We live in an apartment that is across the street from the Lower Guadalupe River and its levee. Since it is so close, we spend a lot of time on the levee walking, jogging, and biking. In the river channel there is abundant wildlife, so for us the levee is a magical place.
Recently we were invited to a community meeting held by the Santa Clara Valley Water District to solicit public input on a proposed plan to improve flood control along the lower end of the river by making changes to the levee.
The problem being addressed is that, when it was constructed, the river channel and the levee were designed to protect the area around it from a 100 year flood. At that time, salt water came up the channel as far as Montague Expressway before encountering fresh water coming down the river. In the lower channel, only salt water adapted plants could grow. These plants tend to be small and cause only minimal obstruction to water flowing in the channel.
In the present day, salt water comes only as far as the Tasman bridge, one bridge downstream from us. So now large freshwater plants and trees fill the channel, and as a result, the height of the levee is several feet too low to protect us from a 100 year flood.
The picture below shows what the lower river channel used to look like all along its length, but now only down near San Francisco Bay.
Now the channel near our apartment is filled with vegetation that blocks the channel and reduces its capacity to hold flood waters.
The solutions being considered include various ways to increase the height of the levee, build a wall on the levee, and remove vegetation.
Our little citizen group brainstormed with staff from Valley Water on some of these ideas as well as identifying stakeholders of the river and levee in our neighborhood.