Outfall Protection

What exactly is outfall protection?  Outfall protection is an essential element of proper culvert installation and can certainly extend the life of your culvert.  Outfall protection most often consists of rip rap or other large aggregate placed at the end of the culvert to intercept and absorb the energy produced by the water exiting the culvert. 

Rock Outfall Protection

As water flows down a ditch or stream, it is gaining speed or velocity.  This velocity increases once the flow of water is concentrated in a culvert.   Culverts also tend to have more smooth edges, or less roughness than the ditch or streambed to slow this water down.  Once this water exits the culvert, it is moving relatively fast with lots of power ready to move some soil and cause erosion.  In addition to scouring out the channel down from the culvert, this water tends to swirl around as it leaves the culvert and can eventually wash out the culvert, costing you money to come in and re-install your culvert. 

Outfall protection intercepts this flow and spreads it out, thus reducing the speed of the water and its erosive power.  Outfall protection can be as simple as some old bricks, busted up concrete, old tires, or large rock.  On cross-drain culverts, where you are transferring runoff from across the road, you may want to not only put outfall protection under the end of the culvert, but also on the bank adjacent to the culvert exit, to help preserve the bank and prevent excessive erosion.   On culverts used for creek crossings it is often important to not only have outfall protection on the culvert exit, but also on the sides of the banks on either side of the culvert exit.  This will prevent swirling water exiting the culvert from eroding the stream banks and eventually blowing out the sides of your culvert. 

Outfall protection can also be an important component of wing ditches on some of your woods roads that are generally only used during forest operations.  In these instances, you may not need to invest in large, rock aggregate, but instead can prevent excessive erosion by placing slash or brush at the outlet of the wing ditch.  Another method of providing outfall protection on wing ditches could be using vegetation.  If this is an area that doesn't receive a large amount of runoff, it is a good idea to use our seeding chart on page 67 of the blue book. 

In conclusion, outfall protection is essential in protecting your culvert, ditch, stream, wallet, and water quality in general.  Outfall protection will save you money by not having to re-install culverts and reduce the frequency that you have to come and pull your ditches.  Outfall protection protects streams health and preserves water quality by reducing the amount of sediment traveling downstream that result from stream bed and stream bank scour.  

May 2013 BMP Q&A

By: Todd Thomas, Water Resources Forester, Texas A&M Forest Service

Q:  One type of temporary stream crossing that I have heard mentioned, but never seen or even heard discussed in great detail are PVC bundles.  What exactly are these and how can I construct my own?

A:  Excellent question about an innovative stream crossing method.  PVC bundle crossings can be constructed relatively cheap from readily available materials and can be re-used and repaired without issue.  While not suited for large streams, PVC bundles can be used on most ephemeral and intermittent streams with a U-shaped profile that are not more than 10-feet wide and 4-feet deep in channels with low flow.  Think of these bundles as a large handful of straws. 

In order to create a 12-foot wide pipe bundle that is 16-feet long when laid flat, you will need 12 20-foot joints of 4-inch diameter schedule 40 PVC pipe, four 18-foot lengths of 3/16 inch galvanized steel cable, and eight 3/16 inch cable clamps.  The 20-foot joints of pipe should be sawed into 12-foot sections with the remaining eight feet sawed in half so there are two 4-foot joints, per 20-foot joint of pipe.  Next, drill ¼ inch holes completely through the 12-foot long joints at locations 2-feet and four-feet from either end; on the 4-foot long joints, 2 ¼-inch holes should be drilled, each 1-foot from the end.  Alternate one 12 foot long joint with one row made of two 4-foot wide joints placed 2-feet from each other.  Finally, you will connect the joints of pipe.  To do this, string each strand of galvanized cable through the holes in each joint of pipe.  Once strung through, make loops on the ends of each cable and secure them with the cable clamps.  Each cabled section should be loose so pipes can conform to the stream channel.  When you are done there should be 2 4-foot sections of PVC remaining, these can be used at your discretion.   

In order to utilize your newly constructed bundle, begin by lying on end of the pipe bundle at the top of the bank and allow the rest of the bundle to lie in the stream channel slowly piling it back on top of itself.  The ends of the bundle should be resting on banks opposite each other.  The loops in the cable can then be used to tie off the bundle to anchor points on each side of the stream.  You may want to lay boards across the bundle perpendicular to allow for better traction when crossing.  When it is time to remove the crossing, simply undo the anchor points and lift the bundle out by the cables that are attached the pipe on top.  After the bundle is removed be sure to inspect it for any damage and replace any damaged pipes before re-use. 

