F-23: Storm Sewer Under-Design

 Statement of the Case: A long-established town was rapidly expanding in size because of the
recent development of a pulp-mill and a mine, both near the town. The downtown was changing
rapidly. New four-storey buildings were replacing the old single-storey false-front buildings. The
main street, originally a two-lane blacktop with rudimentary drainage ditches and short sections
of asphalt sidewalk, was being widened and improved. The town Council envisioned a four-lane
asphalt road with concrete curbs, gutters, and sidewalks, and storm sewers with a long outfall.
The town would receive 25 percent of the capital cost of the project as a grant from the province,
but the town’s finances were low, and funding for the balance was unavailable. However, the
town would be able to raise the remaining 75 percent of the cost when the mill and mine were in
production and tax revenues increased. The town therefore decided to proceed on a staged basis over four years, starting with the storm sewer construction in the first year. The town engaged

Engineer A to provide the design and the field services.

Engineer A was aware that cost was an issue, and using an accepted statistical approach, he

proceeded to design the storm sewer based on a 20-year storm, which he believed was the

minimum capacity that was reasonable under the circumstances. However, his preliminary cost

estimate was much higher than the town Council expected. After a brief discussion, the clerk of

Council met with Engineer A, asked if costs could be further reduced, and told him how much

money the Council believed that it could afford. Engineer A accepted this cost limitation without

comment. He calculated that the limit could be met only if the criteria were reduced to that for a

2-year storm, then he redesigned the storm sewer to this lower capacity. The Council approved

the re-designed project, issued contracts for construction, and built the storm sewer.

Question: Is it ethical for Engineer A to accept a cost limitation even when he knows that it will

reduce the design below accepted standards? What should Engineer A have done in this case?

Outcome: The next year, a rainstorm overwhelmed the storm sewer and flooded the downtown

basements, causing extensive property damage, especially to retail merchandise. The residents

sued the town Council for damages, but the cases were later settled out of court. The Council, in

turn, sued Engineer A. In addition, the Council made a formal complaint to the provincial

Association concerning Engineer A. The complaint was stayed (suspended), pending the

outcome of the civil case.

Authors’ Comments: When the town Council asked Engineer A to reduce the design capacity,

he had a duty to inform them of the accepted standards in this type of design and to warn the

town of the consequences—a far more serious risk of flooding—if his judgment were over-ruled.

Most provincial and territorial Codes of Ethics state this duty clearly.

For example, Engineer A should have explained that designers now use storm periods in the 10-

to 30-year range and the old 2-year period has been superseded. Although the 2-year design was

affordable to the town, it carried a much greater risk of damage settlements or lawsuits. If the

Council had still insisted on the 2-year design, Engineer A would have discharged his duty to

advise his client. The town Council would have had the full information, and the decision (and

the risk) would have been theirs. Whenever the judgment of the engineer or geoscientist is overruled,

the professional must caution the client (preferably in writing) of the likely consequences

and make note of the client’s reply.