Founded in 1990 by Michael McDonald and Daniel Morrissey following distinguished careers with the U.S. Geological Survey, MMA was built on a foundation of groundwater science and quantitative analysis.
Mike McDonald developed MODFLOW, now the world’s most widely used groundwater modeling code. That commitment to technical rigor continues to guide MMA today.
McDonald Morrissey Associates has been solving complex groundwater problems since 1990. Nationally recognized for the analysis of groundwater flow systems, MMA combines decades of specialized experience with sophisticated quantitative modeling and practical, independent technical guidance.
Since 1990
More than three decades of specialized groundwater consulting.
100+ Years
Combined experience among MMA principals.
MODFLOW Legacy
Mike McDonald, co-founder of MMA, developed MODFLOW, the world’s most widely used groundwater modeling code.
National Expertise
Complex groundwater projects for industrial, legal and government clients throughout the United States and internationally.
Our Expertise
Quantitative Science. Practical Answers.
MMA combines hydrogeologic expertise with quantitative modeling to help clients understand groundwater systems and make technically sound decisions.