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Best Management Practices
for
Groundwater Protection
A Guide for
Local Officials and
Public Water
Suppliers
Maine Department of Human Services
Drinking Water Program
December, 2005
Prepared by: Modified
from a report by:
B. Potential
threats to groundwater
D. Wellhead
protection in Maine
E. Local
action in groundwater protection
II. PRINciples of Groundwater Contamination
A. Piling
of materials or waste can be a problem..
B. Heavier
than water solvents can cause long lasting contamination
C. Metals
are controlled by pH (acidity), and Eh (oxidation/reduction potential)
E. Organic
chemicals are recalcitrant
G. Chemicals
in common use are common groundwater contaminants
I. We
can make contamination a thing of the past
J. Planning
is the key to the future
III. Principles of land use regulation for Groundwater protection
D. Enforce
proper maintenance and proper practice.
E. Know
when there is a problem
F. Remember
to consider potential future uses
IV. Facilities and activities that require attention
V. best management practiceS (BMPs)
C. CHEMICAL
SPREADING OR SPRAYING
E. STORM
WATER AND PARKING LOTS
G. RESIDENTIAL
ACTIVITIES AND HOME OCCUPATIONS
Groundwater
Protection Best Management Practices
A
Guide for Local Officials and Public Water Suppliers
This manual is intended for
the use of local officials, public water suppliers and landowners in
The purpose of groundwater
protection is to avoid contamination from inappropriate land uses located close
to public supply wells. The result of
sound protection is that water pumped from public supply wells will meet all
drinking water standards, now and in the future.
The protection of public and
private drinking water supplies involves the following activities:
1. Delineation
of an area around a well that defines the area from which groundwater flows
towards the well. The total area is
known as a wellhead protection area (WHPA), and is commonly divided into 2 or 3
zones that provide different levels of protection. Qualified professionals employed by either
the Water System or the State Drinking Water Program usually do this work.
2. Preparing
an Inventory of existing facilities and activities within that area. This work is usually completed by the Water
System, and reviewed by the Drinking Water Program.
3. Management
to avoid threats to groundwater quality by remediating and controlling
existing sources of contamination, properly designing new facilities, and limiting
certain activities within the WHPA. This
work is done by property owners and applicants for new developments, guided by
State or local regulations. This last
activity is what this manual is intended to support.
What is a “Potential threat to Groundwater”? Any land use, whether industrial, commercial,
agricultural or domestic that uses or produces any substance that could find
its way through the soil to the water table below is a potential threat to
groundwater. Once these substances (either
chemical or biological) have reached the water table and contaminated the water
directly below the source, they can travel with the flow of groundwater as it
makes its way to a nearby stream or lake, or to the next well. Aside from the environmental concern, the
threat to human society comes when we want to use that contaminated groundwater,
which may have implications for public health and safety.
The potential threat of any land use is site-specific. It will depend on the chemical’s solubility
and persistence, its toxicity, the volume spilled or leached into the ground,
the filtering capability of the local soil, and the proximity of wells.
This manual is about choosing appropriate sites for a
particular land use, and managing those uses with the best practice. It is intended to reduce the likelihood of accidental
release of hazardous materials that may threaten drinking water resources
around the wellheads of public supply wells.
However, much of this best management practice could be taken to apply
to land uses in general, such that all groundwater is protected, which is our
ultimate goal in
Wellhead Protection is a practical method of ensuring the
quality and quantity of water pumped from a public supply well is neither
degraded nor diminished by unwise land use decisions. Wellhead protection is based upon five basic
premises:
1. When
water is drawn from a well, other water is drawn from the surrounding aquifer
towards the well to replace it. The
volume of aquifer from which water is drawn will depend upon the unique
characteristics of the aquifer, like its shape, and whether it’s a sand and
gravel aquifer or a fractured bedrock aquifer.
These and other unique characteristics can be determined by
hydrogeologic studies. The volume of
aquifer involved will also depend upon the pumping rate of the well and amount
of recharge to the aquifer. In simple
terms, given some geologic information and a few assumptions, one can calculate
and draw on a map, a “Zone of Contribution” around the well.
2. Some
water entering the aquifer is drawn from adjacent surface water bodies such as
brooks, rivers and lakes.
3. Precipitation
falling on land is the ultimate source for all water pumped from wells.
4. Rainwater
(and snow melt), percolating through soils can wash contaminants into the
aquifer (sometimes via adjacent surface water bodies). Such contaminants may pass through the
aquifer into the well.
5. By
controlling land uses in the Zone of Contribution to the well and in the
watershed of surface water bodies contributing to the well, we can protect the
quality of well water.
The State of
Zone 1. Zone 1 includes land areas immediately
surrounding the well. These areas must
receive the greatest levels of protection, namely ownership or control by the
public water supplier or community.
Zone 2. Zone 2 surrounds Zone 1, and should receive
some measure of protection by land use controls imposed by local officials
working cooperatively with the public water supplier and landowner.
Zone 3. Zone 3 includes a larger land area that may
include the total zone of contribution to a well, or it may include the
watershed upgradient of the well. Land
use controls are usually no more stringent than current environmental
protection regulations, though it is still worthwhile to identify Zone 3 for
educational purposes and planning.
The State Drinking Water
Program currently has a three-tiered scheme for classifying wellhead protection
areas around public supply wells. The
three tiers of wellhead protection are as follows:
1. Public
supply wells in sand and gravel aquifers (gravel-packed wells with screens)
must be protected by zones defined by “time of groundwater travel”. The process involves computer simulation of
groundwater flow towards the well. The
boundary of Zone 1 is set at a groundwater travel time of 200 days, which is
based upon the expected life of viruses in groundwater. The Zone 2 boundary is set at 2,500 days (7
years), which is the time it might take to identify, study and remediate a
chemical spill. Zone 3 may be designated
as the contributing watershed to the well in question.
2. Public
supply wells with higher yields, and obtaining water from bedrock aquifers, are
protected by three zones designated by a professional based upon relative
confidence that the contributing area is properly identified. Zone 1 is defined with the highest
confidence, Zone 2 somewhat less. Zone 3
may be designated as the contributing watershed to the well in question.
3. Relatively
small wells (e.g. those serving schools and restaurants) identify Zone 1 using
a calculated fixed radius around the well that is proportionate in area to the
number of people the well serves, and thus to the average yield of the well. Zone 2 is designated as a circle with a
radius of 2,500 feet. There is no
designated Zone 3.
