water

Comments on the alleged megadrought

During the past few weeks, media have been hyping alarm about a new study  that claims that the Southwestern US is entering a megadrought and that the drought is made more severe by human-caused global warming. That claim is based on tree-ring analysis and computer modeling speculation.

Droughts have occurred due to natural cycles, but there is no physical evidence that carbon dioxide emissions play a significant role is controlling global temperature or precipitation. The new paper presents no evidence that alleged “human-caused” global warming is making the drought worse, it is just speculation. In fact, many droughts are associated with cooler periods.

Let’s put things in perspective. Here are the data for the past 1,200 years. It seems that “megadroughts” have occurred naturally, without any human influence.

These data show that the 20th century was wetter than normal. However, the next graph shows that there have been droughts. But, rather that entering a megadrought, we seem to be emerging from a dryer period according to NOAA.

The graph above comes from a 4-minute video posted by Tony Heller, on his “Real Climate Science” blog. This video destroys claims that the western United States is currently experiencing a nearly unprecedented megadrought. Video: https://youtu.be/W9xCWDZmUT4

 

Related:

Evidence that CO2 emissions do not intensify the greenhouse effect

The Broken Greenhouse – Why CO2 is a minor player in global climate

A Review of the state of Climate Science

Drought in the West

Desalination of Sea Water Can Augment Our Water Supply Without Harming Sea Life

Since the Colorado River may not supply us with all the water we need, we should turn to the oceans.

Desalination of sea water can produce the freshwater we need to augment our natural supplies. The most common method is reverse osmosis where the sea water is forced through a semi-permeable membrane which removes the salt.

However, the process is energy intensive which some environmentalists claim will put more dread carbon dioxide into the atmosphere if the electricity comes from fossil-fuels. That can be solved by powering the plants with small, dedicated nuclear generators. (Powering such plants with wind or solar energy will make freshwater production intermittent and unpredictable.)

The other claim by some environmentalists is that the effluent from the desalinization process, very salty brine, is harmful to wildlife. A new study shows this concern is overblown.

A seven-year study, jointly conducted by Southern Cross University and the University of New South Wales at the Sydney (Australia) desalination plant found that when the plant was in operation, fish population in the area almost tripled. Fish populations decreased to normal when the plant was not operating. The Sydney plant has a capacity of producing 74,000 acre-feet of water per year.

Lead researcher Professor Brendan Kelaher said, “At the start of this project, we thought the hypersaline brine would negatively impact fish life. We were surprised and impressed at the clear positive effect on the abundance of fish, as well as the numbers of fish species. Importantly, the positive effects on fish life also included a 133 per cent increase in fish targeted by commercial and recreational fishers. As to why fish like it so much, we think they might be responding to turbulence created by dynamic mixing associated with the high-pressure release of the brine. However, more research is needed.” (Source) The report mentions no detrimental effects on fish or other sea life. The research was published in the journal Environmental Science & Technology. http://pubs.acs.org/doi/abs/10.1021/acs.est.9b03565

I did try to find information on negative impacts to marine life of concentrated brine being pumped into the ocean, but all I could find was speculation, no actual physical evidence. Apparently harm is minimal. As noted by marine biologist Daniel Cartamil of Scripps Institution of Oceanography, intake water may contain tiny organisms (plankton), including the eggs and larvae of marine life. None of these organisms survive their journey through the plant. However, this entrainment typically accounts for only about 1 percent or 2 percent of plankton mortality in a given area. Cartamil says this about the salty brine discharge: “In theory, marine life (particularly plankton) could be harmed by prolonged exposure to salinity levels higher than those they normally cope with. The most common solution to this problem is to mix the brine back into the seawater with high-speed jets, a process so efficient that salinity levels are effectively back to normal within 100 feet of the release point.” (Source)

Perhaps Arizona, California, and Mexico will take heart and build more modern desalination plants near the Sea of Cortez and the Pacific Ocean to help ease our dependence on the Colorado River. Some of the salt could be recovered for industrial applications. There is a desalination plant in Yuma, built in 1992 to treat agricultural runoff and conserve water in Lake Mead. But its technology is outdated. There is also a desalination plant just north of San Diego with a capacity of 56,000 acre-feet per year. Building more and bigger desalination plants powered by nuclear generators is technologically feasible but politically problematic.

