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Disinfectant Byproducts Are the Most Common Water System Violations

In 2016, there were 2,733 public water supply systems in Missouri. In the previous post, I reported that 94.7% of the population received water from suppliers that had no violations of safe drinking water standards during the year (it has decreased from 95.7% in 2012). This means that 5.3% of the population was served by systems that did have a violation. As Missouri’s population in 2016 was 2,093,000, that means that almost 111,000 people were served water systems that had a violation during the year. This post looks into the nature of the violations.

In 2007 and 2010 there was an increase in the population affected by a violation. The cause in 2007 was an error in backwashing a filter at the Missouri American Water Company South Plant in St. Louis County. The error caused a spike in turbidity that lasted four minutes. During that time the water reached an estimated 24,578 customers, though no reports of illness were associated with this event. Even though only some customers were affected, federal documentation rules require that the entire service population be reported as exposed. In 2010, “the same phenomenon happened again.” (2012 Annual Compliance Report of Missouri Public Drinking Water, p. 4)

A violation does not indicate that public health was affected, but it creates the potential for a public health impact to occur. For this reason, violations are important administrative markers. The DNR monitors two broad kinds of violations. Water contaminants (chemicals and bacteria) can exceed their respective maximum concentration levels (health-based standards), or a water system can fail to meet adequate administrative standards (most often not performing and reporting the water quality tests required by law).

Figure 1 at right shows the percentage of the population served by community water systems that had different types of health-based violations in 2016. Violations of the Stage 1 & 2 DBP Rule were by far the most common, affecting about 3% of the population. (In the chart, Excel has rounded to the nearest full percent.) Figure 2 compares the data for 2013 and 2016.

(For larger view, click on figure.)

Figure 1. Data source: Missouri Department of Natural Resources, 2016.

Figure 2. Data source: Missouri Department of Natural Resources, 2016.

 

 

 

 

 

 

 

 

 

 

In previous years, the most common type of violation had to due with coliform bacteria. The text of the report indicates that in 2016 coliform contamination continued to represent the most common kind of violation. However, as shown in Figures 1 and 2, violations of the Stage 1 & 2 DBP Rule affected more of the population than did coliform contamination. Let me explain what this means.

Coliform bacteria are a family of bacteria that live naturally in the soil, and which also live naturally in the guts of many animals, including humans. Consequently, it is not uncommon for some coliform bacteria to get into water supplies. Most coliform bacteria are safe, but a few species of coliform bacteria (including some E. coli) can cause illness in humans. In addition, because they live in great numbers in the guts of humans and animals, their presence in large numbers serves as a sign of fecal contamination. Human and animal feces contain many species of harmful bacteria, and the presence of too many coliform bacteria serves as a marker that these other bacteria might be present, too.

Over the years, the EPA has lowered the maximum allowable level of coliform bacteria concentration in drinking water, and water systems have had to increase their treatment of the water to kill the bacteria. The treatment usually occurs in stages. Unfortunately water often contains organic matter, such as algae or dissolved plant material. If the water treatment is not done properly, the chemicals used to kill the bacteria react with the contaminants to form byproducts that can also be harmful. The Stage 1 & 2 DBP (Disinfectants and Disinfection ByProducts) Rule requires water systems to monitor the level of such byproducts in their water. Thus, it may be because water systems are using additional treatment to kill bacteria that decreasing coliform contamination and increasing violations of the Stage 1 & 2 DBP rule are occurring.

The presence of E. Coli or of other species of coliform bacteria remains the most serious violation, in the Department’s opinion. Thus, the presence of either results in a boil order. All water systems in Missouri are required to test for E. Coli. Nineteen systems received boil orders in 2016. That number has been moving mostly sideways since 2012, but represents a decrease from 32 in 2011. Most lasted for a few days up to two weeks, but some lasted for several months.

Seventy-four systems had chemical violations, almost all for trihalomethanes . Trihalomethanes are water treatment byproducts. They form if disinfectants used to treat the water (chlorine or bromine) react with matter that may be present in the water (e.g. decaying vegetation).

Eleven systems had violations involving excess radiological contaminants (down from 14 systems in 2012 and 16 systems in 2011). The problems came from several radiological elements, see the report for full details.

In 2016, 7 water systems had Surface Water Rule violations, the same as in 2013. All of the violations were for combined filter effluent turbidity. Systems must filter surface water to remove cryptosporidium, a parasite that causes diarrhea, and a violation of the turbidity rule means the filtering may not be adequate to remove the parasite.

As noted above, some of violations can be quite brief, and the threat they represent to public health can be small. However, the DNR puts a special focus on water systems that repeatedly fail to meet monitoring standards, and on those with a routine sample that tests positive for coliform, but which fail to submit follow-up or repeat samples as required.

As reported in the previous post, 38 water systems were listed as having had three or more major monitoring violations in 2016 (up from 27 systems in 2013). Many of them were in violation for many months. Figure 3 shows the list. Only 6 water systems had water that tested positive for excess coliform bacteria, but failed to provide the required follow-up samples for testing. This represents a decrease from 47 systems in 2013. Figure 4 shows the list.

Figure 3. Source: Missouri Department of Natural Resources, 2016.

Figure 4. Source: Missouri Department of Natural Resources, 2016.

 

 

 

 

 

 

 

 

 

 

 

 

Sources:

Missouri Department of Natural Resources. 2013 Annual Compliance Report of Missouri Public Drinking Water Systems. https://dnr.mo.gov/env/wpp/fyreports/index.html. Published 2014-11-18.

Missouri Department of Natural Resources. 2016. Annual Compliance Report of Missouri Public Water Systems. Downloaded 5/11/2018 from https://dnr.mo.gov/env/wpp/fyreports/index.html.
Missouri Census Data Center. Population Estimates for Missouri. Viewed online 6/28/2018 at http://mcdc.missouri.edu/trends/estimates.shtml.
Wikipedia contributors. (2018, May 15). Trihalomethane. In Wikipedia, The Free Encyclopedia. Retrieved 22:26, July 5, 2018, from https://en.wikipedia.org/w/index.php?title=Trihalomethane&oldid=841446641

Most Public Water Systems Met All Health-Based Regulations in 2016

The previous post reported that the Census of Missouri Public Water Systems – 2016 found 2,733 public water systems in Missouri, of which 2,720 were active. This post looks at Missouri’s 2016 Annual Compliance Report of Missouri Public Drinking Water Systems. It is the most recent summary report on Missouri’s public water systems. Additional detail about specific systems can be found in reports published by the systems themselves.

