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RESOLUTION R-1718-21: A RESOLUTION OF THE COUNCIL OF THE CITY OF NORMAN, OKLAHOMA, ACCEPTING THE LOWER IMHOFF CREEK STUDY FINAL REPORT.
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BACKGROUND: A Storm Water Master Plan (SWMP) was developed for the City of Norman by PBS&J and accepted by City Council in November 2009. Among other things, this plan delineated the various watersheds in the City, identified stream segments which needed restoration and improvement, and identified projects to provide this restoration including conceptual designs. One such stream segment in need of restoration is Lower Imhoff Creek between Lindsey Street and Imhoff Creek’s confluence with the Canadian River south of State Highway 9.
In the Storm Water Master Plan, Lower Imhoff Creek is divided into two problem areas, or reaches, IC-1 and IC-2. IC-1 is that portion of Imhoff Creek between State Highway 9 and its confluence with the Canadian River. IC-2 is that portion of Imhoff Creek between State Highway 9 and a point some 2,000 linear feet north of Imhoff Road. The SWMP recommends design and installation of stream bank stabilization techniques along stream segments IC-1 and IC-2. The problem identified for IC-1 is “800 LF of severe bank erosion along both banks downstream of Highway 9. The erosion along the banks has caused trees to fall into the creek”. The identified problem in the SWMP for IC-2 is “4,200 LF of severe bank erosion along both banks beginning at the upstream face of Highway 9 to approximately 2,000 LF upstream of Imhoff Rd. The erosion along the banks has caused property fences and trees to fall into the creek.” IC-2 is the focus of the current project.
In an effort to address the stream bank erosion occurring along the portion of Imhoff Creek identified as IC-2, a project was proposed by City staff and discussed by Council for a preliminary stream study as part of the FYE 2015 Capital Budget process. Council approved an allocation of $200,000 in the FYE 2015 Capital Budget for this project. The objective of this project is to provide conceptual engineering design and recommended phasing of stream improvements for IC-2. These conceptual designs and priority recommendations will be used to perform engineering design and construction plans for the identified stream improvements.
On January 15, 2015, City staff published a request for proposal to solicit engineering services including the hydrology of Lower Imhoff Creek and the hydraulics of flow through the creek channel. The City received 12 proposals for this service.
The selection committee included three (3) staff members consisting of Scott Sturtz, City Engineer; Joe Willingham, Stormwater Engineer; Todd McLellan, Development Engineer; and two (2) private citizens including David Dary, Retired Professor Emeritus of the OU School of Journalism and resident of Lower Imhoff Creek, and Asha Prather, PhD, resident of Norman, who independently scored each proposal on a point scale as defined in the request for proposal. Upon review of the proposals by the selection committee, four firms were selected for interviews. After the interview process, Meshek and Associates of Tulsa, Oklahoma, was selected as the firm most qualified to provide the engineering services.
On June 9, 2015, City Council approved Contract No. K-1415-134 for $143,000.00 with Meshek and Associates. The contract services included:
• Kickoff Meeting and Channel Walk
• Data Collection and Processing
• Easement and Right-of-Way Evaluation
• Hydrology and Hydraulic Modeling
• Ecological Inventory
• Development of Stream Restoration Alternatives and Recommendations
• Council and Public Meetings
• Surveying and Geotechnical Investigations
On June 30, 2017, Meshek and Associates submitted the Lower Imhoff Creek Study Final Report which is included as Exhibit A to the resolution). On July 11, 2017, City staff and Brandon Claborn, Principal Engineer for Meshek and Associates, presented the findings of this report to City Council.
DISCUSSION: The Lower Imhoff Creek Study Final Report recommends several preventative and mitigation recommendations based on the data gathered during this study as follows:
• Implementation of a 5-year Monitoring Plan to evaluate the rate of degradation to channel;
• Provide training to City maintenance staff to learn new techniques for maintaining more natural stream restoration devices such as gabion walls, cross vanes, and others;
• Design and construct stream mitigation improvements in two phases:
1. Phase 1 will begin at Imhoff Road and end approximately 1200 feet downstream of Imhoff Road. This section should be addressed first due to the risk to existing infrastructure. Estimated cost is $3,150,300.00.
2. Phase 2 will begin upstream of Imhoff Road and end at the end of the improved channel. Estimated cost is $4,347,950.00
By this resolution, City Council accepts the submission of the Lower Imhoff Creek Study Final Report by Meshek and Associates, Inc.
RECOMMENDATION: Staff recommends approval of Resolution R-1718-21, accepting the Lower Imhoff Creek Study Final Report by Meshek and Associates, Inc.