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A User’s Guide to
Karst and Sinkholes in
Western Maryland
By Topper Sherwood
WESTERN MARYLAND RC&D18450 Showalter Road, Suite 111
Hagerstown, MD 21742-1383Voice: (301) 733-2973Fax: (301) 733-7643
E-mail: [email protected]: users.erols.com/wmarylandrcd/
PUBLISHED: JANUARY 2004
This guide was published with funding from the Chesapeake Bay Small Watershed GrantsProgram of the National Fish & Wildlife Foundation (www.nfwf.org/). Thanks to all the par-ticipants in Western Maryland RC&D-sponsored meetings on karst and sinkholes in ourregion: Mark Seibert, NRCS District Conservationist, Frederick Field Service Center; TomDevilbiss, Hydrogeologist, Carroll County; Tom Gray, GAI Engineer, Pittsburgh, PA; SabrinaAlbright, Western Maryland RC&D; Ann Brown, Frederick County Grants Office; EdSanders, Maryland Department of Agriculture; Gerald Baum, Maryland Geological Survey;Liana Dunne, Maryland Geological Survey; David K. Brezinski, Maryland GeologicalSurvey; Paul Petzrick, Maryland Department of Natural Resources; Douglas A. Valentine,NRCS District Conservationist, Carroll Field Service Center; Jim Schlossnagle, NRCSDistrict Conservationist, Washington County Field Service Center; Terry Welsh, NRCS SoilConservation Technician, Frederick Field Service Center; and Dawn Early, Soil ConservationDistrict Manager, Frederick Field Service Center. Special thanks for their attention to andcomments on this guide to: Tom Devilbiss; Western Maryland RC&D Secretary-TreasurerPaul Edwards, and Carl Robinette, NRCS District Conservationist, Allegany Field ServiceCenter, and many county employees in the region.
This guide was printed on 100% recycled paper by HBP, Inc. in Hagerstown, MD
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A User’s Guide to
Karst and Sinkholes in
Western Maryland
By Topper Sherwood
Western Maryland Resource Conservation & Development
Council, Inc.
Hagerstown, MD
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INTRODUCTION: Why This Guide? 3
What is Karst Topography? 4
Maryland’s Karst and Sinkholes 5
Karst, Land Use, and Water 5
Myths & Facts about Karst & Sinkholes 8
Problem : Runoff 9
What You Can Do 10
Septic Systems and Karst 10
What You Can Do 11
Protecting Well Water 11
What You Can Do 13
Sinkholes and ZOIs 13
Dealing with Problem-Causing Sinkholes 14
Agriculture on Karst 15
What You Can Do 16
MACs & BMPs 15
What To Do If You Suspect a Sinkhole 16
Local Resources 19
Resources for Disposing of Household Waste 21
Note: The photos in this guide are of Western Maryland karst and sinkholes. The back cover, however,shows an enormous Mexican sinkhole, El Sotano de las Golondrinas (“Cellar of the Swallows”).
CONTENTS
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This guide was written to help peoplewho live and work in Maryland to bemore aware of the issues presented bykarst topography, a geological terrainwhose most well-known characteristicsare solution cavities, caves, andsinkholes.
The developers of this guiderepresent local agencies that assistresidents and business owners withquestions about land, water, and karst.We work to help others understand thenature of land and water in our region,and to become more aware of the needfor good conservation practices. We havedeveloped this guide to be of specificuse to:
• residents — farmers and homeowners who live and work in karst areas;
• mortgage and real-estate professionals;
• state and local policy makers and planners;
• insurers;• educators;• members of the media; and• construction and utilities
contractors.Questions about karst and sinkholes
can be directed to members of theagencies listed on pages 16-20 of thisguide. Questions and comments aboutthe guide itself should be forwarded tothe Western Maryland ResourceConservation & Development Council(RC&D).
The Western Maryland RC&D isgrateful to all the partners who havejoined in the development of the guide,which was supported by a ChesapeakeBay Small Watersheds Grant from theNational Fish & Wildlife Foundation(www.nfwf.org).
We are also grateful to those whoread this guide, those who use theinformation offered here, and to thosewho share it with others.
INTRODUCTION: WHY THIS GUIDE?
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WHAT IS KARSTTOPOGRAPHY?
