nSan Juan Water Supply Outlook, June 1, 2017

San Juan Water Supply Outlook, June 1, 2017

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by Greg Smith
NOAA, National Weather Service
Colorado Basin River Forecast Center
Salt Lake City, Utah
www.cbrfc.noaa.gov

Contents

San Juan Summary






*Median of forecasts within each basin.


San Juan Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.


San Juan Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
San Juan
Pagosa Springs April-July215 220 225 105 230 240
June-July71 74 78 81 84 92
Carracas, Nr April-July380 385 390 103 395 405
June-July116 120 125 79 132 140
Navajo Res, Archuleta, Nr April-July685 700 710 97 735 760
June-July186 200 210 72 235 260
Farmington April-July1010 1030 1040 95 1080 1110
June-July330 345 355 76 395 425
Bluff, Nr April-July1040 1050 1070 97 1110 1150
June-July315 330 345 77 390 425
Rio Blanco
Pagosa Springs, Nr, Blanco Dam, Blo April-July52 54 56 104 58 61
June-July14 16 17.5 76 20 23
Navajo
Chromo, Nr, Oso Div Dam, Blo April-July63 67 69 106 73 76
June-July19 23 25 83 29 32
Piedra
Arboles, Nr April-July196 200 205 98 210 215
June-July55 59 63 85 69 74
Los Pinos
Vallecito Res, Bayfield, Nr April-July195 200 205 106 215 225
June-July83 88 93 94 101 113
Animas
Durango April-July370 380 385 93 400 425
June-July172 180 187 85 200 225
Florida
Lemon Res, Durango, Nr April-July46 49 51 93 53 59
June-July19 22 24 89 26 32
La Plata
Hesperus April-July25 27 28 122 30 31
June-July9 11 12 141 14 15
Mancos
Mancos, Nr April-July35 36 38 123 39 41
June-July11 12 14 135 15 17

Differences between the full period forecasts and the residual forecasts may not exactly equal the actual observed volumes due to rounding conventions (see Definitions section).

San Juan End of Month Reservoir Contents (kaf)

EOM
Contents		Percent
EOM
Average		Percent
Usable
Capacity		Last Year
EOM		Last Year
%Average		EOM
Average		Usable
Capacity
untitled Los Pinos
Vallecito Res, Bayfield, Nr 109.1 109 87 120.6 120 100.5 125.4
untitled San Juan
Navajo Res, Archuleta, Nr 1536.0 107 91 1549.4 108 1429.7 1696.0
untitled Florida
Lemon Res, Durango, Nr 36.0 112 90 35.0 109 32.1 39.8
untitled
TOTAL 1681.1 108 90 1705.0 109 1562.3 1861.2

Precipitation Maps




Definitions

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.

Rounding Conventions:
RangeRound to
0-1.990.01
2.0-19.90.1
20-1991.0
200-9995.0
1000+3 significant digits


Streamflow: The volume of water that flows past a specific stream site.

Water Year: The 12-month period, October 1 through September 30. The water year is designated by the calendar year in which it ends. Thus, the year ending September 30, 2008, is called the "2008 water year."


Additional Information

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


Hydrologist: Greg Smith