Once the bundle has been removed, always remember to stabilize your approaches, just as you would with any stream crossing.  Also, keep in mind where appropriate stream crossings should be located: straight sections of stream that can be approached at a 90-degree angle.  This concludes this month’s BMP Q&A, remember you can send any questions to me at tthomas@tfs.tamu.edu, or you can phone them in by calling (936) 639-8180. 

*This article was published in the May 2013 edition of the Texas Logger

What to consider: Culverts

Poorly installed and improperly designed culverts can lead to excessive erosion, damage to streams, high maintenance costs, and road failure.  In order to prevent these issues it is important to consider culvert type, diameter, length, and location.

Excessive sedimentation from a poorly planned culvert

Type
There are two types of culverts: stream crossings and cross drains.  The first type, a stream crossing culvert, is generally placed in a location where a permanent stream crossing may be necessary, since it is often too costly both economically and ecologically to remove. These culverts allow both stream flow and aquatic wildlife to pass underneath the road.  The second type, cross drains, are used to transport upland runoff, accumulated in road ditches on the upland side of the roadway to the lower end where both flow volume and velocity can be dissipated.

Mouth of a cross drain culvert

Diameter
Culvert diameter is determined by both the soil type on the site, how steep the site is, and the acreage of the watershed that the culvert drains.  Taking into consideration these factors ensures that the culvert is sizable enough to handle the maximum volume of water that it may encounter.

Culvert size chart from page 51 of the Texas Forestry Best Management Practices Handbook 

Length
Culvert length is dictated by how wide the road is.  Culverts should be long enough so that each end extends at least one foot beyond the edge of the fill on either side.

Location
Culvert location is paramount in dictating the longevity of the culvert.  In stream crossings, culverts should be placed in a section of stream where the channel is straight and the stream bed is firm.  Cross drain culverts should be spaced out depending on slope.  Cross drain culvert spacing can be determined using the following formula:

Culvert spacing = (400'/slope%)+100
         *Slope in percent is expressed as a whole number (i.e. 15%=15)
               
            Example: Spacing = (400'/15)+100'
                          Spacing= 127'

Conditions
In addition to factoring in culvert specifications, it is also extremely important to factor in current weather conditions and trends.  Culvert installation should be done when stream flows and chance of rain are low.  Ideally, the entire installation process should be completed before a rain event.

UP NEXT:  Installing your culvert

November 2012 BMP Q&A

By: Todd Thomas, Water Resources Forester, Texas A&M Forest Service

Q: Just the other day, the topic of temporary stream crossings came up.  More specifically, how does TFS recommend that we cross streams and how should they be left after operations are complete on the site? 

A:  Excellent question, if you don’t give proper care and thought to your temporary stream crossings, many of the BMPs you have put into place on the tract can be negated.  A key component of any forest management activity is access.  In some cases you may not have to cross streams to access parts of a tract that you need to.  For instance, there may be another entrance or road that has been overlooked, a neighboring landowner may grant access through their property, or it may not be necessary at all once you have stepped back and looked at the bigger picture. 

More often than not, you are going to have to put in a stream crossing or two to get the job done, but remember to keep them to a minimum.  When selecting a location be sure and look for a straight, narrow section of stream with relatively low banks.  This will minimize the amount of disturbance to the stream and stream banks.  Higher banks result in a greater amount of disturbance than lower banks, and straight, narrow sections limit the amount of exposure the streambed receives from equipment.  Once you have selected the appropriate location, be sure that your approaches to the stream as well as the crossing itself is at a 90 degree angle to the stream, this ensures that as equipment crosses, the amount of the stream exposed to equipment is greatly reduced. 

Log skidder dragging logs across a temporary bridgemat

If the banks of the stream are too high for equipment to cross directly, a common approach is to lay slash bundles into the stream bed that can be driven across.  The only downside to this is that they must be removed following operations; this can take some effort and can result in a serious amount of disturbance.  However, this is a much better option than dirt crossings.  Dirt crossings should never be used and are never recommended.  Remember, the point of BMPs is to keep extra dirt from entering the streams, not to add any more.  One of the easiest alternatives for these types of crossings is to use bridgemats, otherwise known as skidder mats or dragline mats.  These mats are constructed of hardwood cants that have been bolted together and are extremely durable and can be used over and over again.  They can be laid in place with the grapples of the skidder and removed in the same fashion once you are done.  The best part is that you have stayed out of the stream bed completely and maximized water quality protection at your temporary stream crossing. 

Once it is time to move off site, temporary stream crossings should be removed and the approaches should be stabilized to reduce erosion.  One way to stabilize approaches is by revegetating them.  On page 65 of the most recent BMP handbook there are guidelines for revegetating disturbed areas, there is even a chart that gives you different seeding options so that you can use the best seed for your site.  Another alternative is to distribute fine slash down the approach (being sure not to put any in the stream bed) and drive over it to ensure firm placement, followed by larger, more coarse slash. 

