Heron and Elephant Butte Lake Levels

Weather prediction for Saturday, September 29, 2007 at Elephant Butte, NM:
84/58 F high/low temp, 25% chance rain, winds S 8-12 mph becoming SSW 12-16 mph, gusts to 24 mph. 7:02 a.m. sunrise, 6:56 p.m. sunset, 8:46 p.m. moonrise, moon waning gibbous 88% full

Heron Lake, New Mexico

September 27, 2007, 11:00 AM
7,152.65' elev., 230,884 acre feet
down 0.01 (1/8 inch) and 44 a.f. in 24 hours
even in past 71 hours
down 5.5 inches and 1,984 a.f. in 9 days

September 18, 2007, 11:00 AM
7,153.11' elev., 232,868 acre feet
Up 0.02' (1/4 inch) and 87 a.f. in 24 hours
Down 0.37 (4.4 inches) and 1,609 a.f. in 71 hours
Down 1 foot and 6,500 a.f. from summer high point in August.


Willow Creek, 11:00 AM, August 17, 2007, 120 cfs (4-296 cfs in past 71 hours). The lake level is going down a few to several inches each weekend when the Middle Rio Grande Conservancy District takes some water, but yesterday's rains helped the lake recover slightly.

Heron Lake, NM (Rio Arriba County)
date . . . . level (ft.) . . . storage (acre feet)
12/31 . . . 7,144.85 . . . . 198,729
01/31 . . . 7,137.54 . . . . 171,252
02/28 . . . 7,135.48 . . . . 163,997
03/31 . . . 7,136.80 . . . . 168,721
04/30 . . . 7,140.60 . . . . 182,435
05/31 . . . 7,148.98 . . . . 215,390
06/30 . . . 7,153.96 . . . . 236,551
08/07 . . . 7,154.64 . . . . 239,554
08/07 . . . 7,154.10 . . . . 241,581 (12:00 noon)
08/11 . . . 7,154.11 . . . . 241,581 (12:00 noon)
08/17 . . . 7,154.10 . . . . 241,581 (11:00 AM)
08/31 . . . 7,154.41 . . . . 238,536 end of month
09/18 . . . 7,153.11 . . . . 232,868 11:00 AM
09/27 . . . 7,152.65 . . . . 230,884 11:00 AM

102,888 a.f. SJ-C water in, January through August, 2007.
-4,267 a.f. SJ-C water loss, April-August
-11,499 a.f. SJ-C water discharged, May-August

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Elephant Butte Lake, New Mexico
Thursday, Sept. 27, 11:00 AM
4,328.10 feet elev. above benchmark with 362,593 acre feet
down 0.10' (1.2 inches) and 1,274 acre feet in 24 hours
down 0.32' (3.8 inches) and 3,495 acre feet in 71 hours
San Marcial Floodway is flowing at 145 cubic feet per second (139-203 cfs)
Flow out the dam is 1,010 cfs (994 to 1030 cfs in past 71 hours)


Tuesday, Sept. 18, 2007, 09:00 AM
4,329.32 feet elev. above benchmark with 375,974 acre feet
down 0.16' (1.9 inches) and 1,776 acre feet in 24 hours
down 0.44' (5.3 inches) and 4,878 acre feet in 71 hours
down 10 inches and 9,100 a.f. in 1 week.

San Marcial Floodway flows have been modest.

Flow out the dam at was 1,070 c.f.s. (1,040 to 1,080 cfs in past 71 hours).

Comparison to operations plan projections:
Ops plan projected lake level for the end of Sept. 18 was 4,327.29' elev., 353,784 a.f.
Ops plan had projected outflow of about 1,300 cfs from August 26 to Oct. 13.
The lake is 23 inches higher and has about 20,000 more a.f. of water than projected.
Although less water is flowing into the lake than projected, less is flowing out at the dam as well.

Elephant Butte Lake, 2007 elevation (feet) and acre feet of water:
1/01 . . . 4,340.82 . . . . 515,3500
1/31 . . . 4,344.02 . . . . 558,4400
2/28 . . . 4,346.88 . . . . 598,4600
3/11 . . . 4,347.72 . . . . 610,490 annual high point
3/19 . . . 4,347.48 . . . . 607,040
3/31 . . . 4,347.62 . . . . 609,050
4/30 . . . 4,343.82 . . . . 555,9700
5/05 . . . 4,342.26 . . . . 548,050 intermediate low point
5/31 . . . 4,347.08 . . . . 601,320
6/05 . . . 4,347.58 . . . . 608,480 crest of spring runoff
6/30 . . . 4,344.96 . . . . 571,440
7/25 . . . 4,337.90 . . . . 477,610
8/07 . . . 4,335.16 . . . . 443,660
8/17 . . . 4,333.72 . . . . 426,384
9/11 . . . 4,330.14 . . . . 385,080
9/18 . . . 4,329.32 . . . . 375,974
9/27 . . . 4,328.10 . . . . 362,593 (19.62' loss from maximum)


Operations Plan Predictions
08/16 . . . 4,332.39 . . . . 410,790
08/31 . . . 4,328.76 . . . . 369,750
09/18 . . . 4,327.29 . . . . 353,784 (actual on 9/27 is 4,328.10, 362,593)
09/30 . . . 4,325.16 . . . . 331,320
10/13 . . . 4,323.04 . . . . 309,654 (proj. max. loss of 10.68 from today)
10/27 . . . 4,324.20 . . . . 321,451

Maximum projected loss still leaves the lake 27' higher than the lowest level during the 2005 drought.

Projected outflow is 1,280 c.f.s. though to Oct. 12. Actual outflow on Sept. 27 was 1,010 cfs.

Reality check: The Butte probably won’t go below around 4,325.5 ft. elev. and 337,500 a.f.

During October, keelboats may be unable to use the Rock Canyon boat ramp unless heavy ramp clearing is done by the state park folks. (Some was done in mid-September.) However, the Dam Site ramp may be usable (although it no longer has a mast-raising pole).