Lake Water Quality Glossary
Plain-language definitions for 163 lake water quality terms used in LakeQuality report cards. From Secchi depth to trophic state index, understand what the numbers mean for your lake.
Water Quality
Dissolved Oxygen
The amount of oxygen gas dissolved in lake water, measured in milligrams per liter, essential for fish survival and a key indicator of lake health.
Internal Phosphorus Loading
The release of phosphorus stored in lake-bottom sediments back into the water column, often triggered by low oxygen conditions in deep water.
Lake Grade
An A-through-F letter grade assigned by LakeQuality for nutrients and algae against EPA National Lakes Assessment ecoregion condition classes. Water clarity is shown but not scored. Lakes without enough evidence are UNRATED, not given an F.
Phosphorus
A nutrient that fuels algae growth in lakes, measured as total phosphorus in micrograms per liter.
Water Clarity
The transparency of lake water, typically measured by Secchi depth, a primary indicator of water quality and recreational suitability.
Measurement
Chlorophyll-a
A green pigment found in all photosynthetic organisms, used as a direct measure of algae concentration in lake water.
Secchi Depth
A measurement of water clarity determined by lowering a black-and-white disk into the water until it disappears from view.
Total Suspended Solids
The total amount of particulate material suspended in lake water, including sediment, algae, and organic matter, measured in milligrams per liter.
Trophic State Index
The Carlson Trophic State Index (TSI) is a numerical scale from 0 to 100 that classifies lakes by their nutrient and productivity levels.
Ecology
Algal Bloom
A rapid increase in algae population in a lake, often visible as green discoloration or surface scums, triggered by warm temperatures and excess nutrients.
Aquatic Macrophytes
Visible aquatic plants growing in lakes, including emergent, floating-leaf, and submersed species that provide critical habitat and help maintain water quality.
Blue-Green Algae
The common name for cyanobacteria, photosynthetic bacteria that form potentially toxic blooms in nutrient-rich lakes during warm weather.
Cyanobacteria
Photosynthetic bacteria (commonly called blue-green algae) that can form harmful blooms and produce toxins dangerous to humans and animals.
Eurasian Watermilfoil
An aggressive invasive aquatic plant that forms dense surface mats, displaces native vegetation, and impairs swimming, boating, and fishing.
Eutrophic
A lake classification indicating high nutrient levels, reduced clarity, and frequent algae blooms, a nutrient-rich and highly productive lake.
Hypereutrophic
A lake classification indicating excessive nutrient levels, very poor clarity, and persistent algae blooms, the most impaired category.
Invasive Species
Non-native organisms that spread aggressively in lake ecosystems, outcompeting native species and often degrading water quality and habitat.
Lake Stratification
The separation of a lake into distinct temperature layers during summer, with warm water on top and cold water on the bottom.
Lake Turnover
The seasonal mixing event when surface and deep water layers in a stratified lake exchange positions, driven by temperature equalization.
Mesotrophic
A lake classification indicating moderate nutrient levels, reasonable clarity, and balanced algae growth, the middle category between oligotrophic and eutrophic.
Oligotrophic
A lake classification indicating low nutrient levels, high water clarity, and minimal algae growth, the cleanest category of lake.
Thermocline
The transition layer in a stratified lake where water temperature changes rapidly with depth, separating warm surface water from cold deep water.
Zebra Mussels
Small, striped freshwater mussels native to Eastern Europe that attach to hard surfaces in lakes, filter large volumes of water, and alter lake ecosystems.
Pollutants
Agricultural Runoff
Water flowing off cropland, feedlots, and pastures that carries fertilizer, manure, pesticides, and eroded soil into lakes and streams.
Nonpoint Source Pollution
Water pollution from diffuse sources across the landscape, including agricultural fields, lawns, streets, and construction sites, rather than from a single identifiable discharge point.
Point Source Pollution
Water pollution from a single identifiable source, such as a factory discharge pipe or wastewater treatment plant outfall.
Septic System Impact
The contribution of failing or inadequate septic systems to lake pollution, particularly through phosphorus and bacterial contamination.
Stormwater Runoff
Rainwater and snowmelt that flows across impervious surfaces like roads, driveways, and rooftops, carrying pollutants into lakes and streams.
Management
Lake Management Plan
A comprehensive strategy developed by lake associations, local governments, and agencies to protect or restore water quality in a specific lake.
Shoreline Buffer
A strip of natural vegetation maintained along a lake shoreline to filter runoff, stabilize soil, and provide wildlife habitat.
