1. Power of a Rain drop

2. interaction of water with soil 2/3rds of the riparian story
Vegetation

3. Dissipation of energy of accumulated raindrops (deposition and erosion)

4. Meander is an energy dissipation strategy
Meandering of Gulf Stream in Atlantic

5. Rivers will be crooked
Walla Walla River, 1964

6. Lesson 1 creeks will meander
Creeks do not want to be wide and straight

7. Meander and gradient Hill Hill Hill Hill Elev 1500
Channel Length 25,000 ft
Gradient 0.4%
Gradient 1.0%
Channel Length 14,000 ft
Gradient 0.7%
Hill
Hill
Valley Length: 10,000 ft
Elev

8. Channels design themselves to manage the energy/water and sediment delivered them in most efficient manner

9. Floodplains Dissipate Energy and Trap Sediment
(#)
Floodplains Dissipate Energy and Trap Sediment
Above Bank full is Floodflow
Everything above is active floodplain. (Active, not 100 yr.)
During Flood flow a high energy moves the sediment through the system,
but low energy in the floodplain to capture some of the sediment.
Really two columns of water at work. Flood plain is a pressure relief valve of the channel
Low velocity water
Active Floodplain
High velocity water

10. Floodplain

11. Flooding Recharges Water Tables
(#)
Flooding Recharges Water Tables
Important to note that the water table and the water in the creek is the SAME WATER.
At base flow the water table is contributing to the creek.
In flood flow the creek is contributing to the water table.
Water Table

12. Excessive Energy (Erosion) Enlarges the Channel
(#)
Excessive Energy (Erosion) Enlarges the Channel
Here is the channel that has designed itself over time to drain the landscape, carry appropriate volume and velocity of flood waters and move the sediment produced within that system.
More runoff than the system was designed to handle and or vegetation component has been impaired.
This is what can happen when energy of floodwater exceeds the strength of poorly vegetated banks.

13. Lane’s Relationship, 1950 without vegetation

14. Enlarged channel

15. Down-cutting Drains the Water Table
(#)
Down-cutting Drains the Water Table
Downcutting reduces the water table and bank storage, amounts to drying out the riparian system.
There is a permanent loss of the water table when down cutting occurs.

16. Down-cutting: Loose Access to Floodplain
(#)
Down-cutting: Loose Access to Floodplain
Bankfull flow well below floodplain
Original channel at bank full
That same volume of water that used to access the floodplain no longer gets out
It has no way to dissipate its energy, so all that energy is banging against the sides and bottom of the channel.

17. Loss of floodplain

18. Where does flow come from during dry times?
(#)
Where does flow come from during dry times?
Water Table
Riparian Sponge
Rock Layer
Creeks in the headwater region operate in a similar fashion even though they are confined by a rock layer.
Headwater Stream

19. The Water Table Sustains Base Flow
(#)
The Water Table Sustains Base Flow
Maintenance of base flow is especially dependent on the water table

20. Riparian Sponge

21. Channel Widening Reduces the Riparian Sponge
(#)
Channel Widening Reduces the Riparian Sponge
Process of channel erosion (caused by inadequate vegetation) is different in rock bottom channels. Loss of water storage.
HOW MUCH RIPARIAN SPONGE HAS BEEN LOST/ all that left is this tiny little sponge.

22. Loss of sponge in headwater streams means reduced base flows

23. Overly Wide Channels Reduce Sediment Transport Ability
(#)
Overly Wide Channels Reduce Sediment Transport Ability
Still a base flow (only a few inches deep) and still a bankfull flow, but no bona fide channel where the energy is high enough to transport sediment. This is why many headwater creeks have massive gravel deposits that accumulate and move from place to place and never seem to get stabilized. The channel cannot decide where it wants to be.

24. Sediment can not be efficiently transport

25. Degraded and eroded channels can be restored
(#)
Degraded and eroded channels can be restored
The good news is that both channel types can repair themselves according to the natural processes of channel restoration The essential thing is the presence of at least some stabilizing vegetation to start the process.
Channel
Flood Plain
Water table All at a reduced elevation
Natural Channel Restoration

26. Dissipating Energy and Catching Sediment
(#)
Dissipating Energy and Catching Sediment

27. Function will return at a new elevation.
(#)
Function will return at a new elevation.

28. Early Signs that recover is occurring

29. (#)

30. Recovery can start with one plant.

31. Sponge can be built by the creek on top of bedrock

32. Recovery occurs without intervention once hindrances are removed
2007
06 PFC Erosion/Deposition Items
1_18_2008
Recovery occurs without intervention once hindrances are removed
2008
Nueces River
2011
2010 32

33. (#)
Burro Creek 1981
Burro Creek
2000

34. With new understanding you can see what is missing

35. Recovery Potential for pastures is widely accepted and understood

36. Why not riparian recovery?

37. Starts energy dissipation usually a plant