Title
Approving a Work Authorization Number 2020-3 as a supplement to the professional services agreement for the Water Treatment Plant Engineering Services with DCS Engineering, LLC. in the amount of $55,000 for professional services associated with the Raw Water Strainer Installation Project.
Summary
City Staff approved and executed a five year professional services agreement with the option to extend with DCS Engineering, LLC. on January 20, 2015 for consulting engineering services for the Water Treatment Plant. The agreement included a process for Work Authorization requests from staff to be approved by the City Council when exceeding $50,000.
The City discovered Zebra mussels have infested the 36" Raw Waterline to the plant. The full extent of this infestation is not known or readily obtainable due to the absence of inspection/pigging ports. Zebra mussel shells were found inside of the membrane basins in the Surface Water Treatment Plant last year and the sharp shells have been damaging the membranes since that time. This Work Authorization will provide professional engineering services to evaluate available alternatives to prevent zebra mussel shell fragments from further damaging the membranes, evaluate implementation schedules of each option to complete prior to approximately April 1st (i.e. flows start increasing and result in shell fragments dislodging from pipe interior), evaluate expedited construction of each option based on material availability and total construction cost, provide recommendations, generate construction plans, obtain TCEQ approval of plans, and oversee construction modifications. Preventing future additional damage to the membranes is of critical importance to the Surface Water Treatment Plant's ability to maintain its cryptosporidium removal rating and/or prevent train replacement at $500,000 per train. The system is currently operating with low winter flows at about 5 million gallons per day (MGD) which should minimize the ...
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