacteria and other microorganismsuse oxygen while decomposing organic materials. In lakeswith excessive amounts of organic materials, such asplant matter or waterfowl droppings, oxygen maydecline. A reduction of oxygen in deep, cold lake waterscan impair the health of trout and salmon, especially inthe summer. Severe dissolved oxygen depletion can resultin a fish kill. Loss of oxygen can cause internal nutrientloading by allowing phosphorus in the sediments to bereleased to the water.

Special problems in artificial lakes and pondsMany lakes and ponds in Connecticut are man-made,

formed during the construction of dams across streams orwetlands or with the excavation of basins in wetlands.Connecticut also has natural lakes and ponds that havebeen artificially deepened and enlarged by dammingexisting outlets. Both man-made and artificially deepenedlakes and ponds have water covering fertile wetland soilsor terrestrial soils that had previously supported produc-tive vegetation.

Although artificial lakes undergo eutrophication in thesame manner as natural lakes, they have a different start-ing point. Most artificial lakes do not start out with lownutrient levels; they are often enriched due to the fertilityof flooded wetland and upland areas. Improving condi-tions in these lakes can be very difficult because restora-tion may attempt to create conditions that never existed.


1.4 AcidificationAcidification of lakes is not currently an urgent concern

for Connecticut lakes. While there are sources of acidifica-tion, such as natural watershed soil and wetland acidifica-tion processes, soil acidification associated with water-shed reforestation, and acid precipitation, most lakes arewell buffered and acids are neutralized. Presently, no lakesin Connecticut are classified by the CT DEP as impairedby acid precipitation.

1.5 Seasonal Stratification of Lake WaterMost lakes in Connecticut with depths of twenty feet

or more stratify into temperature-defined layers duringthe summer and winter. This seasonal stratification isimportant in determining movement of nutrients andoxygen in the water column.

Summer stratificationDuring the summer, surface water becomes less dense

as it warms, separating it from colder, denser, bottomwaters. Deep lakes stratify into three distinct thermalzones:

• Epilimnion• Metalimnion or Thermocline• Hypolimnion

EPILIMNION

METALIMNION or THERMOCLINE

HYPOLIMNION

Typical summer stratification of a deep lake.


The top layer, epilimnion, is the warmest layer of water.Aquatic weeds and most summer algae blooms occur in thiszone. Atmospheric diffusion and photosynthesis continuallysupply oxygen to the epilimnion. The metalimnion, or ther-mocline, is a transition zone that separates the epilimnionfrom the hypolimnion. The hypolimnion, bottom layer, con-tains the coldest water and is often void of oxygen.

Water temperature, biological activity, and weatherconditions influence the distribution of dissolved oxygen.During the summer, the cold bottom waters of low nutri-ent (oligotrophic) lakes generally contain oxygen and littleplant growth. Whereas, in nutrient rich (eutrophic) lakes,removal of dissolved oxygen occurs in the hypolimnionas a result of the decay of organic material, such as algaethat has died and settled on the bottom. This oxygen can-not be replaced from the atmosphere in the summerwhen a lake is thermally stratified. Fish habitat is thenlost and only organisms that can tolerate anaerobic, oroxygen-free, conditions live in the hypolimnion. If alloxygen is removed, phosphorus and ammonia nitrogenfrom the sediments are released into the hypolimnion.These nutrients can reach the epilimnion and stimulatean algae bloom if wind mixes the water or during falloverturn (refer to the “Fall overturn” section).

Lakes that flush quickly, such as ponds, shallow lakes,and those created by damming rivers termed impound-ments, offer exceptions to the typical stratification pat-tern. Within such water bodies, surface waters may beonly slightly warmer than bottom waters or temperaturesmay be uniform throughout the water column.

Fall overturnIn the late summer, the epilimnion cools, thereby

becoming denser, and the lake mixes from the surface tothe bottom. During fall overturn, the temperature and


nutrient levels become uniformly mixed throughout thewater column and dissolved oxygen is replenished.

Winter stratificationWinter stratification differs from summer stratification

in that the coldest waters are found at a lake’s surfacerather than at the bottom. Although cold water holdsmore oxygen, it often becomes depleted when ice blocksaccess to air and reduces light penetration needed forphotosynthesis. In shallow eutrophic lakes, this can resultin winter fish kills under the ice.

Spring turnoverWhen ice melts, wind mixes the surface and bottom

waters, resulting in spring turnover. The lake remainsphysically and chemically uniform until the surface watersbegin to warm at the onset of summer stratification.

1.6 Lake ClassificationTwo lake classification systems are used by the CT DEP:

the trophic state classification and the water quality classi-fication. The trophic state classification system is based onthe biological productivity of a lake and its relation tolake uses. The water quality classification system is basedon the historical and designated use of a waterbody.

Trophic state classificationScientists have developed a classification system todescribe phases of eutrophication: oligotrophic,mesotrophic, and eutrophic. These phases are subdividedinto six states used to evaluate water quality:

• Oligotrophic• Early Mesotrophic• Mesotrophic


• Late Mesotrophic• Eutrophic• Highly Eutrophic

Oligotrophic lakes are in the early phases of eutrophi-cation. They are deep, clear, infertile lakes with little algaeand few rooted aquatic plants. Bottom waters are welloxygenated and sediment accumulation is low.Oligotrophic lakes therefore are prime recreational lakes.Mesotrophic lakes are also good recreational lakes, butusually exhibit some water quality degradation and useimpairment. Eutrophic lakes are usually relatively shallowwith fertile, turbid waters. They have poorly oxygenatedbottom waters, substantial sediment accumulations, anddense blooms of algae and aquatic plant beds. Theseattributes can seriously limit recreational uses.

These classifications can be used to compare the waterquality of lakes and to establish benchmarks for short andlong-term trends. A list of Connecticut lakes classifiedaccording to trophic state by the ConnecticutDepartment of Environmental Protection is in AppendixC. A lake classified as eutrophic is not undesirable forall types of recreation, and efforts to manage the lakeshould not be discouraged. Similarly, the classificationof a lake as oligotrophic should not engender compla-cency.

Additional Information on Trophic State ClassificationsTwo reports produced by the CT DEP on lake trophic

state classifications, “Trophic Classification of Forty-nineConnecticut Lakes” and “Trophic Classification ofSeventy Connecticut Lakes,” can be obtained from the CTDEP, Maps and Publications Sales Office (860) 424-3555.


Water quality classificationThe CT DEP also uses another classification system for

water quality. This system is separate from and serves adifferent function than trophic state classification. Thesewater quality classifications are based on historical anddesignated uses and identify the criteria necessary to sup-port those uses. Most recreational lakes in Connecticutare categorized as either Class A or Class B waters. Class Awaters are recreational waters suitable for fishing andswimming that may not receive treated wastewater dis-charges. Class B waters are recreational waters suitable forfishing and swimming that may receive treated waste-water discharges. A dual classification, such as B/Adescribes the existing condition (first letter) and theadopted goal (second letter). A few recreational lakes inConnecticut are Class AA waters, indicating tributaries todrinking water supplies.

Additional information on water quality classificationsLake water quality classifications can be obtained from

the CT DEP water quality classification maps. CT DEPleachate and wastewater discharge source maps, availablefrom the CT DEP, Maps and Publications Sales Office(860) 424-3555, provide additional information on cur-rent and historical pollution sources.

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Watershed Management

2.1 A Lake and Its Watershed2.2 Pollution Prevention (BMPs)2.3 Pollution Recovery (BMPs)

2.1 A Lake and Its WatershedA lake’s watershed consists of all land areas that drain

directly into the lake and those watercourses that flow tothe lake. Water entering the lake, especially after a storm,typically carries a load of nutrients, sediments, and otherpollutants. Nutrients are important in the eutrophicationprocess because they fertilize the water and stimulategrowth of aquatic weeds and algae. Sediments settle tothe lake bottom, creating shoals and decreasing lakedepth. Other pollutants, such as pathogens, heavy metals,

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and hydrocarbons can also cause problems with aquaticlife and water use.

The health of a lake depends greatly on the quality ofthe incoming water. Watershed topography, soil fertility,soil erosion, vegetation, and human activity all affect thisquality, and, therefore, the lake itself. The goal of water-shed management is to prevent pollution from movingoff the land and into the lake. Effective watershed man-agement is the foundation for all lake preservation andrestoration efforts.

Sources of pollution: point and nonpointSources of lake pollution are divided into two broad cate-gories — point and nonpoint. Point sources are concentrat-ed discharges that enter a watercourse at a single point,most commonly a pipe. An example of a point source is adischarge from a wastewater treatment plant. Pointsources affect only a few lakes in Connecticut, impound-ments on rivers that receive discharges of treated waste-water. The strict standards of state and federal water pol-lution laws regulate these sources to prevent pollution.

Nonpoint sources are diffuse, occurring primarily asstormwater discharges from land areas within the water-shed. Every lake and pond in Connecticut is affected bynonpoint pollution sources. Although a single nonpointpollution source may not noticeably affect a lake, thecumulative effect of many nonpoint sources in the water-shed can be great. In Connecticut most nonpoint pollu-tion sources are tied to human activity and development.They may include septic systems, agriculture, lawns andgardens, stormwater drainage systems, and developmentthat exposes land to erosion. Other sources may includewaterfowl, household pets, recreational beaches andpoorly managed timber harvesting operations.

Typical nonpoint pollutants include the following:

Watershed Management 13

• NUTRIENTS—Most important are phosphorus andnitrogen because they stimulate aquatic weed andalgae growth. Sources include septic systems, agri-cultural runoff, and urban/suburban landscaperunoff, waterfowl, and pets.

