• Ron Abramovich, Hydrologist, Water Supply Specialist• USDA Natural Resources Conservation Service (NRCS)• Snow Survey Office Boise Idaho • http://www.id.nrcs.usda.gov/snow/

Idaho's Climate and Water Resource Forecast for the 2008 Water Year

Sponsored by: The Climatic Impacts Group at the University of Washington and the Idaho

Department of Water Resources

The Good, The Bad, The Ugly…. What Happened?????

News Releases - 2007

Date News Release Title

January 8, 2007 Idaho Water Supply Outlook is Promising

February 6, 2007 Dry Conditions Put Damper on Idaho’s Water Supply Outlook

March 8, 2007 Recent Precipitation Rejuvenates Idaho's Water Supply

April 6, 2007 Idaho's Water Supply Outlook is Disappointing

June 5, 2007 Winter Too Short, Summer Too Early

The Good, The Bad, The Ugly…. What Happened?????

News Releases - 2007

Date News Release Title

January 8, 2007 Idaho Water Supply Outlook is Promising

February 6, 2007 Dry Conditions Put Damper on Idaho’s Water Supply Outlook

March 8, 2007 Recent Precipitation Rejuvenates Idaho's Water Supply

April 6, 2007 Idaho's Water Supply Outlook is Disappointing

June 5, 2007 Winter Too Short, Summer Too Early

The Good, The Bad, The Ugly…. What Happened?????

News Releases - 2007

Date News Release Title

January 8, 2007 Idaho Water Supply Outlook is Promising

February 6, 2007 Dry Conditions Put Damper on Idaho’s Water Supply Outlook

March 8, 2007 Recent Precipitation Rejuvenates Idaho's Water Supply

April 6, 2007 Idaho's Water Supply Outlook is Disappointing

June 5, 2007 Winter Too Short, Summer Too Early

The Good, The Bad, The Ugly…. What Happened?????

News Releases - 2007

Date News Release Title

January 8, 2007 Idaho Water Supply Outlook is Promising

February 6, 2007 Dry Conditions Put Damper on Idaho’s Water Supply Outlook

March 8, 2007 Recent Precipitation Rejuvenates Idaho's Water Supply

April 6, 2007 Idaho's Water Supply Outlook is Disappointing

May 6, 2007 Idaho's Ever Changing Water Supply

June 5, 2007 Winter Too Short, Summer Too Early

The Good, The Bad, The Ugly…. What Happened?????

Bear Mountain SNOTEL Site, elevation 5,400 feet, 24-hour precipitation Nov 6-7, 2006 8am to 8am was 9.4 inches. Amount received midnight to midnight on Nov 6 was 8.4 inches. In addition, the snow pillow had 2.9 inches of snow water on Nov 4 of which all melted by Nov 8. Snow water melt on Nov 6 was 1.4 inches for a combined snow and rain runoff total of 10.8 inches. Previous 24-hour precipitation record was 6.9 inches on Nov 10, 1990 with 2.6 inches of melt occurring over several days.

2007 Snow and Precipitation

2007 Snow and Precipitation

2007 Snow and Precipitation

2007 Snow and Precipitation

May – September 2007 Idaho SNOTEL Precipitation

Mud Flat, Owyhee Basin2nd driest May-Sep in 26 years2.0” of Precipitation, 44% Avg

Garfield, Little Wood Basin4th driest May-Sep in 26 years3.7” of Precipitation, 50% Avg

Atlanta, Boise Basin3rd driest May-Sep in 26 years3.7” of Precipitation, 45% Avg

Secesh, Payette/Salmon Basin4th driest May-Sep in 26 years6.8” of Precipitation, 67% Avg

Island Park, Henrys Fork Basin2nd driest May-Sep in 26 years4.2” of Precipitation, 44% Avg

Shanghi, N.F. Clearwater Basin2nd driest May-Sep in 26 years6.9” of Precipitation, 51% Avg

Mosquito, Couer D’ Alene BasinDRIEST May-Sep in 26 years4.5” of Precipitation, 39% Avg

