Reduce Runoff

Image by Douglas Kent

Changing surfaces, like concrete (mostly concrete), has two big benefits. First, permeable surfaces increase infiltration, reducing runoff. And second, it slows water. Concrete is considered a fast surface, whereas permeable surfaces, like pavers, decking, and decomposed granite, are considered slow. And the slower runoff moves, the better. Slow water lacks the power to hold onto debris and heavier pollutants.

Changing surfaces can be expensive, or not. Removing a driveway and replacing it with pavers is not cheap (up to $10,000). On the other hand, decking and decomposed granite are cheaper than pouring concrete. A proven technique for cutting costs and adding value is cutting the driveway, taking out chunks and putting in drain grates, rocks, and/or plants.

A landscape planted with shrubs and trees can handle 30% to 50% more rainwater than turf. Makes sense, though: there is more foliage, more roots, and more need for the rainwater. And opposed to turf, most shrubs and trees require less ocean polluting fertilizers and pesticides, while providing refuge for more birds and beneficial bugs.

Parkways are perfect areas to capture runoff. The water in these areas will not endanger the house. But because of the heavy public interaction - the people offloading their cars, the dog walkers, and children running through them - they are tough to design. Use the illustration below to create your own Pacific protecting parkway.