Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Adobe Upper Reach 5 Conceptual Plan Issues December 9, 2003 Workshop

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Modeling of Flows At minimum, provide capacity to convey what flows under W. Edith Ave. Bridge Downstream of W. Edith Ave. Bridge: –Accommodate Flows A, B1, and B2 –Partially accommodate Flows A, B1, B2 and allow for overland flow on Rogez/Astiz property parallel to creek

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Top of Bank Boundaries Before moving forward, there must be agreement on allowable top-of-bank margin for proposed project –Line 1 – twice width of existing creek –Line 2 – matches width of creek d/s of Robleda Drain –Line 3 – Swansons 1% top-of-bank

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Top-of-Bank Boundaries (contd) Middle line seems to be good working top- of-bank target Can land between Line 2 and Line 3 be potentially used for mitigation planting?

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Width of Creek Channel Upper Reach 5 should not be wider than lower Reach 5, within limits of good channel design Can creek be made deeper to minimize channel width w/out compromising downstream and upstream portions or acceptable creek design?

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Channel Relocation Removal of oxbow near Theis property is OK Creek channel can be moved 5-10 feet toward LAH side if needed to protect trees on Los Altos side

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Banks ACWG proposal includes gabion or rock rip rap for creek banks to minimize channel width Regulatory agencies may have issues with these options and may require mitigation for installing such hardscape

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Mitigation Mitigation may be required for: –Adding hardscape to channel –Loss of riparian habitat along top-of-bank due to channel widening Ratio of mitigation varies based on value of lost habitat Mitigation ratios? 1:1, 2:1, 3:1

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Mitigation (contd) Regulatory agencies prefer mitigation to be done at site of impacts District has strong interest in mitigating for impacts on site Minimize channel width and use portions of Rogez/Astiz properties for mitigation plantings

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Transplanting Trees District will evaluate this work In the interest of cost-efficiency, this criterion may be difficult to achieve

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Proposed Conceptual Approach Detailed hydrology to determine Flows A, B1, and B2 Assume rock rip rap or gabion banks with slopes of 1:1 or 1.5:1 Develop appropriate channel bottom slope –Match existing downstream invert and desired invert under W. Edith Bridge –Drop structures to allow for fish passage

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Proposed Conceptual Approach (contd) Determine minimum width of channel to convey flow (A) coming under W. Edith Bridge Determine minimum width of channel to convey portion or all of overland flows B1 and B2

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting Proposed Conceptual Approach (contd) Follow CEQA process to determine impacts of project and develop mitigation proposal Maintain continual interaction with ACWG and City/Town while developing alternatives

Presentation Developed Prior to Input From 12/17/03 Adobe Collaborative Meeting NEXT STEPS Draft Proposed Project Plan (PPP) – January 28, 2004 Review, discuss, modify PPP – February 23, 2004 Prepare for District Board consideration – March 2004 Present PPP to Board – April 6,2004 Incorporate into Capital Improvement Program