A public water system is one that provides water to at least 15 service connections, or to an average of at least 25 people for at least 60 days each year. Community Systems (CWS) supply water to the same population year-round. Non-Transient Non-Community Water Systems (NTNCWS) supply water to at least 25 of the same people at least 6 months per year, but not year-round. An example might be a school that has its own water system. Transient Non-Community Water Systems (TNCWS) provide water in places where people do not remain for long periods of time. Examples might include gas stations or campgrounds that have their own water systems.

The amount of treatment that water must receive differs depending on the source of the water. Surface water and underground water under the direct influence of surface water are more vulnerable to contamination, so they receive more treatment. Underground water from aquifers not under the direct influence of surface water tend to contain water that is heavily filtered by the rock through which it seeps. Sometimes, the seepage is so slow that the water is old, predating most forms of modern contamination.

Figure 1. Source: Missouri Department of Natural Resources, 2016.

Figure 2. Source: Missouri Department of Natural Resources, 2016.

 

 

 

 

 

 

 

 

Figure 1 shows the percentage of population served by community water systems that meet all health-based requirements by year. Figure 2 shows the number of violations involving E. Coli or acute contamination levels. Non-compliance can result from many factors from broken pipes, to human error, to systems that are inadequate in the first place. The EPA goal is for 95% of the public water systems in a state to have no health-based violations in a year. In 2016, Missouri had 94.7% compliance. That is close to the goal, but it is a decrease from over 95% in 2013. The chart shows no general trend, but in some years the compliance rate appears to slip significantly. The last 3 years have all been below the EPA goal.

The number of violations for E. coli and acute MCL violations (maximum contaminant level violations – also mostly due to coliform contamination) peaked in 2008 and had another bad year is 2011. Since 2012, it has mostly been moving sideways. In 2016, there were 19 violations.

Ninety-four-point-seven percent is a high mark – you would have been happy to score 94.7% on tests at school, wouldn’t you? Since Missouri’s population in 2016 was 2,093,000, however, it means that water systems serving almost 111,000 people had a health-based violation. (Missouri Census Data Center)

In 2016, 38 public water systems had 3 or more “major monitoring violations” of the rules to protect against coliform contamination. That is an increase from 27 in 2013. Monitoring violations are a concern because hinders the Department of Natural Resources’s ability to determine if the drinking water is safe, especially if the monitoring violation occurs multiple times.

In 2016, however, there were only 6 major “repeat monitoring violations,” down from 41 in 2013. A repeat monitoring violation occurs when If a routine sample from a public water system tests positive for coliform bacteria, then the system is required to submit a second test to confirm the finding, and to conduct follow up testing to ensure that the problem is eliminated. A repeat monitoring violation occurs when the system fails to submit the repeat testing or follow up testing.

None of these violatios mean that people were actually sickened, the report does not address that issue. It does mean, however, that a potential vulnerability occurred, and that continuing work needs to be done to ensure that Missourians have safe drinking water.

The next post will look into the nature of the violations that occurred.

Sources:

Missouri Census Data Center. Population Estimates for Missouri. Viewed online 6/28/2018 at http://mcdc.missouri.edu/trends/estimates.shtml.

Missouri Department of Natural Resources. 2016. Annual Compliance Report of Missouri Public Water Systems. Downloaded 5/11/2018 from https://dnr.mo.gov/env/wpp/fyreports/index.html.

Say Goodby to Saline Lakes


“Many of the world’s saline lakes are shrinking at alarming rates, reducing waterbird habitat and economic benefits while threatening human health.”


So begins a recent report in Nature Geoscience.

Figure 1. Major Saline Lakes Across the World. Source: Wurtsbaugh et al, 2017.

Saline lakes, also known as salt lakes, are landlocked bodies of water with a concentration of dissolved minerals several times higher than in freshwater lakes, sometimes even higher than in the ocean. The largest in the world is the Caspian Sea, but other well known saline lakes include the Dead Sea and the Great Salt Lake. Two dozen of the world’s most important saline lakes are shown in Figure 1. The larger blue dots indicate those that formerly had a surface area larger than 250 square kilometers (larger than a circular lake about 18 miles across).

Wayne Wurtsbaugh and his associates looked at the volume of water in 6 saline lakes. The sample is loaded towards the United States, but includes two in Central Asia:

  • The Aral Sea (Kazakhstan and Uzbekistan)
  • The Dead Sea (Israel,  Jordan, and Palestine)
  • The Great Salt Lake (Utah, United States)
  • Lake Urmia (Iran)
  • Owens Lake (California, United States)
  • Walker Lake (Nevada, United States)

Figure 2. Percent Decline in Volume of 6 Saline Lakes. Source: Wurtsbaugh et al, 2017.

Figure 2 shows the loss of water in the 6 lakes over time, with some lakes going back to 1875. Every one of them has experienced a dramatic loss.

The Dead Sea has experienced the lowest percentage loss, the reason being that it is a very deep lake (Maximum depth 978 ft.) Despite that fact, the surface of the lake has dropped 28 feet, and it has been divided in two. (Wikipedia 2018b, Wurtsbaugh et al, 2017).

Starting in 1913, the streams that fed Owens Lake in California were diverted to provide water to Los Angeles. (See my post on California’s water supply, here. For movie buffs, this is also the subject of the famous movie Chinatown.) The lake has been almost completely drained, and is now mostly a dry lake (salt flat). (Wikipedia 2018c)

Figure 2. The Aral Sea in 2014. Source: NASA 2014.

Perhaps the “poster child” for what can happen to dry lakes is the Aral Sea. Formerly one of the largest lakes in the world, with a surface area of 26,300 square miles (almost the size of Lake Superior), water diversion has turned it into several small lakes, plus a whole lot of dry lake bed (salt flat). Figure 2 shows the Aral Sea in 2014, with the gray line showing the former extent of the lake. (Micklin 2007, Wikipedia 2018a, NASA 2014)

The demise of these lakes has not been caused primarily by a decline in precipitation, but rather by diversion of water for human consumption. In some cases, the consumption has been to provide potable water for large population, as in the case with Owens Lake and Los Angeles. In other cases, it has been to provide irrigation water for crops, as in the case with the Aral Sea.

