1902: Allen Hazen co-develops the Hazen-Williams equation, which is used in the design of water pipe systems such as fire sprinkler systems, water supply networks, and irrigation systems.

1904: Allen Hazen recommends the filtration of the Croton water supply for New York City. In 2015, Hazen staff led the commissioning of a new filtration plant on that water supply.

1908: President Theodore Roosevelt sends Allen Hazen as part of a panel of expert engineers to inspect the construction progress on the Panama Canal with President-Elect William H. Taft.

1937: Richard Hazen graduates Harvard University with an MS in Sanitary Engineering and begins his career as a consulting engineer.

1950: Richard Hazen begins private practice in New York City, convincing Alfred Sawyer to join him a year later to form Hazen and Sawyer.

1952: One of the first projects undertaken by Hazen and Sawyer was a major infrastructure improvement program in Monrovia, Liberia.

1956: The City of Greensboro, North Carolina, is one of Hazen and Sawyer's longest standing clients. Projects for Greensboro such as the Lake Brandt Dam influenced our expansion into the Mid-Atlantic states.

1957: Our work on the Springwells WTP project in Detroit led us to open our first branch office there in the mid-1950s.

1961: Our first project for the New York City Department of Environmental Protection was at Tallman Island WWTP. Since then we have worked on numerous major programs and projects for the DEP.

1962: Our work on the New York World’s Fair included design of 8 miles of new sewer and 9 miles of stormwater system over a 600-acre site, as well as water quality analysis and treatment for lakes in Flushing Meadow Park used for aquatic sports and exhibitions.

1966: This Springfield, MA, project involved an 8-mile-long, 48-inch transmission main and 60-mgd pumping station to supplement an existing reservoir.

1971: Hazen and Sawyer designed the original 18 mgd Plum Island Water Pollution Control Plant serving Charleston, SC. The facility has continued to retain Hazen and Sawyer for consultation and upgrade/expansions to its current permitted capacity of 36 mgd.

1976: The Chamberlain Street Tank is a 5 million gallon prestressed concrete water storage tank constructed to increase available finished water storage in the City of Raleigh, North Carolina's primary service zone. The project included a major upgrade of the recreational facilities at the popular neighborhood park on site.

1979: For the Miami-Dade County Water and Sewer Department in Florida, we completed work on a new 60-mgd plant to serve the northern portion of the County. Known today as the North District Wastewater Treatment Plant (pictured here in 1977), we have subsequently provided design and construction management services for expansion of the plant to 60, 80, and 100 mgd.

1980s: Located on a very restrictive site in the former Brooklyn Navy Yard, the prize-winning Red Hook secondary treatment plant incorporates energy conservation through 100% utilization of bio-gas.

1987: In association with NOAA and POTWs in southeast Florida, Hazen and Sawyer performed a series of unique ocean outfall monitoring studies called the Southeast Florida Outfall Experiment (SEFLOE). The SEFLOE studies were the impetus behind legislation favorable to the specific outfalls studied being written into the Florida Administrative Code. Hazen and Sawyer continues to work with the utilities and NOAA to implement the Florida Area Coastal Environmental initiative.

1993: Hazen and Sawyer was retained by the South Florida Water Management District to evaluate the regional economic impacts of a stormwater control and treatment system as it affects sugar, vegetable and sod production in the Everglades Agricultural Area. The study was the first of its kind to assess the regional economic impact of Everglades restoration south of Lake Okeechobee as it affects an industry.

1997: We performed a 12-month oceanographic and hydrodynamic field data collection program to inform an Effluent Disposal Feasibility Study for the City of Cartagena, Colombia, then going on to develop the City's master plan for wastewater treatment and effluent disposal. The work was funded by part of the $200 million in loans secured from the World Bank to upgrade water and wastewater works.

2000: For a project in Jordan funded by USAID, we provided the final design to restructure nearly half of Amman’s water distribution system, along with the construction management of water towers, reservoirs, pumping stations, and pipelines.

Present: The 290-mgd Croton Water Filtration Plant, constructed entirely under a driving range in the Bronx, can provide roughly 30 percent of New York City's current daily water needs, providing critical system flexibility and redundancy.

Present: The Miami-Dade High Level Disinfection Upgrade resulted in one of the largest HLD facilities, and the largest OSHG facility, in the U.S. The 285-mgd plant was successfully placed in service about 15 months ahead of schedule and approximately 10% under the $618 million budget.

Present: For Metro Nashville Water Services Department, we’ve designed an equalization facility adjacent to West Park and the West Park Pump Station. It is the first joint wastewater and park project in the U.S. to receive an ISI Envision rating award and the tenth project in North America to receive recognition.

Present: For Sanitation District No. 1 of Northern Kentucky, we're providing full system solutions to address CSOs and SSOs, comparing the costs and benefits of using integrated gray, green and watershed controls to achieve water quality improvements more quickly and effectively.

Present: The completed Gilboa Dam Rehabilitation restored all features to their original functionality, upgraded the dam to current industry criteria, and provided an enhanced dam safety monitoring and reporting system.

Present: We are helping many of our clients in southern California add additional groundwater capacity, using a variety of different water treatment, system design, and project delivery methods.