Robbing our groundwater savings accounts for today’s needs — The Mountain Town News

December 16, 2014

From The Mountain Town News (Allen Best):

Dick Wolfe, Colorado’s state water engineer, recently defined “sustainable groundwater supply” as one that is managed so that recharge matches withdrawals in a way to avoid long-term depletion of the aquifer.

By that definition, Colorado is not, for the most part, using its aquifers sustainably. Nor, for that matter, is most of the nation or world.

That much was made clear at a conference on Dec. 4 that was conducted by the American Ground Water Trust. Andrew Stone, the organization’s executive director, said 14 percent of all water used to irrigate crops in the United States comes from mining groundwater aquifers. This started slowly, but picked up as pumps and cheap energy became available around the end of World War II. The extraction by farmers and cities of water above the rate of recharge is now close to 400 cubic kilometers.

“We are robbing our savings account,” he said.

Driven by population growth and the uncertain effects of climate change, pressures on these subterranean savings accounts will only worsen, he said. This is not inevitable. He cited Los Angeles, which after World War II turned to groundwater exploitation to satisfy growth. “In the 1960s, it was pretty clear that the LA Basin was cruising for big trouble,” he said. But unsustainable exploitation has ended.

Problems of groundwater exploitation are common in many areas of the country, but solutions must be forged locally, “aquifer by aquifer, region by region,” said Stone.

Sobering statistics

The day was littered with fascinating statistics. Jeff Lukas, of the Western Water Assessment, explained that of the 95 million acre-feet that falls on Colorado, only 14 million acre-feet end up as runoff in our streams and rivers. The remainder, 80 million acre-feet, evaporates or gets drawn back into the atmospheric through transpiration. Together, the two are called evapotranspiration, or ET.

This rate of ET will almost certainly rise as the atmosphere warms. In the last 30 years, temperatures have ratcheted up 2 degrees Fahrenheit. Climate models forecast another increase of between 2.5 to 5 degrees by mid-century in Colorado. By mid-century, the hottest summers of the last 50 to 100 years will become the norm.

Too, everything from corn to urban lawns will need 5 to 30 percent more moisture during the longer, hotter summers—assuming precipitation does not increase.

How much precipitation will change as the result of elevated greenhouse gases in the atmosphere remains a mystery. Unlike temperatures, average precipitation in Colorado has not changed appreciably in the last three decades. Climate models have been clear about increasing temperatures, but precipitation remains a flip of the coin.

However, warming alone will drive changes, “pushing both the supply and demand in the wrong direction,” said Lukas. Increased evapotranspiration will reduce runoff and the amount of moisture available to percolate into soils and down into aquifers. Spring runoff has already accelerated and will come one to three weeks earlier.

Bottom line: Hotter temperatures will drive farmers to suck up more subterranean water. If anything, aquifers will recharge more slowly.

Wolfe, in his turn at the microphone, had even more statistics: Of Colorado’s 16 million acre-feet, 10 million acre-feet flow out of state, mostly as a result of compacts governing the Colorado and other rivers.

“That leaves us about 6 million acre-feet in Colorado to use,” he said. This surface water provides about 83 percent of water used in Colorado, and the other 17 percent comes from aquifers, which are tapped by 270,000 wells.

Of this groundwater, 85 percent goes to agriculture, for more than 2 million acres, but there’s also a strong urban component. One in five Coloradans get their water from wells. Most prominent are Denver’s southern suburbs in Douglas County.

Denver’s South Metro

South Metro has been a poster child for living in the moment. It’s affluent and rapidly growing. Served almost exclusively by wells, the residents of Castle Park, Parker and adjoining areas comprise about 6 percent of Colorado’s population but command 30 percent of income. Today’s population of 300,000 residents is projected to grow to 550,000 by mid-century.

Wells have been dropping rapidly, five feet in just one year in Dawson, one of the aquifers.

Eric Hecox, executive director of the South Metro Water Supply Authority, explained that it was always understood that wells would not last forever. The area had hoped to benefit from Denver’s Two Forks Dam, which was to have been filled primarily by expanded diversions from the Western Slope.