Articles on small nuclear reactors:

A New Type of Molten Salt Nuclear Reactor

Small Modular Reactor by Westinghouse

What are small modular nuclear reactors, and why are three provinces uniting to build them?

Advanced Small Modular Reactors

Water and Irrigated Agriculture in Arizona

The Water Resources Research Center of the University of Arizona has just published “Arroyo 2018″ which is devoted to the title subject. You can download the 16-page report at:

https://wrrc.arizona.edu/sites/wrrc.arizona.edu/files/attachment/Arroyo-2018-revised.pdf

Here are some excerpts and highlights:

Archeological evidence suggests that irrigated agriculture first arrived along the Santa Cruz River in southern Arizona around 1200 BCE. During this time, irrigation canals were constructed along the river near the current Interstate-10 corridor just west of Tucson. These early farmers irrigated corn, tobacco, and squash.

Between 300 BCE and 1450 AD, native people constructed a network of canals near the Salt and Gila Rivers in South Central Arizona, where they developed a distinct culture known as “Hohokam”. Evidence of these canals exists today near the sites of the Pueblo Grande Village on the east side of Phoenix, and the Casa Grande village west of Florence. The disappearance of this civilization may have been due to changes and variability of the local climate.

Following the demise of the Hohokam, the Xalychidom Piipaash (Maricopa) and Onk Akimel O’odham (Pima) tribes became established in southern and central Arizona. These tribes continued using irrigated agriculture, but with simpler canal systems.

By the mid-19th century, when American and Europeans made the trip across the deserts of the Southwest to reach the California gold fields, the Gila River people diverted water from the river to agricultural fields in the valley of the Middle Gila, creating a virtual breadbasket in Arizona. They supplied large quantities of wheat to the U.S. military and traded farm products, such as beans and squashes, to travelers and newcomers.

By the late 1800s, American settlers had diverted much of the water of the Gila and Salt Rivers that supported native agriculture, causing the Pima and Maricopa tribes to lose their livelihood and ushering in an era of extreme hardship for the tribes.

According to the Arizona Department of Water Resources, agriculture accounts for 68 percent of water use in Arizona. A 2017 study by University of Arizona economists estimated that agriculture contributes $23.3 billion to the Arizona economy.

Arroyo 2018 discusses the milestones in water use and development:

The Reclamation Act of 1902 allowed the federal government to fund construction of dams and other irrigation projects.

The Central Arizona Project (CAP), initiated in 1968, diverts water from the Colorado River for use in agriculture and municipalities.

The Groundwater Management Act of 1980 regulated extraction of groundwater. Southern Arizona was divided into Active Management Areas where extraction of groundwater for agricultural use is limited. Agriculture has transitioned to more CAP water. By 2014, groundwater accounted for 40 percent of the state’s annual water use.

Arroyo 2018 notes that farmers have been able to reduce water use, while increasing yields, by making improvements to irrigation systems. Several of those improvements are discussed.

Also, the introduction of genetically modified crops that are resistant to herbicides has made possible the adoption of no-till farming in Arizona. With no-till agriculture, farmers can leave biomass from harvested crops on fields, which lowers soil temperature, reducing soil evaporation and soil salinity. It can also prevent soil erosion.

Arizona farmers are also exploring new crops which use less water: Agave can be marketable for tequila, fiber, and biofuel. Industrial hemp can provide fiber. Guayule can yield rubber and biofuel.

