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Home My WebLink AboutWater Conditions in California - Report 4 May 1, 2017 i p z ods/ a �w O I a ll 0 a' 0 0 STATE OF CALIFORNIA Edmund G. Brown, Jr., Governor CALIFORNIA NATURAL RESOURCES AGENCY John Laird, Secretary for Natural Resources Department of Water Resources William A. Croyle Acting Director Cindy Messer Gary B. Bardini Taryn Ravazzini Katherine S. Kishaba Chief Deputy Director Deputy Director Deputy Director Deputy Director Mark E. Anderson Christy Jones Spencer Kenner Acting Deputy Director Acting Deputy Director Chief Counsel Division of Flood Management Eric Koch..................................................................................Chief, Division of Flood Management MauryRoos..............................................................................................................State Hydrologist Jon Ericson...........................................................................Chief, Hydrology and Flood Operations Sudhakar Talanki..........................................................................................Chief, Hydrology Branch Prepared by Frank Gehrke...........................................................................................Chief, Coop Snow Surveys Dave Rizzardo..................................................................................................Chief, Snow Surveys Sean DeGuzman.........................................................................................................Engineer, W.R. StephenNemeth.........................................................................................................Engineer, W.R. JohnKing.....................................................................................................................Engineer, W.R. AndrewReising...........................................................................................................Engineer, W.R. Matt Winston.............................................................................................Senior Meteorologist, W.R. COOPERATING AGENCIES Public Agencies State Water Project Contractors Buena Vista Water Storage District Municipalities East Bay Municipal Utility District City of Bakersfield Water Department Eldorado Irrigation District City of Los Angeles Department of Water and Power Friant Water Users Association City and County of San Francisco Hetch Hetchy Water and Power Kaweah Delta Water Conservation District State Agencies Kern Delta Water District University of California Kings River Conservation District Central Sierra Snow Laboratory Lower Tule River Irrigation District Scripps Institution of Oceanography Merced Irrigation District California Department of Forestry&Fire Protection Modesto Irrigation District California Department of Water Resources Nevada Irrigation District Public Utilities North Kern Water Storage District Pacific Gas and Electric Company Northern California Power Agency Southern California Edison Company Oakdale Irrigation District Federal Agencies Omochumne-Hartnell Water District U.S.Department of Agriculture Placer County Water Agency Forest Service(14 National Forests) Sacramento Municipal Utility District Natural Resource Conservation Service San Joaquin River Exchange Contractors Water Authority U.S.Department of Commerce South Feather Water and Power Agency National Weather Service South San Joaquin Irrigation District U.S.Department of Interior Tri-Dam Project Bureau of Reclamation Truckee River Basin Water Commission Geological Survey,Water Resources Tulare Lake Basin Water Storage District National Park Service(3 National Parks) Turlock Irrigation District U.S.Department of Army Yuba County Water Agency Corps of Engineers Private Organizations National Aeronautics and Space Administration J.G.Boswell Company Jet Propulsion Laboratory Kaweah and St.Johns River Association Other Cooperative Programs Kings River Water Association Nevada Cooperative Snow Surveys Tule River Association Oregon Cooperative Snow Surveys Summary of Water Conditions May 1, 2017 April was wet in the northern half of California but progressively drier in the south. The snowpack decreased at about the normal rate and remains at 180 percent of the May 1 average fairly close to the 2011 and 2006 amounts. Water year runoff in the Sacramento River region is forecast to exceed the 1983 record whereas the large San Joaquin region runoff is expected to be a bit less than in 1983. Overall, water year 1983 remains as California's wettest year. Forecasts of median April through July and water year runoff have been increased significantly from those made one month ago. A new record is likely for the Sacramento River system water year, but the April through July volumes are expected to be somewhat less than several previous high years. Snowpack water content is now about 180 percent of average for the date compared to 55 percent one year ago and about 15 percent less than the April 1 amount. Overall this year's May 1 pack is quite similar to snowpack water content in 2011 and 2006, and quite a bit less than 1983. Precipitation overall during April was above average, but dry in the south. The wettest regions were the Sacramento and North Lahontan; some southern stations reported little or no rain. Seasonal precipitation from October through April this year is about 