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# Navigate a Watershed

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Learn how the physical and biological systems within watersheds work together to create a continuum of resilient, interconnected ecosystems. Move from watershed to river basin to cross sections of headwaters, streams and rivers for a look at the inner world of surface water using the tabs below the image.  Click on the blinking dots for more information.

This interactive is part of the Surface Water series.

### Pre-viewing Question

• What does a diverse community of aquatic organisms look like?

### Discussion Questions

• Tab 1: There are two continental divides in the U.S.  One divide sends rainwater and snowmelt towards the Atlantic and the Gulf of Mexico.  The other sends rainwater and snowmelt towards the Gulf of Mexico and the Pacific.  Can you determine by studying the map where these continental divides are located? How can you tell?
• Tab 2: What percentage of the U.S. population gets its drinking water from the Delaware River Watershed?
• Tab 3: Draw a diagram that explains the "stream ordering" system. Next, locate the stream nearest to your home or school on a map. What order of stream do you think it is?
• Tab 4: Examine the pattern of waterways in the Brandywine Basin.  Does the pattern remind you of any other patterns in nature?  Which ones?  How are they similar?
• Tab 5: Use the stream order chart to calculate how much of the Brandywine’s total stream miles are headwaters (stream orders 1 and 2).
• Tab 6: Use the stream order chart to calculate how much of the Brandywine’s total stream miles are mid-sized streams (stream orders 3 and 4).
• Tab 7: Use the stream order chart to find how much of the Brandywine’s total stream miles are river (stream orders 5+).
• Refer to tabs 8, 11 and 14 to answer these questions about the Brandywine's headwaters, mid-sized streams, and river.
• How does the amount of sunlight available compare?
• How do the widths, depths and slopes compare?
• How do the rock size and sediment found at the bottom differ?
• How do the plants found next to the headwaters, mid-sized streams and river support life within the water?
• How does the habitat for fish compare?
• How are width, depth, slope and rock size interconnected in each part of the stream system?
• Refer to tabs 9, 12 and 15 to answer these questions about the Brandywine's headwaters, mid-sized streams, and river.
• How does the abundance and variety of algae compare?
• What roles do wood debris and falling leaves play in the headwaters, mid-sized streams and river?
• What roles do bacteria, fungi and detritus have in the stream ecosystem?
• What are the preferred food sources of shredders, collectors and grazers?
• What is the difference between a collector-gatherer and a collector-filterer?
• Refer to tabs 10, 13 and 16 to answer these questions about the Brandywine's headwaters, mid-sized streams, and river.
• Which insects depicted have the shortest life and the longest life spans?
• What are some strategies predators use to find their prey?
• What would happen to the fish and birds if the water were too polluted to support a diverse community of aquatic organisms?
• Count the ratio of shredders/collectors/grazers/predators in each cross section.  How do the ratios change as you move downstream?

### Follow-up Questions

• Can you now describe what a diverse community of aquatic organisms looks like?
• There is evidence to suggest that the ratios of functional feeding groups that you found in this interactive holds true for the majority of headwaters, mid-sized streams, and rivers in the Piedmont region of the United States. The River Continuum theory describes this dynamic equilibrium, giving us a conceptual model to guide our efforts to repair and restore degraded rivers. How would the River Continuum concept inform your ability to evaluate any plans for Piedmont stream restoration?