Two Forks was sunk by environmental concerns in the early 1990s. Inconveniently, Douglas County surged in population, routinely landing in the top 10 of the nation’s fastest-growing counties, a distinction that only lately has abated.

Other projects have also nudged the South Metro area off its exclusive dependence on groundwater, but even collectively they do not provide the answer. Hecox called for continued efforts to pinpoint needs while creating a new generation of partnerships and infrastructure.

Can South Metro’s needs for sustainable water supplies be answered by building a giant pipeline from Flaming Gorge Reservoir, on the Utah-Wyomng border? That idea was proposed in 2006 by entrepreneur Aaron Million, and then echoed by Frank Jaeger, the now-retired director of Parker Water and Sanitation District.

Hecox said the Bureau of Reclamation study about water availability from Flaming Gorge has not been completed. That study will provide the 14 members in Hecox’s South Metro coalition “base information on which to decide whether we want to pursue it any further,” he said.

Two key agriculture areas

Two agriculture areas in Colorado that rely upon aquifers are in arguably worse shape. The San Luis Valley has an area called the Closed Basin. With the arrival of electricity to farms in the 1950s, large-scale pumping began and, for a number of years, all went well, said Steve Vandiver, general manager of the Rio Grande Water Conservation District.

Despite earlier hints of problems, the magnitude of over-pumping started becoming apparent in 1998. One million acre-feet had been pumped from the aquifer above the amount of recharge. Figuring out what to do took time and negotiation. “There have been rocks thrown from every quarter,” he said.

The plan now in place has cut pumping by 30 percent during the last three years. The amount of irrigated acreage has declined from 175,00 to 150,000 acres. Water use on those remaining acres has been reduced in some cases by planting different, less water-intensive crops and also by using different irrigation methods.

Up to 300,000 cubic feet per second of water continues to be pumped on the fields in the Closed Basin on hot summer days.

And the Ogallala….

The Ogallala Aquifer is perhaps America’s best-known story of groundwater depletion. It extends over parts of eight states, from Texas to South Dakota, and the aquifer has declined at a shocking rate in several of those states, but more slowly or not at all in places, especially the Nebraska Sand Hills.

The Republican River Basin of northeastern Colorado is emblematic of many. Farmers working with local districts and the state government have been shifting the paradigm. Whether they’re shifting rapidly enough is an open question.

The river and its tributaries originate on the high plains, gaining no benefit from mountain snowpack. Yet this region had 480,000 irrigated acres in an area where annual precipitation is only 17 inches a year.

The key: mining the Ogallala. In the late 1970s, Colorado began taking action to slow the unsustainable over-pumping, but more radical measures were triggered by the need to comply with the interstate compact governing the river shared with Nebraska and Kansas. Colorado was forced to release more water downstream.

It did this partly by abandoning Bonny Reservoir, eliminating the evaporative losses. At greater expense, the district constructed an expensive pipeline and now pumps water—ironically from wells—to release into the Republican River at the state line. The total cost of the pipeline and the purchase of water rights was $48 million.

Much is being done to steer the Titanic away from the iceberg of exhausted aquifer water, but Deb Daniel, general manager of the Republican River Water Conservation District, suggested the magnitude of the challenge when she said: “Sustainable, that’s a scary word where I come from.”

(For a story I recently wrote about the Ogallala in Colorado, see the Headwaters Magazine website).

Wells along the South Platte

Unlike everything else said in the day, several speakers argued that not enough pumping has been occurring along the South Platte River. Their solution: more reservoirs and also more acreage returned to production.

Robert A. Longenbaugh, a consulting water engineer, pointed to 400,000 acre-feet average annually flowing into Nebraska above the compact requirement. “I call that a waste of water,” he said. At the same time, he and others pointed to reports of basements in Weld County getting flooded because of rising groundwater levels.

Even in the 1960s, a Colorado law was adopted that formally recognized that aquifers and surface streamflows comingled waters . In other words, if you have a well a quarter-mile from the South Platte River at Greeley and pump it, that might mean less water in the river as it flows toward Fort Morgan.

The drought of 2002 forced the issue, and in 2006 the state put well irrigators into the priority system. In 2012, a hot and dry year, many wells had to be shut down and corn and other corps left to dry up. Longenbaugh called for changes.