170 percent of average compared to 110 percent last year at this time. Runoff so far this water year has been about 235 percent of average compared to 110 percent a year ago. Runoff in April was 200 percent of average. Estimated runoff of the eight major rivers of the Sacramento-San Joaquin River region was 6.94 million acre-feet in April. Reservoir storage is about 110 percent of average compared to 90 percent one year ago. Many large Sierra foothill reservoirs are being held down now in anticipation of large snowmelt runoff to come. SUMMARY OF WATER CONDITIONS _ IN PERCENT OF AVERAGE HYDROLOGIC REGION PRECIPITATION May 1 SNOW WATER May 1 RESERVOIR RUNOFF APR-JULY RUNOFF WATER YEAR OCTOBER 1 TO DATE CONTENT STORAGE OCTOBER 1 TO FORECAST RUNOFF DATE FORECAST NORTH COAST 160 160 115 200 155 180 SAN FRANCISCO BAY 175 100 215 CENTRAL COAST 155 --------� -- 100----- 250 - --- -- � SOUTH COAST_ 130 90 80 -- -- j j SACRAMENTO RIVER 190 170 110 240 200 225 SAN JOAQUIN RIVER 190 190 120 305 205 - 250 I i TULARE LAKE 175 200 100 265 205 225 NORTH LAHONTAN ^- ---- _. 210 _ 160---�- 140325^^- 325 --- 250 - 275 SOUTH LAHONTAN 140 205 85 110 205 170 COLORADO RIVER-DESERT 140 _ I STATEWIDE 170 180-- -- 110 ^^235_- -- - 200 230 DEPARTMENT OF WATER RESOURCES CALIFORNIA COOPERATIVE SNOW SURVEYS SEASONAL PRECIPITATION IN PERCENT OF AVERAGE TO DATE October 1 , 2016 through April 30, 2017 N NC aR. Statewide =170% NL 16 0 0X0 SR 10% -190 Y 0 J.- SF I.,," ptEl4, fN 175% 19�0% T Lf SL 175% cc 140% Hydrologic Regions 15506 NC - North Coast SF - San Francisco Bay CC - Central Coast Sc A V CR SC - South Coast fr 140% 30 SR - Sacramento River % SJ - San Joaquin TL - Tulare Lake NIL - North Lahontan SL - South Lahontan CR - Colorado River-Desert WATER YEAR IS OCTOBER 1 THROUGH SEPTEMBER 30 2 DEPARTMENT OF WATER RESOURCES CALIFORNIA COOPERATIVE SNOW SURVEYS FORECAST OF APRIL - JULY UNIMPAIRED SLT RUNOFF May 1, 2017' Legend SCOTT 16 100% Runoff forecast in percent of normal TRINITY 1530 UPPER SACRAMENTol 64% FEATHER 214% N YUBA 2130 TRUCKEE 276% 299% AMERICAN TAHOE 2260 CARSON 239% COSUMNEs 248 WALKER 229% MOKELUMNE 204 MONO* 192% STANISLAUs 2180 211% TUOLUMNE 201 OWENS MERCED 19 SAN JOAOU IN 19 KINGS M b KAWEAH 19 b TULE 23 o FERN /' FORECAST BY DEPARTMENT OF WATER AND POWER, CITY OF LOS ANGELES 3 MAY 1, 2017 FORECASTS APRIL-JULY UNIMPAIRED RUNOFF Unimpaired Runoff in 1,000 Acre-Feet (1) HYDROLOGIC REGION HISTORICAL FORECAST and Watershed 50 Yr Max Min of Apr-Jul Pck 80% Avg of Record Forecasts of Probability (2) Record (11) Avg Range(1) North Coast Trinity River at Lewiston Lake 639 1,593 80 980 153% 880 - 1,140 SACRAMENTO RIVER Upper Sacramento River Sacramento River at Delta above Shasta Lake 295 751 39 450 153% McCloud River above Shasta Lake 385 850 185 590 153% Pit River near Montgomery Creek+Squaw Creek 1,020 2,098 480 1,530 150% Total Inflow to Shasta Lake 1,756 3,525 711 2,880 164% 2,650 - 3,280 Sacramento River above Bend Bridge, near Red Bluff 2,421 5,117 943 4,030 166% 3,730 - 4,560 Feather River Feather River at Lake Almanor near Prattville (3) 333 675 120 720 216% North Fork at Pulga (3) 1,028 2,416 243 2,200 214% Middle Fork near Clio (4) 86 518 4 185 215% South Fork at Ponderosa Dam (3) 110 267 13 235 214% Feather River at Oroville 1,704 4,676 378 3,640 214% 3,370 - 4,050 Yuba River North Yuba below Goodyears Bar 279 647 51 590 211% Inflow to Jackson Mdws and Bowman Reservoirs (3) 112 236 25 240 214% South Yuba at Langs Crossing (3) 233 481 57 490 210% Yuba River near Smartsville plus Deer Creek 968 2,424 151 2,060 213% 1,920 - 2,210 American River North Fork at North Fork Dam (3) 262 716 43 590 225% Middle Fork near Auburn (3) 522 1,406 100 1,180 226% Silver Creek Below Camino Diversion Dam (3) 173 386 37 390 225% American River below Folsom Lake 1,199 3,074 185 2,710 226% 2,540 - 2,910 SAN JOAQUIN RIVER Cosumnes River at Michigan Bar 125 446 8 310 248% 275 - 360 Mokelumne River North Fork near West Point (5) 437 829 104 880 201% Total Inflow to Pardee Reservoir 457 1,076 75 930 204% 870 - 1,000 Stanislaus River Middle Fork below Beardsley Dam (3) 334 702 64 710 213% North Fork Inflow to McKays Point Dam (3) 224 503 34 490 219% Stanislaus River below Goodwin Reservoir(9) 682 1,710 116 1,490 218% 1,370 - 1,660 Tuolumne River Cherry Creek&Eleanor Creek near Hetch Hetchy 315 727 97 620 197% Tuolumme River near Hetch Hetchy 604 1,392 153 1,200 199% Tuolumne River below La Grange Reservoir(9) 1,193 2,682 301 2,400 201% 2,230 - 2,660 Merced River Merced River at Pohono Bridge 372 888 80 730 196% Merced River below Merced Falls(9) 623 1,587 104 1,240 199% 1,140 - 1,380 San Joaquin River San Joaquin River at Mammoth Pool (7) 1,026 2,279 235 2,010 196% Big Creek below Huntington Lake (8) 91 264 11 180 198% South Fork near Florence Lake (7) 201 511 58 390 194% San Joaquin River inflow to Millerton Lake 1,228 3,355 193 2,440 199% 2,250 - 2,710 TULARE LAKE Kings River North Fork Kings River near Cliff Camp (3) 239 565 50 460 192% Kings River below Pine Flat Reservoir 1,210 3,113 208 2,330 193% 2,180 - 2,530 Kaweah River below Terminus Reservoir 285 814 42 550 193% 500 - 620 Tule River below Lake Success 63 259 1 145 230% 130 175 Kern River Kern River near Kernville 384 1,203 83 910 237% Kern River inflow to Lake Isabella 458 1,657 57 1,110 242% 1,030 - 1,230 (1)See inside back cover for definition (5)36 year average based