Alaska Earthquake

On January 23, 2018 a 7.9 magnitude earthquake struck southeast of Kodiak Island in the Gulf of Alaska. According to the U.S. Geological Survey (USGS) this earthquake occurred as the result of strike slip faulting within the Pacific plate.

At the location of the earthquake, the Pacific plate is converging with the North America plate. The Pacific plate subducts beneath the North America plate at the Alaska-Aleutians Trench, about 90 km to the northwest of last week’s earthquake. The location and mechanism of the January 23rd earthquake are consistent with it occurring on a fault system within the Pacific plate before it subducts.

Subduction zones are plate tectonic boundaries where two plates converge, and one plate is thrust beneath the other. This process results in earthquakes and volcanoes. This earthquake hazards affects the area around the edges of the Pacific Ocean contains subduction zones. The largest earthquakes on Earth occur in these areas.

The approximately 2,500-mile-long Alaska/Aleutian subduction zone stretches from Russia to Alaska. Here, the Pacific Plate and the North American plate are moving towards one another at a rate of about 2-3 inches per year. The Pacific Plate is thinner and denser, so it is being thrust underneath the North American plate. This subduction zone has generated many large, devastating earthquakes, including the second largest earthquake ever recorded: the 9.2 magnitude Good Friday earthquake in 1964 that devastated Anchorage and other Alaskan towns and the resulting tsunami caused deaths as far away as California.

Large earthquakes are common in the Pacific-North America plate boundary region. In the last century alone, besides the 1964 9.2 magnitude earthquake, there have been 10 others with magnitudes over 7 that. have occurred near the Pacific-North America plate boundary region . Most of these have occurred on the subduction zone interface between the two plates, to the north and northwest of last week’s earthquake. This past weekend a series of light earthquakes struck Alaska, not at all uncommon in this region.

Also a series of light earthquakes (4.0-5.8 earthquakes) have struck southern California. A light earthquake occurred on Thursday, January 25, 2018. The magnitude 4.0 event occurred 8 miles northeast of Trabuco Canyon, CA followed this past week by several light earthquakes (the type you do not easily notice). Finally, in Ferndale, CA there were two earthquakes yesterday, a 5.0 and 5.8 magnitude.



The magnitude of an earthquake is expressed in whole numbers and decimal fractions. For example, a magnitude 5.3 might be computed for a moderate earthquake, and a strong earthquake might be rated as magnitude 6.3. Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in the estimate of energy, each whole number step in the magnitude scale corresponds to the release of about 31 times more energy than the amount associated with the preceding whole number value. The ways to calculate have evolved over time.

Oroville Dam not as Safe as “They” Say

On Sunday, February 12, 2017 residents of Oroville, California and nearby towns were ordered to immediately evacuate as the giant Oroville Dam emergency spillway began to crumble and the towns were threatened with flooding. The Oroville Dam is the tallest dam in the United States at 770 feet. The Oroville Dam and complex is part of the California State Water Project (SWP), the largest state-owned water storage and delivery system in the United States. The SWP is owned and operated by the California Department of Water Resources (DWR), which is part of the California Natural Resources Agency. The SWP provides water to about 25 million people and 750,000 acres of irrigated farmland in California. The design and construction of most of the SWP was completed in the 1960s and early 1970s. The Oroville Dam project was completed in 1968.

After years of drought, when the spillway had not been used, in January and February 2017, the spillway had its first significant discharges since 2011. From February 1, 2017 through the morning of February 3, 2017, service spillway discharges were generally about 15,000 cubic feet per second; then discharges were increased to about 25,000 cubic feet per second and maintained at that level until mid-day on February 6, 2017, at which time the release flow increased to between 42,000 and 45,000 cubic feet per second and held in that range until the morning of February 7.

As water flow from the winter storms increased, release flow was increased to and reached about 52,500 cubic feet per second on February 7th. Workers noticed significant disturbance in the service spillway chute flow and on-site Department of Water Resources (DWR) workers contacted DWR headquarters in Sacramento. An order to close the spillway gates was issued that same day. After the gates were closed, it was found that a significant section of the service spillway chute slab was missing, and as you can see below the damage to the spillway was very serious and had happened over a short period of time.

