2018 #COleg: Mussel Free Colorado Act, sponsored by the water resources review committee, to be introduced in January

Quaggas on sandal at Lake Mead

From The Loveland Reporter-Herald (Pamela Johnson):

The Mussel Free Colorado Act, sponsored by the water resources review committee, is expected to be introduced to legislators in early 2018 and, if passed, would provide funding starting in 2019 by requiring boaters to buy an aquatic nuisance species stamp. These fees, $25 for Colorado residents and $50 for out-of-state boaters, would generate about $2.4 million per year and could increase with inflation, according to Colorado Parks and Wildlife.

The legislation also would increase the penalties for boaters who launch on lakes and reservoirs without an inspection from $50 to $100 and continues existing severance tax appropriations for the program.

The state’s Aquatic Nuisance Species Act, approved in 2008, required boat inspections starting in 2009 at many lakes and reservoirs across the state — a program that has resulted in more than 3.5 million boat inspections, that wildlife officials say truly has protected waters and that is a model to other states.

In fact, those inspections kept 25 mussel-infested boats off Colorado waters in 2017, keeping at bay a threat that state officials believe will likely increase as infestations spread nationwide through boats that move from water to water.

IRI: December Climate Briefing — New Year, Same La Niña #ENSO

From the International Research Institute for Climate and Society:

What’s New
Since last month’s briefing, sea-surface temperature (SST) anomalies in the area of the central equatorial Pacific Ocean that helps define El Niño and La Niña events, called the Nino3.4 region (see map below), have held at a similar average as the month before, around -0.8ºC. This number falls in the category of a weak La Niña state, although conditions will have to persist for several months for a La Niña to be officially documented in the historical record.

Because IRI and the National Oceanic and Atmospheric Administration’s Climate Prediction Center predict that these conditions will continue in the near-term, the ENSO alert level was upgraded last month from a La Niña Watch to a La Niña Advisory, where it remains.

The sea-surface temperatures in the Nino3.4 region (approximated here) serve as a primary metric of El Niño and La Niña conditions. Data from the IRI Data Library. Image: IRI/Elisabeth Gawthrop

ENSO Forecasts

To predict ENSO conditions, computers model the SSTs in the Nino3.4 region over the next several months. The plume graph below shows the outputs of these models, some of which use equations based on our physical understanding of the system (called dynamical models), and some of which use statistics, based on the long record of historical observations.

The average of the SST anomalies predicted by the models in this month’s forecast are very close to the predictions in last month’s forecast. Both dynamical and statistical models indicate a gradual warming over the forecast period, with both crossing into neutral ENSO territory in the March-May season. The dynamical models warm at higher rate, with conditions by next summer approaching +0.5ºC anomalies. The statistical models top out right around the 0.0ºC anomaly mark. This period at the end of the forecast, however, is past the spring predictability barrier and is highly uncertain.

This graph shows forecasts made by dynamical and statistical models for SST in the Nino 3.4 region for nine overlapping 3-month periods. Note that the expected skills of the models, based on historical performance, are not equal to one another.
The IRI/CPC probabilistic ENSO forecast issued mid-December 2017. Note that bars indicate likelihood of El Niño occurring, not its potential strength. Unlike the official ENSO forecast issued at the beginning of each month, IRI and CPC issue this updated forecast based solely on model outputs. The official forecast, available at http://1.usa.gov/1j9gA8b, also incorporates human judgement.

Based on the model outputs, La Niña conditions are the most likely ENSO outcome through early 2018, with the highest odds topping 80% for the December-February season that’s already underway. This month’s forecast has La Niña conditions persisting a little longer than last month’s forecast predicted, with neutral conditions not taking over as the most likely outcome until the March-May 2018 season.

The official probabilistic forecast issued by CPC and IRI in early December indicates a similar overall outlook but with somewhat higher La Niña odds for the next few seasons, and equal odds of La Niña and neutral conditions for the March-May season. This early-December forecast uses human judgement in addition to model output, while the mid-month forecast relies solely on model output. More on the difference between these forecasts in this IRI Medium post.

IRI’s Global Seasonal Forecasts

Each month, IRI issues seasonal climate forecasts for the entire globe. These forecasts take into account the latest model outputs and indicate which areas are more likely to see above- or below-normal temperatures and precipitation.

