Blog Action Day 2010

Today is Blog Action Day 2010 and the topic at hand is water. When I think about the many issues surrounding water, it's hard for me to pick just one to write about.

In James McBride's memoir / family retrospective The Color of Water, the author asks his mother, "What color is God's spirit?" She replies, "It doesn't have a color ... God is the color of water."

I like that quote. It seems fitting, somehow, since "up to 60% of the human body is water" (source: USGS). We live on a planet where 71% of the Earth's surface is covered by water (source: NASA). Water is integral to our daily lives. Regardless of race, class, gender, income, or other dividing lines, every person on earth depends upon water. It is our lowest common denominator. We all need water to survive.

Yet, only 3% of the Earth's water is available as fresh water suitable for drinking (source: NASA). According to the UN, "[one] billion people lack access to [an] improved water supply." Worse, "2.6 billion people lack access to improved sanitation" and "[i]f the 1990-2002 trend continues, it is thought that some 2.4 billion people will be without improved sanitation in 2015 - almost as many as are without today" (source: UN).

What can be done? Blog Action Day is calling upon people to sign a petition supporting the UN's efforts to bring clean water and sanitation to the developing world. The hope is that Blog Action Day will bring attention to this growing, glaring problem and, hopefully, will spur positive change. The United States Fund for UNICEF is sponsoring this petition.

Petitions by Change.org|Start a Petition »

Happy World Water Monitoring Day!

According to my handy-dandy, newly compiled Calendar of Science Holidays, today is World Water Monitoring Day. According to the World Water Monitoring Day website, the purpose of this day is to encourage people to identify their local water bodies (like rivers, lakes, streams, oceans) and take steps to protect them by conducting basic water monitoring.

The World Water Monitoring Day website tracks water quality monitoring data from around the world. Local groups upload their findings by geographic location. The basic water monitoring measures tracked for this website are pH, dissolved oxygen (DO), temperature, and turbidity. These measures are important for many reasons, but here's some information on how they affect aquatic life:

pH tells you if the water is acidic, basic (alkaline), or neutral. Water with high acidity or high alkalinity is not healthy for aquatic life. Natural waters should have a pH that is roughly neutral.

Dissolved oxygen tells you how much oxygen in the water is available to aquatic life. For example, if lake water has low dissolved oxygen, the fish won't be able to breathe. In general, water bodies that are in motion (streams, rivers) have higher dissolved oxygen than stagnant water bodies like lakes and ponds.

Temperature is a useful measure of a water body's resilience to atmospheric temperature changes. Let's say that one day, the temperature outside is 90 degrees F and the next day it drops down to 40 degrees (this can happen where I live!). If water temperature in lakes and streams followed those extremes, most - if not all - aquatic life would die. But water generally heats and cools more slowly than air, which allows lakes and streams to withstand daily atmospheric temperature fluctuations. When you monitor water temperature, you don't want to see rapid changes over short periods of time. If a polluter suddenly dumped a large volume of hot wastewater into a small stream, for example, you would see a big temperature difference from one day to the next and you might see lots of dead fish floating on top of the water.

Turbidity looks at the amount of suspended material in the water. Very turbid water can look green from high concentrations of algae or brown from suspended sediments. Often, pollution increases turbidity. Crystal clear water, however, doesn't guarantee that a water body is healthy. Sometimes, it means that the water is "dead" and that no aquatic life is living there. Fish need algae and other suspended materials for food.

A Secchi disk is used to measure the turbidity of your water. You basically drop it down into a water body until you can't see it any more and measure at what depth that occurs.
Photo credit: Secchi Dip-In | Biological Sciences Department Kent State University

To learn more about these four water quality measures, check out this page of World Water Monitoring Day handouts or visit EPA's Volunteer Monitoring Program. In the US, you can find local monitoring clubs at EPA's Surf Your Watershed. Check with environmental groups in your area to see if they offer water quality monitoring classes. Getting to know your watershed is a great way to get acquainted with your local environment.

World Water Monitoring Day - What's Your pH?

In honor of World Water Monitoring Day, which occurs on September 18, let's talk about pH:

A pH test lets you know if your water is acidic or basic. The scale runs from 0 (very acidic) to 14 (very basic). Natural waters, according to the EPA, usually have a pH between 6.5 and 8.5. On this scale, 7 is the midpoint and it is considered neutral (neither basic nor acidic). Values at either end of this scale (like battery acid, with a pH of less than one, or lye, with a pH of greater than 12) are very hazardous to people.