In conclusion, remember to keep stream crossings to a minimum, always stabilize your approaches and to never use dirt crossings.   Keep the questions coming so we can shed some light on any best management practice confusion that might be out there, you can send your questions to me at tthomas@tfs.tamu.edu or just phone it in by calling (936) 639-8180.

*This article was published in the November 2012 issue of the Texas Logger

New BMP Demonstration on the Jones State Forest

Texas Forest Service recently installed a new stream crossing demonstration on the W. Goodrich Jones State Forest in Conroe. The demonstration is part of the forestry Best Management Practices (BMPs) demo tour that provides an opportunity for the forestry sector to see how properly installed BMPs look and function. The tour currently has 10 demonstration sites.

The crossing utilizes 3 portable bridgemats (4' x 16' x 8') made out of sturdy hardwood cants fastened together with threaded rods. The bridgemat crossing provides reliable access across Mill Set Gully and replaces a failing timber bridge. Bridgemat crossings are a readily-available and proven method of crossing streams and ditches in a ‘low-impact’ manner that protects water quality. They are simple to install, and can be easily removed and transported to another location after an operation is completed.

To learn more about this and other BMP demonstrations stop by the Jones State Forest, or visit our virtual BMP tour.

BMP Fact Sheets

Need Some Quick Info on Forestry Best Management Practices?


Texas Forest Service has several fact sheets available to help you understand various aspects of using Best Managment Practices during your forest operations. These are a great resources for landowners or land managers unfamiliar with forestry BMPs.

Topics include:

• BMP Guidelines Overview
• Forest Roads
• Reasonable BMP Expectations
• BMPs for Reforestation and Site Preparation
• Stream Crossings
• Streamside Management Zones 

June BMP Q&A

By: Chuck Coup, BMP Forester (Ret.), Texas Forest Service

Q:   When dealing with temporary stream crossings, I have been told several things about where to put waterbars to prevent road sediment from entering the stream. I have heard that you are supposed to put a waterbar on each side of the streambank at the crossing to prevent any water flowing down the road from getting into the stream. I have also been told to never put any waterbars inside the SMZ. Would you please clear this up for me?

A:   It is certainly easy to see how both recommendations could seem valid, but let’s see if we can’t shed some light on this debate.

The thought behind closing out a temporary stream crossing by constructing a waterbar at the edge of a stream is that it will provide a place to stop or redirect any water entering the SMZ just before it gets into the stream. However, experience has shown that waterbars at the streamside typically serve more as a source of sediment. These waterbars will often slough off into the stream with a heavy rain. If rains are heavy enough to cause the stream to overflow its banks, the waterbar may be completely washed away.

Therefore, as a general rule, waterbars should be kept at least 50 feet away from the stream channel (i.e., outside the SMZ). A properly constructed waterbar at the edge of the SMZ will divert water off the road as it approaches the SMZ and give plenty of distance for the water to slow down, spread out, and drop any sediment before it reaches the stream. Just be sure you don’t construct a long narrow wing ditch off that water bar into the SMZ that will channelize the water and direct it into the stream.

Of course, as with any rule, there are exceptions. If your SMZ is wider than the minimum 50-foot recommendation then it would be alright to have a waterbar within the SMZ. If you are dealing with steep approaches and erosive soils then it may be necessary to construct an additional waterbar with in the 50-foot buffer. However, you should try to keep it as far back from the stream bank as possible and be sure that it does not discharge directly into the stream channel.

It is important that you also re-establish the original slope and condition of the streambank as best as you can when you pull out your temporary stream crossing. An effort should be made to stabilize the streambanks where the crossing and approaches to the crossing were. Stabilizing these areas becomes even more important for crossings with more erodible soils or steeper slopes. This can be accomplished using grass seed or logging slash; however, you want to make sure that any logging slash you put next to the stream is well incorporated into the soil and above flood level so that it will not wash into the channel during high flows. If this is done, there should be little or no erosion at the crossing.

As always, the very best way to prevent sediment from entering a stream at a crossing is to avoid putting in the crossing in the first place.

For more information on stream crossing BMPs visit the Texas Forest Service webpage at http://txforestservice.tamu.edu/water or contact me at (936) 639-8180.

