What does the water standing in your backyard after a rain and the pending severe floods in North Dakota have in common? They are both the result of stormwater. Having lived in both Louisiana and Florida, I know full well the devastating affects of the floods threatening our neighbors (albeit it distant) in North Dakota. Please keep them in your thoughts, and if help is requested, I hope that all who can will help out. For some of the less noticeable affects of stormwater, enter stage left: Wikipedia.
I do so love Wikipedia:
Stormwater: "...is a term used to describe water that originates during precipitation events. It may also be used to apply to water that originates with snowmelt or runoff water from overwatering that enters the stormwater system. Stormwater that does not soak into the ground becomes surface runoff, which either flows into surface waterways,[sinkholes and other karst features], or is channeled into storm sewers.Stormwater is of concern for two main issues: one related to the volume and timing of runoff water (flood control and water supplies) and the other related to potential contaminants that the water is carrying, i.e. water pollution." Based upon that definition, it is clear that there are two key components of stormwater, quantity and quality. A large quantity of reasonably clean stormwater or a small quantity of polluted stormwater can each do a tremendous amount of damage. Clearly, it is as important to be able to anticipate problems with both quantity and quality in land use decisions.
Every square inch of asphalt or concrete represents the loss of pervious surfaces that will allow rainfall to be absorbed into the ground. This means that more water runs off of that surface, adding to totals in other areas. If the rainfall is fairly light, the additional water may well be absorbed by surrounding soil. In situations where the rainfall is heavy , the soil cannot absorb it quickly enough, and it simply cascades down slope until it reaches the lowest possible point, where it sits until it can be absorbed. That spot where the water sits could be your backyard, a man-made retention pond or lake, a ditch, or it could run into a stormwater drain, a creek (or other natural water source), etc.
Most people will notice if there are a couple of inches of water hanging out on a water-type vacation in their backyard. Some will even notice that levels in local waterways seem to be elevated or the water is moving a bit faster than usual.What goes unnoticed by many is what that water may have picked up in its travels and the slow erosion of soil that can occur over time.
Whatever heavy metals (zinc from parking lots and roadways), chemicals, bacteria, organic fertilizers (poop to many of us), petroleum-based products, bits of soil, etc. that the water passes over in it travels can be picked up and carried by the water. All of those little bits and pieces hold a 'meet and greet' where ever the water pools. Some of it gets sidetracked along the way, leaving small samples along the entire course of the water. But, the bulk is carried to that backyard, ditch, creek, pond, etc.
Unless the area where the runoff is deposited is a moving body of water, the various items picked up will accumulate over time, sometimes growing to levels that create a hazard to various lifeforms including humans. The areas where filtration down into the soil is particularly slow, you have the added bonus of providing a breeding ground for mosquitos which can, an often do, carry diseases which can be transmitted to humans and animals. As solids settle to the bottom, the area where the water stands become larger in surface. (If you want to test that theory, take a small bowl of water, fill it to the brim, then add a handful of sand to it. Please be sure you do not try this around electrical appliances:)
If the recipient of that runoff water happens to be a moving body of water, only the heaviest of particles will settle out in the early stages. It will not be until the size of the stream increases and the flow slows down some that more of the particles will filter out. This could mean that those same types of deposits settling in someone backyard could show up hundreds of feet or miles away. Those deposits, along with the deposits from other steams, come together and become part of some of our major food source systems: the water is used for irrigation, provides habitat for fish and seafood, and enters the drinking water is provided to homes.
Maybe all of this sounds a bit off topic coming from someone who usually comments on local government and laws. Well, it seems to me that stormwater quality and quantity should be a top issue for our local government. Land use decisions made by our local officials can have far reaching affects. It is important to see that people's backyards are not flooded. It is also important to make sure that the water flowing from areas of impervious surfaces is as safe as possible. In the long-range view, both quality and quantity of stormwater are important to our futures and for generations to come. There is no reason why we have to accept the minimum state standards. We can and should do more.
No matter how much 'green space' we have, if we do not make efforts to effectively monitor and manage stormwater run-off and improve stormwater protection methods, those green spaces will simply become repositories for all of those chemicals, biological organizisms, etc. and simply become toxic areas.
As usual, these are just the opinions I arrived at after doing a lot of reading. I'm sure there are plenty of readers out there who know more about the subject than I do. These may seem like pretty small things when compared to the problems note in a recent Roanoke Times article about the
Radford Arsenal's claim to fame as the largest polluter in the state for the second year in a row. Despite the fact that the pollution levels are well below the allowed criteria, it is noted in the article that those responsible at the Arsenal are serious about taking steps to reduce it even more. Perhaps we, as individuals and as a Town, could try to do the same thing and no longer accept the minimal state standards as the standards for Christiansburg. The Town can adopt more stringent guidelines for stormwater management. We can learn more about the chemicals we use on our lawns and gardens, how we dispose of chemicals (gasoline, diesel fuel, paints, etc.), and maybe even where brick and mulch patio area might work as well as solid concrete.
oh...shoot...so many things to learn about..and so little time.... If the Town had higher standards and each of us did one thing to help to either prevent stormwater runoff or improve the quality of stormwater escaping from our properties and neighborhoods, it could make a big difference for us, our children, and our grandchildren.
Some informative links (I do not necessarily agree with everything contained in these documents, but that are good starting points for building the foundation of knowledge required to understand stormwater issues. There are a lot of other sources of information at your fingertips using Google.):