Erosion and Sediment Pollution Control Program Manual.pdf

Site conditions such as soil limitations, wetness, steepness of slope, sun vs. shade, proximity to natural
plant communities, proximity to nuisance, noxious and/or invasive species, site history, previous
herbicide applications, and proposed land use should be considered in selecting seed mixtures.
Tables contained on the website maintained by the NRCS provide valuable information regarding soil
use limitations. Soils designated as “infertile,” “wet,” “droughty,” “acid,” etc. should be given special
attention when selecting seed mixtures. Table 11.3 identifies plant species which are tolerant or
intolerant of these soil conditions.
Wherever seeding is to be done on steep slopes (> 3H:1V), seed mixtures should be selected that are
appropriate for steep slopes. Table 11.5 in this manual and Table A (Section 804.2(b)) in PennDOT’s
publication 408 identify seed mixtures suitable for steep slope conditions. These tables also provide
information regarding seed selection for various proposed land uses (e.g. mowed vs. unmowed, high
traffic, etc.).
Fill slopes should be seeded and mulched at regular vertical increments — 15 to 25 feet maximum —
as the fill is being constructed. This will allow the bottom of the fill to progress toward stabilization while
work continues on the upper portion, making final stabilization easier to achieve and providing some
vegetative buffering at the bottom of the slope.
Wherever seed and mulch is applied by hydroseeding methods, the seed and mulch should be applied
in separate applications with the seed being applied first and the mulch sprayed on top of the seed.
This is to ensure that the seed makes contact with the underlying soil. Soil preparation should be
completed prior to adding seed to the hydroseeding equipment. Running seed through the pumping
system can result in excessive abrasion of the seed and reduce the percentage of pure live seed in the
application. Therefore all site preparation should be completed prior to the arrival of the hydroseeder.
In critical areas (e.g. adjacent to or within 50 feet of streams, ponds, or wetlands) a protective blanket
should be provided for all seeded areas. Consideration should be given to use of mulch with netting or
protective blankets for all seeded areas on slopes 3H:1V or steeper.
When wetland areas are temporarily disturbed, isolate and stockpile topsoil for replacement after
grading is completed. In most cases, no seeding of the disturbed area is necessary after the topsoil is
replaced. The soil contains sufficient seed and root material to reestablish vegetation. If temporary
vegetative stabilization is necessary, apply annual ryegrass at the rate not exceeding 48 lb PLS/acre.
Apply clean straw as a mulch at the rate of 3T /acre. No soil amendments should be used on wetland
areas.
Show all seeding, mulching, and soil amendment specifications on a detail sheet. References to a
standard seed mixture are not acceptable. The exception to this is for PennDOT, Pennsylvania
Turnpike Commission, or Bureau of Abandoned Mine Reclamation or other agency projects using a
standard seed mixture which is contained in the bid package. A copy of the seed mixture used in the
bid package should be made available to the reviewing agency upon request.
The beginning and ending of the germination season for each of the proposed seed mixtures should be
provided as well as directions for temporary stabilization of disturbed areas that achieve finished grade
during non-germinating seasons.
Vehicular traffic should be restricted from areas to be seeded to prevent soil compaction.
363-2134-008 / March 31, 2012 / Page 265