Page 66 - Yucaipa Valley Water District

Director Memorandum No. 18-022 Page 20 of 22

( + )
Party Gap ($) = 1959−63 5 ∗
2
where,

( 1959−63 + 5 ) < 0, else Party Gap ($) = $0
2

Gap 1959-63 (acre-feet) = GWSY1959-63 + SW1959-63 - Demand Previous Year

Gap Last 5 Years (acre-feet) = GWSYLast 5 Years + SWLast 5 Years - Demand Previous Year + Net
New Recycled Previous Year
where,

GWSY1959-63 = local groundwater supplies available to a Party as a portion of their
base period safe yield.

The base period safe yield for the SBBA has been proportioned amongst the Parties
as described below:

where,

GWSY1959-63 = Safe Yield1959-63 – SW1959-63

SW1959-63 = average surface water usage by a party from 1953-1963

Demand Previous Year = total water demand calculated for the Party for the previous year
using published data, as approved by the Council.

GWSYLast 5 Years = local groundwater supplies available to a Party as a portion of their
current Safe Yield.

The safe yield of the last 5 years for the SBBA will be proportioned amongst the
Parties as described below.

where,

GWSYLast 5 Years = Safe YieldLast 5 Years – SWLast 5 Years

SWLast 5 Years = average surface water usage by a party within the last 5 years.

Net New Recycled Previous Year = The amount of recycled water from the previous year
minus Recycled 1959-63

where,

Recycled1959-63 is the amount of recycled water used in the base period

Sustainability ($) = Water Use x (Total Equitable Water Cost – Total Gap ($))

where,

Water Use (%) = Party Water Use (acre-feet)
Total Water Use (acre-feet)

Yucaipa Valley Water District - February 6, 2018 - Page 66 of 175