In
With few exceptions, land use control and regulation in
Maine generally lies in the hands of the landowner and the municipality (local
Planning Board and Code Enforcement Officer (CEO) Large scale projects may be regulated by the
Department of Environmental Protection, but for the most part, towns,
landowners, and public water suppliers must work together to ensure protection
of drinking water supplies.
One of the most effective ways to
accomplish this is to develop and adopt a local wellhead protection or drinking
water protection ordinance, or include wellhead/drinking water protection
provisions in the local land use ordinance(s).
This Guide, the Best Management Practices (BMPs) for Groundwater
Protection was developed specifically to help local communities protect their
drinking water supplies. These BMPs can
be used as guidance and education for landowners and developers. They can be used to help in reviewing
developments, as conditions of approval, as performance standards, or advice
for landowners who may not come under official municipal review.
1. Scan
the introductory material to this manual (Sections II and III). Even if you read the headlines, you will find
it educational.
2. Become
familiar with the Public Water Well that is the subject of your deliberations,
including its location and specifics of the delineation of the Wellhead
Protection Area around it.
3. Work
through the List of Potential Contamination Sources (Section IV, Table 1) until
you find the one or ones that most closely fit the facility with which you are
concerned.
4. Find
the major activities that are associated with that potential contaminant source
(Table 1, the letter codes in this table refer to the subsections of Section V
of this manual).
5. Read
subsection Descriptions, and Major Potential Threats.
6. Consider
which BMPs should apply.
7. Apply
them cautiously. Facilities may change
in use over time.
The following general principles may help in understanding
how groundwater contamination occurs and how it can be avoided.
This applies to all kinds of materials and wastes. For instance, wood wastes, when left in small
quantities the woods, do not adversely affect groundwater quality. However, when stored in large quantities,
like at a lumberyard or in a stump dump, they can cause groundwater beneath and
downgradient of the pile to become contaminated. The same can be said of other organic
materials, such as stored potato culls or certain types of residuals.
Unlined landfills are known
to leak hazardous materials as surface water percolates through the pile. The contaminated water, known as leachate, can cause long
lasting contamination. For example, chlorinated solvents,
such as perchloroethene (PCE, the solvent used in dry-cleaning),
trichloroethene (TCE, a common degreasing solvent) and methylene chloride (a
common paint remover) are all heavier than water. If spilled on the ground, they tend to sink
through soils to the water table. From
here, they may sink to any depth within an aquifer. The three substances mentioned above biodegrade
slowly, sometimes producing daughter chemicals that are more toxic than the
original compound. Spills are very
difficult or near impossible to remediate.
Even salt can cause a problem in fractured bedrock aquifers. Salt water is denser than freshwater and
sinks to the deepest cracks in the bedrock.
In dry seasons or heavy use, these deepest cracks are tapped, and salt
contaminated water may be discovered.
Oxidation and reduction potential
(“redox”), and pH to some extent, is linked to the amount of available oxygen
in a particular area. Highly reduced
conditions can free toxic metal molecules from their chemical bonds and allow
them to move freely in ionic form in groundwater. For example, wetland soils usually are oxygen
depleted and the redox potential is high.
In wells receiving groundwater recharge from nearby wetlands, the concentration
of free iron and manganese in the water is usually high because of they have
been freed from other chemical bonds.
The same kind of situation can arise around plumes of contaminated
groundwater, such as those originating from a landfill or a gasoline spill.
Pathogens such as bacteria and viruses occur in domestic and
municipal wastewater manure, and even runoff from lawns. Pathogens are rare as groundwater
contaminants except when leachfields are too close to a well, and/or the well
is not properly constructed. Bacteria
have a tendency to attach onto soil particles, and are not common groundwater
contaminants. However, they can migrate
rapidly to groundwater through shallow bedrock fractures or coarse gravel
soils, and can also get into wells through insecure casings. Little is known about viruses as groundwater
contaminants, except that they remain viable up to 150 days.
While many natural organic chemicals decompose easily, there
are many synthetic organic chemicals that do not. PCE and TCE as well as methylene chloride
were mentioned above. In addition two
other common synthetic organic chemicals are the gasoline additives MTBE
(methyltertiarybutyl ethanol), ETBE (ethyltertiarybutyl ether) or TBA
(tertiarybutyl alcohol), which are water soluble and can travel great distances
from the site of a spill.
Unlike surface water resources, dilution is not the solution
to pollution. Groundwater contamination does
not spread away from a spill site in a fan like manner, rather most “plumes” of
groundwater contamination are pencil shaped.
They are generally not wider than the source of the spill and
contamination is more linear. Thus
contaminants do not disperse, but remain concentrated in a defined area.
Some of the most common groundwater contaminants include
salt (from deicing of roads in winter, or from sea water intrusion in coastal
areas), nitrate (from over-use of fertilizers, or from septic system leachate),
gasoline (from spills), and trihalomethanes (from use of chlorine products and
disposal in wastewater in septic systems).
Every public supply well is located in a unique geologic
setting. Gravel packed wells are found in
extensive and thick deposits of sand and gravel. These may or may not be covered by layers of
clay that prevent recharge (and contamination) from entering the aquifer in the
area around the well. Bedrock wells tap
into fractures beneath the surface, which collect large volumes of groundwater
both from surrounding fractures and from soils above. All wells pump groundwater that is a
renewable resource replenished by rain and snowfall that trickles down through
soils. It is the purpose of these BMPs
to ensure that this renewable resource is kept as clean as possible.
With education and regulatory/financial incentives we have
come a long way to making groundwater contamination a thing of the past. For instance we have replaced tens of
thousands of underground gasoline storage tanks with technology that is
designed not to leak; we have replaced the worst degreasing chemicals with
citrus-based substitutes; and we now line landfills and cover sand/salt piles.
Land use planning is key to the protection of groundwater
resources. The location and design of
new development within defined Wellhead Protection Areas can only help protect
the resource for the future.
Because
of the differences in town political structure, land use regulation, review and
enforcement capacity, it is difficult to make a ‘one size fits all’ set of BMPs
appropriate to all situations in all
One of the most difficult problems
faced by water districts and towns is determining the level of acceptable
risk. Prohibition of all uses and
activities will provide the most protection while careless siting of unsafe
uses and activities would provide the least.
The acceptable middle ground between these two options will vary from
town to town.
The simplest way to protect the water
supply is to keep potential contamination sources out of the wellhead
protection area. Political realities may
make this a difficult option to adopt in some towns, but many towns consider
the safeguard to the town investment in the water supply and ease of
administration and enforcement of ‘just saying no’ a good trade-off.
