Lost streams of Idaho

Course

The Big Lost River is about 135 mi long and has two main tributary forks, the North Fork Big Lost River and the East Fork Big Lost River. The river originates in the Pioneer Mountains in Salmon-Challis National Forest, flows northeast then turns southeast, with the Lost River Range to the east separating the Big Lost River Valley from the Little Lost River Valley. A dam impounds the river and creates Mackay Reservoir. Near Arco the river enters the Snake River Plain, curves east and then northeast and enters the depression where the water flows into the ground, called Big Lost River Sinks. Near the sinks there is a dry distributary called the Dry Channel Big Lost River.

The Little Lost River is about 49 mi long. It flows southeast between the Lost River Range to the west and the Lemhi Range to the east. It enters the Snake River Plain north of the sinks and flows into them at locations called Little Lost River Sinks.

The sinks and the lower courses of both rivers are within the land of the Idaho National Laboratory, northeast of Craters of the Moon. Water from both rivers emerges about 100 mi away at Thousand Springs near Hagerman and other springs downstream of Twin Falls. Due to irrigation using the aquifer's water, most of the rivers' water is pumped out of the ground, used to irrigate crops, and returned to the ground as irrigation drainage, where it eventually emerges at the springs and joins the Snake River.

Basin and discharge

The Big Lost River's drainage basin is approximately 1400 sqmi in area Its mean annual discharge, as measured by USGS gage 13132500 (Big Lost River near Arco), is 91.7 cuft/s, with a maximum daily recorded flow of 1840 cuft/s, and a minimum of zero flow.

The Little Lost River's drainage basin is approximately 971 sqmi in area Its mean annual discharge, as measured by USGS gage 13118700 (Little Lost River below Wet Creek, near Howe, Idaho), is 65 cuft/s, with a maximum daily recorded flow of 486 cuft/s, and a minimum of 3 cuft/s.

References

• "Idaho Atlas and Gazetteer". 5th ed. DeLorme, 2002.
• Big Lost River, The Columbia Gazetteer of North America.
• Little Lost River, The Columbia Gazetteer of North America.

References

1. U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. [http://viewer.nationalmap.gov/viewer/ The National Map] {{webarchive. link. (2012-03-29 , accessed May 4, 2011)
2. [http://www.nwcouncil.org/fw/subbasinplanning/uppersnake/plan/Assessment/1IntroOverview.pdf Upper Snake, Headwaters, Closed Basin Subbasins Plan Plan] {{Webarchive. link. (2012-02-13 , Northwest Power and Conservation Council)
3. [https://pubs.usgs.gov/wdr/2005/wdr-id-05-1/pdf/ID05v1-11.pdf Snake River basin between Mud Lake and King Hill (includes Lost, Wood, Malad River basins)], Water Resources Data, Idaho, 2005