NENANA RIVER PROJECT: Freshwater Sampling Protocol DRAFT
Freshwater Quality Protocols
Purpose
To monitor seasonal variation in water quality - suspended sediment load (SSL) and total dissolved solids (TDS) - in the Nenana River during the open water season (spring to fall) by obtaining and analyzing water samples.
Overview
Students and teachers will take water samples at diffent locations along the Nenana River, from near Cantwell in the mountains to Anderson in the lowlands. The SSL of the samples will be determined, and the TDS (salts, minerals, metals) will be measured. It is anticipated that these complementary water quality variables will vary in both space and time primarily in response to the seasonally-changing hydrology of the Nenana and Yanert glaciers (major water sources for the Nenana River), and deposition of sediments along the course of the Nenana River.
Background
During the winter, when air temperatures are below 0°C, the glaciers are frozen and contribute little to river flow. In the spring, as air temperatures increase, melting begins, initially at lower elevations and then at progressively higher elevations as spring and summer progress. First the snowcover on the glacier melts, and then, once the snow has melted, the glacier surface melts. The meltwater flows across the ice surface, often in deeply incised streams, which frequently disappear down moulins (holes, often large, in the ice), which feed into the internal plumbing system of the glacier. The internal plumbing system is, in turn, connected to the sub-glacial plumbing system at the glacier bed. Ultimately, the meltwater flows out of the glacier, typically at the front (sometimes called the snout) and feeds a river. In this case, the Nenana River and the Yanert River.
Glaciers shape the landscape by eroding the rock at their beds. The sediment that is created by erosion is carried away, either suspended or dissolved solid in the water that flows out of the glaciers. Because the glacier hydrological system (the plumbing) is subject to strong seasonal change, it is anticipated that SSl and TDS in the Nenana river will show strong seasonal variation. It is possible to capture this variation by taking water samples at regular intervals during spring, summer and fall.
Student Outcomes
Students will be able to:
· Observe the seasonal changes in the sediment load of a creek/river;
· Observe the changes in sediment load after the input of freshwater into the river (spring snowmelt and precipitation events);
· Communicate with other schools (within your watershed); and
· Compare the sediment loads at various sites along the river.
Science Concepts
Earth and Space Sciences
· The sun is the major source of energy for Earth surface processes.
· Weather changes from day to day and over the seasons.
· Water circulates through the crust, ocean and atmosphere
Geography
· Physical processes shape the patterns of the Earths surface
Scientific Inquiry Abilities
· Identify answerable questions
· Design and conduct scientific investigations
· Use appropriate mathematics to analyze data
· Recognize and analyze alternative explanations
· Communicate procedures, descriptions and predictions
Time
Reconnaissance and preparation of site: 30-60 minutes (not including travel time to and from the site)
Weekly and/or post-precipitation event visits: depending on the number of samples taken, about 10-15 minutes (not including travel time to and from the site)
Level
Upper elementary grades, middle school and high school.
Frequency
Observations will be made weekly at the same time of day ± 1 hour during the open water season.
It is also possible to sample multiple times during a single day at the same location to describe the daily SSL and TDS cycle.
It is also desirable to sample the river after precipitation events to determine the impact of additional runoff on the river’s SSL and TDS.
Samples could also be taken from non-glacier fed rivers and streams that flow into the Nenana River.
Material and Equipment
500 mL wide mouth Nalgene sampling bottles
Masking tape
Sharpie marker pen
250 mL graduated cylinder
Filter funnel
Filter paper
Digital balance
Liquid electrical conductivity meter (for measuring TDS)
Digital thermometer (for air and water temperatures)
Field work sheet
Environment observations work sheet
OPTIONAL – rubber boots or hip waders
Preparation
Select and mark the observation site.
Familiarize students with the water sampling and laboratory procedures.
Prerequistites
None
Water Sampling Site Selection
Students and teachers will collect water samples from the Nenana River at Windy (Cantwell), Denali Education Center, Healy and Anderson. The samples will be taken from free flowing water NOT standing water, and it is desirable to sample at approximately the same place each time.
While the Nenana River is dominated by water flowing from the Nenana and Yanert glaciers, not all tributaries are glacier-fed. Thus, analysis of samples obtained from tributaries would provide interesting data for comparison with data from the Nenana River.
Teacher Support
Advance Preparation
On the first visit to the site perform the GLOBE GIS protocol in order to establish the latitude, longitude and altitude of the sampling location. Alternatively, determine the latitude and longitude from a topographic map.
A kit containing all of the necessary materials and equipment for the sampling and laboratory measurements is provided by the project. A GPS unit is not provided.
