Managed Grazing Can Improve Stream Corridors

Removal of livestock grazing from stream corridors is commonly recommended but not necessarily a good option for management of the stream corridor. When grazing is terminated, the stream is subjected to changes because of the shift in the composition of the plant community.

• At first, the grasses become much more healthy and vigorous because of the lack of grazing, especially where the grazing management was “continuous grazing” prior to abandonment of grazing.

• Over time, the plant community will shift to tall, broadleaf herbaceous plants. Early successional woody species (boxelder and willow) will become established. Under a grazing regime these would be eaten by the livestock, or the plants would not have been able to withstand the livestock traffic and compaction.

• As the woody species become more numerous, increase in size, and provide a major portion of the canopy that shades the ground, the grasses diminish and eventually disappear. This leaves the woody species and some shade tolerant, broadleaf herbaceous plants on the streambanks and in the riparian corridor.

• As grasses are eliminated, the stream channel itself changes. The grasses that occupied sloping streambanks had an extensive and fine root system that could, in most cases, effectively prevent erosion. The herbaceous broadleaf plants and woody species that replace the grasses do not have root systems that are effective for protecting the streambanks. Erosion of the banks occurs; the banks become vertical and unprotected by vegetative cover and the stream channel becomes wider and shallower. The stream channel also is impacted by sediments so the value for fisheries is significantly reduced.

We Can Use Livestock to Improve Streams

Streams that have been damaged from overgrazing can be rejuvenated using a managed rotational grazing system for the entire pasture, and by controlling grazing on streamside paddocks. Even vertical stream banks can be “gentled down” by livestock hoof action. Initially, you’ll use high stock densities on small sections of the stream. At first, stream paddocks may need fairly long rest periods to allow for establishment of new plants and recovery of existing vegetation after the grazing event. As the stream shows improvement, rotational grazing may be done on a more regular basis. Monitoring the streamside paddocks is very important so that proper grazing decisions can be made.

Here’s How

When you’re developing a rotational grazing plan that includes a stream, you’ll need:

• well thought out objectives related to what the stream will look like when the plan is fully implemented;

• management strategies for the forages;

• a system of fencing;

• stream crossings;

• a system of providing water for the livestock;

• provisions for easy movement of livestock; and

• access requirements for machinery.

You also need to keep in mind stream characteristics that affect your plan like stream size, the soils on the stream bank, flooding potential and the depth of the stream channel, and water quality.  I talk more about that in the booklet.  For now let’s concentrate on three options for paddock design and layout to manage livestock impact on streams corridors.  Each option is based on stream characteristics and on the characteristics of the adjacent pasture.  Within each of these options there can be some variation based on your site’s specific characteristics.

Fence to include the stream in adjacent paddocks.

With this option the stream is included in the paddocks that it flows through. Livestock have full access to the stream while they’re in a paddock. The stream serves as a source of drinking water. Constructed access points are a good option in this system as a way of reducing livestock impact on stream banks.  Because the fences will cross the stream, this type of layout should be considered for small streams, where flooding rarely occurs, or where flood waters are at slow velocities and do not disrupt the integrity of the fences.

An option for this layout is to fence so that the stream is included on only one end of the paddock.  Livestock are unlikely to cross the stream for a small sliver of pasture on the opposite bank, allowing vegetation to grow with little grazing pressure.  This reduces impact to areas that need additional rest or time to recover from livestock impact.

Monitor the stream bank to track where livestock impact should be increased or decreased to benefi t the stream and the plant community. Install temporary fences or gates to make it easy to move livestock to areas that need increased impact, or to keep them away from areas that need additional rest.

Fence to make the stream corridor a separate paddock.

This is a very good option when the stream is a larger than those discussed above and in cases where flooding frequency, duration, and intensity would make fence maintenance difficult. Only two permanent fences that cross the stream are necessary: one at the upstream end of the corridor and one at the downstream end of the corridor. This reduces the maintenance workload for fences.

This is also a good option when the stream corridor needs to be managed closely to obtain the desired eff ect. Examples of this are streams with important fisheries, significant streamside wetlands or streambanks with soils that are easily damaged by grazing. You can split these stream corridors into several smaller paddocks to apply appropriate pressure.  Temporary fences made from polytape or polywire and using step-in posts are commonly used in these situations so they can be rolled up when not in use.

Stream crossings are necessary where the substrate in the stream bottom is not solid enough to support livestock traffic or where the stream is incised deeply into the landscape and the livestock have difficulty traversing the stream. Crossings may also serve as access points for livestock watering. We’ll talk about how to water livestock when they’re not in stream side paddocks in the next article in this series.

Fence to exclude the stream corridor

In some cases it is in the best interest of the stream to totally exclude livestock. This is pertinent in the following situations:

• The stream is so deeply incised into the landscape that livestock grazing on the stream banks or watering from the stream cause serious trailing and erosion issues.

• The soils of the streambanks are sand and gravel, and any livestock traffic will damage the soils and vegetation. In these soil conditions the vegetation easily suffers serious damage and cannot recover adequately enough or quickly enough to stabilize the stream banks to protect them from erosion.

• In the case of pastures adjacent to very large streams or rivers, it is sometimes best to exclude the livestock. Th is is especially true if the stream floods often or if the banks of the stream are seriously eroding. High vertical banks along major streams are difficult to positively impact with livestock grazing.

Don’t Do This!

Don’t install travel lanes close to and parallel to streams.  Travel lanes damage vegetation, create bare soil, and have lots of manure and urine.  All these things increase erosion and reduce water quality.

Don’t set up your paddocks so that livestock have to travel long distances to water.  This causes trailing and heavier use of forage closest to water.  Cattle will generally graze uniformly up to a distance of 800 feet from water. Beyond that distance forage utilization diminishes and “zone grazing” is evident. To overcome this, size paddocks to match the production of the forages, the desired grazing period, and the projected forage requirement of the herd.

Paddocks should be planned and installed to use the stream for water to the extent possible, with the above distance criteria in mind. Paddocks that do not have access to the stream should be set up with a functional livestock watering system.  I’ll talk more about watering systems in the next article.