The report concludes:

The agricultural industry has a significant impact on Arizona’s economy, and it is a dominant force in many rural communities across the state. Because different regions have different water conditions, farmers must consider location-specific factors in their water management decisions. Along the Colorado River and Lower Gila River, growers hold some of the oldest and most secure water rights in the state. With this water they have developed a nationally important region for vegetable production. In Central Arizona, CAP water has alleviated groundwater overdraft problems, but the potential for shortage in CAP’s supply is increasing uncertainty in this region. Here, farmers and irrigation districts face the real possibility of being forced to go back to the groundwater pumps or to take lands out of production. Beyond the reach of the CAP, agriculture reliant on groundwater is watching water levels fall as communities struggle to find acceptable regulatory solutions to the threat of depletion.

Growing demands for water, food, and fiber, coupled with near-term likelihood of Colorado River shortage, have led to increased focus on Arizona’s agricultural water use. Water efficiency gains have been substantial in recent decades, reducing total water use while increasing agricultural production statewide. There is still room for efficiency improvements, with the help of science and technology and financial assistance. As they continue to grow, cities and other water users will continue to look for ways to supplement their water supplies through voluntary water transactions with farmers that include attention to impacts on rural communities. Although sometimes contentious, this process can yield mutual benefits. The need for food and fiber will grow locally and globally; and because it is more reliable and productive than dryland farming, irrigated agriculture will supply this need. Finding the right balance among competing water demands in Arizona will take continued collaborations among growers, government, the scientific community, and concerned citizens.

Related articles:

Tucson transitioning to a renewable water supply

Guayule, a desert rubber plant

USGS claims that mercury and selenium are accumulating in the Colorado River

A study conducted by the U.S. Geological Survey (USGS) claims to have found “relatively high -compared with other large rivers” concentrations of mercury (Hg) and selenium (Se) in the food web along the Colorado River between Glen Canyon Dam and the Grand Canyon, The study was done in the summer of 2008, but curiously, results were just published in the journal Environmental Toxicology and Chemistry in August 2015. Perhaps they were taking advantage of publicity associated with the toxic spill from the Gold King mine in Colorado earlier this month.

USGS Hg Se study map

Some excerpts from the press release:

“The study, led by the U.S. Geological Survey, found that concentrations of mercury and selenium in Colorado River food webs of the Grand Canyon National Park, regularly exceeded risk thresholds for fish and wildlife. These risk thresholds indicate the concentrations of toxins in food that could be harmful if eaten by fish, wildlife and humans. These findings add to a growing body of research demonstrating that remote ecosystems are vulnerable to long-range transport and bioaccumulation of contaminants.”

“The study examined food webs at six sites along nearly 250 miles of the Colorado River downstream from Glen Canyon Dam within Glen Canyon National Recreation Area and Grand Canyon National Park in the summer of 2008. The researchers found that mercury and selenium concentrations in minnows and invertebrates exceeded dietary fish and wildlife toxicity thresholds.”

“Although the number of samples was relatively low, mercury levels in rainbow trout, the most common species harvested by anglers in the study area, were below the EPA threshold that would trigger advisories for human consumption.”

See full paper: http://onlinelibrary.wiley.com/doi/10.1002/etc.3077/epdf

From the paper:

“Sampling occurred from 12 to 28 June 2008. At each site, we collected representative basal resources (organic matter and primary producers), macroinvertebrates, and fishes. Basal resources included fine benthic organic matter, seston (suspended organic matter), epilithon (benthic biofilm), attached algae (Cladophora sp.), and epiphyton (diatoms attached to Cladophora). We collected fine benthic organic matter from sandy depositional habitats using a Ponar dredge (0.052 m2 ) deployed from a boat.”

As far as I can determine, the study analyzed fewer than 25 samples of each group along 250 miles of river. That is indeed a very low number upon which to form conclusions.

“In the present study we found no significant differences in Hg and Se accumulation among sites throughout the Grand Canyon.”

“There is a well-documented antagonistic interaction between Se and Hg, whereby Se protects animals from Hg toxicity when Hg:Se molar ratios are approximately 1 or less. The Hg:Se molar ratios were typically much lower than 1 in the present study, ranging from 0.04 (rainbow trout) to 0.38 (fathead minnow) among fish species. Assuming that Se and Hg in prey are equally transferred to consumers, this large excess of Se in this system suggests that the risks of Hg toxicity could be considerably lower than the Hg wildlife risk values alone would indicate.”

