Title
Consider and take action on a resolution authorizing a professional services agreement with Kimley-Horn and Associates, Inc. (K-H) for design work related to the Clear Creek Tributaries Select Clearing and Desnagging Project (DR1910) in an amount not to exceed $362,900 (Director of Engineering)
Background:
Approval of this resolution will authorize the City Manager to enter into an agreement with K-H to design drainage improvements along Magnolia Creek, Cedar Gully, Landing Ditch, and Newport Ditch for an amount not to exceed $362,900.
In March 2019, a channel capacity analysis for League City was conducted by K-H. The study reviewed the following portions of four (4) Clear Creek tributaries:
? Cedar Gully from Clear Creek to FM 518 (DR1910A)
? Landing Ditch from Clear Creek to FM 518 (DR1910B)
? Newport Ditch from Landing Ditch to FM 518 (DR1910C)
? Magnolia Creek from Clear Creek to FM 518 (DR1910D)
This analysis confirmed that by removing vegetation within the channel banks of the selected areas, these tributaries would see a significant increase in their overall channel capacity:
1. The 4,200 LF section of Cedar Gully will see a 38% increase (from 2,321 cfs to 3,095 cfs)
2. The 760 LF section of Landing Ditch will see a 34% increase (from 2,908 cfs to 3,873 cfs)
3. The 5,600 LF section of Newport Ditch will see a 56% increase (from 2,715 cfs to 4,210 cfs)
4. The 8,400 LF section of Magnolia Creek will see a 53% increase (from 1,555 cfs to 2,204 cfs)
This project would allow for more channel capacity while addressing some existing erosion issues which could mean removal of dead and diseased trees and trees within the channel/channel banks or near the top of bank (if there is risk of falling), and/or limited correction of the channel’s cross-section to a more uniform earthen pattern....
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