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34-509: Coldwater Lake may refer to: Coldwater Lake (Washington) , a lake formed in the 1980 eruption of Mount St. Helens Coldwater Lake (Michigan) , a lake in south-central Michigan Coldwater Lake State Park , an undeveloped public recreation area on the shore of the lake in Michigan Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

68-402: A fuse plug . If present, the fuse plug is designed to wash out in case of a large flood, greater than the discharge capacity of the spillway gates. Although many months may be needed for construction crews to restore the fuse plug and channel after such an operation, the total damage and cost to repair is less than if the main water-retaining structures had been overtopped. The fuse plug concept

102-443: A baffle of concrete blocks but usually have a "flip lip" and/or dissipator basin, which creates a hydraulic jump , protecting the toe of the dam from erosion. Stepped channels and spillways have been used for over 3,000 years. Despite being superseded by more modern engineering techniques such as hydraulic jumps in the mid twentieth century, since around 1985 interest in stepped spillways and chutes has been renewed, partly due to

136-463: A few dams lack overflow spillways and rely entirely on bottom outlets. The two main types of spillways are controlled and uncontrolled. A controlled spillway has mechanical structures or gates to regulate the rate of flow. This design allows nearly the full height of the dam to be used for water storage year-round, and flood waters can be released as required by opening one or more gates. An uncontrolled spillway, in contrast, does not have gates; when

170-565: A plunge pool, or two ski jumps can direct their water discharges to collide with one another. Third, a stilling basin at the terminus of a spillway serves to further dissipate energy and prevent erosion. They are usually filled with a relatively shallow depth of water and sometimes lined with concrete. A number of velocity-reducing components can be incorporated into their design to include chute blocks, baffle blocks, wing walls, surface boils, or end sills. Spillway gates may operate suddenly without warning, under remote control. Trespassers within

204-471: A spillway only during flood periods, when the reservoir has reached its capacity and water continues entering faster than it can be released. In contrast, an intake tower is a structure used to control water release on a routine basis for purposes such as water supply and hydroelectricity generation. A spillway is located at the top of the reservoir pool. Dams may also have bottom outlets with valves or gates which may be operated to release flood flow, and

238-495: A volume of 67,300 acre-feet (83,000,000 m ). In May 1985 a tunnel was excavated to connect Spirit Lake to South Coldwater Creek. The eruption had blocked the outlet of Spirit Lake causing it to rise to dangerous levels. The tunnel allowed excess water from Spirit Lake to drain into Coldwater Lake, and from there into the Toutle River. The landslide dam forming Coldwater Lake was closely monitored until 1998, when its stability

272-460: Is designed like an inverted bell , where water can enter around the entire perimeter. These uncontrolled spillways are also called morning glory (after the flower ), or glory hole spillways. In areas where the surface of the reservoir may freeze, this type of spillway is normally fitted with ice-breaking arrangements to prevent the spillway from becoming ice-bound. Some bell-mouth spillways are gate-controlled. The highest morning glory spillway in

306-443: Is set by dam safety guidelines, based on the size of the structure and the potential loss of human life or property downstream. The United States Army Corps of Engineers bases their requirements on the probable maximum flood (PMF) and the probable maximum precipitation (PMP). The PMP is the largest precipitation thought to be physically possible in the upstream watershed. Dams of lower hazard may be allowed to have an IDF less than

340-604: Is used where building a spillway with the required capacity would be costly. A chute spillway is a common and basic design that transfers excess water from behind the dam down a smooth decline into the river below. These are usually designed following an ogee curve . Most often, they are lined on the bottom and sides with concrete to protect the dam and topography. They may have a controlling device and some are thinner and multiply-lined if space and funding are tight. In addition, they are not always intended to dissipate energy like stepped spillways. Chute spillways can be ingrained with

374-461: The North Fork of the Toutle River, burying the whole valley up to 600 feet (180 m) deep. The lahar backed up Coldwater Creek for more than a mile (1.6 km), damming the creek and its tributary South Fork Coldwater Creek to a height of 180 feet (55 m). Over the next few months, almost 100,000 acre-feet (120,000,000 m ) of water collected to form a lake 5 miles (8 km) in length. At

