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BANK STABILIZATION |
| Bank stabilization techniques are used to prevent erosion, undermining, and eventual collapse of banks. These techniques typically involve lining the banks with materials ranging from rock-filled wire baskets (called "gabions") or sacked concrete to old tires or other debris. |
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Gabions |
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Sacked concrete |
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Tires |
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A vertical bank along San Francisquito Creek |
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Creek bank erosion is a natural process, allowing creeks to gradually change course over time. However, when erosion threatens roads, buildings, and other infrastructure, property owners often seek to protect their property by hardening the banks. Attempting to constrain the creek in its current alignment can result in vertical banks that are vulnerable to collapse and too steep to support riparian vegetation. |
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IN-CHANNEL BARRIERS |
| Structures built within the channel, such as dams, culverts, and fences, make it difficult for migrating fish to reach the upper tributaries where they return each year to spawn. Although San Francisquito Creek dries up in the summer, the tributaries have year-round pools with cool, well-oxygenated water with generally low levels of pollutants, and a gravel creekbed that steelhead need for spawning. |
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Instream barriers make it difficult for fish to migrate upstream |
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