YEAR | APR | MAY | JUN | JUL | AUG | SEP | OCT2 | SEASON TOTAL |
1972 | 2.03 | 5.18 | 7.47 | 9.20 | 8.03 | 4.43 | 2.00 | 38.34 |
1973 | 2.28 | 5.40 | 9.22 | 11.48 | 9.80 | 4.60 | 2.00 | 44.78 |
1974 | 1.74 | 4.57 | 8.69 | 9.21 | 8.95 | 5.21 | 2.00 | 40.37 |
1975 | 1.72 | 5.26 | 8.33 | 10.49 | 8.88 | 4.66 | 2.00 | 41.34 |
1976 | 1.84 | 2.82 | 7.86 | 10.04 | 6.71 | 4.84 | 2.00 | 36.11 |
1977 | 1.69 | 4.49 | 6.67 | 8.32 | 5.43 | 4.32 | 2.00 | 32.92 |
1978 | 1.92 | 5.18 | 8.07 | 10.20 | 8.25 | 4.63 | 2.00 | 40.25 |
1979 | 2.10 | 3.78 | 8.11 | 9.45 | 8.31 | 3.28 | 2.00 | 37.03 |
1980 | 1.66 | 4.52 | 6.25 | 9.72 | 7.06 | 3.61 | 2.00 | 34.82 |
1981 | 1.61 | 4.26 | 6.19 | 8.53 | 7.63 | 3.76 | 2.00 | 33.98 |
1982 | 1.61 | 4.60 | 7.18 | 8.06 | 6.74 | 3.22 | 2.00 | 33.41 |
1983 | 1.44 | 5.20 | 6.66 | 7.18 | 6.53 | 3.89 | 2.00 | 32.90 |
1984 | 1.47 | 3.92 | 6.42 | 9.86 | 7.89 | 3.26 | 2.00 | 34.82 |
1985 | 1.72 | 5.18 | 8.34 | 10.71 | 7.93 | 3.13 | 2.00 | 39.01 |
1986 | 1.74 | 4.65 | 7.69 | 8.56 | 7.97 | 4.08 | 2.00 | 36.69 |
1987 | 1.88 | 4.75 | 7.30 | 8.28 | 8.09 | 4.46 | 2.00 | 36.76 |
1988 | 1.56 | 4.22 | 6.38 | 10.06 | 7.57 | 4.16 | 2.00 | 35.95 |
1989 | 1.79 | 4.47 | 7.65 | 9.40 | 7.13 | 4.43 | 2.00 | 36.87 |
1990 | 1.78 | 3.91 | 6.69 | 9.39 | 6.83 | 4.55 | 2.00 | 35.15 |
1991 | 1.87 | 4.21 | 6.41 | 10.00 | 7.42 | 4.48 | 2.00 | 36.39 |
1992 | 2.08 | 6.34 | 8.58 | 8.75 | 7.65 | 4.22 | 2.00 | 39.62 |
1993 | 1.10 | 4.75 | 6.36 | 7.46 | 7.20 | 3.90 | 2.00 | 32.77 |
1994 | 1.69 | 4.74 | 8.23 | 12.41 | 8.53 | 4.67 | 2.00 | 42.27 |
1995 | 1.47 | 5.28 | 7.90 | 10.52 | 7.90 | 4.66 | 2.00 | 39.73 |
1996 | 1.53 | 4.34 | 8.54 | 11.02 | 9.58 | 4.65 | 2.00 | 41.66 |
1997 | 1.14 | 4.27 | 7.22 | 9.16 | 7.30 | 3.48 | 2.00 | 34.57 |
1998 | 1.49 | 3.66 | 7.81 | 9.52 | 8.29 | 4.75 | 2.00 | 37.52 |
1999 | 1.60 | 4.57 | 8.03 | 9.31 | 7.26 | 4.00 | 2.00 | 36.77 |
2000 | 1.65 | 4.38 | 8.02 | 9.85 | 8.56 | 3.66 | 2.00 | 38.12 |
2001 | 1.39 | 4.98 | 7.06 | 10.23 | 7.65 | 4.35 | 2.00 | 37.66 |
2002 | 1.49 | 4.12 | 7.69 | 9.83 | 7.82 | 3.81 | 2.00 | 36.76 |
MO. AVG. SINCE 1972 | 1.68 | 4.58 | 7.52 | 9.55 | 7.77 | 4.17 | 2.00 | 37.27 ac-in |
1. | Data have already been adjusted using pan evaporation & KC value to approximate orchard tree water use. |
2. | The October value of 2 acre-inches was estimated based on miscellaneous October measurements provided by the WSU Tree Fruit Research Center, and conversations with Tim Smith, WSU Cooperative Extension. April through September values are based on data collected by T. Smith. |
* | Note: Actual irrigation rates must be 10 to 40% higher than tree use, depending on irrigation efficiency |
(This table is from the watershed plan, based on the State of Washington Irrigation Guide and supplemented by Washington State Tree Fruit Research data collected in Wenatchee WA.)