Water Quality Monitoring
The systematic collection and analysis of water samples and measurements to track lake health over time and detect changes in water quality.
Watershed
The entire land area that drains water, sediment, and nutrients into a particular lake, the primary factor determining lake water quality.
Recreation
360
A full 360-degree rotation of board and rider, most commonly performed flat on the water's surface in skim style.
Aerial
Any movement in which the rider leaves the water, with or without the board.
Air
Launching off the lip with the board into the air and landing back on the wake with the nose still facing forward.
Air 360
A 360-degree rotation performed in the air off the lip rather than spun flat on the surface.
Backside
A turn or rotation done toward the heel side of the board (back facing the wave), away from the rider's chest.
Bail
Deliberately jumping off the board mid-ride to avoid a worse, harder fall.
Ballast
Added weight (water-filled bags or hard weights) placed in the boat to sink the hull deeper and build a bigger, more defined wake.
Ballast Pump
The electric pump that moves water into and out of a boat's ballast tanks or sacs, available as reversible flexible-impeller pumps or one-directional aerator pumps.
Big spin
A combination trick pairing a 360-degree shuv-it of the board with a 180-degree body varial in the same direction.
Bimini
A canvas sun canopy, often mounted to the wakeboard tower, that shades the cockpit while preserving the open feel and headroom of a wake boat.
Board Length
The overall length of a wakesurf board, sized to rider weight and skill—longer boards float and catch waves more easily, shorter boards turn and spin more readily.
Board Rack
A clamp or holder mounted to a wakeboard tower that stores wakesurf and wakeboard boards securely out of the cockpit while underway.
Board slide
Sliding the board 90 degrees across the crest of the wake for at least a second, tail crossing first with the rider facing the boat.
Boat speed
The boat's pace while surfing, typically around 10-12.5 mph, which strongly affects wave size and shape.
Body varial
Jumping and spinning your body 180 degrees while the board stays pointing in the same direction.
Bottom turn
A turn made at the base of the wave to redirect the board back up the face, setting up the next maneuver.
Bow Rise
How high the boat's bow sits out of the water at surf speed, a trim characteristic tuned with ballast and the wedge to shape the wave's length and steepness.
Bow weight
Ballast loaded toward the front of the boat, which flattens the wake slightly but increases its length and smoothness.
Burble
The turbulent low-pressure pocket of air directly behind a moving boat's transom where exhaust and carbon monoxide collect.
Carbon monoxide
The odorless, colorless gas in boat exhaust that accumulates behind the transom and poses a serious poisoning and drowning risk to riders close to the boat.
Carving
Drawing smooth, arcing turns up and down the wave face on rail, the signature flowing maneuver of surf-style wakesurfing.
Chop
Small, disorganized surface waves from wind or boat traffic that degrade the smooth wave face and make riding harder.
Clean wave
A wake with a smooth, well-defined curling face and minimal turbulence, the ideal surfable shape produced by proper boat setup.
Compression Molded
A durable, machine-pressed wakesurf board construction with a smooth finish, common on entry-level and value boards for resilience and dependability.
Convex V Hull
Tige's hull design that, combined with TAPS, enables full trim adjustment and is engineered specifically to produce a long, clean wakesurf wave.
Convex VX
Tige's fiberglass hull-extension device that attaches to the swim platform and extends the running surface, channeling propeller water down into the wave to increase its size, volume, and density.
Curl
The steepest breaking part of the wave where it pitches over into whitewash, marking the powerful edge of the pocket.
Cutback
A turn that takes the rider up toward the top of the wave and then arcs back down toward its base, redirecting flow back into the pocket.
Deck
The top surface of the wakesurf board where the rider stands, usually finished with a grippy traction pad.
Deep-water start
The technique for getting up on a wakesurf board from a floating position, letting the boat's pull bring you upright with arms straight and knees bent.
Displacement Hull
A deep, displacement-style wake-boat hull that pushes a large volume of water aside at slow surf speeds to throw a tall, clean, long-pushing wakesurf wave.
Distance from shore
Legal minimum buffers (commonly 150-200 feet) that towing boats must keep from shore, docks, swimmers, and other vessels.
Double up
When the energy of two waves combines into one larger wave, sometimes used off a turn-around to add power for a hit.
Driver
The person operating the boat, responsible for throttle, course, speed, and the rider's safety, working alongside a separate spotter.
Drop the rope
Releasing the tow rope once balanced in the wave's push zone so you can surf the wake free of any line, the defining moment of wakesurfing.
