HomeMy WebLinkAboutWPO201900039 Plan - Other (not approved) Mitigation Plan 2019-06-21 Stream Buffer Disturbance Mitigation Plan
Type of Project: Site Plan—Hillcrest Vineyard Winery Tasting&Venue WPO 2019-00039
Status: New Project-See Section 10-71.c and Section 10-74.d.1.
Existing Buffer Condition: Forest
Preferred Mitigation: Preserve full buffer(100 feet); provide upslope stormwater controls to
prevent erosive flows through buffer; provide signage to mark buffer; provide optic orange
fencing during construction.
Other Mitigation Options: Encroachments for new development should be strongly discouraged,
and can only be allowed in accordance with Section 10-74(d). Encroachments should be the
minimum necessary and mitigation should include advanced stormwater controls upslope of
remaining buffer plus signage.
Existing Buffer Condition:Open Lawn, Meadow
Preferred Mitigation: Restore& preserve full buffer; provide upslope stormwater controls to
prevent concentrated flows through buffer; provide signage to mark buffer; provide optic orange
fencing during construction.
Other Mitigation Options:See above. Mitigation should include compensatory plantings,signage,
and advanced stormwater controls to prevent erosive flows through buffer.
Existing Buffer Condition:Scrub
Preferred Mitigation: Enhance& preserve buffer with plantings based on site conditions; provide
upslope stormwater controls to prevent concentrated flows through buffer; provide signage to
mark buffer; provide optic orange fencing during construction.
Other Mitigation Options:See above. Mitigation should include compensatory plantings
(depending on site conditions) and/or upslope advanced stormwater controls, plus signage.
Plantings: Remove existing invasive species: Eradicate invasive species including but not limited to
the following species listed and never introduce them while planting. For a complete list refer to
Virginia Department of Conservation and Recreation Invasive Plant Species List(Appended).
Retain existing native species including but not limited to the following. For a complete list, refer
to Virginia Department of Conservation and Recreation Native Plants for Conservation,
Restoration& Landscaping (Appended)
Installing Trees and Shrubs
Preparing the Site. Adequate site preparation and proper planting of seedlings and seeds is required for
successful establishment of trees and shrubs. Prepare the site for optimal tree growth by removing
weeds and past vegetation with burn-down herbicides and/or tilling just prior to the tree or shrub
planting. If the site is a grass pasture or an alfalfa field,the vegetation should be killed in the fall prior to
spring planting. If desirable native grasses are present,they can be maintained between the tree rows.
Planting Seeds.Tree seeds can be planted by hand or machine.When hand seeding, place the seeds no
deeper than two to three times the diameter of the seed. For example, a one-inch diameter black
walnut seed should be planted two to three inches deep. Broadcast seeds by hand or machine evenly
over the planting area and cover the seeds with soil using a disk or other implement. After seeds are
covered,the soil should be packed to ensure good seed to soil contact.
Specialized tree-seeding machines can plant either individual species or a mixture of species for a more
random distribution.When machine seeding, plant in a shallow furrow or spread seeds out and disk
them into the soil
Planting Seedlings.Tree seedlings should be planted in April or May. Seedling spacing, both in row and
between rows,varies with the expected mature size of the trees or shrubs being planted. NRCS
recommended planting densities are shown in Table I(refer to NRCS Conservation Practice
Standard Riparian Forest Buffer Code 391 for more detailed information). Seedlings come in several
forms which require different planting techniques (Figure 1).
Table I. NRCS recommended initial tree and shrub planting densities.'
Approximate Plant-to-plant Row-to-row Minimum Maximum
20-year Height Spacings Spacings Plants per Plants per
(feet) (feet) (feet) Acre Acre
Small shrubs less than 10 3-6 3-6 1210 4840
Large shrubs and small 10-20 6-10 6-10 440 1210
trees
Large trees greater than 20 10-15 10-15 200 440
'Adapted from NRCS Conservation Practice Standard Riparian Forest Buffer Code 391. Initial planting
densities are much greater than mature tree densities.
With bareroot seedlings, it is important to keep the roots moist and protected before planting. One
method is to store them in a mulch-filled plastic container or bag in a cool,dry place. Before planting,
bare roots should be temporarily submerged (one to two hours) in a bucket of water to stay moist until
they can be placed in the ground.To plant, make a hole large enough to insert the root system without
crowding or bending.Turned up roots may kill the plant. Cover roots completely with soil so that the soil
surface is at the same level on the stem as it was in the nursery. If this isn't obvious, plant the first set of
lateral roots no deeper than one inch below the soil surface(Figure 2). Pack soil firmly and tamp to
remove air pockets.