“Karst” describes terrain that’scharacterized by sinkholes, caves,underground streams, and other featuresthat are formed by the slow dissolution ofcalcium and magnesium oxides inlimestone, dolomite, or marble bedrock.Karst landscapes are often spectacularlyscenic areas. Examples include thesinkhole plains and caves of centralKentucky, the large crystal-clear springsof Florida, and the complex, beautifullydecorated caves of New Mexico. Karstterrains are areas of abundant watersupplies, limestone quarries, and minerals.In the United States, 20 percent of theland surface is karst and 40 percent of thegroundwater used for drinking comesfrom karst aquifers.
People who settle in karst areas,however, can find themselves dealing withassociated problems. Karst regions can beprone to unpredictable or easilycontaminated groundwater supplies orunusual surface water drainage. Karstlandscapes are also among the mostsusceptible to environmental impact,including ground subsidence. Followingstorms, droughts, and changes in land use,sudden subsidence features known assinkholes, can cause damage to buildings,roads, parking lots, and farmed land.
In unpopulated and undeveloped areas,a sinkhole may pose little or no danger. Inpopulated and developed regions,however, sinkholes are more likely tocause problems. They present us with twokinds of hazard: 1) the physical danger of
falling into them, as well as the danger tostructures — buildings, roads, airportrunways, etc.; and 2) the threat to groundand surface water quality by the potentialfor direct introduction of contaminants.People living and working in karst regionsneed to be particularly sensitive to issuesof land use and water quality protection.
The stakes are high for communitiesconfronting the physical danger ofsinkholes. Recent collapses have beenoccurring along Interstate 70, in FrederickCounty, and one sinkhole that openedsuddenly on a state highway in CarrollCounty in 1994 caused a fatal autoaccident there. Sinkholes appearing infields have injured livestock and damagedfarm equipment. The threat to waterquality is well documented and can pose asignificant and quick hazard. Streamwater or surface runoff that enters asinkhole or cave can bypass naturalfiltration through soil and sediment.Groundwater can travel quite quicklythrough these underground networks —upto thousands of feet per day — carryingsurface contaminants to wells and springs.
We will discuss this issue further in thesection on water quality, beginning onpage 5.
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MARYLAND’S KARSTAND SINKHOLES
Where are Maryland’s karst areas?The most-affected counties areWashington, Carroll, Frederick, andBaltimore, with less extensive areas inAllegany County. (See Figure 1. below)While we cannot know every detail ofwhat lies in the ground below everypiece of property, geologic mapping bythe Maryland Geological Survey (MGS)has provided an excellent understandingof Maryland’s subsurface. [For access toMGS maps and other information, visitwww.mgs.md.gov.]
Soil surveys conducted by theNational Cooperative Soil Survey alsoprovide clues to potential areas ofsinkhole development. Soil mapsidentify areas where soils originate fromor overlie limestone and other materialwith some potential for developingsinkholes. To access soil survey mapsand interpretive information, visitwww.sawgal.umd.edu/nrcsweb/Maryland/index.htm and navigate to a particularcounty. [The current Frederick CountySoil Survey (2002) contains a soil-
interpretation table outlining the relativepotential for sinkhole formation by soilseries.]
MGS staff members estimate thatFrederick County alone contains avulnerable karst topography coveringabout 35 square miles. WashingtonCounty is estimated to have a karst areaof two or three times that size. TheGeological Survey has identified morethan 1,000 “karst features,” including125 sinkholes, in a relatively smallportion of Frederick County. From this,we know that hundreds of sinkholes arelikely to exist in each of the three most-affected counties, Washington,Frederick, and Carroll.
Karst, Land Use, and WaterQuality
All uses of land affect an area’sgroundwater. Those of us who live andwork in karst country, however —homeowners, real-estate professionals,public planners, farmers, or contractors— should be especially aware of theterrain’s tendency to form sinkholes andthe implications for our water resources.
Most karst areas areunderlain by limestonewhich may be composedof varying degrees ofopenings. Sometimeslarge, sometimes smallmost have the ability to
transmit waterand soil.Sinkholes
occur when a
Figure 1
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“bridge” of loose stones and soilcollapses into a fissure or opening in therock, sending surface material and waterinto underground cavities. (See Figure 2on the opposite page.) Such sinkholecollapses occur naturally; they also maybe prompted by human activity. Exampleswould be ponding water, extractinggroundwater for water supply orquarrying, blasting, grading or soildisturbance.
