Winter Road Sand In the Stream?
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Concepts:
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Sand applied to roads during the winter can enter water courses.
Areas close to the river and/or storm drains, road gradient, and dangerous intersections are all areas capable of supplying the most sand during runoff conditions.
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Objectives:
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To determine how much winter road sand may enter your stream
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Materials:
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Road map(s) of your stream or watershed (hopefully with a scale in feet). Paper, envelopes and stamps.
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Subject:
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Science and Language Arts
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Preparation and Procedure:
Have students write a letter to the town(s) or county highway department(s) requesting:
- the number of road miles maintained as all-season roads;
- the number of all-season road bridges over water courses;
- the number and location of storm water drains that empty directly into the stream or river,
- and the estimated amount of road footage drained by these storm drains;
- the average amount of sand applied to roads during a winter;
- a description of how (and where) the department cleans up winter sand (if they do).
On the road maps, students should highlight (and calculate number of feet and miles) for:
- any road area within 100-feet of a stream or river;
- road areas in excess of 100-feet of a stream if there is likelihood of runoff due to long hills, curves, or dangerous road intersections where sand is applied liberally;
- and all bridges over streams or river. (Students may apply a factor of an additional 20% to these feet/miles because they are more heavily sanded.)
From the two exercises above, students can determine the % of the total average winter sanding material that has a high potential for entering water courses during runoff events.
To determine which has the greatest potential for impact on the stream--road sand runoff or
streambank erosion--students can compare volume amounts from this exercise with volume
amounts gathered from "Streambank Erosion - Measuring Bank Loss"