• SOLIDS—These include both sediments and float-able wastes. Sources can include eroding construc-tion sites, stream banks, roadway runoff, and agri-cultural lands. Sediments from eroding land in thewatershed increase nutrient and organic matter in alake. When deposited, solids make the lake shallow-er and destroy the natural bottom habitat.Suspended solids cloud the water and interfere withorganism respiration and digestion.

• PATHOGENS—Bacteria and viruses from animalwastes, failing septic systems, and other sourcespose health risks.

• HEAVY METALS—Lead, copper, cadmium, zinc, mer-cury, and chromium can come from marinas, auto-mobiles, industrial waste and atmospheric pollution.Deposits in a lake can be toxic to aquatic species.

• HYDROCARBONS—Petroleum based substances,including oil and grease, are toxic to sensitiveaquatic organisms. Runoff from parking lots, road-ways, and marinas is a typical source of these pollu-tants in a watershed.

• PESTICIDES—This category includes lawn, garden,household, and commercial pest control chemicals.These pollutants can be toxic to many organisms ina lake.

• HUMIC SUBSTANCES—Grass clippings, leaves, andother plant material deposited in a lake from land-scaping practices results in problems when theydecompose. Dissolved oxygen is lowered, whichaffects the respiration of aquatic organisms and


allows nutrients to be released from the sediments.And, these organic materials break down formingmuck on the lake bottom.

Managing nonpoint source pollutionThere are two primary approaches to managing non-

point pollution sources in the watershed: pollution pre-vention and pollution recovery. The best, most economi-cal approach is pollution prevention. That is, preventingpollutants such as those listed in Section 2.11 from mov-ing off upland sites and into streams or groundwater thatdrains into the lake. Pollution recovery is the interceptionof runoff and reclamation of pollutants before they reachthe lake.

Best Management Practices (BMPs) are methods found tobe the most effective, practical means for reducing pollu-tion. Implementation of BMPs occurs primarily at thelocal level by private property owners and the local gov-ernment according to a watershed management plan. Thesize of a watershed will determine the scope of the plan. Inlarge watersheds management is complex because a num-ber of different towns or even states may be involved.Some BMPs may be implemented on a voluntary basis,such as the proper application of lawn fertilizers by ahomeowner. Other BMPs may be implemented on a regu-latory basis, such as erosion controls required for construc-tion sites by town permits in accordance with state laws.Whatever the situation, BMPs are the primary methodsused to implement a watershed management plan.

Members of lake associations should become knowl-edgeable about BMPs, and communicate this informationto property owners and town officials. Many lake associa-tions in Connecticut use newsletters, workshops, andhandbooks for this purpose. In addition, lake associationscan promote the use of BMPs by participating in local


public meetings and by commenting on permit applica-tions under review by town commissions.

Additional information on nonpoint source managementThe 1994 CT DEP report “Connecticut’s Nonpoint

Source Assessment and Management Plan” provides anoverview of the statewide nonpoint source managementprogram. It is a general guide to pollutants, their sources,impacted resources, management goals, strategies andpractices. To obtain a copy of this report call the CT DEPBureau of Water Management, Planning Division (860) 424-3020.

2.2 Pollution PreventionBMPs are a key aspect of pollution prevention.

Common nonpoint pollution sources in lake watershedscan be septic systems, soil erosion, agricultural areas with-out BMPs, residential landscaping, urban runoff, car wash-ing, waterfowl, recreational beaches, and poorly managedtimber harvesting operations. The following sections dis-cuss BMPs for dealing with these pollution sources.

Septic systemsIndividual septic systems are often used for sanitary

wastewater treatment for homes around Connecticutlakes. A septic system includes a house sewer, a septictank, a distribution system, and a leaching field. Sewage isdelivered to the septic tank via the house sewer. In theseptic tank, solids separate from liquids. Heavy solids set-tle to form a sludge blanket; light solids float to form ascum layer. The liquid from the septic tank flows to theleaching system where soil bacteria decompose wastematter. After treatment in the leaching system, waste-water effluents flow into the soils below the surface.


BMPs for septic systems include proper siting, design,installation, operation, and maintenance. Septic systemsmust provide for the sanitary degradation of wastewatersinto simple chemical substances, including soluble phos-phorus and nitrogen compounds. If not managed proper-ly, a septic system can fail, resulting in the backflow ofwastewaters into the house, or the breakout of waste-waters on the ground. A septic system failure is a publichealth hazard that demands immediate correction.Eliminating the health threat eliminates a possible sourceof nutrients to a nearby lake.

Local health officials are responsible for seeing thathomeowners correct failing septic systems. Single andscattered failures can often be repaired on-site. However,widespread failures may require a community wastewatermanagement plan. A lake association should notify localhealth officials about suspected septic system failures, andmonitor the results of investigations.


When seasonal cottages around a lake are converted topermanent homes, local public health officials areresponsible for evaluating septic system upgrades toassure conformity with the state Public Health Code.Cottage conversions are usually subject to local buildingpermits and zoning approval, providing a means for localauthorities to require septic system upgrades.

The following septic system BMPs should be followedby property owners in a lake watershed:

• Pump out septic tank solids on a regular basis.Sludge levels in the septic tank should be checkedannually and pumped when sludge fills half thetank, usually every two to three years for perma-nent homes, five to six years for seasonal cottages.If solids are not removed from the tank, they willwash into and clog the leachfield.

• Do not use the septic system for disposal of kitchenwastes. Ground-up garbage from a kitchen garbagedisposal can overburden a septic tank.

• Do not flush strong cleaning agents such as draincleaner, bleach, paint, or other household chemi-cals into a septic system. These chemicals may killthe beneficial microorganisms needed to breakdown wastes.

• Use nonphosphate laundry detergents. This canreduce the amount of phosphorus passing throughthe septic system and into the environment 30 to40 percent.

• Conserve water and give the septic system time to“rest” after heavy use.

Additional information on septic systems“Septic Systems Manual: A Guide to On-Site Subsurface

Sewage Disposal for Local Land-Use Officials,” publishedby the CT DEP in 1985, is available at the CT DEP Maps


and Publications Sales Office (860) 424-3555. This guideexplains the legal and technical aspects of on-site septicsystem design and installation. The manual provides abrief explanation of the process of sewage treatment in aseptic tank, leachfield, and surrounding soils. This manu-al should be consulted by local commissions whenreviewing applications for planning, zoning, and wetlandpermits that involve the installation of new septic sys-tems within the lake watershed.

Soil erosionSoil erosion is the wearing away of land by wind,

water, ice, and gravity. In lake watersheds, soil erosioncaused by water running off the land and by wave actionon the shore are important concerns. Natural erosionoccurs at a slow and generally uniform rate. However, dis-turbance of land surface by human activity eliminates theprotection provided by natural vegetation, exposing thesoils to excessive erosion. The exposed soil can becomehard, reducing its infiltration capacity and resulting ingreater runoff.

The severity of erosion is influenced by soil type, slopeof land, type of vegetative cover, rain, snow, and proximi-ty to a watercourse. Severe natural erosion can occur onland with steep slopes and along stream banks and lakeshorelines. Common man-made sites of erosion includeconstruction sites, roadway embankments, roadwaydrainage ditches, and cultivated fields. Construction siteerosion can be particularly severe; research has shownthat soil erosion from construction sites may be ten to100 times greater than erosion from agricultural land ofthe same size, slope, and soil type. Because the demand todevelop lake properties is high, construction site erosioncan play a major role in lake eutrophication.

The effectiveness of erosion controls for construction


sites in the watershed should be closely monitored. Anyincidents of water turbidity, siltation, or sedimentobstruction in the lake or its tributary watercoursesshould be reported to the town zoning enforcement offi-cer or wetlands enforcement officer for inspection andcorrective action.

Stream bank erosion has an immediate and oftensevere impact on lake water quality. Activities that disturbland surfaces should be avoided in these areas. Bank slop-ing, riprap, vegetation, jetties, fencing, and removal ofobstructions to stream flow are examples of appropriatepreventive measures.

Buffer strips, a universal BMP, control stream bank ero-sion by keeping strips of natural vegetation along streamcorridors. Vegetated buffer strips protect the soil and alsointercept runoff, thereby removing sediment and phos-phorus. A lake association should support the use ofBMPs on stream bank properties in their lake’s watershed.

Wave action can also erode shorelines. Lakefront prop-erties with vulnerable shorelines should consider the fol-lowing BMPs:

• maintain vegetated buffer strips• leave rocks and boulders undisturbed in order to

diffuse wave action• employ strict erosion and sediment controls for

construction activities

Legal requirements on erosion controlsThe Soil Erosion and Sediment Control Act, Sections

22a-325 through 22a-329 of the Connecticut GeneralStatutes requires towns to adopt erosion and sediment con-trol plan regulations for disturbed areas greater than one-half acre. The town regulations must provide for certifica-tion of the technical adequacy of the plans and provide forinspection of the measures installed pursuant to the plan.


The town may consult a County Soil and WaterConservation District (see Appendix B) for technical reviewof plans. Single family dwellings that are not part of a sub-division are exempt from town erosion and sediment con-trol regulations by state statute, and cannot be controlledby the town under the authority of state erosion and sedi-ment control laws. However, construction of single familyhomes within the town’s regulated wetland and water-course zone may require installation of sedimentation anderosion controls under local wetland regulations.

Erosion from construction activities may also regulatedby DEP’s Bureau of Water Management. Constructionsites of five acres or more must have plans for controllingstormwater and dewatering wastewaters generated fromthe site approved by DEP before construction can com-mence.