Image credit: Environment Canada
(who had nothing to do with this blog post but kindly made this nice chart available for reprint)

pH can be measured in different ways, but test strips are commonly used because they are inexpensive and easy to read. You just dip the strip into the water and the strip will change colors. Then you compare the new strip color to a chart of different shades. The color that matches best is a rough guess of your pH. You can pick up pH test strips at your local pet supply store in the aquarium department.

What do the results mean? Let's say that you measured the pH in a stream in your neighborhood and it was below 6. This acidic water might be causing stress to aquatic life like algae and fish. The acids in water might be reacting with metals (copper, lead) in the sediments, causing these substances to enter the water column. Since natural water wouldn't usually have a pH that low*, you'd have a pretty good idea that the water was polluted. Maybe a chemical plant upstream was dumping their effluent - treated wastewater - into the stream and causing these changes. Reporting your findings to a local environmental monitoring agency could lead to finding and stopping the source of the pollution.

Although pH test strips are usually used to check the water in streams, ponds, or your own drinking water supplies, you can test any fluid or even moist solids, like soil. One day, when I was working in a laboratory at college, I stuck one into a can of soda. I remember that my drink had a pH of 3 and I wondered if I should be sticking something so acidic into my body on a regular basis. For reference, the pH of lemon juice is around 2 or 3. Can you imagine drinking a can of lemon juice?

Now, to be fair, lemon juice and soda aren't as close as they seem on the pH scale. The pH scale is logarithmic. With 7 as neutral, that means that a fluid with a pH of 6 would be a 10 times stronger acid than neutral, one with a pH of 5 would be 100 times stronger than neutral, and so on. This image gives a nice sense of the logarithmic nature of the values.

Note to my friends in Texas or New Mexico: In honor of World Water Monitoring Day, Chazimal National Memorial is providing free water testing kits for classes in your area. Each kit has 50 pH and oxygen tests. From their newsletter: to receive your free test kit, contact Chamizal staff at 915-532-7273 ext 130 or email cham_education (at) nps (dot)gov.


* Keep in mind that some areas have acidic water due to naturally occurring conditions - maybe the bedrock or soils near the stream are naturally acidic. If you want to monitor surface water in your area, it's always good to check with your local water quality monitoring groups. They can tell you what values are considered normal for where you live. Check EPA's Volunteer Monitoring page to find a group in your area.

Happy World Water Day!

Thanks to Jason at CephalopodCast, I learned that today, March 22, is World Water Day. This annual global observance started in 1993 through the work of the United Nations. Over 35 countries around the world have special water-themed events planned to mark the occasion.

Why have a special day about water? With nearly 3/4 of the earth's surface covered in seawater, it might come as a surprise that fresh water is a scarce resource on our planet. According to the US World Water Day website, "nearly one billion people around the world don't have clean drinking water, and 2.6 billion still lack basic sanitation."

What can we do about it? Remember that fresh drinking water is precious -- some people don't have any! Try your best not to waste water:

* Don't leave the faucet running when you brush your teeth.

* Be sure to fix leaky faucets and running toilets.

* Try to take less time showering. Use a timer and challenge everyone in your family to beat your time.

* Don't flush the toilet unless it's truly necessary.

* Don't dump medicine down the toilet. Some medicines are not easily removed by sewage treatment plants and these chemicals can wind up in our water supply.


Enjoy the water that you drink today!


Photo credit: Alberto P. Veiga, via flickr // CC BY 2.0

How big are raindrops?

Photo credit: Leon Brooks, BurningWell.org

While I was taking out the trash the other night, I commented to my young son that it was misting outside.

He gave me a funny look and said, “It’s raining.”

I said, “No, it’s misting. It’s not coming down hard enough to be rain.” I started to tell him about the different ways that people might describe rain, like drizzle or light showers, but I stopped short.

How do we define rain? What are the actual meteorological classifications of liquid precipitation? I thought that this would be a simple question, but there's been some debate on the subject.

According to the National Oceanic and Atmospheric Association, drizzle consists of fine water droplets with diameters of less than 0.5 mm; rain is usually larger than 0.5 mm. Fog droplets are similar to drizzle, but they don’t hit the ground.

I found an older set of definitions from the U.S. Department of Agriculture, though the U.S. Geological Survey at The Water Cycle: Precipitation. The 1959 USDA table referenced on this site has definitions for precipitation that include fog, mist, drizzle, light rain, moderate rain, heavy rain, and cloudburst. Part of this table included the median diameters of different precipitation droplets, including 0.96 mm for drizzle and 1.24 mm on up for rain (note that these don't exactly match the NOAA definitions).

I couldn’t wrap my mind around the numbers, so I took the data about droplet sizes and made my own graph. I discovered a couple of interesting things when I sat down with the numbers.

