Daniel S. Gilligan

Daniel S. Gilligan

Mr. Gilligan, one of three Managing Principals of Lennon, Smith, Souleret Engineering, Inc. (LSSE), joined the firm in August of 1994. He has over 40 years of practical experience in civil-municipal engineering firms and 4 years experience in physical oceanographic studies with the U.S. Coast Guard. His experience includes the planning, execution and management of regional municipal and environmental studies and municipal wastewater facilities plans for small, rural facilities, regional plans and large metropolitan sewage authorities.

His diverse experience includes wastewater facilities planning under the Federal Clean Water Act; Section 201 Feasibility Studies and Pennsylvania Act 537 guidelines; Federal Clean Water Act, Section 208 Area-wide Waste Management Studies; and Sewer System Evaluation Studies (SSES) including physical inspection, mapping, CCTV, dye testing, flow monitoring and physical surveys/data acquisition programs for fisheries studies, baseline open sea petroleum pollution surveys, meteorological studies, coastal domestic waste (offshore sewage sludge disposal) surveys, offshore toxic waste disposal site monitoring and bathymetric surveys.

Recent project experience included participation in the region’s largest wastewater assessment/facilities planning program for Allegheny County, PA, which involves the assessment of combined sewer overflow and separate sanitary sewer overflow problems throughout 83 municipal systems served by the Allegheny County Sanitary Authority (ALCOSAN). Mr. Gilligan was involved in the 3 Rivers Wet Weather Program Management contract in development and implementation of municipal coordination and infrastructure asset assessment programs, and in ALCOSAN’s Upper Monongahela Basin wastewater facilities planning study.

Since joining the firm in 1994, Mr. Gilligan has been responsible for development and implementation of the firm’s business development and strategic planning, business administration, management and marketing.


  • Engineering Design & Drafting Technology coursework, The Pennsylvania State University, 1968
  • Marine Science, U.S. Coast Guard Marine Science Technical School, Governor's Island, NY, 1969- 1970
  • General Business/ Environmental Studies, University of Pittsburgh, 1975-1979

Years Experience

Total - 42
LSSE - 22