Flooding

Although we’ve been in a drought for quite some time and there is a good chance it may continue, areas of our neighborhood still experience extreme flooding even during moderate rain. The reason for this is that there is too much impervious surface – roads, parking lots, roofs, and driveways – and too little mitigation of runoff in our watershed basin. Under natural conditions, the soil and vegetation can absorb enough water so that it percolates slowly over time into the creeks. As a result of overdevelopment and/or inadequate stormwater management, too much of the water from rainfall goes directly into the streams and creeks through the storm drains. That causes flooding of low-lying properties, not to mention trashing, erosion, sedimentation, and polluting of the streambeds. So, apart from the losses to property owners as well as tax payers who pay for FEMA buyouts, other side effects impact everyone’s quality of life. They include flooding of parks and greenspaces, loss of trees that fall into the creeks, invasions of non-native species like privet that fill in the gaps, and loss of the small fish and other aquatic life on which wildlife like birds and mammals depend. Our neighborhood lies about two thirds of the way downstream in the South Fork Peachtree Creek Watershed. That means that a large portion of the water from rain falls upstream of us. And because unfettered commercial and residential development has been allowed in the upstream areas as well, the rain water becomes a tidal wave by the time it reaches us. Click here to see a map of the watershed, including the major streams and a satellite image overlay showing impervious surfaces. Can anything be done? Although it would have been easier had there been adequate stormwater ordinances before all the development occurred over the last fifty or sixty years, there are opportunities to retrofit commercial, residential and public properties. Redevelopments offer us the opportunity to have large commercial properties retrofitted with stormwater structures that reduce run off from their parking lots and roofs. They are required by county ordinance now to manage stormwater from the site. In addition, we could also ask them to consider grass pavers for parking or some other innovative ways to reduce impervious surface. Commercial enterprises get a break on the stormwater utility fee if they reduce impervious surface. Runoff mitigation at these sites could have huge impact. Take a look at some of the developments/redevelopments in our area here. Please consider attending meetings or sending emails or letters to our commissioners. Neighborhood streets and yards. Almost all stormwater runoff from roofs, driveways, and roads goes straight to our creeks via storm drains, carrying with it any trash in the street as well as yard and vehicle pollutants. A neighborhood campaign – perhaps in coordination with upstream neighborhoods – could help mitigate this with street clean ups to remove trash before it goes into the creeks, rain garden and rain barrel promotions to catch the rain from our roofs, and tree plantings. Tree leaves, branches, and trunks catch a lot of rain and it is helpful to have them reach out over roofs, driveways, and roads. By the way, if you observe that a storm drain needs cleaning out, you can call the county at 311. They should put you through to the Roads & Drainage department who will send someone out to inspect it and schedule a cleaning or repair as needed according to their assessment of its urgency. Public Spaces. Many of our parks are honeycombed with compacted dirt trails, not to mention dirt areas used as parking lots. Our heavy clay soil under compaction becomes nearly as impervious as concrete. The Parks department will soon begin asking for public input on a new set of master plans for the parks. It would help to have them to plan for AND implement some sort of trail and parking management system so that vegetation is protected and runoff minimized. The community can also push the county to implement restoration of streambanks using natural materials as well as installation -- again with natural materials -- of stormwater detention ponds along the creeks. It has been done in other parts of the country. Why not here?