If a potential contamination
source must be sited in a wellhead protection area, limiting the size of
development is the next step. If
properly constructed and maintained, a small used car lot may present a smaller
risk than a large gravel lot or a truck terminal. Keeping risks small may also mean reducing
the scale of development. For example, one
fuel storage tank may only be required at a used car lot instead of three.
Often the water supplier and the
town don’t even know when and where a potential contamination source is being
used or stored. The location and
composition of every potential contaminant source within the wellhead
protection area should be known and emergency contingency plans for how to deal
with any spills, accidents, and fires are in place. Landowners and/or operators should be aware
of their potential to negatively affect the water supply. Complete inventories should include a ground
survey and a search through state and local records.
Businesses or landowners using,
storing or creating potential contaminants should be using proper practices to
protect the water supply. Multi-barrier
approaches are better than single barriers, so that if there is an accident, like
a problem with a holding tank or containment structure, there is a back up to
protect the water supply. Proper
maintenance of structures and equipment will reduce the chance of accidents.
Require those located in the wellhead protection area to
promptly notify the town and water supplier when there are spills or accidents
involving potential contamination sources.
Buildings may outlast zoning in a
town, but with proper care the groundwater will outlast both. It is tempting to allow structures or uses in
the wellhead protection area because they seem innocent enough when they are
proposed. But remember to consider
future changes. A 3-bay garage for the
hobby woodworker may become perfect place for an auto body shop if zoning
changes.
These basic principles will help
to set your goals for wellhead protection.
The basic question in setting goals however is one of risk management or
“How much risk are you willing to live with and for what reasons?” Goals should be clear so that they are easily
communicated to the public.
The State Drinking Water Program has a list of Potential
Contamination Sources that public water suppliers should consider when
developing a wellhead/sourcewater protection plan under the State’s
Wellhead/Source Water Protection Program.
This Guide uses the same list. Because
any one facility may pose a threat to groundwater in several ways, we have
cross-referenced this list to the particular activities that pose a
threat to groundwater quality.
Table 1 identifies a variety of activities that pose a
potential risk of contamination. Major
activities are cross-referenced to Section V of this manual. Major threats, relative risks and
recommendations for prohibition are listed in the table as well.
Table 1:
|
Potential
Contaminant Sources |
Major
Activities See
section V for BMPs |
Major
Threats to Groundwater Quality |
Relative
Risk |
Recommendations |
Applicable
State Regulations |
Comments |
||
|
Zone
1 |
Zone
2 |
Agency |
Regulatory
Chapter |
|||||
|
Agricultural chemical spreading or spraying |
A, C |
fertilizers, pesticides |
Medium |
No |
PB/PWS |
DoA (BPC) |
CMR 01-026 Chapter CMR 01-026 Chapter 41 |
Affects Phase II/V Waivers |
|
Agricultural chemical storage |
A |
fertilizers, pesticides |
Medium |
No |
PB/PWS |
|
|
|
|
Bulk grain storage |
A |
pesticides |
Medium |
No |
PB/PWS |
|
|
|
|
Chemically fertilized agricultural field |
C |
fertilizers, pesticides |
Medium |
No |
PB/PWS |
|
|
Affects Phase II/V Waivers |
|
Golf course |
A,C |
fertilizers, pesticides |
Medium |
No |
PB/PWS |
|
|
Affects Phase II/V Waivers |
|
Herbicide sales or applicator |
A, C |
Herbicides |
High |
No |
PB/PWS |
DoA (BPC) |
CMR 01-026 Chapter 41 |
|
|
Nursery or garden shop |
A, C |
Fertilizers, pesticides |
Medium |
No |
PB/PWS |
|
|
|
|
Pesticide sales or applicator |
A, C |
Pesticides |
High |
No |
PB/PWS |
DoA (BPC) |
CMR 01-026 Chapter 41 |
|
|
High voltage transmission lines |
C |
Herbicides |
Low |
No |
PB/PWS |
|
|
|
|
Above ground bulk oil storage tank |
A |
Fuel oil |
High |
No |
PB/PWS |
Fire Marshall |
|
|
|
Underground oil storage tank |
A |
Gasoline, diesel |
High |
No |
No |
DEP |
CMR 06-096 Chapter 691 |
|
|
Airport fueling area |
A |
Jet fuel, gasoline |
High |
No |
No |
DEP |
CMR 06-096 Chapter 691 |
|
|
Airport maintenance |
A, B |
Gasoline, diesel, solvents |
High |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
Limit size of facility in WHPA |
|
Auto chemical supply wholesaler |
A |
Petroleum chemicals, solvents |
Medium |
No |
PB/PWS |
|
|
Limit size of facility in WHPA |
|
Auto repair |
B |
Gasoline, solvents |
High |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
Limit size of facility in WHPA |
|
Potential
Contaminant Sources |
Major
Activities See
section V for BMPs |
Major
Threats to Groundwater Quality |
Relative
Risk |
Recommendation |
Applicable
State Regulations |
Comment |
||
|
Zone
1 |
Zone
2 |
Agency |
Regulatory
Chapter |
|||||
|
|
|
|
|
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
Limit size of facility in WHPA |
|
Concrete, asphalt, tar, coal company |
A |
PAH compounds |
Medium |
No |
PB/PWS |
DEP |
|
Limit size of facility in WHPA |
|
Dry cleaner |
B |
Perchlorethlyene (PCE) |
High |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
|
|
Furniture stripper |
B |
Methylene chloride |
High |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
|
|
Gas station, service station |
A, B |
Gasoline, diesel |
High |
No |
No |
DEP |
CMR 06-096 Chapter 691 |
Not allowed in WHPA by law |
|
Junk or salvage yard |
A, B |
Gasoline, solvents |
Medium |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 400 |
|
|
Machine shop |
B |
Petroleum, solvents |
High |
No |
PB/PWS |
|
CMR 06-096 Chapter 850 |
Small storage only |
|
Oil pipeline |
A, B |
Gasoline, fuel oil |
Hi/med |
No |
PB/PWS |
DEP |
|
Special design precautions |
|
Painters, finishers |
B |
Paints and solvents |
Medium |
No |
No |
|
CMR 06-096 Chapter 850 |
Small storage only |
|
Parking lot |
E ,F |
Petroleum, metals, PAH |
Medium |
No |
PB/PWS |
DEP |
|
