The El Dorado Irrigation District has 17,000 acre-feet of uncommitted water supplies classified as “firm yield,” the Board of Directors learned Monday.
The difference between water rights and firm yield is illustrated by Sly Park’s Jenkinson Lake, which holds 41,000 acre-feet of water and the district has rights to 32,000 of those acre-feet. But the firm yield is 20,920 acre-feet because the firm yield is based on a two-year supply, EID General Counsel Tom Cumpston explained in response to a query from the board.
The report, presented by Director of Engineering Brian Mueller, shows that 17,000 acre-foot surplus is enough to supply 28,000 homes (based on a district-wide average of 0.6 acre-foot per year per equivalent dwelling unit). That figure is based upon average water consumption of 0.77 acre-foot annually per equivalent dwelling unit in El Dorado Hills and 0.54 acre per EDU in the rest of the district.
“I think this really paints a picture that we do have an adequate supply of water,” said General Manager Jim Abercrombie.
The total firm yield is 63,500 acre-feet and the total potential demand is 46,500 acre-feet, leaving a firm yield balance of 17,000 acre-feet.
“These are firm yield supplies. We build dry year supplies into this report,” Cumpston said.
The potential demand includes 8,602 acre-feet in El Dorado Hills for existing homes and businesses and 430 acre-feet of meters bought and installed but not activated, plus 2,522 acre-feet of “other system demands.” Total potential demand in El Dorado Hills is 11,554.
In the rest of the district — from Cameron Park to Pollock Pines — the active demand is 28,090 acre-feet, the latent demand is 140 acre-feet and other system demands are 6,725 acre-feet for a total potential demand of 34,955 acre-feet.
These two systems — one pumping out of Folsom Lake and the other getting water from Sly Park and Project 184’s El Dorado Canal — total 46,509 acre-feet of potential demand but generate 63,500 acre-feet of firm yield.
El Dorado Hills has 29,110 acre-feet of water rights in Folsom Lake but the new El Dorado Hills Water Treatment Plant can only handle 15,163 acre-feet of water. That 29,000 acre-feet includes 17,000 acre-feet of newly acquired water rights for which the district is trying to get a delivery contract from the U.S. Bureau of Reclamation.
Not included in the firm yield is an additional grant of 15,000 acre-feet by an act of Congress and named after the representative who obtained it, former Rep. Vic Fazio.
“EID would also be the primary beneficiary of water rights filings submitted by El Dorado Water and Power Authority and currently pending before the State Water Resources Control Board for up to 40,000 acre-feet annually of water rights for long-term county needs, also to be stored in SMUD’s Upper American River Project reservoirs,” Cumpston told the Mountain Democrat later.
EID General Manager Jim Abercrombie added that the El Dorado County Water Agency is getting a drought supply reservation from the Sacramento Municipal Utility District’s Upper American River Project. That has been pegged at 15,000 acre-feet.
An additional factor affecting water availability in El Dorado Hills is the use of recycled water from the wastewater treatment plant delivered to houses in Serrano, including the golf course, for landscape watering. Parker Development representative Kirk Bone said the potable water consumption for such “dual-plumbed” houses is 0.4 acre-foot annually compared to the 0.77 average without recycled water.
Abercrombie agreed that number was accurate for dual-plumbed houses.
Bone also noted that the proposed Marble Valley and Lime Rock projects would use recycled water.