Lake retention time


Lake retention time is a calculated quantity expressing the mean time that water spends in a particular lake. At its simplest, this figure is the result of dividing the lake volume by the flow into or out of the lake. It roughly expresses the amount of time taken for a substance introduced into a lake to flow out of it again. The retention time is particularly important where downstream flooding or pollutants are concerned.

Global retention time

The global retention time for a lake is calculated by dividing the lake volume by either the mean rate of inflow of all tributaries, or by the mean rate of outflow. This metric assumes that water in the lake is well-mixed, so that any portion of the lake water is much like any other. In reality, larger and deeper lakes are generally not well-mixed. Many large lakes can be divided into distinct portions with only limited flow between them. Deep lakes are generally stratified, with deeper water mixing infrequently with surface water. These are often better modeled as several distinct sub-volumes of water.

More specific residence times

It is possible to calculate more specific residence time figures for a particular lake, such as individual residence times for sub-volumes, or a residence time distribution for the various layers of a stratified lake. These figures can often better express the hydrodynamics of the lake. However, any such approach remains a simplification and must be guided by an understanding of the processes operating in the lake.
Two approaches can be used to elucidate how a particular lake works: field measurements and mathematical modeling. One common technique for field measurement is to introduce a tracer into the lake and monitor its movement. This can be a solid tracer, such as a float constructed to be neutrally buoyant within a particular water layer, or sometimes a liquid. This approach is sometimes referred to as using a Lagrangian reference frame. Another field measurement approach, using an Eulerian reference frame, is to capture various properties of the lake water at various fixed positions in the lake. From these can be constructed an understanding of the dominant processes operating in the various parts of the lake and their range and duration.
Field measurements alone are usually not a reliable basis for generating residence times, mainly because they necessarily represent a small subset of locations and conditions. Therefore, the measurements are generally used as the input for numerical models. In theory it would be possible to integrate a system of hydrodynamic equations with variable boundary conditions over a very long period sufficient for inflowing water particles to exit the lake. One could then calculate the traveling times of the particles using a Lagrangian method. However, this approach exceeds the detail available in current hydrodynamic models and the capacity of current computer resources. Instead, residence time models developed for gas and fluid dynamics, chemical engineering, and bio-hydrodynamics can be adapted to generate residence times for sub-volumes of lakes.

Renewal time

One useful mathematical model is the measurement of how quickly inflows are able to refill a lake. Renewal time is a specific measure of retention time, where the focus is on 'how long does it take to completely replace all water in a lake.' This is modeling can only be done with an accurate budget of all water gained and lost by the system. Renewal time simply becomes a question how quickly could the inflows of the lake fill the entire volume of the basin. For example if Lake Michigan was emptied, it would take 99 years for its tributaries to completely refill the lake.

