(A) Purpose. This section is intended to protect the public health, safety, and general welfare by protecting groundwater from pollution or depletion resulting from construction, reconstruction, repair, or abandonment of geothermal systems. An open loop geothermal system that penetrates and/or draws water from an aquifer can deplete or pollute groundwater. An improperly constructed or maintained closed loop geothermal system can also pollute the city's groundwater.
(B) Definitions. The following definitions shall apply to this section unless the context clearly indicates or requires a different meaning.
ANNULAR SPACE. The space between the casing or well screen and the wall of the borehole, or between drilling pipe and casing, or between two separate strings of casing.
AQUIFER. A subsurface water-bearing layer of soil, sand, gravel, or rock that will yield usable quantities of water to a well.
BOREHOLE. A hole drilled or bored into the earth, usually for exploratory or economic purposes; a hole into which casing, screen, and other materials may be installed to construct a well.
CASING. An impervious, durable pipe placed in a borehole to prevent the walls of the borehole from caving, and to seal off surface drainage or undesirable water, gas, or other fluids and prevent entrance into a well.
CLOSED HORIZONTAL LOOP GEOTHERMAL SYSTEM. A geothermal system that consists of the following basic elements: underground loops of piping; heat transfer fluid; a heat pump, and an air distribution system. An opening is made in the earth. A series of pipes are installed into the opening
and connected to a heat exchange system in the building. The pipes form a "closed loop" and are filled with a heat transfer fluid. The fluid is circulated through the piping from the opening into the heat exchanger and back. The system functions in the same manner as the open loop system except there is no pumping of groundwater. A horizontal closed loop geothermal system shall be no more than 20 feet deep.
CLOSED VERTICAL LOOP GEOTHERMAL SYSTEM. A geothermal system in which a borehole extends beneath the surface. Pipes are installed with U-bends at the bottom of the borehole. The pipes are connected to the heat exchanger and heat transfer fluid is circulated through the pipes.
DRINKING WATER. Water which is intended for human consumption and other domestic uses, and is considered to be free of harmful chemicals and disease-causing microorganisms.
GEOTHERMAL BOREHOLE. A hole drilled or bored into the earth into which piping is inserted for use in a geothermal system.
GEOTHERMAL SYSTEM. A system for heating and/or cooling buildings using the earth's thermal properties in conjunction with electricity.
GROUNDWATER. Water beneath the earth's surface that is located between saturated soil and rock that supplies wells and springs.
GROUT. A low permeability material that is emplaced in the space between the wall of the borehole and the casing of a well end, or placed in the annular space of the borehole. The emplacement of grout is to prevent the migration of water or fluid contaminants into and through the borehole. Grout shall consist of neat cement, high solids bentonite slurry, or hydrated bentonite chips.
HEAT TRANSFER FLUID. Any liquid used especially for the purpose of transferring thermal energy from the heat source to another location.
OPEN LOOP GEOTHERMAL SYSTEM. A geothermal system in which groundwater is pumped from a well into a heat exchanger located in a surface building. The water drawn from the earth is then pumped back into the aquifer through a different well or in some cases the same well (commonly referred to as "re-injection"). Alternatively, the groundwater could be discharged to a surface water body (also known as "pump and dump"). In the heating mode, cooler water is returned to the earth, while in the cooling mode, warmer water is returned to the surface water body.
PERMEABILITY. The propensity of a material to allow fluid to move through its pores or interstices. Permeability is an important soil parameter when flow of water through soil or rock is a matter of concern.
SEPARATION/ISOLATION DISTANCES. The distance of a source of contamination from a surface drinking water source, a groundwater source supply well, or any type of borehole.
WATER SUPPLY WELL. A well used for extracting groundwater for human consumption.
WELL. Any excavation that is drilled, cored, driven, dug, bored, augured, jetted, washed, or otherwise constructed for the purpose of exploring for groundwater, monitoring groundwater, utilizing the geothermal properties of the ground, or extracting water from or injecting water into an aquifer. WELL does not include an open ditch, drain tiles, an excavation made for obtaining or prospecting for oil, natural gas, minerals, or products mined or quarried, lateral geothermal heat exchange systems less than 20 feet deep, nor temporary dewatering wells such as those used during the construction of subsurface facilities only for the duration of the construction.
(C) Permit required.