Additional information on soil erosionErosion from construction sites can be controlled by

using BMPs found in “Guidelines for Soil Erosion andSediment Control,” prepared by the Connecticut Councilon Soil and Water Conservation. This technical manualassists government officials, developers, engineers, con-tractors, and others in selecting measures to prevent ero-sion and sedimentation. Measures discussed in detailinclude site planning; vegetative controls, such as seed-ing, sodding, and tree planting; nonstructural controlssuch as hay bale checks, mulching, land grading, and traf-fic control; and structural controls such as diversions,riprap, and sediment basins. These guidelines should beused by government officials, developers, engineers, con-tractors, and others in designing structural measures forerosion and sediment control. This manual may beobtained through the CT DEP Maps and PublicationsSales Office, (860) 424-3555.


AgricultureIn many lake watersheds, agricultural lands such as

croplands, grazing lands, feedlots, and tree nurseries canbe potential nonpoint pollution sources of sediments andnutrients. Generally, nonpoint source pollution is man-aged by the individual farm owner/operator working withstate and federal technical and financial assistance pro-grams. The following are BMPs for each of these commonnonpoint pollution sources.

BMPs for croplands include:• conservation tillage• contour farming• contour strip-cropping• no-till seeding• terracing• vegetative buffers• winter cover crops• nutrient management• riparian area protection• integrated pest management

Feedlot BMPs include:• paving• stormwater management• runoff treatment

Grazing land BMPs include:• terracing• fencing to protect wetlands and watercourses• rotation grazing

Animal waste BMPs include:• diversion and treatment of stormwater• manure management


Nursery BMPs include:• contour planting• cover crops• nutrient management• integrated pest management

Additional information on agricultureIn 1993, the CT DEP published “Manual of Best

Management Practices for Agriculture” for Connecticut’sAquifer Protection Program. This manual containsdetailed information on agricultural BMPs needed to pro-tect the quality of groundwaters used as public drinkingwater supplies and is applicable to lake watershed man-agement programs. Copies of this manual are available atthe CT DEP Maps and Publications Sales Office, (860)424-3555. Several government agencies have programs toassist in the implementation of agricultural BMPs (SeeAppendix B):• The U.S. Department of Agriculture (USDA) Natural

Resource Conservation Service (NRCS), a federalagency, provides technical assistance to farmers onplanning and implementing agricultural BMPs anddeveloping farm resource management plans forindividual farms.

• The USDA Farm Services Agency, also a federalagency, assists in funding BMP projects undertakenby individual farmers.

• The University of Connecticut (UCONN) CooperativeExtension Service, a state agency, provides informa-tion and education to farmers.

• The Connecticut Agricultural Experiment Station,also a state agency, performs BMP research anddemonstration projects.

• The county Soil and Water Conservation Districts(S&WCD) are an important communication link


between government programs and the agriculturalcommunity.

Woodland and timber harvestingAn acre of properly managed woodland in a lake water-

shed contributes much less phosphorus to the lake thanan acre of residential land in the same location. However,poorly managed harvesting of timber and firewood cancause serious erosion and sedimentation.

Legal requirements on timber harvestingTown governments may regulate timber harvesting

through local inland wetlands and watercourses regula-tions. The statutes that give municipalities this authorityallow towns to regulate clear cutting of timber in inlandwetlands. CT DEP’s Division of Forestry is in the processof developing regulations through the Forest PracticesAct. This program will require licensing of forest practi-tioners and review of commercial timber harvests.

Additional information on timber harvestingThe CT DEP Division of Forestry distributes a 1990

guide, “Timber Harvesting and Water Quality inConnecticut — A Practical Guide for Protecting WaterQuality While Harvesting Forest Products.” For moreinformation, call the CT DEP Division of Forestry, (860)424-3630.


Residential nonpoint pollution sourcesFertilizers that are commonly applied to lawns, home

gardens, and ornamental shrubs and trees contain theplant nutrients nitrogen, phosphorus, and potassium. Ina lake watershed, these nutrients from fertilizers mayenter the lake, thereby fertilizing aquatic plant growth.

Residents in lake watersheds should use fertilizers judi-ciously or not at all. If used, the type of fertilizer shouldmatch the specific needs of the soil and the plants beinggrown. The correct type and amount of fertilizer can be“prescribed” through a soil sample analysis conducted bythe UCONN Cooperative Extension Service. Soil testingkits can be obtained for a nominal fee from them at(860)486-2928.

The timing of fertilizer applications is important.Applications should be avoided in the late summer andfall when plant growth has ended. Furthermore, fertilizersshould not be applied if heavy rain is forecast. Nutrientsnot captured by plants are likely to be transported off theproperty during rainstorms.

Leaves, grass clippings, and other wastes from lawnsand gardens are rich in nutrients and organic matter.When washed into a lake, they increase lake sedimenta-tion and release plant nutrients. An important BMP is tocompost such wastes and recycle the compost as a soilconditioner and fertilizer. Composting sites should be asafe distance from the lakeshore, tributary watercourses,and stormwater drainage systems. In addition, woody


wastes should be chipped and reused as landscapingmulch or disposed of in a municipal brush disposal site.

Excrement from household pets, especially dogs, isanother potential source of lake pollution. Pet manurecontains organic matter, nutrients, and bacteria that canbe easily transported from paved surfaces to lake watersby stormwater runoff. An obvious BMP is to collect andproperly dispose of pet droppings. Some Connecticuttowns have adopted ordinances requiring such action;leash laws prohibiting pets from unsupervised roamingare also helpful in lake communities.

Urban runoffMany types of water pollutants accumulate on side-

walks, streets, driveways, parking lots, and other pavedareas. Leaves, branches, litter, animal excrement, salt,sand, and fluid leaks from motor vehicles accumulateduring periods of dry weather. Wastes such as used motoroil, radiator fluid, grass clippings, animal excrement, andcar wash wastewater is sometimes improperly discardeddown stormwater drains. Rainfall and melting snow,known as stormwater runoff, transport these materialsand contaminate watercourses with nitrogen, phospho-rus, sediments, decomposable organic matter, hydrocar-bons, heavy metals, pathogenic bacteria, and road salts.

Many BMPs can be implemented to manage urbanrunoff. Source controls include the following:

• regulatory programs to control litter• regulatory programs to prevent improper disposal

and discharge of wastes in stormwater systems andto require removal of animal excrement from pavedsurfaces

• maintenance of paved surfaces, including street andparking lot sweeping and repair of eroding pave-ment areas


A comprehensive urban runoff plan should be devel-oped for a lake watershed with appropriate measures forspecific sources of pollutants. Lake associations shouldimplement pollutant controls at their sources as well asthrough cooperation with local officials and private prop-erty owners.

Town regulations requiring stormwater runoff controlplans are effective. Stormwater control measures shouldbe incorporated into site development plans so thaturban runoff BMPs become an integral component of per-mitted land use activities.

Legal requirements on stormwater dischargesThe state of Connecticut issues three permits concern-

ing stormwater. One covers construction activities dis-turbing more than five acres; the other two regulatestormwater discharges from industrial or commercialfacilities (Section 22a-430b of the Connecticut GeneralStatutes).

Additional information on stormwater BMPsThe U.S. Environmental Protection Agency publication

“Urban Targeting and BMP Selection” presents anoverview of BMPs for urban stormwater management.BMPs are categorized as source controls, detention basins,infiltration basins, and vegetative controls. For copies ofthis document, call the U.S. Environmental ProtectionsOffice, Washington, D.C. (202) 833-8317.

The Metropolitan Washington Council of Governments,(202)962-3256, offers “A Current Assessment of Urban BestManagement Practice,” a valuable source of BMP informa-tion. The CT DEP Maps and Publications Sales Office,(860)424-3555, has another helpful publication, “GuidanceDocument for Assessment of Non-Point Sources ofPollution in Urbanized Watersheds in Connecticut.”


Washing vehiclesThe direct discharges of soapy wash water from car

washing into lakes and their tributaries should be pre-vented. Wash waters can transport sand, oil, and phos-phorus from soaps and detergents that degrade the waterquality of a waterbody. Even nonphosphate “biodegrad-able” soaps should not be allowed to enter surface watersdirectly, as they can be toxic to aquatic organisms at lowconcentrations and cause unsightly foaming.

Connecticut law requires the obtaining of a permit forthe discharge of wash water from vehicle washing, regard-less of volume or location, including charity sponsoredcar washes. Acceptable disposal options for vehicle washwaters include:

• wash cars in an area where all wash water enters amunicipal sanitary sewer for proper treatment

• for individual cars, wash in a grassy area largeenough to contain all wash water and then allow itto seep into the soil

• have a commercial car wash operator host the eventat a permitted facility

Additional information on washing vehicles“Guidelines for Disposal of Vehicle Washwater” is

available from the CT DEP Bureau of Water Management,Permitting, Enforcement and Remediation Division, (860)424-3018.


WaterfowlExcrement from Canada geese can be a troublesome

source of enrichment of lake waters with phosphorus,nitrogen, and decomposable organic matter. Since thelate 1970s, large flocks of Canada geese have been a prob-lem at several Connecticut lakes. At two lakes with largewinter flocks, the phosphorus from the bird droppingswas estimated to be equivalent to 50 to 70 percent of theannual phosphorus input from the lake watershed. Asorganic matter in the droppings decomposed the follow-ing summer, these lakes experienced early and intenseoxygen depletion setting the stage for additional nutrientreleases from lake sediments. Recently, similar concernshave been raised about gulls.