Planting containerized seedlings is similar to planting bareroot seedlings. Unrooted cuttings need to be
placed in the ground with only two to three buds remaining above ground.Avoid planting seedlings in
extremely dry, hot or windy conditions. Heat and wind can quickly dry out leaves and roots.Water the
soil around the seedlings immediately after planting.
Installing Grasses
Preparing the Site. It is essential to manage weeds and erosion before, during and after planting
grasses. In general,weeds are controlled with chemicals, mowing, or hand picking.An effective
approach is to plant Roundup Ready®soybeans the year before the grass buffer is installed.Although
soybeans don't provide as much residue as corn,grass can be easily planted into the residue. Weed
control can be improved by using a glyphosate herbicide the year before grass planting.
Seeding. For a CCRP buffer grass seeds must be planted at a rate of 40 pure live seeds(PLS) per square
foot by broadcasting or drilling. Broadcasting involves spreading seeds on the ground and then
incorporating them with light tillage. Mechanical drilling involves inserting the seed directly in the
ground at a uniform depth. Drilling provides more accurate seed placement and is the preferred
method.
One common reason for grass establishment failure is placing the seed too deep in the ground.A drill
can ensure that the seeds are placed only 1/4-to 1/2-inch deep.The mechanical drill does three things:
1)cuts and handles the residue, leaving some on the ground during planting for erosion control; 2)
inserts the seed 1/4-to 1/2-inch deep; and 3) covers the seed to ensure good seed-soil contact.
Seed sizes and weights vary;therefore,application rates vary.Grass drills can be calibrated to meter
different types of seeds and seeding rates. For example, a common warm season mixture consists of
Indiangrass, big bluestem, and switchgrass. Indiangrass and big bluestem are fluffy seeds and
switchgrass is a small smooth seed. If you want to plant these seeds, it can be done correctly with a drill.
Indiangrass and big bluestem fluffy seeds need to be metered by a finger-type mechanism.The
switchgrass smooth seeds need to be metered by a fluted-type mechanism. Calibrate the drill for each
type of seed before use to ensure chat the metering mechanisms are releasing the right amount of seed.
In some areas,drills may be rented from your local Pheasants Forever chapter or your Natural Resources
District
Postplanting Care of Trees and Shrubs
Weed Control. Although weeds were destroyed before planting,they will reappear and compete with the
plants for water and nutrients and need to be controlled. Weeds growing between tree rows can be left to
protect small trees from hot desiccating winds and to provide wildlife habitat,but care needs to be taken
to ensure that weeds,and grasses, don't excessively compete with young trees. If grass is planted between
tree rows,remove weeds to ensure that the grass can get established(see the following section on
grasses).
Weed control is most critical in a three-to four-foot radius around a tree or shrub seedling because this is
where the roots will be growing. Control weeds with herbicides,mowing or by using a conservation
mulch. When using herbicides near tree and shrub areas,make sure the chemical will destroy only the
desired weed species and not your trees and shrubs,and be aware of label restrictions for use of these
chemicals near bodies of water.Read labels carefully and check with the Nebraska Department of
Agriculture if you are unsure of use or label requirements.After trees and shrubs are established,weeds
need to be removed as necessary.
Mulches are an excellent means to reduce weed competition and conserve soil moisture.Straw or grass
may attract voles(which may feed on tree and shrub seedlings)and are not recommended for use as
mulch. Wood chip mulch should surround the plant at a three-to four-foot radius to a depth of four inches
to adequately retain moisture and reduce weed growth.Keep the mulch two to three inches away from
tree and shrub stems to prevent stem decay and pest problems.Black fabric mulch also can be used to
reduce weed growth.It is available in 4-by-4 foot squares or in 6-by-300 foot rolls.Fabric or woodchips
can be placed by hand or mechanically, if equipment is available.
Watering. Water newly planted trees one or two times per week,depending on rainfall.If no rain occurs,
apply two to five gallons of water per plant per watering,depending on plant size. Providing water during
dry periods for the first year or two is as important as site preparation and weed control.If you plant in a
dry year,provide water throughout the growing season.If it doesn't rain for several weeks and the soil is
dry two to three inches below the ground,provide water,but if the soil is moist two to three inches down,
water later.
