How California's Flood Controls Work

Male1: If you have a functioning force that’s were the meadows get recharge and that’s were you start and attenuating a flood you need to look above and below a dam.

Male 2: And you need to look a the dam themselves and a possibly an presented level of coordination between two entrench federal bureaucracy the core of engineers has teamed up with the Bureau of Reclamation on the major renovation of Folsom Dam

Doris Matsui: I remember the date specifically June 2005 when we had a huge cost over runs. I thought what am going to do here? What are we going to do here?

Male2: What they did is abandon plans to modify the main dam in favor of entirely new spillway which own set of flood gates set apart from the main dam and situated well below it.

Doris: In essence, we were able to get them to work together and this is a way government should work and we came out with the better project with that additional spill way.

Female1: We can release the water as it starts to elevate in the reservoirs and we don’t have to let damaging releases it out and emergency type situations. It would be constructed down here; we got to shoot about 3000 feet and then runs right into the American river.

Male2: Long before work began at the Folsom site, the federal hydrology lab in Denver was already putting the new structure of the test.

Robert: This model we use the 1:48 scale which means that every 4 feet in the prototype is 1 inch in the model.

Male2: Robert Einhellig is one of the engineers who designed this working model of the dam and new spillway. Pumps drive water through the system is stimulate real flood conditions.

Robert: First of all we have to control the flow rate or the discharge of the water. How many cubic feet per second are passing over the main spillway or through the auxiliary spillway channel?

Male2: With the new editions, engineers hope to effectively double the flows that Folsom dam can handle without causing catastrophic flooding in the Sacramento area

Robert And so we’re evaluating how this new spillway is going to interact with the existing spillway and how to properly design this to handle the types of flows we anticipate.

Male2: Those flows that scientist and engineers are designing for are bigger than ever before, partly because of the newest problem in the next climate change. Scientist largely agree that California’s climate is warming. As it warms the Sierra snow pack retreats farther up the mountains and melts off sooner. It’s estimated that within the century, the snow pack could dwindle by 60% or more.

Male3: The dwindle last 50 years has been that we are getting more rain and less snow and bigger variation and climate, yearly variation in climate. That variation coupled with that shift to more rain and less snow means higher peak flows in the winter and possibly more high flows in the winter.

Male2: If current trends continue, what we now consider be one hundred year flood event could occur once every 10 years.

Male3: They way we calculate risk comes basically from as a statically analysis of historical flows. We use that statically analysis and we use that then to predict the future but that’s wrong, we all agree that’s wrong, that the future is going to be different than the past.

Male2: The future of flood control on the Sacramento valley will be different in many respects. Costs and environmental pressures make anymore large scale dams unlikely. We’ll still rely on the levees for a last line of defense but the costs of maintaining those levees will shift more toward the people who live and work behind them. And planers will likely look up stream for coordinative solutions that take into account the entire water shed in this region at risk.

Female2: I really do think we need to push for the water shed first. I think if we don’t—it does not matter how many billions of dollars we throw at the problem, we would be…

Male2: Sticking our fingers in the dike.

Female2: Stick in our fingers in the dike, that’s right.

Doris: We are together on this. Whatever happens to the water shed affects every single one of us and I believe that we have the water shed approach instead of project by project.

Female1: I think if we would become a stand solid and we show that all levels of government are behind us and this truly the right way to go, I think things can happen. But it’s not normal that everybody works together, you know maybe it’s safety in numbers or your mis relapse company whenever you want to call it, you know we are all the same boat and I think we are all traveling in the same direction.