HomeMy WebLinkAboutJohn Burger 03.20.19 BMP for Lead at Outdoor Shooting Ranges
placed over the shotfall zone during non-use Examples of"hard" controls include:
periods. This provides the range with two
benefits during periods of rainfall: (1)the shotfall / Filter beds _ \
zone is protected from erosion; and (2)the spent ► Containment Traps and Detention Ponds
lead shot is contained in the shotfall zone and / Dams and Dikes
does not come in contact with rainwater. ► Ground Contouring.
Designing and implementing these"hard" `i
Permanent Surface Covers engineering controls may require the assistance
of a licensed professional civil engineer. They 1',
For outdoor rifle and pistol ranges, impact are included in this manual to offer the reader a
backstops and target areas can also be covered
general understanding of these BMP options.
with roofed covers or other permanent covers to %
However, this manual does not offer specific
prevent rainwater from contacting berms. instructions for construction and operation of
However, this method may be less desirable these controls. For information about designing
because of the cost to install the roof, which and implementing any of these controls, or
must be carefully designed to avoid safety assi`stance with other range design questions,
issues with ricochets, etc. contacea licensed professional civil engineer ,
having app icable experience or the N`RA" ange /
For shotgun and other ranges, synthetic liners Department, at (800) 672-3888, ext. 1417. The f
(e.g., asphalt, Astroturf' , rubber, other synthetic National Sports Shooting Foundation (NSSF)
liners) can also be used beneath the shotfall may be contacted at (203) 426-1320 for specific ill
it
zone to effectively prevent rainwater or runoff references regarding the use and design of
from filtering through lead and lead these controls.
contaminated soil. Synthetic liners will generate it'
increased runoff, which must be managed, Filter Beds
however. No single type of liner is suitable for all
situations based on site characteristics. Filter beds are engineering controls built into an
Therefore, liners must be chosen on a site- outdoor range to collect and filter surface water
specific basis, bearing in mind the site's unique runoff from the target range. The collected
characteristics, such as soil type, pH level, runoff water is routed to a filtering system, which
rainfall intensity, organic content of soil, and screens out larger lead particles, raises the pH
surface water drainage patterns. of the water(thus reducing the potential for
,ifurther lead dissolution), and drains the water
Engineered Runoff Controls from the range area. This technique may not
completely prevent lead from entering the
Runoff control may be of greatest concern when a range is located in an area of heavy annual rainfall because of an increased risk of lead subsurface, since lead bullets, fragments and
large particles may still remain on the range.
migration due to heavy rainfall events. A"hard" Filter beds should be established at the base of
engineered runoff control may be needed in this the backstop (see Figure 3-2). In addition to
i situation. A heavy rainfall event is defined as mitigating off-site migration, the filter beds work
rainfall that occurs at such a rate that it cannot to raise the pH of the rainwater, which has fallen
be absorbed into the ground and causes an on the target range, to reduce lead dissolution,
increase in the volume and velocity of surface and to strain small lead particles out of the
runoff. The impacts of rainfall are greater in rainwater. The filters typically consist of two
rolling or sloped terrain (increases velocity of layers: a fine-grained sand bed underlain by
runoff) or where surface water bodies are limestone gravel or other neutralization material.
'; located on, or immediately adjacent to, the By design, the backstops and berms direct the
range. runoff so that it drains from the range to the
filters. The collected water then soaks through
the top sand layer into the neutralization material,
Chapter III - Page III-9
BMP for Lead at Outdoor Shooting Ranges
Phosphate Addition Other Ways to Bind Lead
In addition to lime spreading, another way to Although it may be possible to minimize lead's
control lead migration is phosphate spreading. mobility by spreading fertilizers that contain
This method is recommended where lead is phosphate at impacted areas of the range, a
widely dispersed in range soils, a range is more comprehensive procedure for immobilizing
closing, or there is a high potential for vertical leachable lead in soils, by using pure phosphate
lead transport to groundwater(e.g., low soil pH, in rock form or a ground phosphate rock [Triple •
shallow water table). Under these Super Phosphate (TSP)], was developed and
circumstances, range soils may benefit from t patented by the U.S. EPA/Ohio State University
phosphate treatment. Unlike lime spreading, the Research Foundation and RHEOX, Inc. This
main purpose of phosphate spreading is not to procedure used a three step approach to
adjust soil pH but to bind the lead particles. This minimize lead's mobility. The first step was to
process also decreases the potential amount of identify the boundaries of the area of the range to
lead that can migrate off-site or into the be treated. This included not only determining
subsurface. Phosphate spreading can be done the length and width of the range area, but also
either separately or in conjunction with lime the depth of lead within the area.
