One-Quarter of the World’s Population Faces High Water Stress; Arizona and Nevada Face Mandatory Water Cutbacks
“17 Countries, Home to One-Quarter of the World’s Population, Face Extremely High Water Stress.”
Figure 1: Overall Water Risk. Source: World Resources Institute.
So says the title of a report issued recently by the World Resources Institute (WRI). Behind the florid headline lies a somewhat more complex, but still very dangerous, reality.
Figure 1 maps the overall water stress. This is a statistic that combines 13 different kinds of water risks into one summary statistic. Thus, the color coding on the map does not translate directly to a physical measure of any specific threat, but rather represents the level of threat from all combined. The report discusses the risks individually, and they can be mapped using the Aqueduct tool available at the WRI. They are:
Quantity Risks Quality Risks Regulatory Risks
Baseline water stress Untreated wastewater Unimproved/no drinking water
Baseline water depletion Coastal eutrophication Unimproved/no sanitation
Groundwater table decline Peak RepRisk country EST risk
Interannual variability
Seasonal variability
Drought risk
Riverine flood risk
Coastal flood risk
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You can see that large swaths of Africa, the Middle-East, India, and China face extremely high risk. Those who read the environmental sections of the news may recall that Chennai, India (a city of over 7 million, formerly called Madras) is currently facing a severe water crisis. This city of over 7 million people reached “Day Zero” in June, when the reservoirs ran dry, and the city water company could no longer provide water. The rich pay exorbitant rates for water that is privately trucked in from hundreds of miles away, but average people get a small allocation (less than 8 gallons per day) that is brought in by the government, and they have to walk long distances to distribution points. The temperature just now in Chennai is ranging from a low of 80 to a high of 92, and the humidity is near 90%. Can you imagine living in that heat with only 8 gallons of water every day?
Those with slightly longer memories may remember that Cape Town, South Africa, faced a similar situation last year. Reservoirs hovered at 15-30% of capacity. Had levels reached 13.5% of capacity, the water company would have turned off deliveries, and people would have had to queue for water, just as in Chennai. Heavy monsoons in the summer of 2018 partially refilled the reservoirs, and “Day Zero” has been forestalled for the time being.
In both cases, the water crises were slow motion train wrecks, building slowly over years. Mismanagement and failure to perform upkeep on the water infrastructure played a role, but the primary culprit was increased population. Cape Town’s population grew from 2.4 million in 1995 to 4.1 million in 2015, an increase of 71%. Chennai’s population grew from under 1 million in 1941 to 4.3 million in 2001, and then exploded to 7 million in 2011. These population increases represented huge increases in demand, and supplies did not keep up. In both cases, however, the crises themselves were triggered by severe drought. A drought can cause the supply of water to plummet. If a region consumes almost all of its water supply, when a drought starts, the region can very suddenly find itself in a serious shortage. If the drought persists, the region will drain its reserves, and then the taps will go dry.
Given that population continues to increase, and climate change is predicted to cause longer, more severe droughts, it is a situation we are likely to see more often in the future.
Figure 2: Baseline Water Stress. Source: World Resources Institute.
Most regions of the United States are somewhat less vulnerable to pollution and eutrophication, and have access to sanitation and treated potable water. Thus, for Figure 2, I have chosen a map of Baseline Water Stress for the Continental United States, which measures total water consumption compared to total renewable water availability. On this map, Extremely High means the region consumes more than 80% of its renewable water supply, High means it consumes 40-80%, Medium High means it consumes 20-40%, Low Medium means it consumes 10-20%, and Low means it consumes less than 10%.
The areas of higher risk tend to be in the western half of the country, which should come as no surprise. The largest area of extreme risk includes California’s Central Valley, Los Angeles, San Diego, and the Imperial Valley. That should come as no surprise to readers of this blog, I’ve reported on it many times. But extreme risk is not confined to California. There are areas of extreme risk in Arizona, Utah, Eastern Washington/Oregon, New Mexico Colorado, Texas, and Minnesota. There is even one from St. Louis to Memphis, running along the Mississippi River. In all of these locations, a partial loss of water supply would quickly throw the area into deficit.
None of these areas has faced “Day Zero” in the way Cape Town and Chennai have. But they are getting close. Drought in California a few years ago led to the imposition of mandatory water restrictions, and the 2011 drought in Texas drained the E.V. Spence reservoir to 1% of its capacity, causing billions of dollars in damages, threatening the future of Robert Lee, a nearby town that depends on the reservoir.
Just 3 days ago (8/15/19) the Bureau of Reclamation announced that Arizona and Nevada will experience cutbacks in their allocation of water from the Colorado River, starting January 1. As I reported just a few weeks ago, Lake Mead is actually higher than it has been for 5 years. However, the states and countries that draw on Colorado River water have finally taken the situation seriously, and a new agreement to save Lake Mead from going dry was signed earlier this year. While the old system didn’t force cutbacks until the lake was at 1,070 feet above sea level, the new agreement starts phasing them in if the surface of the lake falls below 1,090 feet. (They measure the lake by how far above sea level its surface is. The lake is nowhere near that deep.) It is projected to be at 1,089.4 next January. Arizona will see a cutback of 6.9% of their water allocation.
It is tempting to think of the extreme crises in Chennai and Cape Town as Third World events; such things could never happen here, we might think. But the trends that caused the problems in both Chennai and Cape Town are at work in Arizona, California, Texas, and all across the West: increasing population, leading to increased demand, plus longer and harsher droughts, caused by climate change. Will they lead to similar crises? Will people be surprised and wonder how things could have gotten to such a point? I guess time will tell.
Sources
Hofste, Rutger Willem, Paul Reig, and Leah Schleifer. “17 Countries, Home to One-Quarter of the World’s Population, Face Extremely High Water Stress.” World Resources Institute. Downloaded 8/11/2019 from https://www.wri.org/blog/2019/08/17-countries-home-one-quarter-world-population-face-extremely-high-water-stress.
James, Ian. 2019. “First-Ever Mandatory Water Cutbacks Will Kick In Next Year Along the Colorado River.” azcentral.