The flow that destroyed the spillway was a small fraction of the 300,000 cubic feet per second that the spillway was designed to handle. The chute failure happened in 2017 at a spillway discharge of about 52,500 cubic feet per second. The spillway chute had not failed previously during higher discharges, most recently a discharge in excess of 70,000 cubic feet per second in 2006, and historically discharges up to as much as about 160,000 cubic feet per second in 1997.

Back to last February, once damage to the spillway began, dam operators closed the gates and allowed the reservoir's water level to rise up to a concrete lip, known as a weir, on an emergency spillway. Responding to the damage to the service spillway chute, workers allowed the reservoir level to rise above the emergency spillway without a full understanding of relative uncertainties and consequences. It was the first time in the dam's history that the emergency spillway was used, and it quickly eroded the bare hillside under the weir and endangered the communities downstream that lead to the evacuation order.

After the Oroville Dam spillway incident in February 2017, the Federal Energy Regulatory Commission (FERC) required the California Department of Water Resources (DWR) to engage an Independent Forensic Team (IFT) to investigate the incident. Their report was released this month and casts a shadow over the integrity of the Oroville complex and possibly more of the California State Water Project infrastructure.

The forensic investigation found that water that penetrated through cracks and joints that lifted entire sections of the spillway and eroded the underlying soft rock. Also playing a role were thin concrete, weak anchors into the underlying rock and corroded steel reinforcement.

Although the poor foundation conditions at both spillways were well documented in the original geology reports, these conditions were not properly addressed in the original design and construction. The forensics team found that one of the key Oroville spillway designers was hired as a postgraduate with no engineering experience in spillways. After construction all subsequent reviews mischaracterized the foundation as good quality rock. As a result, the significant erosion of the service spillway foundation was also not anticipated.

Not long after the spillway was completed in the 1960s, cracks began developing that indicated problems, but the department soon considered those to be normal and never questioned the original design or construction. The report found that periodic inspections over the 50 year history of the spillway failed to identify the original design flaws and the subsequent deterioration of the spillway's integrity.

The seriousness of the inferior construction and lack of repair durability was not recognized. Over time, chute flows and temperature variations led to progressive deterioration of the concrete and corrosion of steel reinforcing bars and anchors. Indications of deterioration were ignored. The forensics team noted that a comprehensive review of the original construction and design and whether it meets modern standards should have been conducted long ago. Such a review is warranted for the entire Oroville Dam, since the engineering shortcomings in the spillway could be present in the earthen embankment as well.

Ethiopia’s Nile Dam-Tensions Mount with Egypt

from World Bank

The Grand Ethiopian Renaissance Dam is located in the headwaters of the Blue Nile the major tributary to the Nile River. The hydroelectric dam is planned to produce 6,400 megawatts of electricity and will be completed next year. Once completed the dam will be Africa's largest hydroelectric power plant and will boost the economy and influence of Ethiopia. However, to work, the 74 billion cubic meter reservoir behind the dam must be filled.

The Blue Nile originates in Ethiopia and flows into Sudan, where it joins with the White Nile, whose source is Lake Victoria in east Africa. Downstream of the Dam is Egypt, a desert nation that derives 90% of their water supply from the Nile River. Few nations rely so completely on a single river.

Current plans call for Ethiopia to fill the reservoir behind the Grand Ethiopian Renaissance Dam over three years. Justifiably, Egypt fears that filling the reservoir will reduce its water supply, destroying parts of its farmland and squeezing its population of 96 million people, who already face water shortages.

