WSPC02454

• File Number: 8283.200
• Description: Colorado River Basin-Colorado River Computer Models-Colorado River Decision Support System
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 12/1/1995
• Title: San Juan River Basin Modeling-San Juan Special Water Right Operations
• Water Supply Pro - Doc Type: Report/Study

1)OO~9D

90 % are assumed to return above the USGS Stream Gage No. 0936500.

The Hammond Ditch is the principal feature of the USBR's Hammond Project. The United
States holds a New Mexico permit for 23,000 acre,feet with a 1955 priority date just junior to the
water right owned by BHP (used at the Four Corners power plant) and just senior to the water
rights for Navajo Reservoir. The ditch can divert at rates of up to 90 cfs for irrigation of an
estimated 4,000 acres on the south side of the San Juan River between Navajo Reservoir and
Farmington. The Hammond ~itch does not have a specific storage entitlement in Navajo Reservoir,
but it is acknowledged that releases from the reservoir have enhanced the water diversions at the
Hammond Canal. For the CROSS WRPM, the average annual demand by the Hammond Project
is assumed to be 10,000 acre-feet, based on recommendations of the USBR. The monthly
diversion demands shown in Table 1 are recommended. In the CROSS WRPM, all of the irrigation
return flows are assumed to return above the USGS Stream Gage No. 0936500.

The Fruitland Irrigation Canal is operated by the Bureau of Indian Affairs (BIA) and is used
for the irrigation of about 3,600 acres of land on the south side of the San Juan River between
Farmington and the geologic "hogback". The canal is operated as a senior demand on the San
Juan River and has a capacity of about 87 cfs. For purposes of the CROSS WRPMi the average
annual demand is assumed to be approximately 19,900 acre,feet. distributed monthly as shown
in Table 1. In the WRPM, 55% of the irrigation return flows are assumed to return above the
diversion for the San Juan Power Plant, 40% above the Hogback Canal and 5% above the USGS
Stream Gage No. 09379500.

The Jewitt Valley Canal is a small irrigation system that irrigates approximately 1,200 acres
on the north side of the San Juan River just upstream of the geologic hogback. The structure
holds a New Mexico permit for 31.71 cfs with a 1879 priority date. In accordance with
information provided by the USBR, the average annual demand is assumed to be about 6,300 acre,
feet, distributed monthly as shown in Table 1. All of the irrigation return flows are assumed to
return above the headgate of the Hogback Canal.

The Hogback Canal is a another system operated by the BIA for the benefit of the Navajo
Nation and irrigates approximately 9,060 acres of land on the north side of the San Juan River
from the geologic hogback to a point about 15 miles northwest of Shiprock. The ditch is operated
as a senior water right on the San Juan and has the ability to divert up to 300 cfs. Based on
information provided by the USBR, the average annual demand for the Hogback Canal is assumed
to be about 80,600 acre-feet per year, distributed monthly as shown on Table 1. Note that for
this structure, the demands during the summer irrigation months of June, July and August are
assumed to be the full capacity of the canal at 300 cfs. For the CROSS WRPM, all of the irrigation
return flows are assumed to return above the USGS Stream Gage No. 09379500.

The irrigation return flows from these major structures all accrue to the San Juan River and
for the CROSS WRPM, the locations were determined as described in the previous text. The
return flow locations were estimated using topographic contour maps and the relative locations
of the irrigated areas with respect to the headgates of the other modelled structures.

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