Many aquatic species live in saline lakes, and the lake’s demise obviously devastates them. In addition, the survival of many species of migratory birds depends on an unbroken chain of places they can stop and refuel on their long journeys. Break the chain in even one place, and their survival is threatened. Saline lakes are one of the places birds stop during migration, and draining the lakes threatens to break the chain.

In addition, when saline lakes are emptied, what remains behind is a fine, salty dust that is laced with heavy metals and pesticide residue that drained into the lake over many years. It is picked up by the wind and blown for miles. Posts in this blog have discussed the health threats represented by airborne particulates, and the damage done by this salty dust has been well documented around the Aral Sea. Aerial photographs revealed salt plumes extending as much as 500 km. (310 miles) from the lake. It is considered an essential factor in the region’s high incidence of both acute and chronic illness. (Micklin 2007)

Of these lakes, the 2 with the highest percentage of remaining water are the Dead Sea and the Great Salt Lake. Wurtsburgh et al conclude that the key to conserving these lakes is to provide the river inflow needed to restore and sustain them. Otherwise, these once important lakes will remain (become) nothing but a choking dust in the wind.

Sources:

Micklin, Philip. 2007. The Aral Sea Disaster. Annual Review of Earth and Planetary Sciences. 35:47-72. Available online at http://www.annualreviews.org/action/doSearch?SeriesKey=earth&AllField=Micklin&startPage=&ContribAuthorStored=Micklin%2C%20Philip.NASA. 2014.

NASA. 2014. ”The Aral Sea Loses Its Eastern Lobe.” Earth Observatory. Downloaded 2018-01-04 from https://earthobservatory.nasa.gov/IOTD/view.php?id=84437.

Wikipedia. 2018a. “Aral Sea.” Wikipedia. Viewed online 2018-01-04 at https://en.wikipedia.org/wiki/Aral_Sea.

Wikipedia. 2018b. “Dead Sea.” Wikipedia. Viewed online 2018-01-04 at https://en.wikipedia.org/wiki/Dead_Sea.

Wikiepedia. 2018c. “Owens Lake.” Wikipedia. Viewed online 2018-01-04 at https://en.wikipedia.org/wiki/Owens_Lake.

Wurtsbaugh, Wayne, Craig Miller, Sarah Null, Justin DeRose, Peter Wilcock, Maura Hahnenberger, Frank Howe, and Johnnie Moore. 2017. Nature Geoscience, Vol 10. DOI: 10.1038/NGEO3052. Available online at www.nature.com/naturegeoscience.

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.

Missouri Fish Advisory for 2017

Table 1. Source: Missouri Department of Health and Senior Services, 2017.

Eating fish is thought to have healthful benefits, including cognitive benefits for the young and a reduction in the risk of cardiovascular disease in adults. However, environmental toxins limit the amount of fish you should eat. The principle of bioaccumulation, which explains why, was reviewed in the previous post.

Whether fish are safe to eat depends on the water where they were caught. The Missouri Department of Health and Senior Services publishes a report identifying lakes, rivers, and streams where environmental contamination requires a fish advisory. This post looks at the report for 2017.

Table 1 lists the bodies of water for which fish advisories have been issued, the species of fish affected, the sizes of fish affected, the contaminants, and the limit that should be observed (serving advice).

Looking at the table, the toxins include chlordane, lead, mercury, and PCBs. In some cases the fish are safe to eat once weekly, in other cases only once monthly, and in some cases they should not be eaten at all. Several species from rivers near Missouri’s old lead belt tend not to be safe at all. I’ve posted on the Big River previously (here).

The advisories are separated into those that apply to all consumers, and those that apply to “sensitive populations.” Please look at who is included under “sensitive populations”: children younger than 13 and women who are either pregnant, nursing, or of childbearing age. Wow, that is a huge portion of the population! For them, there is no fish caught in any body of water in the United States that is safe to consume more than once weekly. And for them, several important species of game fish caught in Missouri waters should only be consumed once monthly.

Figure 1. Source: Missouri Department of Health and Senior Services.

Figure 1 shows a map of the affected bodies of water. Looking at the bodies of water affected, you can see that they cover a lot of territory: the entire lengths of the Mississippi and Missouri Rivers in the state, the major portion of the Big River, the Blue River, Clearwater Lake (ironic, no?), and Montrose Lake.

The contaminants of concern listed by the Missouri report include chlordane, PCBs (polychlorinated biphenyls), lead, and methylmercury. Chlordane was an insecticide. It was widely used as a termite control in residences, and it was used widely on crops. Starting in 1988, sales of chlordane were banned in the United States. However, chlordane persists in the environment. It adheres to soil particles in the ground and very slowly dissolves into groundwater, where it migrates to rivers and lakes. Once in the water of rivers and lakes, it bioaccumulates. That is why, even though banned in 1988, it is still a contaminant of concern in Missouri fish. Elevated levels of chlordane in the blood are associated with an increased risk of cognitive decline, prostate cancer, type-2 diabetes, and obesity. According to the Missouri report, levels of chlordane are gradually decreasing, but remain a concern in some bodies of water.

PCBs are a family of chemicals that were once widely used as insulating and cooling liquids in electrical mechanisms. PCBs were banned in the United States in 1979, however they are extremely long-lived compounds, and it is estimated that 40% of all PCB ever manufactured remain in use. Toxicity varies among specific chemicals in the family. Exposure to PCBs is capable of causing a variety of health effects, including rashes, reduced immune function, poor cognitive development in children, liver damage, and increased risk of cancer. PCBs in the environment generally enter bodies of water, where they enter the bodies of aquatic species and bioaccumulate up the food chain. According to the Missouri report, levels of PCB are gradually decreasing, but remain a concern in some bodies of water.

