Tin Cup Creek

In the spring and early summer, irrigation water is supplied from water rights that the District has on Tin Cup Creek water. This water is called direct flow water that would normally be in the creek from snow melt, rainfall, etc. It does not include water stored in the lake. Water rights in Montana are based on the prior appropriation doctrine meaning that the first in time is the first in right. The District has two water rights (700 and 100 miners inches) established in 1889, and one each established 1908 and 1914 (200 and 360 miners inches, respectively). The 1889 water rights for example are the 7th water right on the creek, meaning that 6 other users' water rights have a higher priority (were recorded earlier). These water rights are referred to as senior to ours, while ours are junior to theirs. When the flow in the creek decreases to a level that cannot supply the 1st to the 7th water right then the District must decrease the diversion into the ditch to maintain flow for the 1st to 6th priority water rights holders. At this time however the District can open the head gate on the dam and supplement the flow with lake water. The District owns all of the water rights for lake water (see below).

Tin Cup Lake

Tin Cup Lake is used to store late season irrigation water for use in supplementing in-stream flow when it becomes too low, usually in late July. Prior to 1998 when the dam was breached, the lake capacity was 2000 acre feet. The rebuilding of the dam has now restored the lake back to its original capacity. Of this, 400 acre feet is allocated to
maintaining late season in-stream flow as per the agreement with the Montana Water Trust, leaving 1600 acre feet available for District
member's use for irrigation. This represents a 76% increase over the
amount available after the breach but prior to rebuilding of the dam.

Of the 1600 acre feet, 7% is lost in Tin Cup Creek prior to the District's diversion and 12% is lost in the ditch due to seepage and evaporation.

Assuming an average daily use is 40 acre feet per day, lake water will
provide an additional 18 days of irrigation at full allocations for those
irrigating on a daily basis (or 9 days at double the allocation for those
irrigating on a bi-weekly basis). Following this, irrigators will be required to reduce flows to 50 percent of their allocation. Irrigation water will then be available at these reduced flows approximately another 5 days.

A miners inch is a unit of water measurement originating with placer mining in the 19th century.
1 miners inch =11.22 gallons per minute
1 miners inch = 1/40 cubic foot per second.
20 miners inches for a 24-hour day = 1 acre foot

*The definitions vary from state to state. These hold for Montana..

A Brief History

Tin Cup Water and Sewer District

Located just west of Darby, Montana in the Bitterroot Valley, the Tin Cup Water & Sewer District (the District) provides water from Tin Cup Creek and Tin Cup Lake to numerous water users for both irrigation and livestock-watering purposes. The District operates and maintains one of the primary diversion ditches on Tin Cup Creek, historically known as the McIntosh-Morello Lowline Ditch, but now simply referred to as the Tin Cup Ditch. The District also operates and maintains a storage facility at Tin Cup Lake, located at the headwaters of the Tin Cup Creek drainage within the Selway-Bitterroot Wilderness.

The Bitterroot Valley in southwestern Montana was one of the earliest developed agricultural valleys in Montana, with Ravalli County records indicating irrigation water rights appropriated on Burnt Fork Creek, for example, as early as 1852. See Ravalli County Water Resources Survey (1958). On Tin Cup Creek, irrigators were constructing ditches to divert water to their properties as early as 1883.

As the Valley developed, limited supplies of water and a growing number of competing users meant that supplies on most tributary streams were fully appropriated – or “spoken for” – by irrigators prior to the 20th Century. In other words, demand had outpaced the supply, and there was not enough water to allow all irrigators to irrigate for the full season. By the early 1900s, the “natural flow” of Tin Cup Creek had been fully allocated to various water users. Therefore, to provide additional supplies of water for late-summer uses, enterprising irrigators constructed a dam at the outlet of Tin Cup Lake to raise the water level and capture snowmelt and other precipitation during the late fall, winter, and early spring months.

