The arboretum waterway served its purpose as a storm-water detention basin during the Jan. 4 storm, but the rising water overflowed an earthen dam that had been put in place for a pipeline project just west of the California Avenue bridge.

Campus authorities said the bridge supports did not sustain any damage as water backed up behind the temporary dam. The dam stayed in placed, but, because of the inclement weather, Tidelands Construction Co. is now about a week behind in installing steam and chilled-water lines under the waterway.

In preparation for that work, the university drained the waterway more than normal, and Tidelands installed a 67-foot-long culvert and built the dam to channel water through the culvert. But the Jan. 4 rainstorm brought more runoff than the 36-inch-diameter culvert could handle.

Now, Tidelands is optimistic that the soil under the waterway has not become overly saturated, said Scott Arntzen, a senior project manager for the campus’s Architects & Engineers unit.

If water seeped down more than a foot, the contractor must wait for the soil to dry out before starting to excavate for the pipelines, Arntzen said.

Assuming the site is ready to go, excavation for the pipes could begin Jan. 11, Arntzen said, and construction work in the waterway could be completed by around the first week of February.

The contractor’s job is to extend steam and chilled-water lines to the Robert Mondavi Institute for Wine and Food Science, now under construction on the south side of Old Davis Road.

The project has been under way since summer, mainly along Old Davis and La Rue roads. This has meant traffic controls and delays for motorists.

Now, with the construction zone extending into the waterway, the bigger impact will be on people who walk, run or bicycle through the arboretum, Arntzen said.

“You’ll have to get up out of the creek area when you get to the California Avenue bridge,†he said. Those detours remain in place (see detour information below).

An earlier plan called for attaching the new pipelines to the California Avenue bridge, which already supports a number of other utility lines. But engineers later decided to put the new pipes under the waterway.

The detours

Detours are posted to keep people out of a construction area along the arboretum waterway in the vicinity of the California Avenue bridge. This means that people cannot follow the arboretum paths under the bridge. Signs are posted to get people around the work zone.

On the south side of the waterway -- Near each closure point, an alternate path climbs up to California Avenue. Cross the street, and then follow the path back down to the waterway.

On the north side of the waterway, if you are going west -- Near the closure point, an alternate path takes you up to the intersection of California Avenue and La Rue Road. From here, cross over the California Avenue bridge and walk back down to the waterway; this puts you on the south side of the waterway.

Note, however, that the California-La Rue intersection is near the Physical Sciences Expansion construction zone. You can avoid this area altogether by crossing from the north side of the waterway to the south side via the footbridge about 300 feet east of the California Avenue bridge.

On the north side of the waterway, if you are going east -- Cross the footbridge near the Cole Arena, and continue your journey on the south side of the waterway. When you get to the California Avenue bridge, follow the alternate path up to California Avenue, cross the street and then walk back down to the waterway.

An access road is an alternative route on the north side of the waterway for people walking or biking between King Hall and La Rue Road. However, this road is also within the Physical Sciences Expansion construction zone.

Arntzen of the Architects & Engineers office said the access road will not be closed, but, should you wish to avoid the construction zone, a detour is posted—even though it could add four or five minutes to your walking or biking.

From King Hall, the detour runs along the west side of King, and then follows the path between the Physics-Geology Building and Bainer Hall. This path connects to Bainer Hall Drive, and Bainer Hall Drive takes you to La Rue Road -- completely avoiding the construction zone and the California Avenue-La Rue Road intersection. A map shows the detour.

The map also shows the location of the path closures along the waterway in the vicinity of the California Avenue bridge, and the alternate paths on the south side of the waterway.