Viewed online 8/18/2019 at https://www.azcentral.com/story/news/local/arizona-environment/2019/08/15/colorado-river-water-drought-arizona-nevada-mexico-first-ever-reductions/2021147001.
U.S. Bureau of Reclamation. Reclamation Announces 2020 Colorado River Operating Conditions. Downloded 8/18/2019 from https://www.usbr.gov/newsroom/newsrelease/detail.cfm?RecordID=67383.
Wikipedia contributors, “Cape Town water crisis,” Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Cape_Town_water_crisis&oldid=911322360 (accessed August 18, 2019).
Wikipedia contributors, “2019 Chennai water crisis,” Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=2019_Chennai_water_crisis&oldid=910798196 (accessed August 18, 2019).
World Resources Institute. Aqueduct Water Risk Atlas. Maps downloaded 2019-08-18 from https://www.wri.org/aqueduct.
Does Southwest Missouri Face a Future Water Shortage?
Southwest Missouri faces a water crisis. If nothing is done, demand will exceed current supply by 2030. However, sufficient additional water to meet demand through 2060 appears to be available, and could be accessed at a relatively low cost. Whether doing so would impact the regions ecosystem is not known.
In the previous post, I reported that current stresses on water supply along the Missouri River depend primarily on human decisions about how to manage competing demands for the river’s water. The future effects of climate change are not yet known.
What about regions of the state that don’t depend on the Missouri River for their water supply? Are demands projected to exceed supply?
To answer that question, we must start by distinguishing between water resources and water supply. Water resources consist of the total water available in a region. Water supply is the amount of water that the infrastructure is capable of delivering.
Water resources consist of surface water and groundwater. Some regions of the state depend primarily on surface water. In fact, surface water supplies 8 of Missouri’s 10 largest cities, and 62% of the state’s total water consumption (44% from the Missouri River alone). Groundwater supplies about 38% of Missouri’s water consumption. Some regions, however, rely more heavily on groundwater, especially in the southern part of the state.
Figure 1. Southwest Missouri Counties Expected to Experience a Future Water Shortage. Source: Adapted from a map at Wikimedia Commons.
No region of the state is currently experiencing a sustained shortfall in water supply compared to demand. Perhaps the region most likely to experience one in the future is a 16 county area in Southwest Missouri. Figure 1 shows a map of the 16 counties.
The region has historically depended primarily on groundwater, as it is underlain by the Ozark Aquifer. Aquifer levels fluctuate depending on how much precipitation occurs to recharge them. In addition, over-pumping can deplete the water supply in a local region of the aquifer faster that water can flow in to replace it, causing a cone of depression. It can leave neighboring wells high and dry, but does not affect the whole aquifer. Severe over-pumping from multiple sources can deplete the entire aquifer, which is occurring in California.
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Figure 2. Missouri Population Density. Source: Tri-State Water Coalition.
The region’s constraints on water supply have occurred because of growth. Figure 2 is a map of population density in Missouri. It shows that Southwest Missouri is one of the more densely populated regions.
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Figure 3. Source: Tri-State Water Resource Coalition.
Figure 3 shows that from 1990-2000 the region was the fastest growing in the state. Between 2000 and 2010, the trend continued, with Christian County growing an astounding 43% and Taney County growing by 30%.
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Figure 4. Source: Tri-State Water Resource Coalition
The result has been over-pumping, and Figure 4 shows the results. In Southwest Missouri, most areas have experienced some decrease in the groundwater level. A few regions in Green County (the City of Springfield), Jasper County (the City of Joplin), and Stone and Taney Counties (the Branson area) have experienced cones of depression, dropping the water table more than 300 feet. The worst affected area is the large red area on the left side of the map. It is in Oklahoma, centered on Miami, OK.
Using a mid-level growth forecast, studies have calculated that current water resources will be overrun by demand by 2030. Even reducing demand through conservation would only meet needs through 2040.
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Figure 5. Projected Water Demand and Supply by 2060 in a Drought Year. Source: Tri-State Water Resource Coalition.
The region has significant surface water resources, however, and could supplement its water supply. Three significant reservoirs could supply water to the region: Stockton Lake, Table Rock Lake, and Lake Taneycomo. The first two are operated by the U.S. Army Corps of Engineers, and the latter is owned and operated by Empire District Electric Company. These organizations would have to approve the reallocation of water, but the water is there. Figure 5 shows projected available supply and demand if surface water resources were tapped. It would require the construction of pipelines and pumping stations, but the dams and reservoirs already exist.
Climate change is not projected to cause a decrease in precipitation in the region. The worst drought on record occurred in the 1950s, and if anything, the trend in precipitation has increased slightly since 1895. The temperature is projected to increase significantly, however. If increased temperature were to lead to less water reaching the aquifer to recharge it, then it could have implications for the regions water supply. But so far, those projections have not yet been calculated.
Unfortunately, none of the reports I contacted discuss the environmental impacts that the increasing demand for water will place on the ecosystem in the region. In fact, so far as I could tell, possible effects were not even considered. Will dropping water tables cause springs, creeks, and rivers to go dry? Will reallocation of the water from the regions reservoirs affect the health of the White and Osage Rivers? Will subsidence occur? These effects have occurred elsewhere, why Missouri would expect to be immune from them? But I just don’t know.
Thus, it appears that Southwest Missouri does face a water crisis. If nothing is done, demand will exceed current supply by 2030. However, sufficient additional water to meet demand through 2060 appears to be available, and could be accessed at a relatively low cost. Whether doing so would impact the regions ecosystem is not known.
Sources:
Missouri Department of Natural Resources. Springfield Plateau Groundwater Province. Downloaded 5/23/2017 from https://dnr.mo.gov/geology/wrc/groundwater/education/provinces/springfieldplatprovince.htm?/env/wrc/groundwater/education/provinces/springfieldplatprovince.htm.
State of Missouri and U.S. Army Corps of Engineers. 2012. Southwest Missouri Water Resource Study – Phase I. Downloaded 5/23/2017 from http://www.swl.usace.army.mil/Portals/50/docs/planningandenvironmental/Phase%20I%20-%20Southwest%20Missouri%20Water%20Study%20Final%20Report%20.pdf.