The presence of geese and gullsdepends on many factors, includingweather patterns, local climate con-ditions, availability of food supplies,hunting pressure, and flock behav-ioral patterns. Often habitat preferredby these birds is unknowingly creat-ed when wooded areas are converted

to residential lawns adjacent to a lake. If large flocks ofwaterbirds are contributing to eutrophication, govern-ment bird control experts should be consulted due totheir jurisdiction over these wildlife populations.Techniques to manage birds depend on lake size, type ofbird, proximity of human habitation, and feeding areasand may require federal permits before initiating.Techniques include the following:

• construction of fences, walls or buffer strips ofshrubs along lake shorelines prohibits easy move-ment in and out of the water for geese

• hunting in eligible areas• harassment scarecrows and other foreign objects,


automatic exploders, flashing lights, balloons, andchase dogs

Additional information on waterfowlThe USDA, Animal Damage Control, 463 West Street,

Amherst, MA 01022, (413) 253-2403 offers more infor-mation.

Recreational beachesErosion by wave action and stormwater runoff may

wash sand from recreational beaches into lakes. Lost sandis usually replaced with new sand, which is again lost andreplaced. As the cycle continues, sand from the beachaccelerates the filling-in of the lake. Beaches should bedesigned to have sand stabilized by vegetation and retain-ing walls. When feasible, dry dredging can recapture sandwashed into the lake.

Washed sand, sand that has all fine particles removed,should be used for beaches. One method to test if sand issuitable for a beach is to place a handful in a jar of water.If the sand leaves the water turbid after shaking the jar,the sand should not be used for beach sand.


2.3 Pollution RecoveryBMPs are important to pollution recovery. Common

pollution recovery techniques include designing or utiliz-ing extended detention ponds, wet ponds, natural wet-lands, artificial stormwater wetlands, infiltration trench-es, infiltration basins, and sand filters. The followingsections discuss such pollution recovery techniques.

Extended detention pondsExtended detention ponds are designed to collect and

retain stormwater runoff for a period up to twenty-fourhours so that pollutants such as sediments, phosphorus,and organic matter can be removed from runoff before itenters a lake. The ponds are normally dry between stormevents. Sometimes extended detention ponds areenhanced with plunge pools near the inlet and a microp-ool at the outlet. These enhancements help prevent clog-ging and resuspension problems. Debris and sanddeposits can quickly accumulate and periodic removal isessential to keep the pond functioning properly.

Wet pondsConventional wet ponds are

designed to have a permanentpool of standing water.Pollutants, such as suspendedsediments, nutrients, and heavymetals, are removed by gravita-tional settling, aquatic plantuptake, and decomposition.These types of ponds can beenhanced by designing a fore-bay to help trap incoming sedi-ments and by establishing a wetland around the perime-ter. If properly maintained with regular sediment cleanout, wet ponds can function for more than twenty years.


Natural wetlandsWetlands serve as buffers between land and water.

They protect lakes by moderating surface water flow,slowing nutrient transport, and removing suspended sedi-ments and other contaminants from stormwater runoff.Protection of natural wetlands is a priority for lake water-shed management.

During the spring and summer, growing wetlandplants remove significant amounts of nutrients fromoverlying waters. During the fall and winter, wetlandsrelease nutrients as their vegetation decays. In this waywetlands help delay the transport of nutrients until afterthe growing season when they are unlikely to contributeto algae blooms and weed growth. Wetlands also controlflooding and soil erosion by retaining water during peri-ods of high runoff, releasing the water gradually.

To preserve these valuable functions, wetlands must bekept in their natural states. Alteration of a wetlandreduces these buffering functions, contributing to thedegradation of downstream lakes. A lake watershed man-agement program should include participation in atown’s wetland permit process, monitoring permit appli-cations, and providing commentary on proposed wetlandactivities.

Artificial stormwater wetlandsStormwater wetlands are constructed to create a water

environment for the growth of wetland plants. Pollutantsare removed from incoming water by vegetative uptakeand settling. This is an effective BMP, but time and caremust be taken to establish desired species. These wetlandscan be enhanced with design elements such as a forebayand landscaping.


Infiltration trenchesInfiltration trenches are shallow, excavated trenches

that have been backfilled with stone. This creates anunderground reservoir for intercepted runoff water. Thewater gradually filters through the bottom of the trenchinto the subsoil. To prevent clogging, many infiltrationtrenches are designed with a pretreatment system toremove sediment and oil.

Infiltration basinsInfiltration basins function similarly to infiltration

trenches, but are designed to be impoundment basins.Stormwater runoff is intercepted, retained, and allowed tofilter through the bottom into the subsoil. Unfortunatelyinfiltration basins clog easily and effective maintenance isusually difficult.

Sand filtersSand filters have been effective in parts of the country.

The first flush of stormwater runoff is diverted into a self-contained bed of sand. The runoff is strained throughsand, collected in underground pipes, and transportedback into a stream or channel. Sand filters have shownhigh rates of removal for sediment and heavy metals, andmoderate removal rates for nutrients. Enhanced designsinclude the incorporation of layers of peat, limestone,and topsoil into the filter to increase pollutant removal.

Legal requirements on wetlands developmentThe Inland Wetlands and Watercourses Act, Sections

22a-36 through 22a-45 of the Connecticut GeneralStatutes, protects wetlands through the regulation ofdevelopment activities in wetland areas. Every town has aboard or commission that administers a wetlands permitprogram and acts on permit applications for regulated


activities in lake watersheds. This is particularly impor-tant for wetlands adjacent to lakes or their tributarywatercourses. In addition, the Commissioner ofEnvironmental Protection may intervene in municipalproceedings to enforce statutes and ensure the public pol-icy established in Section 22a-36 of the ConnecticutGeneral statutes is met. For more information, call the CTDEP Division of Inland Water Resources, (860) 424-3019.


In-Lake Management

3.1 The Appropriateness of In-Lake Management3.2 Managing Macrophytes3.3 Managing Algae

3.1 The Appropriateness of In-Lake ManagementIt is important to implement watershed management

measures to reduce inputs of nonpoint source pollutantsto lakes. Unfortunately, many Connecticut lakes havebeen on the receiving end of human-generated phospho-rus, nitrogen, sand, silt, and other nonpoint source pollu-tion for decades. As a consequence, cultural eutrophica-tion is commonplace throughout the state. Typicalsymptoms include: (1) increased growth of algae andmacrophytes; (2) increased growing space for macro-phytes due to sediment deposition; and (3) loss of dis-solved oxygen because the increased volume of organicmaterial, such as dead algae and macrophytes, has trig-gered an increase of the respiring bacteria population.Such lake conditions diminish commercial and recre-ational opportunities and reduce the value of shorelineproperties.

Communities facing in-lake eutrophication problemsgenerally incorporate a two-pronged managementapproach. First, they implement BMPs to reduce the flowof pollutants from the watershed into the lake. Second,they investigate and initiate activities designed to controlor manage the problem until the lake naturally adjusts tolowered pollution levels. It is important to recognize

In-Lake Management 35

that it is short-sighted for a community to focus atten-tion on attacking only the in-lake symptoms of water-shed pollution, such as algae blooms, weed beds, andsediment deposition. Long-term control of lake prob-lems requires that communities deal with their land-based pollution sources as well.

A healthy lake will support a healthy and diverse pop-ulation of algae and macrophytes. These plants are anintegral part of the ecosystem, providing fish and otherorganisms with habitat, food, spawning areas, and oxy-gen through photosynthesis. Management is necessaryonly when algae or weed growth becomes so extensivethat it interferes with the desired uses of a lake. In-lake management should never be designed to com-pletely eradicate algae or macrophyte populations; thegoal is to bring them back into balance with the nat-ural ecosystem and the desired uses.

3.2 Managing Macrophytes

Macrophytes are aquaticplants with roots, stems, andleaves that can be seen with-out the aid of a microscope.A survey of a typicalConnecticut lake will reveal many different macrophytespecies intermingling in the water and along the shore-

Duckweed, a free-flowingmacrophyte

waterweed


line. There is a great variety in size and shape — from theseven foot tall cattails growing on the shore, to quarterinch duckweed plants floating in a bay. A natural systemof checks and balances generally keeps any one speciesfrom dominating the ecosystem. This diversity is desir-able and a sign of a healthy lake.

Some Connecticut lake ecosystems, however, are domi-nated by one or two species of macrophytes. This is not abalanced ecosystem. The overgrowth of a single plant canimpair human use and enjoyment, especially if it forms athick weed bed. The macrophyte Eurasian watermilfoil is aprime example of this type of plant. Milfoil is not nativeto North America. It was brought from Europe and Asiaaround the turn of the century and first appeared in abun-dance in the Chesapeake Bay around 1920. Its unusualgrowth characteristics permit it to out compete its neigh-bors for growing space and light. Eurasian watermilfoiloverwinters as a standing plant, which gives it a head starton other plants at the beginning of the spring growingseason. Also, even a moderate size milfoil population willform a dense canopy on the water surface, effectivelyblocking out sunlight for other species of plants. Thesecharacteristics, in addition to its being capable of vegeta-tive reproduction, make Eurasian watermilfoil the numberone nuisance macrophyte problem in Connecticut lakes.

