Mood: The ins and outs of storm drainage, wash maintenance

(Submitted photo)

On Tuesday, Oct. 2 the Town of Paradise Valley experienced heavy rainfall in the wake of Hurricane Rosa.

The Maricopa County weather station near the intersection of Tatum and Shea boulevards recorded a 24-hour rainfall total of 3.70 inches.

The weather station at the Paradise Valley Country Club recorded 3.39 inches and the weather station near the intersection of Doubletree Ranch and Invergordon roads recorded 3.74 inches.

(Submitted photo)

During and after this storm event the Public Works Department fielded numerous calls from residents regarding flooding and debris in the roadways. During the 2018 monsoon season the Public Works Department has removed approximately 300 tons of dirt and debris from Paradise Valley roadways to date.

After this storm event the town’s engineering department is still in the process of following up on numerous drainage related issues reported by residents. In many instances staff is finding that improper maintenance of washes and residential storm drainage facilities are contributing to property damage as well as damage to the town’s infrastructure.

Staff has encountered washes, drainage channels and retention basins that have been filled with silt and debris, which reduces their capacity to carry or retain water. Numerous culverts, trash racks and storm drain openings were found covered with branches, leaves and other debris causing water to back up onto properties or spill out into the roadways.

Wall openings were also found to be blocked with boards, rocks or chicken wire. These blockages prevent proper drainage or allow for debris to be collected and block the openings. Many properties were also found to have altered their landscaping and drainage facilities, which resulted in property damage.

During site visits, the engineering staff will evaluate a property, recommend potential solutions to improve drainage and go over proper maintenance of drainage facilities. Property owners are encouraged to inspect their storm drainage facilities before each monsoon season and after any significant rainfall to make sure they are in proper working order.

The town annually mails out flyers to all residents regarding wash maintenance and residential storm drainage facilities maintenance. This information can also be found on the Town’s website at:


The Town Council has taken steps to ensure that proper drainage design is incorporated into new construction with the recent adoption of the 2018 Storm Drainage Design Manual. This is the first major update to the manual since 1987.

This manual provides standards for storm water retention on “flat land’ and “hillside” lots, guidelines for any alterations to washes, and storm drainage facilities agreements. The Town Council also adopted new Hillside regulations, which requires projects to submit a Hillside safety improvement plan that looks at existing geology, slope stability, boulders, drainage and blasting if necessary.

During this rain event two incidents were reported on hillside properties. One property had a large boulder fall onto a driveway and another property experienced a rock slope failure.

Residents are strongly encouraged to keep up with inspections and maintenance of their storm drainage facilities and to report any blocked storm drains or culverts they may see in the town’s roadways.

The town’s engineering department may also be contacted at 480-348-3573 to discuss any drainage questions, concerns or have a staff member walk a property with a homeowner.

Editor’s note: Mr. Mood is the town engineer at the Town of Paradise Valley

(Submitted photo)

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