LIVING ON KARST
Page 2
A REFERENCE GUIDE FOR LANDOWNERS IN LIMESTONE REGIONS
7/15/00
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8 Menu
Defining Pollution
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Pollution is an undesirable change in the
physical, chemical, or biological characteristics of air,
land, or water that adversely affects the living
conditions for humans or other living organisms.
Water pollution is an overabundance of one or
more natural or manmade substances in a body of
water. Natural pollutants from soils and bedrock
include sulfur, radon, and iron deposits; tannic acid and
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methane gas come from marshlands.
People generate a host of wastes and pollutants that
must be dealt with. The U.S. Environmental
Protection Agency classify the two major types of
manmade pollutants as point source pollution and
nonpoint source (NPS) pollution.
Point Source Pollution
comes from a single source, such as a pipe, culvert, or ditch.
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Point source pollution is commonly associated
with industrial sites, waste and water outflow pipes,
or sewage treatment facilities. The signs of
pollution that most people can identify are a strong
odor, discharges of multicolored liquids or foam
from pipes, algal growth in streams and springs
resulting from sewage and other wastes, discharges
from smokestacks, and refuse dumps.
Point source pollution is generally controlled through state and federal
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permits which require
a minimum level of treatment, and filtration
before wastes can be discharged to surface water.
Nonpoint Source (NPS)
Pollution>
presents a more subtle water quality problem because
it originates from widely dispersed and diverse sources, not a single outlet. Natural forces such as rain or wind often play a key role in transporting NPS pollutants to streams and aquifers. Examples of NPS pollution include sediment from eroded fields and construction sites, and runoff
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from backyards and barnyards containing fertilizers, pesticides,
and animal wastes. Other examples of NPS pollution are the disposal of waste motor oil, paint thinner, and antifreeze in ditches and storm sewers. This also includes various pollutants attached to particles that wash off streets and parking lots. NPS pollution is even draining chlorinated swimming pools into storm sewers or streams.
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Pollution continues to enter streams
and groundwater in many subtle ways.
NPS Pollution is the major threat to our
water supply:
Sediment
Soil particles eroded from the land are carried
by rainwater to aquifers, streams, lakes, rivers,
and bays. Metals and nutrients, such as
phosphorous, attach to sediment and are carried into these
water bodies by runoff.
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Trash and Organic Debris
Leaves, grass clippings, garbage, and animal
waste become part of the runoff entering storm
drains, sinkholes, and drainage ways, clogging the underground conduit system.
Nutrients
Fertilizers and animal wastes contain nutrients
that are essential to life, but too much can do more
harm than good. Nutrients can readily enter runoff and
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impact water quality.
Chemicals
Man made chemicals can cause severe human
and wildlife health problems. The use and disposal
of synthetic organic compounds, metals,
pesticides, herbicides, household chemicals, paint,
solvents, petroleum products, antifreeze, battery acid,
and roadway salt should be carefully controlled.
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9 Menu
Erosion and Sediment Control
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Why Be Concerned about Erosion?
Erosion occurs when rain or flowing water dislodges and transports soil particles, organic matter, and plant nutrients. Erosion carries away soil resources, reduces soil fertility, and produces thousands of tons of sediment that degrade water quality. Soil and sediment may convey pesticides,
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harmful bacteria, toxins, and nutrients into surface waters and groundwater. Flooding, habitat destruction, and subsidence increase when eroded soil and debris clog creeks, caves, sinking streams, springs, sinkholes, and drainage ways. To reduce erosion and sedimentation, karst features must be identified and receive special protection from erosion impacts.
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Signs of Erosion, Sedimentation and Subsidence include:
• Bare soil and cracked earth in and around sinkholes, roads, and building foundations.
• Exposed roots of trees and vegetation
• Gullies carved into banks, slopes, and ditches
• Silt buildup, fresh mud deposits, and muddy water
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• Widening and subsidence of stream channels and drainage ways
• Undercut stream banks and fallen trees along drainage ways
Keep Erosion and Sediment Under Control.
Proper land management practices hold soil and nutrients in place and keep sediment, nutrients, and pesticides out of watercourses. Specific best management practices include:
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• Conservation and Contour Tillage
Any farming or planting method that utilizes the most level lay of the land and keeps plant residue on the soil surface during critical erosion periods.
• Construction Planning
Any building project that disturbs the soil can create an erosion and sediment problem.
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In cooperation with your county Erosion and Sediment Control Administrator, proper planning and design can prevent or minimize erosion, sedimentation,
flooding, and subsidence in karstlands. Stay away from active karst features such as sinking streams, sinkholes, and lands on top of caves.
• Critical Area Planting
As soon as possible, reseed disturbed areas with temporary and/or native
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vegetation. Plant rigorous cuttings on bare, undercut, and eroding areas around sinkholes, springs, stream banks, and drainage ways. Maintain vegetated filter strips or grassed waterways down slope of agricultural or construction operations to slow and disperse water evenly over a large area, and to allow the natural removal of sediment, organic matter, and other pollutants carried in the runoff.