Low use parking areas only |
|
Photo processor |
B |
Silver |
Medium |
No |
PB/PWS |
|
CMR 06-096 Chapter 850 |
Permit on-site rebuilding |
|
Printer |
B |
Solvents |
Medium |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
Only on sewer |
|
Sand and gravel mining, other mining |
J |
Gasoline diesel, other oils |
Medium |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 378 |
Allow no fueling on site |
|
Small engine repair shop |
B |
Gasoline, solvents |
Hi/med |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
Small storage and waste only |
|
Snow dump (large commercial or municipal) |
E, F |
Petroleum, metals, PAH, nutrients |
Medium |
No |
No |
DEP |
|
|
|
Stormwater impoundment or run-off area |
F |
Petroleum, metals, PAH, nutrients |
Medium |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 500 |
Limit size of facility in WHPA |
|
Truck terminal |
F, I |
Petroleum, metals, PAH, nutrients |
High |
No |
PB/PWS |
|
|
Limit size of facility in WHPA |
|
Animal burial (large scale) |
H |
Bacteria, nutrients |
Medium |
No |
PB/PWS |
|
|
Limit size of facility in WHPA |
|
Animal grazing |
C |
Bacteria, nitrates |
Low |
Yes |
PB/PWS |
|
|
Limit animal density |
|
Barnyard |
C |
Bacteria, nitrates |
Medium |
No |
PB/PWS |
|
|
|
|
Manure pile |
A |
Bacteria, nitrates |
High |
No |
PB/PWS |
|
|
Limit size of facility in WHPA |
|
Potential
Contaminant Sources |
Major
Activities See
section V for BMPs |
Major
Threats to Groundwater Quality |
Relative
Risk |
Recommendations |
Applicable
State Regulations |
Comments |
||
|
Zone
1 |
Zone
2 |
Agency |
Regulatory
Chapter |
|||||
|
Manure spreading |
C |
Bacteria, nitrates |
Medium |
No |
PB/PWS |
DoA |
Guidance |
Require nutrient management plan |
|
Meat packer, slaughter house |
D |
Bacteria, nitrates |
Medium |
No |
No |
|
|
|
|
Municipal wastewater treatment plant |
D |
Bacteria, nutrients |
Medium |
No |
PB/PWS |
DEP |
Guidance |
|
|
Abandoned well |
L |
|
Medium |
No |
No |
DHS |
CMR 10-144 Chapter 232 |
|
|
Boat builders, refinisher, maintenance |
B |
Paint chips, new paint |
High |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
|
|
Chemical reclamation |
C |
Solvents |
High |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
|
|
Food processor |
D |
Bacteria, nutrients |
Low/med |
No |
No |
|
|
|
|
Graveyard/cemetery |
H |
Bacteria, nutrients |
Low |
No |
PB/PWS |
|
|
|
|
Heat treater, smelter, annealer, descaler, |
A, B |
Paint, solvents |
Med |
No |
No |
DEP |
CMR 06-096 Chapter 850 |
|
|
Incinerator |
D |
Solvents |
Hi/med |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter, CMR 06-096 Chapter 403 |
|
|
Industrial discharge |
D |
All |
High |
No |
No |
DEP |
CMR 06-096 Chapter 850 |
|
|
Industrial manufacture |
A, B, C, D, E, I, K, L |
All |
Hi/med |
No |
No |
DEP |
CMR 06-096 Chapter 850 |
Limit size of facility in WHPA |
|
Industrial waste disposal |
B, C, D |
All |
High |
No |
No |
DEP |
CMR 06-096 Chapter 400, CMR 06-096 Chapter 850 |
|
|
Landfill, dump, transfer station |
D |
All |
High/low |
No |
No |
DEP |
CMR 06-096 Chapter 400 |
|
|
Metal plating |
C |
Metals |
High |
No |
No |
DEP |
CMR 06-096 Chapter 850 |
|
|
Military facility |
A, B, C, D, E, F, I, K, L |
All |
High |
No |
No |
DEP |
CMR 06-096 Chapter 850 |
|
|
Monitoring well |
L |
|
Low |
Yes |
Yes |
DEP, DHS |
CMR 06-096 Chapter 405, CMR 10-144 Chapter 232 |
|
|
Railroad yard or line |
A, B |
All |
Medium |
No |
PB/PWS |
|
|
|
|
Recycling or processing center (other than
beverages) |
A, C, D, E, K |
Solvents |
Medium |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
Limit size of facility in WHPA |
|
Research laboratory |
A, B, D |
Solvents, radioactive |
Medium |
No |
PB/PWS |
|
|
Limit size of facility in WHPA |
|
Rust proofer |
A, B, D |
Fuel oil |
Medium |
No |
PB/PWS |
DEP |
CMR 06-096 Chapter 850 |
|
|
Potential
Contaminant Sources |
Major
Activities See
section V for BMPs |
Major
Threats to Groundwater Quality |
Relative
Risk |
Recommendations
|
Applicable
State Regulations |
Comments |
||
|
Zone
1 |
Zone
2 |
Agency |
Regulatory
Chapter |
|||||
|
Salt pile or sand and salt pile (uncovered) |
A |
Salt |
High |
No |
PB/PWS |
DEP |
|
Must be covered |
|
Septic system |
D |
Bacteria, nutrients, household chemicals |
High |
No |
PB/PWS |
DHS |
CMR 01-026 Chapter 41 |
Limit size of facility in WHPA |
|
Septic
waste (“septage”) disposal |
D |
Bacteria,
nutrients, household chemicals |
|
|
|
DEP |
CMR
06-096 Chapter 420 |
|
|
Beauty parlor |
B, D |
Solvents |
Medium |
No |
PB/PWS |
DHS |
CMR 01-026 Chapter 41 |
Only on sewer |
|
Car wash |
B, D |
Gasoline |
Low |
No |
PB/PWS |
DHS |
CMR 01-026 Chapter 41 |
Only on sewer |
|
Laundromat |
D |
|
Medium |
No |
PB/PWS |
DHS |
CMR 01-026 Chapter 41 |
Only on sewer |
|
Medical, dental, veterinarian office |
D |
Mercury, medical wastes |
Medium |
No |
PB/PWS |
DHS |
CMR 01-026 Chapter 41 |
Only on sewer |
|
Mortuary/funeral parlor |
H |
Formaldehyde |
Medium |
No |
PB/PWS |
|
|
Only on sewer |
|
Multi-unit housing |
D, G |
Herbicides, chemical spraying |
Medium |
No |
PB/PWS |
|
|
Limit size of facility in WHPA |
|
Single-family housing |
D, G |
Herbicides, chemical spraying |
Medium |
No |
PB/PWS |
|
|
Limit size of facility in WHPA |
|
Sewer lines |
D |
Bacteria, nutrients |
Medium |
No |
PB/PWS |
DEP |
Guidance |
Only on sewer |
|
Sludge disposal |
C, D |
Bacterial, nutrients |
Medium |
No |
No |
DEP |
CMR 06-096 Chapters 4000-419 |
|
|
Agronomic Sludge spreading |
C, D |
Bacterial, nutrients |
Medium |
No |
PB/PWS |
DEP |
CMR 06-096 Chapters 4000-419 |
|
|
Wastewater impoundment area |
D |
Bacteria, nutrients |
High |
No |
No |
DHS |
|
|
|
Wastewater treatment plant, discharge |
D |
Bacteria, nutrients |
Medium |
No |
PB/PWS |
DEP |
|
|
|
Wood preserver |
B |
Chromium, copper, arsenic |
High |
No |
No |
DEP |
CMR 06-096 Chapter 850 |
|
|
Hoop houses and greenhouses |
B, C |
Pesticides, chemicals spraying |
Medium |
No |
PB/PWS |
|
|
|
|
Home heating oil tanks |
B |
Fuel oil, kerosene |
High |
No |
PB/PWS |
OSFB |
NFP Code 31 |
|
|
Log yards and lumber mills |
|
Wood waste piles |
High |
No |
No |
DEP |
|
High iron, manganese and chemical oxygen demand |
Notes:
PB
= Planning Board (including ongoing monitoring by the Code Enforcement Officer
OSFB
