Have you ever wondered why a torrential rain falling up near Chatsworth and Dalton can cause the Oostanaula River to rise dramatically even though we never got a drop of rain in Rome?

Why does the Etowah River run clear and low after heavy rains in Canton and Dawsonville, yet the Etowah will turn extremely muddy after a heavy rain in Rockmart? Why does a heavy rain in Cedartown not affect the rivers in Rome at all? It all boils down to the nature of the watershed.

Watersheds, also known as drainage basins, are natural, funnel-shaped areas defined by hills and mountain ridges in which all rainfall flows downhill into the nearest stream, creek or river. These watersheds can be large or small.

The Horseleg Creek basin is rather small, about 6 square miles, and includes almost all of West Rome north of Mount Alto and south to the railroad tracks that parallel Shorter Avenue.

Silver Creek basin is larger, about 40 square miles, originating in North Polk County and encompassing everything between highway 27 and highway 101.

The drainage basin of the Oostanaula River is quite large and begins in the Chatsworth and Ellijay area and includes most of five counties.

The Connasauga River is one of the main tributaries of the Oostanaula and flows un-impounded from its headwaters to the confluence with the Coosawattee at Calhoun. The Coosawattee has a dam, Carters Lake, which controls the flow from the high mountains at and near Ellijay.

The Etowah basin is a little smaller than that of the Oostanaula and the flow from the Etowah is controlled by Allatoona dam before getting to Rome.

In these recent months of above normal rains, it is important to understand water basins because, even if there are heavy rains many miles from your house, if that rain is within your basin and the ground is saturated, you might just have flooding at your house. Even though the Horseleg basin is small, much of the surface of the basin is prone to quick run off.

I would estimate that a fourth of the surface within the basin has been paved or has homes or buildings which just shed the water into the streets and storm drains.

The result of the quick run off is that the stream fills to overflowing quickly and a heavy downpour can cause a flash flood.

Silver Creek on the other hand has very little impervious surfaces and the flow into the stream is not nearly as quick. It takes a lot more rain to get Silver Creek to flood stage than it does Horseleg.

The steepness of the terrain also affects how water levels within a basin react. Mountain streams such as Holly and Mill creeks which flow off the west slopes of the Cohutta Mountains have small basins that are located in steep mountains and the water will rise very quickly.

The run off in these mountains is swift letting the stream return to near normal levels quickly. Armuchee Creek has a much larger basin and it has headwaters in the mountains also.

Armuchee Creek rose about 15 feet in about 36 hours from the rains on the Nov. 10 and has only dropped about two feet as of this writing on the Nov. 13.

Holly Creek on the other hand rose 7 feet in 18 hours and has dropped five feet as of today. Armuchee Creek basin is so much larger and less steep than Holly causing the mountain run off to take a lot longer to drain.

In a few days Holly will be back near normal and Armuchee will still be extremely high.

The next time we are in a rain event whether heavy or light, pay attention to the weather radar. If you know which creek basin you are in and even though it may be raining nearby, unless it rains in your basin the creek should not rise.

Johns Creek

About a dozen and a half TU members and other volunteers spent several hours grooming the creek banks and road sides at Johns Creek. A lot of trash was removed, fire rings were broken up and the creek is a lot better off thanks to our efforts. The Department of Natural Resources intends to make more progress in the next few months to make the creek a better place to fish and more family friendly.

Trout Meeting

The next meeting of the Coosa Valley Chapter will be Thursday, Nov. 19 at 6:30 p.m. at Fuddruckers in Rome. This meeting will recap the Chili Cook Off. Also, this is the annual meeting in which we have elections of officers and board members. The public is invited and our members are urged to attend.