Table 4-15. Average monthly tree and pasture/turf irrigation water use (ac-in) estimates.
Description of6 Value | Apr | May | Jun | Jul | Aug | Sep | Oct | Season (ac-in) |
Average tree fruit water use by month, based on 1972-2002 WSU data. | 1.68 | 4.58 | 7.52 | 9.55 | 7.77 | 4.17 | 2.00 | 37.27 |
Average tree water use by month, with 65% application efficiency. | 2.58 | 7.05 | 11.57 | 14.69 | 11.95 | 6.42 | 3.08 | 57.34 |
Average Pasture/Turf water use by month (85% of WSU tree fruit water use avg. value). | 1.43 | 3.89 | 6.39 | 8.12 | 6.60 | 3.54 | 1.70 | 31.68 |
Average Pasture/Turf water use by month, with 65% efficiency. | 2.20 | 5.99 | 9.83 | 12.49 | 10.16 | 5.45 | 2.62 | 48.74 |
(This table is from the watershed plan, based on the State of Washington Irrigation Guide and supplemented by Washington State Tree Fruit Research data collected in Wenatchee WA.)
(d) Commercial and light industrial: The consumptive amount shall be the amount needed for the specific purpose, as determined by the department and/or the Chelan-Douglas health district.
(9) Since all uses from the reserve will have the same priority date, the following will guide water supply decisions in times of water shortage:
(a) Among the three use categories: Domestic and stock-watering uses will be met first, followed by commercial agriculture and finally commercial/light industrial.
(b) Within each use category, the date of first beneficial use will be used. The use with the earliest date will be satisfied first.
(10) The reservation is created in the context of the year 2025 planning horizon of the watershed plan. Future water supplies may also be available concurrently, using alternative water sources such as storage, reuse and conservation (WAC
173-546-100).
(11) The reservation will be evaluated by the department and the Entiat planning unit no less than every five years: 2010, 2015, and 2020. The allocated and unallocated amounts for each use will be reviewed, as well as the allocated and unallocated amounts for the entire reserve. Modifications to the program may therefore be implemented by rule, if needed.
(12) The department shall notify both Chelan County and the planning unit or its successor, in writing, when it determines that fifty percent, seventy-five percent, and one hundred percent, respectively, of the reservation is allocated. The department shall also issue a public notice in a newspaper of general circulation for the region at the same three junctures.
(13) The department shall require metering and reporting for permitted surface and groundwater allocations from the reservation. If more accurate water use data is needed the department may, after consulting with the EWPU (or its successor) and Chelan County, require metering and reporting for groundwater withdrawals otherwise exempted from permit requirements under RCW
90.44.050. Public water system providers will be required to meter.
[Statutory Authority: Chapters
43.27A, 90.54, 90.22, and
90.82 RCW. WSR 05-16-114 (Order 04-11), § 173-546-070, filed 8/3/05, effective 9/3/05.]