Dave Derrick, a research hydraulic engineer with the U.S. Army Corps of Engineers out of the Vicksburg, Miss. office in the Vicksburg District, inspects the area under a bridge near the third hole on the Fullerton Golf Course in Fullerton, Calif. Derrick completed his inspection of the stream running through the course Nov. 19 at the request of the City of Fullerton. The course is the main source of income for the Brea Dam Recreation Area and is managed by Fullerton.

Derrick works out of the U.S. Army Corps of Engineer Research and Development Center’s Coastal and Hydraulics Laboratory, Vicksburg, Miss.  At the request of Fullerton city officials, Derrick came out to see how he could assist the city. Alice Loya, Fullerton’s administrative manager for Parks and Recreation, said floods over the years have damaged the city’s golf course.
 
“How many people really have that kind of expertise in creeks and erosion?” asked Loya. “At first, we had thought of bringing in a regular contractor, but we know they don’t always have the specific expertise. I figured since it’s Corps property, the Army Corps would have someone with the experience to help.”

The course is the city’s main source of income for the Brea Dam Recreation Area. The course opened in 1963. Since that time, the stream running through it has flooded portions of the course many times, causing administrators to close several holes and re-design the course to accommodate the seasonal damage. The basic root of the damage, however, remained, and the city needed to figure out how to best manage it.
 
“The creek erodes the fairways and the golf cart paths,” said Loya. “It just makes them narrower. We needed assistance so we decided to call in the Army Corps of Engineers.”

In the areas around holes one, three and 10, the stream would regularly rise up into the course. This would impede golfers’ ability to enjoy a round.
 
Derrick came in and spent a day engaged in fluvial geomorphology, a fancy way of saying he studied how the motion of water changed the shape of the earth around it. His study consisted of assessing the stream to determine what measures might be appropriate for the area.
 
At one bridge, he found a chunk of concrete which was more than 20 feet wide and eight feet long had been dislodged and was choking off a portion of the creek. In other portions of the creek, riprap, a mixture of rocks and dirt in an earthen berm used to help with stream flow, was a concern to course officials. An underground tunnel emptying to a portion of the stream which led off the course was another item of interest and concern.

Derrick surveyed the entire length of the stream and proposed several items to Loya and to golf course officials.

“You want to take away as few degrees of freedom that the stream has as possible,” he said after surveying the area where riprap had been laid. “Vegetation is much cheaper than rock. Here, you’re taking away all three degrees of freedom. The bed is hard [because of the concrete laid into the bottom] and both banks are hard. If over time more water from the surrounding watershed is delivered to the stream, the stream can’t get any larger due to the riprap so it could flood more often.”

Since the riprap in this area was laid improperly – the side of the stream where the water would more likely hit was laid with a lesser degree of protection – Derrick suggested vegetation planted above the existing stone would better serve as a protective barrier.

Dave Derrick (in maroon shirt), a research hydraulic engineer with the U.S. Army Corps of Engineers out of the Vicksburg, Miss. office in the Vicksburg District, observes as an employee from the city of Fullerton, Calif., moves a chunk of concrete out of the stream running through the Fullerton Golf Course Nov. 20. At the request of city officials, Derrick inspected the length of the stream running through the golf course the previous day. The course sits on land owned by the Corps and managed by the city.

At the bridge, Derrick suggested the city or the course use local resources to remove the concrete chunk. He surmised the concrete had become dislodged from the stream bed during a flood and moved to clog the bridge which had been built just downstream. He was, however, impressed by the amount of vegetation several meters downstream from the bridge.

“This is great,” he said. “You’ve got diversity and complexity in the plants you have here. This is a great vegetated floodplain which allows the stream to transport water and sediment but also dissipates energy during a flood event.  Even if you do get some damage [from future storm surges], it’s self-repairing here.”

At the concrete path built as the bed of the stream near the 10th-hole tee, Derrick was blunt in his assessment of past repair efforts.

“It’s failed once, and it will fail again,” he said.
 
The main problem with the path as a route for water was the lack of a foundation and filter under the concrete channel. The concrete was designed to look like a sidewalk.  In a past rainstorm – not a major flood – the area under both sides of the concrete had already begun to erode. Someone had put in riprap on the sides of the runoff zone, but Derrick said a flood coming through would most likely create a channel on either side of the riprap area which was supposed to serve as the runoff area. This would probably increase the amount of damage instead of mitigating it.
 
In order to help the situation, Derrick suggested filling in the area under and around the sidewalk and stone with a dense gravel mix. Vegetated stone keyways and living dikes (dense rows of vegetation planted perpendicular to the direction of flow) should be built to protect the adjoining grassed areas.  Derrick, Loya and course officials spent the rest of the afternoon discussing the best way to implement some of his suggestions. The next day, Derrick returned to the golf course to get to work. He met with the course’s maintenance manager who had brought in an employee and backhoe to remove the concrete in the stream. With a backhoe and a few hours of work, the concrete obstruction was soon a thing of the past.
 
“If you can come out and fix it, then there’s no sense is just sitting and planning to try and figure out what to do,” he said about the concrete removal and other work performed immediately after the sit-down session. “We talked to [Los Angeles District] Regulatory and found we didn’t need a permit since we weren’t going to be changing any design. The concrete was already there. We just needed to remove it since it was blocking flow conveyance under the bridge. We just got a backhoe and an operator and went to work.”  During the course of removing concrete, the operator broke the bucket on the backhoe; however, Loya said work will resume soon with a city crew and jackhammers. Later that day, after consulting regulatory personnel, willow plantings cut on-site were installed at three other trouble spots along the stream to stabilize eroding banks.

The Corps owns the land the golf course is built on; however Orange County leases it and the city of Fullerton manages the area. Fullerton requested and covered the costs of Derrick’s visit. The assistance falls under the Corps’ Support For Others (SFO) work and is performed at sites around the country. Derrick has performed SFO work at other sites in need of his particular fluvial expertise. Loya said the golf course and the city will benefit greatly from Derrick’s suggestions.

“Having him here was very helpful,” Loya said. “He implemented some of the fixes the very next day with the golf course staff. We brought out maintenance department from the city and the golf course and Dave gave us all a lesson in how to treat some of this erosion.”

Derrick’s basic mantra was the use of natural means to help mitigate the damage the flooding stream would do to the golf course.
 
“You guys know way more about this stream than I do,” he told Loya and the golf course officials. “My job is to give you ideas of what would work better. The more you fill in this stream, the more problems you are going to have. You have a good stable bank and a really good assemblage of vegetation in many reaches and that needs to be left alone and protected.”

Loya said the city will continue to follow up on the advice given them by Derrick. In the near future, she expects the concrete to be removed, the willow plantings to be installed in the areas Derrick suggested and the area were the stream is undercutting the concrete to be properly filled.