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18-789: Lake Helen or Helen Lake may refer to several places: United States [ edit ] Helen Lake , Montana Lake Helen, Florida , a city in Florida Lake Helen (Portage County, Wisconsin) Lake Helen (Wyoming) , a lake in the Big Horn Mountains Lake Helen (California) , a lake in Northern California Canada [ edit ] Helen Lake (Vancouver Island) Lake Helen 53A - First Nations reserve in Ontario, located on

36-529: A slow recession . Because the peak flow also corresponds to the maximum water level reached during the event, it is of interest in flood studies. Analysis of the relationship between precipitation intensity and duration and the response of the stream discharge are aided by the concept of the unit hydrograph , which represents the response of stream discharge over time to the application of a hypothetical "unit" amount and duration of rainfall (e.g., half an inch over one hour). The amount of precipitation correlates to

54-399: Is a measure of the quantity of any fluid flow over unit time. The quantity may be either volume or mass. Thus the water discharge of a tap (faucet) can be measured with a measuring jug and a stopwatch. Here the discharge might be 1 litre per 15 seconds, equivalent to 67 ml/second or 4 litres/minute. This is an average measure. For measuring the discharge of a river we need a different method and

72-685: Is different from Wikidata All article disambiguation pages All disambiguation pages Helen Lake Coordinates : 48°50′16″N 113°45′24″W  /  48.83778°N 113.75667°W  / 48.83778; -113.75667 This article is about the lake in Montana. For the lake on British Columbia's Vancouver Island, see Helen Lake (Vancouver Island) . Helen Lake [REDACTED] Helen Lake, July 2009 [REDACTED] [REDACTED] Helen Lake Show map of Montana [REDACTED] [REDACTED] Helen Lake Show map of

90-603: Is located in Glacier National Park , in the U.S. state of Montana . Helen Lake is at the head of the Belly River and is situated below Ahern Peak to the west and Ipasha Peak to the northwest. Numerous small streams feed the lake in addition to melt waters from the Ahern Glacier which descend 1,680 feet (510 m) over Ahern Glacier Falls in one sheer drop to a talus slope below en route to

108-416: Is the sum of processes within the hydrologic cycle that increase the water levels of bodies of water. Most precipitation occurs directly over bodies of water such as the oceans, or on land as surface runoff . A portion of runoff enters streams and rivers, and another portion soaks into the ground as groundwater seepage . The rest soaks into the ground as infiltration, some of which infiltrates deep into

126-404: Is typically expressed in units of cubic meters per second (m³/s) or cubic feet per second (cfs). The catchment of a river above a certain location is determined by the surface area of all land which drains toward the river from above that point. The river's discharge at that location depends on the rainfall on the catchment or drainage area and the inflow or outflow of groundwater to or from

144-535: The Rhine river in Europe is 2,200 cubic metres per second (78,000 cu ft/s) or 190,000,000 cubic metres (150,000 acre⋅ft) per day. Because of the difficulties of measurement, a stream gauge is often used at a fixed location on the stream or river. A hydrograph is a graph showing the rate of flow (discharge) versus time past a specific point in a river, channel, or conduit carrying flow. The rate of flow

162-628: The United States Location Glacier National Park , Glacier County, Montana , U.S. Coordinates 48°50′16″N 113°45′24″W  /  48.83778°N 113.75667°W  / 48.83778; -113.75667 Lake type Natural Primary outflows Belly River Basin  countries United States Max. length 1 mi (1.6 km) Max. width 0.30 mi (0.48 km) Surface elevation 5,085 ft (1,550 m) Helen Lake

180-399: The area, stream modifications such as dams and irrigation diversions, as well as evaporation and evapotranspiration from the area's land and plant surfaces. In storm hydrology, an important consideration is the stream's discharge hydrograph, a record of how the discharge varies over time after a precipitation event. The stream rises to a peak flow after each precipitation event, then falls in

198-485: The corresponding discharge from the rating curve. If a continuous level-recording device is located at a rated cross-section, the stream's discharge may be continuously determined. Larger flows (higher discharges) can transport more sediment and larger particles downstream than smaller flows due to their greater force. Larger flows can also erode stream banks and damage public infrastructure. G. H. Dury and M. J. Bradshaw are two geographers who devised models showing

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216-418: The discharge of a river is based on a simplified form of the continuity equation . The equation implies that for any incompressible fluid, such as liquid water, the discharge (Q) is equal to the product of the stream's cross-sectional area (A) and its mean velocity ( u ¯ {\displaystyle {\bar {u}}} ), and is written as: where For example, the average discharge of

234-1076: The lake. See also [ edit ] List of lakes in Glacier County, Montana References [ edit ] ^ "Helen Lake" . Geographic Names Information System . United States Geological Survey , United States Department of the Interior . Retrieved 2011-01-29 . ^ "Ahern Pass, MT" (Map (USGS Quad)) . TopoQuest . Retrieved 2011-01-29 . ^ "Ahern Glacier Falls" . World Waterfall Database. 2004 . Retrieved 2011-01-29 . Retrieved from " https://en.wikipedia.org/w/index.php?title=Helen_Lake&oldid=980138649 " Categories : Lakes of Glacier National Park (U.S.) Lakes of Glacier County, Montana Hidden categories: Pages using gadget WikiMiniAtlas Coordinates on Wikidata Articles using infobox body of water without alt Articles using infobox body of water without image bathymetry Discharge (hydrology) A discharge

252-424: The level of the stream is described by a rating curve . Average velocities and the cross-sectional area of the stream are measured for a given stream level. The velocity and the area give the discharge for that level. After measurements are made for several different levels, a rating table or rating curve may be developed. Once rated, the discharge in the stream may be determined by measuring the level, and determining

270-577: The most common is the 'area-velocity' method. The area is the cross sectional area across a river and the average velocity across that section needs to be measured for a unit time, commonly a minute. Measurement of cross sectional area and average velocity, although simple in concept, are frequently non-trivial to determine. The units that are typically used to express discharge in streams or rivers include m /s (cubic meters per second), ft /s (cubic feet per second or cfs) and/or acre-feet per day. A commonly applied methodology for measuring, and estimating,

288-583: The namesake Lake Helen See also [ edit ] Helen (disambiguation) Lake St. Helen , Michigan [REDACTED] Topics referred to by the same term This disambiguation page lists articles about distinct geographical locations with the same name. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Lake_Helen&oldid=1029911670 " Category : Place name disambiguation pages Hidden categories: Short description

306-583: The relationship between discharge and other variables in a river. The Bradshaw model described how pebble size and other variables change from source to mouth; while Dury considered the relationships between discharge and variables such as stream slope and friction. These follow from the ideas presented by Leopold, Wolman and Miller in Fluvial Processes in Geomorphology . and on land use affecting river discharge and bedload supply. Inflow

324-420: The volume of water (depending on the area of the catchment) that subsequently flows out of the river. Using the unit hydrograph method, actual historical rainfalls can be modeled mathematically to confirm characteristics of historical floods, and hypothetical "design storms" can be created for comparison to observed stream responses. The relationship between the discharge in the stream at a given cross-section and

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