Some common features that may warnof eventual sinkhole collapse include:
• Circular and linear cracks in soil,asphalt, and concrete paving or floors;
• Depressions in soil or pavement that commonly result in the ponding of water;
• Slumping, sagging, or tilting of trees, roads, rails, fences, pipes,poles, sign boards or other structures;
• Downward movement of small-diameter vertical structures such as poles or posts;
• Fractures in foundations and walls, often accompanied by jammed doors or windows;
• Small conical holes appearing onthe surface of the ground during a relatively short period of time;
• Sudden muddying of water in a well that has been producing clear water; or
• Sudden draining of a pond or creek.
An open sinkhole—as big as a house,or as small as a coffee mug—may carry
untreated surface water, directly andimmediately, to local aquifers affectingany number of springs, and well sources.Sinkholes may threaten water quality,for example, when they occur nearunderground water and sewage systems.Karst-area water resources and wellshave been damaged by cracked sewerlines, and drain fields placed wherenatural soil filtration can be bypassed.There have been accidental orinadvertent discharges from gas stations,treatment plants, and other facilities withunderground storage tanks andassociated piping causing materials toleach into and move quickly through thekarst subsurface, polluting local watersupplies. In the worst cases, sinkholeshave been used as dumping grounds forold appliances, tires, car batteries,household garbage, agrochemicalcontainers, and dead animals.
Runoff, spills, or pesticides andfertilizers from lawns and farms can leachthrough the many spaces in the rock,unfiltered by the soil, enter thegroundwater system, and lead into watersources. Thousands of residents in ourregion get their water from home wells;and hundreds of new wells and septicsystems are installed here each year.Problems already have occurred. Residentsof Frederick County recall when one smalltown’s entire water system had to be shutdown for nine months, after a brokensewage line sent polluted water directlyinto the karst aquifer that supplied thetown’s water system.
Drinking water sources “werepolluted almost as soon as the leak was
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Figure 2
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MYTHS & FACTS ABOUT KARST AND SINKHOLES
MYTH: Putting things down a sinkhole won’tbother anyone. “Out of sight, out of mind.”
FACT: Contrary to the “out of sight, out of mind” approach, we shouldconsider sinkholes in terms of Karst’s ‘Reverse’ Law of Gravity: “Whatgoes down, eventually returns.”
MYTH: Seal or cover the sinkhole — say, with dirt,rocks, or asphalt — and it will go away.
FACT: Covering or “plugging” the sinkhole, without paying attention tothe subsequent movement of water, can give a false sense of security.
MYTH: If you leave a sinkhole alone, it willeventually take care of itself.
FACT: Sinkholes are a natural phenomenon, but we can’t always ignorethem — especially in populated areas. Nothing is simple. We have to examinesinkholes and, on a case by case basis, determine what should be done.
MYTH: All sinkholes imply natural void spaces or caves.
FACT: Actually, every depression in the ground — or even a hole — isn’tnecessarily a sinkhole. Such a hole could be caused by excavation for utilities,an old trash dump, or an abandoned well. It could be a “pseudo-sinkhole.” Howdo the experts assess such ‘artificial sinks?’ For starters, they examine a hole’s:1) shape; 2) location; and 3) land use history. They also consult geologic orsoils maps to see if limestones, dolostones, or marble exist in the area. (See the online Geologic Maps Series at www.mgs.md.gov/)Consider the shape of a depression or hole. Is it open or closed? Round orrectangular? Genuine sinkholes often start as depressions and open as funnel-shaped pits, depending on terrain. A closed, rectangular depression may suggesta collapsed trench or buried object, like an old brush pile or settling trash dump.What about location? What do you know of the history of the site? Does itsuggest a refuse pit, abandoned well or cistern, a submerged tank, or a utilitytrench? In some western counties, terrain is shaped by collapsed mine tunnels.One often brings questions like these to the examination of ground depressionsand apparent sinkholes.
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discovered,” one soil conservationistobserved.
