Hazen and Sawyer to Provide Consultant Demand Professional Engineering Services to Gwinnett County
Contract Extends Eight-year Record of Work for the County
(RALEIGH, NC- February 27, 2009) – Gwinnett County’s Department of Water Resources awarded Hazen and Sawyer a multi-year, on call service contract, extending the firm’s eight-year record of work for the County. Since 2001, Hazen and Sawyer has performed more than forty assignments for the Department on water, wastewater, and other County facilities. Assignments have ranged in scope from simple analyses to multi-million dollar design programs.
Recently, Hazen and Sawyer completed work for the County to mitigate the risks of decreasing water levels in Lake Lanier, the County’s sole source of water supply. The project encompassed the development of two innovative forecasting tools. The first is a reliability calendar that assesses the likelihood of occurrence for critically low lake levels in the near future. The second charts “worst case” inflow, identifying starting conditions from which occurrence of critically low lake levels is possible. Gwinnett County now uses these two forecasting tools to trigger contract implementation phases on an emergency, land-based 100 million gallons per day (mgd) pump station. This phased implementation allows Gwinnett County to optimize its financial expenditures by committing costs (for leasing the pumping station) as they become risk-justified (triggered by low reservoir level and inflow predictions). Furthermore, decision-makers within the County are using the tools to educate various stakeholders about actual, real world risks to supply, enabling them to understand and support the County’s water resource management decisions.
Among other work, Hazen and Sawyer has also provided engineering services for improving the Lanier Filter Plant’s residual handling system that treats spent backwash water from both the 150-mgd Lanier Filter Plant and the 75-mgd Shoal Creek Filter Plant. The project included the design of two 2.5 million gallon cast-in-place concrete tanks, an equalization tank mixing system, a variable speed vertical turbine pump station, and a new electrical building. Hazen and Sawyer retrofitted the existing backwash equalization tank with four new vertical turbine pumps to recycle the clarified backwash water to the raw water reservoir, and designed a filtrate equalization system with pH adjustment prior to discharging the filtrate to the backwash equalization tanks.
For this latest contract, Gwinnett County rated Hazen and Sawyer highest out of eleven teams that submitted proposals based on the firm’s technical capabilities and close knowledge of its system. The Gwinnett County Department of Water Resources presently completes the majority of its engineering projects by employing Demand Service contracts.
Since our founding in 1951, Hazen and Sawyer has focused on two things: providing safe drinking water and controlling water pollution. Our range of services encompasses the planning, design, and construction management of water and wastewater-related projects – from clean water treatment, storage, and distribution to wastewater collection and treatment.