Other species of macrophytes can also overpopulateand cause problems. These include curlyleaf pondweed,water lilies, cattails, purple loosestrife, and duckweed.Control techniques vary according to the species of plantand where it grows. Some macrophytes are free-floatingand do not sink roots into the lake bottom. Duckweed, forexample, is a tiny free-floater that reproduces rapidly andcan cover the water surface of a small lake or bay. Cattailsand water lilies are examples of emergent plants that haveroots in the lake bottom and leaves extending into the air


or floating on the surface. Submergent macrophytes, incontrast, have roots in the sediments but grow entirelyunderwater, although several have flowers that extend outof the water during part of the season. Selecting the besttechnique for managing macrophytes in your lake isimportant. Contact the CT DEP Lakes ManagementProgram, (860) 424-3716, for information.

The following management techniques are discussedin this section:

• Mechanical removal of plants• Lake bottom barriers• Sediment removal• Grass carp• Aquatic herbicides• Light limiting dyes• Wintertime drawdown• Weevil predation

Eurasian watermilfoil and leafy pondweed.


Mechanical removal of plantsThere are three mechanical means of physically

removing rooted macrophytes from a lake: cutting, rak-ing, and uprooting. The following is a discussion of thesetechniques.

CuttingCutting is done to macrophyte stems. For small under-

water areas, such as swimming beaches or around a dock,one might choose to use a hand held underwater cutter.

There are several types and themost common has a V-shapedcutter blade. The cutter isthrown into the water and asit is reeled back in, the bladecuts the macrophyte stems.Manufactures have also devel-oped battery powered cuttersthat use a scissor-action to clipunderwater stems. For emer-gent macrophytes on or nearthe shore, garden-variety weedwhips and scythes are oftenused.

For larger lake areas, a spe-cialized cutting machinemounted on the deck of afloating barge is frequentlyemployed. The machine has arow of reciprocating sickle

blades that are lowered to a desired depth. These cuttersmow aquatic vegetation down as the barge moves throughweed beds. Mechanical weed harvesters are similar to themechanical cutters, except they have a conveyor systemthat loads the plants onto the barge after cutting. When

Pickerelweed


the storage area is full, the harvester off-loads the materialonto a separate shuttle barge or travels to the shore.

RakingRaking is typically used to clear weeds from small shal-

low lake areas, such as swimming areas and beaches.Implements vary from ordinary garden rakes to toolsspecifically designed to gather water weeds. Raking isoften done to clean up specific shore areas after cuttingoperations. It is labor intensive and generally not appro-priate for large areas.

UprootingAnother mechanical method of macrophyte removal is

uprooting where the plant is removed roots and all. Mostaquatic plants, especially the nuisance species, are veryhardy. Simply cutting these plants has the same effect asmowing the grass on a lawn, it will grow back. Uprootinghas longer-term effects because individual plants areremoved from the lake. An intensive uprooting programwill result in a weed-free area until new plants move in

Watershield and white waterlily,emergent macrophytes


and begin growing.There are many ways to uproot macrophytes. The

method chosen is generally dictated by how strongly theplant roots in the sediments. Many of aquatic plants,such as bushy pondweed, commonly referred to as naiadspecies, are rooted very weakly. They can be pulled up byhand with little effort.Other species, such asEurasian watermilfoil, aremore strongly rooted. Theirstems usually break off ifone tries to pull up theroots by hand, leaving theroots intact. Still otherspecies, such as cattails,purple loosestrife, andwater lilies, have extensiveroot systems and are practi-cally impossible to pull upby hand.

In these latter cases, theuprooting approach tomacrophyte removalrequires the use of tools.The imagination is often the limit. Macrophytes on theshore have been uprooted using various means, such aschains and cables. Dragging tools are often used foruprooting submergent plants. Dragging the bottom hasproven especially effective after a harvesting operationhas removed most of the stems and leaves. Lake groupshave also used chain link fence, rebars, and old bed-springs for this purpose.

A hydrorake is a motorized weed remover mounted ona barge similar to a weed harvester. Instead of the har-vester-type cutting bar, a hydrorake has a forked imple-

Watermilfoil


ment that digs into the sediment and lifts out macro-phytes, roots and all. If uprooting is used, the hydrorakeis usually the most convenient tool, especially if a largearea needs clearing or shoreline access presents a problemfor pulling or dragging equipment.

Collection and disposal of the aquatic vegetationthat has been cut, raked, or uprooted is a very impor-

tant part of amechanical macro-phyte removal pro-gram. Many nuisancespecies, including Eura-sian watermilfoil, repro-duce vegetatively. Thismeans that fragmentsleft in the lake can growback into new full-sizedplants. For this reason itis important to collect asmuch of the plant mate-rial as possible after aharvesting operationand remove it from the

water. Some macrophytes, including Eurasian watermil-foil, are very buoyant immediately after cutting and floatright to the surface. Surface containment booms can beused to catch drifting material. Other plants, such asnaiads and other pondweeds, do not float after cutting.For these plants, weighted seine nets can be used to trapmaterial drifting in the water column and haul it toshore. It is important, however, to use nets with a meshwidth large enough so that fish are not trapped.

The preceding paragraphs describe how rooted macro-phytes are cut, raked, and harvested. Unrooted, free-float-ing plants present a special challenge for mechanical

Cattails


removal. The free-floating macrophyte species that causemost problems are duckweed and watermeal. These tinyplants reproduce very rapidly and, under ideal conditions,can cover an entire bay or pond in a matter of weeks.Being free-floating, they can be blown by the wind andoften accumulate in great numbers in bays or on beaches.Duckweed can be collected using homemade screeningdevices. Once corralled and pushed to shore, the plantscan then be heaped into containers and hauled away.

All species of macrophyte that have been mechanicallyremoved from a lake must be transported away from thelake. As discussed in Chapter 2, dead vegetation is rich inorganic matter. If harvested plants are allowed to decaynear the shore, nutrients from them will enter the lakeand fertilize aquatic growth. The best course of action isto create compost sites at a distance from the lake andrecycle the compost as soil conditioner and land-basedfertilizer.

Legal requirements on mechanical removal of plantsBefore initiating any plan for mechanical removal of

plants, contact the local inland wetlands commission todetermine if a local permit is required.

Lake bottom barriersBenthic weed barriers are sheets of fiberglass mesh

screening or perforated black nylon that cover the bot-tom of a lake. Barriers kill rooted plants by physicallyrestricting their growth up from the sediments. They alsoblock sunlight from reaching plants. Barriers are mosteffectively installed early in the growing season. In latespring or summer it is difficult to lay the barriers flat onthe bottom because strong stands of vegetation propthem up.

The cost of materials and labor of benthic weed barri-


ers, especially if scuba divers are used, usually restrictstheir use to areas of high activity, such as boat launches,swimming areas, and boat lanes. They must be fullysecured to the bottom at all times. Stakes and weightedanchors are typically used, but whatever the method, thebarriers should be inspected regularly. If the barriersbecome detached from the bottom, they can present adangerous situation.

Over time, sand and silt will settle on benthic barriers,especially if a barrier is near a storm drain outlet thatdirects sediment-laden water toward the barrier. Even alight coating of sediment on top of bottom barriers willallow new macrophytes to establish themselves, render-ing the barrier useless. Barriers should be removed at theend of each summer, cleaned, and stored for reinstalla-tion in the spring.

Sediment removalThe input of sediments from the watershed can result

in increased macrophyte growth by making the lake shal-lower, thereby increasing growing space for rooted plants.Also, watershed sediments, especially from developedland, carry nutrients and organic wastes that fertilize thenew growth. For these reasons, it is important to preventsediment from moving into a lake.

In lakes where sedimentation has taken place fordecades and nuisance macrophytes grow, sedimentremoval is often used with watershed BMPs designed toprevent sediments from getting into the lake. There aretwo basic approaches to sediment removal. The first is todrawdown the lake, let the bottom dry out, and excavatethe sediments using conventional equipment, such asloaders and backhoes, customized as needed for workingin soft sediments. The second option is to keep the waterin the lake and conduct a hydraulic dredging operation


from the surface. Both methods reduce weed habitat byincreasing water depth and removing nutrient-rich sedi-ments, as well as removing the problem macrophyte.

The first option, drawdown and excavation, requiresprofessionally designed drawdown and refilling plans.Outlet pipe and control structures must be maintained ingood working order. If these structures are not present,alternative methods of drawdown include pumping andsiphoning. The impact on area wells, fish, and otheraquatic life must also be considered before the drawdown.Drawdowns greatly affect the community of aquaticinsects living on the lake bottom in the exposed areas.These creatures are an important link in the food chainand less mobile species are likely to perish.

Drawdown can also cause shoreline slumping,increased beach erosion, and damage retaining wallswhen sediments consolidate or wave action erosionoccurs at the lower water level. The growth of somespecies of macrophytes is actually enhanced by draw-down. All of these potential impacts must be carefullyweighed against the benefits of sediment removal.However, when properly employed, excavation has beenfound to be a cost-efficient and effective macrophyte con-trol method.

For lakes where drawdown and excavation is not feasi-ble, the alternative for sediment removal is hydraulicdredging. A hydraulic dredge is a specialized barge with along pipe that extends to the bottom of the lake. Rotatingblades break up the sediments at the end of the pipe, andthe resultant slurry, is pumped up to the surface. The slur-ry is then sent through a pipeline into a series of contain-ment basins. The sediment settles out as the slurry drainsthrough the basin system. In the last basin the water isusually treated with a chemical flocculent or coagulant toremove the remainder of the sediment before discharge


back to the lake.An extensive feasibility study must be completed by a

qualified engineering/environmental firm before under-taking a hydraulic dredging project. Capital outlays arehigh and include either the purchasing or leasing of adredge and related equipment or the contracting fordredging and engineering services, as well as the acquisi-tion of property rights and construction permits for thebasins. Proper disposal of the removed sediments is animportant concern for both excavation and dredgingoperations. Locating and acquiring a dewatering site isalso a significant part of the feasibility study. If sedimentsare not contaminated by toxic pollutants, such as heavymetals or hydrocarbons, dredge spoils may be used for asa soil conditioner or landfill cover.

