By: Jake Donellan, BMP Forester (Ret.), Texas Forest Service
Q: If you leave a buffer strip on ephemeral drains, do you treat it as a Streamside Management Zone (SMZ)? A landowner asked me that question this past weekend and I didn’t know the answer. My buddy suggested that I send this question in to see what you would recommend. What do you think?
A: That is an excellent question. Ephemeral drains can often times be very difficult to deal with. I am sure most of you know the difference between the three classifications of streams but I would like to review them for those who may have forgotten. The three classifications of streams are perennial, intermittent, and ephemeral streams.
Perennial streams are streams that flow throughout the majority of the year (90% of the time or greater) and flows in a well-defined channel. Intermittent streams flow mostly during the wet periods of the year (30-90% of the time) and flows in a well-defined channel. Ephemeral streams or drains flow only during and for short periods following precipitation and flows in low areas that may or may not have a well-defined channel.
The Texas Best Management Practices “bluebook” recommends an SMZ, with a minimum width of 50 feet on either side of the stream channel, on all perennial and intermittent streams. Buffer strips on ephemeral drains are left up to your professional judgement. Your experience may tell you that you need a buffer strip on an ephemeral drain to keep it from washing out and becoming an erosion problem. However, the recommended guidelines do not treat buffer strips on ephemeral drains in the same manner as SMZs. I would simply say that you should use your professional judgement here as to how to treat the buffer strip. I would look at the soil type and slope to determine the width of my buffer strip. On a steep sandy soil, I might treat the buffer strip very similar to the way I treat an SMZ. However on a clay soil with moderate slopes, I would probably have a narrower buffer strip. I would also try to keep the channel free of tops and debris, and avoid crossing the drain if practicable.
The ball is really in each of your courts in circumstances like these. This situation is one of those areas that can really make the difference for us (the forest industry as a whole) in our efforts to keep BMPs non-regulatory. Good, prudent decisions can help us all look that much better to our critics.
I hope that answered your question. Does anybody else have any other suggestions or methods that they use? Thanks to your buddy for suggesting that you give me an opportunity to make some recommendations. I always appreciate the opportunity to address specific BMP related questions.