Generally,deep less frequent watering is better than shallow frequent watering.Water is commonly
supplied manually from a water tank on the back of a truck or trailer.A five-gallon bucket with a small
hole in the side also can be used to water seedlings.Fill the bucket with water and set it next to a seedling.
The bucket will slowly release water into the soil and can keep the seedling moist for several weeks,
depending on the weather.
Postplanting Care of Grasses
Weed Control. The primary postplanting concern in grass planting is weed control.Use mowing or
herbicides to control weeds.If weed pressure is high,mowing or shredding may help,but to protect
wildlife,grasses should remain at least six inches tall after mowing.Use the proper herbicide for the weed
species you are trying to control, and note that warm season grasses require different herbicides than cool
season grasses.Check herbicide label restrictions for use near water and other plants.
It may take native grass species two to three years to get well established.First-year plantings may look
like a failure,but do not panic.Patience is needed for establishing a native grass buffer.
Long-Term Buffer Maintenance
While postplanting care is essential in getting a buffer established,long-term maintenance is also
necessary.Long term maintenance may include replanting damaged or dead shrubs,trees or grasses,
controlling weeds(described previously),harvesting,watering,protecting the buffer from damage by
livestock and wildlife,repairing eroded areas,and removing sediment deposited in the buffer.
Replanting. Occasionally,trees or grasses may have to be replanted in a buffer. Wildlife damage or
sediment deposition from erosion can kill trees,shrubs, or grasses.Vegetation can be replanted as desired
or as required by government program regulations.
Harvesting and Pruning. Periodic harvesting of stems from shrubs and pruning tree branches as well as
mowing grasses,can stimulate vigorous growth.Prune trees to remove dead,dying and broken branches.
If needed,thin trees prior to maturity to prevent overcrowding and reduced growth.
Watering. It may be necessary to provide water for high-value trees and shrubs during dry periods or
droughts to promote vigorous growth.Well-established trees and shrubs rarely need watering,except
during severe droughts.
Protection from Livestock. Livestock can trample and damage vegetation(stems and roots)and should be
kept out of buffers as much as possible,especially during establishment.Fencing may be needed to
protect high-value plantings.Grazing is usually not allowed in CCRP buffers.
Protection from Insects and Disease. Specialty crops,especially fruit and nut-bearing trees,should be
examined routinely to detect and treat insect and disease damage.Contact a local Cooperative Extension
or NRCS office or plant nursery for help with diagnoses and control options.
Repairing Eroded Areas. Inspect buffers annually and after severe rainfall events for signs of erosion.
Areas where grass is missing and where small channels or gullies have started to form should be repaired
as soon as possible.Fill with additional soil,regrade the surface and replant grass as soon as possible.
Removing Sediment. Buffers are designed to trap eroded soil,or sediment,that is carried in the runoff
water from crop fields.Over time,or after large rainfalls,this sediment can build up in the buffer and
bury vegetation.Buffers should be checked for sediment build-up annually and after severe rainfall
events. When sediment forms a ridge that blocks water from flowing into the buffer or concentrates water
flow through the buffer,the sediment should be removed or spread back on the field. If sediment
completely covers vegetation,grasses may need to be replanted after sediment removal or spreading.
Excessive soil movement from adjacent fields is a good indicator that additional erosion control measures
such as no-till,conservation till or terraces need to be used.
For more detailed information on buffer maintenance and protection from livestock and wildlife,refer to
NRCS Nebraska Technical Guide Notice 535 Section IV Tree/Shrub Planting Procedures.
Zone 1:Zone 1 will begin at the top of the streambank and occupy a strip of land with a fixed width of
15-feet measured horizontally on a line perpendicular to the streambank.The purpose of Zone 1 is to
create a stable ecosystem adjacent to the water's edge, provide soil/water contact area to facilitate
nutrient buffering processes, provide shade to moderate and stabilize water temperature encouraging
the production of beneficial algal forms,and to contribute necessary detritus and large woody debris to
the stream ecosystem. Dominant vegetation will be composed of a variety of native riparian tree and
shrub species and such plantings as necessary for streambank stabilization during the establishment
period.A mix of species will provide the prolonged stable leaf fall and variety of leaves necessary to
meet the energy and pupation needs of aquatic insects. Large overmature trees are valued for their
detritus and large woody debris. Zone 1 will be limited to bank stabilization and removal of potential
problem vegetation.