The Tin Cup Dam was originally constructed in 1906 and was raised in 1932. Thus, there are two water right claims associated with the dam: one with a priority date of August 20, 1906 associated with the original dam capacity of 1,500 Acre-Feet, and another with priority date of August 17, 1931 associated with the enlargement in 1932 that added an additional 500 Acre-Feet of storage, for a total storage of 2,000 Acre-Feet. The District owns all water rights associated with stored water in Tin Cup Lake, which allows it to provide additional water for District users for late-season uses.

Without a formal, state-controlled system for claiming water rights and with growing disputes between competing water users, most streams in the Bitterroot Valley had gone through some stage of adjudication in the Court system by the early 20th century. Tin Cup Creek was no exception. Like all senior water rights on Tin Cup Creek and its tributaries, the water rights now held by the District were decreed by the Ravalli County District Court in 1933. See Decree in Case No. 4964, Cummins et al. v. McIntosh-Morello Orchards Co. et al. 4th Judicial District Court of Montana (June 23, 1933). The water rights now owned by the District (both direct flow rights and storage rights) were originally decreed to several different parties by the District Court, including the McIntosh Morello Orchards Company, the Ford & Hollister Ranch, Inc., the Tin Cup Irrigation Co., and Roy Ostegren.

A significant portion of the land that now encompasses the District was once owned by the McIntosh-Morello Orchards Company. In the early 20th Century, the McIntosh-Morello Orchards owned nearly 2,700 acres including roughly 1,200 acres of apple and cherry orchards (including the “Lake Como Orchards” and the “University Heights Orchards”) and about 1,500 acres of general farm land. The Company developed several “planned communities” designed by famed architect Frank Lloyd Wright, with plans to subdivide the Company’s property and market it for sale (at a tidy profit) to professors, academics and other white-collar workers from the Midwest. See Dorothy Zeisler, History of Irrigation and the Orchard Industry in the Bitterroot Valley (1982). During its tenure, the Company operated and maintained the Tin Cup Ditch, the dam at Tin Cup Lake and the associated water rights. However, blight, lack of farming experience, poor financial planning and other factors eventually lead to the failure of the McIntosh-Morello Orchards Company, and their lands were sold off to various individual farmers and ranchers.

The Tin Cup Water Company was formed in 1952 for the purposes of maintaining and enhancing the Tin Cup Ditch and to distribute water from Tin Cup Creek and Tin Cup Lake to the company’s shareholders and other water users who by contract had the right to receive water diverted through the Ditch. See Ravalli County Water Resources Survey, pg. 63 (1958). The Company was also formed to provide for the ongoing costs of construction, maintenance and distribution on the Tin Cup Ditch. Id. Original stockholders to the Tin Cup Water Co. included W.H. Brandbo, Catherine Johnson, Howard Buhler, Weldon Buhler, George (Jerry) Else, Boyd Gibbons, Jr. and Clifford Buhler.

After the formation of Tin Cup Water Co., Montana began its statewide adjudication of all “historical” (pre-1973) water rights and all water users with water rights older than 1973 were required to file on their claims by 1982. Prior to adjudication by the Montana Water Court, the water rights now held by the District were transferred to the Tin Cup Water Co. by quitclaim deed in 1994 and 1995. These deeds were recorded with the Ravalli County Clerk & Recorder. The Tin Cup Water Company was dissolved in 1997, and the District was formed that same year and assumed all right, title and interest in the Company’s water rights.

Much like its predecessor the Tin Cup Water Company, the District was formed to benefit water users (both District members and contract users) of the Tin Cup Ditch and to provide for the ongoing costs of improvements, maintenance and distribution on the Ditch. The District has a “service area” of over 2,200 acres that it is allowed to irrigate; however, a maximum of 1,607 acres within the larger service area may be irrigated in a single irrigation season. Almost the entire District diversion system has been updated and improved in recent years in order to improve the efficiency of the system and provide more water to District users. Examples of improvements include: a telemetry (remote) controlled headgate at Tin Cup Lake, improved diversion and fish screen at the Tin Cup Ditch, state-of-the-art flow monitoring system in the Ditch, ditch lining projects to prevent waste and seepage and more. To learn more about District improvements, visit the related pages on the District’s website.