Surface runoff carrying contaminantscan also pose danger to undergroundbiological life. Cave-dwelling organismsthrive in underground cracks andcrevices, in relatively dry environmentsand underwater. Understanding theseorganisms and their habitats requires thatwe learn more about karst and preventsurface contamination where we can.
PROBLEM: RUNOFF
Runoff refers to the water from rainor melted snow that does not infiltratethe soil but flows over the land surfaceas drainage. This is the water that flows,for example, from streets and parkinglots. Such water may be directed toconstructed ponds or other stormwatermanagement structures or, untreated,through storm drains into rivers andstreams.
Runoff can carry motor oil,antifreeze, salt, sand, litter, pet waste,fertilizer, yard and garden debris, andconsumer chemicals that have beendumped on the ground. In one study, bythe Environmental Protection Agency(EPA), some of the most toxic samplesof runoff were collected from residentialroofs, carrying such pollutants as birddroppings, roofing-material chemicals,and heavy metals leached from gutters.
In karst areas, sinkholes act verymuch like storm drains, carrying runoffinto fissures and caves, ultimatelydischarging into rivers, streams, lakes —or into wells, springs and other localsources of drinking water.
Studies show that sinkholedevelopment can be reduced bydispersing water runoff, allowing it toinfiltrate the ground over a wide area, asopposed to concentrating it in ditchesand swales. Developers attend to thespecial needs of karst areas, for example,
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by designing and constructing drivewaysand parking lots which disperse, ratherthan concentrate, rainwater runoff. Thisallows the water that would otherwise bedirected into drainage ditches andculverts to be dispersed around theperimeter of the paved area.
Some county officials in Maryland’skarst areas have considered specialkarst-sensitive water-managementpractices and specifications. Suchpolicies have been passed by localgovernments in other states.
County and local governments in otherstates have legislated special water-management practices for industrial orcommercial sites located in karst areas.
What You Can Do:• Never dump anything onto a
parking lot, into a storm drain, or down a sinkhole.
• Divert water run-off away from sinkholes.
• Recycle motor oil at a local gas station or recycling center.
• Use fertilizers wisely. Have soils tested to determine proper amounts.
• Keep pesticide use to a minimum. Use least-toxic alternatives.
• Maintain vegetation on steep slopes to keep soil in place.
• Compost yard and garden debris.• Do not overfill car radiators and
fix leaks.• Move down spouts from roof
gutters so water discharges onto grassy areas, away from your foundation and septic system. This allows runoff to filter into
the soil, where harmful pollutantsare broken down by soil organisms.
• Sinkholes that receive runoff should be remediated as soon as possible.
• Find and use the best practices for dispersed stormwater management in karst areas.
SEPTIC SYSTEMS AND KARST
To most of us, septic systems arehappily “out-of-sight” and “out-of-mind.” Proper operation andmaintenance of septic systems areimportant, however, to make sure theywork well and last longer.
When a septic system fails,inadequately treated sewage can reachthe groundwater, raising the risk ofserious diseases including dysentery,hepatitis, and typhoid fever. Nitrate andphosphate from domestic wastewater cancause excessive algae growth in springsand streams and impair aquatic life.Nitrate is also the cause ofmethemoglobinemia, or “blue babysyndrome,” a condition that prevents thenormal absorption of oxygen in theblood of infants.
In karst areas, according to the EPAand other researchers, failing septicsystems are a major source ofgroundwater pollution. Many of thesefailures are attributed to the presence ofkarst bedrock, old systems with outdateddesigns, and poor system maintenance.Many times septic system failures in
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karst areas are not noticeable on thesurface. The effluent “short circuits” orbypasses natural soil filtration, andenters the groundwater system. Thepartially treated or untreated dischargecan then spread throughout the aquifer.
What You Can Do:• Plant nothing but grass near
your septic system. Roots fromshrubs and trees can damage thetank and lines. Roots can alsobecome conduits for partiallytreated sewage. To protect tankconnections and distributionlines, prevent vehicles fromdriving or parking on any part ofyour system.
• Divert other water sources, suchas roof and street runoff, awayfrom your septic field. Excesssurface water can result insubsidence and septic systemfailure.
• Consider alternative, comparably
priced low-pressure dosingsystems that: 1) increase thecontact time between wastewaterand soils; 2) equalize thedispersion of waste waterthroughout the drain field (for lesschanneling), or 3) otherwisemaximize the natural absorptionand filtration properties of the soil.