“Strict priority administration of ground and surface rights does not maximize the beneficial use,” he declared. Instead, he wants to se a “real-time management of the South Platte, to monitor surface and ground water and “make short-term decisions” looking out six months ahead while still maintaining the priority-appropriation doctrine that is the bedrock of Colorado water law.

A panel of state legislators later in the day acknowledged varying degrees of agreement with Longenbaugh’s statement. Sen. Mary Hodge, a Democrat from Brighton, described a pendulum that went from “too lax” to now one of being “too stringent.”

Sen. Vicki Marble, a Republican from Fort Collins, described the situation as deserving of an “emergency measure.” She later added: “We should let people self-regulate,” while suggesting that the wells should be allowed to pump. “It’s their right,” she said.

More groundwater coverage here.


Lake Pueblo State Park: Proposed new pumping rules to be discussed November 17 #ArkansasRiver

October 17, 2014

Arkansas River Basin -- Graphic via the Colorado Geological Survey

Arkansas River Basin — Graphic via the Colorado Geological Survey


From The Pueblo Chieftain (Chris Woodka):

Groundwater rules that could help certain farmers avoid some of the cost of water court applications are being considered for the Arkansas River basin.

“We’re not necessarily committed to this idea, but it may have benefits,” Water Division 2 Engineer Steve Witte told the Southeastern Colorado Water Conservancy District board Thursday. “The public needs to weigh in.”

The first chance to do that will be at a meeting at 1 p.m. Nov. 13 at the Lake Pueblo State Park visitors center auditorium.

The rules would apply to water replacement plans for post-1985 pumping, new uses for wells drilled prior to 1985 or new wells. They would provide an administrative alternative to water court, which can be too expensive for individual water users to navigate.

Witte reviewed the history of legal issues surrounding wells in the Arkansas Valley, including the 1972 attempt to reconcile surface and groundwater use, the Kansas v. Colorado case filed in 1985 that led to the 1996 well rules and the Simpson v. Bijou decision by the state Supreme Court in 2003 that took many well augmentation plans out of the hands of the state engineer.

“Decreed plans for augmentation costs have been so prohibitive in the South Platte that thousands of wells remain shut down to this day because of Simpson v. Bijou,” Witte said. There have also been instances in the Arkansas River basin, he said after the meeting.

On the same day that the Simpson v. Bijou ruling came, the state Legislature entered the Arkansas Valley well rules into law. In 2003, it also gave the state engineer’s office authority to approve five-year substitute water supply plans and to develop future rules.

Nearly 1,800 wells in the Arkansas Valley are covered by Rule 14 group augmentation plans under the 1996 rules, and those would stay in place even if new well rules are adopted.

The new rules could benefit a farmer who wants to use his own surface water rights to replace water pumped from wells, revegetation projects or even someone drilling a new well for a business, Witte said. At the same time, they would protect downstream water users and Colorado’s obligation under the Arkansas River Compact.

Witte acknowledged that there might an “augmentation gap” that makes finding sources of replacement water difficult, as discussed by the Arkansas Basin Roundtable recently. Permanently changing water uses still would require a trip to court.

But he said the purpose of the rules would be to give farmers a new tool to stay in business while complying with water law.

“We’re relying on data that were developed 30 years ago,” Witte said. “Life goes on and we need to think of ways to adjust and not be hampered by things already in place.”

More Arkansas River Basin coverage here.


Arkansas Basin Roundtable approves $175,000 for tailwater study

July 14, 2014
Flood irrigation in the Arkansas Valley via Greg Hobbs

Flood irrigation in the Arkansas Valley via Greg Hobbs

From The Pueblo Chieftain (Chris Woodka):

The state is being asked to help fund a study that looks at farmers’ contentions that estimates for return flows to the Arkansas River are inflated. A standard of 10 percent for tailwater — water that sheets off fields during irrigation before it can soak in — is used in mathematical models adopted during the 24-year Kansas v. Colorado U.S. Supreme Court case under the Arkansas River Compact. Those models also affect consumptive use rules that apply to surface water improvements such as sprinklers or drip irrigation.

