Protecting the watershed Part 1: compost use in riparian buffers

Photo of river winding through farmland

Restoration of riparian buffers is essential to watershed protection.

Riparian zones are stream or river banks.  In nature, they are vegetated areas populated by water-loving trees, shrubs, flowers, and grasses.

Healthy riparian areas help prevent erosion.  Plant root systems hold the soil.  Vegetated strips stop pollutants from reaching the stream.  Riparian zones provide food and habitat for aquatic life.  They help moderate water temperatures with their shade.

Some age-old practices are now recognized as recipes for watershed disaster.

These include:

  • Straightening streams and rivers
  • Removing vegetation
  • Farming up to the bank
  • Giving livestock access to banks and waterways

But over half of the wetland and riparian zones in the contiguous 48 states have been destroyed.  Almost all of this damage is attributed to human activity.  As a result, repair work needs to be done if these buffers are to do the job nature intended.

Thankfully, responsible farmers and developers are no longer as cavalier about riparian zone destruction.

What can you do to protect and repair riparian zones?

Rehabilitate stream buffers. Consider widths ranging from 25 to 100 feet on each side of the waterway, depending on topography and land use.

Within these zones —

DO vegetate with a variety of trees, shrubs and other plants.  Native species are always good choices.  But select for hardiness and appropriateness to the locale.  Also, be mindful of riparian zones when planning land disturbance activities.  Contact a water-focused agency for information about permits and funding support for riparian buffer protection and restoration. Examples include the Natural Resources Conservation Service and  U.S. Fish and Wildlife Service. 

DO NOT remove plants, straighten sections of the waterway, or allow livestock or heavy equipment in the zone.  This includes farming equipment.

What can compost do in riparian zones?

Compost holds water.  More specifically, organic matter holds water.  And a typical compost is about 50 percent organic matter.  Adding compost to the soil boosts its capacity to hold water.

The EPA says every percent rise in soil organic matter results in 16,000 more gallons stored per acre foot.  With good organic matter content, water retention during the typical rain event (1 inch or less) can approach 100 percent.

Compost Best Management Practices (BMPs) are also effective.  Use compost socks, berms, and blankets as erosion control measures in areas of high soil disturbance.

Manage stormwater at the source

Imagine stormwater-sensitive neighborhoods and commercial districts.  Every lawn and parking lot will sport a strip of lush vegetation between —

  • the property and the sidewalk
  • the gutter downspout and street
  • the lawn and a drainage ditch or stream.

Calculate the cost:benefit ratio of soil amendment versus massive stormwater diversion/collection infrastructure projects.  Amendment costs pennies per gallon stored, not dollars.

Of amendment or infrastructure, which has the potential to offer the highest level of watershed protection? Which stops stormwater at the source? Which offers the more economical solution?

The best way to avoid the ravages and expense of stormwater runoff is to prevent runoff at the source.  Consequently, compost use cannot be excluded from any effective stormwater control program.  This includes the restoration of riparian buffers.

One product, many benefits

Amending soil with compost —

  • Reduces the amount of chemical fertilizers required.  Compost does provide nutrients, but it offers so much more.  Soil high in organic matter is not as prone to leaching.  It holds more nutrients at the root zone, including those from synthetic sources.  In addition, the microbial activity delivered through compost use improves nutrient uptake.  Reduced chemical use equals reduced pollutant runoff.
  • Relieves compaction.  A loose, friable soil will encourage percolation, not runoff.  Healthy soil also encourages root developmen.  This helps hold soil in place during rain events.  Reduced runoff volume equals reduced sedimentation and water pollution.
  • Saves water.  If the soil is holding moisture, crops and landscapes don’t need to be watered as often.   Better water retention equals reduced irrigation requirements and irrigation runoff.

Read more

Innovative Uses of Compost:  Reforestation, Wetlands Restoration, and Habitat Revitalization

This post was inspired by an article about the River Stars Home program of the Elizabeth River Project.  It is an advocacy group working to restore the Elizabeth and Lafayette Rivers in Norfolk, Va.  Read the article here:  Who can help stop river killers?