WSP03845

• File Number: 8276.450
• Description: McElmo Creek Unit - Colorado River Salinity Control Program
• State: CO
• Basin: Colorado Mainstem
• Water Division: 7
• Date: 3/1/1992
• Title: Monitoring and Evaluation Report for the McElmo Creek Unit of the Colorado River Basic Salinity Control Program 1991 Annual Report
• Water Supply Pro - Doc Type: Annual Report

II. HYDRO-SALINITY MONITORING & EVALUATION

A. 81lJDmRY OJ' BYDRo-SALDTJ:TY IlOlfITORIlfG , BVALUATIOJI:

Durinq the 1991 irriqation season, usable data was
collected from four monitorinq sites and two ET stations. A
fifth site was selected but the monitorinq equipment for
that site did not arrive in time to set up before the
irriqation season started.

At the present time, the software beinq used by the
Grand Junction M&E Team is not capable of reducinq the data
that was collected by the McElmo Creek M&E Team. The
software will be modified as soon as an official M&E
software support person is desiqnated. This M&E software
support person will coordinate any software modifications
with the three M&E Teams in Colorado as all three M&E Teams
use the same software proqrams for data reduction. As soon
as the modifications are made, the data collected durinq the
1991 irriqation season will be reduced for the next McElmo
Creek Unit Annual Report.

1. The rainfall amount that fell durinq the 1991
irriqation season (May 1 throuqh September 30) was 3.3
inches. The ET rate for the same period was 29.80 inches
(Jensen-Raise formula) and was taken from the Extension
service's weather station.

2. The primary crop that was monitored on all sites
was alfalfa or an alfalfa-qrass mixture with a predominance
of alfalfa.

3. Selection of sites with no improvements installed
is very difficult. The fields are irregularly shaped,
fields are corruqated, slopes are not uniform, water may be
delivered to a field by one or more delivery ditches,
tailwater may leave the field at several different points,
and water may flow across the field in several different
directions.

Site #10 - 19.0 acre established alfalfa field. Water
is delivered by earthen ditch into earthen feeder ditches
and then into corruqates. The field was irriqated three
times throuqhout the season with each irriqation lastinq 20-
22 days.

site #11 - 10.0 acre newly established alfalfa field.
Water is delivered by earthen ditch into flex tube with
control qates. This field was used as a demonstration field
for surqe irriqation. A lack of manaqement and
. ..,
understandinq on the farmer's part prevented this '\~ <J~""
demonstration from beinq a complete success. The fiel~~as
irriqated 8 times durinq the irriqation season.