In Memoriam: Al Colthorp

February 2012, Vol. 67 No. 2

Al Colthorp of Lake St. Louis, MO, died on Oct. 18, 2011 at the age of 77. Colthorp graduated from Michigan State University with a masters in Civil Engineering, and was a registered Professional Engineer.

In the early 1960s, Colthorp joined Penetryn and began his career in the sewer inspection, evaluation and rehabilitation business. While at Penetryn, he helped develop the technology to grout small diameter sewers. In the early 1970s, Colthorp was the general manager of the Restoration Division, which was involved with soil stabilization and grouting railroad tunnels. His work in these areas led to sealing leaking pipelines from the exterior. He then became involved with infiltration and inflow removal from sewers and started grouting small sewers from the inside using equipment from the UK.

Colthorp’s skills encompassed more than technical applications. He also played a role in shaping the Federal Water Pollution Control Act (PL 92-500), implemented in 1972.

In 1980, he joined Insituform of North America (INA), a licensee of Insituform International in the UK. He was instrumental in constructing the company headquarters building in Memphis, and signing-up and training new sub-licensees to install the Insituform CIPP product. He then became director of marketing for INA, and when he left in 1985, INA was a thriving company with rapid growth.

Colthorp next joined Insituform Mid-America (IMA) in Chesterfield, MO, where he served as technical director. In the mid-1990s, Insituform Technologies merged with IMA, with the new headquarters located in Chesterfield where he continued in a technical role in the Engineering Department until his retirement in 2001.

Colthorp belonged to and participated in several industry organizations. However, NASSCO was his favorite, and he continually looked forward to the meetings and interaction with friends. He was a founding member and past-president of NASSCO and served on the board for many years and took delight as the first inductee into NASSCO's Select Society of Sanitary Sewer Sleuths.

Colthorp is survived by his wife Marie; children Lynn (Bob Cappucino), Cynthia (John Nagel), Alan (Angela), Scott and Craig (Maria); step-children Constance Graziano, John (Erin) Graziano and Carol Graziano; and many grandchildren.

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