* This article was published in the June 2011 issue of the Texas Logger

August BMP Q&A

By: Chris Duncan, BMP Forester (Ret.), Texas Forest Service

Q:   I have a tract of timber which was clearcut last fall.  The logger who harvested the tract did a bang up job on installing necessary BMPs where they were needed.  My consulting forester has recommended that I conduct a site preparation burn later this summer to prepare the site for planting.  The tract has a stream on it that usually runs for about 3 months in a typical year.  Are there any special BMPs in regards to prescribed burning that should be implemented to ensure the water quality of the stream is not adversely affected?

A:   Glad to hear that you were happy with the job your logger did in implementing BMPs where they were needed.  Prescribed burning can be a beneficial management tool when used properly with trained personnel. Site preparation burns are often the hottest type burn and can remove a substantial amount of the surface organic material. This type of burn would have the greatest potential for increased surface runoff or soil erosion, particularly on steeper slopes.  Use the following guidelines to help reduce the risks to water quality and soil erosion on your tract.

Site preparation burning creates the potential for soil movement.  A significant amount of soil movement can be caused by the preparation for the burns, i.e., firebreaks. Firebreaks should have water control structures that divert runoff away from water bodies in order to minimize erosion.  Site prep burns on steep slopes or highly erodible soils should only be conducted when they are absolutely necessary and should be as "cold" as possible.  Stabilize and revegetate firelines, if needed, on grades in excess of 5% or areas subject to accelerated erosion or known sensitive areas.

Firelines should be constructed on the perimeter of the burn area and along the boundary of the Streamside Management Zone (SMZ). The purpose of protecting the SMZ from fire is to safeguard the filtering effects of the litter and organic matter.  All efforts should be made to minimize the impact from site-prep burning within an SMZ.  Firelines should follow the guidelines established for logging trails and skid trails with respect to waterbars and wing ditches, and should be only as wide and as deep as needed to permit safe site preparation burns.  Firelines which may cross a drainage should be turned parallel to the stream or have a wing ditch or other structure allowing runoff in the line to be dispersed rather than channeled directly into the stream.

Finally, make plans to maintain your firelanes after the burn has been completed.  Firelanes on highly erodible sites or other problem areas should be inspected periodically to correct erosion problems by installing dips, wing ditches, waterbars, etc. and/or by seeding.  Mowing, rather than blading, should be used to maintain firelanes in order to avoid exposing mineral soil to potential erosion.

For more information on forest road BMPs and other BMPs visit the Texas Forest Service webpage at http://texasforestservice.tamu.edu/water, contact me at (903) 297-3910.

* This article was published in the August 2010 issue of the Texas Logger

March BMP Q&A

By: Shane Harrington, BMP Forester (Ret.), Texas Forest Service

Q: Last month I addressed the overall results of the most recent Texas Forest Service BMP Implementation Monitoring report that was released in December 2008.  This month I would like to address the areas in which deficiencies were seen.  Next month I will address the areas in which improvements were made.

A: In case you missed it the Texas Forest Service completed its seventh round of BMP Implementation Monitoring and released a report in December 2008 detailing the results of the monitoring.  The Texas Forest Service conducts these monitoring rounds approximately every two years in an effort to demonstrate how well BMPs are being implemented on silvicultural operations here in East Texas.  During the Round 7 monitoring two major deficiencies were noted: 1) failure to remove and stabilize stream crossings on temporary roads (temporary stream crossings) and 2) inadequate Streamside Management Zones (SMZ) widths along intermittent and perennial streams.

Temporary crossings should be removed and restored following use

To begin with, let’s take a look at the first deficiency – failure to remove and stabilize stream crossings on temporary roads.  Historically this deficiency has been commonplace, which is of great concern because stream crossings are an area which can negatively impact water quality if they are not implemented properly.  There was an overall implementation rate of 82% on stream crossings on temporary roads during Round 7; however, for removing and stabilizing these crossings there was an implementation rate of only 62%.  A good job is being done at minimizing the number of temporary crossings, properly locating them, and correctly installing them.  According to the BMP Bluebook, all materials used to construct a temporary crossing should be removed immediately once the crossing is no longer needed and the approaches should be restored and stabilized to prevent or at least reduce the chances of sediment washing into the stream.  Round 7 revealed an increase in the implementation rate for removing and stabilizing temporary crossings compared to Round 6.  During Round 6 there was a 31% implementation rate compared to 62% in Round 7.  However, even though an increase in implementation was noted there is still a need to improve in this area in the future.

