(a) The principal feature of this part is to obtain a reasonable level of efficiency in supplying water to the headgate by the District. The efficiency targets established by this part are the cornerstone of the enforcement and the incentive provisions and when implemented will aid other competing uses.

(b) The efficiency is readily calculable at the year's end, readily applicable to water appropriate to that year, able to be compared to other irrigation systems even though there may be many dissimilarities, appropriate for long term averaging, adjustable to any headgate delivery level including droughts or allocations, automatically adjusts to changes during the year and accurately accounts for misappropriated water. Efficiency also can be achieved through any number of measures from operations to changes in the facilities and can be measured as an end product without regard to the approach. Thus it is flexible enough to allow local decision making and yet is fact based to minimize disputes.

(c) Assuming the headgate deliveries are valid and enforceable, conveyance efficiency is the only remaining variable in determining the quantity of water needed to be supplied to the District. Conveyance efficiency is a measure of how much water is released into the irrigation system relative to actual headgate deliveries. Differences in efficiency, therefore, are directly convertible to acre-feet. The differences in efficiency, expressed as a quantity in acre-feet, may be added to or subtracted from the actual Lahontan Reservoir storage level before it is compared to the monthly storage objective. Thus, the diversions from the Truckee River, operation of other facilities (e.g., Stampede Reservoir) and decisions related to Lahontan Reservoir are made after the efficiency storage adjustments have been made. Operating decisions are made as if the adjusted storage reflected actual conditions.

(1) Efficiency incentive credits. In any year that the District's actual efficiency exceeds the target efficiency for the actual headgate delivery, two-thirds of the resultant savings, in water, will be credited to the District as storage in Lahontan. This storage amount will remain in Lahontan Reservoir as water available to the District to use at its discretion consistent with Nevada and Federal law. Such uses may include wetlands (directly or incidentally), power production, recreation, a hedge against future shortages or whatever else the District determines. The storage is credited at the end of the irrigation season from which it was earned. This storage “floats” on top of the reservoir so that if it is unused it will be spilled first if the reservoir spills. The District may use all capacity of Lahontan Reservoir not needed for project purposes to store credits.

(2) Efficiency disincentive debits. In any year that the District's actual efficiency falls short of the target appropriate to the actual headgate deliveries, then the resultant excess water that was used is considered borrowed from the future. Thus it becomes a storage debit adjustment to the actual Lahontan Reservoir storage level for determining all operational decisions. The debit may accumulate but may not exceed a maximum as defined in §418.13(b). The debit must be offset by an existing incentive credit or, if none is available, by a subsequent incentive at a full credit (not a 2⁄3 credit), or finally by a restriction of actual headgate deliveries by the District. This would only be done prospectively (a subsequent year) so the District and the water users can prepare accordingly. Since the debit does not immediately affect other competing uses or the District (except in a real drought), it allows for future planning and averaging over time.

(3) Efficiency targets. To determine the efficiency target, the system delivery losses were divided into categories such as seepage, evaporation and operational losses. The “reasonable” level of savings for each category was then determined by starting with current operating experience and applying the added knowledge from several measures. Means of achieving the efficiency targets, including the specific conservation measures and amounts, are identified in the table Possible Water Conservation Measures for the Newlands Project. Applicable target efficiencies will be determined each year as described in §418.13 (a)(4).

(4) Available conservation measures. The water conservation measures referred to in paragraph (c)(3) of this section and others currently available to the District are listed in the following table. The table has been revised based upon the Bureau of Reclamation's Final Report to Congress of the Newlands Project Efficiency Study, 1994.

(5) The measures in paragraph (c)(4) of this section are discretionary choices for the District. The range of measures available to the District provides a level of assurance that the target efficiency is reasonably achievable. The resultant efficiency targets were also compared to the range of efficiencies actually experienced by other irrigation systems that were considered comparable in order to provide a further check on “reasonable.” Most of the delivery losses are relatively constant regardless of the amount of deliveries. The efficiency will necessarily vary with the amount of headgate deliveries.

(6) The target efficiency for any annual valid headgate delivery can be derived from the table in Appendix A to this part.