State of Missouri and U.S. Army Corps of Engineers. 2014. Southwest Missouri Water Resource Study – Phase II. Downloaded 5/23/2017 from http://tristatewater.org/wp-content/uploads/2014/11/Phase-II-FINAL-Southwest-Missouri-Supply-Availability-Report-Final_March_2014-from-Mike-Beezhold-9-16-14.pdf.
Tri-State Water Resource Coalition. 2015. Securing Water for Southwest Missouri. Downloaded 5/30/2017 from https://waterways.org/wordpress1/wp-content/uploads/2015/05/Securing-Water-for-Southwest-Missouris-Future.pdf.
Will Climate Change Affect Water Supply on the Missouri River?
How climate change will affect water supply from the Missouri River is not yet known. Current problems with Missouri River water supply principally affect the barge transportation industry, and the agricultural and industrial clients that use it to transport their goods and supplies.
The Missouri River is important for Missouri. More than half of Missouri residents get their drinking water from the Missouri River or the alluvial aquifer it directly feeds. Not only that, the river’s water is used for agricultural irrigation, for industry, to support barge traffic along the Missouri and Mississippi Rivers, for recreation, and to support the ecosystems that depend on the river for their survival.
Figure 1. Dams and Other Locations Along the Missouri River. Source: Google Earth.
In the previous post, I reported that the snowpack in the western United States has declined by 23%, and it is forecast to decline more by 2038. The eastern border of the study area forms the western boundary of the Missouri River Basin. Will the changing western snowpack impact the Missouri River’s ability to supply Missouri’s needs?
The answer is complicated. Precipitation in the Upper Missouri River Basin has historically fallen mostly as snow, building a winter snowpack that slowly melts during the spring. The snowmelt is gathered into reservoirs created by 6 large dams along the Missouri River, plus more than 40 smaller ones on tributaries. The 6 large dams begin at the Gavin’s Point Dam on the Nebraska-South Dakota border, and extend upriver to the Ft. Peck Dam in Montana. (See Figure 1.) The result is that water flow below the reservoirs is largely controlled by man, not nature.
Figure 2. Data source: Wikipedia.
The annual water yield from the Missouri River is small compared to the size of its basin. The data is given in Figure 2, where the red columns represent the length of the rivers, and the blue line represents their average discharge. No other river in the USA serves such a large basin with so little water. In drought years it is already too small to fully meet all of the demands that are put on it, resulting in conflict over how to manage the river, and over which values to give priority. The conflict has primarily been between up-river interests, which would like to see water allocated to support irrigation, drinking water, and mitigation in their states during periods of drought, and down-river interests, which would like to see water released to support commercial navigation on the river.
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Figure 3. Source: Hansen Professional Services, Inc. 2011.
In 2004, the Army Corps of Engineers changed the rules by which the river is operated to reduce water releases during drought. During drought years, this better supports up-stream interests, but results in a shorter season during which the river can support barge traffic. The result has been a decrease in annual tonnage moved on the river (Figure 3).
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Figure 4. Well Drilling in Western North Dakota. Source: Vanosdall 2013.
In addition, development in the Upper Missouri Basin has increased water demand in that region. A prime example would be the development of the oil and gas reserves in North Dakota. Well drilling uses large quantities of water. (See Figure 4). Given that the water yield from the Missouri River is already too small to fully support all of the demands placed on it, any increase in demand is bound to constrain supply even further.
The constraints discussed above, however, are all man-made constraints. How will climate change and the declining western snowpack affect all of this?
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Source: National Centers for Environmental Information.
The snowpack decline has occurred because of increasing temperature, not decreasing precipitation. Figures 5 repeats a chart I published in January 2016, showing that precipitation has increased in the region over time.
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Figure 6. Source: Melillo 2014.
Figure 6 shows that the 2011 National Climate Assessment projects that the annual flow on the Missouri River will actually increase by about 15% by 2070. However, more precipitation will fall as rain instead of snow, and the snow that does fall will melt sooner. This means that more water will enter the reservoirs during winter and early spring, and less during late spring and summer. In addition, increased temperature will increase evaporation from the river and reservoirs, and it will increase water consumption by crops, leading to earlier and increased demand for water. There is a potential mismatch between when the water is available and when it is needed.
The question will be whether it will be possible to manage the reservoirs successfully under the new conditions. When looking at the water situation in California (here), we discovered that water authorities expected climate change to create reservoir management problems that would result in an increased water deficit during the summer and autumn. It is possible that the reservoirs along the Missouri will encounter similar problems, but it is not certain.
One potential difference is that California has multiple, relatively short rivers, leading to only one large reservoir per river, and perhaps one or two small feeder reservoirs. The Missouri River, however, is a single long river. It has 6 large reservoirs chained along it, plus at least 40 feeder reservoirs on tributaries. This may give managers flexibility in managing the river that is not possible in California.
Five separate water resource studies have been undertaken to determine how climate change will impact the ability of the Missouri River to meet the demands placed on it. Unfortunately, they have not all been completed, and I can find no comprehensive analysis.
For the time being, problems with water supply on the Missouri River involve human decisions about how to manage the river. To date, in the State of Missouri they have primarily impacted the barge industry, plus the farmers and industries that depend on the barge industry to transport their goods and supplies.
Sources:
Drew, John, and Karen Rouse. 2006. “Missouri Water in High Demand.” Missouri Resources, Winter, 2006. Downloaded 5/31/2017 from https://dnr.mo.gov/geology/wrc/docs/Water-InHighDemand.pdf?/env/wrc/docs/Water-InHighDemand.pdf.
Bureau of Reclamation. 2016. Basin Report: Missouri River. Downloaded 5/25/2017 from https://www.usbr.gov/climate/secure/docs/2016secure/factsheet/MissouriRiverBasinFactSheet.pdf.
Bureau of Reclamation. 2016. SECURE Water Act Section 9503(c) – Reclamation Climate Change and Water. Prepared for United States Congress. Denver, CO: Bureau of Reclamation, Policy and Administration. Downloaded 5/25/2017 from https://www.usbr.gov/climate/secure.
