1. Sediment delivery
source: dingdarling.org

2. SD premise
Sediment yields inferred from suspended load measured in streams often doesn’t match model predictions of soil loss from the uplands.

3. Sediment Delivery Ratio (SDR) 𝑆𝐷𝑅= 𝑦𝑖𝑒𝑙𝑑 𝑙𝑜𝑠𝑠
Graphic: naturalcapitalproject.org

4. 𝑺𝑫𝑹∝𝑳𝒐𝒈(𝑨)
According to a log-linear regression on a large dataset, the SDR declines as a function of upstream watershed area. (USDA)

5. SDR
SDR depends on the timescale and spatial scale used to estimate/measure losses and yields.

6. What’s wrong with SD?
Discuss…

7. Gully control/mitigation
PREY
Gully erosion is 2 processes:
Hydraulic erosion
Mass wasting
Gully erosion is (at least) 2 problems:
Soil loss
Downstream sediment loading

8. 1. Divert runoff (R,E)
Convey runoff through alternate, stabilized flowpath.

9. 2. Headcut stabilization (E)
Weirs and grade-control or drop-structures most common

10. Grade control & drop structures (E)
Weirs and drop structures can stabilize headcuts

11. 3. Check dams (E,Y)
Check dams must be in series along gully floor

12. Wood check dam

13. Log check dams
Solution can be suited to available material, desired aesthetic

14. Brush check dam
Suitable forsmaller gullies

15. Straw bale check dams

16. Temporary check dams (soil berms, coir logs)
Not a long-term solution