Lead is a heavy metal that was once heavily mined in Missouri. Lead mining continues, and as recently as 2014, more lead was released into the environment in Missouri than any other toxic chemical. (See here.) Lead used to be released into the environment through the inclusion of tetraethyl lead in gasoline, and through lead paint. Both of those uses have been banned in the United States. Today, lead enters the environment through mine tailings. Thus, it is of greatest concern in locations that either have or had significant lead mining activities (portions of Southeastern Missouri, for instance). Tailings containing lead were (are) dumped on the ground. From the tailings lead washes into nearby bodies of water, where it is ingested by aquatic species and then bioaccumulates. Lead is readily absorbed by living tissue. It affects almost every organ and system in the body. At high levels it can be immediately dangerous to life and health. At lower levels, symptoms include abdominal pain, weakness in fingers, wrists, and ankles, blood pressure increases, miscarriage, delayed puberty, and cognitive impairment.

Mercury enters the environment from many sources. One important source is coal. When coal is burned, it is emitted up the flue. Though the amount in any lump of coal is tiny, so much coal is burned to produce energy that tons and tons are emitted every year. The mercury falls out of the atmosphere, where it gets washed into bodies of water. There, it is converted by microbes into methylmercury, which is then ingested into aquatic species, and it bioaccumulates. In children a high level of methylmercury has been associated with language and memory deficits, reduced IQ, and learning disabilities. In adults, it has been associated with an increased risk of cardiovascular disease and autoimmune conditions.

It seems to me that for all of these contaminants, the situation may be slowly improving, though it is still problematic. The persistence of these contaminants in the environment, in many cases decades after their manufacture was banned, demonstrates an important environmental principle: the environmental problems you create may not go away quickly. They are likely to remain with you for a long, long time.

Sources:

Missouri Department of Health and Senior Services. 2017. 2017 Missouri Fish Advisory: A Guide to Eating Missouri Fish. Downloaded 3/9/17 from http://www.health.mo.gov/fishadvisory.

Wikipedia. Chlordane. Viewed online 3/15/2017 at https://en.wikipedia.org/wiki/Chlordane.

Wikipedia. Lead. Viewed online 3/15/2017 at https://en.wikipedia.org/wiki/Lead.

Wikipedia. Methylmercury. Viewed online 3/15/2017 at https://en.wikipedia.org/wiki/Methylmercury.

Wikipedia. Polychlorinated biphenyl. Viewed online 3/15/2017 at https://en.wikipedia.org/wiki/Polychlorinated_biphenyl.

Environmental Toxins Limit Fish Consumption

Eating fish may be good for you, or it may poison you. (Pick one)

In the 1970s, researchers reported that native people living in Greenland (Inuits) had very low rates of heart disease compared with counterparts living in Denmark. Scientists attributed these health benefits to the consumption of fish and sea mammals containing high levels of long-chain polyunsaturated fatty acids. Recently, however, research has questioned the accuracy of these early studies, as more recent research shows that the rate of heart disease and heart attack among the Inuit are similar to those in non-Inuit populations. Thus, there has been some question regarding how strong the association is between reduced risk of cardiovascular disease and fish consumption. The situation reminds me of one of my favorite sayings: It ain’t what we don’t know that’s gonna hurt us, it’s what we do know that just ain’t so.

Over the years, thousands of research studies have been conducted, with the result that the consumption of fish is included in most dietary guidelines. The benefits are primarily considered to be the previously mentioned reduction in the risk of coronary heart disease in adults, but also an improvement in cognitive development in infants and young children.

The current dietary guidelines in the USA have moved away from the concept of the minimum daily requirement. Instead they describe recommended patterns of healthy eating. The recommendation for seafood has not changed, however: 8 oz. of seafood per week. (Dietary Guidelines, p. 18)

It is generally recognized, however, that some fish species contain significant levels of contaminants. These contaminants include a number of really nasty poisons, including chlordane, polychlorinated biphenyls (PCBs), lead, and methylmercury. These compounds can be toxic even in very small amounts, and they are bioaccumlative.

Bioaccumulation is an important concept in understanding environmental toxins. The basic idea is that even tiny amounts of toxin can build up in the body. Here’s how: at any given feeding, a toxin may be eaten in such tiny amounts that there is no immediate effect on the animal that consumes it. However, it is absorbed by the body, and it is not readily eliminated by natural processes. Thus, over time, the amount in the body builds up each time the animal eats a little more.

Imagine a lake. Mercury emitted by coal-burning power plants falls into the lake, where microbes convert it to methylmercury. Algae living in the lake take in some of that methylmercury. Along comes a tiny fish fry, and it eats some of that algae. Now with each mouthful of algae, the fish fry ingests a dose of methylmercury. And it starts to build up. How many mouthfuls of algae does a fish fry eat? I don’t know, but it is quite a lot. Now, along comes a medium-sized fish, and it eats the fish fry. With one bite, it has ingested not just a tiny amount of methylmercury, but all the methylmercury that built up in the body of the fish fry during its lifetime. How many fish fry does a medium-sized fish eat? I don’t know, but it is quite a few, and the medium-sized fish ingests all of the methylmercury built up in the bodies of each fish it eats. Now, along comes a large fish, and it eats the medium-sized fish. With one bite, it has ingested not just a tiny amount of mercury, but all the methylmercury built up in the body of the medium-sized fish. How many medium-sized fish does a large fish eat? I don’t know, but it is quite a few, and the large fish ingests all of the methylmercury built up in the bodies of each fish it eats.

Now, let’s imagine that our fish are living in a Missouri lake. Along comes a fisherman, and he catches one fish per week and eats it. That will be 52 fish per year. Now, I don’t know what the actual numbers are, but let us assume that a fish fry eats 1,000 individual alga, while a medium-sized fish eats 100 fry, and a large fish eats 100 medium-sized fish. These estimates may be wildly wrong, but the point is to illustrate the principle of bioaccumulation, and they will allow us to do so.

Using the estimates above, each fish fry will ingest the methlymercury contained in 1,000 algae; each medium-sized fish will ingest the amount contained in 100,000 algae; each large fish will ingest the amount contained in 10 million algae, and in a year, our fisherman will ingest the amount contained in 520 million algae. If he continues for 10 years, he will consume the amount contained in 5.2 billion algae.

Over time, the amount of methylmercury in our fisherman’s body will build up, perhaps eventually reaching the point where it starts to poison him.

Now, my presentation is over-simplified; in real life bioaccumulation is much more complex. Further, the numbers I chose for my progression were totally arbitrary. Nonetheless, they illustrate the basic idea of bioaccumulation. And the principle applies not only to methylmercury, but also to lead, PCBs, and dioxins.