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• Proper Drainage
Avoid rerouting waterways and drainage patterns in karst. Altering surface flows into sinkholes can cause erosion in the subsurface which results in sudden land collapse or subsidence. Ditches should be lined in areas near caves. Use silt fences to protect karst features and water resources from erosion and sedimentation until vegetation is established.
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• Temporary Structures
Protect adjacent property and sensitive springs or streams by constructing silt fences across ditches and drainage ways. These must be inspected frequently and cleaned out after each rain event.
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Silt Fence
A temporary sediment barrier consisting of a synthetic filter fabric stretched across and attached to supporting posts and entrenched.
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10 Menu
The Problem with Stormwater Runoff
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Runoff : The water from rain or melted snow that does not infiltrate the soil but flows over
the land surface; precipitation drainage.
Everything that goes into a storm drain, flows out into the groundwater, streams, lakes, or river.
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In karst areas, sinkholes are nature's storm drains, and the dissolved caves
beneath are like nature's piping system. As groundwater moves through the earth, wide open spaces such as caves can carry thousands of gallons of water at a time. This groundwater reemerges on the surface as springs or through wells.
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Each time trash, motor oil, anti-freeze, litter, pet waste, fertilizer, yard and garden debris, household chemicals, and road sand and salt are dumped on the ground or washed into storm drains, drinking water, groundwater, and aquatic life are endangered. With every
rain or snow these pollutants can be carried into the groundwater/surface water system.
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What You Can Do at Home
• Never dump anything into a storm drain or sinkhole.
• Recycle motor oil at a local gas station.
• Use fertilizers wisely. Have soil tested to determine proper amounts.
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• Keep pesticide use to a minimum. Use least toxic alternatives.
• The size and shape of the vegetated zone needed will depend on the slope of
Maintain vegetation on steep slopes to keep soil in place.
• Compost yard and garden debris.
• Do not overfill car radiators and fix leaks.
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Pollution from Rooftops
Roof runoff contains water pollutants such as bird droppings, chemicals from roofing materials, and heavy metals leached from gutter. In an EPA study, roof runoff was one of the most toxic samples collected.
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In karstlands, uncontrolled or altered runoff can cause structures to be undermined, resulting in subsidence or damage.
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11 Menu
Reducing Runoff Pollution in Karst Areas
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Common Runoff Pollutants
• Heavy metals (lead, copper, zinc, chromium) from gasoline, tires,
corroded metal, paint, wood preservatives, and motor oil.
• Pesticides and fertilizers from yards, foundations and gardens.
• Bacteria from sewage and animal wastes.
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• Soil sediments from construction sites, bare stream banks, home landscaping, and steep exposed slopes.
Prevention
Prevention is the best cure. The pollution potential in karst areas is very high. Streams and surface runoff entering sinkholes and storm drains
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contribute to the recharge of groundwater aquifers, providing direct conduits for contaminants.
Changes in Water Flow
Urban development and growth may cause water quality problems. Stormwater Management, erosion control strategies, and riparian zone management need to be carefully considered. The traditional methods of large-and small-scale
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development paid little attention to the number of impervious surfaces that were created, such as roofs, sidewalks, streets, and parking lots. Rain runs rapidly off of the these surfaces, turning city streams into raging torrents that cause erosion and damage property.
Sediment
Bare construction sites allow large amounts of fine soil, or sediment, to erode away. Other pollutants often
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Basic Runoff Controls
Well-designed runoff controls can be smart, cost-effective, aesthetically pleasing, and for businesses, satisfy local requirements for green spaces. There are many easy and affordable ways to reduce harmful stormwater runoff, make your living or working environment more pleasant, and enhance property values, all at the same time.
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• Maintain as large a vegetated zone as
possible on drainage ways and slopes to
slow runoff and filter out pollutants.
• Slow runoff by building check dams
across ditches and using vegetated
sinkholes to naturally detain water and
allow soil and pollutants to settle out.
• Keep soil on site during construction
by using silt fences, hay bales, and
sedimentation basins.
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12 Menu
Pasture Land or Grassland Management
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Studies conducted on a nationwide scale which included karst regions, indicate that farmland contributes to a general decline in surface water and groundwater quality. Public programs to address agricultural runoff concerns are focussed on the largest commercial feed lots and dairy operations, but small, independent livestock producers and farmers also can cause problems locally
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(and downstream). By limiting overgrazing and restricting livestock access to streams, farmers can conserve valuable soil fertility and minimize the amount of sediment and nutrients introduced into he watershed. In heavy use areas, such as winter feeding sites, barn lots, ponds, and any place where bare soil is exposed, sufficient vegetation should be
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established to retain sediment, soil particles, and manure on the fields. Work on stabilizing problem areas during the spring and summer months in order to reduce erosion aggravated by wet, winter weather and storms. Animals should have access to shady loafing areas located away from water bodies.
