Evaluation of Cross Vanes as a Stream Restoration Measure, Batavia Kill, Catskill Mountains, New York
Abstract
A Natural Channel Design (NCD) stream restoration effort incorporates a number of components to improve stream stability, including cross vanes. Cross vanes are rock structures placed in the stream channel designed to maintain stable channel width and depth. An arm, constructed of boulders, extends upstream at bankfull from each bank. The arms are joined by a sill, constructed of boulders, perpendicular to the direction of flow. Design specifications state that the angle of the arm with the adjacent bank should be 20-30 degrees and the arm slope should be 3-7 degrees. Also, each arm and the sill should each occupy 1/3 of the width of the channel. Downstream from the vane is a scour pool. While the design and placement of cross vanes are based on hydraulic considerations, a secondary goal is that they will also improve aquatic habitat and likewise aquatic biodiversity. Even though cross vanes have design specifications, in practice it has been found that the structures fall along a spectrum. Additionally, it has been observed that the downstream scour pool dimensions vary, which may be an early indicator cross vane failure. As part of a stream restoration project twelve cross vanes were constructed along a 3400-foot reach of the Batavia Kill, located in the Catskill Mountains, in Greene County, New York. In order to conduct a post-construction assessment of cross vanes extensive physical surveys of each structure were conducted. Along with the survey data, hydrologic data for the site was obtained, bank erosion hazard data was recorded and macroinvertebrates were collected downstream from the cross vanes. Lastly, an evaluation of this data was conducted to better understand the relationship with scour pool depth.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2005
- Bibcode:
- 2005AGUSMNB33E..01S
- Keywords:
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- 1824 Geomorphology (1625);
- 1860 Runoff and streamflow;
- 1871 Surface water quality