The Arkansas Basin Roundtable last week forwarded a $175,000 grant request to the Colorado Water Conservation Board to determine if that number is too high.

“Farmers on the Fort Lyon did not believe 10 percent was really happening,” said Leah Martinsson, a lawyer working with the Lower Arkansas Valley Water Conservancy District, which is applying for the grant.

Straight line diagram of the Lower Arkansas Valley ditches via Headwaters

Straight line diagram of the Lower Arkansas Valley ditches via Headwaters

The ditch is more than 100 miles long and irrigates 94,000 acres and usually water short. That increases the likelihood that the estimate of tailwater runoff is too high, since much of the water never makes it back to the river, she explained. The higher the tailwater number, the greater the obligation from farmers to deliver water to the Arkansas River. So, reducing the figure in the group augmentation plans filed with the state would mean a reduction in the amount of replacement water.

While the concern of Fort Lyon farmers is the model used in the consumptive use rules, it also could affect the hydrologic-institution model that guides Colorado’s obligation from wells.

“If we are prepared with good technical data, we will go in and try to change the H-I model,” said Bill Tyner, assistant division engineer with the Division of Water Resources.

It would not be the first attempt to change the model. The state also is funding an ongoing lysimeter study at Rocky Ford to determine if evapotransporation rates in the Arkansas Valley are higher than assumed in the model.

Another study is looking at whether ponds that feed sprinklers leak more than the model assumes.

More Arkansas River Basin coverage here and here.


Lower Arkansas Valley Water Conservancy District board meeting recap

June 20, 2014
Orr Manufacturing Vertical Impact Sprinkler circa 1928 via the Irrigation Museum

Orr Manufacturing Vertical Impact Sprinkler circa 1928 via the Irrigation Museum

From The Pueblo Chieftain (Chris Woodka):

More than 28,000 acres of Arkansas Valley farm ground — roughly a tenth of all irrigated land — is being covered by group plans that guard against increased consumptive use from surface irrigation improvements.

The state pushed consumptive use rules for irrigation through Division 2 Water Court in 2010. The rules are meant to protect Colorado in its 1949 Arkansas River Compact with Kansas.

Rule 10 allows groups to file plans in order to save on legal, engineering and administrative costs.

The Lower Arkansas Valley Water Conservancy District is administering two Rule 10 plans this year.

One covers farms on the Fort Lyon, which represents 18,000 acres. About 12,000 of those acres are under sprinklers, while the remainder are flood irrigated.

The second plan covers 10,000 acres not on the Fort Lyon Canal, with two-thirds of that under sprinklers and 105 acres using drip irrigation.

“About two-thirds of the farm are in the Fort Lyon plan. The goal is eventually to have them in their own group plan that would be self-sustaining,” said the district’s engineer Jack Goble during a presentation at Wednesday’s board meeting.

This year’s Lower Ark plans cover 235 improvements on 92 farms that should require almost 1,900 acre-feet of replacement water. The amount owed is determined by a mathematical model devised by the Colorado Division of Water Resources that determines how much water would have been used before and after improvements.

“It’s a guess of what we’ll owe,” Goble said. “The model is almost like a parallel universe.”

The more water used in irrigation increases the amount owed to replace depletions in the river.

“The more water that comes through the ditch, the more is owed,” Goble said.

Goble walked the board through the complicated model, which takes irrigation flows, precipitation, seepage and runoff into account.

The Lower Ark district is in the second year of a study on pond leakage, which so far is showing that more water is escaping than accounted for in the state’s model. Data from the study in some cases has been applied to specific ponds.

More Ark Valley Consumptive Use Rules coverage here and here.


Arkansas River Basin: “We’re getting screwed here. Does Kansas owe me water?” — Dale Mauch

December 15, 2013
Augmentation pond photo via Irrigation Doctor, Inc.

Augmentation pond photo via Irrigation Doctor, Inc.

From The Pueblo Chieftain (Chris Woodka):

Farmers are still not happy with the state’s accounting of the impact of surface irrigation improvements on return flows to the Arkansas River.