Hanson Professional Services, Inc. 2011. Missouri River Historic Timeline and Navigation Service Cycle. Missouri River Freight Corridor Assessment and Development Plan. Downloaded 5/31/2017 from https://library.modot.mo.gov/rdt/reports/tryy1018.
Melillo, Jerry M., Terese (T.C.) Richmond, and Gary W. Yohe, Eds., 2014: Climate Change Impacts in the United States: The Third National Climate Assessment. U.S. Global Change Research Program, 841 pp. doi:10.7930/J0Z31WJ2. Available online at http://nca2014.globalchange.gov.
Vanosdall, Tiffany. 2013. Missouri River Water Supply. US Army Corps of Engineers. Downloaded 6/1/2017 from https://denr.sd.gov/coewatersupply22Apr2013.pdf.
Wikipedia. List of U.S. Rivers by Discharge. Data retrieved online 5/31/2017 at https://en.wikipedia.org/wiki/List_of_U.S._rivers_by_discharge.
Declining Snowpack in the American West
The snowpack over the western United States has declined about 23% since 1981. It is projected to decline more in the future.
I have written a number of posts about the looming water deficit in California due to a projected decline in the snowpack on the Sierra Nevada mountains. Is something similar projected to occur throughout the entire western United States?
Figure 1. Change in Snow Water Equivalent at SNOTEL Stations, 1955-2016. Source: Mote and Sharp 2016, in Environmental Protection Agency, 2016.
Yes. Studies find that the water content of the snowpack throughout the West has already declined 23%, and it is expected to decline more, perhaps up to 30% by 2038.
This decline is not occurring via a decrease in precipitation. Indeed, to date precipitation across the West has actually increased slightly. The decline is occurring due to increased temperature. Some precipitation that used to fall as snow now falls as rain, and the snow that does fall melts more quickly.
Mote and Sharp studied the snow water equivalent* of the snowpack in April from 1955-2016 at SNOWTEL measuring stations operated by the U.S. Natural Resource Conservation Service. Figure 1 shows a map of the stations, with blue dots representing stations where the snowpack increased and orange dots representing stations where the snowpack declined. The size of the dots represent the magnitude of change.
It is easy to see that the vast majority showed declines in the snowpack, in many cases by as much as 80%. Overall, Mote and Sharp computed that there had been an average 23% decline in the western snowpack since 1955.
Figure 2. Observed and Modeled Change in Snowpack. Source: Fyfe, et al, 2017.
Fyfe and his colleagues conducted climate modeling to try to determine whether the decline in the snowpack was due to natural causes or human causes. Figure 2 shows the results in a rather complicated graph. Let’s unpack it. The computer models ran from 1950 to 2010. The dashed black line shows the observed trend in the snow water content. The solid blue line shows the projected snow water content if only natural climate causes are included in the model. It doesn’t fit the observed trend very well. The solid black line shows the projected snow water content if both natural and human climate causes are included in the model. It fits the observed data quite closely. (The pink and green lines show data from analyses using other sets of data and need not concern us here. The gray band and blue dotted lines show statistical confidence levels for the computer simulations, and also need not concern us here.)
The simulation that included both natural and human causes agreed with the observed data, but the one that included only natural causes did not. The authors concluded that natural causes could not explain the loss of snowpack in the West. A combination of human and natural causes could explain it.
Figure 3. Projected Short-Term Change in Snowpack. Source: Fyfe, et al, 2017.
Fyfe and his colleagues also conducted a suite of climate models to project snowpack loss into the future. The results are shown in Figure 3. In this graph, the y-axis represents the actual snow water content of the snowpack, not the change. The blue line represents the computer model that projected the least snowpack loss in 2030, and the red line represents the computer model that projected the most loss. It is common practice among climate modelers to run a suite of projections, and when this is done, the average of them is often also presented, and it is often taken as likely to be the most accurate. In Figure 3, the average of the projections is represented by the black line.
It is easy to see that the trend in all of the lines is down. There is considerable variation from point-to-point in the red and blue lines, indicating that the projections expect there to be considerable variability in the snowpack from year-to-year. The black line is pretty smooth, however, as might be expected from an average of several analyses, and it has a consistent downward trend. The losses in snowpack in some of the projections ran as high as 60%, though average loss across the suite of projections was about 30%.
A 30% decline in the snowpack does not sound so dire; after all the projections are for a 60% loss of snowpack in California (see here). However, that projection was for the end of the century. This projection is for 2038; that’s only 20 years from now.
Some may wonder about how little snow water equivalent is shown on the y-axis of Figure 3. In the 1990s, the snowpack maxed-out each year at only 6+ cm. of snow water equivalent. In thinking about this number, remember two things: first, a centimeter of water represents somewhere between 3 and 20 centimeters of snow, with an average value being somewhere around 10 cm. Thus, 6 cm. of snow water equivalent would roughly equal 60 cm. of snow, or 23.6 inches. Thus, the average depth of the snowpack was about 2 feet. Second, remember that the measurements were averaged across hundreds of locations; some were high and received a great deal of snow, but some were relatively low (low altitude means more rain, less snow), or were located in areas that don’t receive much precipitation of any kind.
Much of Missouri depends on the Missouri River as a water supply, including both Kansas City and St. Louis. The Missouri River gets much of its water from the western snowpack. A declining snowpack may, or may not, have implications for our water supply, depending on whether the reservoirs along the Missouri River can accommodate the shift toward earlier snowmelt and increased rain. I will look at this issue in the next post.
* Snow water equivalent: Different types of snow hold different amounts of water. Thus, scientists don’t just measure how deep the snow is. Rather, at a given location they take a representative sample of the snowpack and melt it, thereby determining how much water it holds. This is the snowpack’s snow water equivalent at that given location. April is generally when the snowpack is at its maximum.
Sources:
Environmental Protection Agency. 2016. Climate Change Indicators in the United States: Snowpack. Retrieved online 5/22/2017 at https://www.epa.gov/sites/production/files/2016-08/documents/print_snowpack-2016.pdf.
