Located on the Columbia River, the Butterfield Intake plays a crucial role as a reliable drinking water source for the City of Pasco. The screen quality was deteriorating, and it could not meet the Butterfield WTP’s 28 to 30 MGD capacity. Our original scope covered refurbishing the existing screen and installing a second traveling screen. However, further review of the data combined with new regulatory requirements required a solution that was far more complex than the City originally anticipated. We prepared a technical memorandum summarizing the new regulatory guidelines and the resulting Butterfield intake facility capacity, and the City requested that RH2 amend the original scope to meet the new regulations as well as the future WTP capacity.
Our revised concept called for installation of two 17 MGD barrel screens and routing two 36-inch diameter HDPE pipes through a trough outside of the existing intake structure. A phased approach for electrical and SCADA improvements kept the facility operational during construction. Permitting efforts were complicated by the number of agencies involved, including the requirement that that all in-water work needed to occur within a narrow window from December 15 through March 15. Ballard Marine Construction completed the work, and the new screens and upgraded facility were online in time for irrigation season of 2016, meeting the current 30 MGD demand.
Several months after completing the improvements, the Army Corps of Engineers released a report requiring all intake facilities in the District to comply with the new environmental regulations by 2020 in order to renew their easements. Because the City’s new intake facility is now in compliance with this requirement, they will not have to secure last-minute funding for additional improvements to meet the 2020 deadline. The City is very pleased with the results of our project, and we have continued working with their staff to assist in monitoring operations.