= Oil and Solid Fuel Board (in the Maine Department of Professional and Financial
Regulation)
PWS
= Public Water System (owner or Utility Trustee)
NFP
= National Fire Protection (not a State regulation)
DoA
= Maine Department of Agriculture
DHS
= Maine Department of Health and Human Services
BPC
= Board of Pesticide Control (in the Maine Department of Agriculture)
DEP
= Maine Department of Environmental Protection
The following BMPs can be associated with a wide cross
section of uses and activities. For
example, chemical storage occurs at automobile repair shops, beauty salons and
the water district, to name a few. Since
these BMPs can be incorporated in many different agricultural, commercial,
industrial, retail and residential uses, we recommend that each particular use
in the WHPA be scrutinized for the following particular practices.
Definition: Chemical
storage includes storage in tanks (above and underground), and in drums or
other containers. It can also include
storage of solid chemicals in bags, or in bulk (in piles or silos).
The principal chemicals of concern regarding groundwater
contamination include petroleum products, solvents, agricultural chemicals,
manure and road salt. Stored waste
chemicals are also a concern.
S
Petroleum products include gasoline and
jet fuels that have low viscosity and soluble components (such as MTBE and
benzene), as well as home heating oil.
S
Solvents include a variety of degreasers
and cleaners such as trichloroethene (TCE), perchloroethene (PCE) and methylene
chloride, all of which are used widely in industrial and commercial facilities.
S
Agricultural chemicals include
nutrients/fertilizers, and various pesticides (including fungicides, herbicides
and insecticides).
S
Waste chemicals can include unused
paints, paint scrapings, spent solvents, and diluted wash water.
Federal and State regulations make a distinction between
Hazardous Materials and Hazardous Wastes.
The former can include virgin materials, while the latter results from a
process, including spillage.
S
Leakage of liquid chemicals from tanks and
drums. Note that underground tanks are
more liable to produce undetected leaks because they cannot be inspected while
in operation.
S
Leaching of solid chemicals in bulk, if material
is exposed to precipitation.
S
Massive leaching with water during fire-fighting
emergencies.
S
Spills during transport and delivery.
Zoning or land use recommendation:
Zone 1: Prohibit, except for uses of Public Water
System
Zone 2: Use BMPs.
Limit size as much as possible.
1. Underground
storage tanks are prohibited by State law in Wellhead Protection Areas.
2. Store
all chemicals under cover, and on impervious working surfaces, without floor
drains. Design storage space so that failures, emergencies, extreme storm
events or routine site clearing will not cause material or wash water to run on
bare ground.
3. All
piping shall be designed to prevent line breakage by collision.
4. All
containers and piping shall be secure and resistant to corrosion.
5. All
containers shall be clearly labeled with name of chemical, and date of purchase
(or generation of waste).
6. Adequate
spill clean up materials must be kept on hand at the facility. Spills must be cleaned up promptly, and
spilled materials disposed of properly.
7. “Pre-plans”
for firefighting must be prepared bearing in mind the possibility that
chemicals could cause groundwater contamination if washed out of a burning
building by water. Foam materials and
spray plans should be included in the plan, appropriate to the materials and
quantities stored in the facility.
8. Determine
if chemicals being stored are “hazardous” by characteristic, or are a listed
hazardous waste by state and federal agencies.
Information on hazardous materials may be obtained from the Maine DEP. If materials are either, ensure that DEP’s
hazardous waste regulations are being followed.
In any case follow the BMPs above.
9. In
addition to the standards set by the Oil and Solid Fuel Board, new home heating
oil tanks should be a UL-80 listed tank with a bottom outlet, the tank ends
should be welded to the body using a lap joint and not a crimp connection. Also, any outdoor home heating fuel oil tank
should be sited either under the roof eave or away from falling snow or ice,
should have protective filter cover, and be painted white to avoid condensation
within the tank.
10. Manure,
ash, and liming agents used for agricultural purposes must also be stored under
cover.
Special Provision for large
facilities and storage units (> 275 gals or liquid material or → 275 lbs
of dry material)
1. Provide
secondary containment to include impervious holding of fluids of at least 20%
of the volume of storage of all liquid chemicals, and 110% of the volume of the
largest storage container, by permanent dikes or other means.
2. Tanks
for liquid storage shall be equipped with automatic shutoffs and high level
alarms. Personnel shall be trained to
respond to shutoffs and alarms.
3. Prepare
a Spill Prevention, Containment and Countermeasure Plan (SPCC) for submittal to
the CEO, Fire Department and Water District.
Information on developing an SPCC plan may be obtained from the Maine
DEP. This plan shall include provisions
to prevent and catch spills during loading and transfer activities. This SPCC plan shall be reviewed and updated
annually.
4. Inspect
all storage areas at least weekly, and maintain an inventory and tracking
system.
Special Provisions for chemical
storage in relation to vehicle use
1.
When draining oils or fluids from vehicles,
precautionary measures, such as portable drip pans, must be taken to ensure
that no spills occur.
2.
All fuel oil, waste oil, lubricants, antifreeze or
other potential contaminants must have secondary containment equal to 110% of
the liquid volume stored.
Definition: Chemical
use includes but is not limited to: combustion, degreasing and other cleaning,
mixing and dilution with other chemicals or water, catalytic reactions, all
with or without the production of a waste material. Some waste materials are recycled on a
limited scale during the process. Types of chemicals include all those listed
above under chemical storage, except for agricultural chemicals, manure and
road salt.