on years 1936-72 (2)All 50 year averages are based on years 1966-2015 (6)45 year average based on years 1936-81 unless otherwise noted (7)50 year average based on years 1953-2002 (3)5o year average based on years 1941-90 (8)50 year average based on years 1946-1995 (4)44 year average based on years 1936-79 4 MAY 1, 2017 FORECASTS WATER YEAR UNIMPAIRED RUNOFF Unimpaired Runoff in 1,000 Acre-Feet (1) HISTORICAL DISTRIBUTION FORECAST 50 Yr Max Min of Oct Water Pct 80% Avg of Record Thru Feb Mar Apr May Jun Jul Aug Sep Year of Probability (2) Record (11) Jan * * I * Forecasts Avg Range (1) 1348 2990 200 608 483 338 273 395 245 67 19 12 2,440 181% 2,335 - 2,605 860 1,965 165 1,183 2,353 557 3,002 5,150 1,484 5,831 10,796 2,479 2,948 2,713 1,251 1,257 840 490 293 248 235 10,275 176% 9,985 - 10,795 8,544 17,180 3,294 4,917 3,883 1,811 1,737 1,160 705 428 330 324 15,295 179% 14,900 - 15,965 780 1,269 366 2,417 4,400 666 219 637 24 291 562 32 4,407 9,492 994 2,756 2,920 1,216 1,513 1,220 660 247 143 115 10,790 245% 10,465 - 11,290 564 1,056 102 181 292 30 379 565 98 2,268 4,926 369 1,838 1,494 517 712 720 515 113 41 30 5,980 264% 5,815 - 6,175 616 1,234 66 1,070 2,575 144 318 705 59 2,626 6,382 349 2,384 1,950 694 894 940 695 181 45 27 7,810 297% 7,615 - 8,050 379 1,253 20 415 433 132 141 110 45 14 3 2 1,295 342% 1,255 - 1,350 626 1,009 197 748 1,848 129 424 408 176 223 340 284 83 14 8 1,960 262% 1,890 - 2,040 471 929 88 1,149 2,952 155 669 627 275 398 520 440 132 33 16 3,110 271% 2,980 - 3,295 461 1,147 123 770 1,661 258 1,909 4,631 383 1,048 829 400 526 750 760 364 78 25 4,780 250% 4,595 - 5,070 461 1,020 92 992 2,787 150 512 487 223 275 415 405 145 38 15 2,515 254% 2,405 - 2,670 1,337 2,954 308 112 298 14 248 653 71 1,793 4,642 327 700 530 355 516 725 790 409 128 42 4,195 234% 3,985 - 4,505 284 607 58 1,702 4,287 359 480 384 280 464 700 765 401 115 41 3,630 213% 3,470 - 3,850 451 1,402 89 158 163 101 134 180 170 66 17 6 995 221% 940 - 1,070 147 615 10 98 106 53 44 61 30 10 2 1 405 276% 385 - 440 558 1,577 163 728 2,318 130 184 228 180 279 340 305 186 70 38 1,810 249% 1,720 - 1,950 (9)Forecast point names based on USGS gage names.Stanislaus below Goodwin also known as inflow to New Melones,Tuolumne Riter below La Grange also known as inflow to Don Pedro,Merced River below Merced Falls also known as inflow to McClure. (10)Coordinated Forecast by National Weather Service Califomia-Nevada River Forecast Center and Department of Water Resources, State of California (11) For the tributaries,the period of record over which the minimum values are found does not include years after water year 2011. Unimpaired runoff in months prior to forecast date are based on measured flows 5 MAY 1, 2017 FORECASTS APRIL-JULY UNIMPAIRED RUNOFF Apr-Jul Unimpaired Runoff in 1,000 Acre-Feet(1) HYDROLOGIC REGION HISTORICAL FORECAST and Watershed 50 Yr Max Min Apr-Jul Pct Avg of of Forecasts of (2) Record Record Avg NORTH COAST Scott River Scott River nr Ft Jones(3) 173 398 22 279 161% Klamath River Total inflow to Upper Klamath Lake (4) 475 1,150 149 622 131% NORTH LAHONTAN Truckee River Lake Tahoe to Farad accretions 250 713 48 690 276% Lake Tahoe Rise(assuming gates closed,ft) 1.3 5.4 0.2 4.0 299% Carson River West Fork Carson River at Woodfords 52 135 10 120 231% East Fork Carson River near Gardnerville 182 407 43 440 242% Walker River West Walker River below Little Walker, near Coleville 153 330 35 310 203% East Walker River near Bridgeport 61 209 7 160 295% SOUTH LAHONTAN Owens River Total tributary flow to Owens River (5) 231 579 84 469 211% (1)See inside back cover for definition (2)All 50 year averages are based on years 1966-2015 unless otherwise noted (3)Forecast by National Weather Service California-Nevada River Forecast Center. 30 yr average(1981-2010) (4)Forecast by U.S.Natural Resources Conservation Service and National Weather Service California-Nevada River Forecast Center,April through September forecast, 30 year average based on years 1981-2010. (5)Forecast by Department of Water and Power,City of Los Angeles,average based on years 1965-2015 6 Snowpack Accumulation NORTH COAST REGION Water Content in % of April 1 Average SNOWPACK- f=irst of the month measurements made at 9 snow courses indicate an area wide 250 .................. .. ... - . .. ..... ................. snow water equivalent of less than 39.1 inch. 225 ......... . .. 200 .. ... This is 110 percent of the seasonal April 1 _ 175 average and 160 percent of the May 1 average. 150 ............................ Last year at this time the pack was holding less 125 .. ............... - than 15.1 inch of water. 100 - -... ... - 75 - ....... .,.. - 50 - 25 0 ...........- ..._._.. ..._... _ Jan 1 Feb 1 Mar 1 Apr 1 May 1 Precipitation October 1 to date in % of Average 200 175 - -- .... - - -- PRECIPITATION - Seasonal precipitation (October 150 ---------- j -- 1 through the end of last month) on this area was 125 --------- 160 percent of normal. Precipitation last month 100 ...:_. - -- - - was about 185 percent of the monthly average. 75 - . Seasonal precipitation at this time last year stood ...... at 120 percent of normal. 