MD.450.9.1, TCH - Review of Draft Conservation Practice Standards

Maryland Bulletin: 450-9-1
Subject: TCH - Review of Draft Conservation Practice Standards
Date: November 19, 2008

Action Required By: December 19, 2008

Purpose. To request comments on four draft conservation practice standards.

Expiration Date. September 30, 2009.

Explanation. 

We periodically review and revise our Maryland conservation practice standards to maintain consistency with updated national standards. The following drafts are updates of existing Maryland standards:

• Access Control (Code 472) – Formerly called "Use Exclusion". Except for the new name, there are no major changes from the previous version.
• Filter Strip (Code 393) – This standard has changed significantly. The national criteria now require that there be a contributing watershed with at least a 1% slope. The filter strip must be designed to have a 10-year life span, following the procedure in the NRCS Agronomy Technical Note No. 2, Using RUSLE2 for the Design and Predicted Effectiveness of Vegetative Filter Strips (VFS) for Sediment. (See http://policy.nrcs.usda.gov/18578.wba to download this Tech Note.)
  
  The filter strip design is based on sediment delivery in RUSLE2 to the upper edge of the strip, and the ratio of the filter strip flow length of the flow path from the contributing area. Minimum design width for trapping suspended solids (e.g., sediment, organic particulates) is 20 feet with a minimum of 35 feet if dissolved contaminants (e.g., nutrients, pesticides) are identified as resource concerns. Species selected for establishment need to have stiff stems and a high stem density near the ground surface. Seed mixes and planting rates from Critical Area Planting (Code 342) will be used in most cases.

The following draft is a new Maryland standard that may be used instead of Filter Strip to establish grass buffers:

• Riparian Herbaceous Cover (Code 390) – This standard is applicable where herbaceous buffers are needed for water quality and/or wildlife habitat purposes, but will not be designed and managed in dense vegetation as "heavy-duty" filter strips. (Code 390 was previously used in Maryland several years ago for herbaceous buffers that were enrolled in CRP/CREP, MACS and WHIP.) The minimum width for trapping suspended solids is 20 feet, with a minimum of 35 feet if dissolved contaminants are identified as resource concerns. The minimum width for wildlife habitat is also 35 feet. For most sites and intended uses of these herbaceous buffers, seed mixes and planting rates from Conservation Cover (Code 327) will be used. Buffers that will be periodically cut for hay can be planted to a pure stand of grass-legume mix as listed in Pasture and Hay Planting (Code 512).

An electronic copy of each standard will be available for downloading from the eFOTG through my.NRCS or http://www.nrcs.usda.gov/technical/efotg/.  Select Maryland and select a county. The draft standards will be displayed in the main window under "What's Recently Changed" and "Draft eFOTG."

Contact. If you are unable to access the internet, you may request a paper copy or electronic copy of the documents from Anne Lynn at 443-482-2908.

Please return your comments on the draft standards by December 19, 2008 to the following individuals:

You may respond by e-mail or by regular mail. To the extent possible, we ask that you consolidate all comments from your office. If you have any questions, please contact the appropriate technical specialist, as noted above.

ANNE M. LYNN
State Resource Conservationist

< Back to 2008 Bulletins