From the press release:

“The good news is that concentrations of mercury in rainbow trout were very low in the popular Glen Canyon sport fishery, and all of the large rainbow trout analyzed from the Grand Canyon were also well below the risk thresholds for humans,” said one of the study authors.

“We also found some surprising patterns of mercury in rainbow trout in the Grand Canyon. Biomagnification usually leads to large fish having higher concentrations of mercury than small fish. But we found the opposite pattern, where small, 3-inch rainbow trout in the Grand Canyon had higher concentrations than the larger rainbow trout that anglers target.”

Regarding mercury: “Airborne transport and deposition — with much of it coming from outside the country — is most commonly identified as the mechanism for contaminant introduction to remote ecosystems, and this is a potential pathway for mercury entering the Grand Canyon food web.” Selenium is derived from “irrigation of selenium-rich soils in the upper Colorado River basin contributes much of the selenium that is present in the Colorado River in Grand Canyon.”

The paper abstract notes that “consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking.” That would seem to cast in doubt the proposed source of selenium from upstream irrigation of agricultural land. The “relatively high” concentrations they were talking about in fish are 0.17–1.59 ppm Hg and 1.35–2.65 ppm Se.

END

How Tucson Water spends Conservation Fund money and a suggestion for a better way

If you are a Tucson Water customer, you may have noticed an item on the back page of your water bill listed as: “CONSRV FEE $.07/CCF.” This means you are contributing seven cents per cubic foot of water used to a conservation fund. That may not sound like much, but according to an article by Tim Steller, that added up to $2.95 million last year. By the way, this “contribution” to the conservation fund will rise to eight cents per CCF on July 15.

So, how is that money being used? The answer to that question is the objective of a Freedom of Information (FOIA) request filed last January by Mark Lewis, one of five members of the City’s Conservation and Education Subcommittee of the Citizens Water Advisory Committee.

Tucson Water has to date refused to provide the information requested by Mr. Lewis. According to Mr. Lewis, the information requested is “to gather the documentation and information necessary to ensure the funds collected from Tucson Water customers under the Conservation Fee program has been properly accounted for, audited, and expensed.” Mr. Lewis has expressed concern, in his role as an appointed advocate for the Rate Payers of Tucson Water, that the millions of dollars which have been spent through this fund have not been properly tracked or audited and that more recent uses of this fund are not consistent with the purpose of the fund: conserving water.

One conservation program promoted by Tucson Water is the replacement of old toilets with new low-flow models. Tucson Water will give you a $75 rebate toward the cost. According to Steller’s article, “water-wasting toilets remain in around 150,000 Tucson homes, and the program to replace them saved almost 11 million gallons in the first eight months of this fiscal year alone.” Mr. Lewis supports this program, but points out that the small rebate may be insufficient, especially for older homes which may have complicated plumbing issues that would make replacement more expensive.

Another conservation program is rainwater harvesting. Tucson Water will provide a rebate of up to $2000 for installing a system. Steller points out that “those rebates have mostly benefitted wealthier residents and so far have resulted in no measurable reduction in water use.” Mr. Lewis notes that the $900,000 in rain water rebates to date saved no water, but had the same money been spent on wasteful toilets it would have saved 173 million gallons of water to date.

You can read about the program in a brochure provided by Tucson Water: http://www.tucsonaz.gov/files/water/docs/Rainwater_Harvesting_Rebate_brochure.pdf

In that brochure, Tucson Water claims that “45% of the water we use goes to outdoor irrigation.” That number surprises me; I wonder if it is true. The brochure also notes that in order to qualify for the rebate, you have to take a free class. And here is where it gets interesting.

The qualifying class is run by Watershed Management Group, a consulting firm that, for a fee, will design a rainwater harvesting system for you. Three board members of Watershed Management Group, Catlow Shipek, Mark Murphy, and Amy McCoy, comprise three of the five members of the City’s Conservation and Education Subcommittee of the Citizens Water Advisory Committee. The classes are also given by a company that sells rain gutters according to Mr. Lewis. This situation has the appearance of crony capitalism and conflict of interest.