50 ...i.. - .. ... .. _ .. - 25 ... `` - Smith Klamath Trinity Eel Russian Reservoir Storage Contents of major reservoirs in % of capacity 100--------- -- --- --- --- ---- --- --- ------ ---- ---------------------- so ._.. --- ----- RESERVOIR STORAGE- First of the month sa storage in 6 reservoirs was 2.8 million acre-feet aD which is 115 percent of average. About 90 percent of available capacity was being used. 20 ...... __ Storage in these reservoirs at this time last year was 80 percent of average. D ......-.. /...._..... - Klamath Trinity Eel Russian WY2016 i=f1/;WY2017 --► 10 Yr avg Runoff October 1 to date in % of average 250 i- -------------------------- ----- --- --- --------------- ---------------------- 225 _---- -....... -- - --- ------------------------------------- 200 ! ......... --- --- -- ---- ----------- 175 — 150 -I -... ..-.. .._- - .- --- -----/ .. 125�- - - RUNOFF -Seasonal runoff of streams draining the ioD ; ...... -- area totaled 20.8 million acre-feet which is 200 7.50 5- percent of the average for this period. Last year, 25 runoff for the same period was 120 percent of o average. Klamath,Copco Trinity Eel Russian to Orleans 7 Snowpack Accumulation SACRAMENTO RIVER REGION Water Content in % of April 1 Average SNOWPACK- First of the month measurements made at 65 snow courses indicate an area wide 250 - --- - -- - - snow water equivalent of 40.9 inches. This is 120 225 ...: ...... .... ..- .. - - - - - -- - - - percent of the seasonal April 1 average and 170 200 ....... .... ........ . .... ------ 175 ----175 percent of the May 1 average. Last year at this 150 ............. - time the pack was holding 14.6 inches of water. 125..... _ .... ... ..... 100 :.... . ........ . -.. . -.. .., - .. 75 .............. 50 :...._ .,_..: ..... ...... ... .... ..... ....... 25 ... .. - 0 Jan i Feb i Mar 1 Apr 1 May 1 Precipitation October 1 to date in % of Average 250 225 PRECIPITATION - Seasonal precipitation (October 200f - / 1 through the end of last month) on this area was 175 - f �... 190 percent of normal. Precipitation East month 150 was about 220 percent of the monthly average. 125 _ .._-. /.... .... 100 ��` Seasonal precipitation at this time last year stood _!...... -- ---- 75 ... . ------ . ...... . ...... at 120 percent of normal. 20 /. - / ...... .. ...... Upper Feather Yuba American Mokelumne Sacramento Reservoir Storage RESERVOIR STORAGE- First of the month storage in 43 reservoirs was 14.1 Contents of rnajor reservoirs in % of capacity million acre-feet which is 110 percent of loo -------- _. _. / average. About 85 percent of available - / capacity was being used. Storage in so = - these reservoirs at this time last year was 105 percent of average. 60 -; -- 40 -r 24 / 0 [z/ -- /-- Z- f _ Sacra Feather Yuba American Stony Cache Pulah Mokelumne mento Runoff RUNOFF - Seasonal runoff of streams draining the area totaled 31.2 million October 1 to date in %of average acre-feet which is 240 percent of average for this a period. La t year, runoff for the same period was / 105 pert of average. e - - / - The Sacramento Region 40-30-30 Water °° _.:.... ._ .-..--.---- ---.-.---..�:. .-. .-. ....... ...� Supply Index is forecast to be 14.9 assuming 2° - - -. .: �-----------�--- median meteorological conditions for the remainder of the year. This classifies the year as .,wet" in the Sacramento Valley according to the State Wafter Resources Control Board. o t - Shasta Inflow Feather Yuba American Mokelumne 8 SAN JOAQUIN RIVER AND TULARE Snowpack Accumulation LAKE REGIONS Water Content in % of April 1 Average SNOWPACK First of the month measurements 250 225 made at 55 San Joaquin Region snow courses 200 indicate an area wide snow water equivalent of 175 . .... ........ 53.6 inches. This is 160 percent of the seasonal 150 - - - . (April 1) average and 190 percent of the May 1 125 - average. Last year at this time the pack was 100 holding less than 18.6 inch of water. At the same 75 - time 42 Tulare Lake Region snow courses 50 indicated abasin-wide snow water equivalent of 25 41.2 inches which is 155 percent of the average ofor April 1 and 200 percent of May 1. Last year at Jan 1 Feb 1 Mar 1 Apr 1 May t this time the basin was holding less than 11.4 Precipitation inch of water. October 1 to date in % of Average 250 - PRECIPITATION - Seasonal precipitation (October 225 - 1 through the end of last month) on the San zoo _ . Joaquin Region was 185 percent of normal. 175 7 % / / - / Precipitation last month was about 155 percent of jf the monthly average. Seasonal precipitation at 125 j / f /' / this time last year stood at 110 percent of normal. 100 j Seasonal precipitation on the Tulare Lake 75 so / . . Region was 175 percent of normal. Precipitation .. 25last month was about 110 percent of the monthly j - i... /... 1.,.. /.. . ... i- average. Seasonal precipitation at this time last Stanislaus Merced Kings Tule year stood at 110 percent of normal. Tuolumne San Joaquin Kaweah Kern Reservoir Storage RESERVOIR STORAGE- First of the month storage in 34 San Joaquin Region reservoirs Contents of major reservoirs in % of capacity was 9.1 million acre-feet which is 120 percent of 100 .... average. About 80 percent of available capacity was being used. Storage in these reservoirs at $a • • � ....... - - - — ---•:... .... Z_ - this time last year was 75 percent of average. First of the month storage in 6 Tulare Lake sa Region reservoirs was 1 million acre-feet which s g l i --` % ao �-... - ... ,... -. .... - ..;..... � 00 pert average a 50e in these percent 1 percent of av and about of ava 20 ....... .. this itime last year was 85 percent of