My husband and I spent Memorial Day riding the Arroyo Mocho Trail to Concannon Blvd. with a return on the Isabel Avenue trail. It was a glorious day with lots of people about, in a holiday mood, obviously enjoying themselves. We were greatly surprised to see the usually dry arroyo full of water, looking almost like a river. However, it was a great pleasure to ride along the trail with water bubbling close by. In fact, it was almost like riding along the Truckee River.
Some of the Livermore natives informed us that the water comes from faraway sources to recharge the groundwater. I found an explanation at this link. Where the trail passes under Stanley Blvd. there was about three inches of water covering the path. I wanted to go cross at the signal on the road, but my husband proved that the water was not too deep by walking his bike through it. Since I had on shoes with open tops, I rode my bike–it was sort of a splashy thrill.
We had wonderful water views such as the one above all the way to Concannon Blvd., where Livermore assumed its usual dry but attractive aspect with lovely homes among the vineyards. And as is a custom with us, we finished our adventure with a lunch at Garré Winery.