List of residence times of lake water

The residence time listed is taken from the infobox in the associated article unless otherwise specified.
LakeLocationBasin countriesResidence time
Stausee FerdenFerden, ValaisSwitzerland
Lake Wohlen / WohlenseeCanton of BernSwitzerland
Lake HévízHévízHungary
Lake St. ClairGreat LakesCanada, United States
Lake ArapuniNorth IslandNew Zealand
Milton PondStrafford County, New Hampshire, York County, MaineUnited States
Gibson LakeGibson Generating Station, Princeton, IndianaUnited States
Råcksta TräskStockholmSweden
Lake SagamiKanagawaJapan
Lake CristallinaTicinoSwitzerland
Northeast PondStrafford County, New Hampshire; York County, MaineUnited States
Brandy PondNaples, MaineUnited States
Champagne PoolWaiotapu, North IslandNew Zealand
Prospect reservoirProspect, New South WalesAustralia
SicklasjönStockholmSweden
Devils LakeLincoln County, OregonUnited States
Lough DergShannon River BasinIreland
DerwentwaterLake District, CumbriaEngland
Lake Biel / Bielersee / Lac de BienneCanton of BernSwitzerland
VeluwemeerFlevoland, GelderlandNetherlands
HacksjönTullingeSweden
Kamloops LakeBritish ColumbiaCanada
Malham TarnNorth YorkshireEngland
Lac d'AnternePassy, Haute-SavoieFrance
Graham LakeHancock County, MaineUnited States
Grand Lac de ClairvauxJura department, Franche-ComtéFrance
LaduvikenDjurgårdenSweden
Esthwaite WaterLake District, CumbriaEngland
TrehörningenHuddinge, Southern Stockholm CountySweden
Lac de DivonneDivonne-les-Bains, AinFrance
Lake Lesina / Lago di LesinaProvince of Foggia, ApuliaItaly
SeeweidseeCanton of ZurichSwitzerland
HüttnerseeHütten, Canton of ZurichSwitzerland
Lake Lauerz / LauerzerseeCanton of SchwyzSwitzerland
Morris LakeHalifax Regional Municipality, Nova ScotiaCanada
Sobradinho ReservoirSobradinho, BahiaBrazil
Balch PondCarroll County, New Hampshire; York County, MaineUnited States
MagelungenHuddingeSweden
Russell LakeHalifax Regional Municipality, Nova ScotiaCanada
LoweswaterLake District, CumbriaEngland
LappkärretStockholmSweden
Lough FeeaghCounty MayoIreland
EgelseeBubikon, Canton of ZurichSwitzerland
Lac de VouglansJura, Franche-ComtéFrance
MettmenhasliseeCanton of ZurichSwitzerland
AlbysjönStockholmSweden
Chesuncook LakePiscataquis County, MaineUnited States
Clinton LakeDeWitt County, IllinoisUnited States
Flagstaff LakeSomerset County and Franklin County, MaineUnited States
Lake Coeur d'AleneNorthern IdahoUnited States
Lac de Saint-PointDoubs department, Franche-ComtéFrance
KyrksjönBrommaSweden
Newnan's LakeGainesville, FloridaUnited States
Staples PondTemple, MaineUnited States
Lac CornuChamonix-Mont-Blanc, Haute-SavoieFrance
Lac du BréventChamonix, Haute-SavoieFrance
Lake Silvaplana / Silvaplanersee / Lej da SilvaplaunaEngadin, GrisonsSwitzerland
Loch AweArgyll and ButeScotland
LångsjönStockholmSweden
Lake Sarnen / SarnerseeObwaldenSwitzerland
Lake LovozeroKola Peninsula, Murmansk OblastRussia
DrevvikenStockholmSweden
MörtsjönHuddingeSweden
JudarnBromma, StockholmSweden
Coniston WaterLake District, CumbriaEngland
UllswaterLake District, CumbriaEngland
Khanka LakeHeilongjiang Province, China and Primorsky Krai, RussiaChina, Russia
Lake MononaDane County, WisconsinUnited States
Long LakeMaineUnited States
Mooselookmeguntic LakeFranklin County, MaineUnited States
GreifenseeCanton of ZurichSwitzerland
Nainital LakeUttarakhandIndia
Manasbal LakeKashmir ValleyIndia
Lake Zurich / ZürichseeZürichSwitzerland
TegernseeBavariaGermany
Deer Creek ReservoirUtahUnited States
OrlångenHuddingeSweden
Haweswater ReservoirLake District, CumbriaEngland
Loch ShielLochaber, HighlandScotland
Lake Walen /Walensee / Lake Walenstadt St. Gallen, GlarusSwitzerland
Keoka LakeMaineUnited States
Kootenay LakeBritish ColumbiaCanada
Lake Murten /Lac de Morat /MurtenseeCanton of Fribourg, VaudSwitzerland
Oeschinen LakeBernese OberlandSwitzerland
Lac de LessyHaute-SavoieFrance
East Grand LakeMaine / New BrunswickCanada, United States
Lake IkedaKyūshū islandJapan
Lake PoyangJiujiangChina
Faaker SeeCarinthiaAustria
Ossiacher See / Lake OssiachCarinthiaAustria
Varese Lake/Lago di VareseProvince of Varese, LombardyItaly
Long Lost LakeClearwater County, MinnesotaUnited States
ÄltasjönÄltaSweden
Lake Thun / ThunerseeCanton of BernSwitzerland
Green LakeMaineUnited States
GömmarenHuddingeSweden
Loch LomondDunbartonshire, Central ScotlandScotland
Lake BalatonHungaryHungary
Lake RotoroaHamilton, Waikato, North IslandNew Zealand
