Fallen Leaf Lake is a mountain lake located in El Dorado County, California , near the California – Nevada state border, about one mile south west of the much larger Lake Tahoe . It is approximately aligned north-to-south and oval in shape, measuring approximately 2.9 miles (4.6 km) on the long axis and 0.9 miles (1.4 km) on the short axis. The lake was created by at least two glaciers that traveled northward down the Glen Alpine Valley. If the glacier had continued instead of stopping, Fallen Leaf Lake would be a bay of Lake Tahoe, similar to nearby Emerald Bay . A terminal moraine is visible at the north end of the lake on the northeast edge.
49-678: Fallen Leaf Lake is located within the National Forest System lands managed by the Lake Tahoe Basin Management Unit , adjacent to El Dorado County . The land surrounding the lake is privately owned, leased from the U.S. Forest Service , and part of the Lake Tahoe Basin Management Unit. Like some areas where the Forest Service has leased land intermingled with private land, the two land types appear in
98-535: A concrete bridge spanning Glen Alpine Creek. Glen Alpine Road begins at the bridge and runs for about two miles southwest to Glen Alpine Springs, one of the trailheads to the Desolation Wilderness Area. Fallen Leaf Road itself continues northwesterly along the west side of the lake past the Stanford Sierra Camp . Cathedral Road also intersects State Route 89, and travels south to the houses on
147-403: A 16–20 feet (5–7 m) sailboat . The marina has room for approximately 60 boats, many of which are owned by property owners without direct access to the water. Wakeboard and waterski boats are the most common, followed by dedicated fishing boats, a few sailboats and pontoon boats , and some manually propelled craft. Kayaking is becoming more popular, as is recreational rowing . Fishing
196-647: A country have become erodible. For example, on the Madagascar high central plateau , which constitutes approximately ten percent of that country's land area, most of the land area is devegetated, and gullies have eroded into the underlying soil to form distinctive gulleys called lavakas . These are typically 40 meters (130 ft) wide, 80 meters (260 ft) long and 15 meters (49 ft) deep. Some areas have as many as 150 lavakas/square kilometer, and lavakas may account for 84% of all sediments carried off by rivers. This siltation results in discoloration of rivers to
245-465: A dark red brown color and leads to fish kills. In addition, sedimentation of river basins implies sediment management and siltation costs.The cost of removing an estimated 135 million m of accumulated sediments due to water erosion only is likely exceeding 2.3 billion euro (€) annually in the EU and UK, with large regional differences between countries. Erosion is also an issue in areas of modern farming, where
294-432: A grain, such as pits, fractures, ridges, and scratches. These are most commonly evaluated on quartz grains, because these retain their surface markings for long periods of time. Surface texture varies from polished to frosted, and can reveal the history of transport of the grain; for example, frosted grains are particularly characteristic of aeolian sediments, transported by wind. Evaluation of these features often requires
343-458: A higher density and viscosity . In typical rivers the largest carried sediment is of sand and gravel size, but larger floods can carry cobbles and even boulders . Wind results in the transportation of fine sediment and the formation of sand dune fields and soils from airborne dust. Glaciers carry a wide range of sediment sizes, and deposit it in moraines . The overall balance between sediment in transport and sediment being deposited on
392-426: A hydrodynamic sorting process within the marine environment leading to a seaward fining of sediment grain size. One cause of high sediment loads is slash and burn and shifting cultivation of tropical forests. When the ground surface is stripped of vegetation and then seared of all living organisms, the upper soils are vulnerable to both wind and water erosion. In a number of regions of the earth, entire sectors of
441-455: A long, low concrete dam with an adjustable spillway to control the rate at which the water leaves the lake. This dam is 12 ft (3.7 m) high and 265 ft (81 m) in length. Taylor Creek flows northward, passing under State Route 89, and enters Lake Tahoe at Baldwin Beach. Fallen Leaf is approximately 380 feet (116 m) deep at its deepest point, which is at the south end, east of