Legal requirements on sediment removalPermits that may be required include:

• a water pollution discharge permit from the CT DEPBureau of Water Management, Permitting,Enforcement and Remediation Division

• Army Corps of Engineer 404 permit• Army Corps of Engineer 401 permit• local inland wetlands permits• reviews by various CT DEP divisions

Grass carpNatural growth regulation of nuisance macrophyte

species through food chain interactions and competitionamong species is desirable. In this spirit, some managersin North America have been promoting a species of fishknown as the grass carp, or white amur, as a naturalmethod of macrophyte management. These fish are vege-tarians and eat standing crops of certain species of plants.In Connecticut, private pond owners can apply to the


state for a permit to use grass carp to control aquaticweeds. Since long-term impacts on the environment areunknown, only the sterile variety, referred to as triploidcarp, are legal.

There are some inherent problems with stocking grasscarp in a lake. The grass carp is Asian and not native toNorth America; therefore, there is no natural system ofchecks and balances to control grass carp. Potentially, itcould dominate the ecosystem. Lake groups must decidehow many and what size fish to stock. Stocking too manyfish may eventually strip the lake of macrophytes whilestocking too few may not provide the reduction inmacrophytes desired. Also troubling is the fact that thefish prefer some plants to others. Eurasian watermilfoil,for example, is not one of their favorites. Grass carpmight eat other plants in the lake before going after thetarget nuisance macrophyte.Grass carp also tend to accelerate the recycling of nutri-ents in the lake. They eat up to two to three times theirbody weight per day, returning most to the water as wastematerial. This waste material can function like a fertilizerand trigger increased algae growth. Grass carp can alsoincrease water turbidity as they routinely stir up bottomsediments in their constant search for food. This actionreduces sunlight in the water column and impacts thehabitat and metabolic functions of native fish, insectsand other organisms in the lake.

For these and other ecological reasons, the CT DEPLakes Management Program does not advocate grass carpfor control of aquatic weeds. However, Connecticutallows importation of sterile grass carp for private pondsand lakes through a permit program administered by theCT DEP. For further information, contact the CT DEP,Division of Fisheries, (860) 424-3474.


Legal requirements on grass carpPermit conditions require:

• inspection and recommendation by a CT DEP tech-nical assistance fisheries biologist

• written permission of all property owners• screened inlet and outlet

Aquatic herbicidesHerbicides are sometimes used to kill nuisance macro-

phytes in specific lake areas. In Connecticut, herbicidescan be applied only through a permit process adminis-tered by the CT DEP, Bureau of Waste Management,Pesticide Management Division. There are three types ofherbicides in general use: contact, systemic, and heavymetal. A contact herbicide destroys plant cells at thepoint where the poison makes contact, thereby weaken-ing the plant until it eventually dies. A systemic herbicideis absorbed at the point of contact and then spreadsthroughout the plant and interferes with the metabolicsystem, such as its ability to photosynthesize or to repro-duce cells. Systemics can kill the roots as well as the topsof plants. A metallic herbicide employs a metal thatmigrates throughout the plant and interferes with one ormore of the plant’s critical metabolic processes. Coppercompounds are the only metallic aquatic herbicide.

• In general, the use of herbicides is not recommend-ed and is not eligible for funding under the CT DEPgrant program for recreational lakes. The primaryreason is that herbicide control is short-term in itseffect. The nuisance macrophyte may grow backand additional applications are usually necessary.Herbicides, unlike harvesting, may have unknownconsequences, such as the long-term impacts of thechemical applications on nontargeted species ofplants and animals. Thus, lake groups often choose


a more conservative approach, especially if there isa lot of swimming in the lake.

If an herbicide is used in a small lake, the associateddecomposition of large amounts of dead macrophytescould tax the dissolved oxygen supply. The decayingplant matter also increasesthe amount of muck on thelake bottom, which impactsfish spawning sites andaquatic insect habitat. Theseconsiderations must beunderstood before herbi-cides are used for macro-phyte control.

Legal requirements on aquatic herbicidesState regulations require a permit for every chemical

treatment. All pesticide-related issues are the responsibili-ty of the CT DEP Bureau of Waste Management, PesticideManagement Division. Permits are reviewed with respectto the nature of the vegetation condition, the proposedchemical and dosage, application procedures, and poten-tial adverse effects on water uses. The permit applicationincludes the following:

• review by the CT DEP Bureau of WasteManagement, Pesticide Management Division,Division of Fisheries, and other DEP divisions

• a review and comments from the local inland wet-lands commission

• submission of a vegetation control plan• and, if your lake is in the watershed of a public

drinking water supply waterbody, a review by thelocal water utility and the State of ConnecticutDepartment of Health Services.


Additional information on aquatic herbicidesMore information can be obtained in “Control of

Aquatic Weeds and Algae,” available from the CT DEP,Bureau of Waste Management, Division of PesticideManagement, (860) 424-3369.

Light limiting dyesSubmergent macrophytes need clear water so that sun-

light can reach their leaves. They cannot thrive in waterswhere photosynthesis is inhibited. This concept has leadto the marketing of dyes that color water so that lightwaves are blocked at or near the water surface. These dyeshave been used primarily in small water bodies. To beeffective, the lake or pond must have little or no inflowor outflow of water. Water movement in and out of thewaterbody will dilute the dye and quickly lessen its effec-tiveness. Furthermore, Connecticut, due to the potentialdownstream impacts with discoloration and reduced aes-thetic value, the use of water dyes is restricted to lakeswithout outlet streams.

The use of water dyes is most appropriate in special sit-uations, such as ornamental ponds. The majority of lakesin Connecticut have inlets and outlets, which inhibits theuse of dyes. The use of dyes artificially controls submer-gent vegetation. A healthy, natural ecosystem cannot beestablished if light is not allowed to penetrate the watercolumn.

Legal requirements on light limiting dyesAll applications of light limiting dyes must be permit-

ted by CT DEP Bureau of Waste Management, Division ofPesticide Management.


Wintertime drawdownWinter drawdown of lakes and ponds exposes sedi-

ments and macrophytes to freezing temperatures. Thistechnique has been proven very effective in killingEurasian watermilfoil beds when circumstances are right.The kill is most complete, for example, when the freezeoccurs after the sediments have had a chance to dry.

The primary advantage of winter drawdown is the rela-tively low cost compared to other weed control options.A primary disadvantage of winter drawdown is that thecontrol and effect is limited to the area exposed. To initi-ate a winter drawdown, several aspects of the processshould be considered. First, the water level of the lakemust be lowered; if the spillway does not have this capa-bility, the lake must be pumped or siphoned. If shorelineresidents utilize on-site wells, the effect to the water tablemust be investigated prior to drawdown. Releases of watermust also be controlled to prevent downstream flooding.Refill must both maintain downstream flows and achievethe normal summer lake level before the beginning of thegrowing season, which is approximately April 15 inConnecticut. If a lake is lower than normal during thegrowing season, areas previously too deep for weedgrowth may subsequently develop infestations of weeds.

In addition, there may be adverse biological effectsfrom a winter drawdown. The area along the shoreexposed to freezing is the most biologically productiveand diverse of the lake. Winter exposure will kill manydesirable native plants and allow more problematic exoticplants to become established. Unless nuisance weedsbecome intolerable, winter drawdown should be avoided.

Legal requirements on winter drawdownBefore initiating drawdown, the following should con-

tact the CT DEP Bureau of Water Management, Division ofInland Water Resources and your local inlands wetland


commissions to determine whether drawdown is regulated.

Weevil predationSome lakes in Connecticut have experienced a reduc-

tion in Eurasian water milfoil. These cyclical declines areusually found in lakes that have not been extensivelymanaged for water milfoil. It is suspected that herbivo-rous aquatic weevils and caterpillars may be responsiblefor the reduction. It is also suspected that water milfoilcontrol programs such as winter drawdown, harvesting,and herbicide applications may have an adverse impacton these beneficial organisms. Therefore, until the resultsof research on these organisms are available, and a deter-mination has been made on cyclical reduction of watermilfoil in a given lake, it may be to the advantage todelay water milfoil control programs.

This approach is recommended only for lakes withestablished populations of Eurasian water milfoil; anyinstances of new infestations should be reported to theCT DEP to determine the most appropriate managementmethod.

Additional information on weevil predationFor additional information on weevil predation, con-

tact the CT DEP Bureau of Water Management, LakesManagement Program, (860) 424-3716.


3.3 Controlling AlgaeAlgae are plants that contain chlorophyll but do not

have true roots, stems, or leaves. Some species exist asmicroscopic single cells. Other species grow in massaggregates of cells, termed colonies, or in strands, termedfilaments. Some algal species even resemble macrophytegrowing on the lake bottoms.

Algae are a natural component of the aquatic ecosystemand all lakes in Connecticut contain some algae. As withmacrophytes, problems generally occur when one or twospecies grow out of control. When this happens, it istermed an algae bloom. Blooms can give water an unpleas-ant taste or odor, reduce water clarity, and color the lake avivid green, brown, yellow, or even red, depending on thespecies. Filamentous and colonial algae are especially trou-blesome because they form scums or mats on the lake sur-face. These mats can drift and clog water intakes, foulbeaches, and ruin recreational opportunities.