“We’ve got to change the formula,” Lamar farmer Dale Mauch told officials Friday after learning of preliminary results from a two-year pond study at a meeting hosted by the Prowers County Soil Conservation District. “We’re getting screwed here. Does Kansas owe me water?”

The pond study is being conducted under a state grant through the Lower Arkansas Valley Water Conservancy District and won’t be finished until next year. But results from 2013 show that ponds leak about twice as much as assumed under a state formula adopted in 2010 surface irrigation rules.

The rules are meant to assure that Colorado does not take more of its share than it is entitled to under the Arkansas River Compact with Kansas, said Assistant Division Engineer Bill Tyner.

The Lower Ark district provided 1,160 acre-feet of replacement water to make up for calculated deficits caused by sprinklers on 107 farms under Rule 10 plans this year. Most of the sprinklers are located on the Fort Lyon Canal. Those included 81 ponds, which were presumed to leak at a rate of about 10 percent under the state formula.

But a study of 20 ponds by engineers Jerry Knudsen and Brian Lauritsen shows they leaked anywhere from 3-45 percent, averaging about 18 percent. Those numbers were used in the state calculations, but only for ponds that were measured.

Ponds with higher leakage tend to crack as they dry up between irrigation runs, Knudsen said. Because of the drought, irrigation runs were less frequent this year, and most of the 50 farmers who attended the meeting expressed doubts that a water-short ditch like the Fort Lyon Canal owed any water to the river under those conditions.

Cutting back the amount of augmentation water needed for the Rule 10 plans is critical to making irrigation affordable. The price of augmentation water is expected to increase, especially in years such as this one when it is not readily available. Water used for this year’s Rule 10 plans ranged in cost from Fry-Ark water, which costs $7.50 per acre-foot, to water leased from the Pueblo Board of Water Works, at a cost of $250 per acre-foot (including storage). Other sources included the Larkspur Ditch and Twin Lakes water owned by the Lower Ark district.

While the cost is going up, water leasing also competes with well groups, said Jay Winner, manager of the Lower Ark district.

“Buying water on the spot market in the future is not promising,” Winner said.

More Arkansas River Basin coverage here and here.


CWCB: Study for the Lower Ark shows that the average unlined farm pond leaks as much as 20%

July 31, 2013

farmponddryingup2011droughtoklahomanoaa.jpg

From The Pueblo Chieftain (Chris Woodka):

Most ponds used by farmers to feed sprinkler systems are losing more than 20 percent of the water stored in them because of leakage.

A preliminary written report was released this week detailing the findings of the study, being conducted by Agritech Consulting and Valley Ag Consulting for the Lower Arkansas Valley Water Conservancy District. The study is being conducted in hopes of altering a state formula that assumes only 3 percent loss. At a meeting earlier this month, the district reported that farmers in the study already are able to claim greater leakage, but officials held out little hope the assumptions of the state formula could be changed. The study found 13 of the 22 ponds in the study had leakage rates higher than 20 percent. Measurements were taken as water flowed into ponds and as it ran through sprinklers. Overall, seepage cost farmers 300 acre-feet of the 1,340 acre-feet that flowed into ponds. The state’s formula would have given them credit for just 40 acre-feet.

Gerald Knudsen of Agritech, who analyzed the results of the study, said drought may have been a factor in the data from the first year of the study. The study will continue next year that will help researchers evaluate the relationship between seepage and physical or environmental conditions. “This further review may be significant since the data collected to date represents drought conditions when there is a longer period of time between runs and more frequent use of the ponds may reduce the seepage rates,” the report stated.

The study is being funded by the Colorado Water Conservation Board.

The state uses pond leakage as one factor in its formula to evaluate consumptive use of surface irrigation improvements under 2010 rules designed to head off future disputes with Kansas. The Lower Ark district offers a group plan that helps farmers repay water the state says is owed to the river.

More coverage from Chris Woodka writing for The Pueblo Chieftain:

A study of leakage in ponds that feed field irrigation systems already is saving some farmers thousands of dollars in water cost.

But a state formula that assumes only 3 percent of the water leaks won’t be changed until the study results are final — and maybe not even then. The formula is used under Rule 10 of the state engineer’s 2010 consumptive use rules to prevent expansion of water rights under surface irrigation rules. The state pushed for the rules to avoid further challenges by Kansas of Arkansas River Compact violations.