The result is that, however good for you eating fish may be in theory, there are limits due to environmental contaminants. The next post will look at what those limits are in Missouri.

Sources:

Committee on a Framework for Assessing the Health, Environmental, and Social Effects of the Food System; Food and Nutrition Board; Board on Agriculture and Natural Resources; Institute of Medicine; National Research Council; Nesheim MC, Oria M, Yih PT, editors. A Framework for Assessing Effects of the Food System. Washington (DC): National Academies Press (US); 2015 Jun 17. ANNEX 1, DIETARY RECOMMENDATIONS FOR FISH CONSUMPTION. Available from: https://www.ncbi.nlm.nih.gov/books/NBK305180.

Missouri Department of Health and Senior Services. 2017. 2017 Missouri Fish Advisory: A Guide to Eating Missouri Fish. Downloaded 3/9/17 from www.health.mo.gov/fishadvisory.

U.S. Department of Health and Human Services and U.S. Department of Agriculture.
2015–2020 Dietary Guidelines for Americans. 8th Edition. December 2015. Available at http://health.gov/dietaryguidelines/2015/guidelines.

Harmful Algal Blooms

Figure 1. Algal Bloom Covers A Lake. Photo Source: Zwerneman 2014.

Figure 1. Algal Bloom Covers A Lake. Photo Source: Zwerneman 2014.

In 2014 and 2015 toxic algal blooms on Lake Erie caused the City of Toledo to warn residents not to drink the city’s public water. This algal bloom has become a more-or-less annual event.

In 2015, a plume of algae spread along the Ohio River, covering 636 miles, about 2/3 of the entire river, from Wheeling WV, to Cannelton IN. For more than a month it curbed boating, caused problems for water utilities, and drove swimmers out of the water.

This year (so far, at least) the headlines were grabbed by a toxic algal bloom in Florida. The green slime originated in Lake Okeechobee, then spread via rivers to the Fort Meyers area on the west, and especially to the Stewart area on the east. States of emergency were declared in Martin, Lee, St. Lucie, and Palm Beach Counties.

These are all examples of Harmful Algal Blooms, or HABs. What’s going on, and how has Missouri been affected?

(Click on graphics for larger view.)

Algal blooms are caused by microorganisms. They occur naturally in all water, and are only absent if you purify and treat the water. Even in purified water, as every swimming pool or aquarium owner knows, they will multiply and slime your water if you don’t give the water constant vigilance.

The most common of the microorganisms is often called blue-green algae. Despite its common name, it is not algae at all, but a phylum of bacteria, called cyanobacteria. Most species of it are harmless, but some species are toxic. Sometimes conditions conspire to cause these bacteria to multiply explosively, causing what we call an algal bloom. These blooms sometimes contain significant numbers of toxic microorganisms, which make drinking the water, or even swimming in it, hazardous. The most common of these is a genus called microcystis. For some reason HABs are increasing in frequency.

In most cases, casual contact with the water causes mild reactions like rashes. Drinking it, however, can cause liver damage, and can even be fatal. They are harmful to wildlife as well as humans, and can cause large fish kills.

Many of the HABs occur along our nation’s seacoasts. Missouri is an inland state, however, so for the rest of this post I will concern myself only with algal blooms on freshwater systems. HABs are a relatively recent subject of study, so nobody knows how often they have occurred and where. Similarly, in a state like Missouri, many of them occur in relatively small bodies of water that may not be monitored. Thus, the blooms may go undetected.

Figure 2. Source: Lopez et al, 2008.

Figure 2. Source: Lopez et al, 2008.

HABs causing significant large-scale disruption have not yet been reported in Missouri, but as Figure 2 shows, they have been reported in many of our neighboring states. There is no reason to believe that Missouri is immune.

In 2007, the United States Geological Survey completed a study looking for the presence of toxic species of cyanobacteria and for the toxins they produce in the nation’s lakes and reservoirs. They found that:

  • Cyanobacteria are ubiquitous, occurring in 98% of the samples they collected;
  • One or more toxic species of cyanobacteria were present in 67-95% of the waters samples collected;
  • Toxins were present in only 4.0-7.7% of samples, depending on the toxin. Thus, the presence of algae, and even of toxic species of algae, does not necessarily mean that the water is unsafe. Only when a bloom causes the number of toxic cyanobacteria to increase does the situation become problematic.

Figures 3, 4, and 5 show the sites tested, and the locations of sites where the cyanobacteria toxins were found. Figure 3 shows Cylindrospermopsin, Figure 4 shows Saxitoxin, and Figure 5 shows Microcystin. The color codes for the concentration: clear means none detected, blue means detected at low concentrations, yellow means detected at moderate concentrations, and red means detected at high concentrations. Microcystin and Cylindrospermopsin were detected in Missouri, the latter at a high concentration.

Figure 3. Source: USGS 2016a.

Figure 3. Source: USGS 2016a.

Figure 3. Source: USGS 2016a.

Figure 4. Source: USGS 2016a.

Figure 4. Source: USGS 2016a.

Figure 5. Source: USGS 2016a.

 

 

 

 

 

 

(Click on graphics for larger view.)

Photo by John May, 2016.

Figure 6. Photo by John May, 2016.

Some of this should not be surprising. I suspect that any of us who have spent time near bodies of water in Missouri have seen algae on them. Indeed, Figure 6 shows an algal bloom occurring on a lagoon in Forest Park in St. Louis on the day I wrote this article (7/21/16). The light green material in the water is the algae.

Missouri tests lakes for the concentration of chlorophyll-a, but not streams. Chlorophyll-a is a green pigment associated with organisms that do photosynthesis. It is present in cyanobacteria, and the assumption is that chlorophyll-a levels indicate the amount of cyanobacteria in the water. In 2014, excess levels of chlorophyll-a impaired more acres of Missouri lakes than any other cause. Lakes in all regions of Missouri are showing increasing trends in chlorophyll-a levels, with trends in the Glaciated Plains and Osage Plains regions being statistically significant.