The second deficiency that was identified during Round 7 was inadequate SMZ widths along intermittent and perennial streams.  The BMP Bluebook states that an SMZ should be left along all perennial and intermittent streams and should have a minimum width of 50 feet and retain a minimum of 50 square feet of basal area per acre evenly distributed.  During Round 7, SMZs had an overall implementation rate of 82% while SMZ width and thinning guidelines (there are eight criteria evaluated for SMZs) had an implementation rate of 66% and 80% respectively.  While most SMZs evaluated during Round 7 met the guidelines regarding thinning within an SMZ most of the SMZs evaluated did not meet the width requirement especially on intermittent streams.  Streamside management zones are extremely important in slowing down runoff and overland flow reducing the chances of sediment or other contaminants reaching the stream.  Also SMZs are important in preventing thermal changes in the stream and are beneficial in providing travel corridors and habitat for wildlife.  Additionally, provisions in Senate Bill 977 provide property tax incentives for leaving SMZs along streams.  Contact your local Texas Forest Service office for more information.

Improvements were also noted during Round 7 compared to previous rounds and next month I will address the areas in which increased implementation was seen.  To view the full report titled “Voluntary Implementation of Forestry Best Management Practices in East Texas, Round 7” visit the Texas Forest Service webpage at http://texasforestservice.tamu.edu/water.  For more information regarding this report or BMPs please contact me at (936) 639-8180.

* This article was published in the March 2009 issue of the Texas Logger

BMP Informer - August 2008

August Issue of the BMP Informer Now Available

• What Can I Do About Dry, Powdery Summer Roads?
• From the Editor...
• Improving My Land - Revegetating Forest Roads
• How Do I Know What Size Culvert I Should Use?
• Forestry and Water Quality in East Texas
• Culvert Installation

June BMP Q&A

By: Jake Donellan, BMP Forester (Ret.), Texas Forest Service

Q:  In your opinion, if loggers had to focus on one specific BMP or area of BMPs what would it be and why?

A:  In evaluating BMP implementation all over east Texas, I see a lot of logging operations. Each logging operation is very different and yet the same elements are present on the majority of the sites I see. If I could get loggers to focus on one thing specifically it would be stream crossings.

I know we have beat this drum for a long time now but it really is a critical area of any harvest operation. Stream crossings are critical areas because this is where loggers can potentially have the greatest impact to water quality if precautions are not taken. As most of you have learned, sedimentation is the biggest concern with forestry operations and 90% of the sediment load comes from our forest roads. It is fairly clear to see that where our roads actually come into contact and cross streams, we have a recipe for problems if attention is not paid to protecting water quality by using proper BMPs.

Removing temporary crossings seems like a very simple task to undertake, it always amazes me when I run into temporary crossings that are left in streams. Most “temporary” crossings that are left behind are typically brush type crossings. These types of crossings do allow some water to pass through which makes them extremely useful to use during the operation. The reason they need to be removed is because they still impede water to a degree and also they trap debris on the upstream side of the crossing. Eventually they become blocked with leaf litter and become in effect a dam. Once this happens, it is only a matter of time before a blow out occurs and an extremely large sediment load around the crossing is eroded away and into the stream channel. This process is sped up during periods of high flow for the stream like during a major rain event. For this reason, most of these types of problem areas are considered significant risks to water quality both in real terms and also on the BMP Implementation Evaluation form. This process holds true for other types of temporary crossings left behind such as pole crossings or log crossings. According to at least one logger I spoke to, it takes less time to remove a brush crossing than it does to install it, and for that reason alone, there should be no reason a temporary brush crossing should ever be left behind.

Temporary crossings that are left in place following an operation can pose a significant risk to water quality

Another BMP as equally important as removing a stream crossing is stabilizing stream crossings and approaches. A lot of good work can be undone by simply not stabilizing the approaches. Approaches have to be stabilized because of their proximity to the stream channel itself. This limited amount of area provides little room for error when it comes to implementing BMPs properly. You can stabilize the approaches by laying down slash, laying down hay, seeding grass, and when necessary installing water bars. Water bars should only be installed on approaches if it is absolutely necessary to prevent a washout occurring on the approach due to steep slopes or moderate slopes on sandy sites. Again, because of the nearness to the stream if water bars are used, they must be installed properly at a 30 to 45 degree angle, 1 to 2 feet in height, tied in properly on the uphill side and venting water off the approach but not directly into the stream itself. When approaches are not stabilized, what typically happens is water begins finding its way down the approach and into the stream and before long a head cut starts right at the stream bank eroding sediment directly into the stream. Rain intensity, slope, and soil type all play a roll into how rapidly the head cut advances back up the slope and ultimately how much sediment is eroded into the stream. Stabilizing with rock or geo-textiles may be considered or necessary on approaches to permanent crossings.

These two areas, removing temporary crossings and stabilizing crossings and approaches, have consistently been problem areas for loggers throughout the history of BMP implementation monitoring. As I have pointed out numerous times, we already have been successful in implementing BMPs but that is no reason to sit on our laurels. If we, the forestry community, focus on addressing these two issues, I think we will have succeeded beyond anyone’s wildest expectations.