Farmers have to pay for replacement water, so if they can show they are losing more than presumed, they spend less.

The Lower Arkansas Valley Water Conservancy District is funding the study by Gerry Knudsen of Agritech and Brian Lauritsen of Valley Ag Consulting to determine how much water leaks out of the ponds.

Seepage varies from 3-5 percent in some ponds to 44 percent at others, depending on how dry the ponds are when they first fill and the type of soil. A total of 26 ponds are in the study, located mostly on the Fort Lyon Canal, where most of the sprinklers are.

The ponds had 1,340 acre-feet of inflow, and lost 300 acre-feet, or 22 percent.

The results from individual ponds already are being used by the Colorado Division of Water Resources to calculate losses on specific farms, but have not altered the presumptive model.

The study, funded by a $60,000 grant from the Colorado Water Conservation Board that was obtained by the Lower Ark district, won’t be complete until 2014. Even then, it might not change the state’s outlook on pond leakage.

“My view is that the ponds will have to be measured forever,” said Jay Winner, manager of the Lower Ark district. “The ponds which have instrumentation will get the credit.”

Knudsen agreed, saying it’s similar to how GPS systems were incorporated into cultivation several years ago because the initial technology soon became essential rather than optional.

Lauritsen added that better meters are needed and must be properly calibrated to get the best results.

More Arkansas Valley consumptive use rules coverage here and here.


Rules designed to limit consumptive use now cover nearly 20,000 acres in the Arkansas Valley

December 10, 2011

irrigation.jpg

From The Pueblo Chieftain (Chris Woodka):

Understanding irrigation in the Lower Arkansas Valley

Consumptive use refers to the amount of water a crop uses to grow, either through uptake into the plant and transpiration, or through evaporation. Usually it is measured in inches, but presumptive factors have been incorporated into the hydrologic-institutional model under the U.S. Supreme Court Kansas v. Colorado case.

Return flow is excess water applied to fields that runs off as tailwater or infiltrates soil. Water also can seep out of earthen ditches as it makes its way to the fields.

Water-short ditches, such as the Fort Lyon Canal or Holbrook Ditch, typically have more ground available to irrigate than water supplies will cover. Other ditches, such as the Catlin or High Line canals, have plentiful water except in very dry years.

Sprinklers, drip irrigation and ditch lining allow water to be applied more efficiently to fields. In the process, more water could be consumed as more acreage is planted on water-short ditches or used more often on ditches with adequate water. Return flows could be reduced as a result.

State engineer rules were adopted in Division 2 water court in 2009 to prevent shortages of return flows on the Arkansas River, to downstream users in both Colorado and Kansas…

This year, the Lower Arkansas Valley Water Conservancy District established a group plan for farmers who use ponds to feed sprinklers to comply using formulas under Rule 10 of the surface irrigation rules. The plan also covers other types of improvements such as ditch lining and drip irrigation, but sprinklers account for nearly all of the impact so far. The Lower Ark district will use water from other sources, such as a five-year lease agreement with the Pueblo Board of Water Works, to provide augmentation water to make up depletions from increased consumptive use.

While the group plan requires a retainer fee and payment for augmentation water if the formula shows depletion, the payment is far less than farmers otherwise would spend on engineering at each site to show losses. So far, 88 farms with 104 improvements covering 19,767 acres are enrolled in the Lower Ark’s Rule 10 plan, said Heath Kuntz, the district’s engineering consultant. “We’re anticipating a lot of growth over the next few years,” Jay Winner, general manager of the Lower Ark district, told the compact administration.

From the state’s point of view, the program has been the backbone for enforcing the new rules. About 75 farms were signed up at the beginning of the program in April, and the others have signed on at the end of the irrigation season as the state assessed impacts, said Bill Tyner, assistant engineer for Water Division 2. “The Rule 10 plan has turned out to be the most successful part of the rules,” Tyner said, thanking the Lower Ark district and the Colorado Water Conservation Board for the seed money which launched the group plan.

More Ark Valley consumptive use rules coverage here and here.


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