For the upcoming January – March 2018 season, odds are moderately to strongly tipped in favor of above-normal rainfall in the Philippines and parts of Indonesia, as well as central-northern South America. Areas of northern Europe and Asia show some increased odds for above-normal precipitation, as well as parts of the interior U.S. and Alaska. The southern United States and central to northern Mexico show the strongest, most widespread probabilities for drier-than-normal conditions. Parts of South America, southern Africa, central and eastern Asia, as well as smaller, scattered areas around the world show some increased chance for drier-than-normal conditions.

#Drought news: No change in depiction for #Colorado

Click here to go to the US Drought Monitor website. Here’s an excerpt:


[A] series of storm systems tracked across the lower 48 States, dropping light to moderate precipitation on the Northwest and northern half of the Rockies, which eventually entrained ample Gulf moisture into the system while over the lower Mississippi Valley. As a result, widespread moderate to heavy rains (2-6 inches, locally to 10 inches) fell from northeastern Texas northeastward into the southern and central Appalachians, with the greatest totals reported in central Arkansas and western Tennessee. As the systems trekked farther eastward, light to moderate precipitation also fell on the Northeast and the Carolinas as frigid conditions gradually replaced the mild air from earlier in the week across the eastern two-thirds of the Nation. Dry conditions prevailed across the Southwest, southern third of the High Plains, along the Gulf Coast, and in parts of the mid-Atlantic. In Hawaii, very heavy rains (4-10 inches) during December 20-21 in the central islands (western Maui, Lihue, eastern Molokai) interrupted what had been a relatively quiet (dry) December…

High Plains

Like the upper Midwest, with frigid temperatures, a non-growing season, frozen soils, and a climatological dry time of year (fall and winter), conditions should remained locked in place. With that said, light snow fell across portions of the High Plains, providing a thin to medium blanket of snow across Montana, North Dakota, Wyoming, Nebraska, northern halves of Colorado and Kansas, and southern South Dakota. Snow was lacking across northern South Dakota as readings dropped below 0 degF by week’s end. In more southern locations where temperatures were somewhat warmer and soils not as deeply frozen, short-term D1 and D2 was expanded in southwestern and central Kansas in response to similar drought indices in neighboring Oklahoma. Fortunately, with longer-term conditions not as dire in Kansas as in Oklahoma, impacts were less severe in Kansas…


Significant precipitation (1-4 inches) was limited to along the Washington and Oregon Coasts, in the northern Cascades, and the northern and central Rockies. Little or no precipitation was observed across much of the Southwest, Great Basin, and southern Rockies. While the Water Year-to-Date (WYTD) basin average precipitation was near to above-normal (85-120%) across the northern half of the West, warmer temperatures have reduced the average basin snow water content (SWC) to near or slightly below normal across the Northwest (50-100%), although eastern Idaho, Montana, and Wyoming has fared better (100-150%). With the recent precipitation, some slight reduction (improvement) in the western edges of the D0 and D1 areas in northwestern Montana were made as 1.5-4 inches brought indices at or closer to normal. The rest of Montana remained unchanged as light snow and subnormal temperatures locked conditions in place for now.

Across the southern half of the West, the WYTD precipitation and SWC have been the opposite of the north, with nearly all basins below normal (drier as one heads southward) and SWC at half of normal or less. Basin average precipitation and SWC in Arizona, southern Utah and Colorado, and New Mexico lingered below 25%, with SWC in single digits in parts of Arizona and New Mexico. In western New Mexico, dry weather during the past 90-days brought indices in line with D1 conditions. In central and eastern New Mexico, however, wet weather during late September has kept this area out of D1, but as this time period falls out of the past 90-days, D1 expansion is possible as very little precipitation has fallen since then. For example, Albuquerque, NM, has recorded 81 consecutive days without measurable precipitation through Dec. 25 (but 2.10 inches during Sep. 27-30). Across the rest of the Four Corners states, future degradation is possible due to a poor WYTD, but recent light precipitation, lower temperatures, and waiting for final December numbers and impacts staved off downgrades this week. In southern California, the Thomas Fire continued to burn, with 272,600 acres consumed as of Dec. 22.

#COleg: HB16-1256 South Platte Storage Study recommends surface and aquifer storage

Illustration shows water availability, in blue circles, compared with demand at various places along the South Platte River. The yellow area is the study area. (Illustration by Stantec).

Click here to read the report.

From The Sterling Journal-Advocate (Jeff Rice):

The best way to meet Colorado’s growing water demand and still protect irrigation water rights is probably a combination of increased surface storage and underground, or aquifer storage. But even that combination won’t bridge the gap between water demand and supply.

That’s the good news and the bad news from the recently-completed South Platte Storage Study Final Report, released Dec. 15. The report was written by Stantec, a Canada-based design, engineering and construction firm, and Leonard Rice Engineering of Denver.

