The Conspicuous Absence of Climate Change in New Mexico’s State Water Planning

, senior climate scientist | August 10, 2016, 9:54 am EST
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For generations, water management has been a challenge for the state of New Mexico.

The state has had a comprehensive water planning process since 2003, utilizing the regional plans from 16 different water districts. This year, the State Water Plan is being revised, but the process has offered few indications that it will take climate change into account.

Since the plan shapes how resources will be allocated to water management for many years to come, there is a risk that the state might spend its precious financial and water resources unwisely.

“Water is the common denominator of New Mexico’s future and is indispensable to the quality of life of the state’s residents,” according to the 2013 New Mexico State Water Plan Review. Yet water resources across the West are changing with changes in the climate. Winter snowpacks tend to be smaller, while summers tend to feature more heat waves.

Satellite images comparing full and empty reservoir

In 2013, the Elephant Butte Reservoir reached its lowest level in 40 years (right)—just 3 percent of its storage capacity, compared with a nearly full reservoir in 1994 (left). As a result, farmers received less than 10 percent of their typical irrigation water, forcing them to turn to groundwater and other sources.

Rainfall, when it occurs, tends to happen in more extreme deluges, leading to flooding. And the timing of precipitation over the course of the year is shifting, creating mismatches between water supply and water demand, especially for agriculture.

Such trends have been well documented, and they’re projected to continue as the global climate becomes warmer. The record-breaking temperatures in New Mexico already reported this summer may eventually become the new normal.

One might expect a state like New Mexico, where water is such a precious resource, to pay close attention to climate projections and to plan carefully for its future water security. Unfortunately, this does not appear to be the case, at least not at the state level. This omission in the current water planning process puts the state at risk of squandering the state’s financial resources implementing a plan that is mismatched to the state’s water security needs.

Evidence of absence

Water planning in New Mexico takes place through the Interstate Stream Commission, which organizes planning activities and delivers guidance to the 16 water regions in the State. The ISC is currently accepting revised water plans from the regions, with the aim of pulling them together into a revised State Water Plan later this year. In 2013, the ISC completed a review—approved by the governor—of the 2003 State Water Plan, aimed at informing an update of the state and regional water plans.

Unfortunately, the 2013 review made no mention of climate change, despite the governor’s acknowledgement that year that “Unprecedented drought, wildfires, and floods have put further stress on New Mexico’s aging water infrastructure, in communities large and small across the state.”

These effects can all be linked to climate change, and are expected to worsen over time. The Southwest regional component of the 2014 National Climate Assessment made these points very clear, reinforcing the previous 2009 National Climate Assessment, and provided an opportunity for the ISC to make sure the planning process took these trends into account. However, the acceptance criteria approved by the ISC in December 2015 offered no such guidance to the regions and failed to mention the importance of climate change for water planning.

The main product of the 2013 review was the development of a common format and set of requirements for the regional water plans. In the Updated Regional Water Planning Handbook issued by the ISC, there is a section calling for climate information, in relation to water supply issues. The problem is that the Handbook only calls for a “general summary of the climate conditions in the region, including … any new studies or information that are indicative of changed climate conditions.”

Such a “general summary” is unlikely to be sufficiently detailed for water planning purposes, and the indications of “changed climate conditions” is inherently backward-looking, rather than forward-looking.

Here’s the text of the guidelines for this section, quoted in full:

This section will include a general summary of the climate conditions in the region, including average and ranges of precipitation, evaporation, general climate patterns, and any new studies or information that are indicative of changed climate conditions. Climate data will be reported in a consistent format as follows:

  •  Station name, number, location, elevation, period of record, average annual temperature, average annual precipitation, average summer and winter temperatures and precipitation, and minimum and maximum temperatures and precipitation.
  •  Precipitation and evaporation data will be based on National Oceanic and Atmospheric Administration (NOAA) monitoring station records and can be supplemented by other valid research if available.
  • Important data gaps (temporal or spatial) will be noted.

Recent studies that discuss trends in temperature, precipitation, or evapotranspiration within the region will be referenced.

While the station information and NOAA data are helpful, they are not sufficient to predict the future supply of water for individual regions. Furthermore, the inclusion of recent studies about climate trends does not appear to be mandatory, nor is there a process indicated for how to take these studies into account when projecting future water supply. Overall, there is an absence of guidance about how to access and utilize information that could be helpful to regions in projecting their further supplies of water.