For more information regarding BMPs consult the Texas Forestry Best Management Practices book (a.k.a. the “Bluebook”), contact your local Texas Forest Service office, or you can contact me.

* This article was published in the June 2008 issue of the Texas Logger

BMP Informer - February 2008

February Issue of the BMP Informer Now Available

• Reforestation and BMPs
• Environmental Quality Incentives Program (EQIP)
• Improving My Land - Stream Crossings
• Management Considerations for Wildlife
• New Stream Crossing Workshop A Success
• Websites of Interest

BMP Informer - December 2004

December Issue of the BMP Informer Now Available

• Remember BMPs When Planting
• Seedlings On-line!
• Improving My Land - Permanent Stream Crossings
• How Do I Know What Size Culvert I Should Use?
• BMP Implementation Monitoring Program
• Forestry Acronyms

March BMP Q&A

By: Shane Harrington, BMP Forester (Ret.), Texas Forest Service

Q:  I recently inherited a tract just outside of Palestine.  The property has only one access road and over the years it has gotten in pretty bad shape becoming impassible.  The road has deep gullies running through it and appears to be below grade.  The road also travels across a bottom with moderate slopes (5-10%) and crosses a perennial stream.  I want to have permanent access to the tract so what options do I have to achieve this.  I also wanted to know if you are ever able to go out and give “on the ground” advice and suggestions concerning BMPs?

A:  First of all yes, loggers often call us and ask us to come out and give “on the ground” advice or suggestions regarding BMPs. 

Now lets get to your question about your access road.  It sounds like your road has gotten in pretty bad shape over the years.  I would like to start by saying that it is important that you consider using water control devices during any reconstruction of your road.  This is important because these devices will divert water off the roadway and help protect the site from excessive erosion.  Because the road will see a moderate amount of traffic during the reconstruction process and afterwards rolling dips should be used to divert the water and prevent excessive erosion.  Specifications for properly installing rolling dips can be found on pages 45 and 46 of the Bluebook.

A below grade road will constantly cause you problems.  In my opinion, the best thing to do is to have a dozer cut down the surrounding land and use this dirt to build up your road.  This will also help provide a natural outlet for diverted water.  Additional dirt may have to be brought in to finish building up the road to the desired height.  A mixture of dirt and rip rap may be used to build up the approaches.  This will make the approaches more stable and minimize any erosion on the approaches.  Crowning and seeding the road will also help stabilize it reducing the potential erosion hazard.  For proper seeding choices and rates see pages 64 and 65 of the Bluebook.

Lastly lets talk about what type of stream crossing you should install.  Since you want permanent access to the tract this means that you will have to install a permanent crossing. I would suggest installing a culvert if it will be able to handle the expected water flow.  To determine what size culvert to use refer to the Culvert Size Chart on page 50 of the Bluebook.  You want to make sure that you install the right size culvert because putting one in that is too small will eventually blow out.  A blown out culvert will cause more road problems, increased repair expenses, but more importantly it will impact the water quality of the stream through the high amount of sedimentation caused by the blown out culvert.  The Stream Crossings section on page 47 of the Bluebook also contains specifications on how to properly install a culvert.  If a culvert will not provide an adequate crossing then you may have to think about installing a bridge.  For this I would suggest that you get technical advice from someone specially trained in this area or contact your local NRCS office

Proper road construction and maintenance can be time consuming and expensive but are necessary if you want good access to your property.

If you need a copy of the Bluebook you can get a copy from your local Texas Forest Service office or you can view online at http://txforestservice.tamu.edu/water. If you have any questions or comments about BMPs please call me at (936) 639-8180. 

* This article was published in the March 2004 issue of the Texas Logger                                                                                                                                                                                                                                                      

BMP Informer - October 2003

October Issue of the BMP Informer Now Available

• Remember BMPs When Planting
• Seedlings On-line!
• Improving My Land - Permanent Stream Crossings
• How Do I Know What Size Culvert I Should Use?
• Forestry and Water Quality Protection in East Texas
• Culvert Installation

BMP Informer - October 2002

October Issue of the BMP Informer Now Available

• Remember BMPs When Planting
• Seedlings On-line!
• Improving My Land Permanent Stream Crossings
• How Do I Know What Size Culvert I Should Use?
• Forestry and Water Quality Protection in East Texas
• Culvert Installation

August BMP Q&A

By: Hughes Simpson, BMP Forester, Texas Forest Service

Q:   A major perennial stream flows through our property and floods at least once a year. These high waters have blown out several culverts and caused severe erosion on the stream banks. Reinstalling another culvert is extremely expensive, so we have decided to retire this rarely used crossing. However, we still would like to stabilize the banks to keep them from washing into the stream. Is there an effective way to accomplish this?