The study, authorized by the Colorado General Assembly in House Bill 16-1256, looked at the stretch of the South Platte River between Kersey and the Nebraska state line in an attempt to find water storage to fill a crippling water gap that is just 12 years away. According to the 2015 Colorado Water Plan, by 2030 the need for water in Colorado will exceed supplies by 560,000 acre feet, or 182 billion gallons per year, and most of that is here in the South Platte River Basin.

Experts already have said that water conservation alone won’t bridge the gap as thirsty Front Range cities continue to grow; even legislators have made it clear that they want to see proposals for storage as much as for conservation.

But, as with everything else having to do with water, finding and then using that storage is going to be complicated.

According to the SPSS report, it’s estimated that the South Platte carries almost 300,000 acre feet of water per year out of Colorado in excess of the amount needed to satisfy the South Platte River Compact with Nebraska. There are, however, a lot of “buts” that need to be attached to that broad statement.

For one thing, that’s not an average, that’s what the study authors called an “annual median.” That’s the middle number between the largest and smallest amounts that are lost; median, or “mean,” often is used instead of average because it’s a more accurate estimate of something over time.

Actual losses over a 20-year period between 1996 and 2015 varied from a paltry 10,000 acre feet to a whopping 1.9 million acre feet. It’s important to note that stream flows during that time frame included one of the largest floods in the state’s history and a follow-up flood that did nearly as much damage in the lower reaches of the river, as well as a period of extended drought.

The report also says that considerably more water is available at the Julesburg end of the reach than at the Kersey end, primarily because of return flows from irrigation. That indicates the need for a large reservoir to capture water before it leaves the state…

That may not be easy; according to the report, massive amounts of water would have to be diverted.

“Large diversion and conveyance structures would be needed to capture and convey water from the river to off-channel storage,” the study says. “At the Balzac gage near the middle of the SPSS study area, a diversion capacity of 550 (cubic feet per second) would be needed to capture 85 percent of the available water.”

That’s as much as some of the largest diversion structures now on the river. The North Sterling Inlet Canal, for instance, was taking around 520 cfs before cold weather and icing required it to be scaled back. Prewitt Reservoir Inlet can divert as much as 600 cfs when the water’s available.

It’s important to note the phrase “85 percent of available water.” Elsewhere in its recommendations section the report states that capturing all of the excess water is simply not feasible, and that’s not just during flood conditions.

“No feasible storage concepts or reasonable combinations of concepts are capable of putting all the available flow in the lower South Platte River to beneficial use,” the report says. “Therefore as a general principle, more storage will always be ‘better’ in this region in terms of maximizing available supply for basin water users.”

Still, finding and optimizing storage is a must if there is to be any hope of providing enough water to go around. The report, naturally, recommends a combination of storage methods, and even suggests that a cooperative effort of upper basin and lower basin storage concepts would be more efficient and store more water than a major “on-stem” reservoir. On the other hand, the on-stem option would be easier to build and yield more water quickly; it also faces possibly insurmountable permitting requirements.

No water storage concept is without good-versus-bad arguments. Aquifer or “underground” storage is complicated to manage but cheaper to create, and it can be easily ramped u over time. Storage options are grater in the lower basin but they’re further from where the water will actually be needed. Underground storage is great for agricultural use but the water would have to be extensively treated for municipal and industrial use.

The study even raised some new questions and left unanswered some old ones. For instance, abandoned gravel pits weren’t even included in the project, and the SPSS authors recommend further study of that option. They also recommend further studies of the South Platte above Kersey and of the Cache la Poudre basin.

Ultimately, the study’s authors say, the SPSS is a “starting point” and further investigation of any of the storage methods or sites would be needed.

“The work in the SPSS is a starting point for more specific alternative investigations,” the study says, “but substantial additional analysis will be required to test the feasibility of specific storage options based on points of diversion, intake systems, and methods of operating to meet demands.”

@ColoradoClimate: Weekly Climate, Water and #Drought Assessment of the Intermountain West

Upper Colorado River Basin month to date precipitation through December 26, 2017 via the Colorado Climate Center.

Click here to read the current assessment. Click here to go to the NIDIS website hosted by the Colorado Climate Center.

#Snowpack news: The recent storm track favored North and South Platte basins

Click on a thumbnail graphic below to view a gallery of snowpack data from the NRCS.

And here’s the Westwide SNOTEL basin-filled map from the NRCS.

Westwide SNOTEL basin-filled map December 27, 2017 via the NRCS.