Venturing STEM exploration in that field. You should be prepared to discuss the role of water in the area or field you’ve chosen. (If you have already completed a Venturing STEM exploration in one of these fields, please choose a different field for this award.)
The Polar Literacy Initiative (https://polar-ice.org/polar-literacy-initiative/) is a good place to start investigating these topics.
Oil spills can be remediated in four ways: physically skimming the oil off the surface of the water, burning the oil, using surfactants to break the oil slick down, or doing nothing and letting nature take care of it.
A surfactant is a material that lowers surface tension between two liquids, breaking down the barrier between them. They are used in detergents, dispersants, wetting agents, medicine, and so on.
See
Explainer: why are chemical dispersants used in oil spills?
https://www.chemistryworld.com/news/explainer-why-are-chemical-dispersants-used-in-oil-spills/1017322.article
Oil Spill Dispersants: Efficacy and Effects (2005)
https://www.nap.edu/catalog/11283/oil-spill-dispersants-efficacy-and-effects
One activity could be having scouts try different tools to skim the oil using different tools – a paper towel, wood splint, steel wool, cotton balls, and so on. You could also have them build a physical oil skimmer. Which one collects the most oil and least water?
Another activity could be putting oil and water into a sealed scintillation (or other clear) vial and shaking vigorously. What happens? Then add one drop of dishwashing liquid (Dawn works best) and shake again. What happens this time?
Your state department of conservation or natural resources can be a great place to start.
Flyover Country® is a National Science Foundation funded offline mobile app for geoscience outreach and data discovery. https://flyovercountry.io/
Useful Links
USGS web sites https://water.usgs.gov/edu/watershed.html , and https://water.usgs.gov/edu/runoff.html
US EPA's Surf your Watershed https://www.epa.gov/waterdata/surf-your-watershed
USGS Watershed Tool at https://viewer.nationalmap.gov/advanced-viewer/ . Turn on the National Hydrography Dataset (NHD) in the Layers list, and the topographical lines will show where water flows. Turn on the Watershed Boundary Dataset in the Layers list, and you can see how large of an area your watershed covers, and other watersheds that are nearby.
Watershed - a geographic area that drains into a common outflow point, which could be a river basin.
Runoff - That part of the precipitation, snow melt, or irrigation water that appears in surface streams, rivers, drains or sewers. It may be described by how fast it appears, or by source.
Runoff coefficient - a dimensionless coefficient that describes the amount of precipitation that runs off an area, as opposed to being absorbed into the ground. It ranges from 0 to 1, with larger values for areas with pavement and steep gradients (roofs range from 0.75 to 0.95), and lower for permeable, well-vegetated areas such as forests and flat lands (woodlands can range from 0.05 to 0.25). A composite runoff coefficient is one that covers an area made up of multiple types of surfaces – for example, a lot that is ½ pavement and ½ asphalt would have a composite coefficient that was proportional to the amount of each surface area.
Infiltration – rainfall or other water that is absorbed into the soil
Point source pollution - water pollution coming from a single identifiable point, such as a sewage-outflow pipe
Non-point source pollution – pollution collected as water washes off a large area. Could include pesticides, soil particles, and so on.
Oceanic dead zones – a low-oxygen area (hypoxic), often found near the mouth of rivers, resulting from "excessive nutrient pollution from human activities coupled with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water. (National Oceanic and Atmospheric Administration)"
Example: If the watershed you selected is 10 acres, that is 6.273 x 107 sq in. A 1 inch per hour rainfall will deposit:
6.273 x 107 sq in * 1 in/hr. * 1 hour = 6.273 x 107 cubic inches of rain per hour
6.273 x 107 cubic inches of rain/hr. * 1hr/60 minutes = 1,045,500 cubic inches of rain/minute
1,045,500 cubic inches of rain/minute * 0.004329 gallons/cubic inch = 4520 gallons rain/minute
To put that into perspective, an average American shower uses 17 gallons of water, which is 270 showers worth of water falling every minute over the watershed.
Type | Runoff Coefficient | % of water that runs off |
---|---|---|
Drives, Walks, Roofs | 0.90 | 90% |
Lawns, 50% grass | 0.10 | 10% |
Lawns, 75% or more grass | 0.05 | 5% |
Street, paved | 0.90 | 90% |
Streets, gravel | 0.25 | 25% |
Sample Calculation:
If your property is 1 acre, that is 6.273 x 106 sq in.
A 1 inch per hour rainfall will deposit:
6.273 x 106 sq in * 1 in/hr * 1 hour = 6.273 x 106 cubic inches of rain per hour
6.273 x 106 cubic inches of rain/hr. * 1hr/60 minutes = 104,550 cubic inches of rain/minute
If half the property is house (i.e., roof), and half the property is a grass lawn, the amount of runoff would be:
Runoff = (1/20.90 + ½0.05)*104,550 in3/minute = 49,661 in3/minute
This is the Rational Method for runoff calculations, and is a quick, simple calculation. Much more sophisticated models and computer algorithms are also available.
Helpful Resources:
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