EVA Traction
The grippy foam (ethylene-vinyl acetate) pad on a wakesurf board's deck that gives the rider's feet a comfortable, secure standing surface.
Face
The unbroken sloping front of the wave between the lip and the trough, where riders generate speed and perform maneuvers.
Fall zone
The area of water immediately behind the boat near the propeller where a fallen rider is at greatest risk, prompting an immediate engine shutdown.
Fat Sac
A soft, fillable PVC ballast bag placed in a boat's lockers or floor to add water weight for wakesurfing, named after FatSac, the original and best-known ballast-bag manufacturer.
Fin
A blade fixed under the tail of the board that stabilizes its trajectory and provides drive and hold through turns.
Fish Consumption Advisory
Official guidance from state health departments recommending limits on eating fish from specific lakes due to mercury, PCBs, or other contaminants.
Forward Drive
A drive system with dual counter-rotating propellers mounted at the front of the drive unit, tucked safely under the hull, allowing some sterndrive-based boats to wakesurf safely.
Fresh air exhaust
An exhaust system that injects engine fumes into the propeller wash and underwater, dramatically lowering carbon monoxide around the rider.
Frontside
A turn or rotation done toward the toe side of the board (chest facing the wave), the direction a rider faces the wave through the turn.
Gen 2 Surf System
MasterCraft's integrated surf system, built on four pillars—hull design, customized weight, a custom wake-shaping device, and unifying software—that fills tanks and bags and deploys the shaping device for a chosen surf side in minutes.
Glass / glassy
Perfectly calm, mirror-smooth water with no chop, the ideal surface for a clean wakesurf wave.
Grab
An air in which the rider grabs a rail of the board with one hand while airborne.
Hand signals
A standardized set of gestures the rider and spotter use to communicate speed, direction, status, and stopping over engine noise and distance.
Handle
The grip at the end of the wakesurf rope that the rider holds during the deep-water start before dropping the rope.
Hard Tank
A rigid, molded ballast tank built below the floor of a wake boat that holds water weight without occupying storage or seating space and avoids the mildew issues of soft bags.
Hybrid Board
A wakesurf board blending surf-style thickness and buoyancy with a more skim-like nose and tail shape, offering both stability and spinnability across skill levels.
Inboard
A boat with the engine mounted inside the hull and the propeller exiting under the hull forward of the transom, making it safe for wakesurfing because the rider stays away from the prop.
Integrated Ballast System (IBS)
A factory ballast configuration combining built-in hard tanks with plumbed auxiliary sacs, controlled by the boat's helm so the whole system fills and drains for a chosen surf side automatically.
Kill switch
An engine cut-off lanyard or wireless device that stops the engine instantly, killing the propeller if the driver is displaced or a rider is endangered.
Lip
The top edge or crest of the wave, the powerful upper section where riders throw slashes, off-the-lip turns, and launch airs.
Lip slide
Sliding the board 90 degrees across the crest of the wake for at least a second, nose crossing first with the rider facing away from the boat.
List
Tilting the boat to one side by weighting it asymmetrically so the wake breaks cleanly on the side the rider is surfing.
List / Lean
The side-to-side tilt of the boat toward the surf side, created by surf-side ballast or a surf system, that forms the clean one-sided wakesurf wave.
Nautique Surf System (NSS)
Nautique's surf system that deploys a Waveplate extending outward and down from the transom under the swim step to intercept and redirect water flow, cleaning up the wake and forming a surf wave.
Observer law
State and local regulations requiring a qualified observer (spotter) aboard, in addition to the driver, whenever a rider is being towed.
Offshore wind
Wind blowing from the land toward the water, which tends to groom and clean the wave face, considered favorable.
Ollie
Jumping the board off the water to get air without using the wake's lip as a ramp.
Onshore wind
Wind blowing from the water toward the land, which roughens the surface and degrades the wave, considered unfavorable.
Opti-V Hull
Centurion's hull design, anchoring the brand's surf system and credited with producing some of the longest production-tier wakesurf waves on the market.
PerfectPass
A popular GPS-based aftermarket speed-control system for inboard ski and wake boats that holds a set speed within plus or minus half a mph for consistent wakesurf waves.
PFD / life jacket
A U.S. Coast Guard-approved personal flotation device that wakesurfers must wear; inflatable PFDs are not allowed for towed watersports.
Plumbed Ballast
A permanently installed ballast system with fixed plumbing—pumps, hoses, intakes, vents, and drains—that fills and empties hard tanks or sacs automatically without manual hoses.
The steepest, most powerful section of the wave next to the white water, where the push is strongest and where riders want to stay.