Schweitzer Basin, Pend Oreille Basin2nd driest May-Sep in 26 years7.5” of Precipitation, 61% Avg

March – July 2007 SNOTEL Precipitation Exceedances

Black Bear, MTPrecipitation = 8.5”> 99% exceedance

Meadow Lake, IDPrecipitation = 11.9”80-90% exceedance

Island Park, IDPrecipitation = 4.1”99% exceedance

Schweitzer Saddle, IDPrecipitation = 13.3”90-95% exceedance

Big Creek Summit, IDPrecipitation = 7.3”

95-99% exceedance

Hilts Creek, IDPrecipitation = 5.7”

80-90% exceedance

Hot March

2007 Streamflow Forecasts

What Happened?????

Water Year Precip is Avg

0

50

100

150

200

250

Per

cen

t o

f A

vera

ge

Oct Dec Feb Apr Jun Aug

Mountain PrecipitationCLEARWATER RIVER BASIN

Monthly Year-to-date

Mountain Snowpack (inches)CLEARWATER RIVER BASIN

0

10

20

30

40

50

60

70

Jan Feb Mar Apr May Jun

Wat

er C

on

ten

t In

ches

.

Current Average

Maximum Minimum

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Buffalo Creek is usually one of the streams that peaks the latest from snowmelt in the upper Snake River headwaters. Streamflow record starts in 1966.

Date and CFS Peak Flow in 2007:

May 14 1860 cfs peak

May 20 1850 cfs peak

June 6 1860 cfs peak

Peak flow of 1860 cfs in 2007 nearly tied the previous lowest peak of 1850 cfs in 1992 AND earliest peak recorded was May 14, 1994, 2920 cfs.

2007 had two peak of 1860 on May 20 and 3rd peak of 1860 on June 6.

Highest cfs peak --- 6540 cfs on June 9, 1981

Latest cfs peak --- July 10 1983, 3940 cfs

The 2nd peak flow in 2007 had less volume associated with it when compared to first peak. Third peak of 1650 cfs occurred on June 17. All are based on provisional data.

Snowpack Needed for 2008 Season

Analysis is Based on September 30, 2007 Reservoir Storage

•Current Storage is Projected for March 31, 2008 Estimated Levels

•Required Streamflow Needed to Meet Irrigation Agriculture Demand Based on SWSIs (Surface Water Supply Index)

•Snowpack Needed for 2008 is Determined by Looking at Years When We had a Good Snowpack and Worst Case Scenarios Leading into or during the Snowmelt Runoff Season:

• Low Soil Moisture

• Low Groundwater Levels

• Dry Spring

• Cumulative Drought Effects

• 1989 is Good Example of Bad Runoff Year – snowpack was about average, but runoff was below to much below average due to dry spring and consecutive of drought years.

2007 Castle RockFire Location

SNOTEL site

Miles

0 2 4 8

Level

North

East

South

West

ASPECT

2007 Castle Rock FireBurned Area by Aspect

Acres Burned

Level:North:East: South:West:

62957,56864,82245,60141,880

Miles

0 1 2 4

2007 Castle Rock FireBurned Area by Elevation

ELEVATION

Acres Burned

5859 - 6000

6000 - 7000

7000 - 8000

8000 – 9000

9000 - 9189

5859 – 6000:

6000 – 7000:

7000 – 8000:

8000 – 9000:

9000 – 9189:

1,012

53,110

108,431

48,545

521

Miles

0 1 2 4

Elevation (feet)

Low = 5859

High = 9189

2007 Castle Rock FireTopography

view looking north

2007 Runoff based increased Runoff Coefficients in the Streamflow Model after the 2007 Castle Rock Fire

2006 Runoff based increased Runoff Coefficients in the Streamflow Model after the 2007 Castle Rock Fire

Questions – Comments – CorrectionsThis presentation and Snowpack Needed for 2008 for Other Basins is available on

the Idaho Snow Survey Web Page at: http://www.id.nrcs.usda.gov/snow/

• Ron Abramovich, Water Supply Specialist

• USDA NRCS Snow Survey, Boise Idaho • Ron.Abramovich@id.usda.gov