Lower Colorado Water Supply Outlook, April 1, 2016

10% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 10% chance of being exceeded. Previously referred to as "Reasonable Maximum Forecast".

50% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 50% chance of being exceeded. Previously referred to as "Most Probable Forecast".

90% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 90% chance of being exceeded. Previously referred to as "Reasonable Minimum Forecast".

Acre-Foot (af): The volume equal to one acre covered one foot deep (43,560 cubic feet). See kaf below.

Average: The arithmetic mean. The sum of the values divided by the number of values. Values from 1981-2010 are used for this publication.

Categories: Much Above Average=Greater than 130%, Above Average=111-130%, Near Average=90-110%, Below Average=70-89%, Much Below Average=Less than 70%.

CBRFC: Colorado Basin River Forecast Center.

Forecast Period: The period from April 1 through July 31, unless otherwise noted.

kaf: Thousand Acre-Feet. See Acre-Foot above.

Inflow: The volume of water that flows into a reservoir or lake.

Median: The middle value of an ordered set of values. Half of the values are higher and half of the values are lower. When the set contains an even number of values the median is the average of the two middle numbers.

NOAA: National Oceanic and Atomospheric Administration.

NWS: National Weather Service.

Water supply forecasts take into consideration present hydrometeorological conditions and use average basin temperatures and precipitation for the forecast period. As the forecast season progresses, a greater portion of the future hydrologic and climatic uncertainty becomes known and monthly forecasts become more accurate. For more information on the tools we use, consult Water Supply Forecasting Tools.

Volume forecasts represent adjusted flows; that is, observed flows with upstream water use taken into account. Adjusted flows will closely approximate natural or unimpaired flows. However, not all upstream diversions or impoundments are measured or quantifiable. For specific adjustments used with each forecast point, consult the Guide to Water Supply Forecasting.

The Water Supply Outlook is issued monthly January through May by the Colorado Basin River Forecast Center. It represents a coordinated effort between the National Weather Service, Natural Resources Conservation Service, Bureau of Reclamation, U.S. Geological Survey and local water district managers.

Note: Data used in this report are provisional and are subject to revision.

For more information, or to be included on the mailing list, please contact:

Colorado Basin River Forecast Center
2242 W North Temple
Salt Lake City, UT 84116
(801) 524-5130
www.cbrfc.noaa.gov

	Forecast Period	90% Exceedance Volume	70% Exceedance Volume	50% Exceedance Volume	Percent Median	30% Exceedance Volume	10% Exceedance Volume
Salt
Roosevelt, Nr	January-May	197	200	205	66	210	230
	April-May	24	29	33	26	39	57
Tonto Ck
Roosevelt, Nr, Gun Ck, Abv	January-May	29	29	30	71	30	31
	April-May	1.1	1.5	2.1	36	2.6	3.3
Verde
Tangle Ck, Blo, Horseshoe Dam, Abv	January-May	94	95	97	62	101	105
	April-May	14.6	15.4	17	47	21	25

	Forecast Period	90% Exceedance Volume	70% Exceedance Volume	50% Exceedance Volume	Percent Median	30% Exceedance Volume	10% Exceedance Volume
Gila
Gila, Nr	January-May	50	50	51	91	52	55
	April-May	10.1	10.5	11	67	12.1	15.5
Virden, Nr, Blue Ck, Blo	January-May	62	62	62	82	63	67
	April-May	12.5	12.6	12.8	61	13.6	17.5
Solomon, Nr, Head Of Safford Vly	January-May	99	100	101	74	105	111
	April-May	21	22	23	59	27	33
San Carlos Res, Coolidge Dam, At	January-May	78	80	82	86	84	91
	April-May	3	4.7	7	38	8.8	15.5
San Francisco
Glenwood, Nr	January-May	21	21	21	100	22	23
	April-May	5.5	5.6	5.8	79	6.4	7.5
Clifton	January-May	39	40	40	66	41	47
	April-May	8.3	8.8	9.5	55	10.5	16

	Forecast Period	90% Exceedance Volume	70% Exceedance Volume	50% Exceedance Volume	Percent Median	30% Exceedance Volume	10% Exceedance Volume
Little Colorado
Lyman Lk, Abv, St. Johns, Nr	January-June	7.1	7.1	7.3	103	7.3	8.5
	April-June	0.77	0.85	1	29	1	2.2
Zuni
Black Rock Res, Abv	January-May	0.08	0.08	0.1	21	0.12	0.18
	April-May	0	0	0.02	20	0.04	0.1
Chevelon Ck
Winslow, Nr, Wildcat Cyn, Blo	January-May	13.6	13.7	14	101	14.1	15.6
	April-May	0	0.1	0.4	24	0.5	2

	EOM Contents	Percent EOM Average	Percent Usable Capacity	Last Year EOM	Last Year %Average	EOM Average	Usable Capacity
Salt
Roosevelt	863.1	84	52	799.8	78	1023.7	1653.0
Horse Mesa	225.9	96	92	225.4	96	235.3	245.1
Mormon Flat	54.7	101	95	55.4	102	54.4	57.9
Stewart Mountain	64.2	100	92	65.3	101	64.4	69.8
Horseshoe	49.2	75	45	70.5	108	65.4	109.2
Bartlett	73.7	53	41	119.1	86	138.0	178.2
untitled
TOTAL	1330.7	84	58	1335.5	84	1581.3	2313.2


Bill Williams
Alamo	50.2	34	5	67.4	46	146.8	1045.0
Agua Fria
Lake Pleasant	769.7	100	88	793.2	103	770.9	869.9
Gila
San Carlos	105.1	25	12	126.0	30	413.8	875.0
Colorado
Lake Powell	11019.0	65	45	10913.1	64	16941.7	24322.0
Lake Mead	10048.0	49	38	10419.0	51	20450.4	26120.0
untitled
TOTAL	21992.0	57	41	22318.6	58	38723.6	53231.9

Range		Round to
0-1.99		0.01
2.0-19.9		0.1
20-199		1.0
200-999		5.0
1000+		3 significant digits

Lower Colorado Water Supply Outlook, April 1, 2016

Lower Colorado Summary

Salt Basin Conditions

Gila Basin Conditions

Little Colorado Basin Conditions

Salt Specific Site Forecasts (kaf)

Gila Specific Site Forecasts (kaf)

Little Colorado Specific Site Forecasts (kaf)

Lower Colorado End of Month Reservoir Contents (kaf)

Precipitation Maps

Definitions

Additional Information