There is another scheme afoot. Tucson City Councilwoman Regina Romero has proposed that $300,000 be used to provide interest free loans to low-income residents so they can plant trees and have them watered by rainwater harvesting systems. Romero is concerned about the “unequal distribution of tree canopy in Tucson…” and its effect on the Urban Heat Island Effect (cities are warmer than surrounding countryside because all the asphalt and concrete absorb heat which makes nighttime cooling much slower). I see two potential problems with this scheme. First, we would have to cover a large part of the city with trees to have any significant effect. Second, all those trees will transpire water, losing moisture to the atmosphere rather than conserving water for reuse.

Given the information above, do you think your forced subsidy is being well-spent?

I have a suggestion on how the money could be spent to actually conserve water.

One of the eco-fads promoted by Tucson Water is rainwater harvesting at residences. So far, that program has resulted in no measurable reduction in water use. But perhaps, if that idea was used on a larger scale, it could help recharge our aquifers. Why don’t we collect storm-water runoff from city streets and in ephemeral flows in the Santa Cruz River and pump that water back into the aquifers via dry wells?

That idea is discussed by Chuck Graf, Senior Hydrologist, Arizona Department of

Environmental Quality in a short article in the Spring Issue of Arizona Water Resource Newsletter (link to article).

This idea is not new. Phoenix began recharging storm-water in the 1930s and now has more than 50,000 wells in operation. Many other communities also use this recharge method. Why not in Tucson and Pima County?

The practice of dry well recharge in Phoenix went largely unregulated until 1987 when legislature directed the Arizona Department of Environmental Quality (ADEQ) to license dry well installers and establish a registration program for existing and newly constructed dry wells. The law expressly limited the use of dry wells to the disposal of storm water. This limitation was intended to prevent disposal of hazardous chemicals into dry wells, which in the past had caused severe groundwater contamination plumes (some of which are still under remediation).

Graf explains the dry well method as follows:

“The dry well borehole is drilled in alluvial sediments, through any intervening fine-grained and cemented zones, into a permeable layer of clay-free sand, gravel, and cobbles. The permeable layer serves as the injection zone for the storm water. ADEQ requires at least 10 feet of separation between the bottom of the injection zone and the water table. Because groundwater commonly occurs at great depth in Arizona’s alluvial basins, installers often have considerable leeway to find an exceptionally permeable zone above the water table that maximizes dry well performance while maintaining a much greater separation distance than the 10-foot minimum.”

Graf goes on to write:

“Potential adverse groundwater quality impact is the biggest concern about dry wells. Although the definitive water quality study probably remains to be done, a number of studies, including a 10-year study in Los Angeles conducted by the Bureau of Reclamation and others, found little evidence for groundwater contamination. A 1985 study in Phoenix found that dry wells had a beneficial effect on groundwater quality with respect to major chemical constituents”

This idea should be considered. Perhaps then, our involuntary contribution to the “Conservation Fund” would actually conserve some water.

END

Free the Land from the Feds

The federal government owns more than 623 million acres of land, mostly in the western states. The recent defense spending bill included designation of new National Parks, Wild and Scenic Rivers, and National Heritage areas. How much land is enough?

Most federal land is administered by four agencies: the Bureau of Land management, 258.2 million acres; the Forest Service, 193 million acres; the Fish & Wildlife Service, 93 million acres; and the National Park Service, 79 million acres. Other federal land ownership includes military bases and land held in trust for Indian reservations. The map below shows the concentration of federal lands in the west.

Western federa lands

The State of Utah wants 31.2 million acres of its land back. “In an unprecedented challenge to federal dominance of Western state lands, Utah Gov. Gary Herbert in 2012 signed the ‘Transfer of Public Lands Act,’ which demands that Washington relinquish its hold on the land, which represents more than half of the state’s 54.3 million acres, by Dec. 31, 2014.” (Washington Times) We are still awaiting the outcome of this probably quixotic endeavor. But it sets a precedent and more western states should take up the quest.

