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October 30, 2002 "Riparian Buffers: Impacts on Phosphorus and Sediment
Control"
October 30, 2002 Roundtable Minutes
Conclusions & Resolutions
- Buffers are complex and not a water quality panacea.
- Sediment and nutrient management needs to be a series of controls
-Must consider up-slope control practices as well.
- For sediment control, length of buffer may not be the most important
-Other factors: grass characteristics, buffer maintenance, effective
ponding behind buffer, etc.
- For control of nutrients, length and infiltration capacity of the
buffer is important.
- Buffer characteristics must be matched to landscape conditions, farming
systems, needs of the water body being protected.
- Need to examine source-control practices (i.e. agricultural management
practices) as well as remedial practices to control sediment and phosphorus
losses.
Issues to Resolve
- Need "systems" buffer research - not "single component"
research.
-Systems research needs to be conducted at various spatial and temporal
scales.
- Buffer design difficulties and the inconsistent literature base.
- Purpose of buffers.
-Sediment control,
-Nutrient control (N, P, both),
-Aesthetics,
-Pesticide control,
-Chemical control,
-Pathogen control,
-Etc.
- Loss of productive agricultural land with the wide-spread installation
of buffers.
-Particular concern in Wisconsin's western, driftless area
- Will any general/universal design criteria for buffers ever be developed?
- Need limnologist input on the whole buffer issue.
- Must maintain realistic expectations of the conclusions that can
be drawn from the buffer research agenda.
Research & Information Needs
Note: The following list is not prioritized!
- Examine the change in buffer effectiveness over time.
- Identification of areas where buffers are not effective.
- Explore the impact of climate (particularly northern climate) on buffer
effectiveness and durability.
-Snowmelt release of P
-Vegetation release of P
- Define the maintenance requirements for buffers
-These will vary seasonally
- Identify upland management practices that will allow for maximum buffer
effectiveness.
- Examine the economic impact of buffers.
-Explore positives and negatives.
-Are there vegetative species that can be used in buffers that will
have an agricultural benefit?
- Identify landowner constraints to the installation of buffers.
- Investigate and define site-specific influences on buffer design characteristics.
-Slope, soil type, cropland practices, etc.
- Determine the appropriate vegetation species for maximum buffer effectiveness.
-Balance with agricultural benefit.
- Explore alternative buffer designs.
-Vertical characteristics rather than horizontal characteristics
-Grass height and "dimples", berms within buffers, etc.
- Develop methods for controlling or managing the impact of large episodic
events (storms) on buffer "failure".
- Evaluate the effectiveness of a single, contiguous buffer verses a
series of buffers.
- Determine the secondary benefits of buffers.
-Wildlife, fish, aesthetics
-Impact of these other benefits on buffer design
- Develop methods for determining buffer effectiveness (or ineffectiveness).
- Develop a ranking tool for buffer position on the landscape.
-Maximize effectiveness, minimize cost
- Conduct in-field studies utilizing natural rainfall in addition to
simulated rainfall studies.
- Evaluate natural buffers (grass, trees, brush) versus grass buffers.
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