Since the earliest civilizations, societies have wrestled with a love/hate relationship with the “almighty agua.” We are no exception. In countless ways, we are absolutely dependent on this magical and ever-changing substance.
Water fills our cells, flows through our veins and in short, enables us to live. Yet water can also bring us severe hardship, destruction even death. Through floods, landslides, disease and drowning, water is capable of swallowing us whole, as though reclaiming the life it once so generously nurtured.
Coming to terms
Today, our struggle with water continues. In a nutshell, we love water, but we especially love having control of it. We cherish our pools, yet curse the wet spot in our yards. We hook up our sprinklers, yet bemoan our leaking basements. We pray for rain, yet dam the floods.
And we scratch our heads when we realize there’s a storm water basin on our property. “A what?” you ask. A storm water basin. Though often unnoticed, and more frequently deemed an eyesore, these peculiar ponds actually have a purpose. In fact, their functions are far more important than adding aesthetic value to your yard.
So before you are overcome with the will to fill it or the desire to drain it, let’s try to come to terms with this structure called a storm water storage basin or storm water pond.
Just what are they? What do they do? And what do they want from you? As we develop our communities, we change the land and how we use it. Land cover is often converted from trees or grass, to rooftops, driveways and parking lots. During a rain event, the storm water runoff now has less ground surface to infiltrate or be absorbed into.
Pollution carrier
Storm water runoff is one of our most common causes of water pollution and is caused by the daily activities of all of us. Rainwater and snowmelt runoff from streets, lawns, farms, construction and industrial sites pick up fertilizers, dirt, pesticides, oil, grease and many other pollutants on the way to our rivers and lakes.
Anything that enters a storm sewer system or ditch is discharged directly into local streams and eventually into the Ohio River Watershed or into Lake Erie.
To manage the quantity of storm water generated from development, the design engineer compares the pre-development and postdevelopment volumes of runoff. If designed and maintained properly, the function of a storm water pond is generally to discharge runoff at the predevelopment rate.
For example, storm events in our region are characterized by the amount of rainfall (inches) received in a 24-hour period.
Keep in mind that a 100-year storm event could happen once, twice or several times during our lifetimes. A 100-year storm event has a 1 percent probability of being equaled or exceeded in any one year, whereas a 5-year storm event has a 20 percent probability of being equaled or exceeded in any one year.
Improvements
Years ago, storm water basins were designed to address only runoff quantity. The emphasis was on storage, flood control or prevention and downstream erosion. Newer emphasis and strategies have begun to incorporate water quality parameters such as temperature, oxygen content, pH, organic and suspended solids, turbidity, salinity, nutrient and pesticide levels.
Basics
There are several types of storm water basins or structures for managing storm water. These include bioretention swales, infiltration trenches, wetlands and dry and wet basins, among others. Geauga County has more than 500 storm water structures.
The Geauga Soil and Water Conservation District conducts an annual storm water basin inspection program, where individual basins are generally inspected and evaluated every three years to ensure they are still functioning as originally designed.
Storm water basins are generally designated as either a detention or retention facility. A detention basin is generally for the short-term detention of storm water. A dry detention basin is designed to empty within 6 to 12 hours after a storm, while extended detention dry basins may lengthen the storage time to 24 or 48 hours.
Longer storage times tend to result in improved water quality because additional suspended solids are removed. A retention basin, also known as a “wet pond,” includes a permanent pool of water, and is typically designed to protect water quality. Water is released only through percolation, evaporation, transpiration or an emergency overflow.
In essence, storm water ponds hold, store, and filter water. Sound familiar? Think back to those acres and acres of Ohio wetlands that once covered our state but are now filled, drained, or paved.
Maintenance
The idea of having a pond is often attractive to homeowners … until it comes to maintaining it. Monthly and annual maintenance responsibilities include inspections and light housekeeping duties.
Monthly duties are often mowing and debris and trash removal. Annual responsibilities include inspection and repair to the physical components of the basin, including erosion. All of these duties should be identified, assigned, and documented.
In Geauga County, for example, storm water basin ownership and subsequent maintenance and repair responsibilities are established legally by recording two documents with the Geauga County Recorder. One is an Inspection and Maintenance Agreement (I&M) and the other an “as-built” drawing, verifying the storm water facility was constructed according to the approved engineering design.
Basin ownership may take one of three forms: The basin is owned by the individual lot owner on which it is located, the basin(s) is collectively owned by all the resident members it serves (i.e., Homeowners Association) or ownership and maintenance of the storm water facilities are transferred to the county engineer through a Drainage Maintenance District agreement.
Basin makeovers
May a storm water basin be altered or modified? Yes, as long as the original design objectives and control functions continue to be met. Start by contacting the agency that designed and approved the basin before making any changes.
The new proposal must be designed by a professional engineer and submitted along with revised storm water calculations. Geauga SWCD requires prior written approval and receipt of a revised “as-built” within 60 days of project completion.
No matter where we live, our storm water basins are working hard to perform many critical functions, including reducing storm water runoff from our neighborhoods and improving its quality before it enters our streams, rivers, and drinking water sources.
Storm water basins are vital to protecting public and private property, public health and safety, and water quality, but only if they are functioning properly.
Let’s do our part to enable storm water basins on our property to do what they were designed to do for as long as they can do it. Let’s maintain them and sustain them. Let’s remember that storm water basins create cleaner, clearer water for today and for future generations tomorrow.
And as for wrestling with the water? Up here in Geauga County, we’ll let the storm water basins do their own part. Soon enough, we’ll be too busy plowing snow.
(This article was collectively written by Bob Griesmer, district technician; Gail Prunty, natural resources specialist; and Carmella Shale, district engineer/administrator of the Geauga Soil and Water Conservation District.)
