Code of Colorado Regulations
400 - Department of Natural Resources
402 - Division of Water Resources
2 CCR 402-2 - RULES AND REGULATIONS FOR WATER WELL CONSTRUCTION, PUMP INSTALLATION, CISTERN INSTALLATION, AND MONITORING AND OBSERVATION HOLE/WELL CONSTRUCTION
14 - MINIMUM CONSTRUCTION STANDARDS FOR MONITORING AND OBSERVATION WELLS, MONITORING AND OBSERVATION HOLES, AND TEST HOLES
Universal Citation: 2 CO Code Regs 402-2 ยง 14
Current through Register Vol. 47, No. 17, September 10, 2024
Basis and Purpose: The statutory authority for this Rule is found in sections 37-91-101(1); 37-91-104(1)(c), (j) & (k); 37-91-106(4). The purpose of this Rule is to establish minimum construction standards for certain types of holes and wells that may be constructed by authorized individuals who are not specifically licensed by the Board.
14.1 General - Monitoring and observation wells and monitoring and observation holes are primarily used for observing groundwater levels and flow conditions, obtaining samples for determining groundwater quality, and for evaluating hydraulic properties of water-bearing strata. Test holes are primarily used for conducting geotechnical or geological investigations. See Section 37-91-102 (10.5) and (15.7), C.R.S., and Rule 5.2 for definitions and authorized uses for each type of structure.
14.1.1 If the holes do not
penetrate a confining layer, monitoring and observation holes or wells, and
test holes may be constructed by an authorized individual (see Rule 5.2.3 and
Rule 9), a licensed well construction contractor, or a private driller (see
Section 37-91-102(12),
C.R.S). Rules 6, 7, 9, 14 and 17 for licensing, notification and reporting
requirements (summarized in Table 1). Monitoring and observation holes or wells
and test holes that penetrate a confining layer between two distinct aquifers
may not be constructed by an authorized individual. All holes or wells that
penetrate a confining layer between two distinct aquifers must be drilled by a
licensed contractor and must comply with the standards of Rule 10.
14.1.2 All monitoring and observation holes
or wells and test holes must comply with the construction standards and
plugging, sealing, and abandonment standards specified in these Rules. Notice
and reporting requirements for compliance with this Rule 14 are stated in Rule
9.2 . The person authorized to construct and to plug, seal, and abandon
monitoring and observation holes and test holes must ensure that the proper
notice has been provided to the State Engineer pursuant to Rule 6.3, keep
accurate records of work performed, and submit the required reports to the
State Engineer (see Rule 17).
14.1.3 Prior to starting construction, all
persons authorized to construct monitoring and observation holes or wells or
test holes must investigate and become familiar with the geology and
hydrogeology of the area, potential aquifers, confining layers, anticipated
water quality problems, and known contaminated water-bearing zones which may be
encountered in the area of the proposed drilling activity.
14.1.4 When hazardous contaminants are known
or suspected to be encountered during construction, the authorized individual,
licensed contractor, or private driller is responsible for ensuring that all
personnel on site are adequately trained and that proper safety equipment is
provided to handle and contain those substances.
14.1.5 Drill cuttings and wastewater from
monitoring and observation wells/holes or test holes in areas of known or
suspected contamination must be managed in accordance with all applicable
federal, state, and local regulations or laws.
14.1.6 All wells and boreholes, when
unattended, must be securely sealed, capped, or covered to ensure protection of
the groundwater resource. During construction, it is the responsibility of the
person constructing the hole or well to ensure the borehole is securely covered
when unattended. Upon completion of construction, the hole or well must be
securely sealed or capped by the person responsible for construction.
Thereafter, it is the responsibility of the hole or well owner to ensure that
the hole or well remains securely sealed or capped.
14.1.7 Authorized individuals and well
construction or pump installation contractors who encounter a monitoring and
observation hole or well that appears not to meet the standards of these Rules,
or a damaged monitoring and observation hole or well, or an open and unattended
hole or well, must notify the Board of Examiners in writing of the location of
such holes or wells.
14.2 Monitoring and Observation Holes/Wells - Monitoring and observation holes constructed pursuant to notice as provided in Rule 6.3 and in accordance with the standards of this Rule 14 may only be used for those purposes described in Section 37-91-102 (10.5) and may not be converted to production wells for beneficial use. A monitoring and observation well must be permitted by the State Engineer, and may be used for the purposes described in Rule 5.2.31 and section 37-91-102 (10.5), C.R.S. A monitoring and observation hole may only be converted to a monitoring and observation well, recovery well for remediation of the aquifer, or a dewatering system for dewatering the aquifer, if such conversion is approved and permitted by the State Engineer.