average. at ... ° RUNOFF- Seasonal runoff of streams draining the Stanislaus Tuolummnen Merced San SanJaaquin Kings Kern ff San Joaquin Region totaled 10.7 million acre- WY2o16 :f Z!WY2017 . - 10 Yr Avg feet which is 305 percent of average for this October 1 to date in % of average period. Last year, runoff for the same period was g 105 percent of average. Seasonal runoff of -- -- --- - - -- -- ---- -- streams draining the Tulare Lake Basin totaled ° f 3.4 million acre-feet which is 265 percent of % f j 7 average for this period. Last year runoff for this f j j j same period was 75 percent of average. j The San Joaquin Region 60-20-20 Water r r ° Supply Index is forecast to be 6.2 assuming 75 / percent of median meteorological conditions. IL0 This classifies the year as "wet" in the San I `i 1 q 9 g as uin River Region according to the State Water 0 1.... /: 1:_ Resources Control Board. Tuolumne San Joaquin Kaweah Kern Stanislaus Merced Kings Tule 9 NORTH AND SOUTH LAHONTAN Snowpack Accumulation REGIONS Water Content in % of April 1 Average SNOWPACK First of the month measurements 250 .-. . ........... ......... ... . .- - - ................... made at 5 North Lahontan Region snow 225- ..... ...................... ............... 200- ,.. courses indicate an area wide snow water _ 175 - ..-__- . equivalent of 34.4 inches. This is 140 percent of 150 .... the seasonal (April 1) average and 160 percent of 125 .. - ................ the May 1 average. Last year at this time the 100 ..... ................ .. --- pack was holding less than 11 inch of water, At 75 : =: the same time 7 South Lahontan snow courses Sa . .... . ..... .. indicated a basin-wide snow water equivalent of 25 -. ..._. - 27.6 inches which is 180 percent of the seasonal o (April 1) average and 205 percent of the May 1 Jan 1 Feb 1 Mar 1 Apr 1 May 1 average. Last year at this time the basin was Precipitation holding 9 inches of water. October 1 to date in % of Average 250 ...........- .... ----- 225 ...225 -.- - - - -------- - -- - ------------------- ...... PRECIPITATION - Seasonal precipitation (October 200 - T... 1 .._. 1 through the end of last month) on the North 175 -- -- --. .. - - Lahontan Region was 210 percent of normal. 125 - ` / Precipitation last month was about 285 percent of the monthly average. Seasonal precipitation at ... this time last year stood at 120 percent of normal. 75 ........... 50 - --- Seasonal precipitation on the South Lahontan 25was 140 percent of normal. Precipitation last - , , .. D .=-- -!--- � � _ � � _ l-; month was 65 percent of the monthly average. Surprise Tahoe- Carson- Mono Death Val- Mojave Seasonal precipitation at this time last year stood Valley Truckee Walker Owens fey Desert at 85 percent of normal, Reservoir Storage Contents of major reservoirs in % of capacity 100 ............................ . ..................... RESERVOIR STORAGE- First of the month storage in 5 North Lahontan reservoirs was 803 thousand acre-feet which is 140 percent of - ...... ---------- average. About 75 percent of available capacity /- was being used. Storage in these reservoirs at 40 this time last year was 30 percent of average. 20 - / IWO -f- Lake Tahoe was 5 feet above its natural rim on May 1. First of the month storage in 8 South Lahontan reservoirs was 222 thousand acre-feet Truckee East Walker Mono Basin Owens Basin which is 85 percent of average and about 55 WY2016 CC f WY2017 . 10 Yr Average percent of available capacity. Storage in these reservoirs at this time last year was 90 percent of Runoff average. October 1 to date in % of average -. ---------------------- ------- - -------------------------------------------- - 30 1 f_ - - - RUNOFF- Seasonal runoff of streams draining the ---------- _.._ ...-. ' --_ ._.._._. . --- ------------- ----. -- North Lahontan Region totaled 1.3 million acre-feet which is 325 percent of average for this ---........ .......:::::: :::: : - --- ------ -�:-:::::- : l , ----------- period. Last year, runoff for the same period was -- % 110 percent of average. Seasonal runoff of the - :- Owens River in the South Lahontan totaled 82 ,�� --- --- thousand acre-feet which is 110 percent of i average for this period. Last year runoff for this I_. /- ./--- - -.4.— same period was 50 percent of average. Truckee-Tahoe Carson Walker Owens to Farad 10 Precipitation SAN FRANCISCO BAY AND CENTRAL COAST REGIONS October I to date in % of Average 250 - .... .. ... .......................... .. .... PRECIPITATION - Seasonal precipitation (October 225 - - ............. 1 through the end of last month) on the San 200 - - Francisco Bay Region was 175 percent of 175 normal. Precipitation last month was about 130 150 j, _ percent of the monthly average. Seasonal 125 7 precipitation at this time last year stood at 110 .... 100 ..... 75 / ... percent of normal. 50 .. . 25 %/ - j Seasonal precipitation on the Central Coast o - - -�f -� Region was 155 percent of normal. Precipitation San Francisco Paiaro Salinas Santa Maria- last month was about 80 percent of the monthly Bay Santa Ynez average. Seasonal precipitation at this time last Reservoir Storage year stood at 90 percent of normal. Contents of major reservoirs in % of capacity 100 - ................................ RESERVOIR STORAGE- First of the month as • .� storage in 17 San Francisco Bay Region ea 40 - ...... /. .