A:   Stream crossings can be very expensive to install and maintain, and if they don’t function properly, can cause major impacts to water quality. These “contact points” are areas where soil can directly enter streams. Retiring old crossings that are not used and stabilizing their stream banks are excellent practices to reduce the potential severity of sedimentation problems.

Restored and seeded stream crossing

There are several effective ways that you can stabilize the stream banks of this crossing. Establishing a good vegetative cover on these erodible sites through seeding will help keep the bank intact and filter runoff water before it reaches the stream. Seed mixes should include a variety of grasses suited for the site conditions present to ensure a high survival rate. Planting in the spring or fall can greatly increase the success of this operation. Fertilizers should not be applied inside the Streamside Management Zone (SMZ) to prevent stream contamination.

Depending on the time of year and the site conditions, grasses may not always grow in these areas. Spreading hay along these banks can also provide erosion control. This method is extremely effective when it is done after seeding. As the hay decomposes, the grass seed begins to germinate and holds the soil in place. This material can be applied more efficiently and evenly distributed using hay blowers. Care should be taken to avoid hay from reaching the stream channel.

Another method that works well is installing rock along the slopes. Securing this material in place can provide great erosion protection and bank stability, however this procedure is generally more expensive than the above mentioned. It is also important to prevent rocks from entering the channel and impeding stream flow.

There are many other techniques that can be implemented to help with this problem, including geotextiles, bioengineering products, and other erosion control fabrics. More information can be found on the Texas Forest Service webpage under the BMP Product and Vendor Guide. If you have a question regarding BMPs, please call me at (936) 639-8180.

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

April BMP Q&A

By: Hughes Simpson, BMP Forester, Texas Forest Service

Q:   I have installed several culverts that have blown out this winter due to high rain events. Last month you mentioned a workshop for county commissioners and road crews that talked about proper culvert sizing and installation? I would like to know how I can prevent my culverts from blowing out, but question whether they should be installed to withstand a 5 inch rain. Is this reasonable? What can I do?

A:   Sorry to hear about your culverts blowing out. Culverts can be used as effective stream crossings, but when they fail, they can be very costly to replace, not mentioning the time it takes to reinstall them, but also the extra sediment that reaches the stream channel. This is why it is so important that proper culvert sizing and installation techniques are used.

It may seem as if a 5 inch rain is not a common occurrence in East Texas and would be hard to plan for, but in all actuality this is not as rare as you might think. This type of rain event does occur, especially in the last couple of years. Installing best management practices (culverts, waterbars, wing ditches, etc.) to safeguard against larger storm events would not be economically feasible and even the best structures would fail during natural disasters.

Before installing culverts, it is important to know the soil type, slope, and how big your drainage area is so you can properly size your culvert. Soils information can easily be found using a soil survey. Topographic maps can help you determine the slope and drainage area of the tract that you are working. To calculate the drainage area, use a topographic map to locate hill tops and decide which way runoff water will drain through a particular point (stream crossing). On a standard 1: 24000 USGS topographic map, one square inch equals 90 acres.

Once you have determined the soil type, slope, and drainage area, you can use a culvert sizing chart to assist you with selecting the right culvert. This chart is found on page 50 of the Texas Forestry Best Management Practices Handbook. Make sure that you buy a long enough pipe so that at least 1 foot extends on each side past the fill material.

Place the culvert in a firm, straight section of the stream channel on a 1-2% downgrade to prevent clogging. There should always be at least one foot of cover to help anchor culverts in and protect them from being damaged by traffic. A general rule of thumb to follow is one foot of fill per one foot of culvert diameter. It may also be necessary to install rip rap, geo-textile cloth, or large stone at the inlet and outlet to reduce erosion and washouts. The approaches to the crossing should be straight and at right angles to the streambed.

Frequent inspections and proper maintenance needs to be performed on all culvert crossings to ensure that they are safe and functional. A clogged or damaged culvert is very susceptible to blowing out under normal rainfall. If you have a question regarding BMPs, please call me at (936) 639-8180.

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

June BMP Q&A

By: Hughes Simpson, BMP Forester, Texas Forest Service 

Q:   I am harvesting a tract of timber in Sabine County near Milam, in which a major stream bisects the property.  The landowner wants to gain permanent access throughout the entire tract.  This perennial stream carries a lot of water, has very steep banks, and is about 30 feet wide.  Do you think it would be possible to accomplish this without impacting water quality?  If so, how would you recommend crossing it?               

