1.7 Variable Buffer Width

1.7a

Buffers may have a fixed width where uniform runoff occurs (A). However, runoff is often non-uniform and flow is either diverging or converging due to topography, tillage practices, and other factors (B). A fixed-width buffer will be less effective in these situations.tc "Buffers may have a fixed width where uniform runoff occurs (A). However, runoff is often non-uniform and flow is either diverging or converging due to topography, tillage practices, and other factors (B). A fixed-width buffer will be less effective in these situations.

Instead, buffer width should be variable by widening and narrowing the buffer as runoff loads and buffer site conditions vary.

1.7b

Runoff areas and corresponding buffer locations to which they flow can be mapped (C). Buffer width can then be modified to account for differences in runoff loads (D). Buffers will need to be wider for upslope runoff areas that are larger and contribute greater loads.tc "Runoff areas and corresponding buffer locations to which they flow can be mapped (C). Buffer width can then be modified to account for differences in runoff loads (D). Buffers will need to be wider for upslope runoff areas that are larger and contribute greater loads.

The ratio of the upslope runoff area to buffer area can provide additional design guidance (see 1.8).

DOWNLOAD: 1.7 Guidelines and References (PDF)