• Work with the local healthdepartment and extensionservices to select the best systemfor your site. Contact healthofficials if you believe you have amalfunctioning system.
PROTECTING WELLWATER
Many rural home owners don’t thinkabout the source of their groundwater,believing it to be protected from surfaceactivity. In karst country, however, wellscan draw from groundwater pollution thatoriginates on one’s own property, on
Compaction grout is sometimes used to fill large karst cavities under roads and highways.Compaction grout is an extremely stiff grout composed of sand, fly ash, and cement.
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surrounding land, or miles away. In karstareas, the direction of surface runoff(down-slope) may be different than thedirection of underground karst drainage.Household wells and springs can becontaminated by common and seeminglyharmless activities occurring in anydirection, so everyone must be cautiousabout such activities as boarding orpasturing livestock; over-applyingpesticides, herbicides, or fertilizers; storinghome heating oil or gasoline; vehiclemaintenance; and on-site sewage disposal.
The best way to protect yourhousehold groundwater supply is tobecome “proactive,” beforecontamination happens, as opposed to“reactive,” when it’s too late. Proper
well siting is essential to keepingpolluted surface water out of the aquifer,and to avoid drilling into void spaces.(Local cavers and water managementdistricts sometimes develop maps thatcan assist in locating your well awayfrom subsurface cave passages.) Isolatethe well as much as possible, siting it atleast 100 feet away from barns, feedlots, livestock pens, sinkholes, dumps,septic systems, fuel tanks and otherpotential sources of contamination.
Landscape so that standing waterdoesn’t accumulate near the well, andfence any livestock out of the spring orwell-head area. Wells should be lined or“cased” with welded lengths of steelpipe, grouted into place. The top of the
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well should be surrounded by a concretepad and tightly capped or sealed.
Become familiar with the geologyand hydrology of your watershed. Workdiligently with neighbors to clean updumps, and limit potentially pollutingactivities in key water source areas.
What You Can Do:Homeowners and prospective home
buyers should be aware of “bestpractices” and local requirements forwell drilling and testing. Detectinggroundwater contamination requiresregular testing. Some countiesrecommend that wells be tested forbacteria and nitrates and other suspectedcompounds at least annually; others
recommend every six months. For those living in karst areas, it’s a
good idea to keep a record of tests as a“background” for evaluating any futurepollution. The record should also includethe dates that muddiness or low water levelproblems occur, as well as the existingclimate conditions when these events occur.
Test your water any time you noticeunusual odors, color, or cloudiness, or ifyou note an interrupted supply such aspumping air or sediment. Contact thecounty health department’s water qualitydivision for information on which testsmight be appropriate. Ask whether or notthe department performs such tests, orrequest a list of Maryland-certified water-testing laboratories serving your area.
SINKHOLES AND ZOIS
Under a 1991 Amendment to Maryland’s Surface Mining Law, theMaryland Department of the Environment (MDE) is required to establish anddefine Zones of Influence (ZOIs) around limestone and marble quarries inBaltimore, Carroll, Frederick, and Washington counties.
Limestone mining operations are required to repair a sinkhole within aZOI if MDE determines that the sinkhole resulted from quarry dewatering.Extraction companies also are required to replace a water supply that failsdue to declining water levels caused by a quarry’s water-pumping operation.If the sinkhole damage cannot be restored to its pre-subsidence condition,the quarry owner must pay monetary compensation to the affected propertyowner(s). MDE investigates complaints of sinkhole or water-supply failurewithin a Zone of Influence.
A quarry’s ZOI is based upon local topography, watersheds, geologicand hydrologic factors. When establishing Zones of Influence, MDEconducts field investigations and evaluates any available information suchas groundwater studies and well-monitoring data.
Anyone wishing to report complaint of a sinkhole or water-supply failureshould contact MDE’s Mining Program at (410) 537-3557. Those purchasinghomes within limestone (karst) terrains should inquire about limestonemining. MDE should be contacted to acquire ZOI maps.
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There are right and wrong ways todeal with a sinkhole. When a sinkholeopens, it cannot simply be “plugged” bypiling in various amounts of rock, dirt,or other debris. If a collapsed sinkholepresents a danger to health, safety, or tostructures, it should be stabilized in away that restores drainage patterns butinsures structural integrity; otherwise thesinkhole could return or “find” a newlocation.
