Blue Earth River
| Blue Earth River | ||
 Map of the catchment area |
||
| Data | ||
| Water code | US : 640285 | |
| location | Minnesota (USA) | |
| River system | Mississippi River | |
| Drain over | Minnesota River → Mississippi → Gulf of Mexico | |
| confluence | from West Branch and Middle Branch at Elmore in Faribault County 43 ° 34 ′ 20 ″ N , 94 ° 6 ′ 11 ″ W |
|
| Source height | 328 m | |
| muzzle |
Minnesota River at Mankato Coordinates: 44 ° 9 '51 " N , 94 ° 2' 13" W 44 ° 9 '51 " N , 94 ° 2' 13" W |
|
| Mouth height | 239 m | |
| Height difference | 89 m | |
| Bottom slope | 0.51 ‰ | |
| length | 174 km | |
| Catchment area | 9029 km² | |
| Drain |
MQ |
30 m³ / s |
| Left tributaries | Watonwan River | |
| Right tributaries | East Branch Blue Earth River, Le Sueur River |
|
| Communities | Winnebago , Vernon Center | |
 Blue Earth River near Vernon Center, Minnesota |
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 Blue Earth River at Rapidan Dam in Blue Earth County (2007) |
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 The Blue Earth River near the USGS level (2007) |
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| East Branch Blue Earth River | ||
| Water code | US : 643049 | |
| location | Minnesota (USA) | |
| source | in the SW of Freeborn County 43 ° 33 ′ 13 ″ N , 93 ° 37 ′ 19 ″ W |
|
| muzzle | at Blue Earth in the Blue Earth River 43 ° 39 ′ 1 ″ N , 94 ° 6 ′ 16 ″ W |
|
| Mouth height |
316 m
|
|
| length | 90 km | |
| Middle Branch Blue Earth River | ||
| Water code | US : 459026 | |
| location | Iowa , Minnesota (USA) | |
| source | in the NW of Winnebago County 43 ° 27 ′ 30 ″ N , 93 ° 48 ′ 4 ″ W |
|
| Union | with West Branch Blue Earth River to Blue Earth River 43 ° 34 ′ 19 ″ N , 94 ° 6 ′ 12 ″ W |
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| Mouth height |
326 m
|
|
| length | 27 km | |
| West Branch Blue Earth River | ||
| Water code | US : 462810 | |
| location | Iowa , Minnesota (USA) | |
| source | in the north of Kossuth County 43 ° 24 ′ 10 ″ N , 94 ° 17 ′ 7 ″ W |
|
| Union | with Middle Branch Blue Earth River to Blue Earth River 43 ° 34 ′ 20 ″ N , 94 ° 6 ′ 13 ″ W |
|
| Mouth height |
326 m
|
|
| length | 24 km | |
The Blue Earth River is a 174 km long river in the southern US state of Minnesota .
Two of its headwaters flow a short distance in northern Iowa . In Mankato it flows into the Minnesota River and is thus an indirect tributary of the Mississippi River . The river is the largest tributary of the Minnesota River in terms of water volume and contributes 46% of the water volume of Minnesota at the confluence of the two bodies of water. The catchment area of the Blue Earth River covers 9029 km² in an agricultural region. Nine tenths of that are in Minnesota.
history
The river is named after the earlier occurrences of blue-green clay on its banks, which are no longer visible today. The name of the river in the Dakota language is Makato Osa Watapa , "the river where the blue earth is collected". The French explorer Pierre-Charles Le Sueur founded Fort L'Huillier near the estuary in 1700 . The purpose of the establishment was to mine the clay, either on the assumption that it contained copper or to ensure that its superiors would finance its fur trading activities. The fort was abandoned the following year after an attack by the Fox Indians . During the 19th century, the geographer Joseph Nicolas Nicollet found pits in which the clay was extracted by the local Indians . They used it for body painting. He found no traces of Le Sueur's mines or the fort.
geography
The course of the Blue Earth River begins at the junction of its western and middle arms, about eight kilometers north of Elmore in the southwest of Faribault County . The Middle Branch Blue Earth River is 17 miles long and is sometimes referred to as the main arm. It rises in the northwest of Winnebago County , about eleven kilometers east of Rake . Its course travels westward into Kossuth County and then northward into Faribault County. The source of the 15 miles long West Branch Blue Earth River is located near Swea City in northern Kossuth County. It runs in a northeasterly direction. These two source rivers are largely canalized . From the point of union the Blue Earth River flows in a winding course through the east of Faribault County into Blue Earth County . At Blue Earth flows the longest headwaters, the approximately 90 km long East Branch Blue Earth River , which rises in southwest Freeborn County and flows westward through Faribault County.