A:   Yes, it is certainly possible to cross this stream and minimize the impacts to water quality.  However, given the stream conditions, the task of doing this can become quite expensive.

The best and most economical way to achieve this is to not cross this stream at all.  Spending several hundred dollars buying an easement from an adjacent landowner will usually be cheaper than building a bridge or putting in a culvert.  This method also provides the greatest protection to water quality.

Many times, gaining backside access is not possible and the stream must be crossed directly.  Careful consideration must be given to a stream of this size.  It is imperative that all stream crossings be installed at right angles and in straight sections to the stream channel.  This reduces the potential impact to water quality. 

Tank cars can be installed securely in the streambed and will function as large culverts, which may last between 30 and 50 years.  The walls of these cars usually range anywhere from ½” - 1” thick, depending on the weight they must be able to withstand.  Federal law mandates that tank cars go through steam cleaning before being used as a stream crossing, to prevent any impacts to water quality.

Flat cars and box car beds are also another method that is commonly used to cross streams of this nature.  These tools function more as bridges that are appropriate for spanning larger streams.  The major factor in determining what product to use is the actual width of the steam (distance that must be crossed).  Flat cars are generally 89 feet long and about 8-9 feet wide.  Box car beds are 50-60 feet long and 10 feet wide.  When installing either one of these “bridges” it is important to anchor them into the bank with at least 8 or 10 feet of overhang on both sides of the stream.

Flat cars can be used to establish sturdy bridge crossings

Timber Creosote bridges are also used to gain permanent access across large streams.  They can handle heavy traffic, minimize the amount of sedimentation and erosion, and also function under high water conditions.  The major drawback to these devices is the high cost.  When installing these bridges, choose approaches that have a constant grade.  Build abutments parallel to the stream and imbed them into good foundation material. 

Timber Creosote bridges are a common approach to establishing permanent stream crossings

To find out more information about suppliers and prices of these products, please consult the TFS Product and Vendor Guide.  The Texas Forest Service does not endorse the use of specific products or vendors listed in this guide.  You can view this on the Internet at http://txforestservice.tamu.edu/water.  If you have a question regarding BMPs, please call me at (936) 639-8180.

* This article was published in the June 2001 issue of the Texas Logger

February BMP Q&A

By: Jake Donellan, BMP Forester (Ret.), Texas Forest Service

Q:   Due to the fact there were no questions this month, I would like to look in detail at some of the deficiencies noted in the latest round (Round 4) of BMP compliance monitoring.

A:   The report, “Voluntary Compliance with Forestry Best Management Practices in East Texas,” noted two major deficiencies during the evaluation of 150 forestry sites from June 3, 1998 to August 31, 1999. The first area of deficiency was sedimentation from stream crossings. The second area of concern was erosion problems from skid trails and temporary roads. This month lets look at the problem with stream crossings in closer detail.

Stream crossings can potentially contribute a large portion of sediment to a stream, thereby impacting water quality. This is one reason why we should really work hard to install them properly. The best stream crossing is one that never occurred. How can this happen? During the planning stage of your harvest operation, use tools like aerial photographs, topographical maps, and soil surveys in combination with field reconnaissance to determine site conditions.

By using these tools and getting out on the ground, you may be able to spot some backside access to the timber. Sometimes it is worth paying an adjoining landowner a couple hundred dollars to gain access than it is to build a crossing. If that is not possible, and many times it isn’t, then it becomes really important that you install your crossing properly so that you minimize the potential for sedimentation to occur.

There are a number of methods available to successfully cross streams and have little impact on water quality. You could try using a brush crossing or laying logs in the stream channel lengthwise. These types of crossings are very inexpensive and generally have a minimal impact on water quality as long as the material is removed promptly. Another alternative is temporary bridges like crossing mats or a bridge made of poles that can be loaded onto the truck later. When using culverts for permanent or temporary crossings, it is extremely important that they be properly sized. The culvert should be large enough to handle the stream’s maximum flow. They should also be maintained and kept free of debris. There is a culvert size chart located on page 50 in the Texas Forestry Best Management Practices – “Bluebook.”

Lastly, you should always cross streams at right angles and use of equipment in the streambed should be kept to an absolute minimum. It is also important that the approaches to the crossing be stabilized with appropriate structures. Stream crossings also require frequent inspections during operations to determine their functional and safe condition. When needed, corrective measures should be taken immediately to fully restore the crossing.

Next month if there are no questions we will look at how to improve on erosion problems from skid trails and temporary roads. If you do have a question regarding BMPs please contact me.

* This article was published in the February 2001 issue of the Texas Logger