Flynn-Lowney Ditch Acquisition

Flynn-Lowney Ditch Acquisition—Completed

UPDATE—November 1, 2021

The City of Missoula has completed acquisition of the Flynn-Lowney ditch from the Hellgate Valley Irrigation Company. This acquisition was made possible through the generous contributions of our partners at Montana Fish Wildlife and Parks, Trout Unlimited, the Clark Fork Coalition, and the Missoula Redevelopment Agency in the form of grants and private donations, as well as direct cost savings from the Mullan BUILD Project and City of Missoula Water Utility Development funds for the benefit of future water production wells. 

Through this acquisition, the City acquired all water rights and easements associated with the ditch. The City intends to decommission the ditch and transfer water rights to wells for future irrigation. Unused water rights will be transferred back to instream flow in the Clark Fork River. Future projects will remove the diversion structure upstream of Broadway Island, restore the river channel, and protect the river bank and boat ramp from erosion along Silver Park. The ditch easements will remain in place until they are formally released by the City. The City intends to hold these easements for the purpose of conveying water, which may include carrying stormwater from adjacent roads or developments in the future. Landowners who are interested in filling in ditches or repurposing the land for other uses are encouraged to contact the City at or 406-552-6769.



On May 12, 2021, the Public Works & Mobility Department announced that staff had negotiated an agreement with Hellgate Valley Irrigation Company to purchase the Flynn-Lowney Ditch. The purchase is contingent upon City Council approval and the department's ability to raise the necessary funds.

Why does the City want to buy the ditch?

1.  Financial Benefit to Mullan BUILD Project

  • Preserving the irrigation ditches in the Mullan BUILD Project area will be expensive. Large culverts will need to be installed at a cost of about $650,000.
  • The ditches are problematic for storm water management in the Mullan BUILD Project area because they influence ground water and therefore increase the cost of installing storm water infrastructure.

2.  Potential for River Restoration

  • The Clark Fork River could be restored to its natural river function through future projects.
  • Is beneficial for fish and other aquatic species. Some fish are getting trapped in the ditch channel.
  • Diverting water into the ditch can cause issues with bank erosion on the south side of the river adjacent to the Riverfront Trail and the baseball stadium.
  • Improves opportunities for river recreation.
  • Allows City access to deteriorating riverbank so that it can be stabilized and maintained.

3.  Additional Water Rights

  • Water rights not needed for continued irrigation by HVIC shareholders can be converted to instream flow rights to be used in the river to benefit the fishery.
  • Missoula Water plans to work with the airport to drill a test well that will provide data which can be used to develop municipal water supply wells in the Sxwtpqyen (Mullan) Area in the future. Once the data is collected, the well will be turned over to the Airport to use for local irrigation activities, which may include community gardens or other sources of local food production.

4.  Improved Safety

  • Without water actively running through the ditch and culverts, these areas will be safer for children playing near them.
  • The ditch can cause added safety challenges for vehicles that leave the roadway and enter the ditch.
  • By making future modifications to the ditch diversion, the City can improve conditions at the boat ramp across the river from the ditch inlet. Currently, the swift river current can be problematic for people wishing to launch from this ramp.
  • Without the ditch running next to the Broadway Island, it is expected that increased public usage of the island for fishing and other recreational activities will improve safety on the island simply by increasing the number of visitors.

5.  Potential Cost Savings on Other Infrastructure Projects

  • City ownership of the ditch would reduce the cost of future surface transportation projects that cross the ditch but are outside of the Sxwtpqyen (Mullan) Area. The City would not have to make allowances for the ditch or install culverts at those locations.
  • Land currently occupied by the ditch could become space for other infrastructure, such as housing, trails, and parks.
  • Not having to cover or pipe the irrigation ditch on future transportation or related infrastructure projects along Mullan Road could also be a cost savings.
Why does Hellgate Valley Irrigation Company want to sell the ditch?

HVIC has found it to be increasingly expensive to maintain the ditch and difficult to get water during the late summer, and the number of active irrigators wishing to draw water from the ditch has been declining in recent years.

How will the ditch's current irrigators get the water they need?

Nothing will change this year, but next year, after the City acquires the ditch and the water rights, no surface water will be diverted into the ditch. HVIC shareholders who desire to continue irrigating can use a portion of the funds from the City’s purchase to drill a well on their property, and the City will work with DNRC to provide the groundwater rights necessary to support that irrigation.  

It is anticipated that less than the full volume historically diverted into the ditch will be needed to meet the needs of the HVIC shareholders who desire to continue irrigating using groundwater. This is partly because irrigation from individual wells will require less water to be diverted, as there is little to no loss to ditch seepage or evaporation.   Additionally, because some of the historically irrigated lands have been developed, the full volume of water historically diverted is not likely needed to support current irrigation practices.

How did this purchase agreement come about?

During discussions with ditch owner Hellgate Valley Irrigation Company (HVIC) regarding the Mullan BUILD Project, the opportunity arose for the sale of the ditch to the City. The City then negotiated a price with HVIC and entered into a purchase agreement, pending Council approval and funding availability.

Will converting surface water rights to groundwater rights significantly affect the Missoula aquifer?

According to multiple modeling efforts, at least 232,000 acre-feet of water (or 7.6 billion gallons) of water flow through the Missoula Aquifer each year. Much of this, on the order of 83%, is leakage from surface water, mainly the Clark Fork River. Based on our estimates, the acreage that is currently in agricultural production being irrigated by water from the Flynn-Lowney Ditch is at most 400 to 500 acres. As a round estimate, irrigation in the Missoula Valley consumes approximately 1 acre foot of water per acre, so the total water consumption for the remaining irrigators is expected to be approximately 500 acre feet—which is clearly sustainable from the aquifer. In addition, the direct connection between the river and the aquifer means the impacts of groundwater diversion are virtually the same as the impacts from surface water diversion.

How much will the ditch cost?

Approximately $990,000.

How will the City pay for the ditch?

The City will use $725,000 from Transportation Impact Fees and Water Utility Development Funds. The remaining $265,000 would need to be raised from other sources, such as grants, private donations, and in-kind services. Funds will be requested in the FY22 budget cycle.

When will the sale be completed?

The City’s offer to buy the ditch allows for a six-month timeline for due diligence, fundraising, and required approvals.

  • Staff will investigate legal and engineering details that are not yet known.
  • The sale will need to go through a public approval process and be authorized by the Mayor and Missoula City Council.
  • Staff will work with public, non-profit, and private partners to find potential funding donors and to apply for grants.

Flynn-Lowney Ditch (in blue)

Flynn-Lowney Ditch - Wide shot

Flynn-Lowney Ditch in Sxwtpqyen (Mullan) Area (ditch in blue, streets/future streets in red)

Flynn-Lowney Ditch - Sxwtpqyen Area

Flynn-Lowney Shareholders Map