Erosion Control Work Started on Tecolote Canyo

After five years of studies and meetings with community groups, the city of San Diego has begun work on a $1.4-million erosion-prevention project in Tecolote Canyon that is designed to reduce silt runoff into Mission Bay by 40%.

In recent years, heavy rains, crumbling stream banks, and increased waste water runoff from houses above the six-mile canyon has caused silt to flow into Mission Bay at a faster pace, James F. Prescott, associate civil engineer for San Diego said.

“The silt gets into the bay and effects the bottom life, and if it gets bad enough it can also effect boats in the bay,” Prescott said.

To slow the amount of silt running into Mission Bay, some of the stream banks will be reinforced with riprap (rocks), and to preserve the canyon’s natural appearance more than 40 species of native plants and seeds (cotton willows, eucalyptus trees, and blackberry bushes) will be planted over the rocks.

In addition, rocks will be placed on the stream bed, along with three rectangular dams. The rocks in the stream will slow the speed of the water, so that the box-like dams can trap the silt.

Construction on the project began several weeks ago.

The Tecolote streams empty into Mission Bay at the Pacific Passage side of Fiesta Island.

The project is being funded through city’s Transient Occupancy Fund. The plants and seeds will cost $300,000 and the rocks, grading, and installing the dams another $1.1 million.

The project will lead to some financial savings for the city because there will be longer intervals before Mission Bay needs to be dredged.

“We want the most silt retained for our dollar. By keeping more dirt in the canyon it will help preserve the canyon. It will also save the city some of the money that is now being spent in legal fees to obtain permits to dredge the bay,” Prescott said.