In repairing sinkholes, planners andcrews draw upon a variety of potentialresponses, and tailor the remediation tofit specific site conditions. While no siteis the same, sinkhole repairs shouldalways pay as much attention tomaintaining water quality (hydrogeology)as to structural challenges. Repairtechniques include reverse-grade fill,building berms, and grouting. It’s best tocontact a geologist or engineerexperienced in sinkhole repair beforeattempting to backfill or “seal” asinkhole. The Natural ResourcesConservation Service has standards andspecifications for sinkhole remediation.
Septic systems, feed lots, animalwaste lagoons, and stormwater basinsshould not be located near known orsuspected sinkholes or caves.Appropriate methods should be used tominimize any unnatural or flooddrainage entering the sinkhole, and toprevent any and all runoff from bacteria-contaminated areas from entering.Similarly, one should refrain fromapplying fertilizer, pesticides, or other
chemicals within at least 100 feet of anactive sinkhole. One should always beaware of any sinkholes on your property,and share that information withcontractors, county health officials, andothers. The right approach to repairingsinkhole damage changes according tothe hole’s size and location. The goodnews: help and expertise are available,from informal consulting by localauthorities to professional excavationand engineering services.
If you purchase property where trashhas already been dumped into asinkhole, clean it out and restorevegetation to improve water quality.Check with your local NaturalResources Conservation Service(NRCS), Soil Conservation District,utility district, state conservation agency,or US Fish and Wildlife Service office.Volunteer labor and equipment also canbe a big help. Contact local cave clubsor the county recycling officer forsupport. (See Resource List on Page19).
Insurance coverage is available forgeologic hazards, although it varies fromstate to state. Collapses that occur near ahouse or other structures should beinspected by an engineer who isknowledgeable about karst problems.New homes and structures in karst areasshould be built with the help of ageotechnical engineer.
DEALING WITH PROBLEM-CAUSING SINKHOLES
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AGRICULTURE ONKARST
The region’s karst limestone rock hashelped nurture some of the bestagricultural soils in the mid-Atlanticregion. Farmers have long been familiarwith sinkholes and the implications fortheir lives and work. Good observers ofthe land can spot the early warning signsof sinkhole development, and take quickaction to stop soil erosion around one.
Farmers may be largely concernedabout the sinkhole that opens up anddamages farm equipment, but pollutionof groundwater from livestock waste,fertilizers, and pesticides can also be amajor problem. Farmers and soilconservationists have developedconservation and environmental farmingpractices that protect the groundwater inkarst terrain. Farmers who are interestedin learning more about cropmanagement and conservation practicesin karst areas may contact the WesternMaryland RC&D, local Soil
Conservation Districts, or the NaturalResources Conservation Service (NRCS)of the U.S. Department of Agriculture.Soil Conservation Districts can providespecific ideas on drainage diversiondesigns, filter strips, fencing, and basins.Maryland SCDs also provide othertechniques to reduce the impacts oferosion, sedimentation, manure, andagricultural chemicals on springs,streams, wells, marshes, lakes, andponds.
Public programs aimed at limitingagricultural runoff help farmers keeplivestock away from eroding streambanks, unprotected stream crossing,subsiding sinkholes, sinking streams,and natural waterways. (See “MACS andBMPs,” on this page.) CountlessMaryland farmers have contributed tohigher water quality by limitingovergrazing and restricting theirlivestock’s access to streams, conservingvaluable soil fertility while minimizingthe amount of sediment and nutrientsentering the watershed.
MACS & BMPs
The Maryland Agricultural Water Quality Cost-Share (MACS) Programfunds construction of eligible Best Management Practices (BMPs) to protectwater quality. Animal waste storage facilities, grassed waterways, springdevelopments, buffers, and cover crops are among the BMPs currentlyeligible for funding. Newer BMPs include stream protection practices,conservation cover, and nutrient management services. MACS pays up to87.5 percent of the cost for installing eligible BMPs. Repairing a sinkholethat is draining surface water into a clean groundwater source may beeligible for MACS funding. Consult local NRCS and county Soil ConservationDistrict offices for more information about MACS.