Fyfe, John, Chris Kerksen, Lawrence Mudryk, Gregory Flato, Benjamin Santer, Neil Swart, Noah Molotch, Xuebin Zhang, Hui Wan, Vivek Arora, John Scinocca, and Yanjun Jiao. 2017. “Large Near-Term Projected Snowpack Loss Over the Western United States.” Nature Communications, DOI: 10.1038/ncomms14996. Retrieved online 5/14/2017 at https://www.nature.com/articles/ncomms14996.
California Drought Emergency Officially Over
Gov. Jerry Brown officially declared California’s drought emergency over on Friday, April 7. It was a fitting ending to one of the worst episodes in California’s drought-laden history.
Or was it? The next two posts update California’s water situation. This one focuses on the current short-term situation. The next one focuses on the future, with an eye toward the future impact of climate change. I have personal reasons for following California’s water situation – I have family living there. But in addition, California is the most populous state in the Union, it has the largest economy of any state, and the state grows a ridiculously large fraction of our food. What happens in California affects us here in Missouri.
Figure 1. California Snowpack, 3/31/2017. Source: California Department of Water Resources.
Is the short-term drought truly over? Yes, I think so. The vast majority of California’s precipitation falls during the winter, and the snowpack that builds up in the Sierra Nevada Mountains serves as California’s largest “reservoir.” As it melts, it not only releases water that represents about 30% of the state’s water supply, but it also feeds water into the underground aquifers that provide groundwater to much of the state. Thus, the size of the snowpack is the most important factor in determining California’s water status. California measures the water content of the snowpack electronically and manually. The measurements around April 1 are considered the most important, as that is when the snowpack is typically at its largest. Figure 1 shows the report for this year. Statewide, the water content of the snowpack was 164% of average for the date, almost 2/3 larger than average. The water content was significantly above average in all three regions of the snowpack, North, Central, and South.
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I follow the snow report at Mammoth Mountain Ski Resort to provide a specific example of the snow conditions. Figure 2 shows that through March, Mammoth received over 500 inches of snow, one of the highest totals in the record going back to 1969-70. The column for 2016-17 has very large blue and orange sections, indicating that the majority of the snow fell in January and February. Figure 3 confirms the impression. It charts the amount of snowfall at Mammoth during each month of the 2016-17 snow season, and compares it to the average for that month across all years. You can see that both January and February were monster snow months, especially January. By March, snowfall had already fallen below average. I wouldn’t make too much of this fact, one month doesn’t make a trend.
Figure 2. Source: Mammoth Mountain Ski Resort.
Figure 3. Data source: Mammoth Mountain Ski Resort.
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Figure 4. Source: California Data Exchange Center.
California also stores water in man-made reservoirs. Figure 4 show the condition of 12 especially important ones on March 31. Most were above their historical average for that date, and many were approaching their maximum capacity. Those who follow this blog know that the Oroville Reservoir actually received so much water that it damaged both the main and emergency spillways, threatening collapse of the dam and requiring evacuation of thousands of people down stream. (See here.)
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Figure 5. Elevation of the Surface of Lake Mead. Source: water-data.com.
In addition, Southern California receives the lion’s share of water drawn from the Colorado River, thus the status of Lake Mead, the largest reservoir on the Colorado, is important to the state. A study in 2008 found that there was a 50% chance the reservoir would go dry by 2021. On March 31, Lake Mead was at 1088.26 feet above sea level. (This doesn’t mean there were that many feet of water in the reservoir, Hoover Dam isn’t that tall. Rather, it represents how many feet above sea level the surface of the water was. Lake Mead’s maximum depth is 532 feet.) The current level represents 41.38% of capacity. Figure 5 shows the level of the lake over time. You can see that the line tends to go up with the spring snowmelt, and down during the rest of the year. This year it is up very slightly year-over-year, but the trend has been relentlessly down since 2000.
The conclusion seems inescapable: for this year at least, California has plenty of water. The short-term drought is over. One year doesn’t make a climate trend, however. In the next post I will consider the implications of this wet winter for California’s water situation going into the future.
Sources
Barnett, Tim, and David Pierce. 2008. “When Will Lake Mead Go Dry?” Water Resources Research, 44, W03201. Retrieved online at http://www.image.ucar.edu/idag/Papers/PapersIDAGsubtask2.4/Barnett1.pdf.
CA.GOV. Governor Brown Lifts Drought Emergency, Retains Prohibition on Wasteful Practices. Viewed online 4/10/2017 at https://www.gov.ca.gov/home.php.
California Data Exchange Center. Conditions for Major Reservoirs: 31-Mar-2017. Viewed online at http://cdec.water.ca.gov/cdecapp/resapp/getResGraphsMain.action.
California Department of Water Resources. Snow Water Equivalents (inches) for 3/30/2017. Viewed online 3/31/2017 at http://cdec.water.ca.gov/cgi-progs/snowsurvey_sno/DLYSWEQ.
Mammoth Mountain Ski Resort. Snow Conditions and Weather, Extended Snow History. Data downloaded 4/2/2017 from http://www.mammothmountain.com/winter/mountain-information/mountain-information/snow-conditions-and-weather.
water-data.com. “Lake Mead Daily Lake Levels.” Downloaded 4/5/2017 from http://graphs.water-data.com/lakemead/.
Missouri’s Water Consumption Decreasing Slower Than the Nation’s
Missouri’s water consumption declined in 2010. The decline was smaller than the decline for the nation as a whole, and it may be due to economic factors rather than conservation.
Missouri is not one of the regions of the country where water supplies are most tightly constrained. Thus, Missouri is not under as much pressure to reduce consumption as some states are, California for instance. Nevertheless, water consumption is an important environmental variable, and it is useful to know what the trends are in Missouri.
The data for this post comes from the U.S. Geological Survey’s Water Use Data for the Nation data portal. The portal’s data for Missouri extends back to 1985.
Figure 1. Data source: USGS Water Use Data for the Nation.
Figure 1 shows Missouri’s water consumption by end use, including thermoelectric power, for 1985-2010. Missing data makes comparisons across years difficult: data for thermoelectric power is missing for 1985, and data for livestock is missing for 1985, 1990, and 1995. With those caveats, Missouri’s water consumption appears to have increased through 2005, and then declined slightly in 2010. This contrasts with national consumption, which peaked in 1980.
