March 2017 – Law and Civil Engineering

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Determination of Liability for Flooding Damage is Not So Simple
by Eugene Bass

A County owned a drainage system in a subdivision upslope from a neighboring property that contained a drainage channel. The County system connected to the channel which conveyed the flow out to a river. Flooding had occurred in the subdivision that the County contended was caused by the downstream owners failure to maintain the channel. The downstream owner took the position that it had no responsibility to protect the channel.

Drainage law in California has evolved over the years. The early rules were that the upper property owner was entitled to discharge surface water from his land as the water naturally flowed but was liable for any damage caused to adjacent property by the discharge of water in an unnatural manner. Essentially, each property owner was required to leave the natural flow of surface water undisturbed. This rule, while somewhat applicable to rural areas, was inappropriate for urban land.

In time, more reasonable but imprecise rules developed to accommodate the realities of urban development and the increased runoff that resulted. A reasonableness test evolved. The test was whether, under all the circumstances, the upper landowner’s conduct was reasonable. The rule of reasonableness applied to both private and public landowners and it required reasonable conduct on the part of downstream owners as well.

Over time, 5 factors were identified involving public projects, to determine if the parties actions were reasonable. They were (1) The overall public purpose being served by the improvement project; (2) the degree to which the loss to the party damaged (the plaintiff) was offset by reciprocal benefits; (3) the availability to the public entity of feasible alternatives with lower risks; (4) the severity of the plaintiff’s damage in relation to risk-bearing capabilities; (5) the extent to which damage of the kind the plaintiff sustained is generally considered as a normal risk of land ownership; and (6) the degree to which similar damage is distributed at large over other beneficiaries of the project or is peculiar only to the plaintiff.”

In the case of the subdivision drainage system that discharged into the channel through the downhill neighboring property, the owner of the channel had failed to maintain and clear the channel over the 30 year period that it had owned the land. As a consequence, the channel became obstructed with large trees, bushes, debris, and sediment and upstream flooding resulted. The channel had been improved and maintained over the 20 year period prior to the purchase by the current owner and it’s existence was open and obvious to the buyer.

The County sued the property owner for damages arising from having to deal with flooding of the upstream property. The court determined that the drainage channel is a natural watercourse, that the County’s conduct with respect to its property had been reasonable, and that the downstream property owner’s failure to maintain the drainage channel had been “entirely unreasonable” in light of its actual or constructive knowledge when purchasing the property of the existence of the drainage channel and the need to keep it clear of debris to prevent flooding to the adjacent homeowners. The court awarded damages to the County and ordered the downstream owner to clear and maintain the obstructed drainage channel.

The assessment of liability in cases involving the flooding of upstream or downstream properties arising from actions on those properties can involve complex legal and factual issues that can vary on a case by case basis and should be approached with the advise and assistance of experienced legal counsel.


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