490-464: A mosaic or checkerboard pattern. Fallen Leaf Road is approximately 5 miles (8 km) long, and begins at State Route 89 , which runs along the south shore of Lake Tahoe. The road intersects the highway approximately half a mile (800 m) west of Camp Richardson , a resort and campground on the southern shore of Lake Tahoe. The road runs generally to the south, is one lane wide and paved, and has turnouts to allow cars to pass each other. The road passes
539-469: A part of LTBMU management or play a very small role. Since the lake is so dependent on all that happens around it, LTBMU programs manage the whole of the basin as a complete inter-dependent system. The LTBMU is a unique inter-mix of forest and urban communities, presenting challenges and complexities few other National Forests experience. Since its establishment in 1973, the LTBMU has become a pioneer and leader in
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#1732852025606588-470: A result, can cause exposed sediment to become more susceptible to erosion and delivery to the marine environment during rainfall events. Sediment can negatively affect corals in many ways, such as by physically smothering them, abrading their surfaces, causing corals to expend energy during sediment removal, and causing algal blooms that can ultimately lead to less space on the seafloor where juvenile corals (polyps) can settle. When sediments are introduced into
637-514: A ridge that leads in the direction of Gilmore Lake and Mount Tallac . Incidentally, Mount Tallac (9,735 ft (2,967 m)) is familiar to anyone who was a fan of the television series Bonanza as it appeared with its characteristic cross of snow behind the Cartwright family as they rode towards the camera. Cathedral Peak does not have a trail that leads directly to it, but can be reached by three different approaches. The Middle Trail to Tallac
686-462: A single "management unit." This unification provided the focus needed for the basin, and more effective management of its watershed, ecological and recreational values. The name "Lake Tahoe Basin Management Unit" was originally a temporary one, but after several decades, the name remains. 39°N 120°W / 39°N 120°W / 39; -120 Sediment Sediment
735-412: Is potable , and many homes along the shoreline run a pipe offshore to provide water during the winter when other water systems may be turned off. The water in the lake is exchanged every eight years, compared to the much deeper, therefore slower, Lake Tahoe, which exchanges every 700 years. The surface elevation of the lake is 152 feet (46 m) above Lake Tahoe. Mature conifer trees can be found on
784-572: Is a United States National Forest that manages and protects public land surrounding Lake Tahoe and the Lake Tahoe Basin . Straddling the state borders of California and Nevada in the Sierra Nevada , the LTBMU encompasses 154,851 acres (626 km ) of National Forest system lands, ranging in altitude above sea level from 6,225 feet (1,897 m) at lake level to 10,881 feet (3,317 m) at Freel Peak. The U.S. Forest Service established
833-1032: Is a naturally occurring material that is broken down by processes of weathering and erosion , and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation ; if buried, they may eventually become sandstone and siltstone ( sedimentary rocks ) through lithification . Sediments are most often transported by water ( fluvial processes ), but also wind ( aeolian processes ) and glaciers . Beach sands and river channel deposits are examples of fluvial transport and deposition , though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice-transported sediments. Sediment can be classified based on its grain size , grain shape, and composition. Sediment size
882-555: Is a trail that begins near Lily Lake and which runs along the northern side of Glen Alpine Valley. It runs up to a junction which splits off to Gilmore Lake and Mount Tallac. Intrepid hikers can set off cross-country in the general direction of Cathedral Peak, about half a mile (800 m) away. Another route is from Gilmore Lake, to the same junction. Finally, the Lake Trail begins at the end of Fallen Leaf Road and slowly climbs up to Cathedral Lake and Floating Island Lake, and eventually to
931-541: Is expected to be delivered to the outlet of the river. The sediment transfer and deposition can be modelled with sediment distribution models such as WaTEM/SEDEM. In Europe, according to WaTEM/SEDEM model estimates the Sediment Delivery Ratio is about 15%. Watershed development near coral reefs is a primary cause of sediment-related coral stress. The stripping of natural vegetation in the watershed for development exposes soil to increased wind and rainfall and, as
