WSP02112

• File Number: 8278.200
• Description: Title I - Wellton-Mohawk
• Basin: Colorado Mainstem
• Date: 1/1/1987
• Author: W-M D&ID
• Title: Wellton-Mohawk Irrigation and Drainage District - Overview
• Water Supply Pro - Doc Type: Publication

11

X is equal to 1 for normal rainfall years. For the rainfalls in 1976 and 1977 X is estimated to be 0.80 from Tabl~ "11 I, PI' nil,
Irrigation of Agricultural Lands, Number 11 in the sertes Agronomy.

21

The acreage reduction program removed the following citrus from 1975 through 1977:

383 acres Grapefru it
715 acres Lemons
2 ,962 acres Oranges
. Total 4,060 acres Citrus

1,532 AF Cu
3,003 AF Cu
9,775 AF Cu

14,310 AF Cu

3,736 AF Oe1.
6,129 AF De 1.
27 ,929 Af Del.

37,794 AF Del.

1977 Erf.
1977 Err.
1977 Erf.

41t
49t
35t

1977 Erf.

35%

This acreage was added back in to see the effects of citrus removal. The lrrigation efficiency was lncreased by 2.1 I ':r ((~Ilr (1)6.8 -
54.6) and the deep percolation was reduced by 25,644 acre-feet (194,757 - 169,113).

3/ The acreage reduction program moved the fo11owlng citrus from 1975 through 1978:
398 acres Grapefruit 1,592 AF Cu 3,980 AF Del. 1978 Erf. 40t
813 acres Lemons 3,415 AF Cu 7,266 AF Del. 19/11 Erf. 4/~
3,451 acres Oranges 11,388 AF Cu 33,494 AF De 1. 19711 Ef f. 3U
Total 4,662 acres Citrus 16,395 AF Cu 44,740 AF De 1.

.

This acreage was lldrled back in to see the effects of citrus removal. The Irr1l)ation efficiency was incr"cC1scd hy 'lh"1I1 ',I; l"'..rl~nt
(59.2 _ 56.6) and the deep percolation was reduced by 29,802 acre-feet (192,424 - 162,622) as a resull of cilrus ''0'"'' .,1,

An additional 2.0 percent (56.6 - 54.6) lncrease in Dlstrlct efficiencies is thought lo be due to the lrrigalion Err" ;,'nry [onprovemenls
Programs. such as the lrrigat10n Management Services irrigation scheduling program and the Soil Conseryation Servirl', {1nf,lnn lHlprovement
Program. The 1972 - 1976 average irrigation efftciency prior to the acreage reduction program and prior to signifj. .I"! t'Y.I1.111510/1 of
irrigation efficiency improvement programs in the WHI&DD was 54.6 percent.

4/

To show the savings in deep percolation thought to be due to the nofann improvement programs, the following prOCedUi"I' \.lIS ll'ied:

1978 Irrigation efficiency adjusted for effectlve rainfall'
Irrigation efficiency savings due to onfarm improvement programs
Irrigation efficiency without onfarm lmprovements =
Irrigation farm delivery required. 236,240 . 413,007
.~/2
Deep percolation saved = 176,767 AF - 162,622 . 14,145 AF

59.2t
2.0t
'5T.ZI

5/

Effective rainfall to farms was reduced by 1/3 as approximately 1/3 of the District (20,000 acres) had a depth to (Jr.nlllld .....,ller of 0 to 4
feet. Rainfall Is not expected to be conswnpt1vely used if crops are using ground water.

Hote:

The trends in Irrlgatlon efficiencies from 1975 - 1978 tend to support the use of effeclive rainfall to farms. I/ithoul including
effective ralnfall it becomes difficult to explain a drop In project lrrigatlon efficiency in 1978 from 65.1 - 6.1.'/ when 600 acres of
citrus was removed and on farm improvements had been installed on about 8.000 acres. and IMS scheduled over 35,OOll dr:res.