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408-460: The PMF. As water passes over a spillway and down the chute, potential energy converts into increasing kinetic energy . Failure to dissipate the water's energy can lead to scouring and erosion at the dam's toe (base). This can cause spillway damage and undermine the dam's stability. To put this energy in perspective, the spillways at Tarbela Dam could, at full capacity, produce 40,000 MW; about 10 times

442-513: The blast zone. The lake is now part of Mount St. Helens National Volcanic Monument , designated in 1982. Washington State Route 504 (the Spirit Lake Highway) provides access from Interstate 5 at Castle Rock . Coldwater Ridge Visitor Center, located on the cliffs west of the lake, provides a panoramic view of the valley; on weekends a Science and Learning Center is open to the public here. The Coldwater Lake Recreation Area, located on

476-407: The capacity of its power plant. The energy can be dissipated by addressing one or more parts of a spillway's design. First, on the spillway surface itself by a series of steps along the spillway (see stepped spillway ). Second, at the base of a spillway, a flip bucket can create a hydraulic jump and deflect water upwards. A ski jump can direct water horizontally and eventually down into

510-414: The difference in height between the intake and the outlet to create the pressure difference required to remove excess water. Siphons require priming to remove air in the bend for them to function, and most siphon spillways are designed to use water to automatically prime the siphon. One such design is the volute siphon, which employs volutes or fins on a funnel to form water into a vortex that draws air out of

544-423: The flood is sometimes expressed as a return period . A 100-year recurrence interval is the flood magnitude expected to be exceeded on the average of once in 100 years. This parameter may be expressed as an exceedance frequency with a 1% chance of being exceeded in any given year. The volume of water expected during the design flood is obtained by hydrologic calculations of the upstream watershed. The return period

578-494: The lake but continues to manage it as a trout fishery. The daily catch limit is one fish, minimum length 18 inches (46 cm). Spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee , typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels . Spillways ensure that water does not damage parts of

612-639: The lake by the eruption. The Lakes Trail runs along the western shore and allows access to the Mount Margaret Backcountry beyond the lake. The lake has had resident rainbow trout and cutthroat trout since the Washington State Department of Fish and Wildlife (DFW) stocked it in the 1980s. Pre-1980 fish populations in Coldwater Creek and the Toutle River were wiped out by the eruption of Mount St. Helens. The DFW no longer stocks

646-428: The lake. Several smaller lakes or glacial tarns are part of the watershed; the named ones are Heart Lake and Snow Lake, which both flow into Coldwater Creek before entering Coldwater Lake. Mount Whittier , the highest point in the basin at 5,883-foot (1,793 m), sits at the head of the Coldwater Creek valley. The eruption of Mount St. Helens on May 18, 1980, created a lahar or debris avalanche that rushed down

680-428: The rate the lake was filling, it was anticipated to overtop the landslide dam by late 1981 or 1982. Because the material forming the dam consisted of soft volcanic debris and ash, it would erode quickly if overtopped, causing serious flooding downstream. In early 1981, the U.S. Army Corps of Engineers excavated a spillway and outlet channel for the lake, stabilizing it at 2,503 feet (763 m) above sea level with

714-411: The reservoir is controlled by the mechanical gates. In this case, the dam is not designed to function with water flowing over the top if it, either due to the materials used for its construction or conditions directly downstream. If inflow to the reservoir exceeds the gate's capacity, an artificial channel called an auxiliary or emergency spillway will convey water. Often, that is intentionally blocked by

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748-456: The river downstream. One parameter of spillway design is the largest flood it is designed to handle. The structures must safely withstand the appropriate spillway design flood (SDF), sometimes called the inflow design flood (IDF). The magnitude of the SDF may be set by dam safety guidelines, based on the size of the structure and the potential loss of human life or property downstream. The magnitude of

782-403: The same manner as Coldwater Lake during the 1980 eruption, is located about 3 miles (4.8 km) to the south. The area is about 50 miles (80 km) northeast of Longview and 100 miles (160 km) north of Portland, Oregon . Coldwater is a ribbon lake , occupying the trough of a glacial valley. The surrounding ridges rise dramatically to heights of more than 1,000 feet (300 m) above