Pop
The snap a rider uses to spring the board off the water surface or lip to initiate ollies, shuv-its, and airs.
Power Wedge
Malibu and Axis's branded transom hydrofoil (current Power Wedge III) that lowers the stern to add wave size and adjust face length, offering six settings plus an on-plane Lift Mode.
Propeller safety
The set of practices that keep riders away from the spinning propeller, including using only inboard boats and shutting the engine off before anyone is near the stern.
Pumping
Turning rhythmically up and down the face of the wake to generate speed and maintain momentum without the rope.
Punt
Any aerial maneuver where the rider leaves the water, with or without the board; a synonym for an air.
Push
The forward force a wakesurf wave exerts on the board that propels the rider and keeps them with the boat once the rope is released.
Push / sweet spot
The clean section of the wave that propels the rider forward without the rope; finding it is what lets you ride hands-free.
Quad Fin
A four-fin setup using two pairs of fins to combine the speed and drive of a twin with extra hold, popular for fast, drivey surf-style riding.
Rail
The edge of the wakesurf board running along each side, which the rider leans onto to carve and which can be grabbed in airs.
Rails
The edges of a wakesurf board running nose to tail; rounder (rolled) rails are forgiving for beginners, while sharper rails bite harder for advanced carving.
RAMFILL
Centurion and Supra's fast-fill ballast technology that fills the boat's hard tanks in roughly 90 seconds for quick surf-ready setup and side switches.
Regular vs goofy
Your natural riding stance: regular means left foot forward, goofy means right foot forward.
Rocker
The curve of the board from nose to tail; more rocker turns more easily, less (flatter) rocker rides faster and looser.
Rooster tail
The plume of spray thrown up where the boat's wake converges behind the transom, a visual marker of the wash directly behind the boat.
Rope / tow rope
The short, low-stretch line used to pull the rider up and into the wave before they drop it; wakesurf ropes are much shorter than wakeboard ropes.
Shuv-it
Spinning only the board 180 (or 360) degrees beneath the feet while the rider's body stays facing the same direction.
Single Fin
A one-fin setup, standard on most skim-style boards, where a small center fin gives forward drive but breaks free easily for surface spins and shuvits.
Skim style
A wakesurfing discipline using flatter, thinner, low-rocker boards with little or no fin, built for spins, shuv-its, slides, and skateboard-like freestyle.
Skim-Style Board
A thinner, smaller, lower-volume wakesurf board with a flat rocker, symmetrical shape, and small or single fins that feels slippery and is built for spins, airs, and skate-style tricks.
Slash
An aggressive, spray-throwing turn off the top of the wave near the lip, redirecting the board sharply back down the face.
Speed Control
An electronic system that holds a precise, preset boat speed regardless of load, water conditions, or driver input—critical for consistent wave shape while wakesurfing.
Spotter
A required second person on the boat who watches the surfer at all times so the driver can focus solely on driving.
Spotter / observer
A dedicated second person besides the driver whose only job is to watch the rider and relay their status, legally required in most jurisdictions for towed watersports.
Spray
The fan of water thrown off the board during a hard turn or slash, both a stylistic flourish and a sign of an aggressive, committed maneuver.
Stern weight
Ballast loaded toward the rear of the boat, which creates a taller, steeper wave with less length.
Surf Band
Malibu's patented wrist-worn wireless remote that lets the surfer change the wave's size, length, shape, speed, and side from the water by commanding the Surf Gate and Power Wedge.
Surf gate
A built-in surf system that diverts water flow off one side of the transom to shape a clean surf wave and switch sides at the push of a button.
Surf side
The side of the wake, regular or goofy, that the boat is set up to surf, selectable on modern boats at the push of a button.
Surf Speed
The slow boat speed used for wakesurfing, typically around 10-12 mph, held steady by speed control to keep the wave shape consistent.
Surf style
A wakesurfing discipline using thicker, more buoyant, finned boards built to emulate ocean surfing, favoring deep carves and flowing turns on the wave face.
Surf System
A boat-mounted device that redirects water flow at the transom to shape a clean, surfable wave on either side at the push of a button, eliminating the need to physically lean and re-weight the boat to switch sides.
Surf Tabs
MasterCraft's 2009 wake-shaping device, recognized as the first-ever production wakesurf shaping tab and the predecessor to the Gen 2 Surf System.
Surf-Style Board
A thicker, higher-volume wakesurf board with a shaped tail and larger fins that floats high, catches the wave easily, and is the most beginner-friendly style.
