CNRFC - Hydrology - Observed River/Reservoir Conditions

WEST WALKER RIVER - HWY 395 BELOW LITTLE WALKER (WWBC1)

Latitude: 38.38º N	Longitude: 119.45º W	Elevation: 6591 Feet
Location: Mono County in California		River Group: Eastern Sierra

Monitor Stage: 5.5 Feet

Flood Stage: 6.0 Feet

Observed Data Credit
	Raw streamflow data is provided by the US Geological Survey (USGS). View USGS Data for this station location.

Historical Stage/Flow Data
Water Year	Peak Discharge (cfs)	Stage (feet)	Date
Most Recent 5 Years
2015	746	3.50	Jun 11, 2015
2014	972	3.79	May 26, 2014
2013	1,180	4.07	May 13, 2013
2012	972	3.77	Apr 23, 2012
2011	4,040	6.66	Jun 24, 2011
Historical High Stage/Flow Events (Period of Record - Apr 1938 to Present)
1997	12,300	10.11	Jan 02, 1997
1951	6,220	8.10	Nov 20, 1950
1938	5,800	--	Dec 11, 1937

Location Photographs
Upstream Photo	Gage House Photo	Downstream Photo

ESRI™ Locator Map

Official 7 Day National Weather Service Forecast (CAZ073)

Tonight: Clear. Lows 40 to 50. West winds 10 to 15 mph with gusts up to 30 mph in the evening becoming light.

Wednesday: Sunny in the morning, then partly cloudy with isolated showers and thunderstorms in the afternoon. Highs 84 to 94. Light winds becoming south up to 10 mph in the afternoon.

Wednesday Night: Partly cloudy with isolated showers and thunderstorms in the evening, then clear after midnight. Lows 42 to 52. West winds around 10 mph in the evening becoming light.

Thursday: Sunny in the morning, then partly cloudy with isolated showers and thunderstorms in the afternoon. Highs 84 to 94. Light winds becoming west around 10 mph in the afternoon.

Thursday Night: Partly cloudy with isolated showers and thunderstorms in the evening, then clear after midnight. Lows 44 to 54. West winds 10 to 15 mph in the evening becoming light.

Friday: Mostly sunny with a slight chance of showers and thunderstorms. Highs 85 to 95.

Friday Night: Partly cloudy with a slight chance of showers and thunderstorms. Lows 45 to 55.

Saturday through Monday: Partly cloudy with a slight chance of showers and thunderstorms. Highs 85 to 95. Lows 45 to 55.

Monday Night and Tuesday: Partly cloudy with a slight chance of showers and thunderstorms. Lows 44 to 54. Highs 84 to 94.

Impacts - E19 Information
5.5 Feet	Monitoring stage. No flooding. Max diversion to Topaz ~1300 cfs, rest goes downstream to Smith Valley. If Topaz is releasing...flow at Wellington will be Topaz release plus amount going down West Walker below diversion. Reach: W Walker River Canyon; lower Antelope Valley from W Walker River mouth to Topaz Lake including Walker/Coleville/Topaz; Smith Valley including Smith and Wellington; Mason Valley including Yerington. Approximately 2400 cfs.
6.0 Feet	Flood Stage. Some minor flooding of lowlands...pastures and rural roads. Maximum diversion to Topaz Lake is about 1300 cfs...remainder goes down the West Walker to Smith Valley/Wellington. If Topaz is releasing...flow at Wellington will be Topaz release plus amount going the West Walker below the Topaz diversion. Approximately 3000 cfs.
6.6 Feet	Minor to moderate flooding of lowlands...pastures and some rural roads along river from Walker to Topaz Lake. Moderate flooding on the lower West Walker (Smith Valley/Wellington) and mainstem Walker (Mason Valley/Yerington). Some sandbagging of structures likely in the Mason Valley/Yerington area. Approximately 3800 cfs with a 1 in 10 chance of occurring any given year.
7.0 Feet	Significant flooding of lowlands, agricultural land, yards, basements, rural roads. Flooding of structures limited in Antelope and Smith Valleys, although sandbagging necessary. Structure flooding significant in Mason Valley/Yerington on mainstem with much sandbagging. Approximately 4500 cfs with a 1 in 15 chance of occurring any given year. In July 1995, several homes and businesses flooded in the Smith/Mason Valleys, thousands of acres of farmland flooded, and levees overtopped.
7.3 Feet	Major flooding through reach and in Mason Valley and Yerington. Many buildings, roads flooded/washed out, major damage to agricultural lands, much sandbagging. Transportation affected. Severe damage to Highway 395 in W Walker Canyon. Approximately 5000 cfs with a 1 in 20 chance of occurring any given year.
7.9 Feet	Flooding near disaster levels through reach and Mason Valley/Yerington. Numerous structures flooded, roads washed out, many sections of Highway 395 destroyed in W Walker Canyon. Major damage to agricultural land due to erosion and destroyed facilities (diversion dams, headgates, canals, levees). Approximately 6100 cfs with a 1 in 35 chance of occurring any given year.
8.25 Feet	Flood disaster along entire reach...from W Walker River Canyon to Smith/Mason valleys. Widespread flood damage to roads...bridges...homes and structures along river. Severe damage to Highway 395 in Walker Canyon...and NV state route 208 in Smith Valley/Wilson Canyon. These highways likely closed. Approximately 6800 cfs with a 1 in 50 chance of occurring any given year. Historically this flow has been reached or exceeded only twice...December 1937 and January 1997.
8.8 Feet	Flood disaster from Walker River Canyon to Antelope Valley/Topaz Lake...Smith Valley/Wellington and Mason Valley/Yerington. Widespread flood damage to roads...bridges...homes and structures along river. Severe damage to Highway 395 in W Walker River Canyon and NV Highway 208 in Smith Valley/Wilson Canyon. These highways probably closed. Approximately 8200 cfs with a 1 in 100 chance of occurring any given year. Historically this flow has been exceeded only once...January 1997.
9.5 Feet	Near record flooding. Area cut off as most transportation routes into area destroyed/flooded. Massive destruction of infrastructure/economy including power, roads, business, water, homes, etc. Approximately 10,000 cfs with a 1 in 200 chance of occuring in any given year.
10.25 Feet	Flood of record. Highway 395 in W Walker River Canyon closed for months. Massive destruction to infrastructure and economy including transportation, power, water, homes, businesses, etc. Area isolated. At this stage, 6.5 mile stretch of Highway 395 completely scoured with debris from canyon deposited in the town of Walker. Approximately 12,500 cfs with a 1 in 500 chance of occurring in any given year.
10.5 Feet	Incredible flood disaster previously unknown. Greater than 13,000 cfs.

Product Disclaimer

This river graphic is not intended to serve as a substitute for official flood watches, warnings, advisories, or statements issued by the NWS Reno Weather Forecast Office. Observations are preliminary and subject to change. River levels identified as "forecast" should be consistent with those contained in official NWS products. River levels identified as "guidance" have significant uncertainty due to future weather or reservoir regulation and are provided for planning purposes only.

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