For Wood River Valley residents gearing up to feel a potential pinch in water use this summer, there are ways to soften the effects of drought and conjunctive water management.
Several ideas were offered Friday at a water seminar hosted by the Wood River Land Trust, The Nature Conservancy and University of Idaho Extension at the Community Campus in Hailey.
One of the day’s workshops addressed the topic of drought-tolerant lawns, and how to install them correctly. This process involves eradicating existing bluegrass species and replanting a native mix that can tolerate drier conditions. Patti Lousen, project coordinator at the Land Trust, presented a video detailing some of the ways in which homeowners can remove their sod (the video can be viewed on the organization’s website).
There is a range of methods to consider when starting the conversion process. Residents can choose to tarp their lawn for an entire summer; cut their grass short and cover it with layers of wet newspaper; cut and flip the sod; or completely remove the existing sod and bring in new soil.
Lousen also discussed the use of Roundup to kill off an existing lawn.
“[At WRLT] we chose to kill it with Roundup and then reseed it,” said Lousen.
The chemical is absorbed quickly by the grass, and breaks down quickly. It often takes several applications in order to completely eradicate the existing bluegrass. For more information about killing off water-dependent bluegrass, the organization has made educational material available on its “Trout Friendly Lawns” webpage.
Restoration ecologist Steve Paulsen, from Conservation Seeding and Restoration Inc., also gave a how-to in replacing existing Kentucky bluegrass lawns with drought-tolerant grass. Advocating “native restoration,” Paulsen spoke about the importance of using a mix of locally native drought-tolerant grass seed, on soil that is completely devoid of any bluegrass species. Overall, Paulsen stressed the importance of making sure the unwanted grass is eradicated completely.
“Kill it dead, or remove it,” Paulsen said, since any leftover bluegrass will essentially return and take over newly planted native species. Once a clean slate is achieved, the soil can be planted with a native mix, via seeding or planting of new sod. Those in the market for native grass seed should make sure they are buying a mix with a high percentage of “live seed,” and that the species is regionally based, he said.
The process of switching to a new, drought-tolerant lawn takes time, patience and investment, the speakers said. A careful watering regime is necessary in the first few weeks. But the benefits of making the conversion can be many. Native lawns can require up to 50 percent less water to maintain and less mowing, rewarding homeowners with time and money. Less vegetative material deposited in landfills and significantly less wasted water are two other reasons Paulsen identified.
“As a society, there are lots of reasons to engage this,” he said.
The seminar also offered a workshop regarding irrigation systems. Irrigation auditor Kodi Farnsworth presented a variety of techniques that can save homeowners from overwatering their property anywhere from 20 to 60 percent.
One of these techniques involves employing state-of-the-art irrigation tools such as sensors and controllers that can monitor the exact needs of the homeowner’s plants and soil. Knowing the existing type of soil and plant root depth are important factors to be aware of when watering. Over-saturation can cause disease among plants, Farnsworth said.
“When done properly, you can cut water usage significantly,” he said.
Residents can also decrease their water use by updating sprinkler heads, and making sure they achieve uniform water distribution.
“Poor uniformity leads to longer run times,” Farnsworth said.
Sprinkler type, spacing, flow rate and water pressure are among some of the key factors in making an irrigation system operate correctly, for maximum water efficiency and health of the landscape, he said.
For homeowners interested in finding out how efficient their system currently is, scheduling an irrigation audit can help them discover how to better care for their landscaping. Depending on the size of the property and other controlling factors, the cost of revamping one’s irrigation system can be high. Those with less acreage may not notice the return in their pocketbook for several years.
“But sometimes doing the right thing is doing the right thing,” Farnsworth said.
Groundwater model on schedule
Almost a year after it was begun, a model of groundwater flow in the Wood River basin is on schedule to be completed by the end of 2015, Idaho Department of Water Resources project director Sean Vincent told people attending a water seminar in Hailey on Friday.
Tim Luke, water compliance bureau chief for the Idaho Department of Water Resources, said the groundwater flow model will help determine the extent of injury suffered by a surface water-rights holder in the event of a call on a groundwater user. The degree of injury helps to determine whether the call is justified.
Jim Bartolino, a hydrologist at the U.S. Geological Survey’s Idaho Water Science Center in Boise, said the Wood River aquifer is composed of sand, gravel and clay, and sits on top of basalt bedrock. It is 20-30 feet deep near the headwaters of the river, about 100 feet deep near Ketchum and about 350 feet deep under the Bellevue Triangle.
Most of the aquifer is interconnected—that’s called the “unconfined” part. But a separate part, the “confined” area of the aquifer, sits deeper down and is under pressure; water in wells drilled into that section rise to the level of the highest point in the aquifer, not to the level of the surrounding water.
Most of the aquifer discharges into Silver Creek, though some flows into the Big Wood River in the vicinity of Stanton Crossing.
Wells suck water out of a cone-shaped area that deepens and widens as more water is pumped out. With enough pumping, the wells can drain water from the river itself.
“Every well in the Wood River Valley is affecting surface water to some degree,” Bartolino said.