RGDSS_Task4_Dist22_Interview

• Title: RGDSS Task 4 - Basin Interviews
• Description: Memo documenting interview with District 22 Water Commissioner.
• Decision Support - Doc Type: Task Memorandum
• Date: 7/2/1999
• DSS Category: Surface Water
• DSS: Rio Grande
• Basin: Rio Grande
• Contract/PO #: C153863
• Grant Type: Non-Reimbursable
• Bill Number: HB98-1189, SB99-173
• Prepared By: Leonard Rice Engineering

• Norton Drain (Main) 150 cfs
• Norton Drain (West) 25 cfs
• Manassa Drainage Ditch 15 cfs
• Mestas Drain No. 1 10 cfs
• Mestas Drain No. 2 10 cfs
Use of drains as a water supply is common in District 22, and occurs by way of direct diversion
(gravity flow). Except for the Norton Drain which discharges to the Rio Grande, the use of water
captured by these drains is not recorded by the District Commissioners because it would not
discharge to the Rio Grande.
The Norton Drain is one of the few drain systems in the San Luis Valley which physically drains
to the Rio Grande. The Norton Drain captures drainage flows from an area between La Jara
Creek and the Conejos River east of the Town of Sanford, and is of particular importance because
of its significance in administration of the Compact. The Norton Drain captures return flows
originating from lands irrigated with water from both the Conejos River and the Rio Grande. As
such, the flows from the Norton Drain are credited toward meeting Compact delivery
requirements of both the Rio Grande and Conejos systems. As originally established, the water
users on the Rio Grande were credited with 100 percent of all flows returning to the Rio Grande
from the Norton Drain. As currently operated, the division of credit is based on actual observed
flows at two gages on the Drain and has resulted in significantly more than 40% being credited to
the Conejos. The Conejos system is credited with flows observed at gaging station ID No.
NORDSCCO, and the Rio Grande system is credited with flows observed at station ID No.
NORDLSCO less the Conejos Credit.
Key Structures
To assist in the development of a surface water model of the Rio Grande as part of the RGDSS,
discussions with District 22 Commissioners included the identification of "key" diversion
structures. Key structures were defined as those that significantly effect water rights
administration in the District. The criteria that were used to identify key structures included:
• total decreed water right amount under the structure (greater than 5 cfs);
• water right priority, either senior or swing rights as identified by the water
commissioner during the interview;
• relatively large amounts of land irrigated under the structure (250 acres and
greater); and
• represented in previous modeling efforts.
A list of all structures within District 22 is provided as Attachment 3. Fora 5 cfs cutoff, 125 key
structures exist in District 22 that represent 100% of the decreed rights in District 22. Also, the
last column of Attachment 3 includes a descriptor that explains why a structure that appears to
meet one or more of the above criteria was not considered key.
Reservoir Storage Rights and Operations
There is one major reservoir in District 22. Platoro Reservoir, with a decreed capacity of 53,571
acre-feet, is located along the upper reaches of the Conejos River, and upstream of all surface
diversion points. Platoro Reservoir is owned and operated by the Conejos Water Conservancy
District (CWCD). The reservoir is located approximately 50 miles upstream of the Town of
Antonito, with a travel time to the Magote streamflow gage of approximately 24 hours
C:Acdss\D22_Mem.doc District 22 Interview July 2, 1999 -Page 4 of 9