Sweet Spot
The optimal riding zone within the wave's pocket where the rider gets the most speed and push and can ride hands-free.
Swim Platform
The flat deck at the stern of a wake boat where surfers stage and from which the wave forms, and the mounting point for some wave-shaping hull extensions.
Switch / fakie
Riding with the opposite foot forward from your natural stance.
Tail Shape
The outline of a wakesurf board's tail—such as squash, square, fish, or swallowtail—that influences drive, looseness, and how easily the board holds in the wave.
TAPS
Tige's Trim Adjustable Performance System, an adjustable transom-mounted wave shaper that, combined with the Convex V hull, gives the boat full trim capability and dials in the surf wave on either side.
Teak surfing
The dangerous, often illegal practice of holding onto a boat's swim platform to bodysurf the wake, exposing the rider directly to lethal carbon monoxide.
Throttle control
The driver's smooth management of engine power to bring the rider up gently and then hold a precise, steady surf speed.
Thruster
A three-fin setup—two outer fins for speed plus a center fin for stability—that is the most common configuration on surf-style boards, delivering drive and grip for big bottom turns.
Traction pad
The textured foam grip on the board's deck that keeps the rider's feet planted in place of surf wax.
Transfer
An advanced maneuver in which the rider crosses from one side of the wake to the other and back, transferring across the boat's wash.
Trim Plate
An adjustable plate or tab at the transom that changes the boat's running attitude (trim), used to fine-tune wave length, steepness, and the bow's rise out of the water.
Trim tab / hull plate
Adjustable plates on the hull that, alongside surf systems, fine-tune the boat's running attitude to dial in wave shape.
Trough
The lowest point of the wave at the base of the face, where there is little power or momentum.
Twin Fin
A two-fin setup using outside fins that generates speed and down-the-line drive with plenty of hold, yet still releases for tricks—often compared to riding a skateboard.
V-Drive
An inboard drivetrain in which the engine sits at the stern facing backward and the driveshaft runs forward, placing the propeller safely beneath the hull ahead of the transom—the standard layout for wakesurf boats.
Vent Line
The overflow tube on a ballast bag that lets trapped air escape so the bag fills fully and prevents it from overfilling beyond its compartment.
Volume
The thickness and buoyancy of a wakesurf board; higher volume floats and carries beginners better, lower volume rides looser.
Wake
The wave thrown off the stern of a moving boat, which the wakesurfer rides; on a properly set-up wake boat it forms a continuous, surfable face.
Wakeboard Tower
An elevated A-frame structure over the boat's cockpit that raises the tow point and provides mounting for board racks, speakers, lights, and a bimini.
Wakesurf Board
A short, buoyant board, typically a surf, skim, or hybrid style, ridden on a boat's wave without a rope once the rider drops into the pocket.
Wakesurf Rope
A short, low-stretch tow rope, typically 60-75 feet long, with multiple grab points or knots that the rider uses only to get up and into the wave before throwing it back.
Wakesurfing
A towed watersport in which a rider surfs the wake created by a specialized inboard boat, releasing the tow rope to ride the wave free of any line.
Wave Face
The clean, unbroken sloping surface of the wave that a wakesurfer rides on, ahead of the curl and whitewash.
Wave length
How long the rideable wave face is from front to back, lengthened by bow weight and higher speed, shortened by stern weight and lower speed.
Wave shaper
An aftermarket device mounted on the transom or hull that disrupts and shapes the water flow to clean up the wash and lengthen the pocket.
Wedge
A deployable underwater foil at the transom that pulls the stern down and shapes the wake, used by Malibu (Power Wedge) and Axis to add wave size and adjust length without additional ballast.
Wetsuit
A neoprene rubber suit worn to keep the rider warm in cold water and air.
White wash
The foamy, broken, turbulent part of the wake behind the clean face; riders try to stay ahead of it in the clean pocket.
Whitewash
The rolling wall of foam left behind after a wave breaks, sitting just behind the curl at the back of a wakesurf wave's rideable face.
Wipeout
Falling off the board while riding the wave; in wakesurfing falls are usually gentle because of the low boat speed.
Understanding Your Lake Report Card
LakeQuality assigns A-through-F grades from nutrients and algae — phosphorus, nitrogen, chlorophyll-a, and turbidity — scored against EPA National Lakes Assessment condition classes for that lake's ecoregion. Water clarity (Secchi depth) is measured and shown; it is not scored. The trophic state index is reported as a measurement and classified only when the lake is rated. Look up any term above to learn how it affects your lake's grade.