Besides outright ownership, the feds are wreaking havoc on private property rights through the Endangered Species Act and the Clean Water Act.

In Arizona, for example, the right of Phoenix, the Salt River Project, and the Central Arizona Water Conservation District to divert Colorado River and Salt River water to Phoenix and Tucson is being threatened by the US Fish and Wildlife Service because those diversions allegedly endanger everything from gila topminnows, and chiricahua leopard frogs, as well as willow flycatchers.

The Town of Tombstone was forbidden to fix part of its water supply after it was destroyed in a forest fire because the source is in a wilderness area. (See Tombstone versus the United States)

The EPA and Corps of Engineers are attempting to expand the definitions in the Clean Water Act to include the most tenuous connection to “navigable waters” that would encompass private irrigation ditches, ponds, and puddles in order to gain more control over private property.

Perhaps the new Congress can address some of these abuses of federal regulations and free the land from Big Brother and allow states and private property owners to put the land to productive use.

See also:

Repeal the Endangered Species Act

Endangered Species paperwork to cost $206,098,920

Endangered species act could halt American energy boom

How NEPA crushes productivity

Forest thinning may increase runoff and supplement our water supply

Thinning of southwestern forests, partly to curb devastating forest fires, has long been a controversial subject. In general, forest thinning has been opposed by environmental groups.

Now, however, a new study (“Effects of Climate Variability and Accelerated Forest Thinning on Watershed-Scale Runoff in Southwestern USA Ponderosa Pine Forests” published October 22, 2014) conducted by The Nature Conservancy and Northern Arizona University recommends accelerated forest thinning by mechanical means and controlled burns in central and northern Arizona forests. The study estimates that such thinning will increase runoff by about 20 percent, add to our water supply, and make forests more resilient. You can read the entire study here.

Forest thinning study area

The study abstract reads:

The recent mortality of up to 20% of forests and woodlands in the southwestern United States, along with declining stream flows and projected future water shortages, heightens the need to understand how management practices can enhance forest resilience and functioning under unprecedented scales of drought and wildfire. To address this challenge, a combination of mechanical thinning and fire treatments are planned for 238,000 hectares (588,000 acres) of ponderosa pine (Pinus ponderosa) forests across central Arizona, USA. Mechanical thinning can increase runoff at fine scales, as well as reduce fire risk and tree water stress during drought, but the effects of this practice have not been studied at scales commensurate with recent forest disturbances or under a highly variable climate. Modifying a historical runoff model, we constructed scenarios to estimate increases in runoff from thinning ponderosa pine at the landscape and watershed scales based on driving variables: pace, extent and intensity of forest treatments and variability in winter precipitation. We found that runoff on thinned forests was about 20% greater than unthinned forests, regardless of whether treatments occurred in a drought or pluvial period. The magnitude of this increase is similar to observed declines in snowpack for the region, suggesting that accelerated thinning may lessen runoff losses due to warming effects. Gains in runoff were temporary (six years after treatment) and modest when compared to mean annual runoff from the study watersheds (0–3%). Nonetheless gains observed during drought periods could play a role in augmenting river flows on a seasonal basis, improving conditions for water-dependent natural resources, as well as benefit water supplies for downstream communities. Results of this study and others suggest that accelerated forest thinning at large scales could improve the water balance and resilience of forests and sustain the ecosystem services they provide.

The study also notes that in “ponderosa pine forests of central Arizona, stand densities range from 2 to 44 times greater than during pre-settlement conditions” and all that extra foliage sucks up water and loses it through evapotranspiration, thereby decreasing the availability of water for downstream users and wildlife.

Congress has authorized a program called the Four Forest Restoration Initiative (4FRI) that will accelerate the use of mechanical thinning and prescribed burns across four national forests, treating 238,000 ha (588,000 acres) in the first analysis area over the next 10 years. That program should be expanded.