14.2.1
Monitoring and Observation Hole - Prior to the start of
construction of any monitoring and observation hole (see Rule
5.2.30 for definition), the State Engineer must be notified pursuant to Rule
6.3 . The authorized individual, owner of the monitoring and observation hole,
or the owner's technical representative (i.e. consultant) is responsible for
providing the required notice. The monitoring and observation hole must be
constructed within ninety (90) days of giving such notice.
14.2.1.1 Construction of a monitoring and
observation hole must be completed within 72 hours after drilling the borehole,
unless the contractor or authorized individual has obtained approval from the
Board of Examiners for an extension of time to complete the
construction.
14.2.1.2 A monitoring
and observation hole that will exist for more than eighteen (18) months must be
permitted by the State Engineer as a monitoring and observation well.
14.2.1.3 The individual who submitted the
notice of intent for the monitoring and observation hole must notify the owner,
in writing, that a permit from the State Engineer must be obtained for the
monitoring and observation hole or that the hole must be properly plugged,
sealed, and abandoned within eighteen (18) months of the date the monitoring
and observation hole is constructed.
14.2.2
Monitoring and Observation
Well - All monitoring and observation wells must be permitted by the
State Engineer. The well owner or the well owner's authorized agent is
responsible for obtaining the Monitoring/Observation Well Permit, and may
obtain the Monitoring/Observation Well Permit from the State Engineer prior to
the construction of a monitoring and observation well, if the owner expects or
knows that the structure will exist for more than eighteen (18) months or
expects that the structure will be converted to a production well.
14.2.2.1 A monitoring well constructed after
obtaining the proper monitoring well permit from the State Engineer may only be
converted to a production well if a permit to use groundwater has been obtained
from the State Engineer and if the well was constructed by a licensed well
construction contractor in accordance with the well construction standards of
Rule 10.
14.2.2.2 A monitoring and
observation well that was originally constructed under a notice of intent as a
monitoring and observation hole may not be converted
to a production well.
14.2.2.3 All
monitoring and observation wells must be plugged, sealed, and abandoned upon
completion of the intended purposes of the well.
14.2.3 A copy of the applicable notice or
permit obtained from the State Engineer must be available at the construction
site at all times during construction of a monitoring and observation hole or
well. Monitoring and observation wells or holes may not be constructed without
proper notice, a permit, or emergency approval from the State
Engineer.
14.2.4
Location - Monitoring and observation holes or wells must be
located to allow access for maintenance, modification, repair, and plugging,
sealing and abandonment. When selecting the location, the contractor or
authorized individual must consider the topography, drainage and other on-site
conditions in order to promote groundwater protection and public
safety.
14.2.5
Damaged Holes
or Wells - The owner of the monitoring and observation hole or well is
responsible for the repair, replacement or plugging, sealing and abandonment of
any damaged monitoring and observation hole or well.
14.2.6 The responsible individual (see Rule
9.1) must submit all work reports within sixty (60) days after completion of
construction of the monitoring and observation well or hole in accordance with
Rule 17.
14.3 Monitoring and Observation Hole/Well Construction Standards - The construction of monitoring and observation wells or holes must be generally consistent with the examples of acceptable construction shown on Figure 7, unless the monitoring and observation well will be converted to a production well (see Rule 14.2.2).
14.3.1
Locking
Cover - The top of a monitoring and observation hole or well must be
protected by a locking cover or equivalent level of protection to prevent
unauthorized access.
14.3.2
Casing Cap - The top of a monitoring and observation hole or well
must be fitted with a cap or "sanitary seal" to prevent surface water,
pollutants, or contaminants from entering the hole or well. Openings or
passages for water level measurement, venting, pump power cables, discharge
tubing, and other access must prevent entry of surface water, pollutants, and
contaminants.
14.3.3
Wellhead
Completion - The top of the well casing must terminate at least one (1)
foot above ground surface, except where site conditions, such as vehicular
traffic, will not allow. PVC casing must not be exposed above ground surface.
Steel surface casing or well vaults are acceptable wellhead completion
designs.
14.3.4
Bases for
Monitoring and Observation Wells - A concrete base or pad must be
constructed around the top of the casing of a monitoring and observation well
at ground surface and contact the annular seal, unless the top of the casing is
below ground surface as provided by Rule 14.3.5 . The base must be at least 4
inches thick and must slope to drain away from the well casing. The base must
extend at least two feet laterally in all directions from the outside of the
well boring.
14.3.4.1 The base must be free of
cracks, voids, and other significant defects likely to prevent water tightness.