While a useful water quality standard, the reported concentration of chlorophyll-a only represents the level at the time testing occurred. It cannot be translated into the presence or absence of an algal bloom at other times during the year. Further, the USGS assessment found that chlorophyll-a is not a reliable indicator of the presence of algal toxins. Neither algal counts nor algal toxins are tested in Missouri’s surface water or in Missouri’s drinking water. The Department of Conservation encourages the reporting of fish kills in the state, but there is no system for reporting or tabulating algal blooms.

Phosphorus appears to be the factor that most limits algal growth in Missouri’s lakes. Where algae has access to phosphorus, it grows more vigorously. Phosphorus is a pollutant that flows into Missouri’s lakes from some industrial or urban sources, but it is especially an agricultural chemical that runs off from fertilized farms.

Much of Missouri’s population draws its drinking water from the Missouri and Mississippi Rivers. Iowa, Illinois, Kansas, Minnesota, Nebraska, and Wisconsin are among the nation’s most intensively farmed states, and Missouri is downstream from all of them. Could our two rivers experience HABs as did Lake Erie and the Ohio River? Could HABs make our water undrinkable? For how long?

Is there a reason to think that Missouri should be immune from such problems? I don’t know of one. So far we have dodged the bullet. When or how a seriously disruptive HAB might occur in Missouri is anybody’s guess.

Sources:

Dewey, Eliza. “Where Will the Green Slime Go? Florida Tracks Spreading Algae.” The Miami Herald. 7/7/2016. Viewed online 7/21/16 at http://www.miamiherald.com/news/local/environment/article88302462.html.

Lakes of Missouri Volunteer Program. Blue Green Algae in Missouri. Downloaded 7/21/16 from http://lmvp.org/bluegreen.

Lopez, C.B., Jewett, E.B., Dortch, Q., Walton, B.T., Hudnell, H.K. 2008. Scientific Assessment of Freshwater Harmful Algal Blooms. Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health of the Joint Subcommittee on Ocean Science and Technology. Washington, DC. https://www.whitehouse.gov/sites/default/files/microsites/ostp/frshh2o0708.pdf.

Missouri Department of Natural Resources. 2015. Missouri Integrated Water Quality Report and Section 303(d) List, 2014. Downloaded 4/20/2016 from http://dnr.mo.gov/env/wpp/waterquality/303d/303d.htm.

Neuhaus, Les. “Miles of Algae and a Multitude of Hazards.” The New York Times. 7/18/2016. Viewed online 7/21/16 at http://www.nytimes.com/2016/07/19/science/algae-blooms-beaches.html.

United States Geological Survey. 2016a. New Science Challenges Old Assumptions about Harmful Algal Blooms. Viewed online at https://www.usgs.gov/news/new-science-challenges-old-assumptions-about-harmful-algal-blooms.

United States Geological Survery. 2016b. New Study on Cyanotoxins in Lakes and Reservoirs Provides Insights into Assessing Health Risks. Viewed online 7/22/2016 at http://toxics.usgs.gov/highlights/2016-05-31-cyanotoxins_in_lakes.html.

Wines, Michael. “Toxic Algae Outbrteak Overwhelms a Polluted Ohio River.” The New York Times. 9/30/2015. Viewed online 7/22/16 at http://www.nytimes.com/2015/10/01/us/toxic-algae-outbreak-overwhelms-a-polluted-ohio-river.html.

Zwerneman, Annie. 2014. Monitoring Harmful Algal Blooms? There’s an App for That! The EPA Blog, 7/17/14. Downloaded 7/22/16 from https://blog.epa.gov/blog/tag/usgs.

Yearly Variation in Missouri River Flow Increasing

In the previous post I looked at average flow on the Missouri River over time at two locations: Kansas City and Hermann. Streamflow at Hermann is larger than at Kansas City, as would be expected. Streamflow at both locations seems to be gradually trending higher, and the variation in streamflow between years is large.

Figure 1. Data sources: United States Geological Survey, National Centers for Environmental Information.

Figure 1. Data sources: United States Geological Survey, National Centers for Environmental Information.

Figure 1 is reproduced from the previous post. It shows average streamflow by year as measured at Kansas City (in blue) and Hermann (in red). These lines should be read against the scale on the left vertical axis. The chart also shows yearly precipitation in the Northern Rockies & Plains, the climate region that approximates the drainage basin of the Upper Missouri River, and it should be read against the axis on the right. I had Excel calculate linear regression trend lines for all three, and they are shown as dashed lines.

One might expect that precipitation in the Missouri River drainage basin is the most important factor impacting river flow. One might also expect that precipitation early in the year (winter and spring snowfall and summer rain) are more important than fall rain, giving the water time to run off into the river. Thus, the precipitation would affect the river most during the year it fell. If these two hypotheses are correct, then one would expect there to be a moderately large correlation between yearly precipitation and annual average water flow. Indeed, if one compares the shape of the green line to the other two, you can see that, though the relationship is not perfect, they do tend to follow each other, especially during later years. For instance, they all have a low valley in 1988, a high peak in 1993 (the year of the Great Flood), a valley in 2002, and a peak in 2010-11.

The statistical technique used to determine if values of one data series are related to those of another is called correlation. Correlation values run from -1.0 to +1.0. A value of 0.0 means there is no relation at all. A value of -1.0 means there is a perfect relation, but it is inverse – one data series has low values when the other has high, and vice-versa. A correlation of +1.0 means there is a perfect relation, and it is direct – when one data series is high, the other one is too, and when one is low, so is the other. The correlation between rainfall in the Northern Rockies & Plains and Missouri River discharge at Kansas City is 0.53. That is a moderate direct correlation, meaning that precipitation plays a major role in determining Missouri River flow at Kansas City, but by no means the only role.

Figure 2. Data sources: United States Geological Survey, National Centers for Environmental Information.

Figure 2. Data sources: United States Geological Survey, National Centers for Environmental Information.

Just looking at the data, it appears that annual variation in the flow of the Missouri River has increased over time. This seems counterintuitive, as one would expect that completion of the dam system, plus increased experience in operating it, would lead to a smoothing of the yearly variation. To check more carefully, I computed a chart showing the average variation between years by decade (Figure 2). As before, the blue line represents Missouri River flow at Kansas City, the red line at Hermann, and these should be read on the left axis. The green line represents annual variation in precipitation in the Northern Rockies & Plains, and should be read on the right axis. As in Figure 1, I had Excel compute trendlines for all three, and they are shown as dashed lines.

