April 19, 2018

Not your Granddad’s fishing pond!

Looking like cannon-shell craters left over from the Battle of Atlanta, properties all over the metro area are packed with what look like sinkholes bursting with weedy growth. Even the proper term for these repositories of water can be the subject of debate. Some are called “retention ponds”, designed to hold water on a semi-permanent basis. Others are termed “detention ponds”, temporarily holding water following a rain event. At Downey Trees, we like the term “stormwater ponds”, a simpler label that takes all descriptions into account. We know what they are, what they do, and how to make the neglected ones right. Read more about how and why stormwater ponds became a fixture of development in Atlanta and how Downey Trees can help you manage them on your property.

The construction boom of the 1980’s brought with it a massive fouling of our watersheds. Clear-running streams became clogged with silt as increased rushing water from growing areas of impervious surfaces (parking lots, building footprints, roads, sidewalks and driveways) gouged and widened the banks of streams and rivers. Water courses ran “Georgia clay” red with silt from open construction sites unconstrained with proper silt fencing and other protective measures. To give you a sense of how pervasive the problem of silting has become, consider one of Georgia’s largest reservoirs: Lake Allatoona. Since its completion in 1946, silt infiltration has displaced 75% of the water-holding capacity of the nearly 20 square mile lake!

Stormwater ponds were mandated as a part of new development to stem the surge of runoff that flowed off of pavement and gushed into streams after heavy rain events. A variety of structures were engineered for these ponds to gradually release the water in the hours and days afterward. Some devices worked better than others, and some worked more effectively for longer periods of time.

Many detention ponds were seldom, if ever, maintained once they were constructed. Plant succession is characterized in the Southeast by the colonization of bare ground by fast-growing annual and perennial grasses and other plants, gradually replaced by woody plants and shrubs, then fast-growing trees such as Pine, Willow, Boxelder, Sweetgum, Tulip Poplar and others. Plant succession became the norm and guideline for stormwater pond maintenance, despite the fact tree-filled ponds are not conducive to the proper function for which they were originally constructed. Furthermore, those devices inside the ponds designed to regulate the flow of water out of them became fouled with trash, silt, and debris, so ponds became permanent reservoirs of stagnant water, a breeding ground for mosquitoes and other health hazards.

When the economy collapsed in 2007 – 2008, dwindling construction activity resulted in increased scrutiny and code enforcement on infrastructure features such as retention ponds. Due to federal regulations under the National Pollution Discharge Elimination System (NPDES), Engineers and Property Managers were forced to re-examine stormwater management on their properties and bring their facilities up to code, or otherwise face stiff fines. As the economy began to recover in subsequent years, the increased enforcement continued and ground-disturbing activities of new developments were watched closely by the Georgia Soil and Water Conservation Commission (GSWCC), a governmental agency tasked with the protection of Georgia’s watersheds.

For more than 12 years, Downey Trees has assisted building engineers and property managers in bringing the stormwater ponds on their properties back up to code and keeping them that way. Five members of our staff are certified in stormwater management with the GSWCC. Downey Trees staff has more than 50 years of combined experience in vegetation management in and around the ponds, as well as construction, re-engineering and repair of water flow regulating devices and ongoing maintenance. According to our staff, it costs more to clear the weedy growth from an overgrown pond than it does to maintain the same pond on an ongoing basis. The photos show examples of stormwater ponds renovated and maintained by Downey Trees. The illustrations show before and after removal of vegetation, and clearly illustrate the wisdom in managing growth, as well as the potential labor savings in doing this work in the dormant months of fall and winter.

Once control has been restored with regard to vegetation, the next step involves the proper function of both the inflow and outflow facilities of the pond. Water flowing into the pond often carries with it silt and debris. Large granite rock (“rip-rap” or “surge” stone) is often used in a weir (elevated check dam) to catch the debris coming out of inflow pipes, as well as to filter the silt. Debris and silt most always has to be removed from the pond following the vegetation, and clean filter rock installed. Attention then turns to the pond’s outflow devices. These may be composed of permanent concrete outflow regulators or semi-permanent devices composed of rock and metal grates. Our staff has expertise in determining the exact needs of a pond to restore its proper function.

When the pond has been restored effectively, ongoing maintenance is a wise economic consideration. So often, we have seen a significant investment in stormwater pond restoration completely squandered by several years of repeated neglect. In some instances, just a season of re-growth in and around a pond can double or triple the cost of a regular maintenance program. One of the highest cost factors in pond restoration is tree removal. Many, if not most, municipalities do not allow trees in the functional area of a stormwater pond. If trees are allowed to overtake a pond, their removal can add thousands of dollars to renovation costs. Maintenance frequencies are another potential pitfall: trying to save a few dollars by cutting out a maintenance service or two in a season can end up costing far more in vegetation removal if a season is particularly conducive to re-growth.

Whether your stormwater pond is a part of your homeowner’s association, condominium, commercial property, or a client’s property, Downey Trees has the certification, staff, equipment, and knowledge to provide turn-key service for the restoration and maintenance of those under your care. Contact us for a review of your pond and a quote for corrective measures. While it may not be as enjoyable as your Granddad’s fishing pond, your stormwater pond is an essential asset to your property. Proper care and management can prevent serious problems, expensive corrective measures, and potential fines.

April 19, 2018