The decline in 2010 may represent the beginning of a trend, but before assuming that it does, recall that 2010 was during the depths of the Great Recession, and the decline in water consumption may be related to a decline in economic activity, not conservation efforts.
Thermoelectric power is by far the largest consumer of water in Missouri. Missouri’s largest power plants (Labadie, Iatan, Thomas Hill, Rush Island, New Madrid, Sioux, Hawthorne, Meramec, and Callaway) are all located on rivers or reservoirs, and they withdraw water for cooling and for making steam. Thermoelectric water withdrawals peaked in 2005 at 6,181 million gallons per day, and declined in 2010 to 5,915 million gallons per day, a decline of 4%.
Irrigation was the second largest consumer of water in Missouri. The peak year for irrigation consumption was 2000 at 1,431 million gallons per day, and it was about 2% lower in 2010 at 1,402 million gallons per day.
Figure 2. Data source: USGS Water Use Data for the Nation
Figure 2 shows Missouri’s water consumption by end use with thermoelectric power excluded. I think that thermoelectric power is not a proper end use for two reasons. First, most water withdrawn for thermoelectric power is used for cooling, and it is returned to the environment. When returned, it may cause local problems because it is hot, but generally it is not contaminated. Second, electricity is not generated for its own use, it is sold to customers for their end uses. Thus, it may be useful to understand Missouri’s water consumption with thermoelectric power excluded.
Once thermoelectric power is excluded, irrigation and public supply become by far the largest consumers of water in Missouri. Irrigation was discussed above. Public supply represents all water that is delivered to customers by a public water utility. Here, things get a little complex. Some domestic and industrial water consumers supply their own water themselves. These consumers represent a small fraction of the total, and are shown on the chart in red and green. Most domestic and commercial consumers, and some industrial consumers, are supplied water by public water utilities, and these are the consumers represented by the dark blue public supply category on the chart. Both irrigation and public supply peaked in 2000, and by 2010 had declined 2% and 4% respectively. Because the trend is consistent from 2000 to 2005 to 2010, I am less inclined to suspect it is a function of the Great Recession.
Figure 3. Data source: USGS Water Use Data for the Nation
Stacked column charts are great for showing categorized data over time, but pie charts show more dramatically the percentages belonging to each category in a given year. Figure 3 shows Missouri water consumption in 2010 by end use, thermoelectric power included. It shows that thermoelectric power accounted for 70% of all Missouri water withdrawals. Irrigation accounted for 17% and public supply for 10%. Together, the three accounted for 97% of Missouri water withdrawals.
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Data source: USGS Water Use Data for the Nation
Figure 4 shows the same data with thermoelectric power excluded. If one considers thermoelectric power withdrawals a non-consumptive use, then irrigation and public supply together accounted for 91% of the water consumed in Missouri in 2010.
Because of the drought in California, I have also been following water supplies out there. I will post on California’s water situation after the start of the new year.
Sources:
Maupin, M.A., Kenny, J.F., Hutson, S.S., Lovelace, J.K., Barber, N.L., and Linsey, K.S., 2014, Estimated use of water in the United States in 2010: U.S. Geological Survey Circular 1405, 56 p., http://dx.doi.org/10.3133/cir1405.
U.S. Geological Survey. 2014. Water Use Data for the Nation. USGS National Water Information System. Search criteria: Years 1965,1970,1975,1980,1985,1990,1995,2000,2005,2010; Area UNITED STATES; Catogory ALL. Data accessed 12/3/2016 at http://waterdata.usgs.gov/nwis/wu.
USA Water Consumption Declined in 2010
Water consumption in the United States declined 18% between 1980 and 2010.
Water consumption is an issue of concern in areas where water supplies are constrained. Constructing a comprehensive study of how much water is consumed in the United States is a gargantuan task, but the United States Geological Survey does it every five years. It takes several years to put together, and the report Estimated Use of Water in the United States in 2010 came out in 2014. Historical data are also available on the USGS National Water Data Information System data portal.
Data source: USGS Water Use Data for the Nation
Figure 1 shows that water consumption in the USA grew rapidly from 1965 to 1980, but since then has declined. The peak in 1980 was 430 billion gallons consumed per day and by 2010 it had declined 18% to 355. The decline occurred despite the fact that during the period Gross Domestic Product grew by 229% and population grew by 36%.
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Data source: USGS Water Use Data for the Nation
Figure 2 shows similar data, except it is separated into end uses. The shape of the trend matches the one in Figure 1. It is impossible, however, to separate water consumption by end use without either missing some that you should count, or double counting some that you shouldn’t. The result is that, for any given year, if you total the amount used by each end use in Figure 2, it won’t precisely match the amount shown in Figure 1. The disagreement is small, never as much as 5%, and often much smaller than that. It would probably matter if you were doing research, but for our purposes here, it probably doesn’t.
Figure 2 shows that more water is withdrawn for thermoelectric power (nuclear and coal-burning power plants, primarily) than for any other use. Second is irrigation. Both have decreased since 1980. I don’t know the precise reasons why, but if I had to guess, I would say that retiring nuclear and coal-burning power plants in favor of natural gas and renewable energy, improved irrigation practices, and switching to soil cover/crops that require less water were all part of the story.
Public Supply did not peak in 1980, it increased right through to 2005. That makes sense, given that population and GDP have increased. Public supply includes all water delivered by a public water utility.
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Data source: USGS Water Use Data for the Nation
I don’t consider water withdrawn for thermoelectric power to be a true end use. For one reason, it is returned to the environment and used again without much treatment. For another, electricity is not generated for its own use, it is provided to customers for their end uses. Thus, it might be useful to look at water consumption with thermoelectric power excluded. Figure 3 shows the data. Now it becomes clear just how much of our water consumption really goes to irrigation: 60-67% in any given year. And suddenly, public supply looks more significant, accounting for up to 24% of consumption. Industry has made impressive progress in reducing water consumption.
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Data source: USGS Water Use Data for the Nation
Figure 4 shows water consumption by the source of the water: fresh or saline, surface water or groundwater. By far the largest amount is sourced from fresh surface water, and the second largest amount is sourced from fresh groundwater. If dry regions of the country turn to desalination to augment their water supply, look for the saline fraction to grow.