One study by a Cairo University agriculture professor estimated Egypt would lose over half of its farmland if the reservoir is filled in three years. A slower, six-year fill would cost Egypt 17% of its cultivated land, the study claimed. Once the fill is completed, the Nile flow would in theory return to normal, but control of the Nile flow would belong to Ethiopia. They claim that the impact from filling the reservoir will be far smaller. Some believe Egypt could suffer no damage at all if both countries work together adjusting the rate of filling the reservoir to ensure that Egypt's own reservoir, Lake Nasser, stays full enough to meet its needs during the fill. However, no one has a clear idea what impact Ethiopia's dam will actually have and this is about power and Addis Ababa’s ambitions for himself and his nation.

The Nile River moves through Burundi, Egypt, Ethiopia, Kenya, Rwanda, Sudan, Tanzania, Uganda, and the Democratic Republic of the Congo. Each country views the Nile as at least partly their own. According to treaties from 1929 and 1959 put in place by the British, the northern states of Egypt and Sudan were allocated 75% and 25% of the Nile’s water respectively, with none allocated to the source nations. This was done because Egypt and Sudan are arid countries with almost no other access to fresh water other than the Nile.

Egypt receives the lion's share of Nile waters: more than 55 billion of the around 88 billion cubic meters of water that flow down the river each year. Still, Egypt has one of the lowest per capita shares of water in the world, some 660 cubic meters a person. Egypt's population was 19 million in 1947 and has reportedly reached 96 million today. In its 2013 report, titled “Water Resources and Means to Rationalise their Use,” Egypt revealed that each Egyptian's annual share of water declined from a water surplus of 2,526 cubic meters in 1947 to a sufficient level of 1,972 cubic meters in 1970 (when their population was around 35 million), and then water poverty with 663 cubic meters in 2013. The flow of the Nile has not increased and it is the limiting factor in the growth of Egyptian population and their economy.

Official forecasts are that Egypt will double its population in 50 years. There is simply not enough water and control of the water may now belong to Ethiopia. In a 2015 Declaration of Principles agreement, Egypt, Ethiopia and Sudan agreed to contract an independent study of the dam's impact and abide by it for filling the reservoir and operating the dam. However, the deadline to complete the study has passed, and little progress has been made.

Egypt, Sudan and Ethiopia re in negations as Egypt faces not only the limitations on the flow of the Nile, but also the shifting of power now that Ethiopia will to a large extent control the flow of the Nile. The “Quartz Africa” and “The New Arab” report that regional tensions are growing. Egypt believes al-Bashir is on Ethiopia’s side and has proposed excluding Sudan from the negotiations. Sudan’s shift is reported due in part because of what it stands to gain including electricity supply and flooding prevention during rainy seasons. The Egyptian government has publicly ruled out military action after suggesting it in 2013, but in recent months officials have escalated their rhetoric.

For Ethiopia, the $5 billion dam is the realization of a dream. Ethiopia's infrastructure was among the least developed in the world, leaving most of its 95 million people without access to electricity. The hydroelectric dam will have the capacity to generate over 6,400 Megawatts, a massive boost to the current production of 4,000 Megawatts. The electric power and water will shift the geopolitical forces of the region.

Well Testing in Prince William

According to the 2017 Annual Report for the Virginia Household Water Quality Program from Virginia Tech, there are 1.7 million Virginians or 22% of the state’s population get their household water from a private well. Municipal water supplies are regulated and regularly tested under the EPA’s Safe Drinking Water Act. Private wells are the responsibility of the well owner.

Household water quality is driven by geology, well construction and condition, nearby sources of groundwater contamination, and any water treatment devices and the condition and materials of construction of the household plumbing. To ensure safe drinking water it is important to maintain your well, test it regularly and understand your system and geology.

The Virginia Household Water Quality Program where I volunteer provides affordable, confidential water testing and education to well owners in Virginia. Every year the program holds water clinics in various counties. Last year 2,178 wells were tested in 87 counties. Prince William will be having a water clinic again this year.

Water samples will be tested for: iron, manganese, nitrate, lead, arsenic, fluoride, sulfate, pH, total dissolved solids, hardness, sodium, copper, total coliform bacteria and E. Coli bacteria. What we test for are mostly the naturally occurring contaminants and common sources of contamination: a poorly sealed well or a nearby leaking septic system, or indications of plumbing system corrosion. Though this is by no means an exhaustive list of potential contaminants, these are the most common contaminants that effect drinking water wells.