Tucson transitioning to a renewable water supply

The state of Tucson’s water supply is always a concern. So how are we doing? Recently, Docents at the Arizona Sonora Desert Museum had an update by Wally Wilson, chief hydrologist at Tucson Water. The reason is that we Docents often have to explain to museum visitors what all those rectangular ponds are doing in Avra Valley just west of the museum. The following material is taken from his talk.

Tucson gets water from four sources: pumped groundwater, water transported from the Colorado River via the Central Arizona Project canal (CAP), water reclaimed from sewers, and water treated from former industrial usage (Tucson Airport Reclamation Project, TARP). Water is measured in Acre-feet (AF). One AF is 325,851 gallons and one acre-foot will serve four residences in Tucson for a year. Mr. Wilson presented the following graph on water usage (as of 2011):

Transition-to-renewable-supplies

Notice that total water usage has been declining and has reached the level it was in 1994.  That was surprising to me. Perhaps our conservation efforts are paying off. Mr. Wilson noted that average residential use in Tucson is about 90 gallons per day per capita (versus 200 in Scottsdale). Tucson is conserving groundwater by using more and more CAP water. This graph shows that our groundwater use has declined to what it was in 1959 in spite of our increasing population.

In 2011, CAP supplied 64% of our water while groundwater supplied 20%. The remainder was made up of reclaimed water. Total production in 2011 was 120,350 AF. In 2013, Mr. Wilson expects CAP will supply 80% of our needs allowing us to decrease primary groundwater pumping.

Below is a map of the CAP system. It consists of ponds to recharge the aquifer, wells to pump the water, a treatment plant, and a reservoir which stores 60 million gallons.

Clearwater-map

There are three recharge areas which Tucson Water fondly calls CAVSARP, SAVSARP, and PMRRP. These are the areas featuring recharge ponds filled with CAP water and wells to reclaim the water after it recharges the aquifer.

Why put the water in ponds to sink into the aquifer rather than treating it and pumping it directly to consumers? There are several reasons. When we first began to receive CAP water it was treated and sent to households, but the water wreaked havoc with some of our old plumbing. The current system is plan B and it has several advantages besides being kinder to plumbing.

Water from the ponds sinks into the ground at the rate of about 1.5 feet per day. As it travels 300- to 400 feet to the water table, soil filters out any viruses and bacteria that may be in the water. This filtering method is much less expensive than disinfecting the water in a treatment plant. The water still goes through the Hayden-Udall treatment plant for filtering and chlorination.

Some numbers: CAVSARP recharges 70,000 to 80,000 AF/year and recovers 70,000 AF/year. SAVSARP is permitted to recharge 60,000 AF/year and recovers about 15,000 AF/year. We are still ramping up to use our total CAP allocation. PMRRP is permitted to recharge at the rate of 30,000 AF/year and recovers water at 14,000 AF/year.

Tucson Water claims that it loses about less than 2% of the water due to evaporation from the recharge ponds. The overall CAP system loses about 5% of its water due to evaporation. Most of that occurs in Lake Pleasant which acts as a storage buffer between supply and demand.

Mr. Wilson says Tucson will have plenty of water through 2050 and beyond because we are banking water in the recharge system (and we still have the groundwater). Tucson Water is also pursuing additional sources of renewable water such as water owned by Indian Tribes. For more information see http://cms3.tucsonaz.gov/water .

See also my older posts on our water supply:

Water Supply and Demand in Tucson

How much water is there?

Trends in groundwater levels around Tucson

EPA war on coal threatens Tucson water supply

Arizona may have larger potable groundwater resource

Southern Arizona gets about 43% of its water by pumping groundwater aquifers.  The geology is well-suit for this because Southern Arizona is in the Basin and Range province which contains very deep, fault-bounded valleys.  In some places, bedrock is as much as 15,000 feet below the surface.   Portions of the Tucson and Avra valleys are over 8,000 feet down to bedrock.  Such valleys are filled with alluvium and water.