✓................... reservoirs was 525 thousand acre-feet which is 100 percent of average. About 75 percent of available capacity was being used. Storage in 20 - -.- these reservoirs at this time last year was 95 1 z 0 percent of average. North Bay Southeast Peninsula Salinas Santa Ynez Bay First of the month storage in 6 Central Coast Region reservoirs was 686 thousand acre-feet �VVY2016 /:,/-"/WY2017 r 10 Yr Avg which is 100 percent of average and about 70 percent of available capacity. Storage in these reservoirs at this time last year was 30 percent of Runoff average. October 1 to date in % of average 0 o° .Wz� RUNOFF- Seasonal runoff of the Napa River in '-------------�..-.--------------�._...... . .. . . - the San Francisco Bay Region totaled 150 h° thousand acre-feet which is 215 percent of . / � ous average for this period. Last year, runoff for the same eriod was 75 percent of average. Seasonal runoff of streams draining the Central ° --- -- Coast Region totaled 767 thousand acre-feet Napa nr St. Fie- Arroyo Seca nr Nacimiento which is 250 percent of average for this period. lena Soledad Last year runoff for this same period was 45 percent of average. 11 SOUTH COAST AND COLORADO RIVER REGIONS PRECIPITATION - October through April (seasonal) precipitation on the South Coast Region was 130 percent of normal. April precipitation was 10 percent of the monthly average. Seasonal precipitation at this time last year was 55 percent of normal. Seasonal precipitation on the Colorado River-Desert Region was 140 percent of normal. Precipitation during April was 0 percent of average. Seasonal precipitation at this time last year stood at 75 percent of average. RESERVOIR STORAGE - May 1 storage in 29 major South Coast Region reservoirs was 1.4 million acre- feet or 90 percent of average. About 65 percent of available capacity was being used. Storage in these reservoirs at this time last year was 70 percent of average. RUNOFF - Seasonal runoff from selected South Coast Region streams totaled 118 thousand acre-feet which is 80 percent of average. Seasonal runoff from these streams last year was 20 percent of average. COLORADO RIVER The April July inflow to Lake Powell is forecast to be 8.8 million acre-feet, which is 123 percent of average. The May 1 snowpack in the Colorado River basin above Lake Powell was 110 percent of average, lowest in the Muddy/Fremont/Escalante at 30 percent and highest in the Upper Green at 165 percent. On May 1 combined storage in Lakes Powell, Mead, Mohave and Havasu was about 24.8 million acre-feet or about 65 percent of average. About 45 percent of available capacity was in use. Last year at this time, these reservoirs were storing 60 percent of average. 12 MAJOR WATER DISTRIBUTION PROJECTS RESERVOIR STORAGE (AVERAGES BASED ON 1951.2000 OR PERIOD RECORD) AVERAGE STORAGE AT END OF April RESERVOIR CAPACITY STORAGE 2016 2017 PERCENT PERCENT 1,000 AF 1,000 AF 1,000 AF 1,000 AF AVERAGE CAPACITY STATE WATER PROJECT Lake Oroville 3,538 2,857 3,400 2,622 92% 74% San Luis Reservoir (SWP) 1,062 937 556 1,032 110% 97% Lake Dei Valle 77 39 40 41 104% 53% Lake Silverwood 78 69 66 66 95% 84% Pyramid Lake 180 163 162 166 101% 92% Castaic Lake 325 288 178 301 104% 93% Perris Lake 131 105 47 58 55% 44% CENTRAL VALLEY PROJECT Trinity Lake 2,448 1,984 1,494 2,302 116% 94% Lake Shasta 4,552 3,872 4,233 4,263 110% 94% Whiskeytown Lake 241 233 237 232 100% 96% Folsom Lake 977 727 826 724 100% 74% New Melones Reservoir 2,400 1,483 622 2,002 135% 83% Millerton Lake 520 358 295 261 73% 50% San Luis Reservoir(CVP) 971 839 401 966 115% 100% COLORADO RIVER PROJECT Lake Mead 26,159 18,823 9,693 10,420 55% 40% Lake Powell 24,322 16,854 11,014 12,149 72% 50% Lake Mohave 1,810 1,670 1,746 1,684 101% 93% Lake Havasu 648 587 597 594 101% 92% EAST BAY MUNICIPAL UTILITY DISTRICT Pardee Res 204 184 180 200 109% 98% Camanche Reservoir 417 265 240 283 107% 68% East Bay (4 res.) 159 134 135 134 100% 84% CITY AND COUNTY OF SAN FRANCISCO Hetch-Hetchy Reservoir 360 189 281 283 149% 79% Cherry Lake 268 176 181 183 104% 68% Lake Eleanor 29 17 22 24 140% 84% South Bay/Peninsula (4 res.) 238 173 156 152 88% 64% CITY OF LOS ANGELES(D.W.P.) Lake Crowley 183 124 111 93 75% 50% Grant Lake 48 26 17 33 126% 70% Other Aqueduct Storage (6 res.) 95 75 66 61 81% 64% 13 TELEMETERED SNOW WATER EQUIVALENTS May 1,2017 (AVERAGES BASED ON PERIOD RECORD) INCHES OF WATER EQUIVALENT BASIN NAME APRIL 1 PERCENT 24 HRS 1 WEEK STATION NAME ELEV AVERAGE May 1 OF AVERAGE PREVIOUS PREVIOUS TRINITY RIVER Peterson Flat 7150' 29.2 49.2 168.4 50.1 52.3 Red Rock Mountain 6700' 39.6 70.3 177.5 71.8 76.2 Bonanza King 6450' 40.5 - - - - Shimmy Lake 6400' 40.3 - - - - Middle Boulder 3 6200' 28.3 - - - - Highland Lakes 6030' 29.9 --T - - 30.7 Scott Mountain 5900' 16.0 17.5 109.4 18.5 21.0 Mumbo Basin 5650' 22.4 27.1 121.1 28.2 31.6 Big Flat 5100' 15.8 18.8 119.2 19.7 22.3 Crowder Flat 5100' - 0.0 - 0.0 0.0 SACRAMENTO RIVER Cedar Pass 7100' 18.1 18.7 103.3 19.5 18.8 Blacks Mountain 7050' 12.7 10.9 86.0 11.8 13.7 Sand Flat 6750' 42.4 54.1 127.6 54.5 55.1 Medicine Lake 6700' 32.6 45.6 139.8 46.7 48.0 Adin Mountain 6200' 13.6 9.4 69.1 10.1 12.7 Snow Mountain 5950' 27.0 44.2 163.6 45.2 47.8 Slate Creek 5700' 29.0 34.2 117.9 36.7 41.5 Stouts Meadow 5400' 36.0 38.3 106.3 39.0 42.2 FEATHER RIVER Lower Lassen Peak 8250' --- - - - - Kettle Rock 7300' 25.5 43.9 172.2 44.6 46.1 Grizzly Ridge 6900' 