These are tests we run to figure out the makeup of the water.
To read about how we gather the samples for testing go to the Data page.
*Descriptions from GLOBE teacher handbook (www.globe.gov)

DO
pH
Alkalinity
Nitrate
Electrical Conductivity
Transparency
Macroinvertebrates
Flow Rate
Temperature

DO- Dissolved Oxygen. This is the concentration of oxygen dissolved in water and readily available to fish and other aquatic organisms. The ability of water to retain oxygen decreases with increasing temperatures or dissolved solids. Adequate concentrations of dissolved oxygen are necessary for life of fish and other organisms and the prevention of offensive odors. The higher the DO the better.

pH- This is a measure of the acid content of water. The pH of a water influences most of its chemical processes. Pure water with no impurities (and not in contact with air) has a pH of 7. Water with impurities will have a pH of 7 when its acid and base content are exactly equal and balance each other out. The pH scale ranges from 1 to 14. 1 being the most acidic and 14 being most basic. 7 in neutral. The pH scale is different form the concentration scale we use for other impurities. It is logarithmic, which means that a one-unit change in pH represents a factor of ten change in the acid content of the water. Thus water with a pH of 3 has ten times the acid content of water with a pH of 4.

Alkalinity-This is a measure of a water's resistance to the lowering of pH when acids are added to the water. Acid additions generally come from rain or snow, though soil sources are also important in some areas. Alkalinity is generated as water dissolves rocks containing calcium carbonate such as calcite and limestone. When a lake or stream has too little alkalinity, typically below about 100 mg/L, a large influx of acids for a big rainfall or rapid snowmelt event could (at lest temporarily) consume all of the alkalinity and thus drop the pH of the water to levels harmful for amphibians, fish or zooplankton.

Nitrate-This is one of the most important elements for plants to grow in both fresh and saline waters. It is usually only present in suboxic waters (low dissolved oxygen levels). The nitrate form of nitrogen found in natural waters comes naturally from the atmosphere in rain, snow, fog or dry deposition, or from the decay of organic material in soil and sediments. It can also come from agricultural runoff; farmers add nitrogen fertilizer to crops, some of which drains out of the soil when it rains.

Electrical Conductivity-Pure water is a poor conductor of electricity. It is the impurities in water, such as dissolved salts, that enable water to conduct electricity. Since we lack the time or money to analyze water for each substance, we have found a good indicator of the total level of impurities in fresh water to be its electrical conductivity- how well a water passes electrical current. The more impurities the greater its electrical conductivity. For most agricultural and municipal uses, we want water that has an electrical conductivity below about 1500-1800 micoSiemens/cm for usage in watering our plants. For household use we prefer to have an electrical conductivity below 750 microSiemens/cm.

Transparency-"Transparency is the measurement of water clarity. How clear the water is
at your site will depend on the amount of soil particles suspended in the
water and on the amount of algae or other growth at your site.
Transparency may change seasonally with changes in growth rates, in
response to precipitation runoff, or for other reasons. The clarity of
your water determines how much light can penetrate. Since plants require
light, transparency becomes an important measurement in determining the
productivity of your water site."

We use the turbidity* tube, which is a clear plastic tube that is 1 meter
high. It has a stop-valve at the bottom, and a miniature Secchi disk (dark
and light pattern) inside the tube, on the bottom. We fill the tube with
water from the river and then let it drain out until we can just begin to
see the pattern on the bottom. We note the height of water in the tube and
repeat this procedure three times. We record the average of these three
measurements.

*The word "turbidity" indicates the cloudiness of the water. It is the
opposite of "transparency." Use of transparency is a determination of how
clear the water is. If we use the word "turbidity" then we are looking for
a measure of how cloudy the water is. It's a little like saying it's
"partly sunny" instead of saying "partly cloudy."

Macroinvertebrates-The prefix "macro-" means "large." So, macro-invertebrates are invertebrates (animals that lack backbones) such as crayfish, insects, snails, and mussels or clams that are large enough to be seen without magnification. If they were "micro-" they would be too small to be seen without a magnifying lens.

Invertebrates are an important link in the food chains of river systems. As primary and secondary consumers, they help to process matter and by feeding on algae, bacteria, and plants and even some decaying matter in the water. Their waste also contributes to the nutrient level of the water in which they live.

We examine the types of invertebrates found in the sediments or along the bottom of the river (benthic organisms) to learn more about the quality of the river water. Water quality is affected by substances that are dissolved in the water such as oxygen and chemical pollutants. Conditions such as temperature, pH, and the amount of algal growth or suspended sediments also affect the types and number of organisms that can live in the river. The invertebrates serve as a crude measure of the water quality because some invertebrates are more tolerant to bad conditions than others. Finding higher numbers of "tolerant" species means that the water quality is bad. Finding few of the tolerant types and more of the intolerant
species would mean that the water quality is good.

Invertebrates are useful as indicators of water quality because they are not easily able to leave the environment when changes occur, some spend different phases of their life cycles in the river water throughout the entire year, and they are relatively easy to collect and to identify.

The diagrams at this website show the types of invertebrate species that indicate good water quality (intolerant species) and those that indicate poorer water quality (tolerant species). Some organisms exist in both situations and are not indicator species.

http://www4.ncsu.edu/~ajclevel/Ident.html

Flow Rate-In order to measure the flow rate of the river, we toss a colorful, floating, biodegradable object into the midstream of the river and measure the time it takes to travel 100 meters downstream. To do this, a 100-meter line is stretched along the bank of the river and a student records the time a tomato or apple is tossed into the river upstream and the time it has passes the end of the 100-meter line. This is a rough measure of the flow rate at the surface of the river. By selecting something that is small and floats partially submerged, we have reduced the effect of the influence of air or wind.

The United States Geological Survey uses a gage to provide a more accurate and continuous record of the flow rate of the Olentangy River. The gaging station is located north of Rt. 161, at the Wilson-Bridge location on the sampling sites map. Data from the USGS gaging station provide a record of monthly, seasonal, and annual changes in the river.

Temperature change-The temperature of the water is taken according to the GLOBE protocol. A sample of river water is obtained by lowering a bucket into the river and pulling it up to the study area. The thermometer (in a metal housing) is submerged into the bucket and allowed to stabilize over a 3 minute timeframe. The bulb of the thermometer remains submerged while it is read by 3 different students. The average of the three temperatures is recorded.