Friday, November 1, 2002

November BMP Q&A

By: Hughes Simpson, BMP Forester, Texas Forest Service
Q:   The other day, I read the executive summary of the BMP report that you have been mentioning in this article the past two months. I saw that there were two major deficiencies noted in the evaluations. Could you explain these “problem areas” in greater detail?

A:   Sure! The report “Voluntary Implementation of Forestry Best Management Practices in East Texas, Round 5” noted two major deficiencies in the evaluation of 150 forestry sites from August 16, 2000 to April 23, 2002. The first area of deficiency was improper stream crossings on temporary roads. The second area of deficiency was the high amount of significant risks to water quality that were noted. This month, let’s concentrate on the first deficiency.

Stream crossings are generally an area of concern because they have the potential to contribute a large amount of dirt to a stream. When these structures are not installed properly and without using BMPs, water quality may become impacted. The report primarily identified stream crossings on temporary roads, but crossings on permanent roads can cause similar problems.

These structures can be expensive to install and maintain, costing you both time and money. With proper planning, you might decide that crossing a stream may not be necessary. Aerial photographs, topographic maps, soil surveys, and on the ground field evaluations are excellent tools that can help you make these decisions. Going around the head of streams can also be a very effective and practical way to access the other side.

There are many situations when you have no other option but to install a crossing. The key is to minimize the amount of dirt that enters the stream. Dirt crossings should never be used. Logs or brush placed lengthwise in the stream channel can serve as good alternatives, as long as they are removed when the operation is completed. Drag line mats and “Arkansas bridges” also work effectively. If you decide to use a culvert, make sure it is properly sized and that you have the equipment to remove it and the fill dirt when the operation is finished.

Whenever you are putting in a crossing, find the straightest section of that stream and cross it at a right angle. This will help to minimize bank disturbance and reduce the amount of sloughing that occurs. It is also important to stabilize the approaches with grass, rip-rap, or other erosion control materials to ensure a stable roadbed approach and reduce the amount of dirt entering the stream.

Since the inception of the BMP monitoring program, stream crossings have always been a thorn in our side. We have made great strides over the past 10 years in installing these structures. This progress is best noted by the increase in BMP implementation ratings on stream crossings from Round 4 (67%) to Round 5 (85%). However, there is still plenty of room for improvement in these areas. If you have a question regarding BMPs, please call me at (936) 639-8180.

* This article was published in the November 2002 issue of the Texas Logger

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