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City to acquire water right to ensure future growth
The city of Mountain Home has taken a major step that, if approved by the state, would guarantee the city's water supply for nearly two more decades.
The city last week signed an agreement, and put down $25,000 in earnest money, to acquire 1,800 acre feet of water per year from the existing mid-level aquifer. One acre-foot represents 325,850 gallons of water.
State officials lauded the move as "highly responsible," since the action does not seek an additional water right on the already overstrained aquifer, but rather is an acquisition of an existing water right.
City officials, looking at the existing growth of the city and the increasingly tight water supplies available in the area, decided that acquiring the right now would solve problems in the long run.
The city will pay $775,800 total for the right, which currently is assigned to a property near the airbase. It will not, however, create a new "diversion point" for the water, meaning no new wells will be drilled on the property where the right was obtained. Instead, the city will use its existing diversion points -- the wells in the city -- to take the water from the aquifer. On the old site, the water had been used to grow hay.
Perhaps most importantly, the water right, actually two specific water rights that the city is attempting to acquire, has priority dates of 1964 and 1966. Those are in the oldest 20 percent of the groundwater rights available. That's important because, if at any point in the future some groundwater rights would have to be curtailed or restricted, newer rights would be cut back first, before older rights such as the city is purchasing would be restricted.
Based on an anticipated annual population growth of 3.5 percent, the new water rights would provide enough water for the city to grow through 2022. That would represent approximately 1,000 new houses.
"This is more water than what our pumping capability can do right now," said city councilman Tom Rist, who along with councilman Rich Urquidi and Mayor Joe B. McNeal, were present at the signing of the agreement for the rights.
When asked how tight the water availability situation is at present, Rist replied: "It's ugly. Elmore County is probably one of the three worst situations in the state."
Because the point of diversion, the site where the water is drawn by wells from the aquifer, is being changed from the existing property to the city, the change in the rights must be approved by the Idaho Department of Water Resources. If no protests are filed, the right could be transferred in just a few months. If protests are filed, it could take up to a year or more before approval (or denial) is granted.
In looking at the long-term growth of the city, city officials said they expected that new growth would help pay for some of the future costs.
"The city is trying to put into place a water rights plan so that either new growth would bring its own water rights with it, or it would reimburse the city for having purchased this water right," said James Bledsoe, an engineer for Keller Associates, Inc., of Boise, which is serving as a consultant to the city on its water needs.
"The problem" Bledsoe said, "is that the local aquifer is over-appropriated. IDWR has issued water rights in excess of capacity" for the mid-level and deep aquifer in the area, he said. Most wells are drilled to the mid-level aquifer, which varies in depth but typically is 400-500 feet deep. The deep aquifer is nearly 1,000 feet lower, making drilling to that depth economically prohibitive for most people, and the shallow aquifer, which can be hit at as little as 20 feet, is so variable in its supply, because it's based on surface water conditions, that it's not reliable.
The current water right held by the city, which it is not utilizing fully at present, allows a diversion rate of 9,200 gallons a minute of water to be pumped from the aquifer. The new right would add an additional 3,285 gallons per minute. The city currently has seven wells available to pump water, but only about half are used in the winter, when no one is watering their lawns.
"Water is the lifeblood of a community," Bledsoe said. The city's purchase of the water right "means you secure a lot of growth potential," he added, noting the new right would allow the city to essentially double in size before it began facing additional water supply shortage problems.
Bledsoe said that the city could simply apply for a new water right, "and no city has ever been denied one," he said, "but it's not the responsible thing to do. This way, its safer from future curtailment."
Groundwater supplies are a source of growing concern in Elmore County. Surface water provides only a fraction of the water needed in the county, and is dependent on snowpack and reservoir capacities. As the county enters its eighth year of expected drought conditions, those supplies have been dwindling.
But so has the aquifer.
In the western part of the county, near the Cinder Butte area, a critical groundwater area has been established by the state that has imposed major restrictions on groundwater use and for all practical purposes has curtailed any new growth in that area.
IDWR also is no longer approving any new groundwater rights for irrigation purposes in that area, and any forced curtailment of water rights could impact an estimated one-half of the groundwater irrigated acres in the area.
And in the area between Mountain Home and the airbase the groundwater level has been declining, on average, one to two feet per year for at least the last 35 years (although there are some isolated areas where it hasn't declined).
Last year, IDWR estimated that 73,600 acre-feet of water was being withdrawn each year from the aquifer, but the "recharge" rate, the rate at which groundwater is replenished by various means, such as water percolating down from the surface, was only 42,700 acre-feet.
That means the aquifer has been "overappropriated" by more than 40 percent.
"Personally," Bledsoe said, "I wouldn't be surprised if IDWR limited domestic water rights in the future."
Each new home built in the area is granted a water right of 13,000 gallons a day, or enough to irrigate one-half acre of ground (usually that is the more restrictive number). But IDWR already is considering reducing that right to somewhere in the vicinity of 8,000 gallons a day.
And, it's also considering creation of a water district for all of central and western Elmore County. IDWR, concerned about the continuing drop in the groundwater, has been threatening to do that for several years, but has been hoping instead that the local Groundwater Advisory Committee would come up with a plan on its own, rather than a state-imposed plan. Although it has taken eight years, that committee is apparently close to issuing a draft plan for public comment for the management of the local aquifer.
A legislative committee, the Expanded Natural Resources Interim Committee Mountain Home Working Group, also has been looking into the problem and in December issued its own set of recommendations, "which we're going to have to look at and act on," said Gary Spackman, who supervises water issues in this part of the state for IDWR.
The interim committee noted that opportunities for recharge or water savings in the Mountain Home Basin "are limited," and diverting some water from the South Fork of the Boise River, Bennett Creek, or the Snake River, to assist with the recharge would run into the problem that the water rights on those surface waters also are fully appropriated, and it would be expensive to obtain those rights -- perhaps prohibitively so.
The committee has recommended a net reduction of approximately 30,900 acre-feet per year in groundwater withdrawals "sufficient to arrest, or at least significantly slow the declines in water levels in the regional aquifer."
It also recommends changing the boundaries of the Cinder Cone Butte Critical Groundwater Area and the Mountain Home Groundwater Management Area, and asks the legislature to approve an "umbrella aquifer management authority" to manage the aquifer.
It recommends creation of a water district for the Mountain Home area. "While regulation should not be immediately contemplated," it said, the district would "measure and report the diversions of water to ensure adherence to limitation of the water rights."
It also calls for a Conservation Reserve Enhanced Program for the area to take some irrigated lands out of production (something the city's acquisition of the airbase-area water right would do), and recommends adoption of water conservation measures by local governments "including incentives for low-water-use landscaping."
Finally, it suggested further study of possible means of diverting surface water to help recharge the aquifer, but noted a number of difficulties that would have to be overcome, both in terms of acquiring water rights and finances.
"I think the city is recognizing there is a finite supply of water," Spackman said, "and is protecting itself by acquiring an older right" while at the same time is helping protect the aquifer by not seeking a new right.
"They're protecting the public by ensuring a water right that won't be curtailed," he said, "and not placing an additional burden on the aquifer."