SPDSS_Task5_KeyStructure_BoulderLarimerDitch

• Title: SPDSS Task 5 - Key Structures, Boulder Larimer Ditch System
• Description: The Boulder Larimer Ditch System has been identified as a key structure for the South Platte Decision Support System ‎(SPDSS)‎ consumptive use and surface water modeling efforts. The purpose of this Task 5 memorandum is to document physical, legal, and operational aspects of those key structures identified.
• Decision Support - Doc Type: Task Memorandum
• Date: 10/28/2004
• DSS Category: Surface Water
• DSS: South Platte
• Basin: South Platte
• Contract/PO #: C153954
• Grant Type: Non-Reimbursable
• Bill Number: SB01-157, HB02-1152, SB03-110, HB04-1221, SB05-084, HB06-1313, SB07-122
• Prepared By: Leonard Rice Engineering

believed to be accurate. However, this information should not be relied upon in any legal
proceeding.
SYSTEM OVERVIEW
The Boulder Larimer Ditch Company is a major irrigation ditch on the Little Thompson River in
Water Division 1, Water District 4. The Boulder Larimer Ditch Company was originally
incorporated as the Boulder Larimer County Manufacturing and Irrigation Company in 1875
with 1,000 shares of stock. Direct flow water and transbasin water supplies are conveyed for
direct irrigation uses and for storage in Ish Reservoir via the Boulder Larimer Ditch, located on
the south side of the Little Thompson River below the Town of Berthoud. In 1905, the New Ish
Ditch Company was formed to support the enlargement of Ish Reservoir to deliver water to
irrigators located below the reservoir, near Johnstown. The two companies operate under
separate boards of directors yet share the reservoir feeder ditch and storage space in Ish
Reservoir, as outlined in a 1905 agreement between the two companies. Irrigators holding the
600 shares of stock in the New Ish system generally use this storage water to supplement water
supplies provided by the Consolidated Supply Ditch Company and/or the Highland Ditch
Company, both of which are based to the south in the St. Vrain River basin. In the late-1990s, the
only change of use of ditch company stock occurred, involving 12 shares that were adjudicated
to support municipal uses at the Big Elk Meadows subdivision near Pinewood Springs, located
north and east of the Town of Lyons.
Key structures identified in the Boulder Larimer Ditch System are as follows (with structure
name form Decision Support System HydroBase database in parentheses, if different):
1) Boulder Larimer Ditch (Bould Larim Co Irr Mfg D)
2) Ish Reservoir (Boulder Larimer Reservoir)
These infrastructure components are owned by the Boulder Larimer Ditch Company (aka Old Ish
Ditch Company):
Boulder Larimer Ditch Company
Berthoud, Colorado 80513
Phone: [phone]
The location of the Boulder Larimer Ditch system is shown on Figure 1.
Boulder Larimer Ditch Memorandum.doc 2 of 11 October 28, 2004