Major potential problems:
Through spillage or disposal, chemical waste materials can reach
soils and move through them to groundwater.
Spillage or disposal can be intentional or accidental. Many chemicals have been known to contaminate
groundwater to above drinking water standards.
Zoning or land use recommendation:
Zone 1: Prohibit, except for uses of Public Water
System
Zone 2: Use BMPs.
Limit amount of use as much as possible.
1. Require
the use non-hazardous alternatives to hazardous chemicals whenever
possible. If hazardous chemicals must be
used, provide justification for why they cannot be replaced by non-hazardous
chemicals.
2. Design
chemical feed lines and temporary storage containers to prevent spillage by
collision and corrosion.
3. Clearly
label all storage vessels and chemical feed lines with chemical name.
4. Check
for spillage and leaks at least weekly.
Leaking containers must be removed or placed in secure containers that
are larger than the leaking container.
5. Prepare
a SPCC Plan.. This plan shall include
provisions for cleaning up small spills and containing large spills in an
emergency. Keep emergency cleanup
materials on hand. Information on
developing an SPCC plan may be obtained from the Maine DEP.
6. All
spills must be promptly reported to the Maine DEP, the Town (CEO and Fire
Department) and the Water System.
Special provisions for chemical use
in relation to vehicles
1.
Vehicle washing must occur on a concrete pad with
sealed sumps to capture wash water.
2.
Refueling of vehicles must occur on a concrete pad with
sealed sumps to capture spills.
Definition: Some
chemicals, including most agricultural and silvicultural chemicals, are
deliberately spread or sprayed over the ground surface, or on plants. “Agricultural” applies in this case to
commercial operations greater than 2 acres, hoop/greenhouses, or nursery/garden
shops greater than 1,000 square feet.
Transportation and utility corridors are also included in this category.
Major potential problems: Some agricultural chemicals are very
soluble. If they are applied during a
seasonal period of groundwater recharge (principally during the rainy spring
season), much of the chemical applied will contaminate groundwater rather than
being agriculturally useful.
Zoning or land use recommendation:
Zone 1: Prohibit
Zone 2: Use BMPs. Limit amount spread or sprayed as much
as possible.
1. Pesticide
and herbicide application should be the option of last resort. Any activity requiring the use of herbicides
or pesticides should develop an Integrated Pest Management Plan that details
the conditions under which agricultural chemicals are to be used. All pesticides shall be applied in accordance
with label directions and the regulations of the Maine Board of Pesticides
Control.
2. Herbicides
and pesticides must be applied only by trained personnel, i.e. by certified
applicators, who must be informed regarding the delineated area of wellhead
protection.
3. All
agricultural fertilizers shall be applied in accordance with label directions,
and must be applied in accordance with an approved Nutrient Management Plan
4. Fertilizer
applications are to be tailored to the specific needs of the crop, as
determined by soil suitability analyses.
Use of slow-release fertilizers is preferred.
5. Irrigation
schedules shall be coordinated with pesticide and nutrient application to
minimize the possibility of leaching. Do
not apply to frozen ground, or immediately before storm events.
6. Notice
of intent to apply agricultural chemicals shall be given to the CEO and public
water supplier prior to application.
1. A
Nutrient Management Plan must be provided for all agricultural activities
within the WHPA.
2. Only
Class “A” composted residuals may be
used within WHPA. These residuals must
have an approved Program License from the Maine Department of Environmental
Protection, and must be used in strict accordance with all license
provisions. Any non-composted residual
or a residual not meeting the Class “A” pathogen reduction standard should not
be spread within the WHPA. See Section
D.3 below for more information on residuals.
3. Manures
must be composted to Class "A" standards. Manure may be used within the WHPA, and must
be applied in accordance with the nutrient management plan.
4. Tailor
application of approved residuals and manures to the specific needs of the
crop, as determined by soil suitability analyses.
5. Residuals
and manures shall not be applied over very shallow soils (less than 1 foot) or
exposed bedrock.
6. Residuals
and manure shall not be applied on frozen ground, or immediately before storm
events.
Definition: Wastewater
results from the flushing of waste products in a water-soluble or water-based
form. It can include a wide variety of
different types of wastes. Solid Waste
includes solid material that is either incinerated or disposed of in
landfills.
Major potential problems:
Domestic and municipal wastewater
is high in organic matter in the process of decomposition. It is treated most commonly by aeration in a
lagoon, and/or by land disposal via a septic system leachfield
(drainfield). Soils are usually
excellent for removing very high concentrations of bacteria within a few hundred
feet from a septic system. However,
leachfields are common sources of nitrate-rich leachate in groundwater.
Some chemical wastes are
discharged improperly via septic system leachfields. Industrial wastewater disposal is regulated
by the state, and except for the state plumbing code, commercial, retail and
domestic wastewater disposal may not be regulated. Improper disposal of some chemicals may
result in groundwater contamination. The
most common such disposal is of chlorine products, which produce
trihalomethanes in groundwater.
Residuals are solid wastes
generated from municipal, commercial or industrial wastewater treatment plants
that have been tested and found to meet strict state and federal safety guidelines. They are mostly organic material, but may
contain elevated concentrations of metals or other chemicals. Due to their potential to impact ground and
surface waters if improperly handled, the use of these materials are strictly
regulated by the DEP.
Only composted
residuals meeting the Class “A” level of pathogen reduction should be used in
the WHPA. For more information on the
composting and pathogen reduction standards, contact the Maine DEP.
Municipal solid waste disposed of
in landfills produces a leachate that is very similar to domestic and municipal
wastewater in concentrations and components.
The leachate can contain chemical components that result in groundwater
contamination downgradient of landfills.
Liner systems for land fills can reduce the risk of contamination, but
they are not completely secure.
Municipal incinerator ash commonly
has elevated concentrations of various trace metals, which could potentially be
mobilized through soils to groundwater below.
Wood
waste, though innocuous in the woods, can be the cause of groundwater
contamination beneath log storage yards and piles of wood waste (bark, slabs,
sawdust). Iron and manganese, chemical
oxygen demand and tannin/lignin are all elevated and can create a vile odor in
the water.
Other wastewater discharges, such
as direct discharge of floor drains can wash hazardous chemicals directly to
groundwater. State and Federal law
prohibits any direct discharge of wastewater at sites where there is a
significant potential for industrial, hazardous or toxic liquids – including
gasoline, oils or degreasers – to drip, be spilled or washed into the drains.
