Monday, September 18, 2006

Weekend miscellany and lake conditions

With Tadpole's Friday night of architecture and a sleepover, a cat who wouldn't do well to have his medicine interrupted, and a need to accomplish boat projects at both the northern and southern lakes, many miles wound up being driven this weekend.

On Friday, we went south with a motor, boat compass, and assorted bits of gear; boat work got done but no sailing because of gusty winds.

Saturday we went north to Heron Lake, hauling the MacGregor out on the Etchells trailer so we could suspend the centerboard and replace the broken uphaul line on the centerboard. After finishing the repair, I snuck in a bit of sailing.

Sunday we went south to the Butte and did projects on Black Magic; this time we also got in a good sail. Winds were initially light and switchy, but we took off and had our patience rewarded as the best winds of the day filled in. We did several spinnaker jibes on our way north from the dam cove and sailed around the end of Horse Island to the bay between Marina del Sur and Rattlesnake Island before returning around sunset.

Elephant Butte Lakes continues to defy statistics and expectations by rising. The Butte now has 349,883 acre feet and is at 4,326.92 feet above benchmark elevation. It is up 1/4 inch and 213 acre feet in 24 hours and 1.2 inches and 1,062 a.f. in 72 hours. Only 18 c.f.s. is oozing out of the dam vs. 180 cubic feet per second coming into the lake via the San Marcial Floodway (492 c.f.s. maximum inflow in the past 72 hours.)

Cochiti Lake has 48,992 a.f., down 153 a.f. in 72 hours with an outflow of 503 cubic feet per second.

Heron Lake is at elevation 7.144.10 feet with 195,793 acre feet. Heron is up 1/2 inch and 157 acre feet in 24 hours; up about 3 inches and 1,000 a.f. in 72 hours. Willow Creek is flowing at 104 c.f.s. (96 c.f.s. minimum, 481 c.f.s. maximum in 72 hours).

For the month of August, Heron received 1,274 a.f. of Rio Grande water and 4,858 a.f. on San Juan-Chama water. 2,024 a.f. of Rio Grande water went out, along with 3,026 a.f. of San Juan-Chama water. 0 loss of San Juan-Chama water was recorded. At the end of August, Heron Lake had -243 a.f. of Rio Grande water and 193,625 a.f. of SJC water, 193,382 net a.f. at elevation 7,143.48. For the season to date, the lake has received 60,312 a.f. of SJC water, lost 5,560 a.f. of SJC water (net 49,752 a.f. compared to the nominal 96,200 a.f. for a "normal" year), and discharged 6,773 a.f. to the SJC water contractors.

Depending upon the spring runoff, the cove will dry out and leave the marina in the mud sometime in mid- to late February and the cove floor will wind up about six feet above the lake surface at the low point around early April.

About 24,000 a.f. (about 1/4 of the normal "full yield" of 2007 runoff will be needed for water to begin to reach the level of the cove floor. With normal runoff, this level might be achieved sometime around May 10--15.

About 36,000 a.f. (3/8 of normal yield) would allow the shallow draft portions of the marina to float in a few feet of water and allow pontoon boats and retractable centerboard boats to use parts of the marina. With normal runoff, this level might be achieved sometime around May 20--25.

About 48,000 a.f. (1/2 of full normal yield) would bring the marina cove to a depth of around six feet and allow most boats to use the marina and boat ramp. If 2007 is a "normal" year, this point might be reached somewhere close to Memorial Day. A good runoff year would allow the marina to be fully open and all ramps usable by Memorial Day weekend. A worse-than-average runoff might delay marina opening or require that part of the marina, if possible, be moved to deep water.


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