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What You Can Do:• Avoid structures that concentrate
water flow, especially into areasthat are not accustomed to theincrease. Soil-lined diversionditches often collapse whenstormwater erodes through tocaves and underground cavities.
• Leave a wide natural buffer oftrees and under-story vegetationaround sinkholes and caves whenclearing land, harvesting timber,or disturbing ground in thedrainage area.
• Never dump trash, dead animals,or debris into sinkholes. This isillegal in most areas because itcan directly and rapidly funnelleachate to springs and wells.
• Divert the flow of run-off awayfrom sinkholes.
• Keep cattle fenced away from thearea around a sinkhole.
What To Do If You Suspect a Sinkhole
The following are some steps to follow if you suspect sinkholeactivity:
STEP 1Is the sinkhole located in or adjacent to a karst area? At least two resourcescan be contacted to help make this determination:1) The Maryland Geological Survey’s online Geologic Maps Series atwww.mgs.md.gov/ helps determine the presence of karst-prone limestones,dolostones, or marble; or 2) Consult local soil maps to identify areas wheresoils originate from or overlie limestone and other material with some
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potential for developing sinkholes. Soil survey maps and interpretive information are accessible through local Soil Conservation Districts or byvisiting www.sawgal.umd.edu/nrcsweb/Maryland/index.htm. [The 2002Frederick County Soil Survey contains a soil interpretation table outliningthe relative potential for sinkhole formation by soil series.]
If the sinkhole is not within or near a karst area, subsidence may be due toconditions caused by past human practices (i.e. old foundations, abandonedwells, buried debris, etc.).
STEP 2If a sinkhole is within a mile of a quarry operation, it may fall within theZone of Influence (ZOI), established by the Maryland Department of theEnvironment. [See page 13.] If it affects a Maryland state road, contact theState Highways Administration Engineers Office at 301-791-4790.
STEP 3If the sinkhole is not within a ZOI, the following local agencies should becontacted:
Baltimore CountyDepartment of Environmental Protection and Resource Management willinspect and determine appropriate steps for all sinkholes. (Voice: 410-887-7428)
Carroll CountySinkholes Associated with Agricultural Uses:Carroll County Soil Conservation District will inspect and determine if asinkhole is eligible for repair/mitigation cost share. (Voice: 410-848-8200)
Other sinkholes:Carroll County Bureau of Resource ManagementProgram developed to map locations, provide technical assistance withrepairs, and education on sinkhole occurrences. (Voice: 410-386-2639)
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Frederick CountySinkhole affecting county roads and rights-of-way:Frederick County Office of Highway Operations.(Voice: 301-694-1564)Sinkhole on Private Property:Frederick County Soil Conservation District.(Voice: 301-695-2803)
Washington CountySinkholes on County Roads or Highways:Washington County Highway Department.(Voice: 240-313-2720); Washington County Engineering Department provides technicalassistance/advice on sinkhole related problems on construction sites orexisting dwellings:(Voice: 240-313-2400); For general assistance or advice or to report sinkholes affecting streets inHagerstown city limits, contact the City Engineers Office (Voice: 301-790-3200); The County Soil Conservation District inspects and determines whether asinkhole is eligible for MACs. (See page 15.) (Voice: 301-797-6821).
Most local jurisdictions do not have programs or funding for sinkhole repairon residential or commercial/industrial property. The level of technicalassistance available depends on the jurisdiction, but might include anapproximation of the sinkhole’s cause, potential for future occurrences orgrowth, proper repair techniques, and best-management practices to helpavoid future occurrences.
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Baltimore County Questions about and reports of
sinkholes are generally referred to theDepartment of Environmental Protectionand Resource Management (DEPRM),Department for Public Works. Thedepartment generally sends an inspectorto examine the sinkhole and determine“next steps.” Voice: 410-887-7428.
Carroll CountyThe Carroll County Planning
Department offers technical assistance tolandowners and others. The office hasdocumented approximately 500sinkholes in the county— logging theirlocation, size and treatment history. Theoffice has given technical assistance toland owners on some sites, whileconducting repair on those that endangerroads, sidewalks, or municipal andcounty wells. [Questions about privatewell and septic systems should bedirected to the Environmental HealthDivision of the County HealthDepartment (410-876-1884).]Department of Planning, Carroll CountyOffice Building, Room 204, 225 N.Center Street, Westminster, Maryland21157. Voice: 410-386-2145.