Zoning or land use recommendation:
Zone 1: Prohibit
Zone 2: Use BMPs.
1. Municipal
wastewater disposal facilities, chemical waste disposal sites of any kind,
spreading of biosolids and incinerator ash except Class "A" residuals
as described in Section C of this document, solid waste landfills, log storage
yards and lumber yards, and other direct discharges shall be prohibited in
WHPAs
2. Septic
systems and sewer pipes shall be prohibited in Zone 1 WHPAs (Zone 1 is 300 ft
in many cases).
3. Sewer
pipes shall preferably be relocated outside WHPAs. Alternatively, pipes may be lined internally
where buried within Zone 2 WHPAs.
Definition: Storm
water is derived from precipitation (rain or melted snow) that drains rapidly
from relatively impervious surfaces such as roofs and parking lots.
Major potential problems:
Impervious surfaces or grading of the land to accelerate drainage
prevents natural recharge of precipitation to groundwater. Even gravel driveways and lawns drain water
quickly. Storm water from “active areas”
such as frequently used parking lots may contain significant concentrations of
contaminants such as petroleum products, metals and salt. (By contrast, “inactive” impervious surfaces
such as roofs can produce useful, clean recharge water.)
Zoning or land use recommendation:
Zone 1: Prohibit parking areas, except for Public
Water System uses.
Zone 2: Use BMPs.
Limit amount of impervious area including but not limited to parking,
sidewalks, rooflines and as much as
possible.
1. Zone
1: The impervious area of any lot should
be limited to 10% or less of the lot to encourage natural recharge.
2. Zone
2: The impervious are of any lot should be limited to 15% or less of the lot to
encourage natural recharge.
3. Use
of vegetated buffers and pervious pavement options should take priority over
structural storm water control like detention ponds.
4. Storm
water should be diverted away from WHPAs if possible.
5. Infiltration
of stormwater from impervious areas greater than 20,000 square feet should be
prohibited. Any detention or retention
structures should be constructed in such a manner that excludes groundwater
interaction.
Definition: The one aspect of road maintenance that
causes significant groundwater contamination is winter de-icing with salt.
Major potential problems: Uncovered sand and salt
piles can leach almost half their salt into groundwater. The use of pure salt on highways has
increased the incidence of nearby domestic wells becoming contaminated.
Zoning or land use recommendation:
Zone 1: Minimize use of salt.
Zone 2: Use BMPs.
Limit size of pile as much as possible.
1.
Cover all sand and salt piles.
2.
Minimize use of salt in all cases.
Definition: Residential
activities include: production of septic wastes, use of gasoline or fuel oil,
automotive or similar shop work, lawn or garden care with fertilizers and
pesticides, and use and disposal of chemicals from home occupations such as
photographic studios, beauty salons, car washing activities, etc.
Major potential problems:
Most homes contain stores of small quantities of several hazardous
chemicals (gasoline, fuel oil, bleach, paint thinners, pesticides, drain
cleaners, etc.). Many homeowners are
unaware that disposal of small quantities of these chemicals through septic
systems or on the ground may cause significant groundwater contamination.
Zoning or land use recommendation:
Zone 1: Prohibit residential development, if
possible.
Zone 2: Use BMPs.
Limit residential development and/or type and scope of home businesses.
1. Residential
uses should be prohibited in Zone 1 if possible. If allowed they should be located on lots of
at least 5 [AW1][AW2]acres,
with a requirement that septic wastes are to be disposed of at least 300 feet
from the well and with at least 10 feet of soil cover, and a replacement
leachfield be designated with similar stipulations.
2. Residential
uses may be allowed in Zone 2, with net density of at least 2 acres/unit, with
a requirement that a replacement leachfield be designated on each lot.
3. Developers
of residential subdivisions within WHPAs shall complete a nitrate loading
study. Nitrate and nitrite
concentrations should not exceed 5 mg/L at the property line.
4. Residents
of properties located within Zone 2 WHPAs should be informed of the potential
for groundwater contamination from domestic use of various chemicals.
5. Home
occupations proposed for WHPAs shall come under Planning Board review for
consideration of how they may impact groundwater quality. No disposal of chemicals from home
occupations shall be allowed within WHPAs.
6. Vehicles
within Zone 1 WHPAs must be parked on impermeable surfaces.
7. Home
heating oil tanks shall be prohibited in Zone 1 WHPAs, and replaced with
alternative fuel or heating sources.
8. New
homes should be constructed without sumps that discharge to bare soil.
9. New
home and replacement home heating fuel oil tanks must meet the standards set by
the Oil and Solid Fuel Board, In
addition, new home or replacement heating oil tanks should be a UL-80 listed
tank with a bottom outlet, the tank ends should be welded to the body using a
lap joint and not a crimp connection.
Any outdoor home heating fuel oil tank should be sited either under the
roof eave or away from falling snow or ice, should have protective filter
cover, and be painted white to avoid condensation within the tank.
Any spills from residential activities should be reported to
the Public Water Supply and CEO.
Definition: Gravesites
include not only human cemeteries, but also mass graves for animals (with
>1000 lbs of carcass in one burial site).
Major potential problems:
Single burials are not a problem, however, mass graves can overload
the soils capacity to decay organic material and can cause significant
deterioration of groundwater quality.
Fortunately, composting of carcasses produces no leachate or groundwater
contamination. Also, large human
cemeteries are frequently well manicured with continual chemical spraying and
spreading. See Sections B and C
above.
Zoning or land use recommendation:
Zone 1: Prohibit
Zone 2: Use BMPs.
1. Cemeteries
should not be permitted in Zone 1, WHPAs.
2. Carcasses
should be composted rather than buried.
Definition: Firefighting
includes prevention as well as activities associated with emergency dowsing of
fires.
Major potential problems:
Water used to control fires at chemical storage sites can cause
widespread groundwater contamination because the water becomes contaminated
before leaving the site. In addition,
chemicals stored or in use at the location of the fire could potentially leak
and cause widespread groundwater contamination.
1. Prepare
“Pre-Plan” for fire prevention and fire suppression for all facilities within
WHPAs. These plans should be tailored to
the materials stored on site, and designed to limit groundwater contamination
in the event of fire. This emergency
contingency plan should be part of any SPCC plan developed under Section B and
C above.
2. Contingency
Plans and meetings with the local fire department should be required.
Definition: Mining
involves the removal of mineral materials from the earth. It can include excavation of sand and gravel,
removal of rock, or extraction of metallic ores.