The chart below shows what we found in the 101 private wells tested in the first round of testing we did in Prince William County in 2017.

To avoid having too many people show up on the day of the clinic and long lines for check in this year the program is asking participants to prepay for the analysis. Sample kits are $55 each. Pre-payment can be made in person or by mail at the VCE office at 8033 Ashton Avenue, Suite 105, Manassas VA 20109.

Make checks out to “Treasurer, Virginia Tech”. To register for this class, or to ask questions about the program, please call 703-792-7747 or master_gardener@pwcgov.org

The Prince William Drinking Water Clinic has 3 parts:
1. The Kick-Off Meeting on March 26th from 7-8:30 pm at PWC Board Chambers in the McCoart Building, 1 County Complex, Woodbridge, VA 22192 introduces water quality concerns in our area and hands out the water sampling kits.

2. The Sample Drop Off on March 28th from 6:30am-10am ONLY at the VCE Office, 8033 Ashton Ave., Manassas 20109

3. The Results Interpretation Meeting on May 9th from 7-9 pm at PWC Board Chambers in the McCoart Building, 1 County Complex, Woodbridge, VA 22192 will explain the report, include a discussion and answer questions on dealing with water problems.

Water Samples must be dropped off on Wednesday March 28, between the hours of 6:30am and 10am at the VCE - Prince William Office, 8033 Ashton, Suite 105, Manassas, 20109. NO EXCEPTIONS for sample drop off. However, if you are unable to attend the kick off or results meetings arrangements can be made to pick up a test kit or your results at another time, please call 703-792-7747 or master_gardener@pwcgov.org for assistance.

Radium in Mid-West Groundwater

Since the 1950’s it has been known that groundwater from the Cambrian-Ordovician (C-O) aquifer system contained radium (Ra 226 and Ra 228) at concentrations that frequently exceed the US Environmental Protection Agency (USEPA) safe drinking water maximum contaminant level (MCL) of 185 mBq/L; 5 pCi/L. This aquifer provides more than 630 million gallons of water a day for public supply to parts of Illinois, Iowa, Michigan, Minnesota, Missouri, and Wisconsin. In addition, more than half a million people get their drinking water from private wells that tap the Cambrian-Ordovician aquifer.

A newly published U.S. Geological Study, part of the USGS National Water Quality Assessment Project, investigated the conditions that cause these unusually elevated levels of radium in the groundwater from the Cambrian-Ordovician aquifer. Knowing where and how much radium is in groundwater is important because of the health risks associated with drinking water that’s high in radioactive isotopes. Known health risks include an increased incidence of bone cancer and leukemia.

The USGS examined several variables like groundwater age, dissolved minerals, and dissolved oxygen levels in 80 samples collected across the six states. The researchers were able to better understand the conditions that cause radium to leach from the underlying geology into groundwater at higher levels.

They found that water that was recharged into the aquifer long ago, that contains greater amounts of dissolved minerals, and that is low in dissolved oxygen is more likely to leach radium from its surrounding rock. The estimated mean groundwater ages ranged from 19 years to more than 1 million years. Only eight samples had groundwater recharged since about 1950. The USGS found that more than 80% of the groundwater was older than 1,000 years. They also found that the proportion of the three Ra isotopes differed between the regionally unconfined and confined areas of the aquifer system.

Increased concentrations of Ra 226 was found in confined regions of the aquifer. The rate of groundwater flow in the confined area of the aquifer is very slow because relatively stagnant saline water restricts the movement of freshwater into deeper parts of the basins. Total Radium concentrations were significantly lower in HCO3 dominated, oxic samples from the unconfined area of the aquifer as compared to SO4 or Cl dominated, anoxic samples from the regionally confined areas.