Data taken from a USGS adaptation (The Water Cycle: Precipitation) of Lull, H.W., 1959, Soil Compaction on Forest and Range Lands, U.S. Dept. of Agriculture, Forestry Service, Misc. Publication No.768
First, none of the droplets are very big. Even the largest water droplet -- occurring during a cloudburst -- is extremely small, typically measuring less than 2/10 of an inch in diameter. (Now, I don’t know about you, but I’ve had raindrops fall in my eye and it’s hard for me to believe that they are usually so tiny.)

Second, comparing droplet sizes reveals enormous differences between the categories. Cloudburst droplets (at 2.85 mm in diameter) are over 200 times larger than fog droplets (0.01 mm in diameter).

How do scientists know these things? Here’s one way: In 1971, researcher Motoi Kumai went out into the fog armed with gelatin-coated glass slides and studied the results under an optical microscope. He measured the radii of about 20,000 fog droplets for his paper, published in the Journal of Atmospheric Sciences in 1973. (You can read Arctic Fog Droplet Size Distribution and Its Effect on Light Attenuation in the online journals at the American Meteorological Society. Interesting side note: Kumai found that long-lasting fogs have larger water droplets than short duration fogs.

So, how big are raindrops, anyway? See for yourself! The next time you see a storm brewing, take a piece of colored construction paper outside and lay it securely on the ground. Let the first few raindrops fall and then grab your paper and quickly run inside before you both get drenched. The water droplets should have made marks on your paper; you can take your own measurements. Do you think that your results will be the same or different than those found by the meteorologists? Why?

Drought for thought

Photo credit: Jon Sullivan
When I was in graduate school, we spent some time discussing natural disasters and their impacts on humanity. I was surprised to learn that drought was considered to be a significant natural disaster. In the United States, yearly drought-related costs are higher (on average) than flood and hurricane-incurred costs combined. (source: Drought for Kids: Comparison of Droughts, Hurricanes and Floods by the National Drought Mitigation Center of the University of Nebraska-Lincoln)

What is drought? Simply put, a drought occurs when there is a substantial lack of rainfall in a given area, enough to negatively impact people, plants, and animals.

The definition of drought, however, is unique to a given location. What would be considered a drought in the wetlands of southern Florida, for example, would be considered an abundance of rainfall in the United States’ desert southwest.

There are a couple of factors that make coping with drought challenging. For one, by the time that you realize you are in drought, it’s already begun. Pinpointing when a drought first starts is nearly impossible, although groups like the United States Geological Survey do an admirable job of searching for signs of trouble. (Among other things, the USGS monitors the flow of water in streams and rivers. Low flow signals a possible drought-related problem.)

Once you realize that you are in a drought, no one can say how long it will last. Rainfall models can only tell you so much. For city planners and others who regulate water flow, it can be difficult to decide when and how to moderate water intake. Imposing water restrictions, ironically, can make a drought situation worse if panic ensues and people begin to hoard water. UNL’s National Drought Mitigation Center describes the challenge of managing drought as "The Hydro-Illogical Cycle".

In the United States, the U.S. Drought Monitor keeps track of drought conditions. One place to check on world-wide drought situations is NASA’s Earth Observatory Natural Hazards: Crops & Drought.

Project WET

When I was in graduate school, I was fortunate to have taken a number of interesting science education classes. One of these was a workshop based on Project WET, a non-profit water education program for science educators. The Project WET Curriculum and Activity Guide is geared toward students ages 5 through 18. The nice thing about the book is that there are charts in the back, breaking down the activities by grade levels (K-12), time required, subject areas, topics, and things like group size. Activities range from looking for contaminants in soil, to holding water court, to imagining yourself as water. You can download a sample activity on Project WET’s Kids Page.

Is it time for a water audit?

How much water does your family use in a month? If your family is anything like ours, the answer is too much. We routinely take long showers, rewash laundry left forgotten in the washer, and leave the tap running when we brush our teeth.

So ... maybe it's time for a water audit. Find your latest water bill and sit the family down for a meeting. Brainstorm ways to reduce your water consumption. Don't forget to add any silly and outrageous ideas. If your son wants to stop taking baths, add that to the list. If your mom wants to eat out every night so she doesn't have to wash the dishes, write that down too.

When you have compiled a long list of possible choices, discuss your options. Which ones are workable? Which ones are likely to have the greatest impact? Take a family vote and pick your favorite. Try one water-saving idea for the next month. When your next water bill arrives, sit the family down again and see if it made a difference.

If so, keep doing that idea and add a new one. If your first idea didn't make much difference, don't get discouraged. Try another one. Check back monthly and see how much water -- and money -- you are saving.