Later, the Handbook describes how the state will calculate surface water supply, both for “average” and “drought” conditions:

  • Average annual historical amount of surface water diverted for beneficial use (average surface water supply) based on the NMOSE [New Mexico Office of the State Engineer] Water Use by Categories The diversion data are available statewide and will be the basis for a common technical approach for all regions. However, in areas where interstate stream compacts or court decrees specify the legal entitlement, these data will also be presented.
  • Annual drought surface water supply based on the NMOSE Water Use by Categories reports adjusted for drought indices that reflect the relationship between the most recent data from the OSE report and long-term records.

Note that these calculations only take into account historical amounts and past records. No projections of future water supply are included.

The draft regional plans each contain a section developed by the state, summarizing recent studies related to climate trends. The language is similar across the various regional plans, and it cites the evidence of climate change in the IPCC reports and the National Climate Assessment. These reports don’t provide the necessary level of detail to plan for the expected impacts for each region in New Mexico. As a result, the plans instead list general impacts from a 2006 report, along with a note highlighting the urgency of taking these effects into account:

[T]he effects of climate change that are likely to occur in New Mexico and the planning region include (NMOSE/NMISC, 2006):

  • Temperature is expected to continue to rise.
  • Higher temperatures will result in a longer and warmer growing season, resulting in increased water demand on irrigated lands and increased evapotranspiration from riparian areas, grasslands and forests, and thus less recharge to aquifers.
  • Reservoir and other open water evaporation are expected to increase. Soil evaporation will also increase.
  • Precipitation is expected to be more concentrated and intense, leading to increased projected frequency and severity of flooding.  

To minimize the impact of these changes, it is imperative that New Mexico plan for dealing with variable water supplies, including focusing on drought planning and being prepared to maximize storage from extreme precipitation events while minimizing their adverse impacts.

What should the process look like?

A few things would be needed at the regional and state level for New Mexico to adequately account for climate change in its State Water Plan update.

First, the ISC would need to make climate projections available—from state or national sources—at a level that can be used by the regions. These projections should include information about the changing likelihood of future climate conditions, based on downscaled climate models. Depending on resource constraints and in-state capacity, the governor may find it useful to request better decision support from federal government agencies working with Western governors to help state agencies incorporate these projections.

Second, the state government should support the regions with technical assistance in utilizing these projections as each region develops and implements its water plan. The regional steering committees may need such assistance to effectively interpret and incorporate projections into the water plans. Also, the ISC may need to take concrete steps to build capacity for increasing the understanding of technical details within the regional committees in order to make it easier to synthesize the State Water Plan.

Third, the ISC should develop additional guidance about how to incorporate climate projections into regional water plans. This guidance should be included in the next update of the Regional Water Planning Handbook in order to make the process more streamlined the next time around. In the meantime, the ISC could use the current round of planning to explore what approaches work best.

Fourth, the State Engineer who oversees the ISC should ensure that the State Water Plan is not merely a bundle of regional plans loosely stitched together, with proposed projects, programs, and  policies left to the regions to implement without any accountability.

Climate effects that occur in one region can have a cascading effect on other regions, and this means that a comprehensive state plan needs to explore such interactions. Because the ISC is already in charge of bringing together the 16 regional plans, it seems to be the right place for a comprehensive assessment to take place.

A comprehensive assessment would allow the state to deliver feedback to the regions, in the form of regional water budgets. But with thin resources and no specific mandate to do so, it appears unlikely that the ISC would undertake this difficult—but necessary—task.

What’s at stake?

If New Mexico’s current water planning process doesn’t robustly include expectations about the effects of climate change, the state and regional plans could plan for projects and infrastructure that fall short of future needs. The result could be that regions are left high and dry—inadequately prepared for the coming climate.

At the same time, the state may invest its financial resources in measures that are mismatched to its needs. Those resources won’t come back after they’re spent. Instead, the resources could be used in support of robust investments that anticipate future conditions and help the state become more prepared for what’s to come.

New Mexico is a resilient state, and New Mexicans have a long history of adapting to scarce water resources. The state can honor that legacy by building a resilient approach in its water planning, using relevant information about climate change. Fortunately, there is still time to do so before the state plan is complete—but the planning agencies must act quickly.

NASA

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