Measured concentrations of all three Ra isotopes were significantly correlated with mean groundwater age reflecting the increased mobility of Ra with increasing mineralization and Fe-reducing conditions. The development of anoxic, Fe-reducing conditions and increasing water mineralization with groundwater age favors the mobilization of Ra and results in the frequent occurrence of Rac concentrations greater than 185 mBq/L (5 pCi/L) in the regionally confined area of the aquifer system. Under anoxic, Fe-reducing conditions, Fe- and Mn-hydroxides are dissolved, thereby reducing the adsorptive capacity of the aquifer solids.

No testing was done of the relatively shallower private drinking water wells. These well owners might consider having their water tested for radium as part of their regular well maintenance.

Preventing Frozen Pipes

If during the recent cold snap you turn on a faucet and either get nothing or just a trickle you might have had a frozen pipe. If your well supply line or the water main is not frozen, you may have water in part of the house, but frozen pipes elsewhere. There are some things you can do to prevent frozen pipes in the future. A couple of ceramic electric heat cubes, thermocouple, electric blanket and a little strategy can prevent frozen pipes.

The likely pipes to freeze are against exterior walls of the home, or are exposed to the cold, like outdoor hose bibs, and water supply pipes in unheated interior areas like basements and crawl spaces, attics, garages, or kitchen cabinets. Pipes that run against exterior walls that have little or no insulation are also subject to freezing. It is easier to prevent pipes from freezing than to unfreeze them.

In sub-zero weather wells with and without separate well houses can freeze. Keeping the temperature in a well house above freezing or your well pipe insulated can prevent this. It used to be that an inefficient 100 watt incandescent bulb gave off enough heat to do the job, but now with more efficient bulbs insulation and other sources of heat have to be used. An electric blanket can do the job.

While a deep well is unlikely to freeze because the temperature below the frost line (about 3 to 5 feet below the surface) remains at a nearly constant temperature, in the range of 45 -70 degrees Fahrenheit depending on your latitude. However, if the pitless adaptor or pipe from the well is not deep enough to be below the frost line then that line will freeze. Abnormal artic frosts can identify many a private well line that was not buried deep enough at its most vulnerable point where it connects to the foundation. 

The enclosure protects the well head and wraps well pipe with insulating matuerial

Though, our well line runs under the garage into the house. The highest point of my lot is right about there and the basement floor where the water line enters the house is about nine feet below ground. The water pipe enters the wall bout 3-4 feet above the basement floor. That is well below the frost line. Even the winter when the temperature fell to 14 below one weekend the main water line did not freeze. However, if your well pipe is shallower or like me have pipes that run over sections of the garage it is important to keep your garage temperature on extreme days above freezing and you might have to keep a crawl space or the area next to the well pipe entry warm. My furnace and hot water heater are right next to the entry point and pressure tank. It’s always warm there (the cat loves it). 

Because of the usually mild winters here in Virginia, our house was built with a Jack and Jill bathroom partially above the garage. There were indications that a couple of pieces of wall bard in the garage had been replaced. So, the year we bought the house I ripped out all the wall board and insulated the heck out the garage and the dormer above it, replaced the garage door with an insulated door, and wrapped the pipes in foam.

Heat cube with thermocouple in garage

Unfortunately, that 14 degrees Fahrenheit below day still froze the pipe to that bathroom. So now, I keep a small ceramic electric heater ($40) connected to a thermocouple that turns it on when the temperature in the garage falls below 40 degrees Fahrenheit. I turn on the heating cube in the garage and check it functioning when I turn off the hoses in late falls. When the weather is forecast to fall into the single digits or lower I open the cabinet below the sink and in the most extreme weather run an extra ceramic electric heater overnight keeping that bathroom toasty while the rest of the house is at 65 degrees. You might also need to have the same set up in a crawl space or possibly a basement.

Letting the water run in very cold weather can work, but can also create other problems. While running water may prevent the water supply pipes from freezing, in the coldest weather the slowly running water might cause the drain pipe to the septic system to freeze and block the flow or even burst, and it can overwhelm a septic system. My septic line leaving the house is on the lowest elevation and not particularly deep. Certainly, the septic line is not below the actual frost line during exceptionally cold weather. I baby and protect my septic system.

