500 words on Erosion

With the first winter rain, come the fears about mudslides, high surf, and erosion. Property owners feel imperiled by the slipping slopes above their homes, but what about the wildlife who have their nests and burrows wiped clean from the earth by rushing waters, or the fish that have their homes turned into salvage pits? This week, as strong (by California standards) winter storms sweep into Southern California, erosion will nudge Tiger Woods from the headlines for at least a couple of days.

The first evacuation orders have been ordered in the “burn zone” of the Station Fire. The landscape is left desolate and unprotected in the wake of a brush fire. Without roots of chaparral clinging to hillsides to keep them in place, the slopes will flow down with the rushing water. These hillsides on the crawl will threaten the homes and structures that get in the way, leading to flooding, mud damage, and hazards created as heavy objects get pushed down the mountain.

Water has to flow somewhere, and while a few inches of mud in the living room might be devastating to homeowners, the thousands of gallons of now-toxic sludge flowing “downstream” is devastating to us all. Rain water picks up a lot: oil drippings from cars and trucks which have rested as black spots on the pavement; excess fertilizer, chemicals and poisons we dump into our gardens, lawns, and parks. Rough surf slams into the retaining walls we build to prop up and protect our multi-million dollar beach homes, stripping the beaches that give these glass palaces their value.

The mudslides in the hills get all the attention, but the flow of pollution which picks up steam in the flats can have much longer term damage. The harm of oil and chemicals is obvious to most with an elementary education, but did you know that over-fertilized farmlands and lawns in the middle of the country can lead to dangerous and devastating algae blooms hundreds of miles away killing millions of fish and permanently threatening marine life? The nutrient rich flow fuels the growth of algae and can have a long-term impact on our own fishing and diving industries.

But what danger can a retaining wall along the beach do to the ocean? As the surf hits the coast, it rolls up onto the beach. And as the surf retracts, it takes with it a top layer of sand, incrementally placing it back along the slope of the beach. The next wave comes in and picks up some sand from deeper water and puts it back along the beach. Those walls, and really almost any building close to shore, interferes in the process and causes the beach to disappear as the crashing surf hitting the wall strips the beach of its valuable real estate.

I recommend spending the extra time you will spend in traffic this week thinking about erosion, the role this rain will play, and what you can do to mitigate some of the devastation.