2007 Water Supply Summary Idaho Department of Water Resources

Atmospheric Sources and Sinks Streamflow River Basin Review: –Salmon –Big Wood –Snake –Boise –Bear and other Basins County Drought Declarations

UNIQUE APSECTS OF 2007 Below average snowpack followed by melting and runoff a month earlier than normal. Irrigation demand about the same as 2006 with similar above average temperatures in July and August, and below normal summer precipitation.

Precipitation was 66% of average in 2007

2007 Streamflow

2007 April-July Runoff Snake R. nr Heise* 1923 kaf 58 % of avg 6 th / 97 years Big Wood at Hailey % 12 / 92 Boise R. nr Boise* % 11 / 112 Payette at HSB* % 13 / 88 Weiser nr Weiser % 5 / 65 Snake at Weiser % 10 / 97 Salmon at Whitebird % 16 / 95 St. Joe at Calder % 19 / 88 Bear at Stewart Dam % 9 / 47 * Unregulated or natural flow

2006 April-July Runoff Snake R. nr Heise* 3621 kaf 109 % of avg 61 st / 96 years Big Wood at Hailey % 85 / 91 Boise R. nr Boise* % 96 / 111 Payette at HSB* % 74 / 87 Weiser nr Weiser % 62 / 64 Snake at Weiser % 78 / 96 Salmon at Whitebird % 58 / 94 St. Joe at Calder % 45 / 88 Bear at Stewart Dam % 11 / 46 * Unregulated or natural flow

Salmon

2007 APR-SEP VOLUME 4058 KAF 63 % OF AVERAGE

Big Wood

Upper Snake 2007 APR-SEP NATURAL FLOW SNAKE R NR HEISE 2371 KAF 57% AVG

Boise

Bear and Other River Basins

2007 County Drought Declarations

Precipitation at Winchester, Idaho

Summary Snow fall and runoff were below average in Record high summer temperatures and below average precipitation led to increase demands from irrigation storage A “normal” winter is needed to replenish reservoir storage to obtain sustainable water supplies for 2008