spreading. Generally, 15 to 20 pounds of
phosphate per 1,000 square feet will effectively Depth was determined by taking sample cores
control the lead. of the area, which also identified"hot spots"
1,1, where lead accumulation was greatest. Once
Phosphate spreading is especially the area was identified, the second step was to
recommended for sporting clays ranges and \ treat the area with TSP. Pure phosphate rock
those parts of ranges not easily accessible by was used rather then fertilizers, as this
reclamation equipment. Phosphate spreading phosphate is insoluble in water and will not
should be repeated frequently during the range's ' cause an increase in phosphate runoff.
lifetime. See pilot testing under"Other Ways to
Bind Lead" below for proper frequency for In this step, pilot testing was conducted. Here,
replacing phosphate. various amounts (in increasing percentages by
weight) of TSP were added to the affected soil
You can purchase phosphate either in its pure areas, then the area was tested according to an •
form, as phosphate rock, or as lawn fertilizer. EPA test method that identified the amount of
The average lawn fertilizer costs approximately leachable lead in a given soil sample. This test
$7.00 per 40 pound bag. If you purchase lawn is called the Toxicity Characteristic Leaching
fertilizer, remember to check the bag for the Procedure, or TCLP. Separate TCLP testing of
actual percentage of phosphate. Most fertilizers the range's hot spots was conducted.
contain 25% phosphate, so that if you purchase
a 40 pound bag of fertilizer that contains 25% Upon completion of the pilot testing, which
phosphate (i.e., 10 pounds of phosphate) you determined the amount of TSP needed at the
will need to spread 80 pounds of fertilizer per range, the third step was to begin actual
1,000 square feet of the backstop. A typical treatment of the range. Where the depth of the
fertilizer drop spreader can be used for lead accumulation was shallow (less than two
distributing the phosphate. Like lime, phosphate feet), then standard yard equipment, such as
should not be spread when the ground is frozen. tillers, seed/fertilizer spreaders, and plows were
In addition, it is not advised to use phosphate used to mix TSP with the affected soil. Where
near water bodies since it contributes to algal the affected area's lead accumulation was
blooms. Rock phosphate is a better choice if deeper than two feet, an auger was required to
water is nearby. mix the TSP with the affected soil. Random
testing of the range ensured the effectiveness of
the treatment level.
Chapter III - Page III-7
BMP for Lead at Outdoor Shooting Ranges
Berm/Backstop
Vegetative Ground Cover
Runoff Direction
\..........a, .
Perforated
Sand Layer °: "o: Pipe
Limestone! '_ •
kat O n
Gravel Layer
Figure 3-2-Sample Filter Bed System (Adapted from Proceedings for National Shooting, Range Symposium,
October 17-19, 1993,North American Hunting Club and Wildlife Forever)
which raises the pH of the filtrate. The lead of containment traps and ponds by further
particles in the rainwater are collected on the reducing the velocity of runoff and allowing for
sand, while the pH-adjusted water drains more lead fragments to settle from the runoff. It
through the filter to a perforated drainage pipe is important to regularly collect the lead and send
located within the limestone gravel. this lead to a recycler.
Filter beds are designed to capture fine particles Dams and Dikes
of lead transported in surface water runoff.
They are not designed to capture bullets. The At shotgun ranges, dams and dikes can also be
operation and maintenance requirements of filter used to reduce the velocity of surface water
beds are minimal. Maintenance activity is limited runoff. Dams and dikes must be positioned
to periodic removal of debris (such as litter, perpendicular to the direction of runoff to slow
leaves, etc.) and occasional replenishment of the flow of surface water runoff. To accomplish
the limestone. this, determine the direction of the range's
surface water runoff. This will be particularly •
The use of filter beds is most effective on sites obvious at ranges with sloped terrain. The dams
with open, rolling terrain where surface water or dikes should be constructed using mounds of
runoff is directed to them. At existing rifle and dirt that are approximately a foot high. These
pistol ranges, a limited system of trenches and mounds should transect the entire range
filters can be installed at the base of natural soil perpendicular to the stormwater runoff direction.
backstops or at natural drainage depressions.
These runoff controls are most important at
Containment Traps and Detention Ponds ,� ranges which off-site runoff is a potential
problem, such as ranges where the lead
Containment traps and detention ponds are accumulation areas are located upgradient of a
designed to settle out lead particles during ' surface water body or an adjacent property.
heavy rainfall. Typically, they are depressions Since lead particles are heavier than most other
or holes in the range's drainage paths. Here, suspended particles, slowing the velocity of
the lead-containing runoff passes through the surface water runoff can reduce the amount of
trap or pond, allowing the lead bullet fragments lead transported in runoff.
to.settle-out. Vegetative cover can be placed in
the drainage path to increase the effectiveness
Chapter III - Page III-10