980-581: Is measured on a log base 2 scale, called the "Phi" scale, which classifies particles by size from "colloid" to "boulder". The shape of particles can be defined in terms of three parameters. The form is the overall shape of the particle, with common descriptions being spherical, platy, or rodlike. The roundness is a measure of how sharp grain corners are. This varies from well-rounded grains with smooth corners and edges to poorly rounded grains with sharp corners and edges. Finally, surface texture describes small-scale features such as scratches, pits, or ridges on
1029-505: Is popular, if not particularly productive, for brown trout , rainbow trout and lake trout . The Forest Service stocks the lake and Glen Alpine Creek, which improves anglers' odds. The lake has also seen what appears to be a successful reintroduction of the Lahontan cutthroat trout , which were fished to extinction in the Lake Tahoe area in the twenties and thirties. Sailing is challenging on
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#17328520256061078-595: The Undersea Voyager Project concluded that the ancient trees did not grow there during an ancient drought, but rather slid into the lake during one of the many seismic events that have occurred in the Tahoe Basin since it was formed. After the Tahoe Regional Planning Agency banned two-stroke outboard boat motors in the late 1990s, pollution from these engines was virtually eliminated. As
1127-539: The Fallen Leaf Lake Campground, operated by the Forest Service, and then past privately owned meadows . Two miles south of State Route 89, Angora Road provides access to Angora Lookout, a Forest Service fire lookout on the east side of the lake and approximately 1,000 feet (300 m) above the lake's surface, and to Angora Lakes Resort . It also connects to US 50 /SR 89 via Sawmill Road. Fallen Leaf Road continues south past privately owned homes following
1176-538: The LCT strain native to the watershed, began in 2006. This strain grows larger than any other LCT subspecies. Although the LCT suffer from heavy predation by lake trout, interbreeding with non-native rainbow trout ( Oncorhynchus mykiss ), and foraging competition with non-native kokanee salmon ( Oncorhynchus nerka ), their population is gradually increasing in the lake. Most homes that have lake front property have docks and/or boathouses , generally with an older ski boat or
1225-677: The LTBMU in 1973. The name of the Lake Tahoe Basin Management Unit reflects a unique sort of National Forest. The Lake Tahoe Basin Management Unit (LTBMU) is responsible for the conservation, preservation and restoration of the Lake Tahoe watershed ecosystem within National Forest Lands. Projects and programs also include habitat, fire management, and urban lot management. Additionally the LTBMU provides and maintains high quality recreational opportunities for millions of visitors and residents annually. Compared to other National Forest Lands
1274-421: The LTBMU is small, yet it is the Tahoe Basin's largest land manager, responsible for 78% of basin lands. As such the Forest Service has the largest single role in ecosystem and watershed management and protection. The LTBMU is a part of the National Forest System, yet is managed somewhat differently than other National Forests. Many common forest activities such as mining, grazing or timber harvesting are either not
1323-617: The Mount Tallac trail. Lahontan cutthroat trout ( Oncorhynchus clarkii henshawi ) is the only trout species native to Fallen Leaf Lake, Lake Tahoe and the Truckee River Basin but were extirpated by introduction of predatory non-native lake trout ( Salvelinus namaycush ), other competing non-native salmonids, and overfishing. Re-introduction into Fallen Leaf Lake of the Pilot Peak strain of Lahontan cutthroat trout (LCT), established as
1372-596: The bed is given by the Exner equation . This expression states that the rate of increase in bed elevation due to deposition is proportional to the amount of sediment that falls out of the flow. This equation is important in that changes in the power of the flow change the ability of the flow to carry sediment, and this is reflected in the patterns of erosion and deposition observed throughout a stream. This can be localized, and simply due to small obstacles; examples are scour holes behind boulders, where flow accelerates, and deposition on