Frederick County Questions about and reports of
sinkholes on private properties aregenerally referred to the Soil ConservationDistrict and/or Natural ResourcesConservation Service, 92 Thomas Johnson
Dr., Suite 230, Frederick, MD 21702-4300; Voice: 301-695-2803.
Washington CountyIf the sinkhole affects a county road
or highway, residents are asked to callthe Highways Department, at 240-313-2720. The department will takeinformation about the sinkhole and senda supervisor to examine the site.
If the sinkhole affects a public projectduring construction, the problem goes tothe project manager. If the problem occurson a residential project or an existingdwelling, it is referred to a field inspectorof the Engineering Department (Voice:240/313-2400). Although unable to givematerial assistance, field engineers aregenerally able to advise residents on theirkarst-related problems.
NATURAL RESOURCESCONSERVATION SERVICE(NRCS) FIELD OFFICES AND COUNTY SOILCONSERVATION DISTRICTS
Allegany County11602 Bedford Road, NECumberland, MD 21502Voice: 301-777-1494
Baltimore CountyAgricultural Building9831 Van Buren LaneCockeysville, MD 21030Voice: 410-666-1188
LOCAL RESOURCES
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Carroll County1004 Littlestown PikeSuite B-2Westminster, MD 21157-300Voice: 410-848-6696
Frederick County92 Thomas Johnson Dr.Suite 230Frederick, MD 21702-4300Voice: 301-695-2803
Washington County1260 Maryland Ave., Suite 101Hagerstown, MD 21740-7204Voice: 301-797-6820
When called upon by landowners inany county, NRCS staff are able to offerlimited technical assistance. TheMaryland office of NRCS has drafted anapproved standard method (No. 725) for“treating sinkhole areas to reducecontamination of groundwater resources.”[The updated soil surveys for Frederickand Washington counties provide a soil-interpretation rating for potential sinkholeoccurrence by soil series.]
The Maryland Geological Survey(MGS) offers geological information
obtained through applied geologicalstudies and mapping. MGS developsinformation on Maryland’s earthresources, and nurtures the wise andorderly development of these resourcesthrough geologic and hydrologic studies,assessments, and evaluations. (TheMaryland Geological Survey observesits 110th anniversary in 2006.)
Private consultants can be found inarea phone listings. When using anengineering firm, ask about geo-technicaltraining, experience, and references.
Western Maryland ResourceConservation & Development Council(RC&D) — The Western MarylandRC&D is a private, nonprofitorganization promoting environmentalsustainability, education, naturalresources stewardship, rural viability,and economic opportunities in Allegany,Carroll, Frederick, Garrett, andWashington counties. The RC&DCouncil manages natural resourcesprojects in partnership with privatefoundations, businesses, non-profitorganizations, and government agencies.The RC&D maintains a library ofinformation about karst regions.
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NATIONAL LINKS
National Speleological SocietyThe National Speleological Society
2813 Cave AvenueHuntsville, AL 35810-4413Voice: 256-852-1300www.caves.org
US Geological Surveywater.usgs.gov/ogw/karst/index.htm
INFORMATION ON DISPOSINGOF HOUSEHOLD HAZARDOUS WASTE
Carroll County Recycling Operations225 North Center StreetWestminster, MD 21157
Voice: 410-386-2633
Frederick County Dept. of Waste Management/RecyclingURL: www.co.frederick.md.us/Recycling/
Voice: 301-694-1848
Washington County Solid Waste DepartmentRecycling: 240-313-2796
URL: www.washco-md.net/public_works/solid_waste/solidw.htm
Baltimore City Bureau of Solid WasteURL: www.baltimorecity.gov/government/dpw/waste.html
Baltimore County Department of Environmental Protection andResource Management (DEPRM)
Voice: 410-887-4066URL: www.co.ba.md.us/Agencies/environment/hazwaste.html
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WESTERN MARYLAND RC&D18450 Showalter Road, Suite 111 • Hagerstown, MD 21742-1383
Voice: (301) 733-2973 • Fax: (301) 733-7643E-mail: [email protected]: users.erols.com/wmarylandrcd/
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