First, variation is larger at Hermann than at Kansas City. This should be expected for two reasons. First, the flow at Hermann is larger than at Kansas City, and thus, the magnitude of the variation should be, also. Second, Hermann experiences the influence of several unregulated Missouri tributaries (e.g. the Gasconade and the Grand), while Kansas City is more completely influenced by the release of water from upstream reservoirs.

Second, at both locations, the size of the annual variation has increased over time. While the individual data points bounce around a bit, the trendlines are very similar.

Third, the annual variation in rainfall has also increased over time. In fact, the pattern of variation in rainfall is very similar to the pattern in variation in river flow at Kansas City: the shape of the two lines is almost identical.

I conclude that rainfall in the Northern Rockies and Plains is probably the largest and most important factor impacting Missouri River flow, but the effect may not all occur during the year in which the precipitation fell. It may be spread among two or more years. Other factors may impact river flow in any given year.

Increasing variability is also probably a problem for managers of the river. Precipitation is gradually increasing over time, and so is streamflow. Add increased variation to the equation, and you have the potential for increased flooding. At the same time, the fact that the all-time low flow year was 2006 (see previous post) suggests that the trend towards increased flow has not eliminated the potential for problems with low water flow.

One must use caution interpreting this data, particularly since construction of the dams and reservoirs along the Missouri overlapped the start of the data series. I don’t know how dam and reservoir construction impacted this data. With that said, the data seem to suggest a trend toward increased precipitation in the Northern Rockies and Plains, resulting in a trend toward increased annual flow in the Missouri River at both Kansas City and Hermann, and increased variation in the flow from year-to-year.

Sources:

For river flow: United States Geological Service. National Water Information System: Web Interface. USGS Surface-Water Annual Statistics for Missouri. This is a data portal. Working your way through this data portal is tricky and complex. The sites used above are sites 06893000 (Kansas City) and 06934500 (Hermann). The parameter used was Discharge (sometimes called streamflow) in cubic feet per second. The dates used were 1958-2015. Data was downloaded 6/8/16, and the starting point for the data portal was at http://waterdata.usgs.gov/mo/nwis/annual/?referred_module=sw.

For precipitation: National Centers for Environmental Information. Climate at a Glace. This is a data portal. I selected Parameter: Precipitation, Time Scale: Year-to-Date, Month: Annual, Start Year: 1958, End Year: 2015, State/Region: Northern Rockies and Plains, and Climate Division/City: Entire Region. Data downloaded 7/9/16 from http://www.ncdc.noaa.gov/cag/time-series/us.

Missouri River Annual Flow 2016

The last time I looked at water flow on the Missouri River was 2013; it’s time for an update.

Water flow on the Missouri is an important question. Floods on the river have cost untold millions of dollars of damage over the years, it is the source of drinking water for more than half of Missouri’s population, including the cities of St. Joseph, Kansas City, Columbia, and St. Louis, it is used for irrigation, and it is used as a an artery for the shipment of food and other commodities.

Figure 1. Source: Google Earth.

Figure 1. Dams Along the Missouri River. Source: Google Earth.

Missouri is downstream from 15 dams on the mainstem of the Missouri River, and more on tributary rivers. One of the most important functions of these dams is to regulate the flow of the river, holding back water during times of flood and releasing reserved water during times of drought. As you go up river, the most important dams are the Gavins Point Dam (1957), the Fort Randall Dam (1956), the Big Bend Dam (1966), the Oahe Dam (1962), the Garrison Dam (1953), the Fort Peck Dam (1940), and the Canyon Ferry Dam (1954). All but Gavins Point impound more than a million acre-feet of water.

The flow of the river is so important that conflict has arisen between upstream states, which want enough water conserved in their reservoirs for drinking and farming, and downstream states, which want enough water released to keep navigation systems open. Throw into this mix the environmentalists, who want to return the river to its natural state as much as possible to support important species and the riverine ecosystem.

The United States Geological Survey maintains stations for monitoring our nation’s surface water, including gauges along important rivers. The gauge in Kansas City and the gauge in Hermann both record the annual average discharge of the river at their respective locations going back to 1958 (See Figure 1). Though not perfect, the Kansas City gauge can give a rough estimate of the flow of the Missouri River entering the state. After passing Kansas City, several important tributaries enter the Missouri, including the Gasconade River, the Grand River, and the Osage River. The Hermann gauge can give an estimate of the flow after all of the major tributaries in the state have added their water to the total.

Figure 1. Data sources: United States Geological Survey, National Centers for Environmental Information.

Figure 2. Data sources: United States Geological Survey, National Centers for Environmental Information.

Figure 2 shows the average flow of the Missouri River in cubic feet per second, with Kansas City in blue and Hermann in red, and the scale against which you should read them is on the left. The third line, in green, is the annual precipitation in the Northern Rockies and Plains climate region, the approximate drainage basin of the Missouri River. Its scale is shown on the right, in inches of precipitation per year. I also had Excel calculate linear regression trend lines on all 3 series, and these are shown as dashed lines. In the interest of full disclosure, be sure to notice that the final data point in all 3 series represents only 7 years, not 10.

First, the flow at Herman is higher than at Kansas City. This is expected, because several tributaries add their flow to the river between Kansas City and Hermann.

Second, the trend for each series is slowly rising. With the severe droughts of recent years, this seems surprising.

Third, the variation in flow over time is very large, and the yearly variation dwarfs the change in the trend over time. At Hermann, the average yearly variation is 30% of the average streamflow. In fact, at Hermann, the highest annual streamflow (1993) was more than 4 times the lowest (2006).

Fourth, periods of high and low flow can last for five or more years.

Fifth, as I have noted in posts on climate change, the annual precipitation in the Northern Rockies & Plains also seems to be slowly increasing.

Just “eyeballing” the chart, the variation in streamflow between years seems to have increased over time, and so does the variation in precipitation. As noted above, the years of both the highest and lowest streamflows have occurred since 1990. If streamflow variation is, indeed, increasing, it opens both the potential for increased flooding and problems due to low water. I will look at this question in more detail in the next post.

