The Town Council has approved an intergovernmental agreement with the Maricopa County Flood Control District for improvements along Ashbrook Wash.

The primary pieces of this project include the replacement of corrugated steel culvert pipes with concrete box culverts where the wash crosses Saguaro Boulevard and Bayfield Drive.

The three existing 60-inch culverts are undersized for flood flow and the box culverts will offer substantially more space for the water to flow.

Town officials said the work would be coordinated with the planned reconstruction of Saguaro Blvd. so that new pavement won’t have be ripped up for the culvert.

The council approved the agreement Dec. 5. This will allow design work to begin, which is to be done in house by the Flood Control District, according to Town Engineer Randy Harrel.

The total cost of the project is approximately $1.5 million, to be split with the district. The initial design phase, which was the part approved by the council, will cost the town and the district $75,000 each.

The remainder of the work is budgeted by both the town and the district for 2013/14 at $758,000 each.

In 2000 the town and district teamed up to make improvements to the retention dam at Golden Eagle Park. A previous inspection had shown the dam was at risk of failure under the right conditions.

The work in 2000 raised the dam by four feet and expanded the emergency spillway. It also increased the size of the outlet for water passing through the dam down the wash.

As a result of those improvements it was determined that during one-half a 500-year storm event there was potential for flooding downstream from the dam.

A subsequent study determined that 13 residential units along or near the wash were at risk for flooding in such a storm.

These new improvements will improve the flow through the wash to reduce the flooding potential.

Other work involved in the project would include some channel grading in the wash.

Vice Mayor Cassie Hansen asked whether the work would have any impact on the large cottonwood trees along and in the wash.

“It is our intention to have minimal impact on those trees,” Harrel said.

Councilwoman Ginny Dickey asked whether such a project might have been funded by the creation of a storm water district that collected fees from residents.

Town Attorney Andrew McGuire said this is exactly the type of project anticipated by a storm water district.

Mayor Linda Kavanagh said fees from such a district are really a tax, which she could not support.

This project is being funded using capital improvement funds. That money is dedicated from a portion of construction sales taxes and surplus funds at year-end – both of which have been in short supply in recent years.

Harrel said the Saguaro Boulevard culvert construction could be coordinated with the reconstruction and paving of Saguaro.