The Blue Earth River passes the cities of Winnebago and Vernon Center before reaching Mankato, where it joins the Minnesota River from the south. Rapidan Dam was built in 1910 for the purpose of generating energy from hydropower . It dams the river about 19 km above its mouth. After completion, the reservoir filled with sediments. The power generation was later stopped, but resumed in 1984.
The two largest tributaries of the Blue Earth River are the Le Sueur River , which flows in five kilometers from the mouth of the river, and the Watonwan River , whose mouth is 26 km above the Minnesota River. These two rivers drain 31% and 24% of the catchment area of the Blue Earth River. One of the tributaries on the upper reaches is the Elm Creek , near Winnebago in the northeast of Faribault County. Its 121 km long watercourse begins in the northeast of Jackson County . It flows through Martin County in an easterly direction .
According to the Minnesota Pollution Control Agency, about 84% of the catchment area is used for agriculture , mainly for growing corn and soybeans . The river is one of the most polluted rivers in Minnesota. Sedimentation , bacteria , nitrates , phosphorus , mercury , polychlorinated biphenyls (PCBs) and pesticides , which are mainly caused by washing off the land surface of the catchment area, reach particularly high values . In addition, there is the discharge of faeces through human settlements and livestock use. Due to outdated water purification systems and leaky septic tanks , this pollution has reached a level that makes the state government judge that the river is unsafe for swimming.
The Blue Earth River mostly flows through a ground moraine that lies on the bottom of a former glacial lake. The lower reaches in the north was originally overgrown by a hardwood forest. Most of this area has been cleared for agricultural use. Below the Rapidan Dam, the river flows through a wooded canyon in the valley of the Minnesota River. This section is popular with canoeists .
Hydrology
The United States Geological Survey operates a gauge on the Blue Earth River below Rapidan Dam in Rapidan Township . It lies between the confluences of the Watonwan River and the Le Sueur Rivers, 19 km above the mouth of the river in the Mississippi. The mean annual runoff of the river at this level averaged 30 m³ / s between 1909 and 2005 . The highest recorded flow rate during this time was 1220 m³ / s and was recorded on April 9, 1965, the lowest value was measured on October 12, 1955 with 0.2 m³ / s.
Individual evidence
- ↑ a b Blue Earth River in the Geographic Names Information System of the United States Geological Survey
- ↑ a b c Watersheds of the Minnesota River Basin. . Minnesota Pollution Control Agency. S. Minnesota River Basin: Blue Earth, Watonwan, and Le Sueur River Watersheds . December 1, 2005. Archived from the original on February 5, 2007. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved January 15, 2008.
- ^ Warren Upham : Minnesota Place Names, A Geographical Encyclopedia, 3rd Edition . Minnesota Historical Society, Saint Paul, Minnesota 2001, ISBN 0-87351-396-7 , pp. 65.
- ↑ a b c Thomas F. Waters: The Blue Earth: Fool's Copper . In: The Streams and Rivers of Minnesota . University of Minnesota Press , Minneapolis 2006, ISBN 0-8166-0960-8 , pp. 278-287.
- ↑ a b c National Assessment Database: Assessment Data for the State of Minnesota in 2004. Year . United States Environmental Protection Agency . S. Blue Earth Watershed . Archived from the original on July 7, 2007. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved January 14, 2008.
- ↑ Middle Branch Blue Earth River in the Geographic Names Information System of the United States Geological Survey
- ↑ West Branch Blue Earth River in the Geographic Names Information System of the United States Geological Survey
- ^ East Branch Blue Earth River in the Geographic Names Information System of the United States Geological Survey
- ^ A b Minnesota Atlas & Gazetteer . DeLorme , Yarmouth, Me. 1994, ISBN 0-89933-222-6 , pp. 21-23, 32.
- ^ Iowa Atlas & Gazetteer . DeLorme , Yarmouth, Me. 1998, ISBN 0-89933-214-5 , pp. 18-19.
- ^ A b G. B. Mitton, KG Guttormson, GW Stratton, ES Wakeman: Water Resources Data in Minnesota, Water Year 2005 Annual Report. . United States Geological Survey . S. Blue Earth River near Rapidan, MN (PDF; 141 kB). Retrieved January 15, 2008.
- ^ Elm Creek in the Geographic Names Information System of the United States Geological Survey
- ^ Mark Steil: Blue Earth River heavily polluted , Minnesota Public Radio . June 9, 2005. Retrieved January 14, 2007.
