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Title
Resolution adopting the City-Wide Drainage Master Plan for Cottonwood Creek
Presenter
Romin Khavari, City Engineer and Gabe Johnson, Stormwater Utility Manager and Floodplain Administrator
Recommended Action
approve
Analysis
Identifying and addressing drainage issues have been a priority for the City. In order to do so and to have a consistent approach, the City Council awarded a consultant contract to Halff Associates to develop the "City-Wide Drainage Master Plan Road Map" that was completed and adopted by the City Council in August 2010. The City’s primary goal and objective of the City-Wide Drainage Master Plan Road Map is to cost-effectively manage flood or storm waters within budget constraints so that conditions do not worsen as new and infill areas are developed. The Road Map provided a priority ranking of Grand Prairie’s watersheds. The third ranked watershed listed in this document is the Cottonwood Creek watershed.
The City-wide Drainage Master Plan for Cottonwood Creek provides comprehensive, updated technical data for the management of the Cottonwood Creek watershed. The information presented in the report provides planning alternatives and design concepts, and will supply the City of Grand Prairie with the necessary updated drainage information to coordinate future development and help minimize existing and potential erosion damages within the Cottonwood Creek watershed. The study is in compliance with the requirements set forth in the “City-wide Drainage Master Plan Roadmap.”
On December 14, 2010 the City Council awarded a consultant contract for the Cottonwood and Fish Creek FEMA CTP and Road Map Drainage Master Plan Study (Y#0881) in the amount of $344,512 to Espey Consultants, Inc. On April 5, 2011, the City Council approved Change Order #1 in the amount of $41,637, bringing the revised total to $386,149. The intent of these studies was to evaluate Cottonwood and Fish Creeks and to obtain a better understanding of our overall drainage, flooding and erosion situations in these watersheds. This plan will be used as a tool to prioritize and give a technical basis of how best to spend resources on solving flooding, erosion and other drainage issues.
The following work was performed as part of this study:
1. CTP FEMA DFIRM Mapping
a. Project Management and Outreach
b. Perform Field Surveys
c. Develop Hydrologic Data
d. Develop Hydraulic Data
e. Perform Floodplain Mapping
2. City-Wide Drainage Master Plan Road Map
a. Data Collection
b. Environmental Constraints
c. Review and Identification of Flood Drainage Area Problems
d. Necessary Field Survey Collection
e. Hydrologic Model Development
f. Hydraulic Model Development
g. Evaluation of Flood Protection Criteria, Measures, and Alternatives
h. Hydrologic and Hydraulic Analysis of Alternatives
i. Storm Drainage Infrastructure Analysis
j. Channel Stability Assessment/Erosion Hazard Analysis
k. Dams/Levees/Detention/Drainage Reviews
l. GIS Updates
m. Maintenance
n. Benefit/Cost Analysis
o. Implementation and Phasing
p. Short Term Priorities and Long Term Plan
q. Final Deliverables
r. Project Management/Coordination
Staff is recommending the adoption of the City-Wide Master Drainage Plan for Cottonwood Creek.
Financial Consideration
No funds necessary.
Body
A RESOLUTION APPROVING THE CITY OF GRAND PRAIRIE’S CITY-WIDE DRAINAGE MASTER PLAN FOR COTTONWOOD CREEK
Whereas, The “City-Wide Drainage Master Plan for Cottonwood Creek” (the Plan) is about providing comprehensive, updated technical data for the management of the Cottonwood Creek watershed; and
Whereas, the Plan addresses existing flooding, erosion, and sedimentation problems within the watershed and provides planning alternatives and design concepts to help alleviate potential flood damages; and
Whereas, the Plan provides the City of Grand Prairie with the necessary updated drainage information to coordinate future development according to the City's drainage requirements to help minimize existing and potential flood damages within the Cottonwood Creek watershed; and
Whereas, any revisions to the floodplain and the floodways identified in these studies shall also include ultimate development conditions and shall be for the whole creek as determined in these studies and not for portions of it to ensure that there are no downstream adverse effects; required submittals to FEMA shall be for the whole creek (as determined in these studies) and not for portions of it; and
Whereas, the recommendations of this report shall be incorporated for all future development as well as CIP budget considerations;
NOW THEREFORE, BE IT RESOLVED, by the City Council of the City of GRAND PRAIRIE, Texas that:
Section 1. That the City of Grand Prairie, Texas, having developed the “City-Wide Drainage Master Plan for Cottonwood Creek” to cost-effectively manage flood or storm waters within budgeting constraints, approves and adopts the “City-Wide Drainage Master Plan for Cottonwood Creek” thereby setting the standard for future drainage master plans, addressing existing flooding problems and providing planning recommendation, alternatives and design concepts for future development, to include CIP as well as possible developer participation projects.
PASSED AND APPROVED BY THE CITY COUNCIL OF THE CITY OF GRAND PRAIRIE, TEXAS, ON THIS THE 21ST DAY OF AUGUST, 2012.