Unlike rooted macrophytes that rely on the sedimentsas their source of nutrients, algae generally receive theirnutrient supply from the water. When nutrients in thewater column are plentiful, there is a good chance that analgal bloom will occur. Three common nuisance speciesfound in Connecticut lakes are all in the blue-green algaefamily: Anabaena, Aphanizomenon and Microcystis. Beforean algae control method is used, the algae should be iden-tified by someone familiar with species classification.

Techniques to control algae fall into two basic cate-gories: methods that reduce the availability of essentialnutrients in the water and methods that kill or directlyremove algae from the lake. These techniques are dis-cussed in the next sections.

Reducing phosphorus availabilityPhosphorus is one of several essential nutrients that


algae need for growth and reproduction. In most naturallakes phosphorus is in short supply and serves as the lim-iting factor for algae growth. Lakes in developed water-sheds, however, receive unusually generous amounts ofphosphorus through such sources as stormwater runoffand septic systems. Phosphorus may also enter a lakefrom its sediments when, under certain conditions, it isreleased to the water column.

To reduce the availability of phosphorus, lake manage-ment specialists can do two things: strip it out of thewater column and/or seal the bottom sediments so thatphosphorus is not allowed to move into the water col-umn. In the first process, a chemical agent is added to thelake water to combine with phosphorus forming a flocthat settles to the lake bottom. The second process is pri-

A variety of algae types, enlarged


marily accomplished by keeping the bottom waters oxy-genated. When oxygen is present, phosphorus chemicallycombines with other elements, primarily iron, and isessentially locked in the bottom sediments. The absenceof oxygen results in the breakdown of chemical bonds,which frees the phosphorus from the sediments. Thisallows the phosphorus to move into the hypolimnion.Anytime the bottom waters are churned to the lightedsurface water, its load of phosphorus becomes available toalgae. This phenomenon often occurs during spring andfall overturn; strong storms can also cause the circulationof phosphorus-rich bottom waters to the surface. The fol-lowing discusses four specific techniques for reducing theavailability of phosphorus.

Buffered alumBuffered alum is a mixture of aluminum sulfate and

calcium compounds. This compound is applied to thewater surface, usually from a boat criss-crossing the lake.Heavier than water, alum forms a precipitate glob thatsoaks up phosphorus as it sinks to the bottom. On thebottom, it continues to capture and hold phosphorus. Inthis manner, phosphorus is essentially stripped from thewater column and without this essential nutrient algaecannot grow.

An analysis of a lake and application methods isrequired to determine whether alum treatments will besuccessful and environmentally sound. If inflowingwaters carry a significant supply of phosphorus, the effectof an alum application will be short-lived. Therefore, it isimportant that watershed management measures areimplemented in conjunction with alum control to reducephosphorus pollution and its effects.


Legal requirements for alum applicationsApplications of alum is regulated by CT DEP Bureau of

Waste Management, Pesticide Program. For more infor-mation on permit requirements call the PesticideProgram, (860) 424-3369.

Hypolimnetic aerationHypolimnetic aeration refers to a process that intro-

duces oxygen-rich water into the bottom waters withoutdisturbing the natural stratification of the lake. As dis-cussed above, oxygen in the bottom waters effectivelyseals phosphorus in the sediments. Maintaining stratifica-tion is especially important in lakes that support a “two-story fishery”; that is, a lake that has warm water fish(e.g., bass and pan fish) living in the epilimnion and coolwater fish (e.g., trout or walleye) living in thehypolimnion.

Hypolimnetic aeration is accomplished using a special-ly designed, self-contained, underwater cylinder com-posed of inside and outside chambers, both open at thebottom. Air is pumped to the bottom of the inside cham-ber. The rising air bubbles carry the bottom water to thetop of the cylinder where it is aerated. The newly oxy-genated water then is cycled down the outside chamberand released at the lake bottom.

It is essential to perform a feasibility study of the phys-ical and chemical characteristics of a lake to determinewhether hypolimnetic aeration will control phosphorusreleases from the sediments as well as to determine thesize and type of equipment needed.

Hypolimnetic withdrawalHypolimnetic withdrawal reduces the amount of phos-

phorus in the hypolimnion by pumping the phosphorus-rich bottom water out of the lake into an outlet stream. A


project feasibility study must be conducted to determinethe amount of phosphorus cycling in and out of the lake.Since hypolimnetic water can also contain iron, sulfides,and other constituents that degrade the water quality ofreceiving streams, the water must be treated by aerationprior to discharging. The study must also examine otherpossible adverse effects on streams receiving the low oxy-gen/high phosphorus water.

Legal requirement on hypolimnetic withdrawal dischargeThe Permits, Enforcement and Remediation Division of

the CT DEP Bureau of Water Management requires awater pollution discharge permit for hypolimnetic with-drawal discharges, (860) 424-3705.

Artificial circulationArtificial circulation, also known as conventional aera-

tion, can be accomplished by introducing air bubbles atthe bottom of the lake. The rising air bubbles then carrythe oxygen-poor bottom waters to the surface. Artificialcirculation can also be accomplished in shallow lakes byphysically mixing the water with a fountain or surfaceaerator. This method ensures that all the water will atsome time be displaced to the lake surface where oxygenis transferred to the water from the atmosphere. Thesemethods discourage the growth of certain types of blue-green algae that do not grow well in moving water.

While the benefits of having oxygen throughout thewater column may be great (e.g., sealing phosphorus inthe sediments ), there are tradeoffs. For example, artificialcirculation breaks down natural stratification. All of thewater will, therefore, be circulating as in a swimmingpool, maintaining uniform temperature and oxygen lev-els from top to bottom. So, the potential for a two-storyfishery is lost. Additionally, artificial circulation may


allow phosphorus rich water from the bottom of the laketo move to the surface where sunlight is available creat-ing ideal conditions for algae blooms.

As with hypolimnetic aeration and withdrawal, adetailed diagnostic feasibility study for artificial circula-tion proposals is needed. Poor design or installation thatdoes not destratify the lake, may not improve water quali-ty and could increase algal growth.

Killing or directly removing algaeAlgae may be killed with an algicide or directly

removed in a variety of ways. The following is a descrip-tion of both approaches to controlling algae.

Aquatic algicidesCopper-based compounds, such as copper sulfate, are

typically used as algicides. These compounds inhibit pho-tosynthesis, which eventually kills plant cells. They canbe applied in either liquid or granular form. InConnecticut, however, only a limited number of algicidesare approved for use.

Legal requirements on aquatic algicidesLegal requirements for algicides are the same as the

legal requirements for herbicides discussed in section3.25.

Additional information on aquatic algicides“Control of Aquatic Weeds and Algae” may be

obtained from the CT DEP Bureau of Waste Management,Division of Pesticide Management, (860) 424-3369.


Mechanical removalMany species of filamentous algae float on the surface

in unsightly mats. Each mat is composed of millions oftiny interwoven filaments. Techniques described in the“Managing Macrophytes” section and the section on“Mechanical removal of plants” earlier in this chapter,and the removal of duckweed and clippings from harvest-ed weed beds can also be employed to collect and removefloating filamentous algae. Modified fish seines are typi-cally used to corral algae mats. After the mats are pushedto shore, they can be heaped into containers and hauledaway.


CONCLUSION

This booklet provides your lake organization with theresources to improve and maintain the water quality ofyour lake. Although this guide will not train the lakesideproperty owner to be a lake manager or limnologist, it willgive lake users a general understanding of lake scienceand an overview of the principals and techniques of man-aging these unique and valuable resources. The CT DEPlakes management staff looks forward to providing tech-nical assistance and acting as a liaison between yourgroup and other government agencies. If you have anyconcerns about questions concerning lake water quality,please contact us at (860) 424-3716.

In addition to the distribution of this guide, our staffcan provide the following:

• in-lake algae and weed control techniques• watershed management guidelines• general information on algae and weed control• general water quality data on a large number of

Connecticut lakes• technical assistance and review of proposed plans

for lake projects• environmental review team reports• information on state and federal financial assistance

programs for algae and weed control activities• information on lake management services provided

by consultants and contractors• enforcement related to environmental concerns

related to lake water quality

60

Appendix A:Technical Glossary

acidification: The process in which acid deposition oracid runoff from the watershed causes an increase in acid-ity and lowers the pH (measure of hydrogen) of a water-body.

atmospheric diffusion: The process of atmospheric oxy-gen moving into or out of a body of water in order toreach equilibrium.

best management practice (BMP): A practice, procedure,structure, or combinations thereof, that is planned andimplemented to prevent, minimize or control point ornonpoint source pollution of ground or surface water.

chlorophyll-a: A pigment associated with photosynthesisthat serves as an index of algal productivity.

clarity: The distance one can see into water. Transparencyis measured with a white and black disk called a secchidisk.

criteria: Elements of Connecticut’s Water QualityStandards, expressed in parameters and their constituentconcentrations and levels, or in narrative statements, rep-resenting a quality of water that supports a particular des-ignated use.

