The torrential rains that ran through between Christmas and the New Year had, to say the least, a substantial effect on the environment of this part of the coast.
Parts of downtown San Anselmo were submerged under up to four feet of water, while mudslides were reported in Inverness, Fairfax, and San Rafael. The Russian River swelled, drowning out many of the villages that nest at its banks. It is estimated that, state-wide, the total cost for repairing the damage is roughly 100 million.

But our watershed was also badly mauled. Creek beds carved to hold creeks were strained, and in some cases failed completely, in containing the powerful rapids. Currents carved away many creek walls completely, even as the feeble trees that clung to the soil came toppling down. The sediments that formerly contained the creeks eroded away and were rushed downstream.

All of this sediment ended up in either the Pacific Ocean or in the San Francisco Bay Estuary. According to the Environmental Protection Agency's National Coastal Condition Report II (2005), many West Coast estuaries, including ours, already suffer from low water clarity. With the deposition of more sediment in our water, water clarity is even lower.

What are the effects of low water clarity?

Firstly, less sunlight reaches threatened plants such as eelgrass that grow on the sea floor.

Second, albedo, the reflectivity of water, is increased, causing higher amounts of radiation in the air rather than safely absorbed by clear, clean seawater.

Also, once the sun comes out, visible light absorbed by the suspended sediment will heat the water in turbidity. Turbid waters, accompanied by the high levels of phosphorus such as those that plague the bay, are ideal for algal blooms. At the end of the blooms' short life span, the remaining pond scum will proceed to be eaten by aerobic bacteria. To function, the bacteria draw vast amounts of dissolved oxygen from the water, leaving less available for native fish and plants. With less fish in our bay, not only will the local ecosystem be devastated, but our local fisheries and businesses that rely on local marine wildlife will be economically unproductive.

But more important than the effects are the causes. Our levees might not have been in the best condition to prevent flooding, but that doesn't explain the condition of our natural defenses. What state have our local waterways been in? Any running body of water requires plants, preferably native dicotyledonous plants with strong, deep roots, to hold the soil in and prevent erosion. But rather than natural methods of containing a creek, we're using methods that are destructive to our local environment.

Our creeks, once meandering with the topography, have instead been channeled with cement to create uniform, straight waterways.

Suburban creeks are not city streets; they need to be curving as to accommodate flora and fauna that depend on it for survival. Straight creeks do not deposit sediment as well as curvy creeks. Creeks straightened with cement channels are worse. As soon as the water hits the dirt at the end of the channel, that wall is violently torn away by the rapid current. A common method of preventing erosion is riprap, or the placement of large stones to hold down a slope. Unfortunately, this practice makes the soil beneath unstable and does little to prevent erosion.

The most effective way of restraining a creek is to leave as it should be according to nature. If the creek has already been straightened, plant native flora in the riparian corridor to ground the soil as best as possible. Alien grounding plants, such as periwinkle (Vinca major), English ivy (Hedera helix), and the non-native Himalayan blackberry (Rubus discolor) are poor choices, as they quickly take over the creek, take away biodiversity, and strangle native plants.

Marin County Stormwater Pollution Prevention Program (MCSTOPPP) has several tips for restoring any local riparian corridor. For more information, visit their website at http://www.mcstoppp.org or call 499-6528.

We've recently witnessed already some dramatic consequences for our actions or lack thereof. It has happened before, and it can happen again.