29.7 39.6 133.3 40.1 41.6 Pilot Peak 6800' 52.6 68.8 130.8 70.2 73.2 Gold Lake 6750' 36.5 68.0 186.2 68.6 69.6 Humbug 6500' 28.0 - - - - Harkness Flat 6200' 28.5 22.9 80.4 24.1 27.3 Rattlesnake 6100' 14.0 19.6 139.7 20.9 25.7 Bucks Lake 5750' 44.7 52.1 116.5 52.7 54.5 Four Trees 5150' 20.0 - - - - EEL RIVER Hull Mountain 6461' - - - - - Noel Spring 5100' - 0.0 - 0.0 0.0 YUBA&AMERICAN RIVERS Schneiders 8750' 34.5 63.4 241.7 83.4 83.8 Lake Lois 8600' 39.5 - - - - Carson Pass 8353' - 56.4 - 57.9 60.2 Caples Lake 8000' 30.9 54.1 175.1 54.4 56.2 Alpha 7600' 35.9 50.2 139.7 51.0 53.5 Forni Ridge 7600' 37.0 60.8 164.2 62.8 66.0 Meadow Lake 7200' 55.5 - - - - Silver Lake 7100' 22.7 32.2 141.7 33.2 37.2 Central Sierra Snow Lab 6900' 33.6 62.7 186.6 63.7 67.5 Van Vleck 6700' 35.9 54.8 152.6 56.4 60.3 Huysink 6600' 42.6 49.4 116.1 49.9 51.5 Robinson Cow Camp 6480' - 63.4 - 64.5 65.8 Robbs Saddle 5900' 21 A 13.0 60.9 14.3 18.4 Greek Store 5600' 21.0 19.8 94.3 21.5 25.0 Blue Canyon 5280' 9.0 0.0 0.0 0.0 2.8 Robbs Powerhouse 5150' 5.2 0.0 0.0 0.0 0.0 MOKELUMNE&STANISLAUS RIVERS Deadman Creek 9250' 37.2 68.9 185.2 69.1 69.7 Highland Meadow 8700' 47.9 97.3 203.2 98.3 99.5 Gianelli Meadow 8400' 55.5 77.0 138.8 77.5 77.8 Lower Relief Valley 8100' 41.2 -- - -. - Blue Lakes 6000' 33.1 60.0 181.3 60.4 62.0 Stanislaus Meadow 7750' 47.5 79.2 166.7 80.6 83.6 Bloods Creek 7200' 35.5 38.2 107.5 39.2 41.8 Black Springs 6500' 32.0 31.3 97.9 32.6 34.4 TUOLUMNE&MERCED RIVERS Dane Meadows 9800' 27.7 48.0 173.3 49.0 52.2 Slide Canyon 9200' 41.1 90,6 220.4 91.0 91.9 Tuolumne Meadows 8600' 22.6 39.1 172.8 40.3 44.0 Horse Meadow 8400' 48.6 101.0 207.9 102.5 105.2 Ostrander Lake 8200' 34.8 - - - - Lake Tenaya 8150' 33.1 57.0 172.2 58.0 62.9 White Wolf 7900' - 46.3 - 47.7 50.9 Paradise Meadow 7650' 41.3 --- - - - Lower Kibble Ridge 6700' 27.4 13.2 48.1 14.3 18.1 14 SAN JOAQUIN RIVER Volcanic Knob 10050' 30.1 55.0 185.9 57.0 59.1 Kaiser Point 9200' 37.8 68.8 181.9 69.1 71.5 Green Mountain 7900' 30.8 47.4 153.9 48.8 55.6 Devil's Postpile 7569' - 19.5 - 20.3 22.5 Tamarack Summit 7550' 30.5 28.3 92.9 30.1 36.1 Chilkoot Meadow 7150' 38.0 39.6 104.2 40.8 43.3 Huntington Lake 7000' 20.1 14.0 69.9 15.4 19.9 Graveyard Meadow 6900' 18.8 - - - - Poison Ridge 6900' 28.9 11.5 39.9 13.7 20.0 KINGS RIVER Bishop Pass 11200' 34.0 31.3 92.1 32.5 36.4 Charlotte Lake 10400' 27.5 - - - - State Lakes 10300' 29.0 69.6 240.1 69.8 70.7 Mitchell Meadow 9900' 32.9 64.3 195.6 64.3 64.1 Upper Burnt Corral 9700' 34.6 63.2 182.6 64.0 66.7 West Woodchuck Meadow 9100' 32.8 60.2 1183.5 60.1 63.0 Big Meadows 7600' 25.9 17.8 68.6 19.0 24.5 KAWEAH&TULE RIVERS Quaking Aspen 7200' 21.0 4.6 21.7 5.9 12.2 Giant Forest 6650' 10.0 0.0 0.0 0.0 0.0 KERN RIVER Upper Tyndall Creek 11400' 27.7 - - - - Chagoopa Plateau 10300' 21.8 46.7 214.1 46.7 52.2 Pascoes 9150' 24.9 42.8 171.9 43.7 49.7 Wet Meadows 8950' 30.3 - - - - Tunnel Guard Station 8900' 15.6 1.0 6.5 2.0 10.4 Beach Meadows 7650' 11.0 0.0 0.0 0.0 0.5 SURPRISE VALLEY AREA Dismal Swamp 7050' 29.2 50.9 174.3 50.8 49.2 TRUCKEE RIVER Big Meadows 8700' 25.7 47.2 183.7 48.2 51.5 Independence Lake 8450' 41.4 86.8 209.6 86.4 86.2 Squaw Valley 8200' 46.5 77.6 166.9 78.8 81.3 Independence Camp 7000' 21.8 19.1 87.6 20.0 23.0 Independence Creek 6500' 12.7 4.3 33.9 5.3 9.5 Truckee 2 6400' 14.3 20.9 146.2 22.3 27.0 LAKE TAHOE BASIN Mount Rose Ski Area 8900' 38.5 - - - 93.7 Heavenly Valley 8800' 28.1 55.1 196.1 54.8 57.2 Hagans Meadow 8000' 16.5 28.1 170.3 28.9 33.0 Marlette Lake 8000' 21.1 43.6 206.6 45.4 48.2 Echo Peak 5 7800' 39.5 70.7 179.0 71.5 75.4 Rubicon Peak 2 7500' 29.1 56.0 192.4 56.0 57.9 Tahoe City Cross 6750' 16.0 6.6 41.2 7.9 12.3 Ward Creek 3 6750' 39.4 55.6 141.1 57.1 62.1 Fallen Leaf Lake 6250' 7.0 0.0 0.0 0.0 0.0 CARSON RIVER Ebbetts Pass 8700' 38.8 79.1 203.9 79.4 81.2 Horse Meadow 8557' - 46.2 - 46.3 46.3 Monitor Pass 8350' - 29.2 - 30.3 33.5 Burnside Lake 8129' - 27.9 - 29.6 43.0 Forestdale Creek 8017' - 46.6 - 45.8 49.1 Poison Flat 7900' 15.2 39.5 243.8 40.6 44.6 Spratt Creek 6150' 4.5 0.0 0.0 0.0 0.0 WALKER RIVER Leavitt Lake 9600' - 120.8 - 120.7 123.2 Summit Meadow 9313' - 54.4 - 54.3 56.6 Virginia Lakes 9300' 20.3 36.7 180.8 37.0 39.4 Lobdell Lake 9200' 17.3 34.0 196.5 34.9 38.6 Sonora Pass Bridge 8750' 26.0 53.4 205.4 52.8 55.0 Leavitt Meadows 7200' 8.0 0.0 0.0 0.0 6.7 OWENS RIVER/MONO LAKE Gem Pass 10750' 31.7 48.7 153.7 48.6 49.6 Sawmill 10200' 19.4 33.7 173.8 34.7 33.7 Cottonwood Lakes 10150' 11.6 - - - - Big Pine Creek 9800' 17.9 41.9 234.0 41.8 45.3 Rock Creek Lakes 9700' 14.0 - -- - - South Lake 9600' 16.0 30.7 192.0 31.4 34.7 Mammoth Pass 9300' 42.4 79.8 188.2 80.3 80.9 NORMAL SNOWPACK ACCUMULATION EXPRESSED AS A PERCENT OF APRIL 1 ST AVERAGE AREA JANUARY FEBRUARY MARCH APRIL MAY Central Valley North 45%, 70% 90% 100% 75% Central Valley South 45% 65% 85% 100% 80% North Coast 40% 60% 85% 100% 80% 15 May 1 Statewide Conditions 250... 235 200 - 1.$ 185 185 0 - ..... ... 170 17 150 150 135..._..._ 1.4 _. . 140 ..... ....... - - 1 -- 7 `/ 31530 ° 7,05 �.. 