1421-579: The body of water. Terrigenous material is often supplied by nearby rivers and streams or reworked marine sediment (e.g. sand ). In the mid-ocean, the exoskeletons of dead organisms are primarily responsible for sediment accumulation. Deposited sediments are the source of sedimentary rocks , which can contain fossils of the inhabitants of the body of water that were, upon death, covered by accumulating sediment. Lake bed sediments that have not solidified into rock can be used to determine past climatic conditions. The major areas for deposition of sediments in
1470-403: The bottom may be hidden in as little as 100 feet (30 m) offshore. The water quality is extremely good due to the lack of commercial development (including golf courses and their fertilizer -rich runoff), the universal use of sewers , and modern sediment retention techniques associated with new development. Visibility runs around 40–50 feet (10–15 m) under most conditions. The water
1519-411: The bottom of Fallen Leaf Lake, preserved for some 800 years by the cold water. Some scientists believe that these trees show evidence of a so-called " megadrought " occurring between the 9th and 12th centuries that eliminated or reduced the lake, allowing conifers to grow to maturity. Even older trees have been identified by dendrologists dating to between 18 and 35 centuries ago. A recent expedition by
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1568-417: The coastal regions of the ocean, the proportion of land, marine, and organic-derived sediment that characterizes the seafloor near sources of sediment output is altered. In addition, because the source of sediment (i.e., land, ocean, or organically) is often correlated with how coarse or fine sediment grain sizes that characterize an area are on average, grain size distribution of sediment will shift according to
1617-658: The core of later National Forest Lands in the Tahoe Basin. Three separate forests were developed out of the reserve, the Tahoe, Eldorado and Toiyabe National Forests. Each of these forests extended into the basin and managed separate sections. In 1973, the LTBMU was created from basin portions of the three existing National Forests, the Tahoe and Eldorado National Forests in California and the Toiyabe National Forest in Nevada, forming
1666-422: The edges and corners of particle are. Complex mathematical formulas have been devised for its precise measurement, but these are difficult to apply, and most geologists estimate roundness from comparison charts. Common descriptive terms range from very angular to angular to subangular to subrounded to rounded to very rounded, with increasing degree of roundness. Surface texture describes the small-scale features of
1715-510: The flow. In geography and geology , fluvial sediment processes or fluvial sediment transport are associated with rivers and streams and the deposits and landforms created by sediments. It can result in the formation of ripples and dunes , in fractal -shaped patterns of erosion, in complex patterns of natural river systems, and in the development of floodplains and the occurrence of flash floods . Sediment moved by water can be larger than sediment moved by air because water has both
1764-513: The glaciers receded from the Fallen Leaf basin, they left some dramatic rock formations including Cathedral Peak to the west, and the ridge upon which the Angora Lookout is located on the east (now forested). Cathedral Peak (8,200 feet (2,500 m)) might be better named Cathedral Ridge since, while it appears to be a solitary peak from the vantage point on the lake, it is really the beginning of
1813-539: The inside of meander bends. Erosion and deposition can also be regional; erosion can occur due to dam removal and base level fall. Deposition can occur due to dam emplacement that causes the river to pool and deposit its entire load, or due to base level rise. Seas, oceans, and lakes accumulate sediment over time. The sediment can consist of terrigenous material, which originates on land, but may be deposited in either terrestrial, marine, or lacustrine (lake) environments, or of sediments (often biological) originating in
1862-503: The lake due to the shifty and gusty winds. The prevailing winds can either be southerlies from Glen Alpine Valley, or northerlies from Lake Tahoe. Sailors must contend with occasionally strong gusts, and the water temperature is not amenable to capsizes. Families that have, or have had, residences at Fallen Leaf Lake: Lake Tahoe Basin Management Unit The Lake Tahoe Basin Management Unit
1911-477: The lakeshore. Emigrant Road connects to Fallen Leaf Road approximately three miles from SR 89, and provides access to houses above the lake on the eastern slope. There is little commercial development at the lake other than the tiny Fallen Leaf Marina and Store at the southern extremity of the lake. The road winds around the south end of the lake, past St. Francis of the Mountains, an Episcopalian chapel, and then across
