Watersheds, River Hydrology, & Fish Passages

Question 1

Watershed

Answer 1

An area drained by a specific river system (called a drainage basin) that acts like a funnel by collecting all the water within the area by the basin and channeling a waterway

Question 2

Watershed Boundary

Answer 2

Geographical barriers that separate each drainage basin from adjacent basins

Question 3

How are watersheds organized?

Answer 3

By stream order

Question 4

Stream order

Answer 4

How watersheds drain water to an elevation

- 2.4 to 1 stream order bifurcation; for every large stream there are 2.4 smaller ones.

Question 5

Stream order bifurcation

Answer 5

2.4 to 1

Question 6

How does surface water flow?

Answer 6

Meanders both laterally and vertically

- Stream water does a 1/2 turn at every meander bend

Question 7

How are meander scars and oxbow lakes created?

Answer 7

When meander bends break through to form a new channel

Question 8

Meanders

Answer 8

Bends in the land along rivers caused by water erosion

Question 9

How do healthy rivers differ from unhealthy rivers?

Answer 9

• Healthy rivers have stable banks protected by riparian buffer zones, bent trees that hang over streams, and water moves slow.
• Unhealthy rivers have little to no riparian buffer zones, banks that migrate fast, and water moves fast.

Question 10

What issues are caused by culverts?

Answer 10

Perched culverts can create a distance too high/far for fish to jump or they create velocity barriers.
- Improperly placed road culverts block upstream passage

Question 11

List the different types of fish ladders discussed in class

Answer 11

1. Pool and Weir
2. Pool and Orfice
3. Baffle Fishway: Denil
4. Rock Ramp Fishway
5. Fish Elevator
6. Siphon Fishway

Question 12

What is a natural solution for perched culverts?

Answer 12

Riffle building: properly placing granular substrates (rocks) to help raise the water level

Question 13

Pool and Weir Fish Ladder

Answer 13

Consist of a series of partitions or weirs installed at intervals down a channel. They can extend the full width of the channel but are most commonly notched. Water flows overtop weirs, and each is slightly lower than the next, which creates step like pools.
- Best for areas where water flow remains fairly constant

Question 14

Vertical Slot

Answer 14

Fishway that consists of vertical baffles installed in intervals along a channel to create pools.

• Still need a short burst of energy in between slots
• Can handle variation in water levels

Question 15

Baffle Fishway

Answer 15

Fish ladder with baffles on the floor and sides of a rectangular structure

Question 16

Fish Elevator

Answer 16

Fish are lifted by water-filled chambers

Question 17

Denil Fish Ladder

Answer 17

Baffles are installed along the floor and sides of the flume, creating a narrow zone of reduced water flow.
- Best suited for small streams