Contacts between the base and the annular seal, and the base and the well
casing, must be watertight and must not cause the failure of the well casing or
annular seal.
14.3.4.2 Where
cement-based annular sealing material is used, the concrete base must be poured
before the annular seal has set.
14.3.5
Vaults - The top of the
well or hole casing may be below ground surface if justified by traffic or
other critical considerations. A structurally-sound watertight vault or
equivalent structure must be installed to house the top of the annular seal to
at least ground surface. The top of the annular seal must not be more than 4
feet below ground surface.
14.3.5.1 The vault
must contact the annular seal in a manner to form a watertight and
structurally-sound connection. Placement of the vault must not cause the
failure of the well casing or annular seal.
14.3.5.2 Where cement-based annular seal
materials are used, the vault must be set into or contact the annular seal
material before it sets. If bentonite-based sealing material is used for the
annular seal, the vault must be set into the bentonite before the bentonite is
fully hydrated.
14.3.5.3
Cement-based sealing material must be placed between the outer wall of the
vault and the excavation into which it is placed to form a structurally sound
foundation for the vault, and to seal the space between the vault and
excavation.
14.3.5.4 Sealing
material surrounding a vault must extend from the top of the annular seal to
ground surface. If cement-based sealing material is used for both the annular
seal and the space between the excavation and vault, the sealing material must
be placed in a continuous pour. In other words, cement-based sealing material
must be placed between the vault and excavation and contact the cement-based
annular seal before the annular seal has set.
14.3.5.5 The vault cover or lid must be
watertight but must allow the venting of gases. The lid must be fitted with a
security device to prevent unauthorized access. The lid must be clearly and
permanently marked "MONITORING WELL". The vault and its lid must be strong
enough to support vehicular traffic where such traffic might occur.
14.3.5.6 The top of the vault must be set at
or above grade so drainage is away from the vault. The top of the well casing
contained within the vault must be covered in accordance with requirements of
Rules 14.3.1 and 14.3.2 so that water, contaminants, or pollutants will not
enter the well casing.
14.3.6
Protection from Vehicles and
Livestock - Protective steel posts, or the equivalent, must be installed
around a monitoring and observation hole or well casing where it terminates
above ground surface in areas of vehicular traffic. The posts must be highly
visible and must protect the hole or well from vehicular impact. At locations
where livestock have access to the hole or well site, monitoring and
observation holes and wells must be enclosed by fencing or structure adequate
to prevent livestock from contacting and damaging the hole or well.
FIGURE 7
MONITORING AND OBSERVATION HOLES/WELLS
Figure 7. Schematic diagrams of typical monitoring and observation hole/well designs.
14.4 Installation of Pumping Equipment - Aquifer testing and/or test pumping of any monitoring and observation hole or well must not exceed a cumulative total of two hundred (200) hours unless prior written approval for additional testing is obtained from the State Engineer. The well owner or his or her agent are responsible for obtaining appropriate permits and complying with all rules and regulations pertaining to the discharge of all fluids produced during the testing.
14.4.1 Test pumping equipment may be
installed in a monitoring and observation hole or well by an authorized
individual, well construction or pump installation contractor, or well owner.
The person installing the equipment must notify the State Engineer within 72
hours of when pumping equipment is installed in a monitoring and observation
hole or well if such equipment is to remain in the hole/well for a period
exceeding 72 hours.
14.4.2 The
installation of test pumping equipment in a monitoring and observation hole or
well must comply with the applicable provisions of Rule 13 and Rule
15.
14.4.3 Water level data and/or
water sample analyses obtained from a monitoring and observation hole or well
must be submitted to the State Engineer upon request.
14.4.4 Monitoring and observation holes and
wells, dewatering wells, and recovery wells are exempt from the disinfection
standards of Rule 15 if disinfection conflicts with the purpose of the
well.
14.5 Test Holes - Test holes are defined at section 37-91-102 (15.7), C.R.S., in Rule 5.2.51, and Table 1 and are administered in accordance with the requirements of the State Engineer.
14.5.1 Test holes that
penetrate through a confining layer between two distinct aquifers
a. Require a notice of intent be submitted to
the State Engineer prior to construction
b. Require a lithologic log and construction
report be submitted to the State Engineer
14.5.2 Test holes that do not penetrate
through a confining layer
a. Do not require a
notice of intent be submitted to the State Engineer prior to construction
b. Do not require a lithologic log
and construction report be submitted to the State Engineer
14.5.3 When unattended, test holes must be
securely sealed, capped, or covered.
14.5.4 Test holes must be plugged, sealed,
and abandoned upon completion of the intended purposes of the test
hole.
Disclaimer: These regulations may not be the most recent version. Colorado may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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