1960-406: The long, intermediate, and short axis lengths of the particle. The form ψ l {\displaystyle \psi _{l}} varies from 1 for a perfectly spherical particle to very small values for a platelike or rodlike particle. An alternate measure was proposed by Sneed and Folk: which, again, varies from 0 to 1 with increasing sphericity. Roundness describes how sharp
2009-435: The marine environment include: One other depositional environment which is a mixture of fluvial and marine is the turbidite system, which is a major source of sediment to the deep sedimentary and abyssal basins as well as the deep oceanic trenches . Any depression in a marine environment where sediments accumulate over time is known as a sediment trap . The null point theory explains how sediment deposition undergoes
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2058-491: The relative input of land (typically fine), marine (typically coarse), and organically-derived (variable with age) sediment. These alterations in marine sediment characterize the amount of sediment suspended in the water column at any given time and sediment-related coral stress. In July 2020, marine biologists reported that aerobic microorganisms (mainly), in " quasi-suspended animation ", were found in organically-poor sediments, up to 101.5 million years old, 250 feet below
2107-473: The removal of native vegetation for the cultivation and harvesting of a single type of crop has left the soil unsupported. Many of these regions are near rivers and drainages. Loss of soil due to erosion removes useful farmland, adds to sediment loads, and can help transport anthropogenic fertilizers into the river system, which leads to eutrophication . The Sediment Delivery Ratio (SDR) is fraction of gross erosion (interill, rill, gully and stream erosion) that
2156-548: The science of forest and ecosystem management . The work of the Forest Service supports and is supported by many partners. Other federal, state and local agencies are working together in the effort to face challenges, conserve and restore natural and cultural resources, and enhance the recreational values of the Lake Tahoe Basin. In 1899 President William McKinley created the Lake Tahoe Forest Reserve, becoming
2205-454: The sheer face of Mount Tallac and north of Stanford Sierra Camp . The average depth of the lake is around 240 feet (72 m), and the bottom falls away rapidly as one moves away from the shorelines at the southern end. Due to the action of the glaciers that carved the lake, the northern end of the lake has a much more gradual depth change, and the bottom can be seen from the surface for a quarter-mile (400 m) offshore. Along other shores,
2254-401: The spring, melting snow causes a vigorous flow of cold water into the lake which gradually tapers off during the summer months until the creek flow is greatly reduced in late summer and the fall . Other much smaller creeks and streams feed the lake, including Cathedral Creek, but they are not nearly as important as Glen Alpine Creek. Taylor Creek is the only outflow, and it is controlled by
2303-445: The surface of the grain. Form (also called sphericity ) is determined by measuring the size of the particle on its major axes. William C. Krumbein proposed formulas for converting these numbers to a single measure of form, such as where D L {\displaystyle D_{L}} , D I {\displaystyle D_{I}} , and D S {\displaystyle D_{S}} are
2352-494: The use of a scanning electron microscope . Composition of sediment can be measured in terms of: This leads to an ambiguity in which clay can be used as both a size-range and a composition (see clay minerals ). Sediment is transported based on the strength of the flow that carries it and its own size, volume, density, and shape. Stronger flows will increase the lift and drag on the particle, causing it to rise, while larger or denser particles will be more likely to fall through
2401-538: The west side of the lake. While it runs to within about three-quarters of a mile (1.2 km) of Fallen Leaf Road, the two roads do not connect. Some of the homes on the west side of the lake have no road access and are accessed on foot or by boat. Fallen Leaf Lake is fed almost entirely by Glen Alpine Creek at the south end, which is in turn fed by several lakes in the Desolation Wilderness area including Gilmore Lake , Susie Lake, Heather Lake, and Grass Lake. In
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