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Data source: USGS Water Use Data for the Nation
One final chart: these stacked column charts are good for showing categorized data over time, but they don’t show the categories for any given year as powerfully as does a pie chart. So Figure 5 is a pie chart showing water consumption in the USA by end use, thermoelectric power included, for 2010. It very powerfully shows that almost half of all water withdrawn in the USA that year went into nuclear and coal-burning power plants. About 1/3 of it went for irrigation.
In the next post I’ll look at water consumption in Missouri. I’m going to take a week off for the holiday, however, so it will appear in January.
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Sources:
Bureau of Economic Analysis. Current Dollar and Real GDP. National Economic Accounts. Downloaded 12/4/2016 from http://www.bea.gov/national/index.htm#gdp.
Maupin, M.A., Kenny, J.F., Hutson, S.S., Lovelace, J.K., Barber, N.L., and Linsey, K.S., 2014, Estimated use of water in the United States in 2010: U.S. Geological Survey Circular 1405, 56 p., http://dx.doi.org/10.3133/cir1405.
U.S. Census Bureau. Part II. Population of the United States and Each State: 1790-1990. Downloaded from http://www.census.gov/population/www/censusdata/Population_PartII.xls.
U.S. Census Bureau. 2011. Table 1. Intercensal Estimates of the Resident Population for the United States, Regions, States, and Puerto Rico: April 1, 2000 to July 1, 2010 (ST-EST00INT-01. Downloaded from http://www.census.gov/popest/data/intercensal/national/nat2010.html.
U.S. Geological Survey. 2014. Water Use Data for the Nation. USGS National Water Information System. Search criteria: Years 1965,1970,1975,1980,1985,1990,1995,2000,2005,2010; Area UNITED STATES; Catogory ALL. Data accessed 12/3/2016 at http://waterdata.usgs.gov/nwis/wu.
Final California Snowpack Reading: Below Average
I’ve been keeping a watch on the snowpack in California this winter. The snowpack is California’s most important source of water. It matters for Missouri because of the important role California plays in the national economy and in our food supply.
Figure 1: Statewide California Snowpack Water Content, 3/30/16. Data source: California Department of Water Conservation
On March 30 this year, the water content of the snowpack was 87% of its historical average for that date. Last year on April 1 it was virtually nonexistent (Figure 1). The period around April 1 is when the snowpack is at its peak, and the amount of water in it now determines how much water California will have during the dry summer and fall months.
(Click on chart for larger view.)
Eighty-severn percent is obviously better than 5%. However, it is still below average. Water officials were hoping for a larger than average snowpack to begin reversing the multi-year drought the state has experienced. It was a winter with a very large El Niño, and those years typically bring California lots of precipitation, including lots of snow in the Sierra Nevadas.
Figure 2. Data source: Mammoth Mountain Ski Resort
Snowfall data from Mammoth Mountain, one of California’s largest ski resorts, indicates an above average snowfall through March 31: a cumulative 342 inches of snow, vs. 304 in an average year. (Figure 2) Statewide data from Climate at a Glance suggests that precipitation throughout the state was 0.54 inches above average.
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Figure 3. Data source: National Centers for Environmental Information
If California received above average precipitation, yet has a below average snowpack, then one of the causes must have been a warm winter, causing the snow to melt. Indeed, as Figure 3 shows, California had a warmer than usual winter, 2.4°F above average.
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Figure 4. Data source: California Department of Water Resources
California’s man-made reservoirs are in better shape than last year. As Figure 4 shows, Lake Shasta and Lake Oroville water levels are above historical averages. (The red lines show the historical average for this date, the blue bars the current level of the reservoir. The yellow bars show the reservoir’s total capacity.) Some reservoirs, especially ones farther south, are still quite low.
Notice how near the top of the yellow bar some of the red lines are. California’s reservoirs, especially the big northern ones, are typically pretty full at this time of year. Typically, California does not receive very much rain from now through the end of November. As water is drawn out of the reservoirs to service California’s needs, snowmelt from the snowcap flows into the reservoirs to recharge them. This process is largest during the spring, but it continues at reduced rates all summer and into the fall. A small snowpack means that there is less water to recharge the reservoirs when California needs it most.
Lake Mead is at its lowest level in the last 10 years for this time of year.
California has seen a partial easing of the very severe drought of the previous two years, but nothing to signal the drought’s end. This was supposed to be a wet winter leading to an above average snowpack, but because of increased temperatures, the snowpack was below average. The El Niño is now weakening and is forecast to end by summer. What will happen then, nobody knows. Lake Mead continues to lose water. Long term, California continues to face serious challenges regarding its water supply.
Sources:
California Department of Water Resources. 2016. Conditions for Major Reservoirs: 05-APR-2016. Downloaded 4/6/16 at http://cdec.water.ca.gov/cdecapp/resapp/getResGraphsMain.action.
Water-data.com. 2016. Lake Mead Water Database. Database accessed 4/6/16 at http://lakemead.water-data.com.
National Centers for Environmental Information. 2016. Climate at a Glance. This is a data portal. Accessed 4/6/16 at http://www.ncdc.noaa.gov/cag/time-series/us.
Water Scarce for 2/3 of World’s Population
Two-thirds of the world’s population lives under severe water scarcity at least 1 month of the year, according to a study published in Science Advances. That’s 4 billion people. Nearly half-a-billion face severe water scarcity all year round.
The study’s authors divided the globe into small squares, roughly 50 kilometers on a side. Within each square, they calculated the ratio of the demand for water divided by the supply available. Ratios above 1.0 indicate areas where demand exceeds supply. Ratios below 1 indicate areas where supply exceeds demand.
Source: Mekonnen & Hoekstra, 2016.
There are a number of ways to consider water scarcity. One would be an annual summary – how does the average yearly demand compare to the average yearly supply? Figure 1 shows the data, with dark red areas having the biggest water deficit, and dark green areas having the biggest water surplus. One could guess the areas of greatest water deficit: the world’s great deserts. If there are surprises here, it is how much of the globe is red. Close to home, the size of the red area in North America is surprising, and a bit daunting.
