Comparison of Two Potential Streamgage Locations on Scott Creek at Swanton Pacific Ranch, California

<p>Two locations on Scott Creek, located 12 miles north of Santa Cruz California, are being considered for the installation of a streamgage to measure discharge. Each location offers unique considerations and challenges in gage construction and discharge measurement capabilities. A detailed flood frequency analysis was completed using a direct watershed comparison, direct equations developed by Waananen and Crippen, a Log Pearson Type III Frequency Distribution, a regional analysis, and two-station comparisons. Final results indicate a 100-year recurrence interval of 6,310 ft3/s at the Upper Scott Creek location and 6,520 ft3/s at the lower location. A detailed indirect measurement revealed that the Lower Scott Creek gage location can only maintain a discharge of 2,500 ft3/s, or a 10-year frequency event, before bank overflow. Therefore, a cableway spanning the width of the design flow cannot be constructed and stage readings at extreme peak events will not accurately represent the true hydrograph. A bridge at the Upper Scott Creek gage location will provide a means for measuring high flow events; however, the channel is in a state of disequilibrium due to debris jams within the 140 foot reach above the bridge. This site is also problematic due to the occurrence of channel avulsion which is scouring and incising a new channel which threatens to undermine the left bank wingwall of the bridge. Remediation measures have been proposed, including the installation of a cross-vane and wing-deflectors, to mitigate negative effects of erosion and reestablish a natural channel condition. The upstream location has been selected as the preferred alternative given the remediation measures are successful.</p>

Name thesis:degree_name

MS in Forestry Sciences

Discipline thesis:degree_discipline

Natural Resources Management

Year dc:date.available

2010

Author dc:creator

• Scrudato, Matthew C.

Contributors dc:contributor

• Brian Dietterick
• Natural Resources Management
• College of Agriculture, Food, and Environmental Sciences

• Scott Creek
• Scotts Creek
• flood frequency
• indirect measurement
• streamgage
• instream structure
• spr_stu
• Natural Resources Management and Policy
• Other Earth Sciences
• Other Environmental Sciences

Identifier

10.15368/theses.2010.99

OAI identifier oai:identifier

oai:digitalcommons.calpoly.edu:theses-1345