An inquiring Lafayette resident recently dropped into the historical society with the closest we’ve 
ever gotten to an aquatic engineering question: when was the Weir at the end of 4th Street built and why?
Luckily for our curious visitor, the weir at 4th street not only has a story, it has a partner at Victoria Court. Weirs, which are a variety of dam, are built to alter or regulate the flow of rivers and creeks. In this case, the two weirs in Lafayette came into being after two very wet winters in 1938 and 1939. Log jams caused by tumbling black walnut trees widened the course of the creek, and land on both sides was reclaimed by water. Something had to be done!
The flooding got so bad that the bridge at Moraga Blvd and 4th Street had to be rebuilt by the city in order to prevent its demise. With rising water the county quickly realized a weir at 4th Street would be a good solution to moderating the creek in the long term.
Some local residents that lived in the Lafayette Manor Tract just down the creek near Victoria Avenue got wind of this and formed the Las Trampas Dam Club in 1940 to advocate for a second weir nearVictoria Court. The Dam Club was motivated with good reason: rising water had encroached on several owners properties, sometimes even coming up onto the back porch of hapless residents.
Meeting in Earl Wise’s garage, the club had 5 members; Geo. Williams, Mr. Van Es, Bud Blamy, George Gelhaus and of course, the owner of the‘clubhouse,’ Earl Wise. Each member donated $300 each to make the second weir, and the solicited nearby residents for donations and pledges for the betterment of the community.
With money under their belt, the group shopped for materials, hired government engineer surveyors to make plans, and petitioned the county. By winter 1941 the two weirs were under construction, with the county graciously furnishing the labor for the Victoria Court weir. Interestingly, most of the materials of the weir were local, with rock purchased from Clayton, and cement from Burt & Lloyd in Lafayette.
The impressive structures were built and completed by the next wet winter, where they proved their merit in protecting life and property in the area. Both weirs still stand, regulating the creek and preventing any residents from getting a backyard swimming pool they had not counted on!
The complete accounts of the activities of the Las Trampas Creek Dam Club dated December 20, 1940 as well as many photos of the building of the weir are available in the Historical Society’s archives.
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