Table 1 Mean net deposition (ΔZ) and SS retention efficiency (Reff) of the different parts of the 820 m long two-stage channel during periods t = 0‒2 yrs, t = 2‒9 yrs, and the entire 9-year period (standard deviation of the 6 cross-sections in parentheses). Negative values denote net erosion. The 9-year average values do not correspond exactly to the temporal average over the two periods because of differences in the cross-sectional geometry in different yeas. FP refers to floodplain, MC to main channel. Detailed floodplain flow properties are given in supplementary text S2 and table S2 online.
From: Evaluating multiannual sedimentary nutrient retention in agricultural two-stage channels
Channel part | ΔZ in t = 0‒2 yrs (higher QFP) (cm/a) | ΔZ in t = 2‒9 yrs (lower QFP) (cm/a) | ΔZ at t = 0‒9 yrs (cm/a) | Reff at t = 0‒2 yrs (%) | Reff at t = 2‒9 yrs (%) | Reff at t = 0‒9 yrs (%) |
|---|---|---|---|---|---|---|
Floodplain bank | 0.1 (0.5) | 0.1 (0.1) | 0.1 (0.2) | 0.5 | 1.0 | 0.9 |
Floodplain | 0.7 (0.5) | 0.1 (0.1) | 0.3 (0.1) | 11.0 | 2.5 | 4.7 |
MC‒FP bank | −0.8 (0.6) | −0.4 (0.9) | −0.3 (0.6) | −2.9 | −1.1 | −0.9 |
Main channel bed | −2.6 (2.0) | −1.6 (1.1) | −1.7 (0.7) | −9.3 | −6.7 | −7.2 |
MC bank below FP level | −0.2 (3.5) | −0.9 (0.9) | −0.5 (1.1) | 1.2 | −2.2 | −1.0 |
MC bank above FP level | 0.7 (1.7) | −1.3 (0.5) | −0.8 (0.4) | 1.2 | −8.5 | −5.1 |
Cross-sectional average | 0.0 (0.4) | −0.2 (0.2) | −0.2 (0.2) | 0.2 | −10.3 | −8.6 |
Cross-sectional average excluding large erosion on steep banks | 0.0 (0.1) | −0.1 (0.1) | −0.1 (0.1) | 3.4 | −6.6 | −4.8 |