Appendix A 61

cultural eutrophication: See eutrophication.

designated use: Those uses specified in Connecticut’sWater Quality Standards for each surface watercourse orgroundwater area.

dissolved nutrients: Nutrients, which include any chem-ical element, ion, or compound required by an organismfor the continuation of growth, reproduction, and otherlife processes, found in solution in water and readilyavailable to aquatic organisms.

dissolved oxygen: The oxygen found in solution in waterand readily available to aquatic organisms. It is usuallyexpressed in milligrams per liter or as the percent of satu-ration.

ecology: The study of organisms and their relationship tothe environment.

ecosystem: A system where organisms and their environ-ment are interdependent on one another.

epilimnion: The warm surface layer of a lake during sum-mer stratification.

erosion: Movement of soil from its place of origin bywind or water.

eutrophic: A lake or pond that is rich in plant nutrientsusually having extensive rooted plant and algae growth.

eutrophication: Increased aquatic plant growth and theassociated physical, chemical, and biological changes in awaterbody due to nutrient and organic matter enrichment,

and sedimentation. If the process is accelerated by man-made influences, it is termed “cultural eutrophication”.

heavy metals: Lead, copper, cadmium, zinc, nickel, andchromium examples of heavy metals naturally occur inthe environment; high levels come from marinas, auto-mobiles, industrial waste and polluted atmosphere.Deposition in a lake can prove toxic to aquatic species.

hydrocarbons: The primary component of motor fuelsand engine oil.

hypolimnion: The coldest bottom layer of a lake duringsummer stratification. This layer is often void of dissolvedoxygen.

internal nutrient loading: The process of nutrients beingreleased within a lake through its sediments.

lake manager: One involved with administering andconducting activities related to lake water quality, recre-ation, fisheries, and other concerns related to maintain-ing and improving lake resources.

limiting nutrient: The nutrient that is least available rel-ative to the growth needs of an organism. In freshwatersystems, phosphorus or nitrogen may be the limitingnutrient for plant growth.

limnology: The scientific study of lakes and ponds.

limnologist: A scientist who studies lakes and ponds.

macrophytes: Aquatic plants with roots.


Appendix A 63

mesotrophic: the condition of lakes or ponds being onlymoderately rich in plant nutrients

metalimnion or thermocline: The layer of rapid temper-ature and density change during summer stratification,often referred to as the thermocline, situated between theepilimnion and hypolimnion in a stratified lake.

nonpoint source pollution: Entry of effluent into groundor surface water in a diffuse manner where the source isnot readily discernible, e.g., soil erosion, stormwater, orrunoff from poorly managed land use activities.

nutrient: A chemical element required for life processes.In lakes, phosphorus and nitrogen are the two nutrientsof primary concern.

oligotrophic: A lake or pond with little nutrients andsediments, low in plant productivity, and high trans-parency.

organic matter: Material of plant or animal origin.

pathogen/pathogenic bacteria: A microorganism capableof causing a disease.

pesticide: A chemical agent that kills plant or animalpests. Aquatic herbicides and algicides are all categorizedas pesticides.

photosynthesis: The process of plants using light energyto convert inorganic substances into organic material.Oxygen is a by-product of this process.

point source pollution: Pollution discharged from a dis-

cernable source with a definite point of entry into groundor surface water.

sediment: The soils of the bottom of a waterbody.,

sedimentation: The process of soil and organic materialsbeing transported from their sites of origin and becomingsuspended in the water column or accumulating on thebottom of a waterbody. Sedimentation causes reducedclarity, increased nutrient loading, and decreased waterdepth.

stratification: The condition that results when thewarmer surface of a lake lays above colder bottom waters.

thermocline: See metalimnion.

trophic classification: The classification of the biologicalproductivity of a lake, as measured by the nutrient con-centrations, water clarity, and other parameters. Thetrophic categories are oligotrophic, early mesotrophic,mesotrophic, late mesotrophic, eutrophic, and highlyeutrophic.

water quality: The physical, chemical and biologicalcharacteristics of surface or ground waters.

water quality classifications: A classification systemestablishing the designated uses of surface and groundwaters and the criteria necessary to support those uses.

watershed, or drainage basin: The drainage area whereall land and water drains or flows toward a central collec-tor such as a stream, river, or lake at a lower elevation.

64 Caring For Our Lakes

65

Appendix B:County Agricultural Centers

Fairfield County NRCS, S&WCDUCONN Agricultural Center67 Stony Hill RoadBethel, CT 06801(203)774-6108

Hartford County NRCS, S&WCDAgricultural Center627 River RoadWindsor, CT 06095(860)688-7725

Litchfield County NRCD, S&WCD1185 New Litchfield StreetTorrington, CT 06790(860)626-8258

Middlesex County NRCD, S&WCDUCONN Extension CenterP.O. Box 70Haddam, CT 06438(860)345-3219

New Haven County NRCD, S&WCDUCONN Extension Service900 Northrop RoadWallingford, CT 06492(203)269-7509

New London County NRCD, S&WCDUCONN Extension Service 238 West Town StreetNorwich, CT 06360(860)887-3604

Windham County, NRCD, S&WCDUCONN Extension CenterP.O. Box 112139 Wolf Den RoadBrooklyn, CT 06234(860)774-9600 or (860)774-0224

Tolland County NRCD, S&WCDUCONN Agricultural Center24 Hyde AvenueVernon, CT 06066(860)875-3881

66 Caring For Our Lakes

67

Appendix C: Summary of the TrophicClassifications of Connecticut Lakes

Lake Town(s) Surface Area(Acres)

Oligotrophic

Bashan East Haddam 276.3Beach Pond Voluntown 394.3Billings North Stonington 105.1Mashapaug Lake Union 297.1Riga Lake Salisbury 169.5Uncas Lake Lyme 69.0West Hill Pond New Hartford 238.0

Early Mesotrophic

Bigelow Pond Union 18.5Candlewood Lake New Fairfield, Sherman, 5420.0

New Milford, Danbury & BrookfieldColumbia Lake Columbia 277.2Coventry Lake Coventry 378.0Cream Hill Pond Cornwall 72.0Dodge Pond East Lyme 33.0East Twin Lake Salisbury 562.3Higganum Reservoir Haddam 32.0Killingly Pond Killingly 137.5Mohawk Pond Goshen 15.2Mt. Tom Pond Litchfield, Morris, & 31.5

WashingtonNorwich Pond Lyme 27.5Pachaug Pond Griswold 830.9Pattaconk Pond Chester 55.5Rogers Lake Lyme & Old Lyme 264.9



S. Spectacle Lake Kent 93.0Wauregan Reservoir Killingly 68.0Lake Winchester Winchester 229.0Wyassup Lake North Stonington 92.4

Mesotrophic

Lake Alexander Killingly 190.4Anderson’s Pond North Stonington 54.3Ball Pond New Fairfield 89.9Black Pond Woodstock 73.4Lower Bolton Lake Bolton & Vernon 178.4Burr Pond Torrington 85.6Cedar Lake Chester 68.0Crystal Lake Ellington & Stafford 200.9Gardner Lake Salem, Montville & Bozrah 486.8Glasgo Pond Griswold 184.2Gorton’s Pond East Lyme 53.0Green Falls Reservoir Voluntown 46.9Halls Pond Ashford & Eastford 82.3Hatch Pond Kent 61.0Highland Lake Winchester 444.0Little (Schoolhouse) Thompson 65.4Morey Pond Ashford & Union 40.0Park Pond Winchester 76.7Pataganset Lake East Lyme 123.0Lake Pocotopaug East Hampton 511.7Powers Lake East Lyme 152.6Quaddick Reservoir Thompson 466.8Lake Quassapaug Middlebury 271.0Quonnipaug Lake Guilford 111.6Shenipsit Lake Vernon, Ellington & Tolland 522.8Terramuggus Lake Marlborough 83.0Tyler Lake Goshen 182.0West Side Pond Goshen 42.4

Appendix C 69


Lake Wononscopomuc Salisbury 352.6Wrights Pond Westbrook, Essex & Deep River 37.0

Late Mesotrophic

Beseck Lake Middlefield 119.6Black Pond Meriden & Middlefield 75.6Middle Bolton Pond Vernon 114.9Fitchville Pond Bozrah 71.1Lake Hayward East Haddam 198.9Hitchcock Lake Wolcott 118.4Long Pond Ledyard & North Stonington 98.6Mamanasco Lake Ridgefield 95.0Moodus Reservoir East Haddam 451.0Mudge Pond Sharon 201.0Squantz Pond New Fairfield & Sherman 288.0Taunton Pond Newtown 126.0Lake Waramaug Warren, Washington & Kent 680.2

Eutrophic

Amos Lake Preston 105.1Aspinook Pond Lisbon & Canterbury 333.3Avery Pond Preston 50.6Bantam Lake Litchfield & Morris 916.0Batterson Park Pond Farmington & New Britain 162.7Crystal Lake Middletown 65.5Dog Pond Goshen 71.3Eagleville Lake Mansfield 80.0Lake Housatonic Shelton 328.2Howell Pond Hartland 17.3Lake Kenosia Danbury 56.0Leonard Pond Kent 15.0Lake Lillinonah Southbury, Bridgewater, 1900.0

Brookfield & NewtownLinsley Pond North Branford & Branford 23.3



Long Meadow Pond Bethlehem 11.7Moosup Pond Plainfield 97.2Rainbow Reservoir Windsor 235.0Red Cedar Lake Lebanon 141.0Roseland Lake Woodstock 88.0Lake Wononpakook Salisbury 164.0Lake Zoar Newtown, Monroe, 975.0

Oxford & South

Highly Eutrophic

Dooley Pond Middletown 28.0Hanover Pond Meriden 73.0Holbrook Pond Hebron 72.5Hopeville Pond Griswold 149.4North Farms Reservoir Wallingford 62.5Pickerel Lake Colchester 88.6Silver Lake Berlin & Meriden 151.0West Thompson Lake Thompson 195.0Lake Winnemaug Watertown 120.0Wood Creek Pond Norfolk 151.01860 Reservoir Wethersfield 35.0

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