The Atlanta Regional Commission has responsibility for:
Metro Atlanta's Water Story
Our water comes from rivers, streams and reservoirs. In fact, 73% of the water supply for the 15 counties of the Metro Water District comes from Lake Lanier and the Chattahoochee River. The rest of the water comes from the Etowah, Flint and Ocmulgee Rivers.
And although we get an average of 50 inches of rain per year, there are limits to what we can use.
What’s more, the rivers that supply our water are relatively small because we are located near the headwaters, or origins of the streams. We can only draw so much or we’ll damage the ecosystem, so we depend primarily on our big regional reservoirs – Lake Lanier and Lake Allatoona – for most of our water.
Then, there’s that giant hunk of granite and granite-like rock under the region. Stone mountain is awesome, but the part sticking out of the ground is only the beginning. Georgia’s beloved rock, or other rocks like it, extends under a large part of our region, seriously limiting the amount of water that can be withdrawn from the ground. Ever tried to squeeze water from granite?
Conserving water something we need to do year-round.
A watershed is the area of land that drains to a common waterway, such as a stream, lake, estuary, wetland, or even the ocean. We all live in a watershed.
Watershed areas that drain to major rivers are typically called river basins and are made up of many smaller watersheds. In the Atlanta region, there are five major river basins. Three of these, the Chattahoochee, Flint and Coosa river basins eventually flow to the Gulf of Mexico. The other two, the Oconee and Ocmulgee drain to the Atlantic Ocean.
Assesing the entire watershed is important in addressing pollution as well as protecting drinking water supplies. Effective watershed management is key to protecting and preserving the Atlanta region’s quality of life and economic vitality.
The Stormwater Runoff Problem
After it rains, some of the water runs off the land, rather than soaking into the ground. This stormwater flows downhill to the nearest storm drain, stream, river or lake.
In an undeveloped watershed, most of the rain is absorbed into the soil and taken up by vegetation, with only a small amount of runoff occurring. As a watershed is developed, impervious surfaces such as buildings, parking lots and roadways prevent rainfall from infiltrating the ground. This results in increased stormwater runoff which can cause flooding and stream bank erosion.
In addition, stormwater runoff picks up a number of pollutants as it flows off of rooftops, lawns, streets and parking lots. These contaminants include sediment (dirt), leaves, grass clippings, fertilizers and pesticides, oil and grease, litter, heavy metals and animal waste. All of these can cause water quality problems in the receiving water body.
Addressing Stormwater Problems
Communities in the Atlanta region are addressing these issues through watershed and stormwater management. This involves a number of programmatic activities designed to mitigate the impact of stormwater runoff problems including requirements for new development projects, effective erosion and sedimentation control, floodplain management, pollution prevention, illicit discharge elimination and stormwater system inspection and maintenance.
The Georgia Stormwater Management Manual, an ARC effort, provides guidance on stormwater management policy, technical design standards and pollution prevention with the goal of reducing stormwater impacts to our communities and shared water resources.