816-461: The south end of the lake, is available for day use only as the area is located within the restricted zone of the National Monument. The recreation area includes a picnic area, restrooms and boat ramp (non-motorized watercraft only). The 0.6-mile (1 km) Birth of a Lake Trail is a boardwalk trail accessible from the recreation area, and includes interpretive displays discussing the formation of

850-414: The spillway are at high risk of drowning. Spillways are usually fenced and equipped with locked gates to prevent casual trespassing within the structure. Warning signs, sirens, and other measures may be in place to warn users of the downstream area of sudden release of water. Operating protocols may require "cracking" a gate to release a small amount of water to warn persons downstream. The sudden closure of

884-539: The structure not designed to convey water. Spillways can include floodgates and fuse plugs to regulate water flow and reservoir level. Such features enable a spillway to regulate downstream flow—by releasing water in a controlled manner before the reservoir is full, operators can prevent an unacceptably large release later. Other uses of the term "spillway" include bypasses of dams and outlets of channels used during high water, and outlet channels carved through natural dams such as moraines . Water normally flows over

918-424: The system. The priming happens automatically when the water level rises above the inlets. The ogee crest over-tops a dam, a side channel wraps around the topography of a dam, and a labyrinth uses a zig-zag design to increase the sill length for a thinner design and increased discharge. A drop inlet resembles an intake for a hydroelectric power plant, and transfers water from behind the dam directly through tunnels to

952-521: The title Coldwater Lake . 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=Coldwater_Lake&oldid=844458077 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Coldwater Lake (Washington) The lake runs from northeast to southwest, with

986-474: The use of new construction materials (e.g. roller-compacted concrete , gabions ) and design techniques (e.g. embankment overtopping protection). The steps produce considerable energy dissipation along the chute and reduce the size of the required downstream energy dissipation basin. Research is still active on the topic, with newer developments on embankment dam overflow protection systems, converging spillways and small weir design. A bell-mouth spillway

1020-474: The water rises above the lip or crest of the spillway, it begins to be released from the reservoir. The rate of discharge is controlled only by the height of water above the reservoir's spillway. The fraction of storage volume in the reservoir above the spillway crest can only be used for the temporary storage of floodwater; it cannot be used as water supply storage because it sits higher than the dam can retain it. In an intermediate type, normal level regulation of

1054-547: The water. The length of the lake is about 5 miles (8.0 km) while the maximum width is no more than half a mile (0.8 km). The water surface is 2,503 feet (763 m) above sea level and the surface area is 773 acres (313 ha). The total watershed of Coldwater Lake is about 16.6 sq mi (43 km ). Coldwater Creek drains 5.4 square miles (14 km ) or 33% of the total, South Fork Coldwater Creek drains 6.3 square miles (16 km ) or 38%, and another 4.9 square miles (13 km ) or 30% drains directly into

Coldwater Lake - Misplaced Pages Continue

1088-820: The west end in Cowlitz County and the east end in Skamania County. The portion of the lake in Skamania County is part of Gifford Pinchot National Forest . Coldwater Creek drains the lake on its southwest end and flows into the North Fork of the Toutle River , a tributary of the Cowlitz River , in turn a tributary of the Columbia River . Coldwater Lake is located 8 miles (13 km) north of Mount St. Helens , 5 miles (8 km) west of Spirit Lake. Castle Lake , formed in

1122-669: The world is at Hungry Horse Dam in Montana, U.S., and is controlled by a 64-by-12-foot (19.5 by 3.7 m) ring gate. The bell-mouth spillway in Covão dos Conchos reservoir in Portugal is constructed to look like a natural formation. The largest bell-mouth spillway is in Geehi Dam , in New South Wales, Australia, measuring 105 ft (32 m) in diameter at the lake's surface. A siphon uses

1156-458: Was no longer deemed a serious concern. The lake has since been shrinking slowly due to erosion of the approximately 17-square-mile (44 km ) watershed, which was largely stripped of vegetation during the 1980 eruption. However, the area has recovered significantly in the intervening decades with second-growth forest returning. Several deltas have formed around the lake, the largest formed at South Coldwater Creek, whose valley sits closest to

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