Figure-1-salinity-statewide-map-v3

Currently, water for drinking exploits aquifers down to a depth of about 1,200 feet.  Generally water below that depth is too salty for drinking.

Following up on two previous studies, Estimated Depth to Bedrock in Arizona and Preliminary evaluation of Cenozoic Basins in Arizona for CO2 sequestration Potential, the Arizona Geological Survey in a new study, examined the salinities of Arizona groundwater.  The study is A Summary of Salinities in Arizona’s Deep Groundwater, Arizona Geological Survey Open-File Report, OFR-12-26.

As part of that study, geologists of the Arizona Geological Survey (AZGS) reviewed geophysical well logs to catalog the concentration of total dissolved solids (TDS, i.e., salinity) of 270 water wells.  This included all water wells that penetrated deeper than about 2,600 feet, which is the minimum depth necessary to sequester carbon dioxide.

Among the results of that study, AZGS found that on the Colorado Plateau and in the Basin and Range province, there are some areas where “Fresh water can extend as deep as 5,000 feet (1,500 m), but below 6,600 feet (2,000 m) only brackish or saline groundwater was encountered..”   Water is considered “fresh” if it contains less than 1,000 ppm (parts per million) TDS.  Water is “brackish” if TDS are 1,000- to 30,000 ppm.  “Saline” water contains greater than 30,000 ppm TDS.  Sea water is about 35,000 ppm TDS.

This means that we may be able to extract drinking water from deeper aquifers in some areas.

See also:

Water Supply and Demand in Tucson

How much water is there?

Trends in groundwater levels around Tucson

Tombstone versus the United States

TombstoneAllenStTombstone, Arizona, “the town too tough to die” just might be killed off by the US Forest Service. Tombstone gets most of it water supply from springs in the Miller Canyon Wilderness Area in the Huachuca Mountains about 25 miles west of the town. This water supply dates from 1881 when it was first developed by the Huachuca Water Company. Tombstone bought the pipeline and water rights in 1946.

In the early summer of 2011 the massive Monument wildfire denuded the eastern part of the Huachuca mountains. With vegetation destroyed, subsequent heavy monsoon rains caused flooding, mud slides, and debris flows that buried springs and crushed waterlines, thereby shutting off the main water supply to Tombstone.

Since that time, the City of Tombstone has tried to repair the damage, but has been stymied by a very obstinate Forest Service who will not allow heavy equipment into the wilderness area, even though the water rights pre-date establishment of the Wilderness Act.

According to the Goldwater Institute, who are suing the US Forest Service on behalf of the City of Tombstone, “Tombstone’s pipeline is under 12 feet of mud, rocks and other debris; while in other places, it is hanging in mid-air due to the ground being washed out from under it. In response, federal bureaucrats are refusing to allow Tombstone to unearth its springs and restore its waterlines unless they jump through a lengthy permitting process that will require the city to use horses and hand tools to remove boulders the size of Volkswagens.”

This is a case where bureaucratic regulations make no common sense and put citizens in danger even in spite of the fact that the City of Tombstone and the governor of Arizona declaring a state of emergency. The Goldwater Institute says, “The 10th Amendment protects states and their subdivisions from federal regulations that impede their ability to fulfill essential health and safety functions. Just as the federal government cannot regulate the States, it cannot regulate political subdivisions of the States, like the City of Tombstone. And despite what power it may claim, the Forest Service certainly has no power to regulate Tombstone to death.”

As water law expert Hugh Holub once wrote: “Though the water may originate on National Forest lands, Bureau of Land Management lands, and other federally managed lands, the rights to that water belongs to the farms and ranches and cities.” It seems that the Forest Service is ignoring that right.

The Forest Service has been portrayed as the villain here and perhaps they are. But maybe, they too are trapped by an inflexible process intrinsic to environmental laws such as the Wilderness Act and the Endangered Species Act, a process that makes timely, common sense responses to emergencies very difficult if not impossible.

See also:

Red Tape Rising – Federal Regulations Choke Economy

Repeal the Endangered Species Act

Red Squirrels and Green Dollars

Do we need the US Forest Service?