Location: Decatur, Georgia, DeKalb County
Title: A Suburban Creek Resists Channelization

A visual examination of Doolittle Creek in a highly developed suburban county in Georgia yielded telltale signs of a creek whose original streambed had been altered. Examination of official county maps dating back to the mid-1920s and aerial photographs gave further evidence of alterations that had been made. A county historian with a lifetime interest in county development added verbal accounts of changes that had been made. These three forms of evidence indicated that with the building of subdivisions beginning after the 1920s and continuing to the present, this creek was indeed channelized to accommodate the development of single-family housing developments and shopping centers. Prior to this development, this area was home to dairy farms, some schools, and Prison Honor Farm #2.

Today portions of the streambed are unnaturally straight. Although historical documents do not show records of measures taken to straighten this stream, maps show that downstream from the area of interest, large meanders were completely removed to accommodate development. Due to the apparent channelization of this creek, the water velocity is unusually swift. Water flowing around barriers in the creek is causing considerable damage and is undermining the banks in the area. The most obvious results are several examples of severe erosion in the streambed that have uprooted trees along the stream bank. Sediment deposits are evidence that the stream is reestablishing meanders that were removed during the channelization process.

Interest in the creek’s problems began when faculty from a two-year college, along whose property the creek passes, joined the County's Adopt-A-Stream program. Faculty and students have carried out monthly water monitoring exercises since August of 1998. In June of 1999, on three separate occasions, members of the Adopt-A-Stream program, the newly formed Doolittle Creek Watershed Alliance, and the Southeast Waters and Outward Bound organizations walked the most severely impacted section of the creek and recorded stream data. When this data was shared with college faculty who were already interested in the creek’s water quality, a decision was made to explore the possibility of restoration of this portion of the creek to a more natural state.

The goal of this project is to promote among students, teachers, and members of the community the concept of a healthy watershed as one of the keystones of a healthy environment. The faculty member who initiated interest in the creek wrote a proposal. An EPA Educational Grant proposal was written, outlining the benefits to both the college and the community of undertaking a project of this type. The plan, with photographs, was presented to the college on whose property the creek runs.

KEY PRINCIPLES RELATED TO THE CASE

1. Erosion is a process or a group of processes by which loosened material, as well as material not yet separated, is dissolved, loosened, or worn away from one part of the earth's surface and deposited in other places. Streams are the most important agents of erosion; they operate everywhere on earth except in the polar regions to produce ordinary valleys and canyons and may form deltas where streams flow into lakes and oceans.
2. As surface water flows downward toward streams, rivers, and ultimately lakes or the sea, three zones can be identified. The headwaters form the first narrow zone. The water is relatively turbulent and consequently has a higher content of dissolved oxygen.
   As the waters move into the second zone, the streambed is wider and the velocity of the stream decreases. The streambed develops more meanders as it moves more slowly across broader and flatter areas.
3. Channelization of streams consists of straightening, deepening, widening, clearing, or lining existing stream channels. It is an engineering technique that has been used to control floods, improve drainage, control erosion, and improve navigation. Adverse environmental effects include:
   • degradation of stream's hydrologic qualities, turning a meandering stream with pools and riffles into straight channels;
   • removal of riparian vegetation, which removes wildlife habitats and shading of water;
   • downstream flooding where channelized flow ends;
   • damage or loss of wetlands; and
   • aesthetic degradation.
4. In the present case, we are considering a stream whose watershed encompasses about 12 square miles in the Piedmont region of Georgia. The gently rolling terrain would not support rapidly moving streams characteristic of river headwaters. Over this relatively small area one cannot observe much change in altitude. However, one can imagine that the region of interest, as close as it is to the point where it merges with a large river, had developed meanders over time. Information was gathered from a set of maps produced by the U.S. Coast and Geodetic Survey and the City of Atlanta Mapping Division. The survey, performed in 1928, showed many more meanders than the version shown in the 15^th edition of the ADC Atlanta and DeKalb County Map Book.

ETHICAL CONSIDERATIONS RELATED TO THE CASE

1. Doolittle Creek is a part of a much larger South River watershed. It flows south into the South River about three and one half miles after its origin. South River has its own problems with erosion and both point and nonpoint pollution. There is extensive runoff from large areas of paved surfaces and sediment from upstream development. It is necessary to attempt to correct upstream problems as well as tackling the much larger problems down stream.

Figure 1

Aerial photos reveal that the stretch of the creek of concern is considerably straighter than other stretches. It is possible that the channelization might have been an attempt to facilitate the building of subdivisions to the north, and ball fields and parking lots to the east and west. Whatever the purpose, the channel in its present state has been gouged out by the more swiftly moving water in the mostly U-shaped channel. The streambed ranges from 20 to 50 feet wide and is 8 to 14 feet deep. Each visit provides more evidence that the erosion (Figure 1) is undermining trees and other vegetation growing along the banks.

This severely impacted part of the creek begins at a bridge that runs east to west over the stream. This bridge rests on three cement box culverts. The June 1999 inspections of the creek found that silt carried by the stream had nearly filled one culvert and had partially blocked another, leaving only one culvert available for the creek's passage. At that point the water was about 1 foot in depth with 8 inches of sediment in the streambed.

Figure 2

Adding to the original man-made changes to the streambed is the current practice of mowing the grass to the edge of the stream bank. The possibility of establishing a riparian buffer is undermined by this practice. Two sewer lines in this area cross the creek. Culverts dump storm water into the creek at three locations south of the bridge. A footbridge crosses the creek just north of the first storm water culvert. A collapsed dam can be seen south of this area; here there is even greater evidence of the stream's efforts to reestablish meanders around sediment islands that have formed (Figure 2).

2. The stakeholders in this study are the landowners adjacent to the stream. Much of this land was publicly owned during the 1920s. Land to the east of the creek belonged to the Prison Honor Farm and schools. It has been developed by state-owned facilities: Georgia Regional Hospital, the Georgia Bureau of Investigations, a juvenile correction facility, DeKalb County Schools, and Georgia Perimeter College. DeKalb County Schools and Georgia State University use land on the west bank. DeKalb Parks and Recreation and Roads and Sewers also have an interest in the protection of the watershed. Land on both sides of the affected area of the creek is under the control of Georgia Perimeter College.

Plans to restore the natural meanders of this watershed have been presented to college administration officials and they have given approval for the project. The much larger South River Watershed Alliance has given its support to the plan. Leaders who have been active in restoration of other local watersheds have examined the situation and given advice about solutions.

3. The entities that would carry out the restoration project would be both private and volunteer. Financial support will come from grants for which applications have been made. Private individuals with experience in stream restoration would lead the effort. Other support would come from interested volunteers who have been involved since inception of the plan. No county department will be using its funds to complete the work. No need for legislation or this project is visualized.

CONCLUSION

The citizens who are interested in this project anticipate that increasing interest shown by the surrounding community will intensify as a result. The watchful interest of these citizens will be required to monitor the day-to-day erosion problems that are a consequence of development. Perhaps they will call for more legislation designed to either hold development in check or more adequately control how development proceeds.

Author
Dr. Catherine Carter
Georgia Perimeter College