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Final Concept Report

Strand Final Concept Report

At the June 7 2016 Regular Meeting, Strand Associates presented their Final Concept Report on the Stormwater Alternatives Study to the Village Council. Strand Associates was hired by the Village last fall to re-evaluate the Village’s western drainage basins for creative, cost-effective stormwater improvements for the 100-year event. Strand has been assessing a host of traditional and emerging stormwater management technologies which conform to the Village’s flood control objectives.

After completing an evaluation of watershed data (including topography, density of development, impervious ground cover and soil conditions, frequency and extent of flooding, neighborhood character, and plans for improvements or changes in the watershed), Strand identified a number of potential stormwater management and flood control opportunities.

Strand has carefully considered the feasibility, practicality, cost, benefit, and measure of protection of each opportunity, and proposes a combination of projects that produce a desirable balance of flood reduction, cost-effectiveness, and phased implementation. This series of projects, if fully implemented, would significantly reduce the number of homes in the watershed that are at risk of flooding during the design event. The proposed four-phase Vision consists of 15 discrete stormwater storage and conveyance projects, water quality management improvements, and distributed green infrastructure improvements. The current Stormwater Vision is shown in the following figure:


Partnerships with other community agencies in the watershed will be integral to successful and sustainable stormwater and flood mitigation improvements.  Strand is exploring collaborative opportunities with stakeholders whose goals and objectives are directly impacted by stormwater issues, and who will also benefit from the Village’s stormwater management efforts. Strand has also conducted an extensive public participation effort to gain valuable input from the community about how its needs, desires, and opportunities are addressed by the identified alternatives. The estimated cost to implement all four phases, including engineering and necessary contingencies, is $57,717,000 in current dollars:

  • Phase 1 Total: $23,578,000
  • Phase 2 Total: $16,380,000
  • Phase 3 Total: $4,675,000
  • Phase 4 Total: $13,084,000

As the Council continues its discussion of the Stormwater Vision, it will be gathering input from citizens, public agencies integral to the Vision, and other interested parties.  The Village anticipates continued, broad community conversation on phasing, funding, and implementation steps.

The full agenda materials, as reviewed at the June 7 Council meeting, are included below.

Click here to see the June 7 Strand Associates' PowerPoint Presentation.

Stormwater Alternatives Study for Western and Southwestern Winnetka

Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Appendix G
Appendix H
Appendix I
Appendix J

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