Sources:

For river flow: United States Geological Service. National Water Information System: Web Interface. USGS Surface-Water Annual Statistics for Missouri. This is a data portal. Working your way through this data portal is tricky and complex. The sites used above are sites 06893000 (Kansas City) and 06934500 (Hermann). The parameter used was Discharge (sometimes called streamflow) in cubic feet per second. The dates used were 1958-2015. Data was downloaded 6/8/16, and the starting point for the data portal was at http://waterdata.usgs.gov/mo/nwis/annual/?referred_module=sw.

For precipitation: National Centers for Environmental Information. Climate at a Glace. This is a data portal. I selected Parameter: Precipitation, Time Scale: Year-to-Date, Month: Annual, Start Year: 1958, End Year: 2015, State/Region: Northern Rockies and Plains, and Climate Division/City: Entire Region. Data downloaded 7/9/16 from http://www.ncdc.noaa.gov/cag/time-series/us.

Missouri Riverine GAP Analysis

Missouri is home to more species than almost any other state in the union. Our fragmented and highly varied topography has led to many, many small, isolated areas in which evolution occurred along slightly different paths, leading to small communities of unique species. How well are we doing at protecting this biodiversity?

One way to assess how well we are protecting our biodiversity is through a gap analysis. The National Gap Analysis Program of the United States Geological Service (USGS) is intended to improve conservation practices by using the following process: first construct a map detailing land cover. Second, construct a map showing the distribution of animal and plant species. Third, construct a map showing the location and conservation status of protected areas. Fourth, use this data to identify gaps where target ecosystems and species are inadequately covered by conservation efforts. It sounds simple, but the process of doing it is quite complex.

Figure 1: Missouri Ecological Drainage Systems and Aquatic Ecological System Types. Source: Sowa (2005).

Figure 1: Missouri Ecological Drainage Systems and Aquatic Ecological System Types. Source: Sowa (2005).

Gap analyses are sometimes made separately for types of ecosystems. A Gap Analysis for Riverine Ecosystems of Missouri was published in 2005 by the USGS (Sowa, 2005). It constructs a gap analysis for Missouri’s streams. The authors constructed an 8-level classification hierarchy that could be used to map Missouri’s streams across the dimensions above (land cover, distribution of species, location and status of protected areas). I’m not going to explain all of the details here, but I do want to illustrate how their analysis proceeded.

Missouri is generally divided into three great hydrologic subregions. In the bootheel is the Mississippi Alluvial Basin. The Central Plains region lies north of the Missouri River and also wraps southward along the border with Kansas. In between is the Ozarks Region. If you have travelled in these regions, perhaps it was obvious to you that the streams in each one are quite different in character from those in the others.

The authors divided these three regions into Ecological Drainage Units. There were 19, and they are shown in Figure 1, delineated by the heavy black lines. These were further divided into 39 Aquatic Ecological System Types (AES-Types). Each AES-Type represented one or more drainage areas containing a small or medium, river with a unique combination of physical habitat, water chemistry, energy sources, hydrologic regime, and community of plants and animals. In Figure 1, the grey lines delineate the AES drainage areas, and the color codes for the AES-Type. AES-Types don’t have to be contiguous, they can be physically separated so long as they contain the same characteristics.

Figure 2: Missouri Valley Segment Types. Source: Sowa 2005.

Figure 2: Missouri Valley Segment Types. Source: Sowa 2005.

The authors then divided the AES drainage areas into even smaller units called Valley Segment Types (VSTs). VSTs were small reaches of streams that had similar characteristics. They identified over 100 different VSTs, and assigned them to literally thousands of small stream segments throughout the state (Figure 2).

The hypothesis of the analysis was that in coarser grained analyses, AES-Type would determine the species of plants and animals found within it, and that VST would play the same role in a finer-grained analysis.

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These analyses were then combined with management information about each stream segment. This primarily represented factors that either harmed or endangered the ecological diversity of the stream segment, like human encroachment, agriculture, and mining, or factors that protected the diversity of stream segments, like inclusion in a national forest, state park, or conservation area.

Figure 3: Human Stress Index. Source: Sowa 2005.

Figure 3: Human Stress Index. Source: Sowa 2005.

The authors represented the degree to which human activities impaired stream diversity by constructing a Human Stress Index, and Figure 3 shows the Human Stress Index for each of the AES drainage areas in Missouri. The higher the index, the darker the red, and the higher the degree of human disturbance.

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Figure 4: Percentage of VSTs with Gap Status of 1 or 2. Source: Sowa 2005.

Figure 4: Percentage of VSTs with Gap Status of 1 or 2. Source: Sowa 2005.

The gap analysis used a scale of 1-4 to rate the relative degree to which biodiversity was protected in each AES-Type and VST, with “Status 1” being most protected and “Status 4” being least. Figure 4 shows the percentage of VSTs in each Ecological Drainage Unit that were rated Status 1 or 2. As you can see, most of the EDUs had very low percentages of VSTs rated 1 or 2. Only those deep in the Ozarks had percentages above 26.5%.

Well, it is a very detailed and complex analysis. Trying to summarize the results is a little confusing. But the bottom line is that in the Central Plains Region of the state (the area north of the Missouri River, and then wrapping south along the Kansas border), only 11.4% of the VST’s were rated Status 1 or 2, while in the Mississippi Alluvial Basin 20.9% were, and in the Ozarks Region, 28.3% were. Throughout most of Missouri, the vast majority of land has been sufficiently degraded that it no longer protects Missouri’s biodiversity. (I have many previous posts about Missouri’s biodiversity, invasive species, and protected lands. To find them, look in the “Land” category of posts.)

To some extent, this finding should be expected; one would not expect urban or agricultural land to support the complex biodiversity that undisturbed land does. But the report puts numbers to that impression, and the result is not encouraging.

There is a great deal of additional information in the report, but it is complex and very detailed, and this post is already long enough. Those who have particular interests in biodiversity in Missouri should look up the report.

Sources:

Sowa, S. P., D. D. Diamond, R. Abbitt, G. Annis, T. Gordon, M. E. Morey, G. R. Sorensen, and D. True. 2005. A Gap Analysis for Riverine Ecosystems of Missouri. Final Report, submitted to the USGS National Gap Analysis Program. Downloaded 6/23/2016 from https://morap.missouri.edu/index.php/aquatic-gap-pilot-project.