(1) No person shall:
(a) Construct or install a geothermal system;
(b) Dig, bore, drill, replace, modify, repair, or destroy a well that is, is intended to be, or was part of a geothermal system; or
(c) Make any other excavation that may intersect groundwater without first obtaining a permit from the city and, for construction of a well, the Central Michigan Health Department.
(2) A permit is required for any closed loop horizontal and closed loop vertical geothermal system. (No permit shall be issued for any open loop geothermal system because such systems are prohibited by division (I) below.)
(D) Application procedure. Applications for city permits shall be made to the city DPW on approved forms and shall contain the information required on the form. Permits shall be issued for the particular parcel of property on which the geothermal system is to be constructed and/or installed. The application may be made by the property owner, a representative of the property owner authorized in writing by the property owner such as a tenant authorized under a lease, or the well driller, and shall be accompanied by the required filing fee. The locations of the loops that are part of any closed loop geothermal system shall be completely located within the property's boundaries.
(E) Well permits. All wells must be permitted by the Central Michigan District Health Department (or its successor agency) and must comply with the Michigan Water Well Construction and Pump Installation Code, Groundwater Quality Control, Part 127, 1978 P.A. 368, as amended, and all rules and regulations promulgated pursuant thereto, or any replacing statute and regulations. A site plan showing the generally proposed location, number of wells, and location of loops must be submitted to the City Engineer for review and approval. The plan must include the calculated, anticipated volume of grout that will be needed.
(F) Permit requirements.
(1) Permits may be issued only for closed loop geothermal systems.
(2) Boreholes shall be drilled by Michigan registered/licensed water well drillers.
(3) The property owner shall maintain a well log of the borehole and "as built" plans showing the location and specifications of closed loop geothermal system components.
(4) Borehole piping shall be high density polyethylene as specified in International Ground Source Heat Pump Association standards for closed loop heat pumps.
(5) The annular space of the boreholes must be grouted for the full depth of the borehole using high solid bentonite grout.
(6) Heat transfer fluids must be Environol 2000 manufactured by Water Furnace Company or another non-toxic, environmentally safe material approved by the City Engineer.
(G) Permit fee. The geothermal system permit fee shall be in the amount established from time-to-time by resolution of the City Commission and shall be paid when the application is filed.
(H) Permit revocation.
(1) The City Engineer may revoke a permit if:
(a) Any action or any geothermal system violates a provision of this section; or
(b) There are factual inaccuracies in a permit application or the documents supporting it.
(2) The City Engineer shall notify the property owner and occupant in writing of a permit revocation.
(3) The property owner or occupant may appeal a revocation to the City Manager who shall hold a hearing on that revocation to allow the appellant to prove the geothermal system complies with this section or that the statements in the application and supporting documents are true. Further appeals shall be to the Isabella County Circuit Court.
(4) When a permit is revoked, the property owner shall immediately abandon the geothermal system as required by this section. Except in cases where the City Engineer reasonably determines that groundwater contamination is an imminent risk, the obligation to abandon the geothermal system after revocation shall be stayed while any appeal is pending.
(I) Open loop systems prohibited. Open loop geothermal systems are prohibited.
(J) System testing. Pipes for geothermal system permitted under this section shall be tested hydrostatically at one and one-half times the maximum system design pressure, but not less than 100 psi (689 kPa), for a duration of not less than 15 minutes. All geothermal systems must be pressure checked by a licensed geothermal system contractor every five years from the date of its initial successful test. Results shall be filed with the City Engineer. If the test results show the system fails to meet these requirements, system shutdown and repairs shall be made at the direction of the City Engineer.
(K) System abandonment. Abandonment of a geothermal system shall comply with the laws, rules and regulations applicable to abandonment of water supply wells. Heat transfer fluid must be removed by displacement with grout. The top of the borehole must be uncovered and capped with grout.
(L) Conflict with other regulations. If any provision of this section conflicts with any applicable state or federal law, rule or regulation which is more strict or which is determined to preempt a provision of this section, the applicable state or federal requirement shall control.
(M) Violation and penalty. Regardless of § 52.99 which applies to violations of other sections of this chapter, any violation of any provision of this section shall constitute a municipal civil infraction punishable by a civil fine of up to $5,000. Each day of that a condition exists that violates any provision of this sections shall constitute a separate offense.
(Ord. 952, passed 8-24-09)