Lake TūtiraHawke's Bay, North IslandNew Zealand
TürlerseeCanton of ZurichSwitzerland
PfäffikerseeCanton of ZurichSwitzerland
Caniapiscau ReservoirQuebecCanada
Lake Sils / Silsersee /Lej da SeglEngadin, GrisonsSwitzerland
WilerseeCanton of ZugSwitzerland
Great PondMaineUnited States
Moberly LakeBritish ColumbiaCanada
PäijänneJyväskyläFinland
Lake ErieNorth AmericaCanada, United States
Rangeley LakeFranklin County, MaineUnited States
Lake Brienz / BrienzerseeCanton of BernSwitzerland
Ammersee / Lake AmmerUpper BavariaGermany
Großer Plöner SeeSchleswig-HolsteinGermany
Paudash LakeHaliburton County, OntarioCanada
Moosehead LakeMaineUnited States
TrekantenStockholmSweden
Great East LakeCarroll County, New Hampshire; York County, MaineUnited States
Lake ChamplainNorth AmericaCanada, United States
Flathead LakeMontanaUnited States
Lake Lucerne /VierwaldstätterseeCentral SwitzerlandSwitzerland
Lake WinnipegManitoba, CanadaCanada
Lac de PaladruIsèreFrance
Lake Hallwil / HallwilerseeAargauSwitzerland
FlatenSouthern StockholmSweden
Lake Annecy / Lac d'AnnecyHaute-SavoieFrance
Lake Maggiore / Verbano / Lago MaggioreLombardy and Piedmont, Italy; Canton Ticino, SwitzerlandItaly, Switzerland
Todos los Santos LakeLos LagosChile
Lake Baldegg / BaldeggerseeCanton of LucerneSwitzerland
Lake Iseo / Lago d'IseoLombardyItaly
Lake Constance / BodenseeGermany, Switzerland, AustriaGermany, Switzerland, Austria
Corey LakeMichiganUnited States
Elk and Beaver LakesSaanich, British ColumbiaCanada
Lake ComoLombardyItaly
Lake MendotaWisconsinUnited States
Sea of GalileeGalileeIsrael
Walden PondMassachusettsUnited States
BannwaldseeAllgäu, BavariaGermany
Sebago LakeCumberland County, MaineUnited States
Kennisis LakeHaliburton Highlands, OntarioCanada
Bay LakeCrow Wing County, MinnesotaUnited States
Lake Biwa / 琵琶湖Shiga PrefectureJapan
Jordan PondHancock County, MaineUnited States
Lago di MergozzoPiedmontItaly
Lake OntarioNorth AmericaCanada, United States
Lac la NonneAlbertaCanada
Lago di CandiaProvince of TurinItaly
ÄgeriseeCanton of ZugSwitzerland
Loch MorarMorar, Lochaber, HighlandScotland
Lake PowellUtah/ArizonaUnited States
Millstätter See / Lake MillstattCarinthiaAustria
Moose LakeAlbertaCanada
SchaalseeSchleswig-HolsteinGermany
Iliamna LakeLake and Peninsula Borough, AlaskaUnited States
Lac du BourgetSavoie, FranceFrance
Odell LakeKlamath County, OregonUnited States
Lake Lugano /Lago di LuganoTicino, LombardySwitzerland, Italy
Lake Neuchâtel / Lac de Neuchâtel / NeuenburgerseeRomandySwitzerland
Lake Orta /Lago d’Orta /CusioPiedmontItaly
WeissenseeCarinthiaAustria
Quesnel LakeBritish ColumbiaCanada
Schweriner SeeMecklenburg-VorpommernGermany
Lake TaupōTaupō District, Waikato region, North IslandNew Zealand
Wörthersee / Lake WörthWest of KlagenfurtAustria
Lake ChelanWashingtonUnited States
Lake GenevaSwitzerland, FranceSwitzerland, France
Lake WakatipuQueenstown-Lakes District, Otago Region, South IslandNew Zealand
Higgins LakeMichiganUnited States
Crescent LakeKlamath County, OregonUnited States
Yellowstone LakeYellowstone National Park, WyomingUnited States14 years
Lake Zug / ZugerseeCentral SwitzerlandSwitzerland
MüritzMecklenburg-VorpommernGermany
Western Brook PondGros Morne National Park, Newfoundland, Newfoundland and LabradorCanada
Lake Sempach / SempacherseeCanton of LucerneSwitzerland
Skaneateles LakeNew YorkUnited States
Cayuga LakeNew YorkUnited States
Bear LakeIdaho, UtahUnited States
Green LakeGreen Lake County, WisconsinUnited States
Lake Starnberg /Starnberger SeeBavariaGermany
Lake HuronNorth AmericaCanada, United States
Lake Garda / Lago di GardaNorthern ItalyItaly
Waldo LakeCascade MountainsUnited States
Crystal LakeBenzie County, MichiganUnited States
Lake ColumbiaJackson County, MichiganUnited States
Okanagan LakeBritish ColumbiaCanada
Lake OhridAlbania, North Macedonia
Lake MichiganMichiganUnited States
ArendseeSaxony-AnhaltGermany
Gull LakeAlbertaCanada
Lake YosemiteCaliforniaUnited States
Great Bear LakeNorthwest TerritoriesCanada
Crater LakeOregonUnited States
Lake SuperiorNorth AmericaCanada, United States
Caspian SeaAzerbaijan, Iran, Kazakhstan, Russia, Turkmenistan
Lake BaikalSouthern SiberiaRussia
Lake TahoeCalifornia, NevadaUnited States
Lake TiticacaPeru, Bolivia
Lake EucumbeneSnowy Mountains, New South WalesAustralia
Lakes QabanKazanRussia
Lake TanganyikaBurundi, DR Congo, Tanzania, Zambia
Lake VostokAntarctica