Major potential problems:
Mining for metallic ores presents the greatest problem in regards to
water quality, with generation of leachate that is generally acid and with high
concentrations of metals. Mining for
rock or sand and gravel may, under some circumstances, cause unintended changes
in the flow of groundwater. Any mining
produces pits, which can be used for illegal dumping. Vehicles used for mining
may be the cause of spills. Rock
crushers use water that may wash pollutants into the groundwater.
Zoning or land use recommendation:
Zone 1: Prohibit
Zone 2: Use BMPs. Limit size as much as possible.
1.
No part of any extraction operation may be permitted
within 150 feet of any property or street line, except that drainage ways to
reduce run-off into or from the extraction area may be allowed up to 100 feet
from such line. No part of the extraction operation, including drainage and
runoff control features, may be permitted within 100 feet of the normal
high-water line of a water body or upland edge of a wetland. Natural vegetation
must be left and maintained on the undisturbed land. Excavation may not occur
below the level of the traveled surface of any street, road, or right-or-way
within 150 feet of that street, road, or right-or-way, except that excavation
below the traveled surface level may occur within 150 feet of a private road or
right-of-way with the written permission of the owner of that road or
right-of-way. A natural buffer strip at least 150 feet wide must be maintained
between any excavation and a property boundary, including a street
right-of-way. This distance may be reduced to not less than 10 feet with the
written permission of the affected abutting property owner or owners, except
that the distance may not be reduced to less than 25 feet from the boundary of
a cemetery or burial ground. The distance between excavations owned by abutting
owners may be reduced to not less than 75 feet with the abutter's written
permission.
2.
Separation must be maintained between any excavation
and any public drinking water source as follows: (1) For systems serving a population of 500
persons or less, the minimum separation must be 300 feet; (2) For systems serving a population of 501
persons up to 1,000 persons, the separation must be 500 feet; (3) For systems serving a population of more
than 1,000 persons, the separation must be 1,000 feet; and (4) For any system
that holds a valid filtration waiver in accordance with the federal Safe
Drinking Water Act, the separation must be 1,000 feet
3.
If any standing water accumulates, the site must be
fenced in a manner adequate to keep out children. Measures must be taken to
prevent or stop the breeding of insects.
4.
No slopes steeper than 3 feet horizontal to 1 foot
vertical are permitted at any extraction site unless a fence at least 6 feet
high is erected to limit access to such locations.
5.
Before commencing removal of any earth materials, the
owner or operator of the extraction site must present evidence to the Planning
Board of adequate insurance against liability arising from the proposed
extraction operations, and such insurance must be maintained throughout the
period of operation.
6.
Any topsoil and subsoil suitable for purposes of
revegetation must, to the extent required for restoration, be stripped from the
location of extraction operations and stockpiled for use in restoring the
location after extraction operations have ceased. Such stockpiles must be
protected from erosion, according to the erosion prevention performance
standards of this section.
7.
Sediment must be trapped by diversions, silting basins,
terraces or other measures designed by a professional engineer.
8.
The sides and bottom of cuts, fills, channels, and
artificial water courses must be constructed and stabilized to prevent erosion
or failure.
9.
The hours of operation at any extraction site must be
limited as the Planning Board deems advisable to ensure operational
compatibility with nearby residences.
10. Excavation
may not extend below 5 feet above the seasonal high water table without the
submission of detailed findings of the depth of the water table. The Board may,
upon verified determination of the depth of the seasonal high water table,
permit excavation within 2 feet above the water table.
11. Loaded
vehicles must be suitably covered to prevent dust and contents from spilling or
blowing from the load, and all trucking routes and methods are subject to
approval by the Road Commissioner and the Planning Board. No mud, soil, sand,
or other materials may be allowed to accumulate on a public road from loading
or hauling vehicles.
12. All
access and or egress roads leading to or from the extraction site to public
roads must be treated with suitable materials to reduce dust and mud for a
distance of at least 100 feet from such public roads.
13. No
equipment debris, junk, or other material is permitted on an extraction site.
Any temporary shelters or buildings erected for such operations and equipment
used in connection therewith must be removed within 30 days following
completion of active extraction operations.
14. Within
6 months of the completion of extraction operations at any extraction site or
any one or more locations within any extraction site, ground levels and grades
must be established in accordance with the approved plans filed with the
Planning Board. These plans must provide for the following:
15. All
debris, stumps, boulders, and similar materials must be removed or disposed of
in an approved location or buried and covered with a minimum of two feet of
soil.
16. The
extent and type of fill must be appropriate to the use intended. The applicant
must specify the type and amount of fill to be used.
17. Storm
drainage and water courses must leave the location at the original natural
drainage points and in a manner such that the amount of drainage at any point
is not significantly increased.
18. At
least 4 inches of topsoil or loam must be retained or obtained to cover all
disturbed areas, which must be reseeded and property restored to a stable
condition adequate to meet the provisions of the "Erosion and Sediment
Control, Best Management Practices," published by the Maine Department of
Environmental Protection.
19. No
slope greater than 3 feet horizontal to 1 foot vertical is permitted.
20. Disused
gravel pits within the WHPA shall be reclaimed according to plans submitted to
the Municipality.
21. Gravel
mining activities in Wellhead Protection Areas must have emergency spill
response plans.
Definition: Fill
is contaminated if it has a non-natural odor, or is stained, or comes from a
known source of contamination, such as the site of an underground tank removal
project.
Major potential problems:
Contaminated fill can become the source for groundwater
contamination for long periods, as the contamination is leached out into the
subsurface.
1. Use
only inert material (loam, sand, gravel, clay, rocks, bricks or concrete).
2. Use
only clean fill (no non-natural odors, no staining, and not originating at a
known spill site).
3. Implement
erosion and sedimentation control measures.
Definition: Wells
are structures (usually vertical shafts) used to access groundwater for
extraction or monitoring purposes.
Major potential problems:
Wells provide a possible conduit for contaminants originating in
surface water or upper aquifers to migrate to groundwater below. Wells placed within the same Zone of
Groundwater Contribution will interfere with each other, causing a reduction in
the Safe Yield of both.
1. Wellheads
shall be designed such that surface water does not enter groundwater through
the borehole around the well casings.
2.
Wells that are no longer in service for extraction or
monitoring shall be abandoned in a manner appropriate to prevent the entry of
contaminants and mixing of separate subsurface water-bearing zones. This may involve the use of bentonite and/or
cement grout where a water-tight seal is deemed necessary.
3. High
yielding wells (for uses other than domestic purposes) will only be allowed in
the WHPA if a safe yield analysis, conducted by a Maine Certified Geologist,
can demonstrate that there is sufficient water for both the new well and the
public water source.