(Click on chart for larger view.)
Source: Mekonnen & Hoekstra 2016.
Annual averages may not be the best way to consider water scarcity, however. In regions with monsoonal weather patterns, like India, Africa, or California, there may be copious water during part of the year, and severe dryness during other parts. Figure 2 shows the number of months per year that the water ratio exceeds 1.0, that is, the number of months demand exceeds supply. Dark red equals 12 months, or the whole year. Green equals 0 months, or none of the year. You can see that many of the same regions experience a water deficit for at least 6 months per year. Look at North America – how much of Canada, Mexico, and the United States experiences a water deficit a significant portion of each year! And it includes some surprising areas, such as Florida, Georgia, the Carolinas, Arkansas and Louisiana, etc.
Source: Mekonnen & Hoekstra 2016.
Finally, one can look at water scarcity seasonally, as shown in Figure 3. The top map shows the data for winter, the second map for spring, the third for summer, and the fourth for fall. There are regions of the world that experience water scarcity year-round, like the Sahara Desert and Saudi Arabia. But if you look at China/Central Asia and North America, you can clearly see a seasonal pattern. In these regions, water scarcity is at its highest in spring and summer.
It is hard to locate Missouri on these maps, it would appear to straddle the line between water surplus and water deficit. I know of no similar studies that address the situation here in more detail. In previous posts I’ve seen no sign that the state as a whole faces a significant water deficit: neither flow on the Missouri River nor statewide precipitation seem to be declining.
If your region of Missouri faces a significant water deficit, or if you know of a study of statewide water supply, why not comment and let us know? Thanks.
Source:
Mekonnen, Mesfin, and Arjen Hoekstra. 2016. “Four Billion People Facing Sever Water Scarcity.” Science Advances. 2016, 2. Downloaded on 2/13/16 from http://advances.sciencemag.org/content/2/2/e1500323.
California Water Update
It is mid-February, and I promised that I would catch up with the water conditions in California. Over the summer of 2015 I ran a 13-post series on the drought in California, in which I attempted to estimate whether California would be able to cover its future water deficit, and if not, what it would do to California’s economy.
I concluded that California faced not only a severe current drought, but a future in which they would lose a significant fraction of their water supply, resulting in a severe water deficit. Various remedies would cover only part of the deficit. The combined consequences of the shortage and the remedies would throw the state into a recession, possibly even a depression. The series of posts starts here.
I’m neither a hydrologist nor an economist, and I learned a lot as I wrote the series. I still know of no other analysis that attempts such a comprehensive assessment of California’s water future.
About the time I finished the series, signs were increasing that a large El Niño event was starting. Large El Niños typically bring above average precipitation to California. The most important form of precipitation for California is the snowpack in the Sierra Nevada and Cascades. This forms a “reservoir” that melts slowly during the spring and summer, providing water during months when much of California receives virtually no precipitation at all.
The water content of the snowpack on April 1 is the most important, but measurements at the end of January can give some indication of how things are going. California measures two ways. First, they conduct “media oriented” events in which they physically go to specific locations and measure the water content of the snowpack at that location. Last April 1 when they did this, there was no snow on the ground at all. This year, on February 2 there was a snow water equivalent of 25.4 inches, which is 130% of the average for that date.
Source: California Data Exchange Center 2016.
A second way they measure is via continuous electronic measurements at a couple of dozen locations around the state. Figure 1 at right shows the results for this year through February 12. The charts show the water content of the snowpack as percentages of the average amount on April 1. The top chart is for Northern California, the middle one is for Central California, and the bottom one is for Southern California. The blue line represents this year. The green line represents 1982-1983, the year with the biggest snowpack. The brown line shows 2014-2015, the year with the lowest snowpack on record. The light blue area represents average.
You can see that the average snow water content builds during the winter and reaches its maximum right around April 1 – that’s one reason the April 1 measurement is the most important. This year, in all 3 regions, the snowpack has built towards its April 1 average much better than it did last year. However, the data do not suggest that, statewide, it is an exceptional snow year. In this data, it looks like a pretty average snow year so far.
Somewhat worrying is the fact that since about February 1, the line for this year has leveled off. Might the snow season peter out and end up below average? I hope not.
Source: Mammoth Mountain Resort 2016.
Finally, I located one other source of data, this one more hopeful: the snow report at Mammoth Mountain, a large ski resort in the Central Sierra Nevadas. The resort tracks snowfall at the resort by year and by months, and it is available on the Web. Figure 2 shows total snowfall by year, and the different colors in the columns represent the amount for each month. The data suggest that at Mammoth Mountain it has been an above average snow year, 11th highest out of 47 years. February is, on average, the biggest snow month, however, and data for the first half of the month this year show the same tapering-off that the other data did (not shown on the chart).
I’m not sure how to reconcile these three contrasting data sources. Could above average snowfall have occurred, but above average temperatures melted more than usual, leaving about an average amount on the ground? Possibly, as January was 2.4°F warmer than average in California. That explanation would not, however, reconcile the difference between the electronic measurements and the media oriented measurement.
Now, one final word of caution: none of this changes my projection for California’s water future. It is surely good news that they are not having as dry a year as last year. However, my analysis was based on projected 30-year average precipitation levels. During any 30-year period, there are bound to be wetter years and drier years. If my analysis is correct, then while it is good news for right now, the real issue will be the average size of the snowpack over many years.
So, for the future, we’ll have to wait and see. For right now, it looks like a better snowpack year than last year: at least average, and perhaps above average.
In my next post, I will look at an analysis of water scarcity around the globe.
Sources:
California Data Exchange Center. 2016. California Statewide Water Conditions: Current Year Regional Snow Sensor Water Content Chart (PDF). Downloaded 2/13/16 from http://cdec.water.ca.gov/water_cond.html.
National Centers for Environmental Information. 2016. Climate at a Glance. Data retrieved 2/13/16 from http://www.ncdc.noaa.gov/cag/time-series/us.
Mammoth Mountain Resort. 2016. Extended Snow History. Data downloaded from http://www.mammothmountain.com/winter/mountain-information/mountain-information/snow-conditions-and-weather.
MoGreenStats 