105 110 1� 115 111a 0 �1 100 95 5 j 75 70 70 65 5 60 6005 55 / / 50 - 50 / � __... / 4 5 ✓ 2 ✓ V / r / 2; / .... / - - 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 :: -- Snowpackz Precipitation Runoff Reservoir Storage SNOWLINES It is with deep regret I note the passing of Fred A Strauss. Fred joined the then Division of Public Works in the Snow Surveys program in 1947 under the leadership of Fred Paget. It was a time of rapid expansion of the snow surveys program with the addition of additional snow courses as well as snow survey cabins, stimulated by the flooding of portions of Sacramento in late 1950 and the anticipated building of new large reservoirs to provide flood protection for downstream communities. Following Fred Paget's untimely death while on a cabin stocking trip in 1950 Strauss took over the reins. He was not one to shy away from change and innovation, admittedly not all of which were successful. In the success column was the initiation of convening a meeting of agency participants in the cooperative program in 1954, which continues to this day with only one year exception. Fred even had has own Airborne Snow Observatory with photographs taken from light aircraft used to supplement the manual surveys. Fred initiated an attempt at using helicopters to conduct manual snow surveys for the April, 1952 cycle in the Kern drainage, though there was no loss of life, the result recounted by Murt Stewart in Pat Armstrong's book The Log of a Snow Survey is quite hair raising. Fred was an active member of the Western Snow Conference, an organization dedicated to the art and practice of snow surveys in the western states and continued his participation in this organization throughout his career. He resigned from his position with snow surveys in 1954, perhaps hoping in vain to escape the 21111 EI Farsantee award for the most egregious forecasting foopah. Fred was a bridge between the early pioneers of snow surveys and runoff forecasting and we current practitioners. He was always willing to discuss current and past events. His last attendance at a Western Snow Conference was in Seattle last year and fortunately his banquet presentation is at https://www.youtube.com/watch?v= xuXg5AdhgA On this months cover are pictured the pioneers of snow surveys, seated Dr. Church and left to right F. T. Mayo, W. W. McLaughlin, Gov. George Clyde, George Lewis, Prof. Boardman, N.S. Hall and Fred Strauss ®OSP 17 142417 SNOWPACK-Snow data is a major index of spring and summer runoff from Sierra Nevada watersheds. April 1 data historically reflects the magnitude of the snowpack at or near the maximum seasonal accumulation. Averages are based on April 1 data for the period 1966-2015 (50 years, except for data sites established after .1951). PRECIPITATION-Averages for stations are based on the source of the data and varies from a 30 year to a 50 year period. RUNOFF AND FORECASTS -Runoff data and runoff forecasts are shown as unimpaired values. Unimpaired runoff represents the natural water production of a river basin, unaltered by upstream diversions, storage, or by export or import of water to or from other watersheds. Forecast of runoff assumes median conditions subsequent to the date of forecast. Runoff probability ranges are statistically derived from historical data. The 80 percent probability range is comprised of the 90 percent exceedence level value and the 10 percent exceedence level value. This means that actual runoff should fall within the stated limits eight times out of ten. Runoff averages for most streams are based on the period 1961-2010. Reservoir storage averages are based on the period from 1961 (or beginning of operation) to 2010. For more details contact California Cooperative Snow Surveys, P.O. Box 219000, Sacramento, CA 95821-9000, (916) 574-2983 or daver@water.ca.gov. INDICES OF WATER AVAILABILITY The Sacramento River water year unimpaire-drunoffis the sum of: Sacramento River above Bend Bridge, Feather River Inflow to Lake Oroville, Yuba River near Smartvilie and American River Inflow to Folsom Lake. The Sacramento Valley Water Year Hydrologic Classification W-30-30 Index). The values 40-30-30 represent the percentage weight given to the three variables in the formula for the index. The first variable is the forecasted unimpaired runoff from April through July (40 percent). The second variable is the forecasted unimpaired runoff from October through March (30 Percent). The third variable is the previous year's index with a cap to account for required flood control releases during wet years. The basins used in this computation are those used in the Sacramento River water year unimpaired runoff. The San Joaquin Valley Water Year Hydrologic Classification (60-20-20 Index). In a similar manner the values 60-20-20 represents the percentage weights on April through July runoff, October through March runoff and previous year's Index. The San Joaquin River unimpaired runoff is the sum of: Stanislaus River Inflow to New Melones Lake, Tuolumne River Inflow to New Don Pedro Reservoir, Merced River Inflow to Lake McClure and San Joaquin River.inflow to Millerton Lake. Runoff of the ei ht major rivers of the Sacramento and San Joaquin Regions is the sum of the runoff in the eight major rivers used in the two above indices. State of California — The Natural Resources Agency AIL DEPARTMENT OF WATER RESOURCES FIRST CLASS U.S. POOSTSTAGE GE P.O. Box 942836 PAID Sacramento, CA 94236-0001 SACRAMENTO CA BUTTErOiIN'ry PERMIT NO 424 ADMtNlS �Tro� MAY 252017 0p'01VILLE,CALIFORNI/s BUTTE COUNTY CHAIRMAN-BD OF SUPERVISORS 25 COUNTY CENTER DR OROVILLE CA 95965-3316 77- Foirst Class 1 01 1 1 Bill 5�"L•ox ry �P. 'Foxe KA••. FSS e v cr A w � m s o F- T o9CIFOF►��A