Frequency of Observations
Water samples should be taken once per week, e.g., each Monday. This sampling frequency should be sufficient to catch the anticipated seasonal variation of SSL and TDS. However, there are additional factors that can affect SSL and TDS, and additional sampling strategies can be adopted.
For example, the glacier hydrological system responds not only to seasonal air temperature change, but also to daily air temperature change. As a consequence, the volume of water, SSL and TDS might be expected to change during the course of the day. Multiple daily sampling can reveal if such a diurnal SSL and TDS signal exists in the river. This kind of sampling scheme could be employed several times during the season, i.e., early spring (after snowmelt is complete), mid-summer, early fall and late fall (as the river begins to freze-up).
Additional sediment may also be introduced into the river during rapid freshwater input events. These include snowmelt in the spring and heavy rainfall events during spring, summer and fall. Sampling during and after these events (occasional sampling) provides valuable information about their effect on water quality.
Sampling Procedure
· Before a water sample is taken, label the sampling bottle lids using the masking tape and marker pen (Sharpie). The label should include the location (Anderson, Healy, DEC, Cantwell) and date (expressed as YY/MM/DD, e.g., 07/10/06). A sample number, e.g., #1, should also be included, even if only one sample is taken. If multiple samples are taken at the same location during the course of the day, number them according to the sequence they were sampled and also record the time that each sample was taken.
· Obtain a water sample from a free-flowing part of the river. Fill the 500 mL sampling bottle to nearly full. If sampling is to be done by walking part way into the water USE EXTREME CAUTION. Students should never enter the water unsupervised by an adult.
· Secure the lid tightly to the bottle once the sample is obtained.
· Measure the air and water temperatures; record the values.
· Complete the environmental observations work sheet.
· Return water samples to the classroom for analysis.
Measurement Procedure
· Shake the 500 mL sampling bottle to make sure that the sediment is evenly distributed throughout the water (depending on how long the sample has been in the bottle sediment may have begun to settle on the bottom of the bottle).
· Put the TDS probe in the agitated water sample and record the temperature and conductivity value shown by the meter.
· Agitate the water sample again, then pour the water into one of the graduated cylinders until the water level reaches the 250 mL mark. It doesn’t have to be exactly 250 mL because you will read the volume on the graduated scale and record the value.
· Fold a paper filter and place it in the filter funnel.
· Place the filter funnel and paper into the second 250 ml graduated cylinder.
· Carefully pour ALL of the water in the first 250 mL cylinder into the second
250 mL cylinder through the funnel and paper. This may take a few minutes, and it may be necessary to support the funnel so that the cylinder does not fall over.
· Remove the paper filter (with sediment) from the filter funnel, and set aside.
· Dry the filter paper and sample in a location where it will not be disturbed.
Once the sediment sample is completely dry:
· Set up the digital balance on a level surface. Calibrate if necessary. Make sure that the scale is set to grams. Do not use in a draughty place.
· Place a dry, unused paper filter on the balance, record its mass, then tare the scale.
· Weigh the dried sediment sample filter and sample and record its mass.
· Complete the data set.
Teacher Resources
About Glaciers
This richly illustrated Web site is the work of two well-known glaciologists and provides ample information on glaciers and their effects on the landscape. http://www.swisseduc.ch/glaciers/index-en.html Glacier hydrology is described and illustrated at http://www.swisseduc.ch/glaciers/earth_icy_planet/glaciers07-en.html
What is TDS?
This Web site provides a good description of total dissolved solids.
http://www.tdsmeter.com/print_abouttds.html
Water Quality
This U.S. Geological Survey Web site has a good primer on water quality.
http://ga.water.usgs.gov/edu/waterquality.html
GLOBE
GLOBE web site – Teacher’s Guide (http://www.globe.gov/tctg/tgtoc.jsp)
The GLOBE Teacher’s Guide, CD Version 2.0, 2005.
Freshwater Quality Protocols
Laboratory Data Sheet
Location: ______
Date: ______(YY/MM/DD)
Observer: ______
SAMPLE NAME:TOTAL DISSOLVED SOLIDS (CONDUCTIVITY)
Sample temperature °C:
Sample conductivity (mS):
Sample TDS (P):
SUSPENDED SEDIMENTS
Volume of water sample (L):
Weight of dry paper filter (mg):
Weight of dry sample and paper filter (mg)
Weight of dry sediment sample:
Total Suspended Solids (mg/L)
SAMPLE NAME:
TOTAL DISSOLVED SOLIDS (CONDUCTIVITY)
Sample temperature °C:
Sample conductivity (mS):
Sample TDS (P):
SUSPENDED SEDIMENTS
Volume of water sample (L):
Weight of dry paper filter (mg):
Weight of dry sample and paper filter (mg)
Weight of dry sediment sample:
Total Suspended Solids (mg/L)
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