A look at the watershed: After the rain
By Gretchen Messer
Our waters are our most vital natural resource, and water quality is the largest problem. The problem stems from the contaminants that find their way into the water stream. The dirt, trash, bacteria, and toxic chemicals create the consequences of polluted waters world-wide. The World Health Organization claims over 2 billion people on earth do not have access to clean drinking water.
While our world looks blue with water from space, only a minute amount is available for drinking purposes; 97 percent of all water on earth is salty ocean water. Of the 3 percent of freshwater remaining, 2/3 of that is tied up in glaciers and ice. In fact, less than 1 percent of all water on earth is available for our use. Enjoy that cool glass of water as we continue.
We have control of the waters after the rains and after the snow melts. Within a watershed, each drop of precipitation can take endless paths. It can fill ponds and support aquatic plants and wildlife. It can flow down plant stems and roots, infiltrating into the soil where it can replenish groundwater and provide water for vegetation. Here the water is filtered. Nutrients are used by growing plants; sediments and minerals, and the compounds adhering to these particles become trapped in the soil and removed from the waters. Being absorbed into the soils slows rates and decreases the volume of runoff waters.
On the other hand, precipitation can fall on impervious surfaces. These surfaces, such as concrete and asphalt, do not allow the water to be absorbed into the ground. Water landing on these surfaces become runoff, and this is where the problem begins as the water must go someplace. These waters collect, increasing in volume, and increasing in speed as it flows towards the lake. Precipitation landing on roadways, parking lots and walkways, picking up debris and oils, as it flows either directly to the lake via storm drains or indirectly through streams. Some falls on rooftops and into gutters, and down driveways, and ultimately into the drainageways that lead to the lake.
To let natural processes function to filter and store water, it seems that we should be looking at taking measures to enlarge where water can infiltrate the soil, increasing storage times and allowing contaminants to filter out of the water column. Look out your windows and we can all find the areas of our yards that are the wettest. They are small depressions that become muddy. These are also areas that function to retain the stormwater. Be bold and make that depression larger – hold more water. These depressions can be made to look great. More on that in other articles.
We can also alter the man-made surfaces. Reduce the amount of impervious area. This is more difficult as our aesthetics and construction techniques are well established, and much of the land is already paved. There seem to be two options. One, change how we construct our world – add more street trees in parking lots, use different materials for patios, build up instead of out! Two, change what we do with the runoff from impervious surfaces – capture the water in rain barrels, direct the runoff to wetlands, install underground cisterns with new construction.
All of these options and more are viable. These changes involve land owners and gardeners; landscape architects and civil engineers; and architects and policy makers. It will take commitment and a new accepted view of our personal landscapes.