California’s Digital Elite Drinking Untreated Water

A New York Times story last week took a look at the wealthy Silicon Valley residents who are drinking and selling water that is “off the water grid." Some collect water from springs themselves; some buy from companies like Live Water, which charges almost $40 for a 2.5 gallon jug and $15 for refills; and others have installed expensive systems to collect water from the air- in the state with the most areas that cannot meet the U.S. EPA air quality standards.

Springs occur wherever groundwater flows out from the earth’s surface. Springs typically occur along hillsides, low-lying areas, or at the base of slopes. A spring is formed when natural pressure forces groundwater above the land surface. Springs are highly susceptible to contamination since they are fed by shallow groundwater, which usually flows through the ground for only a short period of time and may interact with surface water. For this reason, most springs will need some treatment before the water is considered a reliably safe source of drinking water. However, don’t let science and common sense get in the way of yet another thing the California Digital Elite can get venture capital (other people’s money) and sell at a premium.

Let me clue you in on a bit of history then science. Though filtration was the first water treatment, true water treatment came out of the advances in scientific understanding. Filtration and additives like alum are effective treatments for cloudy water or turbidity, but it has limited success in removing pathogens which cause diseases like typhoid, cholera, and dysentery. The discovery in the early 1900’s that chlorine and ozone were effective disinfectants for the treatment of water to eliminate pathogens were the beginning of the modern scientific era and the birth of the great nations.

The first standards for bacteria in drinking water in the United States (1914) applied only to water carried on interstate boats and trains. The Public Health Service expanded water standards beginning in 1925 with the most rudimentary standards. This was expanded in 1946 and 1962 and finally Congress passing the Safe Drinking Water Act of 1974. The SDWA was further amended in 1986 and 1996. Today there are almost 90 substances tested for and controlled under the SDWA.

Since the advent of the Clean Water Act, outbreaks of disease caused by drinking water are no longer common in the United States. However, waterborne disease outbreaks continue to occur in the U.S. and can lead to serious acute, chronic, or sometimes fatal health consequences. The Center for Disease Control and Prevention (CDC) collects data from all the states on waterborne diseases. From 1971 to 2002, there were 764 documented waterborne outbreaks associated with drinking water, resulting in 575,457 cases of illness and 79 deaths. The symptoms of water borne disease often include diarrhea, nausea, vomiting and sometimes fever. It is not uncommon to mistake a case of water related disease for “food poisoning” or a “24-hour stomach virus.” Contaminated water can often look, smell and taste fine. Giardia or Cryptosporidium, two microscopic parasites that can be found in surface water like these springs for example. Both parasites produce cysts that cause illness and sometimes death.

Self-styled water experts, these entrepreneurs share a wariness of tap water, particularly the fluoride added to it and the lead pipes and aging infrastructure that some of it passes through. These water entrepreneurs contend that the wrong kind of filtration removes beneficial minerals. Traditional bottled spring water is sterilized using UV light, chlorine or ozone gas and filtered to remove parasites and algae. The new water entrepreneurs say that water treatment kills healthful bacteria something they call “probiotics” or promoting of intestinal flora. They crow that their water turns green if it’s not consumed within a month.

The off-the-grid water movement has become more than the fringe phenomenon it once was, with sophisticated marketing, cultural cachet, millions of dollars in funding and influential supporters from Silicon Valley. It has become a danger to public health. Look, I know there are some reasons to be concerned about public water supplies. In truth, I have my own private off-the-grid water supply. My water comes from groundwater in the fractured rock system here in the Piedmont of Virginia. Rain water and snow melt percolate into the ground and recharge the aquifer. My house was picked for the water quality (among other things). The water in my well is relatively young, is untreated but is tested twice a year (by me) to ensure it remains free of contaminants and tastes great. In Virginia about 21% of the population obtains their household water from private domestic wells. If you want to drink off the grid water, come to Virginia.