Zone 2:Zone 2 will begin at the edge of Zone 1 and occupy an additional strip of land with a minimum
width of 60-feet measured horizontally on a line perpendicular to the streambank.Total minimum width
of Zones 1&2 is therefore 75 feet.The purpose of Zone 2 is to provide necessary contact time and
carbon energy source for buffering processes to take place, and to provide for long term sequestering of
nutrients in the form of forest trees.Outflow from subsurface drains must not be allowed to pass
through the riparian forest in pipe or tile,thus circumventing the treatment processes.Subsurface drain
outflow must be converted to sheet flow for treatment by the riparian forest buffer, or treated
elsewhere in the system prior to entering the surface water. Predominant vegetation will be composed
of riparian trees and shrubs suitable to the site,with emphasis on native species, and such plantings as
necessary to stabilize soil during the establishment period.
Zone 3:Zone 3 will begin at the outer edge of Zone 2 and have a minimum width of 25-feet.Additional
width may be desirable to accommodate land-shaping and mowing machinery. The purpose of Zone 3
is to provide sediment filtering, nutrient uptake,and the space necessary to convert concentrated flow
to uniform,shallow, sheet flow through the use of techniques such as grading and shaping,and devices
such as diversions, basins,and level lip spreaders.Vegetation will be composed of dense grasses and
forbs for structure stabilization,sediment control, and nutrient uptake. Mowing and removal of
clippings are necessary to recycle sequestered nutrients, promote vigorous sod, and control weed
growth.Vegetation must be maintained in a vigorous condition.The vegetative growth must be hayed,
grazed, or otherwise removed from Zone 3. Maintaining vigorous growth of Zone 3 vegetation must take
precedence and may not be consistent with wildlife needs.
Vegetation Selection by Zone:Zone 1&2 vegetation will consist of native streamside and upland tree
species as identified on the following image. Deciduous species are important to be used in Zone 2 due
to the production of carbon leachate from leaf litter which drives bacterial processes that remove
nitrogen, as well as the sequestering of nutrients in the growth processes. In our climate,the use of
evergreens is also important due to the potential for nutrient uptake during the winter months. In all
riparian buffer planting projects, a variety of species is important to meet the habitat needs of insects
important to the aquatic food chain. Zone 3 vegetation should consist of perennial grasses and forbs.
Appendix 7 of the Chesapeake Bay Riparian Handbook provides detailed summary information on
choosing native plants for riparian buffers. Please consult the Resources section of this guide for more
information,as well as your local native nursery.
Maintenance:
The riparian buffer is subject to many threats, including herbivory, invasion by exotic species,
competition for nutrients by adjacent herbaceous vegetation, and human disturbance. Proper
maintenance is important to ensure the long-term effectiveness and sustainability of a restored riparian
buffer.The most critical period during buffer establishment is maintenance of the newly planted trees
during canopy closure,typically the first 3 to 5 years.Ongoing maintenance practices are necessary for
both small seedlings and larger plant materials. Maintenance and monitoring plans should be prepared
for the specific site and caretakers need to be advised of required duties during the regular maintenance
period.
Maintenance measures that should be performed regularly:
1. Watering
• Plantings need deep regular watering during the first growing season, either natural
watering via rainfall,or planned watering,via caretaker.
• Planting in the fall increases the likelihood of sufficient rain during planting
establishment.
2. Mulching
• Mulch will assist in moisture retention in the root zone of plantings, moderate soil
temperature,provide some weed suppression, and retard evaporation
• Use coarse,organic mulch that is slow to decompose in order minimize repeat
application
• Apply 2-4 inch layer, leaving air space around tree trunk to prevent fungus growth.
• Use combination of woodchips, leaves, and twigs that are stockpiled for six months to a
year.
3. Weed control Weed competition limits buffer growth and survival,therefore weeds should be
controlled by either herbicides or mowing:
• Herbicides:This is a short-term maintenance technique (2-3 years)that is generally
considered less expensive and more flexible than mowing, and will result in a quicker
establishment of the buffer. Herbicide use is regulated by the PA Department of
Agriculture. Proper care should be taken to ensure that proximity to water features is
considered.
• Mowing: Mowing controls the height of the existing grasses,yet increases nutrient
uptake,therefore competition for nutrients will persist until the canopy closure shades
out lower layers. A planting layout similar to a grid format will facilitate ease of mowing
yet yield an unnaturally spaced community. Mowing may result in strikes on the trunk
unless protective measures are utilized. Mowing should occur a maximum of twice each
growing season. Mower height should be set between 8—12 inches