Water is a common topic for farmers and ranchers. Most conversations begin with it: too much rain, not enough rain. Or, did you get any rain? Producers play a unique role to mitigate floods, drought, high rain runoff, and quick melt-out of snowpack through the fields and pastures they manage.

In the Upper Missouri Basin of southwest Montana, eight community-based watershed coalitions are joining ag producers, municipalities, town residents and small-acreage landowners to plan drought resilience. Three rivers — the Gallatin, Jefferson and Madison — merge to form the Missouri River in the Upper Missouri Basin.

“We are seeing warmer temperatures melt out our snowpack earlier,” says Ann Schwend, water planner for Montana Department of Natural Resources and Conservation, “Weather patterns are shifting. This is a headwater region driven by snowpack. We need to change our management strategies to capture that water before it goes by and down the Missouri, where it may increase flood risks for communities downstream.

“I was down in Omaha [Neb.] a couple of weeks ago, where the Missouri is managed primarily for barge traffic, but not flashy systems. In Montana, we have rural ranching landscapes without much built infrastructure. I think here is where one of our best opportunities lies to provide flood mitigation downriver, and aquifer recharging to benefit irrigation and drinking water.”

WORKING GALLERY: The Walla Walla Basin Watershed Council in southeastern Oregon builds infiltration galleries, similar to a septic system, to recharge the shallow aquifer.

Why recharge?
Move across the map straight West, and the Walla Walla Basin in northeastern Oregon coordinates watershed projects through the Walla Walla Basin Watershed Council. Historically in the winter and spring months, the Walla Walla River — a tributary of the Columbia River — flooded the valley. It provided aquifer recharge to the shallow aquifer by soaking into the ground. The water returned through springs to feed tributaries and small streams, and feed back to the Walla Walla. This provided cold water to cool stream temperatures and additional streamflow in summer.

“With settlement, people began to control when water went across the land, and when it stayed in the river,” explains Steve Patten, the council’s senior environmental scientist. “So there was, and continues to be, less [aquifer] recharge in the wintertime because head gates close, and water just moves downriver.

“By about 1900, the river was fully allocated for water rights. So people dug wells to put additional land into ag production. Groundwater level declined with reduced recharge and increased pumping. We have data going back to the early 1930s, and it's been a slow decline for 80-plus years.”

Producers in the Walla Walla Basin also face water pressure from the Endangered Species Act-listed bull trout and steelhead trout. Three irrigation districts in the basin voluntarily agreed to leave a quarter of their water rights in-stream to maintain streamflows necessary for fish habitat. This prompted a large-scale irrigation efficiency program to compensate for water left in-stream.

“This further reduced the amount of recharge because canals were piped,” Patten explains, “and almost all flood irrigation moved to sprinklers, micro-sprinklers or drip lines. Because of high efficiency in irrigation, there is little summer recharge.”

Sprinkle to recharge
Center pivots, hand-line, wheel-line, sprinkler and drip systems all handle water with precision and timing, and are labor-saving. Unfortunately, their mutual side effect is aquifer reduction, with little or no recharge to balance water use.

“Generally, producers don’t put more water on than the crop needs,” Schwend explains. “The plants consume the majority of water put on the field, and the soil profile is not wetted all the way through.

“If water is applied for a longer period, increasing deep soil moisture, the roots are encouraged to grow deeper into the soil profile where they aren't as susceptible to hot, dry days.”

Both Schwend and Patten say pivots and other high-efficiency systems are helpful late in the season when stream flows are low, because they do not divert as much water.

“When everybody flood-irrigated, there wasn't enough water to satisfy all rights,” Schwend recalls. “The streams often dried up. So in the spring, when snowmelt is coming off and flows are high, we’d like producers to think about putting on a little more water through their pivots to saturate the soil profile to hold spring runoff water in the aquifer instead of sending it downstream. It is a bit like soaking the sponge to improve late-season return flows. Of course, legally available water rights, riparian and aquatic species needs must also be part of the equation.”

Recharge basins
In 2004, the Walla Walla Basin Watershed Council began a shallow-aquifer recharge partnership with Hudson Bay District Improvement Co. “We began restoring groundwater levels by simulating what the river used to do,” Patten says of the project, “but in a more controlled manner, conducive to existing irrigation infrastructure.”

The project moves water, on a five-year limited license water right, through irrigation infrastructure not used from December through March. This provides two benefits with one action: reactivating historic channels spread out across the valley to recharge along their lengths, and also when water arrives at the recharge site.

“The infiltration basins are engineered ponds,” Patten explains, “that hold water until it soaks into the ground. The other type, an infiltration gallery, is a modified drain field similar to a septic system with perforated pipes buried 5 to 6 feet underground.

“The pond takes up land year-round. We place them on ‘non-useful’ areas for farming. The infiltration galleries can be installed underneath a [field] access or orchard lane, or in a field corner where farm equipment cannot turn. About two-thirds of our projects are infiltration galleries, as they can operate while maintaining existing land use. We have recorded about an annual 6-inch increase in groundwater level in the areas around our recharge sites.”

Flood advantages
When rivers rise during snowmelt and spring rains, “producers can open their head gates,” Schwend says, “and use existing canal systems that may be there from former flood irrigation, to send water more broadly across the landscape. This mimics nature’s system of catching high spring flows in the aquifer.

“This helps to attenuate downstream floods by lessening the flow and amount of water in our rivers, and creates drought resilience by retaining water in our shallow aquifer for dryness in late summer," says Schwend. "Once the snowpack is out, water is completely dependent on precipitation. We need to think like a beaver: conserve water and store it for later use.”

 Hemken writes from Lander, Wyo.