• Don't let the size of your herd exceed the carrying capacity of your soil and water resources. Practice rotational grazing techniques by leaving some pasture "in reserve" for livestock to graze when grass on other pastures is spent. The most heavily grazed fields may need to rest and recover occasionally in
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13 Menu
Erosion and Runoff in the Home Landscape
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• Soil erosion occurs when soil particles are
carried off by water or wind and deposited somewhere
else, such as into a stream or at the bottom of a
sinkhole. Soil particles and pollution are carried by runoff
- water that does not soak into the ground, but
flows over the surface and runs to another area, such
as into storm drains, sinkholes, or streams.
Controlling erosion and runoff takes a dedicated effort, but
will significantly reduce water pollution and protect and
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save the soil.
Signs of Erosion and Runoff
• Tree roots, small stones, or rocks
become exposed.
• Small rills, gullies, or unsightly bare
soil areas develop.
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• Soil splashes on windows and outside walls.
• Sediment and mud deposits collect in
low areas or on lawns, sidewalks, and driveways.
• Even short rain events leave water
flowing over the soil surface or standing in low spots.
Good Reasons to Control Erosion and Runoff
• Runoff can wash sediment, fertilizers,
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and pesticides into surface streams and sinking streams, contributing to both surface water and groundwater pollution.
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Erosion removes valuable topsoil and
clogs waterways, reservoirs, and spring basins
with sediment.
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Runoff can contribute to flooding
problems on adjacent properties when runoff from paved
and/or eroded areas is diverted into sinkholes.
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Erosion and runoff can increase the risk of sinkhole collapse
in karst areas.
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Landscapes to Control Erosion and Runoff
• Landscaping with grasses and ground covers not only adds beauty and value to
your property, but also helps control erosion by
reducing the amount and speed of runoff.
• Landscape yards to minimize rainwater
run-off. Preserve surrounding trees and vegetation
to the extent possible.
Plan Ahead>
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Steep slopes can easily be eroded and, even if erosion is controlled, may allow water to collect in undesirable areas, such as near house foundations and around wells.
Plan ahead to avoid drainage and erosion problems, and minimize ground disturbance, and plant a vigorous ground cover to reduce erosion and increase water penetration into the soil on the slope.
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14 Menu
Pesticides on the Home and Farm
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• Pesticides- insecticides, herbicides,
rodenticide, and fungicides - are chemicals widely used
by farmers, foresters, exterminators, and
homeowners to kill harmful insects and weeds, to increase
crop and timber harvests, and to prevent the spread
of plant, animal, and human parasites and diseases.
• Although targeted at pests, certain pesticides
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inadvertently can harm nontarget organisms
- stream insects, fish, wildlife, domestic animals,
and humans. Pesticides can also contaminate the groundwater if not handled carefully. Pesticides
can reach groundwater very quickly in karst areas due
to the porous rock, sinkholes, springs, and caves.
• Taking voluntary action to prevent pesticide
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contamination of groundwater will help assure
the continued availability of pesticides for
responsible use. Drinking water is least likely to be
contaminated if appropriate management procedures are
followed or pesticide wastes are properly disposed.
• Understanding the soils on your lawn, garden,
or farm and developing natural and appropriate chemical strategies can keep chemicals
from leaching into your groundwater. Soil types
vary widely within short distances, so several
samples should be collected and analyzed in order to
fully characterize the soils. Contact your county
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Cooperative Extension Agent for information on
soil sampling and analytical services.
• The correct use of pesticides and herbicides,
and reducing the amount of pesticides and
herbicides used can create a cost savings for the landowners.
• Avoid pesticide problems by using integrated
pest management practices. Such programs use chemicals only when necessary, in tandem
with other practices like crop rotation, timed
plantings, and appropriate growing conditions, to
protect crops from weeds, insects, or diseases.
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Pesticide Handling Rules
• Read and follow the label carefully.
• Buy only the quantity needed.
• Choose the least toxic pesticide. Those with
the signal word Caution on the label are considered
the least toxic, whereas the signal word
Warning indicates moderate toxicity.
• Wear any protective clothing specified on the product label and wash hands immediately after application.
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• Apply only the amount specified on the
product label and only on the plants and areas listed in
the instructions.
• Make sure people and pets are out of the
area during application and until the spray has dried.
• Never apply to bare ground or eroded areas
• Never store, mix, or apply near wells, streams, sinkholes, ponds, or marshes. Maintain buffer zones around these areas.
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• Avoid back-siphoning from sprayer equipment
into wells by always keeping the discharge end of
fill hoses above the tank's water level.
• Before disposing of chemical containers,
triple rinse or pressure rinse them and place the
liquid rinsate into the spray tank to make up the final
spray mixture.
• Prevent spills from reaching groundwater by using
a mix pad with low walls to contain spills and overfills. |
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• Don't apply if rain is forecast, unless specified
on the label (some pesticides do need to be
watered after application).
• Dispose of containers and leftover
pesticides according to label directions.
• Store all pesticides away from the reach
of children.
• Use a "water only" nurse tank in the field - away
from water sources and sinkholes - to provide water
for mixing agricultural chemicals.
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Living on Karst Above Menu.
© Cave Conservancy of the Virginias 2000. All Rights Reserved.
All Proprietary rights are reserved by the photographers.